Re: [PATCH] usb: enable pci MSI/MSIX in usb core

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Sarah Sharp]

On Tue, Feb 07, 2012 at 06:42:04AM -0800, Greg KH wrote:
> On Tue, Feb 07, 2012 at 07:59:47PM +0800, Alex Shi wrote:
> > On 02/06/2012 08:29 PM, Alex Shi wrote:
> > 
> > > MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
> > > be used more and more in future, but current USB core still just wants
> > > line IRQ, only XHCI usb driver enabled MSI/MSIX.
> > > 
> > > This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
> > > setup code from XHCI since it becomes redundant now.
> > > There 2 places need prepare to enable MSI/MSIX in usb driver.
> > > 1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
> > > 2, prepare a get_msix_num() for specific drivers.
> > > XHCI is a good example for this.
> > > 
> > > This patch bases on my "USB-try-MSI-before-legacy-irq-on-pci-xhci-HCD"
> > > patch.
> > 
> > 
> > Gregkh&Alan:
> > 
> > Do you need a full patch that include my recent MSI setup/bug fix
> > patches? or just this one is ok?
> 
> I was thinking that Sarah would forward this on.  We need whatever
> should be applied to the tree, as I do not have any pending patches from
> you in my queue.

I'm trying to track down an oops on my for-usb-linus queue that could
either be related to Alex's original MSI work around patch, or the patch
Oliver posted for working around PCI MMIO not being enabled fast enough.
I don't want to review this MSI improvement patch until I'm sure the
original MSI work around patch is stable.

Alex, please give me time to debug bug fixes for 3.3 before pushing on
features for 3.4.

Sarah Sharp

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Sarah Sharp]

On Tue, Feb 07, 2012 at 09:27:43AM -0800, Sarah Sharp wrote:
> I'm trying to track down an oops on my for-usb-linus queue that could
> either be related to Alex's original MSI work around patch, or the patch
> Oliver posted for working around PCI MMIO not being enabled fast enough.
> I don't want to review this MSI improvement patch until I'm sure the
> original MSI work around patch is stable.
> 
> Alex, please give me time to debug bug fixes for 3.3 before pushing on
> features for 3.4.

Alex, your original MSI enabling patch simply does not work.  The xHCI
PCI driver was marked as const and the xHCI PCI probe function oopsed as
soon as it tried to add HCD_MSI_FIRST to driver->flags.  Please test all
the patches in your patchsets individually to make sure they don't cause
bugs, as this will break git-bisect.  It's especially troublesome to not
test a patch I've said will be needed for stable, since we really try
not to break stable. </grumpy maintainer rant>

The oops brings up an interesting point.  I think the reason the xHCI
PCI driver structure is marked as const is because it's shared across
all xHCI hosts in the system.  Even if you remove the const keyword, you
could be modifying the flags while another xHCI host controller is being
initialized.

I think PCI probe isn't run in parallel, but you could still have the
case where the Intel Panther Point xHCI PCI probe runs first,
HCD_MSI_FIRST gets added to the hcd driver flags, and then the PCI probe
runs for a Fresco Logic add-in card that doesn't handle MSI, and the USB
core doesn't attempt to allocate the legacy IRQ because HCD_MSI_FIRST is
set.  Then the Fresco Logic host controller will be left with no
interrupt.


Alan, is the hc_driver structure (xhci_pci_hc_driver) shared across all
xHCI PCI hosts in the system?

Sarah Sharp

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

On Tue, 2012-02-07 at 14:13 -0800, Sarah Sharp wrote:
> On Tue, Feb 07, 2012 at 09:27:43AM -0800, Sarah Sharp wrote:
> > I'm trying to track down an oops on my for-usb-linus queue that could
> > either be related to Alex's original MSI work around patch, or the patch
> > Oliver posted for working around PCI MMIO not being enabled fast enough.
> > I don't want to review this MSI improvement patch until I'm sure the
> > original MSI work around patch is stable.
> > 
> > Alex, please give me time to debug bug fixes for 3.3 before pushing on
> > features for 3.4.
> 
> Alex, your original MSI enabling patch simply does not work.  The xHCI
> PCI driver was marked as const and the xHCI PCI probe function oopsed as
> soon as it tried to add HCD_MSI_FIRST to driver->flags.  Please test all
> the patches in your patchsets individually to make sure they don't cause
> bugs, as this will break git-bisect.  It's especially troublesome to not
> test a patch I've said will be needed for stable, since we really try
> not to break stable. </grumpy maintainer rant>

I am sorry for bring trouble on the patch. 
But all my patches were tested with possible USB3 HCD in our site,
include a NEC device and the BIOS broken Intel panther point HCD.

[    3.772513] xhci_hcd 0000:00:14.0: can't derive routing for PCI INT A
[    3.772515] xhci_hcd 0000:00:14.0: PCI INT A: no GSI
[    3.772552] xhci_hcd 0000:00:14.0: setting latency timer to 64
[    3.772593] xhci_hcd 0000:00:14.0: irq 45 for MSI/MSI-X
[    3.772602] xhci_hcd 0000:00:14.0: xHCI Host Controller
[    3.772639] xhci_hcd 0000:00:14.0: new USB bus registered, assigned
bus number 1

Maybe some kernel configuration related with this oops? 

> 
> The oops brings up an interesting point.  I think the reason the xHCI
> PCI driver structure is marked as const is because it's shared across
> all xHCI hosts in the system.  Even if you remove the const keyword, you
> could be modifying the flags while another xHCI host controller is being
> initialized.
> 
> I think PCI probe isn't run in parallel, but you could still have the
> case where the Intel Panther Point xHCI PCI probe runs first,
> HCD_MSI_FIRST gets added to the hcd driver flags, and then the PCI probe
> runs for a Fresco Logic add-in card that doesn't handle MSI, and the USB
> core doesn't attempt to allocate the legacy IRQ because HCD_MSI_FIRST is
> set.  Then the Fresco Logic host controller will be left with no
> interrupt.

