* Re:[PATCH]2.6.7 MSI-X Update
@ 2004-07-13 22:02 long
2004-07-15 2:14 ` [PATCH]2.6.7 " Roland Dreier
2004-07-18 1:25 ` Roland Dreier
0 siblings, 2 replies; 4+ messages in thread
From: long @ 2004-07-13 22:02 UTC (permalink / raw)
To: roland; +Cc: ak, akpm, greg, jgazik, linux-kernel, tom.l.nguyen, zwane
On Friday, June 25, 2004 6:39 PM, Roland Dreier wrote:
>To summarize:
> 1) free_irq() should not have the function of disabling MSI, since
> drivers probably don't want to disable MSI or free MSI-X vectors
> just because they call free_irq()
Agree. Thanks for your inputs.
> 2) removing this overloaded function from free_irq() will also make
> driver code clearer and easier to maintain.
I need this overloaded function to keep track of the state of each
MSI/MSI-X vector. This allows me to generate a BUG_ON() if driver
calls pci_disable_msi()/pci_disable_msix() without calling free_irq()
for all MSI/MSI-X vector(s).
I include the update to previous patch. Please let me know what you
think.
Thanks,
Long
---------------------------------------------------------------------
diff -urN patch-2.6.7-msix-src1/Documentation/MSI-HOWTO.txt patch-2.6.7-msix-src2/Documentation/MSI-HOWTO.txt
--- patch-2.6.7-msix-src1/Documentation/MSI-HOWTO.txt 2004-06-25 16:10:58.000000000 -0400
+++ patch-2.6.7-msix-src2/Documentation/MSI-HOWTO.txt 2004-07-13 12:45:45.000000000 -0400
@@ -113,7 +113,7 @@
messages regardless of a device function is capable of supporting
more than one vector. To enable MSI on a device function's MSI
capability structure requires a device driver to call the function
-pci_enable_msi() explicitly.
+pci_enable_msi() explicitly.
5.2.1 API pci_enable_msi
@@ -132,11 +132,15 @@
void pci_disable_msi(struct pci_dev *dev)
-This API is needed to encounter the case where a device driver is
-unloaded without doing request_irq on assigned MSI vector results
-a device being left in MSI mode and not be able to recover without
-rebooting. This API provides a device driver an ability to recover
-and resolves vector leakage.
+This API should always be used to undo the effect of pci_enable_msi()
+when a device driver is unloading. This API restores dev->irq with
+the pre-assigned IOAPIC vector and switches a device's interrupt
+mode to PCI pin-irq assertion/INTx emulation mode.
+
+Note that a device driver should always call free_irq() on MSI vector
+it has done request_irq() on before calling this API. Failure to do
+so results a BUG_ON() and a device will be left with MSI enabled and
+leaks its vector.
5.2.3 MSI mode vs. legacy mode diagram
@@ -148,8 +152,7 @@
| | <=============== | |
| MSI MODE | | PIN-IRQ ASSERTION MODE |
| | ===============> | |
- ------------ free_irq/ ------------------------
- pci_disable_msi
+ ------------ pci_disable_msi ------------------------
Figure 1.0 MSI Mode vs. Legacy Mode
@@ -161,17 +164,24 @@
stored in dev->irq will be saved by the PCI subsystem and a new
assigned MSI vector will replace dev->irq.
-To return back to its default mode, a device driver must call
-free_irq() using the allocated MSI vector. The PCI subsystem restores a
-device's dev->irq with a pre-assigned IOAPIC vector and marks released
-MSI vector as unused. Once being marked as unused, there is no
-guarantee that the PCI subsystem will reserve this MSI vector for a
-device. Depending on the availability of current PCI vector resources
-and the number of MSI/MSI-X requests from other drivers, this MSI
-may be re-assigned. For the case where the PCI subsystem re-assigned
-this MSI vector another driver, a request to switching back to MSI
-mode may result in being assigned a different MSI vector or a failure
-if no more vectors are available.
+To return back to its default mode, a device driver should always call
+pci_disable_msi() to undo the effect of pci_enable_msi(). Note that a
+device driver should always call free_irq() on MSI vector it has done
+request_irq() on before calling pci_disable_msi(). Failure to do so
+results a BUG_ON() and a device will be left with MSI enabled and
+leaks its vector. Otherwise, the PCI subsystem restores a device's
+dev->irq with a pre-assigned IOAPIC vector and marks released
+MSI vector as unused.
+
+Once being marked as unused, there is no guarantee that the PCI
+subsystem will reserve this MSI vector for a device. Depending on
+the availability of current PCI vector resources and the number of
+MSI/MSI-X requests from other drivers, this MSI may be re-assigned.
+
+For the case where the PCI subsystem re-assigned this MSI vector
+another driver, a request to switching back to MSI mode may result
+in being assigned a different MSI vector or a failure if no more
+vectors are available.
5.3 Configuring for MSI-X support
@@ -328,15 +338,11 @@
void pci_disable_msix(struct pci_dev *dev)
-This API is needed to encounter the case where a device driver is
-unloaded without doing request_irq on all ssigned MSI-X vector
-results a device being left in MSI-x mode and not be able to recover
-without rebooting. For example, a device driver does pci_enable_msix
-and is allocated 2 vectors, then correctly does request_irq/free_irq
-on one vector but does not touch the second vector. When a device
-driver is unloaded, it will be left in MSI-X mode. This API provides
-a device driver an ability to recover without rebooting and resolves
-vector leakage.
+This API should always be used to undo the effect of pci_enable_msix()
+when a device driver is unloading. Note that a device driver should
+always call free_irq() on all MSI-X vectors it has done request_irq()
+on before calling this API. Failure to do so results a BUG_ON() and
+a device will be left with MSI-X enabled and leaks its vectors.
5.3.6 MSI-X mode vs. legacy mode diagram
@@ -348,8 +354,7 @@
| | <=============== | |
| MSI-X MODE | | PIN-IRQ ASSERTION MODE |
| | ===============> | |
- ------------ (n)free_irq/ ------------------------
- pci_disable_msix
+ ------------ pci_disable_msix ------------------------
Figure 2.0 MSI-X Mode vs. Legacy Mode
@@ -358,30 +363,29 @@
device's interrupt mode to MSI-X mode. A pre-assigned IOAPIC vector
stored in dev->irq will be saved by the PCI subsystem; however,
unlike MSI mode, the PCI subsystem will not replace dev->irq with
-assigned MSI-x vector because the PCI subsystem already writes the 1:1
+assigned MSI-X vector because the PCI subsystem already writes the 1:1
vector-to-entry mapping into the field vector of each element
specified in second argument.
-To return back to its default mode, a device driver requires to call
-free_irq() on all allocated MSI vectors associated with doing
-request_irq. Unlike MSI mode, the PCI subsystem switches a device
-function back to its default legacy mode if and only if its device
-driver successfully releases all allocated MSI-X vectors correctly
-associated with request_irq/free_irq.
-
-Note that if a device still operates in MSI-X mode, its device
-driver can use request_irq/free_irq to any vectors in subset n. When
-the PCI subsystem detects all MSI-X vectors being released by a device
-driver, it will switches a function's interrupt mode from MSI-X mode
-to legacy mode and mark all allocated MSI-X vectors as unused. Once
-being marked as unused, there is no guarantee that the PCI subsystem
-will reserve these MSI-X vectors for a device. Depending on the
-availability of current PCI vector resources and the number of
+To return back to its default mode, a device driver should always call
+pci_disable_msix() to undo the effect of pci_enable_msix(). Note that
+a device driver should always call free_irq() on all MSI-X vectors it
+has done request_irq() on before calling pci_disable_msix(). Failure
+to do so results a BUG_ON() and a device will be left with MSI-X
+enabled and leaks its vectors. Otherwise, the PCI subsystem switches a
+device function's interrupt mode from MSI-X mode to legacy mode and
+marks all allocated MSI-X vectors as unused.
+
+Once being marked as unused, there is no guarantee that the PCI
+subsystem will reserve these MSI-X vectors for a device. Depending on
+the availability of current PCI vector resources and the number of
MSI/MSI-X requests from other drivers, these MSI-X vectors may be
-re-assigned. For the case where the PCI subsystem re-assigned
-these MSI-X vectors to other driver, a request to switching back to
-MSI-X mode may result being assigned with another set of MSI-X vectors
-or a failure.
+re-assigned.
+
+For the case where the PCI subsystem re-assigned these MSI-X vectors
+to other driver, a request to switching back to MSI-X mode may result
+being assigned with another set of MSI-X vectors or a failure if no
+more vectors are available.
5.4 Handling function implementng both MSI and MSI-X capabilities
diff -urN patch-2.6.7-msix-src1/drivers/pci/msi.c patch-2.6.7-msix-src2/drivers/pci/msi.c
--- patch-2.6.7-msix-src1/drivers/pci/msi.c 2004-06-25 14:43:10.000000000 -0400
+++ patch-2.6.7-msix-src2/drivers/pci/msi.c 2004-07-13 09:30:44.000000000 -0400
@@ -779,10 +779,8 @@
dev->irq);
BUG_ON(entry->msi_attrib.state > 0);
} else {
- if (vector_irq[dev->irq] != 0) {
- vector_irq[dev->irq] = 0; /* free it */
- nr_released_vectors++;
- }
+ vector_irq[dev->irq] = 0; /* free it */
+ nr_released_vectors++;
default_vector = entry->msi_attrib.default_vector;
spin_unlock_irqrestore(&msi_lock, flags);
/* Restore dev->irq to its default pin-assertion vector */
@@ -794,58 +792,14 @@
static void release_msi(unsigned int vector)
{
- int type, default_vector;
struct msi_desc *entry;
- struct pci_dev *dev;
unsigned long flags;
spin_lock_irqsave(&msi_lock, flags);
entry = msi_desc[vector];
- if (!entry || !entry->dev) {
- spin_unlock_irqrestore(&msi_lock, flags);
- return;
- }
- dev = entry->dev;
- type = entry->msi_attrib.type;
- entry->msi_attrib.state = 0; /* Mark it not active */
- default_vector = entry->msi_attrib.default_vector;
+ if (entry && entry->dev)
+ entry->msi_attrib.state = 0; /* Mark it not active */
spin_unlock_irqrestore(&msi_lock, flags);
- switch (type) {
- case PCI_CAP_ID_MSI:
- spin_lock_irqsave(&msi_lock, flags);
- vector_irq[vector] = 0; /* Mark it free */
- nr_released_vectors++;
- spin_unlock_irqrestore(&msi_lock, flags);
- break;
- case PCI_CAP_ID_MSIX:
- spin_lock_irqsave(&msi_lock, flags);
- while (vector != entry->link.tail) {
- entry = msi_desc[entry->link.tail];
- if (!entry->msi_attrib.state)
- continue;
- spin_unlock_irqrestore(&msi_lock, flags);
- /*
- * Device still operates in MSI-X mode. Do not
- * switch interrupt mode
- */
- return;
- }
- entry = msi_desc[vector];
- vector_irq[vector] = 0; /* Mark it free */
- nr_released_vectors++;
- while (vector != entry->link.tail) {
- vector_irq[entry->link.tail] = 0; /* Mark it free */
- nr_released_vectors++;
- entry = msi_desc[entry->link.tail];
- }
- spin_unlock_irqrestore(&msi_lock, flags);
- break;
- default:
- return;
- }
- /* Restore dev->irq to its default pin-assertion vector */
- dev->irq = default_vector;
- disable_msi_mode(dev, pci_find_capability(dev, type), type);
}
static int msi_free_vector(struct pci_dev* dev, int vector, int reassign)
@@ -1074,6 +1028,7 @@
pci_read_config_word(dev, msi_control_reg(pos), &control);
if (!(control & PCI_MSIX_FLAGS_ENABLE))
return;
+
temp = dev->irq;
if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
int state, vector, head, tail = 0, warning = 0;
@@ -1086,10 +1041,8 @@
if (state)
warning = 1;
else {
- if (vector_irq[vector] != 0) {
- vector_irq[vector] = 0; /* free it */
- nr_released_vectors++;
- }
+ vector_irq[vector] = 0; /* free it */
+ nr_released_vectors++;
}
tail = msi_desc[vector]->link.tail;
vector = tail;
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH]2.6.7 MSI-X Update
2004-07-13 22:02 Re:[PATCH]2.6.7 MSI-X Update long
@ 2004-07-15 2:14 ` Roland Dreier
2004-07-18 1:25 ` Roland Dreier
1 sibling, 0 replies; 4+ messages in thread
From: Roland Dreier @ 2004-07-15 2:14 UTC (permalink / raw)
To: long; +Cc: ak, akpm, greg, jgazik, linux-kernel, tom.l.nguyen, zwane
Long, welcome back. I will review your patch as soon as I have a
little free time.
Roland> 2) removing this overloaded function from free_irq() will
Roland> also make driver code clearer and easier to maintain.
long> I need this overloaded function to keep track of the state
long> of each MSI/MSI-X vector. This allows me to generate a
long> BUG_ON() if driver calls
long> pci_disable_msi()/pci_disable_msix() without calling
long> free_irq() for all MSI/MSI-X vector(s).
I think it's OK to keep track of which MSI/MSI-X vectors have ISRs
attached and which don't. However I don't think free_irq() should
return a vector to the free pool (that might be used by other
devices). In other words it should be OK for a correct driver to do
pci_enable_msix(pdev...);
request_irq(msix_vector1);
free_irq(msix_vector1);
request_irq(msix_vector1);
free_irq(msix_vector1);
pci_disable_msix(pdev...);
(obviously with some code in between operations).
I think we agree on this and I will read your code to find out what
you actually do but I just wanted to make my proposed interface clear.
Thanks,
Roland
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH]2.6.7 MSI-X Update
2004-07-13 22:02 Re:[PATCH]2.6.7 MSI-X Update long
2004-07-15 2:14 ` [PATCH]2.6.7 " Roland Dreier
@ 2004-07-18 1:25 ` Roland Dreier
1 sibling, 0 replies; 4+ messages in thread
From: Roland Dreier @ 2004-07-18 1:25 UTC (permalink / raw)
To: long; +Cc: ak, akpm, greg, jgarzik, linux-kernel, tom.l.nguyen, zwane
This looks great now. I've tested both MSI and MSI-X with my mthca
driver, and everything works well.
I've rediffed against latest bk. Greg, I think this is ready to be
applied. It would be great to get this in before 2.6.8, since current
MSI-X support is not very usable. For the changelog, here's a summary
of the patch:
MSI-X update:
- msi.c uses pci_{read,write}_config_xxx instead of raw access to bus->ops
- separate MSI and MSI-X APIs to pci_enable_msi()/pci_disable_msi()
and pci_enable_msix()/pci_disable_msix()
- MSI/MSI-X vectors are no longer freed by free_irq(); devices keep
allocated vectors until pci_disable_msi()/pci_disable_msix()
Thanks,
Roland
Signed-off-by: Roland Dreier <roland@topspin.com>
From: "Nguyen, Tom L" <tom.l.nguyen@intel.com>
Index: linux-bk/Documentation/MSI-HOWTO.txt
===================================================================
--- linux-bk.orig/Documentation/MSI-HOWTO.txt
+++ linux-bk/Documentation/MSI-HOWTO.txt
@@ -3,13 +3,14 @@
10/03/2003
Revised Feb 12, 2004 by Martine Silbermann
email: Martine.Silbermann@hp.com
+ Revised Jun 25, 2004 by Tom L Nguyen
1. About this guide
-This guide describes the basics of Message Signaled Interrupts(MSI), the
-advantages of using MSI over traditional interrupt mechanisms, and how
-to enable your driver to use MSI or MSI-X. Also included is a Frequently
-Asked Questions.
+This guide describes the basics of Message Signaled Interrupts (MSI),
+the advantages of using MSI over traditional interrupt mechanisms,
+and how to enable your driver to use MSI or MSI-X. Also included is
+a Frequently Asked Questions.
2. Copyright 2003 Intel Corporation
@@ -35,7 +36,7 @@
the MSI/MSI-X capability structure in its PCI capability list. The
device function may implement both the MSI capability structure and
the MSI-X capability structure; however, the bus driver should not
-enable both, but instead enable only the MSI-X capability structure.
+enable both.
The MSI capability structure contains Message Control register,
Message Address register and Message Data register. These registers
@@ -86,7 +87,7 @@
support for better interrupt performance.
Using MSI enables the device functions to support two or more
-vectors, which can be configure to target different CPU's to
+vectors, which can be configured to target different CPU's to
increase scalability.
5. Configuring a driver to use MSI/MSI-X
@@ -95,26 +96,53 @@
support this capability. The CONFIG_PCI_USE_VECTOR kernel option
must be selected to enable MSI/MSI-X support.
-5.1 Including MSI support into the kernel
+5.1 Including MSI/MSI-X support into the kernel
-To allow MSI-Capable device drivers to selectively enable MSI (using
-pci_enable_msi as described below), the VECTOR based scheme needs to
-be enabled by setting CONFIG_PCI_USE_VECTOR.
+To allow MSI/MSI-X capable device drivers to selectively enable
+MSI/MSI-X (using pci_enable_msi()/pci_enable_msix() as described
+below), the VECTOR based scheme needs to be enabled by setting
+CONFIG_PCI_USE_VECTOR during kernel config.
Since the target of the inbound message is the local APIC, providing
-CONFIG_PCI_USE_VECTOR is dependent on whether CONFIG_X86_LOCAL_APIC
-is enabled or not.
+CONFIG_X86_LOCAL_APIC must be enabled as well as CONFIG_PCI_USE_VECTOR.
-int pci_enable_msi(struct pci_dev *)
+5.2 Configuring for MSI support
+
+Due to the non-contiguous fashion in vector assignment of the
+existing Linux kernel, this version does not support multiple
+messages regardless of a device function is capable of supporting
+more than one vector. To enable MSI on a device function's MSI
+capability structure requires a device driver to call the function
+pci_enable_msi() explicitly.
+
+5.2.1 API pci_enable_msi
+
+int pci_enable_msi(struct pci_dev *dev)
With this new API, any existing device driver, which like to have
-MSI enabled on its device function, must call this explicitly. A
-successful call will initialize the MSI/MSI-X capability structure
-with ONE vector, regardless of whether the device function is
+MSI enabled on its device function, must call this API to enable MSI
+A successful call will initialize the MSI capability structure
+with ONE vector, regardless of whether a device function is
capable of supporting multiple messages. This vector replaces the
pre-assigned dev->irq with a new MSI vector. To avoid the conflict
of new assigned vector with existing pre-assigned vector requires
-the device driver to call this API before calling request_irq(...).
+a device driver to call this API before calling request_irq().
+
+5.2.2 API pci_disable_msi
+
+void pci_disable_msi(struct pci_dev *dev)
+
+This API should always be used to undo the effect of pci_enable_msi()
+when a device driver is unloading. This API restores dev->irq with
+the pre-assigned IOAPIC vector and switches a device's interrupt
+mode to PCI pin-irq assertion/INTx emulation mode.
+
+Note that a device driver should always call free_irq() on MSI vector
+it has done request_irq() on before calling this API. Failure to do
+so results a BUG_ON() and a device will be left with MSI enabled and
+leaks its vector.
+
+5.2.3 MSI mode vs. legacy mode diagram
The below diagram shows the events, which switches the interrupt
mode on the MSI-capable device function between MSI mode and
@@ -124,105 +152,258 @@
| | <=============== | |
| MSI MODE | | PIN-IRQ ASSERTION MODE |
| | ===============> | |
- ------------ free_irq ------------------------
+ ------------ pci_disable_msi ------------------------
-5.2 Configuring for MSI support
-Due to the non-contiguous fashion in vector assignment of the
-existing Linux kernel, this version does not support multiple
-messages regardless of the device function is capable of supporting
-more than one vector. The bus driver initializes only entry 0 of
-this capability if pci_enable_msi(...) is called successfully by
-the device driver.
+Figure 1.0 MSI Mode vs. Legacy Mode
+
+In Figure 1.0, a device operates by default in legacy mode. Legacy
+in this context means PCI pin-irq assertion or PCI-Express INTx
+emulation. A successful MSI request (using pci_enable_msi()) switches
+a device's interrupt mode to MSI mode. A pre-assigned IOAPIC vector
+stored in dev->irq will be saved by the PCI subsystem and a new
+assigned MSI vector will replace dev->irq.
+
+To return back to its default mode, a device driver should always call
+pci_disable_msi() to undo the effect of pci_enable_msi(). Note that a
+device driver should always call free_irq() on MSI vector it has done
+request_irq() on before calling pci_disable_msi(). Failure to do so
+results a BUG_ON() and a device will be left with MSI enabled and
+leaks its vector. Otherwise, the PCI subsystem restores a device's
+dev->irq with a pre-assigned IOAPIC vector and marks released
+MSI vector as unused.
+
+Once being marked as unused, there is no guarantee that the PCI
+subsystem will reserve this MSI vector for a device. Depending on
+the availability of current PCI vector resources and the number of
+MSI/MSI-X requests from other drivers, this MSI may be re-assigned.
+
+For the case where the PCI subsystem re-assigned this MSI vector
+another driver, a request to switching back to MSI mode may result
+in being assigned a different MSI vector or a failure if no more
+vectors are available.
5.3 Configuring for MSI-X support
-Both the MSI capability structure and the MSI-X capability structure
-share the same above semantics; however, due to the ability of the
-system software to configure each vector of the MSI-X capability
-structure with an independent message address and message data, the
-non-contiguous fashion in vector assignment of the existing Linux
-kernel has no impact on supporting multiple messages on an MSI-X
-capable device functions. By default, as mentioned above, ONE vector
-should be always allocated to the MSI-X capability structure at
-entry 0. The bus driver does not initialize other entries of the
-MSI-X table.
-
-Note that the PCI subsystem should have full control of a MSI-X
-table that resides in Memory Space. The software device driver
-should not access this table.
-
-To request for additional vectors, the device software driver should
-call function msi_alloc_vectors(). It is recommended that the
-software driver should call this function once during the
+Due to the ability of the system software to configure each vector of
+the MSI-X capability structure with an independent message address
+and message data, the non-contiguous fashion in vector assignment of
+the existing Linux kernel has no impact on supporting multiple
+messages on an MSI-X capable device functions. To enable MSI-X on
+a device function's MSI-X capability structure requires its device
+driver to call the function pci_enable_msix() explicitly.
+
+The function pci_enable_msix(), once invoked, enables either
+all or nothing, depending on the current availability of PCI vector
+resources. If the PCI vector resources are available for the number
+of vectors requested by a device driver, this function will configure
+the MSI-X table of the MSI-X capability structure of a device with
+requested messages. To emphasize this reason, for example, a device
+may be capable for supporting the maximum of 32 vectors while its
+software driver usually may request 4 vectors. It is recommended
+that the device driver should call this function once during the
initialization phase of the device driver.
-The function msi_alloc_vectors(), once invoked, enables either
-all or nothing, depending on the current availability of vector
-resources. If no vector resources are available, the device function
-still works with ONE vector. If the vector resources are available
-for the number of vectors requested by the driver, this function
-will reconfigure the MSI-X capability structure of the device with
-additional messages, starting from entry 1. To emphasize this
-reason, for example, the device may be capable for supporting the
-maximum of 32 vectors while its software driver usually may request
-4 vectors.
-
-For each vector, after this successful call, the device driver is
-responsible to call other functions like request_irq(), enable_irq(),
-etc. to enable this vector with its corresponding interrupt service
-handler. It is the device driver's choice to have all vectors shared
-the same interrupt service handler or each vector with a unique
-interrupt service handler.
-
-In addition to the function msi_alloc_vectors(), another function
-msi_free_vectors() is provided to allow the software driver to
-release a number of vectors back to the vector resources. Once
-invoked, the PCI subsystem disables (masks) each vector released.
-These vectors are no longer valid for the hardware device and its
-software driver to use. Like free_irq, it recommends that the
-device driver should also call msi_free_vectors to release all
-additional vectors previously requested.
-
-int msi_alloc_vectors(struct pci_dev *dev, int *vector, int nvec)
-
-This API enables the software driver to request the PCI subsystem
-for additional messages. Depending on the number of vectors
-available, the PCI subsystem enables either all or nothing.
+Unlike the function pci_enable_msi(), the function pci_enable_msix()
+does not replace the pre-assigned IOAPIC dev->irq with a new MSI
+vector because the PCI subsystem writes the 1:1 vector-to-entry mapping
+into the field vector of each element contained in a second argument.
+Note that the pre-assigned IO-APIC dev->irq is valid only if the device
+operates in PIN-IRQ assertion mode. In MSI-X mode, any attempt of
+using dev->irq by the device driver to request for interrupt service
+may result unpredictabe behavior.
+
+For each MSI-X vector granted, a device driver is responsible to call
+other functions like request_irq(), enable_irq(), etc. to enable
+this vector with its corresponding interrupt service handler. It is
+a device driver's choice to assign all vectors with the same
+interrupt service handler or each vector with a unique interrupt
+service handler.
+
+5.3.1 Handling MMIO address space of MSI-X Table
+
+The PCI 3.0 specification has implementation notes that MMIO address
+space for a device's MSI-X structure should be isolated so that the
+software system can set different page for controlling accesses to
+the MSI-X structure. The implementation of MSI patch requires the PCI
+subsystem, not a device driver, to maintain full control of the MSI-X
+table/MSI-X PBA and MMIO address space of the MSI-X table/MSI-X PBA.
+A device driver is prohibited from requesting the MMIO address space
+of the MSI-X table/MSI-X PBA. Otherwise, the PCI subsystem will fail
+enabling MSI-X on its hardware device when it calls the function
+pci_enable_msix().
+
+5.3.2 Handling MSI-X allocation
+
+Determining the number of MSI-X vectors allocated to a function is
+dependent on the number of MSI capable devices and MSI-X capable
+devices populated in the system. The policy of allocating MSI-X
+vectors to a function is defined as the following:
+
+#of MSI-X vectors allocated to a function = (x - y)/z where
+
+x = The number of available PCI vector resources by the time
+ the device driver calls pci_enable_msix(). The PCI vector
+ resources is the sum of the number of unassigned vectors
+ (new) and the number of released vectors when any MSI/MSI-X
+ device driver switches its hardware device back to a legacy
+ mode or is hot-removed. The number of unassigned vectors
+ may exclude some vectors reserved, as defined in parameter
+ NR_HP_RESERVED_VECTORS, for the case where the system is
+ capable of supporting hot-add/hot-remove operations. Users
+ may change the value defined in NR_HR_RESERVED_VECTORS to
+ meet their specific needs.
+
+y = The number of MSI capable devices populated in the system.
+ This policy ensures that each MSI capable device has its
+ vector reserved to avoid the case where some MSI-X capable
+ drivers may attempt to claim all available vector resources.
+
+z = The number of MSI-X capable devices pupulated in the system.
+ This policy ensures that maximum (x - y) is distributed
+ evenly among MSI-X capable devices.
+
+Note that the PCI subsystem scans y and z during a bus enumeration.
+When the PCI subsystem completes configuring MSI/MSI-X capability
+structure of a device as requested by its device driver, y/z is
+decremented accordingly.
+
+5.3.3 Handling MSI-X shortages
+
+For the case where fewer MSI-X vectors are allocated to a function
+than requested, the function pci_enable_msix() will return the
+maximum number of MSI-X vectors available to the caller. A device
+driver may re-send its request with fewer or equal vectors indicated
+in a return. For example, if a device driver requests 5 vectors, but
+the number of available vectors is 3 vectors, a value of 3 will be a
+return as a result of pci_enable_msix() call. A function could be
+designed for its driver to use only 3 MSI-X table entries as
+different combinations as ABC--, A-B-C, A--CB, etc. Note that this
+patch does not support multiple entries with the same vector. Such
+attempt by a device driver to use 5 MSI-X table entries with 3 vectors
+as ABBCC, AABCC, BCCBA, etc will result as a failure by the function
+pci_enable_msix(). Below are the reasons why supporting multiple
+entries with the same vector is an undesirable solution.
+
+ - The PCI subsystem can not determine which entry, which
+ generated the message, to mask/unmask MSI while handling
+ software driver ISR. Attempting to walk through all MSI-X
+ table entries (2048 max) to mask/unmask any match vector
+ is an undesirable solution.
+
+ - Walk through all MSI-X table entries (2048 max) to handle
+ SMP affinity of any match vector is an undesirable solution.
+
+5.3.4 API pci_enable_msix
+
+int pci_enable_msix(struct pci_dev *dev, u32 *entries, int nvec)
+
+This API enables a device driver to request the PCI subsystem
+for enabling MSI-X messages on its hardware device. Depending on
+the availability of PCI vectors resources, the PCI subsystem enables
+either all or nothing.
Argument dev points to the device (pci_dev) structure.
-Argument vector is a pointer of integer type. The number of
-elements is indicated in argument nvec.
+
+Argument entries is a pointer of unsigned integer type. The number of
+elements is indicated in argument nvec. The content of each element
+will be mapped to the following struct defined in /driver/pci/msi.h.
+
+struct msix_entry {
+ u16 vector; /* kernel uses to write alloc vector */
+ u16 entry; /* driver uses to specify entry */
+};
+
+A device driver is responsible for initializing the field entry of
+each element with unique entry supported by MSI-X table. Otherwise,
+-EINVAL will be returned as a result. A successful return of zero
+indicates the PCI subsystem completes initializing each of requested
+entries of the MSI-X table with message address and message data.
+Last but not least, the PCI subsystem will write the 1:1
+vector-to-entry mapping into the field vector of each element. A
+device driver is responsible of keeping track of allocated MSI-X
+vectors in its internal data structure.
+
Argument nvec is an integer indicating the number of messages
requested.
-A return of zero indicates that the number of allocated vector is
-successfully allocated. Otherwise, indicate resources not
-available.
-
-int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec)
-
-This API enables the software driver to inform the PCI subsystem
-that it is willing to release a number of vectors back to the
-MSI resource pool. Once invoked, the PCI subsystem disables each
-MSI-X entry associated with each vector stored in the argument 2.
-These vectors are no longer valid for the hardware device and
-its software driver to use.
-Argument dev points to the device (pci_dev) structure.
-Argument vector is a pointer of integer type. The number of
-elements is indicated in argument nvec.
-Argument nvec is an integer indicating the number of messages
-released.
-A return of zero indicates that the number of allocated vectors
-is successfully released. Otherwise, indicates a failure.
+A return of zero indicates that the number of MSI-X vectors is
+successfully allocated. A return of greater than zero indicates
+MSI-X vector shortage. Or a return of less than zero indicates
+a failure. This failure may be a result of duplicate entries
+specified in second argument, or a result of no available vector,
+or a result of failing to initialize MSI-X table entries.
+
+5.3.5 API pci_disable_msix
+
+void pci_disable_msix(struct pci_dev *dev)
+
+This API should always be used to undo the effect of pci_enable_msix()
+when a device driver is unloading. Note that a device driver should
+always call free_irq() on all MSI-X vectors it has done request_irq()
+on before calling this API. Failure to do so results a BUG_ON() and
+a device will be left with MSI-X enabled and leaks its vectors.
+
+5.3.6 MSI-X mode vs. legacy mode diagram
+
+The below diagram shows the events, which switches the interrupt
+mode on the MSI-X capable device function between MSI-X mode and
+PIN-IRQ assertion mode (legacy).
+
+ ------------ pci_enable_msix(,,n) ------------------------
+ | | <=============== | |
+ | MSI-X MODE | | PIN-IRQ ASSERTION MODE |
+ | | ===============> | |
+ ------------ pci_disable_msix ------------------------
+
+Figure 2.0 MSI-X Mode vs. Legacy Mode
+
+In Figure 2.0, a device operates by default in legacy mode. A
+successful MSI-X request (using pci_enable_msix()) switches a
+device's interrupt mode to MSI-X mode. A pre-assigned IOAPIC vector
+stored in dev->irq will be saved by the PCI subsystem; however,
+unlike MSI mode, the PCI subsystem will not replace dev->irq with
+assigned MSI-X vector because the PCI subsystem already writes the 1:1
+vector-to-entry mapping into the field vector of each element
+specified in second argument.
+
+To return back to its default mode, a device driver should always call
+pci_disable_msix() to undo the effect of pci_enable_msix(). Note that
+a device driver should always call free_irq() on all MSI-X vectors it
+has done request_irq() on before calling pci_disable_msix(). Failure
+to do so results a BUG_ON() and a device will be left with MSI-X
+enabled and leaks its vectors. Otherwise, the PCI subsystem switches a
+device function's interrupt mode from MSI-X mode to legacy mode and
+marks all allocated MSI-X vectors as unused.
+
+Once being marked as unused, there is no guarantee that the PCI
+subsystem will reserve these MSI-X vectors for a device. Depending on
+the availability of current PCI vector resources and the number of
+MSI/MSI-X requests from other drivers, these MSI-X vectors may be
+re-assigned.
+
+For the case where the PCI subsystem re-assigned these MSI-X vectors
+to other driver, a request to switching back to MSI-X mode may result
+being assigned with another set of MSI-X vectors or a failure if no
+more vectors are available.
+
+5.4 Handling function implementng both MSI and MSI-X capabilities
+
+For the case where a function implements both MSI and MSI-X
+capabilities, the PCI subsystem enables a device to run either in MSI
+mode or MSI-X mode but not both. A device driver determines whether it
+wants MSI or MSI-X enabled on its hardware device. Once a device
+driver requests for MSI, for example, it is prohibited to request for
+MSI-X; in other words, a device driver is not permitted to ping-pong
+between MSI mod MSI-X mode during a run-time.
-5.4 Hardware requirements for MSI support
-MSI support requires support from both system hardware and
+5.5 Hardware requirements for MSI/MSI-X support
+MSI/MSI-X support requires support from both system hardware and
individual hardware device functions.
-5.4.1 System hardware support
+5.5.1 System hardware support
Since the target of MSI address is the local APIC CPU, enabling
-MSI support in Linux kernel is dependent on whether existing
+MSI/MSI-X support in Linux kernel is dependent on whether existing
system hardware supports local APIC. Users should verify their
system whether it runs when CONFIG_X86_LOCAL_APIC=y.
@@ -231,14 +412,14 @@
CONFIG_X86_LOCAL_APIC. Once CONFIG_X86_LOCAL_APIC=y, setting
CONFIG_PCI_USE_VECTOR enables the VECTOR based scheme and
the option for MSI-capable device drivers to selectively enable
-MSI (using pci_enable_msi as described below).
+MSI/MSI-X.
-Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI
-vector is allocated new during runtime and MSI support does not
-depend on BIOS support. This key independency enables MSI support
-on future IOxAPIC free platform.
+Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI/MSI-X
+vector is allocated new during runtime and MSI/MSI-X support does not
+depend on BIOS support. This key independency enables MSI/MSI-X
+support on future IOxAPIC free platform.
-5.4.2 Device hardware support
+5.5.2 Device hardware support
The hardware device function supports MSI by indicating the
MSI/MSI-X capability structure on its PCI capability list. By
default, this capability structure will not be initialized by
@@ -249,17 +430,19 @@
MSI-capable hardware is responsible for whether calling
pci_enable_msi or not. A return of zero indicates the kernel
successfully initializes the MSI/MSI-X capability structure of the
-device funtion. The device function is now running on MSI mode.
+device funtion. The device function is now running on MSI/MSI-X mode.
-5.5 How to tell whether MSI is enabled on device function
+5.6 How to tell whether MSI/MSI-X is enabled on device function
-At the driver level, a return of zero from pci_enable_msi(...)
-indicates to the device driver that its device function is
-initialized successfully and ready to run in MSI mode.
+At the driver level, a return of zero from the function call of
+pci_enable_msi()/pci_enable_msix() indicates to a device driver that
+its device function is initialized successfully and ready to run in
+MSI/MSI-X mode.