Yes, you are right here.
So, the first patch naturally have this problem. But my latest patch:
enable MSI in usb-core won't the problem. Because it direct skip the
Fresco Card for MSI, not get help from flags. 

So, let's drop the previous 2 patches and using this latest one? 
> 
> 
> Alan, is the hc_driver structure (xhci_pci_hc_driver) shared across all
> xHCI PCI hosts in the system?
> 
> Sarah Sharp

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

> > 
> > The oops brings up an interesting point.  I think the reason the xHCI
> > PCI driver structure is marked as const is because it's shared across
> > all xHCI hosts in the system.  Even if you remove the const keyword, you
> > could be modifying the flags while another xHCI host controller is being
> > initialized.
> > 
> > I think PCI probe isn't run in parallel, but you could still have the
> > case where the Intel Panther Point xHCI PCI probe runs first,
> > HCD_MSI_FIRST gets added to the hcd driver flags, and then the PCI probe
> > runs for a Fresco Logic add-in card that doesn't handle MSI, and the USB
> > core doesn't attempt to allocate the legacy IRQ because HCD_MSI_FIRST is
> > set.  Then the Fresco Logic host controller will be left with no
> > interrupt.
> 
> Yes, you are right here.
> So, the first patch naturally have this problem. But my latest patch:
> enable MSI in usb-core won't the problem. Because it direct skip the
> Fresco Card for MSI, not get help from flags. 
> 
> So, let's drop the previous 2 patches and using this latest one? 

This following patch is base on Linus' tree and with a MSI bug fix on
kernel rebooting. 

As to the Intel buggy HCD work around patch in stable, we can also check
Fresco card in live, if the const problem can be resolved. 

----------
>From af0f01dec4477a5e7db533d8c28418b0f3d5326c Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@intel.com>
Date: Mon, 6 Feb 2012 19:47:15 +0800
Subject: [PATCH] usb: enable pci MSI/MSIX in usb core

MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
be used more and more in future, but current USB core still just wants
line IRQ, only XHCI usb driver enabled MSI/MSIX.

This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
setup code from XHCI since it becomes redundant now.
There 2 places need prepare to enable MSI/MSIX in usb driver.
1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
2, prepare a get_msix_num() for specific drivers.
XHCI is a good example for this.

Thanks for Sarah's effort on the MSI/MSIX enabling in XHCI. In fact most
of MSI/MSIX setup functions reuse from XHCI.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
 drivers/usb/core/hcd-pci.c  |  224 ++++++++++++++++++++++++++++++++++++++++++-
 drivers/usb/core/hcd.c      |   16 +++-
 drivers/usb/host/xhci-pci.c |   14 +--
 drivers/usb/host/xhci.c     |  211 +++-------------------------------------
 drivers/usb/host/xhci.h     |    5 +-
 include/linux/usb/hcd.h     |   15 +++
 6 files changed, 274 insertions(+), 211 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index d136b8f..c466ddc 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -153,6 +153,222 @@ static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
 