At the user level, users can use command 'cat /proc/interrupts'
-to display the vector allocated for the device and its interrupt
-mode, as shown below.
+to display the vector allocated for a device and its interrupt
+MSI/MSI-X mode ("PCI MSI"/"PCI MSIX"). Below shows below MSI mode is
+enabled on a SCSI Adaptec 39320D Ultra320.
CPU0 CPU1
0: 324639 0 IO-APIC-edge timer
Index: linux-bk/drivers/pci/msi.c
===================================================================
--- linux-bk.orig/drivers/pci/msi.c
+++ linux-bk/drivers/pci/msi.c
@@ -67,12 +67,10 @@
unsigned int mask_bits;
pos = entry->mask_base;
- entry->dev->bus->ops->read(entry->dev->bus, entry->dev->devfn,
- pos, 4, &mask_bits);
+ pci_read_config_dword(entry->dev, pos, &mask_bits);
mask_bits &= ~(1);
mask_bits |= flag;
- entry->dev->bus->ops->write(entry->dev->bus, entry->dev->devfn,
- pos, 4, mask_bits);
+ pci_write_config_dword(entry->dev, pos, mask_bits);
break;
}
case PCI_CAP_ID_MSIX:
@@ -105,15 +103,13 @@
if (!(pos = pci_find_capability(entry->dev, PCI_CAP_ID_MSI)))
return;
- entry->dev->bus->ops->read(entry->dev->bus, entry->dev->devfn,
- msi_lower_address_reg(pos), 4,
+ pci_read_config_dword(entry->dev, msi_lower_address_reg(pos),
&address.lo_address.value);
address.lo_address.value &= MSI_ADDRESS_DEST_ID_MASK;
address.lo_address.value |= (cpu_mask_to_apicid(cpu_mask) <<
MSI_TARGET_CPU_SHIFT);
entry->msi_attrib.current_cpu = cpu_mask_to_apicid(cpu_mask);
- entry->dev->bus->ops->write(entry->dev->bus, entry->dev->devfn,
- msi_lower_address_reg(pos), 4,
+ pci_write_config_dword(entry->dev, msi_lower_address_reg(pos),
address.lo_address.value);
break;
}
@@ -158,13 +154,25 @@
static unsigned int startup_msi_irq_wo_maskbit(unsigned int vector)
{
+ struct msi_desc *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ entry = msi_desc[vector];
+ if (!entry || !entry->dev) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return 0;
+ }
+ entry->msi_attrib.state = 1; /* Mark it active */
+ spin_unlock_irqrestore(&msi_lock, flags);
+
return 0; /* never anything pending */
}
-static void pci_disable_msi(unsigned int vector);
+static void release_msi(unsigned int vector);
static void shutdown_msi_irq(unsigned int vector)
{
- pci_disable_msi(vector);
+ release_msi(vector);
}
#define shutdown_msi_irq_wo_maskbit shutdown_msi_irq
@@ -179,6 +187,18 @@
static unsigned int startup_msi_irq_w_maskbit(unsigned int vector)
{
+ struct msi_desc *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ entry = msi_desc[vector];
+ if (!entry || !entry->dev) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return 0;
+ }
+ entry->msi_attrib.state = 1; /* Mark it active */
+ spin_unlock_irqrestore(&msi_lock, flags);
+
unmask_MSI_irq(vector);
return 0; /* never anything pending */
}
@@ -200,7 +220,7 @@
* which implement the MSI-X Capability Structure.
*/
static struct hw_interrupt_type msix_irq_type = {
- .typename = "PCI MSI-X",
+ .typename = "PCI-MSI-X",
.startup = startup_msi_irq_w_maskbit,
.shutdown = shutdown_msi_irq_w_maskbit,
.enable = enable_msi_irq_w_maskbit,
@@ -216,7 +236,7 @@
* Mask-and-Pending Bits.
*/
static struct hw_interrupt_type msi_irq_w_maskbit_type = {
- .typename = "PCI MSI",
+ .typename = "PCI-MSI",
.startup = startup_msi_irq_w_maskbit,
.shutdown = shutdown_msi_irq_w_maskbit,
.enable = enable_msi_irq_w_maskbit,
@@ -232,7 +252,7 @@
* Mask-and-Pending Bits.
*/
static struct hw_interrupt_type msi_irq_wo_maskbit_type = {
- .typename = "PCI MSI",
+ .typename = "PCI-MSI",
.startup = startup_msi_irq_wo_maskbit,
.shutdown = shutdown_msi_irq_wo_maskbit,
.enable = enable_msi_irq_wo_maskbit,
@@ -265,6 +285,7 @@
msi_address->lo_address.value |= (MSI_TARGET_CPU << MSI_TARGET_CPU_SHIFT);
}
+static int msi_free_vector(struct pci_dev* dev, int vector, int reassign);
static int assign_msi_vector(void)
{
static int new_vector_avail = 1;
@@ -278,6 +299,8 @@
spin_lock_irqsave(&msi_lock, flags);
if (!new_vector_avail) {
+ int free_vector = 0;
+
/*
* vector_irq[] = -1 indicates that this specific vector is:
* - assigned for MSI (since MSI have no associated IRQ) or
@@ -294,13 +317,34 @@
for (vector = FIRST_DEVICE_VECTOR; vector < NR_IRQS; vector++) {
if (vector_irq[vector] != 0)
continue;
- vector_irq[vector] = -1;
- nr_released_vectors--;
- spin_unlock_irqrestore(&msi_lock, flags);
- return vector;
+ free_vector = vector;
+ if (!msi_desc[vector])
+ break;
+ else
+ continue;
}
+ if (!free_vector) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return -EBUSY;
+ }
+ vector_irq[free_vector] = -1;
+ nr_released_vectors--;
spin_unlock_irqrestore(&msi_lock, flags);
- return -EBUSY;
+ if (msi_desc[free_vector] != NULL) {
+ struct pci_dev *dev;
+ int tail;
+
+ /* free all linked vectors before re-assign */
+ do {
+ spin_lock_irqsave(&msi_lock, flags);
+ dev = msi_desc[free_vector]->dev;
+ tail = msi_desc[free_vector]->link.tail;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ msi_free_vector(dev, tail, 1);
+ } while (free_vector != tail);
+ }
+
+ return free_vector;
}
vector = assign_irq_vector(AUTO_ASSIGN);
last_alloc_vector = vector;
@@ -333,6 +377,15 @@
printk(KERN_INFO "WARNING: MSI INIT FAILURE\n");
return status;
}
+ last_alloc_vector = assign_irq_vector(AUTO_ASSIGN);
+ if (last_alloc_vector < 0) {
+ pci_msi_enable = 0;
+ printk(KERN_INFO "WARNING: ALL VECTORS ARE BUSY\n");
+ status = -EBUSY;
+ return status;
+ }
+ vector_irq[last_alloc_vector] = 0;
+ nr_released_vectors++;
printk(KERN_INFO "MSI INIT SUCCESS\n");
return status;
@@ -383,55 +436,49 @@
static void enable_msi_mode(struct pci_dev *dev, int pos, int type)
{
- u32 control;
+ u16 control;
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, &control);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
if (type == PCI_CAP_ID_MSI) {
/* Set enabled bits to single MSI & enable MSI_enable bit */
msi_enable(control, 1);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
} else {
msix_enable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
}
if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
/* PCI Express Endpoint device detected */
- u32 cmd;
- dev->bus->ops->read(dev->bus, dev->devfn, PCI_COMMAND, 2, &cmd);
+ u16 cmd;
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
cmd |= PCI_COMMAND_INTX_DISABLE;
- dev->bus->ops->write(dev->bus, dev->devfn, PCI_COMMAND, 2, cmd);
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
}
}
static void disable_msi_mode(struct pci_dev *dev, int pos, int type)
{
- u32 control;
+ u16 control;
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, &control);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
if (type == PCI_CAP_ID_MSI) {
/* Set enabled bits to single MSI & enable MSI_enable bit */
msi_disable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
} else {
msix_disable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
}
if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
/* PCI Express Endpoint device detected */
- u32 cmd;
- dev->bus->ops->read(dev->bus, dev->devfn, PCI_COMMAND, 2, &cmd);
+ u16 cmd;
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
cmd &= ~PCI_COMMAND_INTX_DISABLE;
- dev->bus->ops->write(dev->bus, dev->devfn, PCI_COMMAND, 2, cmd);
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
}
}
-static int msi_lookup_vector(struct pci_dev *dev)
+static int msi_lookup_vector(struct pci_dev *dev, int type)
{
int vector;
unsigned long flags;
@@ -439,11 +486,11 @@
spin_lock_irqsave(&msi_lock, flags);
for (vector = FIRST_DEVICE_VECTOR; vector < NR_IRQS; vector++) {
if (!msi_desc[vector] || msi_desc[vector]->dev != dev ||
- msi_desc[vector]->msi_attrib.entry_nr ||
+ msi_desc[vector]->msi_attrib.type != type ||
msi_desc[vector]->msi_attrib.default_vector != dev->irq)
- continue; /* not entry 0, skip */
+ continue;
spin_unlock_irqrestore(&msi_lock, flags);
- /* This pre-assigned entry-0 MSI vector for this device
+ /* This pre-assigned MSI vector for this device
already exits. Override dev->irq with this vector */
dev->irq = vector;
return 0;
@@ -458,10 +505,9 @@
if (!dev)
return;
- if (pci_find_capability(dev, PCI_CAP_ID_MSIX) > 0) {
- nr_reserved_vectors++;
+ if (pci_find_capability(dev, PCI_CAP_ID_MSIX) > 0)
nr_msix_devices++;
- } else if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0)
+ else if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0)
nr_reserved_vectors++;
}
@@ -480,22 +526,10 @@
struct msg_address address;
struct msg_data data;
int pos, vector;
- u32 control;
+ u16 control;
pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
- if (!pos)
- return -EINVAL;
-
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos),
- 2, &control);
- if (control & PCI_MSI_FLAGS_ENABLE)
- return 0;
-
- if (!msi_lookup_vector(dev)) {
- /* Lookup Sucess */
- enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
- return 0;
- }
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
/* MSI Entry Initialization */
if (!(entry = alloc_msi_entry()))
return -ENOMEM;
@@ -504,11 +538,14 @@
kmem_cache_free(msi_cachep, entry);
return -EBUSY;
}
+ entry->link.head = vector;
+ entry->link.tail = vector;
entry->msi_attrib.type = PCI_CAP_ID_MSI;
+ entry->msi_attrib.state = 0; /* Mark it not active */
entry->msi_attrib.entry_nr = 0;
entry->msi_attrib.maskbit = is_mask_bit_support(control);
- entry->msi_attrib.default_vector = dev->irq;
- dev->irq = vector; /* save default pre-assigned ioapic vector */
+ entry->msi_attrib.default_vector = dev->irq; /* Save IOAPIC IRQ */
+ dev->irq = vector;
entry->dev = dev;
if (is_mask_bit_support(control)) {
entry->mask_base = msi_mask_bits_reg(pos,
@@ -521,27 +558,27 @@
msi_data_init(&data, vector);
entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- dev->bus->ops->write(dev->bus, dev->devfn, msi_lower_address_reg(pos),
- 4, address.lo_address.value);
+ pci_write_config_dword(dev, msi_lower_address_reg(pos),
+ address.lo_address.value);
if (is_64bit_address(control)) {
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_upper_address_reg(pos), 4, address.hi_address);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_data_reg(pos, 1), 2, *((u32*)&data));
+ pci_write_config_dword(dev,
+ msi_upper_address_reg(pos), address.hi_address);
+ pci_write_config_word(dev,
+ msi_data_reg(pos, 1), *((u32*)&data));
} else
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_data_reg(pos, 0), 2, *((u32*)&data));
+ pci_write_config_word(dev,
+ msi_data_reg(pos, 0), *((u32*)&data));
if (entry->msi_attrib.maskbit) {
unsigned int maskbits, temp;
/* All MSIs are unmasked by default, Mask them all */
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_mask_bits_reg(pos, is_64bit_address(control)), 4,
+ pci_read_config_dword(dev,
+ msi_mask_bits_reg(pos, is_64bit_address(control)),
&maskbits);
temp = (1 << multi_msi_capable(control));
temp = ((temp - 1) & ~temp);
maskbits |= temp;
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_mask_bits_reg(pos, is_64bit_address(control)), 4,
+ pci_write_config_dword(dev,
+ msi_mask_bits_reg(pos, is_64bit_address(control)),
maskbits);
}
attach_msi_entry(entry, vector);
@@ -556,238 +593,219 @@
* @dev: pointer to the pci_dev data structure of MSI-X device function
*
* Setup the MSI-X capability structure of device funtion with a
- * single MSI-X vector. A return of zero indicates the successful setup
- * of an entry zero with the new MSI-X vector or non-zero for otherwise.
- * To request for additional MSI-X vectors, the device drivers are
- * required to utilize the following supported APIs:
- * 1) msi_alloc_vectors(...) for requesting one or more MSI-X vectors
- * 2) msi_free_vectors(...) for releasing one or more MSI-X vectors
- * back to PCI subsystem before calling free_irq(...)
+ * single MSI-X vector. A return of zero indicates the successful setup of
+ * requested MSI-X entries with allocated vectors or non-zero for otherwise.
**/
-static int msix_capability_init(struct pci_dev *dev)
+static int msix_capability_init(struct pci_dev *dev,
+ struct msix_entry *entries, int nvec)
{
- struct msi_desc *entry;
+ struct msi_desc *head = NULL, *tail = NULL, *entry = NULL;
struct msg_address address;
struct msg_data data;
- int vector = 0, pos, dev_msi_cap, i;
+ int vector, pos, i, j, nr_entries, temp = 0;
u32 phys_addr, table_offset;
- u32 control;
+ u16 control;
u8 bir;
void *base;
-
+
pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- if (!pos)
- return -EINVAL;
-
/* Request & Map MSI-X table region */
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2,
- &control);
- if (control & PCI_MSIX_FLAGS_ENABLE)
- return 0;
-
- if (!msi_lookup_vector(dev)) {
- /* Lookup Sucess */
- enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
- return 0;
- }
-
- dev_msi_cap = multi_msix_capable(control);
- dev->bus->ops->read(dev->bus, dev->devfn,
- msix_table_offset_reg(pos), 4, &table_offset);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ nr_entries = multi_msix_capable(control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
phys_addr = pci_resource_start (dev, bir);
phys_addr += (u32)(table_offset & ~PCI_MSIX_FLAGS_BIRMASK);
if (!request_mem_region(phys_addr,
- dev_msi_cap * PCI_MSIX_ENTRY_SIZE,
- "MSI-X iomap Failure"))
+ nr_entries * PCI_MSIX_ENTRY_SIZE,
+ "MSI-X vector table"))
return -ENOMEM;
- base = ioremap_nocache(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
- if (base == NULL)
- goto free_region;
- /* MSI Entry Initialization */
- entry = alloc_msi_entry();
- if (!entry)
- goto free_iomap;
- if ((vector = get_msi_vector(dev)) < 0)
- goto free_entry;
-
- entry->msi_attrib.type = PCI_CAP_ID_MSIX;
- entry->msi_attrib.entry_nr = 0;
- entry->msi_attrib.maskbit = 1;
- entry->msi_attrib.default_vector = dev->irq;
- dev->irq = vector; /* save default pre-assigned ioapic vector */
- entry->dev = dev;
- entry->mask_base = (unsigned long)base;
- /* Replace with MSI handler */
- irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
- /* Configure MSI-X capability structure */
- msi_address_init(&address);
- msi_data_init(&data, vector);
- entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
- MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- writel(address.lo_address.value, base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(address.hi_address, base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(*(u32*)&data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
- /* Initialize all entries from 1 up to 0 */
- for (i = 1; i < dev_msi_cap; i++) {
- writel(0, base + i * PCI_MSIX_ENTRY_SIZE +
+ base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
+ if (base == NULL) {
+ release_mem_region(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
+ return -ENOMEM;
+ }
+ /* MSI-X Table Initialization */
+ for (i = 0; i < nvec; i++) {
+ entry = alloc_msi_entry();
+ if (!entry)
+ break;
+ if ((vector = get_msi_vector(dev)) < 0)
+ break;
+
+ j = entries[i].entry;
+ entries[i].vector = vector;
+ entry->msi_attrib.type = PCI_CAP_ID_MSIX;
+ entry->msi_attrib.state = 0; /* Mark it not active */
+ entry->msi_attrib.entry_nr = j;
+ entry->msi_attrib.maskbit = 1;
+ entry->msi_attrib.default_vector = dev->irq;
+ entry->dev = dev;
+ entry->mask_base = (unsigned long)base;
+ if (!head) {
+ entry->link.head = vector;
+ entry->link.tail = vector;
+ head = entry;
+ } else {
+ entry->link.head = temp;
+ entry->link.tail = tail->link.tail;
+ tail->link.tail = vector;
+ head->link.head = vector;
+ }
+ temp = vector;
+ tail = entry;
+ /* Replace with MSI-X handler */
+ irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
+ /* Configure MSI-X capability structure */
+ msi_address_init(&address);
+ msi_data_init(&data, vector);
+ entry->msi_attrib.current_cpu =
+ ((address.lo_address.u.dest_id >>
+ MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
+ writel(address.lo_address.value,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(0, base + i * PCI_MSIX_ENTRY_SIZE +
+ writel(address.hi_address,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(0, base + i * PCI_MSIX_ENTRY_SIZE +
+ writel(*(u32*)&data,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_DATA_OFFSET);
+ attach_msi_entry(entry, vector);
}
- attach_msi_entry(entry, vector);
- /* Set MSI enabled bits */
+ if (i != nvec) {
+ i--;
+ for (; i >= 0; i--) {
+ vector = (entries + i)->vector;
+ msi_free_vector(dev, vector, 0);
+ (entries + i)->vector = 0;
+ }
+ return -EBUSY;
+ }
+ /* Set MSI-X enabled bits */
enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
-
+
return 0;
-
-free_entry:
- kmem_cache_free(msi_cachep, entry);
-free_iomap:
- iounmap(base);
-free_region:
- release_mem_region(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
-
- return ((vector < 0) ? -EBUSY : -ENOMEM);
}
/**
- * pci_enable_msi - configure device's MSI(X) capability structure
- * @dev: pointer to the pci_dev data structure of MSI(X) device function
+ * pci_enable_msi - configure device's MSI capability structure
+ * @dev: pointer to the pci_dev data structure of MSI device function
*
- * Setup the MSI/MSI-X capability structure of device function with
- * a single MSI(X) vector upon its software driver call to request for
- * MSI(X) mode enabled on its hardware device function. A return of zero
- * indicates the successful setup of an entry zero with the new MSI(X)
+ * Setup the MSI capability structure of device function with
+ * a single MSI vector upon its software driver call to request for
+ * MSI mode enabled on its hardware device function. A return of zero
+ * indicates the successful setup of an entry zero with the new MSI
* vector or non-zero for otherwise.