 /*-------------------------------------------------------------------------*/
 
+static int hcd_free_msix(struct usb_hcd *hcd)
+{
+	int i;
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (!hcd->msix_entries) {
+		printk(KERN_ERR "No msix entries found!\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < hcd->msix_count; i++)
+		if (hcd->msix_entries[i].vector)
+			free_irq(hcd->msix_entries[i].vector,
+					hcd);
+
+	pci_disable_msix(pdev);
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_enabled = 0;
+
+	return 0;
+}
+
+static int hcd_free_msi(struct usb_hcd *hcd)
+{
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (pdev->irq > 0)
+		free_irq(pdev->irq, hcd);
+
+	pci_disable_msi(pdev);
+	return 0;
+}
+
+/* Free and disable msi/msix */
+void usb_hcd_free_msi_msix(struct usb_hcd *hcd)
+{
+	if (hcd->msix_entries)
+		hcd_free_msix(hcd);
+	else
+		hcd_free_msi(hcd);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_free_msi_msix);
+
+void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd)
+{
+	int i;
+	if (hcd->msix_entries) {
+		for (i = 0; i < hcd->msix_count; i++)
+			synchronize_irq(hcd->msix_entries[i].vector);
+	}
+
+}
+EXPORT_SYMBOL_GPL(usb_hcd_msix_sync_irqs);
+
+/*
+ * Set up MSI
+ */
+static int hcd_setup_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	ret = pci_enable_msi(pdev);
+	if (ret)
+		dev_dbg(&pdev->dev, "failed to allocate MSI entry\n");
+	return ret;
+}
+
+/*
+ * Set up MSI-X
+ */
+static int hcd_setup_msix(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int i, ret = 0;
+
+	/*
+	 * calculate number of msi-x vectors supported.
+	 * Add additional 1 vector to ensure always available interrupt.
+	 */
+	hcd->msix_count = min((int)num_online_cpus() + 1,
+				hcd->driver->get_msix_num(hcd));
+
+	hcd->msix_entries =
+		kmalloc((sizeof(struct msix_entry))*hcd->msix_count,
+				GFP_KERNEL);
+	if (!hcd->msix_entries) {
+		dev_err(&pdev->dev, "Failed to allocate MSI-X entries\n");
+		hcd->msix_count = 0;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < hcd->msix_count; i++) {
+		hcd->msix_entries[i].entry = i;
+		hcd->msix_entries[i].vector = 0;
+	}
+
+	ret = pci_enable_msix(pdev, hcd->msix_entries, hcd->msix_count);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failed to enable MSI-X\n");
+		goto free_entries;
+	}
+
+	return ret;
+
+free_entries:
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_count = 0;
+	return ret;
+}
+
+/* Device for a quirk */
+#define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
+#define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
+
+/* Check for buggy HCD devices, and driver's expectation for MSI.
+ * Now, only xhci driver want it by HCD_MSI_FIRST setting. Other driver
+ * like ehci/uhci can follow this setting, if they want.
+ */
+static int hcd_no_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	if (pdev->vendor == PCI_VENDOR_ID_FRESCO_LOGIC &&
+			pdev->device == PCI_DEVICE_ID_FRESCO_LOGIC_PDK) {
+
+		/* Fresco Logic confirms: all revisions of this chip do not
+		 * support MSI, even though some of them claim to in their PCI
+		 * capabilities.
+		 */
+		dev_dbg(&pdev->dev, "QUIRK: Fresco Logic revision %u "
+				"has broken MSI implementation\n",
+				pdev->revision);
+		return 1;
+	} else if (!(hcd->driver->flags & HCD_MSI_FIRST))
+		return 1;
+
+	return 0;
+}
+
+/* setup msi/msix interrupts. if fails, fallback to line irq */
+static int hcd_setup_int(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	hcd->irq = -1;
+
+	if (!hcd_no_msi(pdev, hcd)) {
+
+		ret = hcd_setup_msix(pdev, hcd);
+		if (ret)
+			/* fall back to msi*/
+			ret = hcd_setup_msi(pdev, hcd);
+
+		if (!ret)
+			/* hcd->irq is -1, we have MSI */
+			return 0;
+	}
+
+	if (!pdev->irq) {
+		dev_err(&pdev->dev, "No msi or line irq found!\n");
+		return -1;
+	}
+	/* fallback to line irq */
+	hcd->irq = pdev->irq;
+	return 0;
+}
+
+/* msi irq handler should be here, if driver has */
+irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
+{
+	return hcd->driver->irq(hcd);
+}
+
+int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+					unsigned long irqflags)
+{
+	int retval = 1;
+	if (hcd->msix_entries && hcd->driver->irq) {
+		int i;
+		/* register hc_driver's irq handler */
+		for (i = 0; i < hcd->msix_count; i++) {
+			retval = request_irq(hcd->msix_entries[i].vector,
+					(irq_handler_t)hcd_msi_irq,
+					0, hcd->driver->description, hcd);
+			if (retval) {
+				hcd_free_msix(hcd);
+				break;
+			}
+		}
+		if (i == hcd->msix_count)
+			hcd->msix_enabled = 1;
+	} else if (hcd->irq == -1) {
+		/* use msi */
+		retval = request_irq(irqnum, (irq_handler_t)hcd_msi_irq,
+					0, hcd->driver->description, hcd);
+		if (retval)
+			hcd_free_msi(hcd);
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_request_msi_msix_irqs);
+
+/* setup msi/msix interrupts and requestion irqs for them */
+int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd)
+{
+	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
+	int ret = -1;
+
+	if (!hcd_setup_int(pdev, hcd))
+		ret = usb_hcd_request_msi_msix_irqs(hcd,
+				pdev->irq, IRQF_SHARED);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_register_msi_msix_irqs);
+
 /* configure so an HC device and id are always provided */
 /* always called with process context; sleeping is OK */
 
@@ -187,7 +403,8 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	if (!dev->irq) {
+	/* skip irq check if hcd wants MSI firstly. */
+	if (!(driver->flags & HCD_MSI_FIRST) && !dev->irq) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));
@@ -242,6 +459,11 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	pci_set_master(dev);
 
+	/* try enable MSI, if fail, seek line irq */
+	retval = hcd_setup_int(dev, hcd);
+	if (retval != 0)
+		goto unmap_registers;
+
 	retval = usb_add_hcd(hcd, dev->irq, IRQF_SHARED);
 	if (retval != 0)
 		goto unmap_registers;
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index eb19cba..579cbd3 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2322,7 +2322,7 @@ int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
 
-static int usb_hcd_request_irqs(struct usb_hcd *hcd,
+static int usb_hcd_request_default_irqs(struct usb_hcd *hcd,
 		unsigned int irqnum, unsigned long irqflags)
 {
 	int retval;
@@ -2362,6 +2362,20 @@ static int usb_hcd_request_irqs(struct usb_hcd *hcd,
 	return 0;
 }
 
+int usb_hcd_request_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+		unsigned long irqflags)
+{
+	int retval = 1;
+
+#ifdef CONFIG_PCI
+	retval = usb_hcd_request_msi_msix_irqs(hcd, irqnum, irqflags);
+#endif
+	if (retval)
+		retval = usb_hcd_request_default_irqs(hcd, irqnum, irqflags);
+
+	return retval;
+}
+
 /**
  * usb_add_hcd - finish generic HCD structure initialization and register
  * @hcd: the usb_hcd structure to initialize
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ef98b38..ec44180 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -64,14 +64,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 			xhci_dbg(xhci, "QUIRK: Fresco Logic xHC needs configure"
 					" endpoint cmd after reset endpoint\n");
 		}
-		/* Fresco Logic confirms: all revisions of this chip do not
-		 * support MSI, even though some of them claim to in their PCI
-		 * capabilities.
-		 */
-		xhci->quirks |= XHCI_BROKEN_MSI;
-		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
-				"has broken MSI implementation\n",
-				pdev->revision);
 	}
 
 	if (pdev->vendor == PCI_VENDOR_ID_NEC)
@@ -124,6 +116,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
 	return retval;
 }
 