**/
int pci_enable_msi(struct pci_dev* dev)
{
- int status = -EINVAL;
+ int pos, temp = dev->irq, status = -EINVAL;
+ u16 control;
if (!pci_msi_enable || !dev)
return status;
- if (msi_init() < 0)
- return -ENOMEM;
+ if ((status = msi_init()) < 0)
+ return status;
- if ((status = msix_capability_init(dev)) == -EINVAL)
- status = msi_capability_init(dev);
- if (!status)
- nr_reserved_vectors--;
+ if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
+ return -EINVAL;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (control & PCI_MSI_FLAGS_ENABLE)
+ return 0; /* Already in MSI mode */
+
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ /* Lookup Sucess */
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ if (!vector_irq[dev->irq]) {
+ msi_desc[dev->irq]->msi_attrib.state = 0;
+ vector_irq[dev->irq] = -1;
+ nr_released_vectors--;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
+ return 0;
+ }
+ spin_unlock_irqrestore(&msi_lock, flags);
+ dev->irq = temp;
+ }
+ /* Check whether driver already requested for MSI-X vectors */
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ printk(KERN_INFO "Can't enable MSI. Device already had MSI-X vectors assigned\n");
+ dev->irq = temp;
+ return -EINVAL;
+ }
+ status = msi_capability_init(dev);
+ if (!status) {
+ if (!pos)
+ nr_reserved_vectors--; /* Only MSI capable */
+ else if (nr_msix_devices > 0)
+ nr_msix_devices--; /* Both MSI and MSI-X capable,
+ but choose enabling MSI */
+ }
return status;
}
-static int msi_free_vector(struct pci_dev* dev, int vector);
-static void pci_disable_msi(unsigned int vector)
+void pci_disable_msi(struct pci_dev* dev)
{
- int head, tail, type, default_vector;
struct msi_desc *entry;
- struct pci_dev *dev;
+ int pos, default_vector;
+ u16 control;
unsigned long flags;
+ if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
+ return;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (!(control & PCI_MSI_FLAGS_ENABLE))
+ return;
+
spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[vector];
- if (!entry || !entry->dev) {
+ entry = msi_desc[dev->irq];
+ if (!entry || !entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI) {
spin_unlock_irqrestore(&msi_lock, flags);
return;
}
- dev = entry->dev;
- type = entry->msi_attrib.type;
- head = entry->link.head;
- tail = entry->link.tail;
- default_vector = entry->msi_attrib.default_vector;
- spin_unlock_irqrestore(&msi_lock, flags);
-
- disable_msi_mode(dev, pci_find_capability(dev, type), type);
- /* Restore dev->irq to its default pin-assertion vector */
- dev->irq = default_vector;
- if (type == PCI_CAP_ID_MSIX && head != tail) {
- /* Bad driver, which do not call msi_free_vectors before exit.
- We must do a cleanup here */
- while (1) {
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[vector];
- head = entry->link.head;
- tail = entry->link.tail;
- spin_unlock_irqrestore(&msi_lock, flags);
- if (tail == head)
- break;
- if (msi_free_vector(dev, entry->link.tail))
- break;
- }
+ if (entry->msi_attrib.state) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on vector->%d\n",
+ dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn),
+ dev->irq);
+ BUG_ON(entry->msi_attrib.state > 0);
+ } else {
+ vector_irq[dev->irq] = 0; /* free it */
+ nr_released_vectors++;
+ default_vector = entry->msi_attrib.default_vector;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ /* Restore dev->irq to its default pin-assertion vector */
+ dev->irq = default_vector;
+ disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
+ PCI_CAP_ID_MSI);
}
}
-static int msi_alloc_vector(struct pci_dev* dev, int head)
+static void release_msi(unsigned int vector)
{
struct msi_desc *entry;
- struct msg_address address;
- struct msg_data data;
- int i, offset, pos, dev_msi_cap, vector;
- u32 low_address, control;
- unsigned long base = 0L;
unsigned long flags;
spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry) {
- spin_unlock_irqrestore(&msi_lock, flags);
- return -EINVAL;
- }
- base = entry->mask_base;
+ entry = msi_desc[vector];
+ if (entry && entry->dev)
+ entry->msi_attrib.state = 0; /* Mark it not active */
spin_unlock_irqrestore(&msi_lock, flags);
-
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos),
- 2, &control);
- dev_msi_cap = multi_msix_capable(control);
- for (i = 1; i < dev_msi_cap; i++) {
- if (!(low_address = readl(base + i * PCI_MSIX_ENTRY_SIZE)))
- break;
- }
- if (i >= dev_msi_cap)
- return -EINVAL;
-
- /* MSI Entry Initialization */
- if (!(entry = alloc_msi_entry()))
- return -ENOMEM;
-
- if ((vector = get_new_vector()) < 0) {
- kmem_cache_free(msi_cachep, entry);
- return vector;
- }
- entry->msi_attrib.type = PCI_CAP_ID_MSIX;
- entry->msi_attrib.entry_nr = i;
- entry->msi_attrib.maskbit = 1;
- entry->dev = dev;
- entry->link.head = head;
- entry->mask_base = base;
- irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
- /* Configure MSI-X capability structure */
- msi_address_init(&address);
- msi_data_init(&data, vector);
- entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
- MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
- writel(address.lo_address.value, base + offset +
- PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(address.hi_address, base + offset +
- PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(*(u32*)&data, base + offset + PCI_MSIX_ENTRY_DATA_OFFSET);
- writel(1, base + offset + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- attach_msi_entry(entry, vector);
-
- return vector;
}
-static int msi_free_vector(struct pci_dev* dev, int vector)
+static int msi_free_vector(struct pci_dev* dev, int vector, int reassign)
{
struct msi_desc *entry;
- int entry_nr, type;
+ int head, entry_nr, type;
unsigned long base = 0L;
unsigned long flags;
@@ -799,66 +817,177 @@
}
type = entry->msi_attrib.type;
entry_nr = entry->msi_attrib.entry_nr;
+ head = entry->link.head;
base = entry->mask_base;
- if (entry->link.tail != entry->link.head) {
- msi_desc[entry->link.head]->link.tail = entry->link.tail;
- if (entry->link.tail)
- msi_desc[entry->link.tail]->link.head = entry->link.head;
- }
+ msi_desc[entry->link.head]->link.tail = entry->link.tail;
+ msi_desc[entry->link.tail]->link.head = entry->link.head;
entry->dev = NULL;
- vector_irq[vector] = 0;
- nr_released_vectors++;
+ if (!reassign) {
+ vector_irq[vector] = 0;
+ nr_released_vectors++;
+ }
msi_desc[vector] = NULL;
spin_unlock_irqrestore(&msi_lock, flags);
kmem_cache_free(msi_cachep, entry);
- if (type == PCI_CAP_ID_MSIX) {
- int offset;
- offset = entry_nr * PCI_MSIX_ENTRY_SIZE;
- writel(1, base + offset + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- writel(0, base + offset + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+ if (type == PCI_CAP_ID_MSIX) {
+ if (!reassign)
+ writel(1, base +
+ entry_nr * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
+
+ if (head == vector) {
+ /*
+ * Detect last MSI-X vector to be released.
+ * Release the MSI-X memory-mapped table.
+ */
+ int pos, nr_entries;
+ u32 phys_addr, table_offset;
+ u16 control;
+ u8 bir;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+ pci_read_config_word(dev, msi_control_reg(pos),
+ &control);
+ nr_entries = multi_msix_capable(control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
+ bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
+ phys_addr = pci_resource_start (dev, bir);
+ phys_addr += (u32)(table_offset &
+ ~PCI_MSIX_FLAGS_BIRMASK);
+ iounmap((void*)base);
+ release_mem_region(phys_addr,
+ nr_entries * PCI_MSIX_ENTRY_SIZE);
+ }
}
return 0;
}
+static int reroute_msix_table(int head, struct msix_entry *entries, int *nvec)
+{
+ int vector = head, tail = 0;
+ int i = 0, j = 0, nr_entries = 0;
+ unsigned long base = 0L;
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ while (head != tail) {
+ nr_entries++;
+ tail = msi_desc[vector]->link.tail;
+ if (entries[0].entry == msi_desc[vector]->msi_attrib.entry_nr)
+ j = vector;
+ vector = tail;
+ }
+ if (*nvec > nr_entries) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ *nvec = nr_entries;
+ return -EINVAL;
+ }
+ vector = ((j > 0) ? j : head);
+ for (i = 0; i < *nvec; i++) {
+ j = msi_desc[vector]->msi_attrib.entry_nr;
+ msi_desc[vector]->msi_attrib.state = 0; /* Mark it not active */
+ vector_irq[vector] = -1; /* Mark it busy */
+ nr_released_vectors--;
+ entries[i].vector = vector;
+ if (j != (entries + i)->entry) {
+ base = msi_desc[vector]->mask_base;
+ msi_desc[vector]->msi_attrib.entry_nr =
+ (entries + i)->entry;
+ writel( readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET), base +
+ (entries + i)->entry * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+ writel( readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET), base +
+ (entries + i)->entry * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+ writel( (readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_DATA_OFFSET) & 0xff00) | vector,
+ base + (entries+i)->entry*PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_DATA_OFFSET);
+ }
+ vector = msi_desc[vector]->link.tail;
+ }
+ spin_unlock_irqrestore(&msi_lock, flags);
+
+ return 0;
+}
+
/**
- * msi_alloc_vectors - allocate additional MSI-X vectors
+ * pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
- * @vector: pointer to an array of new allocated MSI-X vectors
+ * @data: pointer to an array of MSI-X entries
* @nvec: number of MSI-X vectors requested for allocation by device driver
*
- * Allocate additional MSI-X vectors requested by device driver. A
- * return of zero indicates the successful setup of MSI-X capability
- * structure with new allocated MSI-X vectors or non-zero for otherwise.
+ * Setup the MSI-X capability structure of device function with the number
+ * of requested vectors upon its software driver call to request for
+ * MSI-X mode enabled on its hardware device function. A return of zero
+ * indicates the successful configuration of MSI-X capability structure
+ * with new allocated MSI-X vectors. A return of < 0 indicates a failure.
+ * Or a return of > 0 indicates that driver request is exceeding the number
+ * of vectors available. Driver should use the returned value to re-send
+ * its request.
**/
-int msi_alloc_vectors(struct pci_dev* dev, int *vector, int nvec)
+int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
{
- struct msi_desc *entry;
- int i, head, pos, vec, free_vectors, alloc_vectors;
- int *vectors = (int *)vector;
- u32 control;
+ int status, pos, nr_entries, free_vectors;
+ int i, j, temp;
+ u16 control;
unsigned long flags;
- if (!pci_msi_enable || !dev)
+ if (!pci_msi_enable || !dev || !entries)
return -EINVAL;
-
+
+ if ((status = msi_init()) < 0)
+ return status;
+
if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
return -EINVAL;
-
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2, &control);
- if (nvec > multi_msix_capable(control))
- return -EINVAL;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev || /* legal call */
- entry->msi_attrib.type != PCI_CAP_ID_MSIX || /* must be MSI-X */
- entry->link.head != entry->link.tail) { /* already multi */
- spin_unlock_irqrestore(&msi_lock, flags);
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (control & PCI_MSIX_FLAGS_ENABLE)
+ return -EINVAL; /* Already in MSI-X mode */
+
+ nr_entries = multi_msix_capable(control);
+ if (nvec > nr_entries)
return -EINVAL;
+
+ /* Check for any invalid entries */
+ for (i = 0; i < nvec; i++) {
+ if (entries[i].entry >= nr_entries)
+ return -EINVAL; /* invalid entry */
+ for (j = i + 1; j < nvec; j++) {
+ if (entries[i].entry == entries[j].entry)
+ return -EINVAL; /* duplicate entry */
+ }
+ }
+ temp = dev->irq;
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ /* Lookup Sucess */
+ nr_entries = nvec;
+ /* Reroute MSI-X table */
+ if (reroute_msix_table(dev->irq, entries, &nr_entries)) {
+ /* #requested > #previous-assigned */
+ dev->irq = temp;
+ return nr_entries;
+ }
+ dev->irq = temp;
+ enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
+ return 0;
+ }
+ /* Check whether driver already requested for MSI vector */
+ if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ printk(KERN_INFO "Can't enable MSI-X. Device already had MSI vector assigned\n");
+ dev->irq = temp;
+ return -EINVAL;
}
+
+ spin_lock_irqsave(&msi_lock, flags);
/*
* msi_lock is provided to ensure that enough vectors resources are
* available before granting.
@@ -874,71 +1003,65 @@
free_vectors /= nr_msix_devices;
spin_unlock_irqrestore(&msi_lock, flags);
- if (nvec > free_vectors)
- return -EBUSY;
+ if (nvec > free_vectors) {
+ if (free_vectors > 0)
+ return free_vectors;
+ else
+ return -EBUSY;
+ }
- alloc_vectors = 0;
- head = dev->irq;
- for (i = 0; i < nvec; i++) {
- if ((vec = msi_alloc_vector(dev, head)) < 0)
- break;
- *(vectors + i) = vec;
- head = vec;
- alloc_vectors++;
- }
- if (alloc_vectors != nvec) {
- for (i = 0; i < alloc_vectors; i++) {
- vec = *(vectors + i);
- msi_free_vector(dev, vec);
- }
- spin_lock_irqsave(&msi_lock, flags);
- msi_desc[dev->irq]->link.tail = msi_desc[dev->irq]->link.head;
- spin_unlock_irqrestore(&msi_lock, flags);
- return -EBUSY;
- }
- if (nr_msix_devices > 0)
+ status = msix_capability_init(dev, entries, nvec);
+ if (!status && nr_msix_devices > 0)
nr_msix_devices--;
-
- return 0;
+
+ return status;
}
-/**
- * msi_free_vectors - reclaim MSI-X vectors to unused state
- * @dev: pointer to the pci_dev data structure of MSI-X device function
- * @vector: pointer to an array of released MSI-X vectors
- * @nvec: number of MSI-X vectors requested for release by device driver
- *
- * Reclaim MSI-X vectors released by device driver to unused state,
- * which may be used later on. A return of zero indicates the
- * success or non-zero for otherwise. Device driver should call this
- * before calling function free_irq.
- **/
-int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec)
+void pci_disable_msix(struct pci_dev* dev)
{
- struct msi_desc *entry;
- int i;
- unsigned long flags;
+ int pos, temp;
+ u16 control;
+
+ if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
+ return;
- if (!pci_msi_enable)
- return -EINVAL;
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (!(control & PCI_MSIX_FLAGS_ENABLE))
+ return;
+
+ temp = dev->irq;
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ int state, vector, head, tail = 0, warning = 0;
+ unsigned long flags;
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev ||
- entry->msi_attrib.type != PCI_CAP_ID_MSIX ||
- entry->link.head == entry->link.tail) { /* Nothing to free */
+ vector = head = dev->irq;
+ spin_lock_irqsave(&msi_lock, flags);
+ while (head != tail) {
+ state = msi_desc[vector]->msi_attrib.state;
+ if (state)
+ warning = 1;
+ else {
+ vector_irq[vector] = 0; /* free it */
+ nr_released_vectors++;
+ }
+ tail = msi_desc[vector]->link.tail;
+ vector = tail;
+ }
spin_unlock_irqrestore(&msi_lock, flags);
- return -EINVAL;
- }
- spin_unlock_irqrestore(&msi_lock, flags);
+ if (warning) {
+ dev->irq = temp;
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on all vectors\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn));
+ BUG_ON(warning > 0);
+ } else {
+ dev->irq = temp;
+ disable_msi_mode(dev,
+ pci_find_capability(dev, PCI_CAP_ID_MSIX),
+ PCI_CAP_ID_MSIX);
- for (i = 0; i < nvec; i++) {
- if (*(vector + i) == dev->irq)
- continue;/* Don't free entry 0 if mistaken by driver */
- msi_free_vector(dev, *(vector + i));
+ }
}
-
- return 0;
}
/**
@@ -952,62 +1075,73 @@
**/
void msi_remove_pci_irq_vectors(struct pci_dev* dev)
{
- struct msi_desc *entry;
- int type, temp;
+ int state, pos, temp;
unsigned long flags;
-
+
if (!pci_msi_enable || !dev)
return;
-
- if (!pci_find_capability(dev, PCI_CAP_ID_MSI)) {
- if (!pci_find_capability(dev, PCI_CAP_ID_MSIX))
- return;
- }
- temp = dev->irq;
- if (msi_lookup_vector(dev))
- return;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev) {
+
+ temp = dev->irq; /* Save IOAPIC IRQ */
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSI)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ spin_lock_irqsave(&msi_lock, flags);
+ state = msi_desc[dev->irq]->msi_attrib.state;
spin_unlock_irqrestore(&msi_lock, flags);
- return;
- }
- type = entry->msi_attrib.type;
- spin_unlock_irqrestore(&msi_lock, flags);
-
- msi_free_vector(dev, dev->irq);
- if (type == PCI_CAP_ID_MSIX) {
- int i, pos, dev_msi_cap;
- u32 phys_addr, table_offset;
- u32 control;
- u8 bir;
-
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2, &control);
- dev_msi_cap = multi_msix_capable(control);
- dev->bus->ops->read(dev->bus, dev->devfn,
- msix_table_offset_reg(pos), 4, &table_offset);
- bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
- phys_addr = pci_resource_start (dev, bir);
- phys_addr += (u32)(table_offset & ~PCI_MSIX_FLAGS_BIRMASK);
- for (i = FIRST_DEVICE_VECTOR; i < NR_IRQS; i++) {
+ if (state) {
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on vector->%d\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn), dev->irq);
+ BUG_ON(state > 0);
+ } else /* Release MSI vector assigned to this device */
+ msi_free_vector(dev, dev->irq, 0);
+ dev->irq = temp; /* Restore IOAPIC IRQ */
+ }
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ int vector, head, tail = 0, warning = 0;
+ unsigned long base = 0L;
+
+ vector = head = dev->irq;
+ while (head != tail) {
spin_lock_irqsave(&msi_lock, flags);
- if (!msi_desc[i] || msi_desc[i]->dev != dev) {
- spin_unlock_irqrestore(&msi_lock, flags);
- continue;
- }
+ state = msi_desc[vector]->msi_attrib.state;
+ tail = msi_desc[vector]->link.tail;
+ base = msi_desc[vector]->mask_base;
spin_unlock_irqrestore(&msi_lock, flags);
- msi_free_vector(dev, i);
+ if (state)
+ warning = 1;
+ else if (vector != head) /* Release MSI-X vector */
+ msi_free_vector(dev, vector, 0);
+ vector = tail;
+ }
+ msi_free_vector(dev, vector, 0);
+ if (warning) {
+ /* Force to release the MSI-X memory-mapped table */
+ u32 phys_addr, table_offset;
+ u16 control;
+ u8 bir;
+
+ pci_read_config_word(dev, msi_control_reg(pos),
+ &control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
+ bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
+ phys_addr = pci_resource_start (dev, bir);
+ phys_addr += (u32)(table_offset &
+ ~PCI_MSIX_FLAGS_BIRMASK);
+ iounmap((void*)base);
+ release_mem_region(phys_addr, PCI_MSIX_ENTRY_SIZE *
+ multi_msix_capable(control));
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on all vectors\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn));
+ BUG_ON(warning > 0);
}
- writel(1, entry->mask_base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- iounmap((void*)entry->mask_base);
- release_mem_region(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
+ dev->irq = temp; /* Restore IOAPIC IRQ */
}
- dev->irq = temp;
- nr_reserved_vectors++;
}
EXPORT_SYMBOL(pci_enable_msi);
-EXPORT_SYMBOL(msi_alloc_vectors);
-EXPORT_SYMBOL(msi_free_vectors);
+EXPORT_SYMBOL(pci_disable_msi);
+EXPORT_SYMBOL(pci_enable_msix);
+EXPORT_SYMBOL(pci_disable_msix);
Index: linux-bk/drivers/pci/msi.h
===================================================================
--- linux-bk.orig/drivers/pci/msi.h
+++ linux-bk/drivers/pci/msi.h
@@ -140,7 +140,8 @@
struct {
__u8 type : 5; /* {0: unused, 5h:MSI, 11h:MSI-X} */
__u8 maskbit : 1; /* mask-pending bit supported ? */
- __u8 reserved: 2; /* reserved */
+ __u8 state : 1; /* {0: free, 1: busy} */
+ __u8 reserved: 1; /* reserved */
__u8 entry_nr; /* specific enabled entry */
__u8 default_vector; /* default pre-assigned vector */
__u8 current_cpu; /* current destination cpu */
Index: linux-bk/include/linux/pci.h
===================================================================
--- linux-bk.orig/include/linux/pci.h
+++ linux-bk/include/linux/pci.h
@@ -831,16 +831,27 @@
extern struct pci_dev *isa_bridge;
#endif
+struct msix_entry {
+ u16 vector; /* kernel uses to write allocated vector */
+ u16 entry; /* driver uses to specify entry, OS writes */
+};
+
#ifndef CONFIG_PCI_USE_VECTOR
static inline void pci_scan_msi_device(struct pci_dev *dev) {}
static inline int pci_enable_msi(struct pci_dev *dev) {return -1;}
+static inline void pci_disable_msi(struct pci_dev *dev) {}
+static inline int pci_enable_msix(struct pci_dev* dev,
+ struct msix_entry *entries, int nvec) {return -1;}
+static inline void pci_disable_msix(struct pci_dev *dev) {}
static inline void msi_remove_pci_irq_vectors(struct pci_dev *dev) {}
#else
extern void pci_scan_msi_device(struct pci_dev *dev);
extern int pci_enable_msi(struct pci_dev *dev);
+extern void pci_disable_msi(struct pci_dev *dev);
+extern int pci_enable_msix(struct pci_dev* dev,
+ struct msix_entry *entries, int nvec);
+extern void pci_disable_msix(struct pci_dev *dev);
extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
-extern int msi_alloc_vectors(struct pci_dev* dev, int *vector, int nvec);
-extern int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec);
#endif
#endif /* CONFIG_PCI */
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE:[PATCH]2.6.7 MSI-X Update
@ 2004-06-26 1:21 long
0 siblings, 0 replies; 4+ messages in thread
From: long @ 2004-06-26 1:21 UTC (permalink / raw)
To: linux-kernel, roland; +Cc: ak, akpm, greg, jgazik, tom.l.nguyen, zwane
Hi Roland,
Attach is an update on previous MSI-X patch. This update reflects lkml
comments on the code as well as suggestion of two additional APIs
(pci_disable_msi and pci_disable_msix). Please test it out and let me
know what you think.
Starting on 06/26, I'll not have access to email for two weeks. I'll
respond to any inputs after that.
Thanks,
Long
----------------------------------------------------------------------
diff -urN linux-2.6.7/Documentation/MSI-HOWTO.txt patch-2.6.7-fix-msix/Documentation/MSI-HOWTO.txt
--- linux-2.6.7/Documentation/MSI-HOWTO.txt 2004-05-09 22:31:58.000000000 -0400
+++ patch-2.6.7-fix-msix/Documentation/MSI-HOWTO.txt 2004-06-25 16:10:58.000000000 -0400
@@ -3,13 +3,14 @@
10/03/2003
Revised Feb 12, 2004 by Martine Silbermann
email: Martine.Silbermann@hp.com
+ Revised Jun 25, 2004 by Tom L Nguyen
1. About this guide
-This guide describes the basics of Message Signaled Interrupts(MSI), the
-advantages of using MSI over traditional interrupt mechanisms, and how
-to enable your driver to use MSI or MSI-X. Also included is a Frequently
-Asked Questions.
+This guide describes the basics of Message Signaled Interrupts (MSI),
+the advantages of using MSI over traditional interrupt mechanisms,
+and how to enable your driver to use MSI or MSI-X. Also included is
+a Frequently Asked Questions.
2. Copyright 2003 Intel Corporation
@@ -35,7 +36,7 @@
the MSI/MSI-X capability structure in its PCI capability list. The
device function may implement both the MSI capability structure and
the MSI-X capability structure; however, the bus driver should not
-enable both, but instead enable only the MSI-X capability structure.
+enable both.
The MSI capability structure contains Message Control register,
Message Address register and Message Data register. These registers
@@ -86,7 +87,7 @@
support for better interrupt performance.
Using MSI enables the device functions to support two or more
-vectors, which can be configure to target different CPU's to
+vectors, which can be configured to target different CPU's to
increase scalability.
5. Configuring a driver to use MSI/MSI-X
@@ -95,26 +96,49 @@
support this capability. The CONFIG_PCI_USE_VECTOR kernel option
must be selected to enable MSI/MSI-X support.
-5.1 Including MSI support into the kernel
+5.1 Including MSI/MSI-X support into the kernel
-To allow MSI-Capable device drivers to selectively enable MSI (using
-pci_enable_msi as described below), the VECTOR based scheme needs to
-be enabled by setting CONFIG_PCI_USE_VECTOR.
+To allow MSI/MSI-X capable device drivers to selectively enable
+MSI/MSI-X (using pci_enable_msi()/pci_enable_msix() as described
+below), the VECTOR based scheme needs to be enabled by setting
+CONFIG_PCI_USE_VECTOR during kernel config.
Since the target of the inbound message is the local APIC, providing
-CONFIG_PCI_USE_VECTOR is dependent on whether CONFIG_X86_LOCAL_APIC
-is enabled or not.
+CONFIG_X86_LOCAL_APIC must be enabled as well as CONFIG_PCI_USE_VECTOR.
-int pci_enable_msi(struct pci_dev *)
+5.2 Configuring for MSI support
+
+Due to the non-contiguous fashion in vector assignment of the
+existing Linux kernel, this version does not support multiple
+messages regardless of a device function is capable of supporting
+more than one vector. To enable MSI on a device function's MSI
+capability structure requires a device driver to call the function
+pci_enable_msi() explicitly.
+
+5.2.1 API pci_enable_msi
+
+int pci_enable_msi(struct pci_dev *dev)
With this new API, any existing device driver, which like to have
-MSI enabled on its device function, must call this explicitly. A
-successful call will initialize the MSI/MSI-X capability structure
-with ONE vector, regardless of whether the device function is
+MSI enabled on its device function, must call this API to enable MSI
+A successful call will initialize the MSI capability structure
+with ONE vector, regardless of whether a device function is
capable of supporting multiple messages. This vector replaces the
pre-assigned dev->irq with a new MSI vector. To avoid the conflict
of new assigned vector with existing pre-assigned vector requires
-the device driver to call this API before calling request_irq(...).
+a device driver to call this API before calling request_irq().
+
+5.2.2 API pci_disable_msi
+
+void pci_disable_msi(struct pci_dev *dev)
+
+This API is needed to encounter the case where a device driver is
+unloaded without doing request_irq on assigned MSI vector results
+a device being left in MSI mode and not be able to recover without
+rebooting. This API provides a device driver an ability to recover
+and resolves vector leakage.
+
+5.2.3 MSI mode vs. legacy mode diagram
The below diagram shows the events, which switches the interrupt
mode on the MSI-capable device function between MSI mode and
@@ -124,105 +148,258 @@
| | <=============== | |
| MSI MODE | | PIN-IRQ ASSERTION MODE |
| | ===============> | |
- ------------ free_irq ------------------------
+ ------------ free_irq/ ------------------------
+ pci_disable_msi
-5.2 Configuring for MSI support
-Due to the non-contiguous fashion in vector assignment of the
-existing Linux kernel, this version does not support multiple
-messages regardless of the device function is capable of supporting
-more than one vector. The bus driver initializes only entry 0 of
-this capability if pci_enable_msi(...) is called successfully by
-the device driver.
+Figure 1.0 MSI Mode vs. Legacy Mode
+
+In Figure 1.0, a device operates by default in legacy mode. Legacy
+in this context means PCI pin-irq assertion or PCI-Express INTx
+emulation. A successful MSI request (using pci_enable_msi()) switches
+a device's interrupt mode to MSI mode. A pre-assigned IOAPIC vector
+stored in dev->irq will be saved by the PCI subsystem and a new
+assigned MSI vector will replace dev->irq.
+
+To return back to its default mode, a device driver must call
+free_irq() using the allocated MSI vector. The PCI subsystem restores a
+device's dev->irq with a pre-assigned IOAPIC vector and marks released
+MSI vector as unused. Once being marked as unused, there is no
+guarantee that the PCI subsystem will reserve this MSI vector for a
+device. Depending on the availability of current PCI vector resources
+and the number of MSI/MSI-X requests from other drivers, this MSI
+may be re-assigned. For the case where the PCI subsystem re-assigned
+this MSI vector another driver, a request to switching back to MSI
+mode may result in being assigned a different MSI vector or a failure
+if no more vectors are available.
5.3 Configuring for MSI-X support
-Both the MSI capability structure and the MSI-X capability structure
-share the same above semantics; however, due to the ability of the
-system software to configure each vector of the MSI-X capability
-structure with an independent message address and message data, the
-non-contiguous fashion in vector assignment of the existing Linux
-kernel has no impact on supporting multiple messages on an MSI-X
-capable device functions. By default, as mentioned above, ONE vector
-should be always allocated to the MSI-X capability structure at
-entry 0. The bus driver does not initialize other entries of the
-MSI-X table.
-
-Note that the PCI subsystem should have full control of a MSI-X
-table that resides in Memory Space. The software device driver
-should not access this table.
-
-To request for additional vectors, the device software driver should
-call function msi_alloc_vectors(). It is recommended that the
-software driver should call this function once during the
+Due to the ability of the system software to configure each vector of
+the MSI-X capability structure with an independent message address
+and message data, the non-contiguous fashion in vector assignment of
+the existing Linux kernel has no impact on supporting multiple
+messages on an MSI-X capable device functions. To enable MSI-X on
+a device function's MSI-X capability structure requires its device
+driver to call the function pci_enable_msix() explicitly.
+
+The function pci_enable_msix(), once invoked, enables either
+all or nothing, depending on the current availability of PCI vector
+resources. If the PCI vector resources are available for the number
+of vectors requested by a device driver, this function will configure
+the MSI-X table of the MSI-X capability structure of a device with
+requested messages. To emphasize this reason, for example, a device
+may be capable for supporting the maximum of 32 vectors while its
+software driver usually may request 4 vectors. It is recommended
+that the device driver should call this function once during the
initialization phase of the device driver.
-The function msi_alloc_vectors(), once invoked, enables either
-all or nothing, depending on the current availability of vector
-resources. If no vector resources are available, the device function
-still works with ONE vector. If the vector resources are available
-for the number of vectors requested by the driver, this function
-will reconfigure the MSI-X capability structure of the device with
-additional messages, starting from entry 1. To emphasize this
-reason, for example, the device may be capable for supporting the
-maximum of 32 vectors while its software driver usually may request
-4 vectors.
-
-For each vector, after this successful call, the device driver is
-responsible to call other functions like request_irq(), enable_irq(),
-etc. to enable this vector with its corresponding interrupt service
-handler. It is the device driver's choice to have all vectors shared
-the same interrupt service handler or each vector with a unique
-interrupt service handler.
-
-In addition to the function msi_alloc_vectors(), another function
-msi_free_vectors() is provided to allow the software driver to
-release a number of vectors back to the vector resources. Once
-invoked, the PCI subsystem disables (masks) each vector released.
-These vectors are no longer valid for the hardware device and its
-software driver to use. Like free_irq, it recommends that the
-device driver should also call msi_free_vectors to release all
-additional vectors previously requested.
-
-int msi_alloc_vectors(struct pci_dev *dev, int *vector, int nvec)
-
-This API enables the software driver to request the PCI subsystem
-for additional messages. Depending on the number of vectors
-available, the PCI subsystem enables either all or nothing.
+Unlike the function pci_enable_msi(), the function pci_enable_msix()
+does not replace the pre-assigned IOAPIC dev->irq with a new MSI
+vector because the PCI subsystem writes the 1:1 vector-to-entry mapping
+into the field vector of each element contained in a second argument.
+Note that the pre-assigned IO-APIC dev->irq is valid only if the device
+operates in PIN-IRQ assertion mode. In MSI-X mode, any attempt of
+using dev->irq by the device driver to request for interrupt service
+may result unpredictabe behavior.
+
+For each MSI-X vector granted, a device driver is responsible to call
+other functions like request_irq(), enable_irq(), etc. to enable
+this vector with its corresponding interrupt service handler. It is
+a device driver's choice to assign all vectors with the same
+interrupt service handler or each vector with a unique interrupt
+service handler.
+
+5.3.1 Handling MMIO address space of MSI-X Table
+
+The PCI 3.0 specification has implementation notes that MMIO address
+space for a device's MSI-X structure should be isolated so that the
+software system can set different page for controlling accesses to
+the MSI-X structure. The implementation of MSI patch requires the PCI
+subsystem, not a device driver, to maintain full control of the MSI-X
+table/MSI-X PBA and MMIO address space of the MSI-X table/MSI-X PBA.
+A device driver is prohibited from requesting the MMIO address space
+of the MSI-X table/MSI-X PBA. Otherwise, the PCI subsystem will fail
+enabling MSI-X on its hardware device when it calls the function
+pci_enable_msix().
+
+5.3.2 Handling MSI-X allocation
+
+Determining the number of MSI-X vectors allocated to a function is
+dependent on the number of MSI capable devices and MSI-X capable
+devices populated in the system. The policy of allocating MSI-X
+vectors to a function is defined as the following:
+
+#of MSI-X vectors allocated to a function = (x - y)/z where
+
+x = The number of available PCI vector resources by the time
+ the device driver calls pci_enable_msix(). The PCI vector
+ resources is the sum of the number of unassigned vectors
+ (new) and the number of released vectors when any MSI/MSI-X
+ device driver switches its hardware device back to a legacy
+ mode or is hot-removed. The number of unassigned vectors
+ may exclude some vectors reserved, as defined in parameter
+ NR_HP_RESERVED_VECTORS, for the case where the system is
+ capable of supporting hot-add/hot-remove operations. Users
+ may change the value defined in NR_HR_RESERVED_VECTORS to
+ meet their specific needs.
+
+y = The number of MSI capable devices populated in the system.
+ This policy ensures that each MSI capable device has its
+ vector reserved to avoid the case where some MSI-X capable
+ drivers may attempt to claim all available vector resources.
+
+z = The number of MSI-X capable devices pupulated in the system.
+ This policy ensures that maximum (x - y) is distributed
+ evenly among MSI-X capable devices.
+
+Note that the PCI subsystem scans y and z during a bus enumeration.
+When the PCI subsystem completes configuring MSI/MSI-X capability
+structure of a device as requested by its device driver, y/z is
+decremented accordingly.