+
 /*
  * We need to register our own PCI probe function (instead of the USB core's
  * function) in order to create a second roothub under xHCI.
@@ -136,6 +129,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	struct usb_hcd *hcd;
 
 	driver = (struct hc_driver *)id->driver_data;
+
 	/* Register the USB 2.0 roothub.
 	 * FIXME: USB core must know to register the USB 2.0 roothub first.
 	 * This is sort of silly, because we could just set the HCD driver flags
@@ -243,13 +237,15 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	 * generic hardware linkage
 	 */
 	.irq =			xhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED |
+				HCD_MSI_FIRST,
 
 	/*
 	 * basic lifecycle operations
 	 */
 	.reset =		xhci_pci_setup,
 	.start =		xhci_run,
+	.get_msix_num =		xhci_get_msix_num,
 #ifdef CONFIG_PM
 	.pci_suspend =          xhci_pci_suspend,
 	.pci_resume =           xhci_pci_resume,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6bbe3c3..00cf296 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -176,205 +176,24 @@ int xhci_reset(struct xhci_hcd *xhci)
 }
 
 #ifdef CONFIG_PCI
-static int xhci_free_msi(struct xhci_hcd *xhci)
-{
-	int i;
-
-	if (!xhci->msix_entries)
-		return -EINVAL;
-
-	for (i = 0; i < xhci->msix_count; i++)
-		if (xhci->msix_entries[i].vector)
-			free_irq(xhci->msix_entries[i].vector,
-					xhci_to_hcd(xhci));
-	return 0;
-}
-
-/*
- * Set up MSI
- */
-static int xhci_setup_msi(struct xhci_hcd *xhci)
-{
-	int ret;
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-
-	ret = pci_enable_msi(pdev);
-	if (ret) {
-		xhci_dbg(xhci, "failed to allocate MSI entry\n");
-		return ret;
-	}
-
-	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-	if (ret) {
-		xhci_dbg(xhci, "disable MSI interrupt\n");
-		pci_disable_msi(pdev);
-	}
-
-	return ret;
-}
-
-/*
- * Free IRQs
- * free all IRQs request
- */
-static void xhci_free_irq(struct xhci_hcd *xhci)
-{
-	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/* return if using legacy interrupt */
-	if (xhci_to_hcd(xhci)->irq >= 0)
-		return;
-
-	ret = xhci_free_msi(xhci);
-	if (!ret)
-		return;
-	if (pdev->irq >= 0)
-		free_irq(pdev->irq, xhci_to_hcd(xhci));
-
-	return;
-}
-
-/*
- * Set up MSI-X
- */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
-{
-	int i, ret = 0;
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	/*
-	 * calculate number of msi-x vectors supported.
-	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
-	 *   with max number of interrupters based on the xhci HCSPARAMS1.
-	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
-	 *   Add additional 1 vector to ensure always available interrupt.
-	 */
-	xhci->msix_count = min(num_online_cpus() + 1,
-				HCS_MAX_INTRS(xhci->hcs_params1));
-
-	xhci->msix_entries =
-		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
-				GFP_KERNEL);
-	if (!xhci->msix_entries) {
-		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		xhci->msix_entries[i].entry = i;
-		xhci->msix_entries[i].vector = 0;
-	}
-
-	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
-	if (ret) {
-		xhci_dbg(xhci, "Failed to enable MSI-X\n");
-		goto free_entries;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		ret = request_irq(xhci->msix_entries[i].vector,
-				(irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-		if (ret)
-			goto disable_msix;
-	}
-
-	hcd->msix_enabled = 1;
-	return ret;
-
-disable_msix:
-	xhci_dbg(xhci, "disable MSI-X interrupt\n");
-	xhci_free_irq(xhci);
-	pci_disable_msix(pdev);
-free_entries:
-	kfree(xhci->msix_entries);
-	xhci->msix_entries = NULL;
-	return ret;
-}
-
-/* Free any IRQs and disable MSI-X */
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	xhci_free_irq(xhci);
-
-	if (xhci->msix_entries) {
-		pci_disable_msix(pdev);
-		kfree(xhci->msix_entries);
-		xhci->msix_entries = NULL;
-	} else {
-		pci_disable_msi(pdev);
-	}
-
-	hcd->msix_enabled = 0;
-	return;
-}
 
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
-	int i;
-
-	if (xhci->msix_entries) {
-		for (i = 0; i < xhci->msix_count; i++)
-			synchronize_irq(xhci->msix_entries[i].vector);
-	}
+	usb_hcd_msix_sync_irqs(xhci_to_hcd(xhci));
 }
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
+/* called in interrupt setup during pci probe() */
+int xhci_get_msix_num(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
 
-	/*
-	 * Some Fresco Logic host controllers advertise MSI, but fail to
-	 * generate interrupts.  Don't even try to enable MSI.
-	 */
-	if (xhci->quirks & XHCI_BROKEN_MSI)
-		return 0;
-
-	/* unregister the legacy interrupt */
-	if (hcd->irq)
-		free_irq(hcd->irq, hcd);
-	hcd->irq = -1;
-
-	ret = xhci_setup_msix(xhci);
-	if (ret)
-		/* fall back to msi*/
-		ret = xhci_setup_msi(xhci);
-
-	if (!ret)
-		/* hcd->irq is -1, we have MSI */
-		return 0;
-
-	/* fall back to legacy interrupt*/
-	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
-			hcd->irq_descr, hcd);
-	if (ret) {
-		xhci_err(xhci, "request interrupt %d failed\n",
-				pdev->irq);
-		return ret;
-	}
-	hcd->irq = pdev->irq;
-	return 0;
+	/* danger: xhci may be null, but it's useless in xhci_readl() now */
+	return HCS_MAX_INTRS(xhci_readl(xhci,
+		&((struct xhci_cap_regs *)hcd->regs)->hcs_params1));
 }
 