+
+5.3.3 Handling MSI-X shortages
+
+For the case where fewer MSI-X vectors are allocated to a function
+than requested, the function pci_enable_msix() will return the
+maximum number of MSI-X vectors available to the caller. A device
+driver may re-send its request with fewer or equal vectors indicated
+in a return. For example, if a device driver requests 5 vectors, but
+the number of available vectors is 3 vectors, a value of 3 will be a
+return as a result of pci_enable_msix() call. A function could be
+designed for its driver to use only 3 MSI-X table entries as
+different combinations as ABC--, A-B-C, A--CB, etc. Note that this
+patch does not support multiple entries with the same vector. Such
+attempt by a device driver to use 5 MSI-X table entries with 3 vectors
+as ABBCC, AABCC, BCCBA, etc will result as a failure by the function
+pci_enable_msix(). Below are the reasons why supporting multiple
+entries with the same vector is an undesirable solution.
+
+ - The PCI subsystem can not determine which entry, which
+ generated the message, to mask/unmask MSI while handling
+ software driver ISR. Attempting to walk through all MSI-X
+ table entries (2048 max) to mask/unmask any match vector
+ is an undesirable solution.
+
+ - Walk through all MSI-X table entries (2048 max) to handle
+ SMP affinity of any match vector is an undesirable solution.
+
+5.3.4 API pci_enable_msix
+
+int pci_enable_msix(struct pci_dev *dev, u32 *entries, int nvec)
+
+This API enables a device driver to request the PCI subsystem
+for enabling MSI-X messages on its hardware device. Depending on
+the availability of PCI vectors resources, the PCI subsystem enables
+either all or nothing.
Argument dev points to the device (pci_dev) structure.
-Argument vector is a pointer of integer type. The number of
-elements is indicated in argument nvec.
+
+Argument entries is a pointer of unsigned integer type. The number of
+elements is indicated in argument nvec. The content of each element
+will be mapped to the following struct defined in /driver/pci/msi.h.
+
+struct msix_entry {
+ u16 vector; /* kernel uses to write alloc vector */
+ u16 entry; /* driver uses to specify entry */
+};
+
+A device driver is responsible for initializing the field entry of
+each element with unique entry supported by MSI-X table. Otherwise,
+-EINVAL will be returned as a result. A successful return of zero
+indicates the PCI subsystem completes initializing each of requested
+entries of the MSI-X table with message address and message data.
+Last but not least, the PCI subsystem will write the 1:1
+vector-to-entry mapping into the field vector of each element. A
+device driver is responsible of keeping track of allocated MSI-X
+vectors in its internal data structure.
+
Argument nvec is an integer indicating the number of messages
requested.
-A return of zero indicates that the number of allocated vector is
-successfully allocated. Otherwise, indicate resources not
-available.
-
-int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec)
-
-This API enables the software driver to inform the PCI subsystem
-that it is willing to release a number of vectors back to the
-MSI resource pool. Once invoked, the PCI subsystem disables each
-MSI-X entry associated with each vector stored in the argument 2.
-These vectors are no longer valid for the hardware device and
-its software driver to use.
-Argument dev points to the device (pci_dev) structure.
-Argument vector is a pointer of integer type. The number of
-elements is indicated in argument nvec.
-Argument nvec is an integer indicating the number of messages
-released.
-A return of zero indicates that the number of allocated vectors
-is successfully released. Otherwise, indicates a failure.
+A return of zero indicates that the number of MSI-X vectors is
+successfully allocated. A return of greater than zero indicates
+MSI-X vector shortage. Or a return of less than zero indicates
+a failure. This failure may be a result of duplicate entries
+specified in second argument, or a result of no available vector,
+or a result of failing to initialize MSI-X table entries.
+
+5.3.5 API pci_disable_msix
+
+void pci_disable_msix(struct pci_dev *dev)
+
+This API is needed to encounter the case where a device driver is
+unloaded without doing request_irq on all ssigned MSI-X vector
+results a device being left in MSI-x mode and not be able to recover
+without rebooting. For example, a device driver does pci_enable_msix
+and is allocated 2 vectors, then correctly does request_irq/free_irq
+on one vector but does not touch the second vector. When a device
+driver is unloaded, it will be left in MSI-X mode. This API provides
+a device driver an ability to recover without rebooting and resolves
+vector leakage.
+
+5.3.6 MSI-X mode vs. legacy mode diagram
+
+The below diagram shows the events, which switches the interrupt
+mode on the MSI-X capable device function between MSI-X mode and
+PIN-IRQ assertion mode (legacy).
+
+ ------------ pci_enable_msix(,,n) ------------------------
+ | | <=============== | |
+ | MSI-X MODE | | PIN-IRQ ASSERTION MODE |
+ | | ===============> | |
+ ------------ (n)free_irq/ ------------------------
+ pci_disable_msix
+
+Figure 2.0 MSI-X Mode vs. Legacy Mode
+
+In Figure 2.0, a device operates by default in legacy mode. A
+successful MSI-X request (using pci_enable_msix()) switches a
+device's interrupt mode to MSI-X mode. A pre-assigned IOAPIC vector
+stored in dev->irq will be saved by the PCI subsystem; however,
+unlike MSI mode, the PCI subsystem will not replace dev->irq with
+assigned MSI-x vector because the PCI subsystem already writes the 1:1
+vector-to-entry mapping into the field vector of each element
+specified in second argument.
+
+To return back to its default mode, a device driver requires to call
+free_irq() on all allocated MSI vectors associated with doing
+request_irq. Unlike MSI mode, the PCI subsystem switches a device
+function back to its default legacy mode if and only if its device
+driver successfully releases all allocated MSI-X vectors correctly
+associated with request_irq/free_irq.
+
+Note that if a device still operates in MSI-X mode, its device
+driver can use request_irq/free_irq to any vectors in subset n. When
+the PCI subsystem detects all MSI-X vectors being released by a device
+driver, it will switches a function's interrupt mode from MSI-X mode
+to legacy mode and mark all allocated MSI-X vectors as unused. Once
+being marked as unused, there is no guarantee that the PCI subsystem
+will reserve these MSI-X vectors for a device. Depending on the
+availability of current PCI vector resources and the number of
+MSI/MSI-X requests from other drivers, these MSI-X vectors may be
+re-assigned. For the case where the PCI subsystem re-assigned
+these MSI-X vectors to other driver, a request to switching back to
+MSI-X mode may result being assigned with another set of MSI-X vectors
+or a failure.
+
+5.4 Handling function implementng both MSI and MSI-X capabilities
+
+For the case where a function implements both MSI and MSI-X
+capabilities, the PCI subsystem enables a device to run either in MSI
+mode or MSI-X mode but not both. A device driver determines whether it
+wants MSI or MSI-X enabled on its hardware device. Once a device
+driver requests for MSI, for example, it is prohibited to request for
+MSI-X; in other words, a device driver is not permitted to ping-pong
+between MSI mod MSI-X mode during a run-time.
-5.4 Hardware requirements for MSI support
-MSI support requires support from both system hardware and
+5.5 Hardware requirements for MSI/MSI-X support
+MSI/MSI-X support requires support from both system hardware and
individual hardware device functions.
-5.4.1 System hardware support
+5.5.1 System hardware support
Since the target of MSI address is the local APIC CPU, enabling
-MSI support in Linux kernel is dependent on whether existing
+MSI/MSI-X support in Linux kernel is dependent on whether existing
system hardware supports local APIC. Users should verify their
system whether it runs when CONFIG_X86_LOCAL_APIC=y.
@@ -231,14 +408,14 @@
CONFIG_X86_LOCAL_APIC. Once CONFIG_X86_LOCAL_APIC=y, setting
CONFIG_PCI_USE_VECTOR enables the VECTOR based scheme and
the option for MSI-capable device drivers to selectively enable
-MSI (using pci_enable_msi as described below).
+MSI/MSI-X.
-Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI
-vector is allocated new during runtime and MSI support does not
-depend on BIOS support. This key independency enables MSI support
-on future IOxAPIC free platform.
+Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI/MSI-X
+vector is allocated new during runtime and MSI/MSI-X support does not
+depend on BIOS support. This key independency enables MSI/MSI-X
+support on future IOxAPIC free platform.
-5.4.2 Device hardware support
+5.5.2 Device hardware support
The hardware device function supports MSI by indicating the
MSI/MSI-X capability structure on its PCI capability list. By
default, this capability structure will not be initialized by
@@ -249,17 +426,19 @@
MSI-capable hardware is responsible for whether calling
pci_enable_msi or not. A return of zero indicates the kernel
successfully initializes the MSI/MSI-X capability structure of the
-device funtion. The device function is now running on MSI mode.
+device funtion. The device function is now running on MSI/MSI-X mode.
-5.5 How to tell whether MSI is enabled on device function
+5.6 How to tell whether MSI/MSI-X is enabled on device function
-At the driver level, a return of zero from pci_enable_msi(...)
-indicates to the device driver that its device function is
-initialized successfully and ready to run in MSI mode.
+At the driver level, a return of zero from the function call of
+pci_enable_msi()/pci_enable_msix() indicates to a device driver that
+its device function is initialized successfully and ready to run in
+MSI/MSI-X mode.
At the user level, users can use command 'cat /proc/interrupts'
-to display the vector allocated for the device and its interrupt
-mode, as shown below.
+to display the vector allocated for a device and its interrupt
+MSI/MSI-X mode ("PCI MSI"/"PCI MSIX"). Below shows below MSI mode is
+enabled on a SCSI Adaptec 39320D Ultra320.
CPU0 CPU1
0: 324639 0 IO-APIC-edge timer
diff -urN linux-2.6.7/drivers/pci/msi.c patch-2.6.7-fix-msix/drivers/pci/msi.c
--- linux-2.6.7/drivers/pci/msi.c 2004-05-09 22:33:20.000000000 -0400
+++ patch-2.6.7-fix-msix/drivers/pci/msi.c 2004-06-25 14:43:10.000000000 -0400
@@ -67,12 +67,10 @@
unsigned int mask_bits;
pos = entry->mask_base;
- entry->dev->bus->ops->read(entry->dev->bus, entry->dev->devfn,
- pos, 4, &mask_bits);
+ pci_read_config_dword(entry->dev, pos, &mask_bits);
mask_bits &= ~(1);
mask_bits |= flag;
- entry->dev->bus->ops->write(entry->dev->bus, entry->dev->devfn,
- pos, 4, mask_bits);
+ pci_write_config_dword(entry->dev, pos, mask_bits);
break;
}
case PCI_CAP_ID_MSIX:
@@ -105,15 +103,13 @@
if (!(pos = pci_find_capability(entry->dev, PCI_CAP_ID_MSI)))
return;
- entry->dev->bus->ops->read(entry->dev->bus, entry->dev->devfn,
- msi_lower_address_reg(pos), 4,
+ pci_read_config_dword(entry->dev, msi_lower_address_reg(pos),
&address.lo_address.value);
address.lo_address.value &= MSI_ADDRESS_DEST_ID_MASK;
address.lo_address.value |= (cpu_mask_to_apicid(cpu_mask) <<
MSI_TARGET_CPU_SHIFT);
entry->msi_attrib.current_cpu = cpu_mask_to_apicid(cpu_mask);
- entry->dev->bus->ops->write(entry->dev->bus, entry->dev->devfn,
- msi_lower_address_reg(pos), 4,
+ pci_write_config_dword(entry->dev, msi_lower_address_reg(pos),
address.lo_address.value);
break;
}
@@ -158,13 +154,25 @@
static unsigned int startup_msi_irq_wo_maskbit(unsigned int vector)
{
+ struct msi_desc *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ entry = msi_desc[vector];
+ if (!entry || !entry->dev) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return 0;
+ }
+ entry->msi_attrib.state = 1; /* Mark it active */
+ spin_unlock_irqrestore(&msi_lock, flags);
+
return 0; /* never anything pending */
}
-static void pci_disable_msi(unsigned int vector);
+static void release_msi(unsigned int vector);
static void shutdown_msi_irq(unsigned int vector)
{
- pci_disable_msi(vector);
+ release_msi(vector);
}
#define shutdown_msi_irq_wo_maskbit shutdown_msi_irq
@@ -179,6 +187,18 @@
static unsigned int startup_msi_irq_w_maskbit(unsigned int vector)
{
+ struct msi_desc *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ entry = msi_desc[vector];
+ if (!entry || !entry->dev) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return 0;
+ }
+ entry->msi_attrib.state = 1; /* Mark it active */
+ spin_unlock_irqrestore(&msi_lock, flags);
+
unmask_MSI_irq(vector);
return 0; /* never anything pending */
}
@@ -200,7 +220,7 @@
* which implement the MSI-X Capability Structure.
*/
static struct hw_interrupt_type msix_irq_type = {
- .typename = "PCI MSI-X",
+ .typename = "PCI-MSI-X",
.startup = startup_msi_irq_w_maskbit,
.shutdown = shutdown_msi_irq_w_maskbit,
.enable = enable_msi_irq_w_maskbit,
@@ -216,7 +236,7 @@
* Mask-and-Pending Bits.
*/
static struct hw_interrupt_type msi_irq_w_maskbit_type = {
- .typename = "PCI MSI",
+ .typename = "PCI-MSI",
.startup = startup_msi_irq_w_maskbit,
.shutdown = shutdown_msi_irq_w_maskbit,
.enable = enable_msi_irq_w_maskbit,
@@ -232,7 +252,7 @@
* Mask-and-Pending Bits.
*/
static struct hw_interrupt_type msi_irq_wo_maskbit_type = {
- .typename = "PCI MSI",
+ .typename = "PCI-MSI",
.startup = startup_msi_irq_wo_maskbit,
.shutdown = shutdown_msi_irq_wo_maskbit,
.enable = enable_msi_irq_wo_maskbit,
@@ -265,6 +285,7 @@
msi_address->lo_address.value |= (MSI_TARGET_CPU << MSI_TARGET_CPU_SHIFT);
}
+static int msi_free_vector(struct pci_dev* dev, int vector, int reassign);
static int assign_msi_vector(void)
{
static int new_vector_avail = 1;
@@ -278,6 +299,8 @@
spin_lock_irqsave(&msi_lock, flags);
if (!new_vector_avail) {
+ int free_vector = 0;
+
/*
* vector_irq[] = -1 indicates that this specific vector is:
* - assigned for MSI (since MSI have no associated IRQ) or
@@ -294,13 +317,34 @@
for (vector = FIRST_DEVICE_VECTOR; vector < NR_IRQS; vector++) {
if (vector_irq[vector] != 0)
continue;
- vector_irq[vector] = -1;
- nr_released_vectors--;
- spin_unlock_irqrestore(&msi_lock, flags);
- return vector;
+ free_vector = vector;
+ if (!msi_desc[vector])
+ break;
+ else
+ continue;
}
+ if (!free_vector) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return -EBUSY;
+ }
+ vector_irq[free_vector] = -1;
+ nr_released_vectors--;
spin_unlock_irqrestore(&msi_lock, flags);
- return -EBUSY;
+ if (msi_desc[free_vector] != NULL) {
+ struct pci_dev *dev;
+ int tail;
+
+ /* free all linked vectors before re-assign */
+ do {
+ spin_lock_irqsave(&msi_lock, flags);
+ dev = msi_desc[free_vector]->dev;
+ tail = msi_desc[free_vector]->link.tail;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ msi_free_vector(dev, tail, 1);
+ } while (free_vector != tail);
+ }
+
+ return free_vector;
}
vector = assign_irq_vector(AUTO_ASSIGN);
last_alloc_vector = vector;
@@ -333,6 +377,15 @@
printk(KERN_INFO "WARNING: MSI INIT FAILURE\n");
return status;
}
+ last_alloc_vector = assign_irq_vector(AUTO_ASSIGN);
+ if (last_alloc_vector < 0) {
+ pci_msi_enable = 0;
+ printk(KERN_INFO "WARNING: ALL VECTORS ARE BUSY\n");
+ status = -EBUSY;
+ return status;
+ }
+ vector_irq[last_alloc_vector] = 0;
+ nr_released_vectors++;
printk(KERN_INFO "MSI INIT SUCCESS\n");
return status;
@@ -383,55 +436,49 @@
static void enable_msi_mode(struct pci_dev *dev, int pos, int type)
{
- u32 control;
+ u16 control;
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, &control);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
if (type == PCI_CAP_ID_MSI) {
/* Set enabled bits to single MSI & enable MSI_enable bit */
msi_enable(control, 1);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
} else {
msix_enable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
}
if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
/* PCI Express Endpoint device detected */
- u32 cmd;
- dev->bus->ops->read(dev->bus, dev->devfn, PCI_COMMAND, 2, &cmd);
+ u16 cmd;
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
cmd |= PCI_COMMAND_INTX_DISABLE;
- dev->bus->ops->write(dev->bus, dev->devfn, PCI_COMMAND, 2, cmd);
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
}
}
static void disable_msi_mode(struct pci_dev *dev, int pos, int type)
{
- u32 control;
+ u16 control;
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, &control);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
if (type == PCI_CAP_ID_MSI) {
/* Set enabled bits to single MSI & enable MSI_enable bit */
msi_disable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
} else {
msix_disable(control);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_control_reg(pos), 2, control);
+ pci_write_config_word(dev, msi_control_reg(pos), control);
}
if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
/* PCI Express Endpoint device detected */
- u32 cmd;
- dev->bus->ops->read(dev->bus, dev->devfn, PCI_COMMAND, 2, &cmd);
+ u16 cmd;
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
cmd &= ~PCI_COMMAND_INTX_DISABLE;
- dev->bus->ops->write(dev->bus, dev->devfn, PCI_COMMAND, 2, cmd);
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
}
}
-static int msi_lookup_vector(struct pci_dev *dev)
+static int msi_lookup_vector(struct pci_dev *dev, int type)
{
int vector;
unsigned long flags;
@@ -439,11 +486,11 @@
spin_lock_irqsave(&msi_lock, flags);
for (vector = FIRST_DEVICE_VECTOR; vector < NR_IRQS; vector++) {
if (!msi_desc[vector] || msi_desc[vector]->dev != dev ||
- msi_desc[vector]->msi_attrib.entry_nr ||
+ msi_desc[vector]->msi_attrib.type != type ||
msi_desc[vector]->msi_attrib.default_vector != dev->irq)
- continue; /* not entry 0, skip */
+ continue;
spin_unlock_irqrestore(&msi_lock, flags);
- /* This pre-assigned entry-0 MSI vector for this device
+ /* This pre-assigned MSI vector for this device
already exits. Override dev->irq with this vector */
dev->irq = vector;
return 0;
@@ -458,10 +505,9 @@
if (!dev)
return;
- if (pci_find_capability(dev, PCI_CAP_ID_MSIX) > 0) {
- nr_reserved_vectors++;
+ if (pci_find_capability(dev, PCI_CAP_ID_MSIX) > 0)
nr_msix_devices++;
- } else if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0)
+ else if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0)
nr_reserved_vectors++;
}
@@ -480,22 +526,10 @@
struct msg_address address;
struct msg_data data;
int pos, vector;
- u32 control;
+ u16 control;
pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
- if (!pos)
- return -EINVAL;
-
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos),
- 2, &control);
- if (control & PCI_MSI_FLAGS_ENABLE)
- return 0;
-
- if (!msi_lookup_vector(dev)) {
- /* Lookup Sucess */
- enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
- return 0;
- }
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
/* MSI Entry Initialization */
if (!(entry = alloc_msi_entry()))
return -ENOMEM;
@@ -504,11 +538,14 @@
kmem_cache_free(msi_cachep, entry);
return -EBUSY;
}
+ entry->link.head = vector;
+ entry->link.tail = vector;
entry->msi_attrib.type = PCI_CAP_ID_MSI;
+ entry->msi_attrib.state = 0; /* Mark it not active */
entry->msi_attrib.entry_nr = 0;
entry->msi_attrib.maskbit = is_mask_bit_support(control);
- entry->msi_attrib.default_vector = dev->irq;
- dev->irq = vector; /* save default pre-assigned ioapic vector */
+ entry->msi_attrib.default_vector = dev->irq; /* Save IOAPIC IRQ */
+ dev->irq = vector;
entry->dev = dev;
if (is_mask_bit_support(control)) {
entry->mask_base = msi_mask_bits_reg(pos,
@@ -521,27 +558,27 @@
msi_data_init(&data, vector);
entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- dev->bus->ops->write(dev->bus, dev->devfn, msi_lower_address_reg(pos),
- 4, address.lo_address.value);
+ pci_write_config_dword(dev, msi_lower_address_reg(pos),
+ address.lo_address.value);
if (is_64bit_address(control)) {
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_upper_address_reg(pos), 4, address.hi_address);
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_data_reg(pos, 1), 2, *((u32*)&data));
+ pci_write_config_dword(dev,
+ msi_upper_address_reg(pos), address.hi_address);
+ pci_write_config_word(dev,
+ msi_data_reg(pos, 1), *((u32*)&data));
} else
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_data_reg(pos, 0), 2, *((u32*)&data));
+ pci_write_config_word(dev,
+ msi_data_reg(pos, 0), *((u32*)&data));
if (entry->msi_attrib.maskbit) {
unsigned int maskbits, temp;
/* All MSIs are unmasked by default, Mask them all */
- dev->bus->ops->read(dev->bus, dev->devfn,
- msi_mask_bits_reg(pos, is_64bit_address(control)), 4,
+ pci_read_config_dword(dev,
+ msi_mask_bits_reg(pos, is_64bit_address(control)),
&maskbits);
temp = (1 << multi_msi_capable(control));
temp = ((temp - 1) & ~temp);
maskbits |= temp;
- dev->bus->ops->write(dev->bus, dev->devfn,
- msi_mask_bits_reg(pos, is_64bit_address(control)), 4,
+ pci_write_config_dword(dev,
+ msi_mask_bits_reg(pos, is_64bit_address(control)),
maskbits);
}
attach_msi_entry(entry, vector);
@@ -556,135 +593,208 @@
* @dev: pointer to the pci_dev data structure of MSI-X device function
*
* Setup the MSI-X capability structure of device funtion with a
- * single MSI-X vector. A return of zero indicates the successful setup
- * of an entry zero with the new MSI-X vector or non-zero for otherwise.
- * To request for additional MSI-X vectors, the device drivers are
- * required to utilize the following supported APIs:
- * 1) msi_alloc_vectors(...) for requesting one or more MSI-X vectors
- * 2) msi_free_vectors(...) for releasing one or more MSI-X vectors
- * back to PCI subsystem before calling free_irq(...)
+ * single MSI-X vector. A return of zero indicates the successful setup of
+ * requested MSI-X entries with allocated vectors or non-zero for otherwise.
**/
-static int msix_capability_init(struct pci_dev *dev)
+static int msix_capability_init(struct pci_dev *dev,
+ struct msix_entry *entries, int nvec)
{
- struct msi_desc *entry;
+ struct msi_desc *head = NULL, *tail = NULL, *entry = NULL;
struct msg_address address;
struct msg_data data;
- int vector = 0, pos, dev_msi_cap;
+ int vector, pos, i, j, nr_entries, temp = 0;
u32 phys_addr, table_offset;
- u32 control;
+ u16 control;
u8 bir;
void *base;
-
+
pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- if (!pos)
- return -EINVAL;
-
/* Request & Map MSI-X table region */
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2,
- &control);
- if (control & PCI_MSIX_FLAGS_ENABLE)
- return 0;
-
- if (!msi_lookup_vector(dev)) {
- /* Lookup Sucess */
- enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
- return 0;
- }
-
- dev_msi_cap = multi_msix_capable(control);
- dev->bus->ops->read(dev->bus, dev->devfn,
- msix_table_offset_reg(pos), 4, &table_offset);
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ nr_entries = multi_msix_capable(control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
phys_addr = pci_resource_start (dev, bir);
phys_addr += (u32)(table_offset & ~PCI_MSIX_FLAGS_BIRMASK);
if (!request_mem_region(phys_addr,
- dev_msi_cap * PCI_MSIX_ENTRY_SIZE,
- "MSI-X iomap Failure"))
+ nr_entries * PCI_MSIX_ENTRY_SIZE,
+ "MSI-X vector table"))
return -ENOMEM;
- base = ioremap_nocache(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
- if (base == NULL)
- goto free_region;
- /* MSI Entry Initialization */
- entry = alloc_msi_entry();
- if (!entry)
- goto free_iomap;
- if ((vector = get_msi_vector(dev)) < 0)
- goto free_entry;
-
- entry->msi_attrib.type = PCI_CAP_ID_MSIX;
- entry->msi_attrib.entry_nr = 0;
- entry->msi_attrib.maskbit = 1;
- entry->msi_attrib.default_vector = dev->irq;
- dev->irq = vector; /* save default pre-assigned ioapic vector */
- entry->dev = dev;
- entry->mask_base = (unsigned long)base;
- /* Replace with MSI handler */
- irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
- /* Configure MSI-X capability structure */
- msi_address_init(&address);
- msi_data_init(&data, vector);
- entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
- MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- writel(address.lo_address.value, base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(address.hi_address, base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(*(u32*)&data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
- /* Initialize all entries from 1 up to 0 */
- for (pos = 1; pos < dev_msi_cap; pos++) {
- writel(0, base + pos * PCI_MSIX_ENTRY_SIZE +
+ base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
+ if (base == NULL) {
+ release_mem_region(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
+ return -ENOMEM;
+ }
+ /* MSI-X Table Initialization */
+ for (i = 0; i < nvec; i++) {
+ entry = alloc_msi_entry();
+ if (!entry)
+ break;
+ if ((vector = get_msi_vector(dev)) < 0)
+ break;
+
+ j = entries[i].entry;
+ entries[i].vector = vector;
+ entry->msi_attrib.type = PCI_CAP_ID_MSIX;
+ entry->msi_attrib.state = 0; /* Mark it not active */
+ entry->msi_attrib.entry_nr = j;
+ entry->msi_attrib.maskbit = 1;
+ entry->msi_attrib.default_vector = dev->irq;
+ entry->dev = dev;
+ entry->mask_base = (unsigned long)base;
+ if (!head) {
+ entry->link.head = vector;
+ entry->link.tail = vector;
+ head = entry;
+ } else {
+ entry->link.head = temp;
+ entry->link.tail = tail->link.tail;
+ tail->link.tail = vector;
+ head->link.head = vector;
+ }
+ temp = vector;
+ tail = entry;
+ /* Replace with MSI-X handler */
+ irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
+ /* Configure MSI-X capability structure */
+ msi_address_init(&address);
+ msi_data_init(&data, vector);
+ entry->msi_attrib.current_cpu =
+ ((address.lo_address.u.dest_id >>
+ MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
+ writel(address.lo_address.value,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(0, base + pos * PCI_MSIX_ENTRY_SIZE +
+ writel(address.hi_address,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(0, base + pos * PCI_MSIX_ENTRY_SIZE +
+ writel(*(u32*)&data,
+ base + j * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_DATA_OFFSET);
+ attach_msi_entry(entry, vector);
}
- attach_msi_entry(entry, vector);
- /* Set MSI enabled bits */
+ if (i != nvec) {
+ i--;
+ for (; i >= 0; i--) {
+ vector = (entries + i)->vector;
+ msi_free_vector(dev, vector, 0);
+ (entries + i)->vector = 0;
+ }
+ return -EBUSY;
+ }
+ /* Set MSI-X enabled bits */
enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
-
+
return 0;
-
-free_entry:
- kmem_cache_free(msi_cachep, entry);
-free_iomap:
- iounmap(base);
-free_region:
- release_mem_region(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
-
- return ((vector < 0) ? -EBUSY : -ENOMEM);
}
/**
- * pci_enable_msi - configure device's MSI(X) capability structure
- * @dev: pointer to the pci_dev data structure of MSI(X) device function
+ * pci_enable_msi - configure device's MSI capability structure
+ * @dev: pointer to the pci_dev data structure of MSI device function
*
- * Setup the MSI/MSI-X capability structure of device function with
- * a single MSI(X) vector upon its software driver call to request for
- * MSI(X) mode enabled on its hardware device function. A return of zero
- * indicates the successful setup of an entry zero with the new MSI(X)
+ * Setup the MSI capability structure of device function with
+ * a single MSI vector upon its software driver call to request for
+ * MSI mode enabled on its hardware device function. A return of zero
+ * indicates the successful setup of an entry zero with the new MSI
* vector or non-zero for otherwise.
**/
int pci_enable_msi(struct pci_dev* dev)
{
- int status = -EINVAL;
+ int pos, temp = dev->irq, status = -EINVAL;
+ u16 control;
if (!pci_msi_enable || !dev)
return status;
- if (msi_init() < 0)
- return -ENOMEM;
+ if ((status = msi_init()) < 0)
+ return status;
- if ((status = msix_capability_init(dev)) == -EINVAL)
- status = msi_capability_init(dev);
- if (!status)
- nr_reserved_vectors--;
+ if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
+ return -EINVAL;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (control & PCI_MSI_FLAGS_ENABLE)
+ return 0; /* Already in MSI mode */
+
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ /* Lookup Sucess */
+ unsigned long flags;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ if (!vector_irq[dev->irq]) {
+ msi_desc[dev->irq]->msi_attrib.state = 0;
+ vector_irq[dev->irq] = -1;
+ nr_released_vectors--;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ enable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
+ return 0;
+ }
+ spin_unlock_irqrestore(&msi_lock, flags);
+ dev->irq = temp;
+ }
+ /* Check whether driver already requested for MSI-X vectors */
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ printk(KERN_INFO "Can't enable MSI. Device already had MSI-X vectors assigned\n");
+ dev->irq = temp;
+ return -EINVAL;
+ }
+ status = msi_capability_init(dev);
+ if (!status) {
+ if (!pos)
+ nr_reserved_vectors--; /* Only MSI capable */
+ else if (nr_msix_devices > 0)
+ nr_msix_devices--; /* Both MSI and MSI-X capable,
+ but choose enabling MSI */
+ }
return status;
}
-static int msi_free_vector(struct pci_dev* dev, int vector);
-static void pci_disable_msi(unsigned int vector)
+void pci_disable_msi(struct pci_dev* dev)
{
- int head, tail, type, default_vector;
+ struct msi_desc *entry;
+ int pos, default_vector;
+ u16 control;
+ unsigned long flags;
+
+ if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSI)))
+ return;
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (!(control & PCI_MSI_FLAGS_ENABLE))
+ return;
+
+ spin_lock_irqsave(&msi_lock, flags);
+ entry = msi_desc[dev->irq];
+ if (!entry || !entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ return;
+ }
+ if (entry->msi_attrib.state) {
+ spin_unlock_irqrestore(&msi_lock, flags);
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on vector->%d\n",
+ dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn),
+ dev->irq);
+ BUG_ON(entry->msi_attrib.state > 0);
+ } else {
+ if (vector_irq[dev->irq] != 0) {
+ vector_irq[dev->irq] = 0; /* free it */
+ nr_released_vectors++;
+ }
+ default_vector = entry->msi_attrib.default_vector;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ /* Restore dev->irq to its default pin-assertion vector */
+ dev->irq = default_vector;
+ disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
+ PCI_CAP_ID_MSI);
+ }
+}
+
+static void release_msi(unsigned int vector)
+{
+ int type, default_vector;
struct msi_desc *entry;
struct pci_dev *dev;
unsigned long flags;
@@ -697,168 +807,233 @@
}
dev = entry->dev;
type = entry->msi_attrib.type;
- head = entry->link.head;
- tail = entry->link.tail;
+ entry->msi_attrib.state = 0; /* Mark it not active */
default_vector = entry->msi_attrib.default_vector;
spin_unlock_irqrestore(&msi_lock, flags);
-
- disable_msi_mode(dev, pci_find_capability(dev, type), type);
- /* Restore dev->irq to its default pin-assertion vector */
- dev->irq = default_vector;
- if (type == PCI_CAP_ID_MSIX && head != tail) {
- /* Bad driver, which do not call msi_free_vectors before exit.
- We must do a cleanup here */
- while (1) {
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[vector];
- head = entry->link.head;
- tail = entry->link.tail;
+ switch (type) {
+ case PCI_CAP_ID_MSI:
+ spin_lock_irqsave(&msi_lock, flags);
+ vector_irq[vector] = 0; /* Mark it free */
+ nr_released_vectors++;
+ spin_unlock_irqrestore(&msi_lock, flags);
+ break;
+ case PCI_CAP_ID_MSIX:
+ spin_lock_irqsave(&msi_lock, flags);
+ while (vector != entry->link.tail) {
+ entry = msi_desc[entry->link.tail];
+ if (!entry->msi_attrib.state)
+ continue;
spin_unlock_irqrestore(&msi_lock, flags);
- if (tail == head)
- break;
- if (msi_free_vector(dev, entry->link.tail))
- break;
+ /*
+ * Device still operates in MSI-X mode. Do not
+ * switch interrupt mode
+ */
+ return;
}
+ entry = msi_desc[vector];
+ vector_irq[vector] = 0; /* Mark it free */
+ nr_released_vectors++;
+ while (vector != entry->link.tail) {
+ vector_irq[entry->link.tail] = 0; /* Mark it free */
+ nr_released_vectors++;
+ entry = msi_desc[entry->link.tail];
+ }
+ spin_unlock_irqrestore(&msi_lock, flags);
+ break;
+ default:
+ return;
}
+ /* Restore dev->irq to its default pin-assertion vector */
+ dev->irq = default_vector;
+ disable_msi_mode(dev, pci_find_capability(dev, type), type);
}
-static int msi_alloc_vector(struct pci_dev* dev, int head)
+static int msi_free_vector(struct pci_dev* dev, int vector, int reassign)
{
struct msi_desc *entry;
- struct msg_address address;
- struct msg_data data;
- int i, offset, pos, dev_msi_cap, vector;
- u32 low_address, control;
+ int head, entry_nr, type;
unsigned long base = 0L;
unsigned long flags;
spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry) {
+ entry = msi_desc[vector];
+ if (!entry || entry->dev != dev) {
spin_unlock_irqrestore(&msi_lock, flags);
return -EINVAL;
}
+ type = entry->msi_attrib.type;
+ entry_nr = entry->msi_attrib.entry_nr;
+ head = entry->link.head;
base = entry->mask_base;
- spin_unlock_irqrestore(&msi_lock, flags);
-
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos),
- 2, &control);
- dev_msi_cap = multi_msix_capable(control);
- for (i = 1; i < dev_msi_cap; i++) {
- if (!(low_address = readl(base + i * PCI_MSIX_ENTRY_SIZE)))
- break;
+ msi_desc[entry->link.head]->link.tail = entry->link.tail;
+ msi_desc[entry->link.tail]->link.head = entry->link.head;
+ entry->dev = NULL;
+ if (!reassign) {
+ vector_irq[vector] = 0;
+ nr_released_vectors++;
}
- if (i >= dev_msi_cap)
- return -EINVAL;
+ msi_desc[vector] = NULL;
+ spin_unlock_irqrestore(&msi_lock, flags);
- /* MSI Entry Initialization */
- if (!(entry = alloc_msi_entry()))
- return -ENOMEM;
+ kmem_cache_free(msi_cachep, entry);
- if ((vector = get_new_vector()) < 0) {
- kmem_cache_free(msi_cachep, entry);
- return vector;
+ if (type == PCI_CAP_ID_MSIX) {
+ if (!reassign)
+ writel(1, base +
+ entry_nr * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
+
+ if (head == vector) {
+ /*
+ * Detect last MSI-X vector to be released.
+ * Release the MSI-X memory-mapped table.