 #else
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
-{
-	return 0;
-}
-
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-}
-
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
 }
@@ -406,7 +225,6 @@ int xhci_init(struct usb_hcd *hcd)
 
 	return retval;
 }
-
 /*-------------------------------------------------------------------------*/
 
 
@@ -492,7 +310,6 @@ int xhci_run(struct usb_hcd *hcd)
 {
 	u32 temp;
 	u64 temp_64;
-	int ret;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
 	/* Start the xHCI host controller running only after the USB 2.0 roothub
@@ -505,10 +322,6 @@ int xhci_run(struct usb_hcd *hcd)
 
 	xhci_dbg(xhci, "xhci_run\n");
 
-	ret = xhci_try_enable_msi(hcd);
-	if (ret)
-		return ret;
-
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	init_timer(&xhci->event_ring_timer);
 	xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -604,7 +417,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_reset(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	/* Tell the event ring poll function not to reschedule */
@@ -646,7 +459,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_halt(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
 		    xhci_readl(xhci, &xhci->op_regs->status));
@@ -848,7 +661,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		xhci_halt(xhci);
 		xhci_reset(xhci);
 		spin_unlock_irq(&xhci->lock);
-		xhci_cleanup_msix(xhci);
+		usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 		/* Tell the event ring poll function not to reschedule */
@@ -883,7 +696,11 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		if (retval)
 			return retval;
 		xhci_dbg(xhci, "Start the primary HCD\n");
-		retval = xhci_run(hcd->primary_hcd);
+		if (dev_is_pci(hcd->self.controller))
+			retval = usb_hcd_register_msi_msix_irqs(
+						hcd->primary_hcd);
+		if (!retval)
+			retval = xhci_run(hcd->primary_hcd);
 		if (!retval) {
 			xhci_dbg(xhci, "Start the secondary HCD\n");
 			retval = xhci_run(secondary_hcd);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fb99c83..8d511dd 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1388,9 +1388,6 @@ struct xhci_hcd {
 	int		page_size;
 	/* Valid values are 12 to 20, inclusive */
 	int		page_shift;
-	/* msi-x vectors */
-	int		msix_count;
-	struct msix_entry	*msix_entries;
 	/* data structures */
 	struct xhci_device_context_array *dcbaa;
 	struct xhci_ring	*cmd_ring;
@@ -1643,9 +1640,11 @@ void xhci_free_command(struct xhci_hcd *xhci,
 /* xHCI PCI glue */
 int xhci_register_pci(void);
 void xhci_unregister_pci(void);
+int xhci_get_msix_num(struct usb_hcd *hcd);
 #else
 static inline int xhci_register_pci(void) { return 0; }
 static inline void xhci_unregister_pci(void) {}
+static inline int xhci_get_msix_num(struct usb_hcd *hcd) { return 0; }
 #endif
 
 /* xHCI host controller glue */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index b2f62f3..1f2df75 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -22,6 +22,7 @@
 #ifdef __KERNEL__
 
 #include <linux/rwsem.h>
+#include <linux/pci.h>		/* for struct msix_entry */
 
 #define MAX_TOPO_LEVEL		6
 
@@ -133,6 +134,12 @@ struct usb_hcd {
 	u64			rsrc_len;	/* memory/io resource length */
 	unsigned		power_budget;	/* in mA, 0 = no limit */
 
+#ifdef CONFIG_PCI
+	/* msi-x vectors */
+	int			msix_count;
+	struct msix_entry	*msix_entries;
+#endif
+
 	/* bandwidth_mutex should be taken before adding or removing
 	 * any new bus bandwidth constraints:
 	 *   1. Before adding a configuration for a new device.
@@ -210,6 +217,7 @@ struct hc_driver {
 #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
 #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
 #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
+#define	HCD_MSI_FIRST	0x0008		/* Try to get MSI first, PCI only */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
 #define	HCD_USB3	0x0040		/* USB 3.0 */
@@ -218,6 +226,7 @@ struct hc_driver {
 	/* called to init HCD and root hub */
 	int	(*reset) (struct usb_hcd *hcd);
 	int	(*start) (struct usb_hcd *hcd);
+	int	(*get_msix_num) (struct usb_hcd *hcd);
 
 	/* NOTE:  these suspend/resume calls relate to the HC as
 	 * a whole, not just the root hub; they're for PCI bus glue.
@@ -393,6 +402,12 @@ extern int usb_hcd_pci_probe(struct pci_dev *dev,
 extern void usb_hcd_pci_remove(struct pci_dev *dev);
 extern void usb_hcd_pci_shutdown(struct pci_dev *dev);
 
+extern void usb_hcd_free_msi_msix(struct usb_hcd *hcd);
+extern void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd);
+extern int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd,
+		unsigned int irqnum, unsigned long irqflags);
+extern int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd);
+
 #ifdef CONFIG_PM_SLEEP
 extern const struct dev_pm_ops usb_hcd_pci_pm_ops;
 #endif
-- 
1.6.3.3