+ */
+ int pos, nr_entries;
+ u32 phys_addr, table_offset;
+ u16 control;
+ u8 bir;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+ pci_read_config_word(dev, msi_control_reg(pos),
+ &control);
+ nr_entries = multi_msix_capable(control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
+ bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
+ phys_addr = pci_resource_start (dev, bir);
+ phys_addr += (u32)(table_offset &
+ ~PCI_MSIX_FLAGS_BIRMASK);
+ iounmap((void*)base);
+ release_mem_region(phys_addr,
+ nr_entries * PCI_MSIX_ENTRY_SIZE);
+ }
}
- entry->msi_attrib.type = PCI_CAP_ID_MSIX;
- entry->msi_attrib.entry_nr = i;
- entry->msi_attrib.maskbit = 1;
- entry->dev = dev;
- entry->link.head = head;
- entry->mask_base = base;
- irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
- /* Configure MSI-X capability structure */
- msi_address_init(&address);
- msi_data_init(&data, vector);
- entry->msi_attrib.current_cpu = ((address.lo_address.u.dest_id >>
- MSI_TARGET_CPU_SHIFT) & MSI_TARGET_CPU_MASK);
- offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
- writel(address.lo_address.value, base + offset +
- PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- writel(address.hi_address, base + offset +
- PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
- writel(*(u32*)&data, base + offset + PCI_MSIX_ENTRY_DATA_OFFSET);
- writel(1, base + offset + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- attach_msi_entry(entry, vector);
- return vector;
+ return 0;
}
-static int msi_free_vector(struct pci_dev* dev, int vector)
+static int reroute_msix_table(int head, struct msix_entry *entries, int *nvec)
{
- struct msi_desc *entry;
- int entry_nr, type;
+ int vector = head, tail = 0;
+ int i = 0, j = 0, nr_entries = 0;
unsigned long base = 0L;
unsigned long flags;
-
+
spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[vector];
- if (!entry || entry->dev != dev) {
+ while (head != tail) {
+ nr_entries++;
+ tail = msi_desc[vector]->link.tail;
+ if (entries[0].entry == msi_desc[vector]->msi_attrib.entry_nr)
+ j = vector;
+ vector = tail;
+ }
+ if (*nvec > nr_entries) {
spin_unlock_irqrestore(&msi_lock, flags);
+ *nvec = nr_entries;
return -EINVAL;
}
- type = entry->msi_attrib.type;
- entry_nr = entry->msi_attrib.entry_nr;
- base = entry->mask_base;
- if (entry->link.tail != entry->link.head) {
- msi_desc[entry->link.head]->link.tail = entry->link.tail;
- if (entry->link.tail)
- msi_desc[entry->link.tail]->link.head = entry->link.head;
+ vector = ((j > 0) ? j : head);
+ for (i = 0; i < *nvec; i++) {
+ j = msi_desc[vector]->msi_attrib.entry_nr;
+ msi_desc[vector]->msi_attrib.state = 0; /* Mark it not active */
+ vector_irq[vector] = -1; /* Mark it busy */
+ nr_released_vectors--;
+ entries[i].vector = vector;
+ if (j != (entries + i)->entry) {
+ base = msi_desc[vector]->mask_base;
+ msi_desc[vector]->msi_attrib.entry_nr =
+ (entries + i)->entry;
+ writel( readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET), base +
+ (entries + i)->entry * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+ writel( readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET), base +
+ (entries + i)->entry * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+ writel( (readl(base + j * PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_DATA_OFFSET) & 0xff00) | vector,
+ base + (entries+i)->entry*PCI_MSIX_ENTRY_SIZE +
+ PCI_MSIX_ENTRY_DATA_OFFSET);
+ }
+ vector = msi_desc[vector]->link.tail;
}
- entry->dev = NULL;
- vector_irq[vector] = 0;
- nr_released_vectors++;
- msi_desc[vector] = NULL;
spin_unlock_irqrestore(&msi_lock, flags);
-
- kmem_cache_free(msi_cachep, entry);
- if (type == PCI_CAP_ID_MSIX) {
- int offset;
-
- offset = entry_nr * PCI_MSIX_ENTRY_SIZE;
- writel(1, base + offset + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- writel(0, base + offset + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
- }
-
+
return 0;
}
/**
- * msi_alloc_vectors - allocate additional MSI-X vectors
+ * pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
- * @vector: pointer to an array of new allocated MSI-X vectors
+ * @data: pointer to an array of MSI-X entries
* @nvec: number of MSI-X vectors requested for allocation by device driver
*
- * Allocate additional MSI-X vectors requested by device driver. A
- * return of zero indicates the successful setup of MSI-X capability
- * structure with new allocated MSI-X vectors or non-zero for otherwise.
+ * Setup the MSI-X capability structure of device function with the number
+ * of requested vectors upon its software driver call to request for
+ * MSI-X mode enabled on its hardware device function. A return of zero
+ * indicates the successful configuration of MSI-X capability structure
+ * with new allocated MSI-X vectors. A return of < 0 indicates a failure.
+ * Or a return of > 0 indicates that driver request is exceeding the number
+ * of vectors available. Driver should use the returned value to re-send
+ * its request.
**/
-int msi_alloc_vectors(struct pci_dev* dev, int *vector, int nvec)
+int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
{
- struct msi_desc *entry;
- int i, head, pos, vec, free_vectors, alloc_vectors;
- int *vectors = (int *)vector;
- u32 control;
+ int status, pos, nr_entries, free_vectors;
+ int i, j, temp;
+ u16 control;
unsigned long flags;
- if (!pci_msi_enable || !dev)
+ if (!pci_msi_enable || !dev || !entries)
return -EINVAL;
-
+
+ if ((status = msi_init()) < 0)
+ return status;
+
if (!(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
return -EINVAL;
-
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2, &control);
- if (nvec > multi_msix_capable(control))
- return -EINVAL;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev || /* legal call */
- entry->msi_attrib.type != PCI_CAP_ID_MSIX || /* must be MSI-X */
- entry->link.head != entry->link.tail) { /* already multi */
- spin_unlock_irqrestore(&msi_lock, flags);
+
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (control & PCI_MSIX_FLAGS_ENABLE)
+ return -EINVAL; /* Already in MSI-X mode */
+
+ nr_entries = multi_msix_capable(control);
+ if (nvec > nr_entries)
return -EINVAL;
+
+ /* Check for any invalid entries */
+ for (i = 0; i < nvec; i++) {
+ if (entries[i].entry >= nr_entries)
+ return -EINVAL; /* invalid entry */
+ for (j = i + 1; j < nvec; j++) {
+ if (entries[i].entry == entries[j].entry)
+ return -EINVAL; /* duplicate entry */
+ }
}
+ temp = dev->irq;
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ /* Lookup Sucess */
+ nr_entries = nvec;
+ /* Reroute MSI-X table */
+ if (reroute_msix_table(dev->irq, entries, &nr_entries)) {
+ /* #requested > #previous-assigned */
+ dev->irq = temp;
+ return nr_entries;
+ }
+ dev->irq = temp;
+ enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
+ return 0;
+ }
+ /* Check whether driver already requested for MSI vector */
+ if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ printk(KERN_INFO "Can't enable MSI-X. Device already had MSI vector assigned\n");
+ dev->irq = temp;
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&msi_lock, flags);
/*
* msi_lock is provided to ensure that enough vectors resources are
* available before granting.
@@ -874,71 +1049,66 @@
free_vectors /= nr_msix_devices;
spin_unlock_irqrestore(&msi_lock, flags);
- if (nvec > free_vectors)
- return -EBUSY;
+ if (nvec > free_vectors) {
+ if (free_vectors > 0)
+ return free_vectors;
+ else
+ return -EBUSY;
+ }
- alloc_vectors = 0;
- head = dev->irq;
- for (i = 0; i < nvec; i++) {
- if ((vec = msi_alloc_vector(dev, head)) < 0)
- break;
- *(vectors + i) = vec;
- head = vec;
- alloc_vectors++;
- }
- if (alloc_vectors != nvec) {
- for (i = 0; i < alloc_vectors; i++) {
- vec = *(vectors + i);
- msi_free_vector(dev, vec);
- }
- spin_lock_irqsave(&msi_lock, flags);
- msi_desc[dev->irq]->link.tail = msi_desc[dev->irq]->link.head;
- spin_unlock_irqrestore(&msi_lock, flags);
- return -EBUSY;
- }
- if (nr_msix_devices > 0)
+ status = msix_capability_init(dev, entries, nvec);
+ if (!status && nr_msix_devices > 0)
nr_msix_devices--;
-
- return 0;
+
+ return status;
}
-/**
- * msi_free_vectors - reclaim MSI-X vectors to unused state
- * @dev: pointer to the pci_dev data structure of MSI-X device function
- * @vector: pointer to an array of released MSI-X vectors
- * @nvec: number of MSI-X vectors requested for release by device driver
- *
- * Reclaim MSI-X vectors released by device driver to unused state,
- * which may be used later on. A return of zero indicates the
- * success or non-zero for otherwise. Device driver should call this
- * before calling function free_irq.
- **/
-int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec)
+void pci_disable_msix(struct pci_dev* dev)
{
- struct msi_desc *entry;
- int i;
- unsigned long flags;
+ int pos, temp;
+ u16 control;
+
+ if (!dev || !(pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)))
+ return;
- if (!pci_msi_enable)
- return -EINVAL;
+ pci_read_config_word(dev, msi_control_reg(pos), &control);
+ if (!(control & PCI_MSIX_FLAGS_ENABLE))
+ return;
+ temp = dev->irq;
+ if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ int state, vector, head, tail = 0, warning = 0;
+ unsigned long flags;
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev ||
- entry->msi_attrib.type != PCI_CAP_ID_MSIX ||
- entry->link.head == entry->link.tail) { /* Nothing to free */
+ vector = head = dev->irq;
+ spin_lock_irqsave(&msi_lock, flags);
+ while (head != tail) {
+ state = msi_desc[vector]->msi_attrib.state;
+ if (state)
+ warning = 1;
+ else {
+ if (vector_irq[vector] != 0) {
+ vector_irq[vector] = 0; /* free it */
+ nr_released_vectors++;
+ }
+ }
+ tail = msi_desc[vector]->link.tail;
+ vector = tail;
+ }
spin_unlock_irqrestore(&msi_lock, flags);
- return -EINVAL;
- }
- spin_unlock_irqrestore(&msi_lock, flags);
+ if (warning) {
+ dev->irq = temp;
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on all vectors\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn));
+ BUG_ON(warning > 0);
+ } else {
+ dev->irq = temp;
+ disable_msi_mode(dev,
+ pci_find_capability(dev, PCI_CAP_ID_MSIX),
+ PCI_CAP_ID_MSIX);
- for (i = 0; i < nvec; i++) {
- if (*(vector + i) == dev->irq)
- continue;/* Don't free entry 0 if mistaken by driver */
- msi_free_vector(dev, *(vector + i));
+ }
}
-
- return 0;
}
/**
@@ -952,62 +1122,73 @@
**/
void msi_remove_pci_irq_vectors(struct pci_dev* dev)
{
- struct msi_desc *entry;
- int type, temp;
+ int state, pos, temp;
unsigned long flags;
-
+
if (!pci_msi_enable || !dev)
return;
-
- if (!pci_find_capability(dev, PCI_CAP_ID_MSI)) {
- if (!pci_find_capability(dev, PCI_CAP_ID_MSIX))
- return;
- }
- temp = dev->irq;
- if (msi_lookup_vector(dev))
- return;
-
- spin_lock_irqsave(&msi_lock, flags);
- entry = msi_desc[dev->irq];
- if (!entry || entry->dev != dev) {
+
+ temp = dev->irq; /* Save IOAPIC IRQ */
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSI)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSI)) {
+ spin_lock_irqsave(&msi_lock, flags);
+ state = msi_desc[dev->irq]->msi_attrib.state;
spin_unlock_irqrestore(&msi_lock, flags);
- return;
- }
- type = entry->msi_attrib.type;
- spin_unlock_irqrestore(&msi_lock, flags);
-
- msi_free_vector(dev, dev->irq);
- if (type == PCI_CAP_ID_MSIX) {
- int i, pos, dev_msi_cap;
- u32 phys_addr, table_offset;
- u32 control;
- u8 bir;
-
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- dev->bus->ops->read(dev->bus, dev->devfn, msi_control_reg(pos), 2, &control);
- dev_msi_cap = multi_msix_capable(control);
- dev->bus->ops->read(dev->bus, dev->devfn,
- msix_table_offset_reg(pos), 4, &table_offset);
- bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
- phys_addr = pci_resource_start (dev, bir);
- phys_addr += (u32)(table_offset & ~PCI_MSIX_FLAGS_BIRMASK);
- for (i = FIRST_DEVICE_VECTOR; i < NR_IRQS; i++) {
+ if (state) {
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on vector->%d\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn), dev->irq);
+ BUG_ON(state > 0);
+ } else /* Release MSI vector assigned to this device */
+ msi_free_vector(dev, dev->irq, 0);
+ dev->irq = temp; /* Restore IOAPIC IRQ */
+ }
+ if ((pos = pci_find_capability(dev, PCI_CAP_ID_MSIX)) > 0 &&
+ !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) {
+ int vector, head, tail = 0, warning = 0;
+ unsigned long base = 0L;
+
+ vector = head = dev->irq;
+ while (head != tail) {
spin_lock_irqsave(&msi_lock, flags);
- if (!msi_desc[i] || msi_desc[i]->dev != dev) {
- spin_unlock_irqrestore(&msi_lock, flags);
- continue;
- }
+ state = msi_desc[vector]->msi_attrib.state;
+ tail = msi_desc[vector]->link.tail;
+ base = msi_desc[vector]->mask_base;
spin_unlock_irqrestore(&msi_lock, flags);
- msi_free_vector(dev, i);
+ if (state)
+ warning = 1;
+ else if (vector != head) /* Release MSI-X vector */
+ msi_free_vector(dev, vector, 0);
+ vector = tail;
+ }
+ msi_free_vector(dev, vector, 0);
+ if (warning) {
+ /* Force to release the MSI-X memory-mapped table */
+ u32 phys_addr, table_offset;
+ u16 control;
+ u8 bir;
+
+ pci_read_config_word(dev, msi_control_reg(pos),
+ &control);
+ pci_read_config_dword(dev, msix_table_offset_reg(pos),
+ &table_offset);
+ bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
+ phys_addr = pci_resource_start (dev, bir);
+ phys_addr += (u32)(table_offset &
+ ~PCI_MSIX_FLAGS_BIRMASK);
+ iounmap((void*)base);
+ release_mem_region(phys_addr, PCI_MSIX_ENTRY_SIZE *
+ multi_msix_capable(control));
+ printk(KERN_DEBUG "Driver[%d:%d:%d] unloaded wo doing free_irq on all vectors\n",
+ dev->bus->number, PCI_SLOT(dev->devfn),
+ PCI_FUNC(dev->devfn));
+ BUG_ON(warning > 0);
}
- writel(1, entry->mask_base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
- iounmap((void*)entry->mask_base);
- release_mem_region(phys_addr, dev_msi_cap * PCI_MSIX_ENTRY_SIZE);
+ dev->irq = temp; /* Restore IOAPIC IRQ */
}
- dev->irq = temp;
- nr_reserved_vectors++;
}
EXPORT_SYMBOL(pci_enable_msi);
-EXPORT_SYMBOL(msi_alloc_vectors);
-EXPORT_SYMBOL(msi_free_vectors);
+EXPORT_SYMBOL(pci_disable_msi);
+EXPORT_SYMBOL(pci_enable_msix);
+EXPORT_SYMBOL(pci_disable_msix);
diff -urN linux-2.6.7/drivers/pci/msi.h patch-2.6.7-fix-msix/drivers/pci/msi.h
--- linux-2.6.7/drivers/pci/msi.h 2004-05-09 22:32:53.000000000 -0400
+++ patch-2.6.7-fix-msix/drivers/pci/msi.h 2004-06-25 14:44:08.000000000 -0400
@@ -140,7 +140,8 @@
struct {
__u8 type : 5; /* {0: unused, 5h:MSI, 11h:MSI-X} */
__u8 maskbit : 1; /* mask-pending bit supported ? */
- __u8 reserved: 2; /* reserved */
+ __u8 state : 1; /* {0: free, 1: busy} */
+ __u8 reserved: 1; /* reserved */
__u8 entry_nr; /* specific enabled entry */
__u8 default_vector; /* default pre-assigned vector */
__u8 current_cpu; /* current destination cpu */
diff -urN linux-2.6.7/include/linux/pci.h patch-2.6.7-fix-msix/include/linux/pci.h
--- linux-2.6.7/include/linux/pci.h 2004-06-22 10:11:40.000000000 -0400
+++ patch-2.6.7-fix-msix/include/linux/pci.h 2004-06-25 14:50:49.000000000 -0400
@@ -786,16 +786,27 @@
extern struct pci_dev *isa_bridge;
#endif
+struct msix_entry {
+ u16 vector; /* kernel uses to write allocated vector */
+ u16 entry; /* driver uses to specify entry, OS writes */
+};
+
#ifndef CONFIG_PCI_USE_VECTOR
static inline void pci_scan_msi_device(struct pci_dev *dev) {}
static inline int pci_enable_msi(struct pci_dev *dev) {return -1;}
+static inline void pci_disable_msi(struct pci_dev *dev) {}
+static inline int pci_enable_msix(struct pci_dev* dev,
+ struct msix_entry *entries, int nvec) {return -1;}
+static inline void pci_disable_msix(struct pci_dev *dev) {}
static inline void msi_remove_pci_irq_vectors(struct pci_dev *dev) {}
#else
extern void pci_scan_msi_device(struct pci_dev *dev);
extern int pci_enable_msi(struct pci_dev *dev);
+extern void pci_disable_msi(struct pci_dev *dev);
+extern int pci_enable_msix(struct pci_dev* dev,
+ struct msix_entry *entries, int nvec);
+extern void pci_disable_msix(struct pci_dev *dev);
extern void msi_remove_pci_irq_vectors(struct pci_dev *dev);
-extern int msi_alloc_vectors(struct pci_dev* dev, int *vector, int nvec);
-extern int msi_free_vectors(struct pci_dev* dev, int *vector, int nvec);
#endif
#endif /* CONFIG_PCI */
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2004-07-18 1:27 UTC | newest]
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2004-07-13 22:02 Re:[PATCH]2.6.7 MSI-X Update long
2004-07-15 2:14 ` [PATCH]2.6.7 " Roland Dreier
2004-07-18 1:25 ` Roland Dreier
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2004-06-26 1:21 long
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