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

On Wed, 2012-02-08 at 14:27 +0800, Alex,Shi wrote:
> > > 
> > > The oops brings up an interesting point.  I think the reason the xHCI
> > > PCI driver structure is marked as const is because it's shared across
> > > all xHCI hosts in the system.  Even if you remove the const keyword, you
> > > could be modifying the flags while another xHCI host controller is being
> > > initialized.
> > > 
> > > I think PCI probe isn't run in parallel, but you could still have the
> > > case where the Intel Panther Point xHCI PCI probe runs first,
> > > HCD_MSI_FIRST gets added to the hcd driver flags, and then the PCI probe
> > > runs for a Fresco Logic add-in card that doesn't handle MSI, and the USB
> > > core doesn't attempt to allocate the legacy IRQ because HCD_MSI_FIRST is
> > > set.  Then the Fresco Logic host controller will be left with no
> > > interrupt.
> > 
> > Yes, you are right here.
> > So, the first patch naturally have this problem. But my latest patch:
> > enable MSI in usb-core won't the problem. Because it direct skip the
> > Fresco Card for MSI, not get help from flags. 
> > 
> > So, let's drop the previous 2 patches and using this latest one? 
> 
> This following patch is base on Linus' tree and with a MSI bug fix on
> kernel rebooting. 
> 
> As to the Intel buggy HCD work around patch in stable, we can also check
> Fresco card in live, if the const problem can be resolved.

A potential bug fix for my latest patch, the line irq can not be freed
in suspend, since resume don't core it. 

--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -179,7 +179,7 @@ static int hcd_free_msi(struct usb_hcd *hcd)
 {
        struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
 
-       if (pdev->irq > 0)
+       if (pdev->irq > 0 && hcd->irq < 0) 
                free_irq(pdev->irq, hcd);
 
        pci_disable_msi(pdev);


Refresh patch that include above change as below
------------------------
>From 441a8d8621558f877e57d0b7b1b84c05ffd2d723 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@intel.com>
Date: Mon, 6 Feb 2012 19:47:15 +0800
Subject: [PATCH] usb: enable pci MSI/MSIX in usb core

MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
be used more and more in future, but current USB core still just wants
line IRQ, only XHCI usb driver enabled MSI/MSIX.

This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
setup code from XHCI since it becomes redundant now.
There 2 places need prepare to enable MSI/MSIX in usb driver.
1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
2, prepare a get_msix_num() for specific drivers.
XHCI is a good example for this.

Thanks for Sarah's effort on the MSI/MSIX enabling in XHCI. In fact most
of MSI/MSIX setup functions reuse from XHCI.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
 drivers/usb/core/hcd-pci.c  |  224 ++++++++++++++++++++++++++++++++++++++++++-
 drivers/usb/core/hcd.c      |   16 +++-
 drivers/usb/host/xhci-pci.c |   14 +--
 drivers/usb/host/xhci.c     |  211 +++-------------------------------------
 drivers/usb/host/xhci.h     |    5 +-
 include/linux/usb/hcd.h     |   15 +++
 6 files changed, 274 insertions(+), 211 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index d136b8f..2b4d80b 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -153,6 +153,222 @@ static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
 
 /*-------------------------------------------------------------------------*/
 
+static int hcd_free_msix(struct usb_hcd *hcd)
+{
+	int i;
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (!hcd->msix_entries) {
+		printk(KERN_ERR "No msix entries found!\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < hcd->msix_count; i++)
+		if (hcd->msix_entries[i].vector)
+			free_irq(hcd->msix_entries[i].vector,
+					hcd);
+
+	pci_disable_msix(pdev);
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_enabled = 0;
+
+	return 0;
+}
+
+static int hcd_free_msi(struct usb_hcd *hcd)
+{
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (pdev->irq > 0 && hcd->irq < 0)
+		free_irq(pdev->irq, hcd);
+
+	pci_disable_msi(pdev);
+	return 0;
+}
+
+/* Free and disable msi/msix */
+void usb_hcd_free_msi_msix(struct usb_hcd *hcd)
+{
+	if (hcd->msix_entries)
+		hcd_free_msix(hcd);
+	else
+		hcd_free_msi(hcd);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_free_msi_msix);
+
+void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd)
+{
+	int i;
+	if (hcd->msix_entries) {
+		for (i = 0; i < hcd->msix_count; i++)
+			synchronize_irq(hcd->msix_entries[i].vector);
+	}
+
+}
+EXPORT_SYMBOL_GPL(usb_hcd_msix_sync_irqs);
+
+/*
+ * Set up MSI
+ */
+static int hcd_setup_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	ret = pci_enable_msi(pdev);
+	if (ret)
+		dev_dbg(&pdev->dev, "failed to allocate MSI entry\n");
+	return ret;
+}
+
+/*
+ * Set up MSI-X
+ */
+static int hcd_setup_msix(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int i, ret = 0;
+
+	/*
+	 * calculate number of msi-x vectors supported.
+	 * Add additional 1 vector to ensure always available interrupt.
+	 */
+	hcd->msix_count = min((int)num_online_cpus() + 1,
+				hcd->driver->get_msix_num(hcd));
+
+	hcd->msix_entries =
+		kmalloc((sizeof(struct msix_entry))*hcd->msix_count,
+				GFP_KERNEL);
+	if (!hcd->msix_entries) {
+		dev_err(&pdev->dev, "Failed to allocate MSI-X entries\n");
+		hcd->msix_count = 0;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < hcd->msix_count; i++) {
+		hcd->msix_entries[i].entry = i;
+		hcd->msix_entries[i].vector = 0;
+	}
+
+	ret = pci_enable_msix(pdev, hcd->msix_entries, hcd->msix_count);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failed to enable MSI-X\n");
+		goto free_entries;
+	}
+
+	return ret;
+
+free_entries:
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_count = 0;
+	return ret;
+}
+
+/* Device for a quirk */
+#define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
+#define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
+
+/* Check for buggy HCD devices, and driver's expectation for MSI.
+ * Now, only xhci driver want it by HCD_MSI_FIRST setting. Other driver
+ * like ehci/uhci can follow this setting, if they want.
+ */
+static int hcd_no_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	if (pdev->vendor == PCI_VENDOR_ID_FRESCO_LOGIC &&
+			pdev->device == PCI_DEVICE_ID_FRESCO_LOGIC_PDK) {
+
+		/* Fresco Logic confirms: all revisions of this chip do not
+		 * support MSI, even though some of them claim to in their PCI
+		 * capabilities.
+		 */
+		dev_dbg(&pdev->dev, "QUIRK: Fresco Logic revision %u "
+				"has broken MSI implementation\n",
+				pdev->revision);
+		return 1;
+	} else if (!(hcd->driver->flags & HCD_MSI_FIRST))
+		return 1;
+
+	return 0;
+}
+
+/* setup msi/msix interrupts. if fails, fallback to line irq */
+static int hcd_setup_int(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	hcd->irq = -1;
+
+	if (!hcd_no_msi(pdev, hcd)) {
+
+		ret = hcd_setup_msix(pdev, hcd);
+		if (ret)
+			/* fall back to msi*/
+			ret = hcd_setup_msi(pdev, hcd);
+
+		if (!ret)
+			/* hcd->irq is -1, we have MSI */
+			return 0;
+	}
+
+	if (!pdev->irq) {
+		dev_err(&pdev->dev, "No msi or line irq found!\n");
+		return -1;
+	}
+	/* fallback to line irq */
+	hcd->irq = pdev->irq;
+	return 0;
+}
+
+/* msi irq handler should be here, if driver has */
+irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
+{
+	return hcd->driver->irq(hcd);
+}
+
+int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+					unsigned long irqflags)
+{
+	int retval = 1;
+	if (hcd->msix_entries && hcd->driver->irq) {
+		int i;
+		/* register hc_driver's irq handler */
+		for (i = 0; i < hcd->msix_count; i++) {
+			retval = request_irq(hcd->msix_entries[i].vector,
+					(irq_handler_t)hcd_msi_irq,
+					0, hcd->driver->description, hcd);
+			if (retval) {
+				hcd_free_msix(hcd);
+				break;
+			}
+		}
+		if (i == hcd->msix_count)
+			hcd->msix_enabled = 1;
+	} else if (hcd->irq == -1) {
+		/* use msi */
+		retval = request_irq(irqnum, (irq_handler_t)hcd_msi_irq,
+					0, hcd->driver->description, hcd);
+		if (retval)
+			hcd_free_msi(hcd);
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_request_msi_msix_irqs);
+
+/* setup msi/msix interrupts and requestion irqs for them */
+int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd)
+{
+	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
+	int ret = -1;
+
+	if (!hcd_setup_int(pdev, hcd))
+		ret = usb_hcd_request_msi_msix_irqs(hcd,
+				pdev->irq, IRQF_SHARED);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_register_msi_msix_irqs);
+
 /* configure so an HC device and id are always provided */
 /* always called with process context; sleeping is OK */
 
@@ -187,7 +403,8 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	if (!dev->irq) {
+	/* skip irq check if hcd wants MSI firstly. */
+	if (!(driver->flags & HCD_MSI_FIRST) && !dev->irq) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));
@@ -242,6 +459,11 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	pci_set_master(dev);
 
+	/* try enable MSI, if fail, seek line irq */
+	retval = hcd_setup_int(dev, hcd);
+	if (retval != 0)
+		goto unmap_registers;
+
 	retval = usb_add_hcd(hcd, dev->irq, IRQF_SHARED);
 	if (retval != 0)
 		goto unmap_registers;
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index eb19cba..579cbd3 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2322,7 +2322,7 @@ int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
 
-static int usb_hcd_request_irqs(struct usb_hcd *hcd,
+static int usb_hcd_request_default_irqs(struct usb_hcd *hcd,
 		unsigned int irqnum, unsigned long irqflags)
 {
 	int retval;
@@ -2362,6 +2362,20 @@ static int usb_hcd_request_irqs(struct usb_hcd *hcd,
 	return 0;
 }
 
+int usb_hcd_request_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+		unsigned long irqflags)
+{
+	int retval = 1;
+
+#ifdef CONFIG_PCI
+	retval = usb_hcd_request_msi_msix_irqs(hcd, irqnum, irqflags);
+#endif
+	if (retval)
+		retval = usb_hcd_request_default_irqs(hcd, irqnum, irqflags);
+
+	return retval;
+}
+
 /**
  * usb_add_hcd - finish generic HCD structure initialization and register
  * @hcd: the usb_hcd structure to initialize
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ef98b38..ec44180 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -64,14 +64,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 			xhci_dbg(xhci, "QUIRK: Fresco Logic xHC needs configure"
 					" endpoint cmd after reset endpoint\n");
 		}
-		/* Fresco Logic confirms: all revisions of this chip do not
-		 * support MSI, even though some of them claim to in their PCI
-		 * capabilities.
-		 */
-		xhci->quirks |= XHCI_BROKEN_MSI;
-		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
-				"has broken MSI implementation\n",
-				pdev->revision);
 	}
 
 	if (pdev->vendor == PCI_VENDOR_ID_NEC)
@@ -124,6 +116,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
 	return retval;
 }
 
+
 /*
  * We need to register our own PCI probe function (instead of the USB core's
  * function) in order to create a second roothub under xHCI.
@@ -136,6 +129,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	struct usb_hcd *hcd;
 
 	driver = (struct hc_driver *)id->driver_data;
+
 	/* Register the USB 2.0 roothub.
 	 * FIXME: USB core must know to register the USB 2.0 roothub first.
 	 * This is sort of silly, because we could just set the HCD driver flags
@@ -243,13 +237,15 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	 * generic hardware linkage
 	 */
 	.irq =			xhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED |
+				HCD_MSI_FIRST,
 
 	/*
 	 * basic lifecycle operations
 	 */
 	.reset =		xhci_pci_setup,
 	.start =		xhci_run,
+	.get_msix_num =		xhci_get_msix_num,
 #ifdef CONFIG_PM
 	.pci_suspend =          xhci_pci_suspend,
 	.pci_resume =           xhci_pci_resume,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6bbe3c3..00cf296 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -176,205 +176,24 @@ int xhci_reset(struct xhci_hcd *xhci)
 }
 
 #ifdef CONFIG_PCI
-static int xhci_free_msi(struct xhci_hcd *xhci)
-{
-	int i;
-
-	if (!xhci->msix_entries)
-		return -EINVAL;
-
-	for (i = 0; i < xhci->msix_count; i++)
-		if (xhci->msix_entries[i].vector)
-			free_irq(xhci->msix_entries[i].vector,
-					xhci_to_hcd(xhci));
-	return 0;
-}
-
-/*
- * Set up MSI
- */
-static int xhci_setup_msi(struct xhci_hcd *xhci)
-{
-	int ret;
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-
-	ret = pci_enable_msi(pdev);
-	if (ret) {
-		xhci_dbg(xhci, "failed to allocate MSI entry\n");
-		return ret;
-	}
-
-	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-	if (ret) {
-		xhci_dbg(xhci, "disable MSI interrupt\n");
-		pci_disable_msi(pdev);
-	}
-
-	return ret;
-}
-
-/*
- * Free IRQs
- * free all IRQs request
- */
-static void xhci_free_irq(struct xhci_hcd *xhci)
-{
-	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/* return if using legacy interrupt */
-	if (xhci_to_hcd(xhci)->irq >= 0)
-		return;
-
-	ret = xhci_free_msi(xhci);
-	if (!ret)
-		return;
-	if (pdev->irq >= 0)
-		free_irq(pdev->irq, xhci_to_hcd(xhci));
-
-	return;
-}
-
-/*
- * Set up MSI-X
- */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
-{
-	int i, ret = 0;
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	/*
-	 * calculate number of msi-x vectors supported.
-	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
-	 *   with max number of interrupters based on the xhci HCSPARAMS1.
-	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
-	 *   Add additional 1 vector to ensure always available interrupt.
-	 */
-	xhci->msix_count = min(num_online_cpus() + 1,
-				HCS_MAX_INTRS(xhci->hcs_params1));
-
-	xhci->msix_entries =
-		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
-				GFP_KERNEL);
-	if (!xhci->msix_entries) {
-		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		xhci->msix_entries[i].entry = i;
-		xhci->msix_entries[i].vector = 0;
-	}
-
-	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
-	if (ret) {
-		xhci_dbg(xhci, "Failed to enable MSI-X\n");
-		goto free_entries;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		ret = request_irq(xhci->msix_entries[i].vector,
-				(irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-		if (ret)
-			goto disable_msix;
-	}
-
-	hcd->msix_enabled = 1;
-	return ret;
-
-disable_msix:
-	xhci_dbg(xhci, "disable MSI-X interrupt\n");
-	xhci_free_irq(xhci);
-	pci_disable_msix(pdev);
-free_entries:
-	kfree(xhci->msix_entries);
-	xhci->msix_entries = NULL;
-	return ret;
-}
-
-/* Free any IRQs and disable MSI-X */
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	xhci_free_irq(xhci);
-
-	if (xhci->msix_entries) {
-		pci_disable_msix(pdev);
-		kfree(xhci->msix_entries);
-		xhci->msix_entries = NULL;
-	} else {
-		pci_disable_msi(pdev);
-	}
-
-	hcd->msix_enabled = 0;
-	return;
-}
 
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
-	int i;
-
-	if (xhci->msix_entries) {
-		for (i = 0; i < xhci->msix_count; i++)
-			synchronize_irq(xhci->msix_entries[i].vector);
-	}
+	usb_hcd_msix_sync_irqs(xhci_to_hcd(xhci));
 }
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
+/* called in interrupt setup during pci probe() */
+int xhci_get_msix_num(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
 
-	/*
-	 * Some Fresco Logic host controllers advertise MSI, but fail to
-	 * generate interrupts.  Don't even try to enable MSI.
-	 */
-	if (xhci->quirks & XHCI_BROKEN_MSI)
-		return 0;
-
-	/* unregister the legacy interrupt */
-	if (hcd->irq)
-		free_irq(hcd->irq, hcd);
-	hcd->irq = -1;
-
-	ret = xhci_setup_msix(xhci);
-	if (ret)
-		/* fall back to msi*/
-		ret = xhci_setup_msi(xhci);
-
-	if (!ret)
-		/* hcd->irq is -1, we have MSI */
-		return 0;
-
-	/* fall back to legacy interrupt*/
-	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
-			hcd->irq_descr, hcd);
-	if (ret) {
-		xhci_err(xhci, "request interrupt %d failed\n",
-				pdev->irq);
-		return ret;
-	}
-	hcd->irq = pdev->irq;
-	return 0;
+	/* danger: xhci may be null, but it's useless in xhci_readl() now */
+	return HCS_MAX_INTRS(xhci_readl(xhci,
+		&((struct xhci_cap_regs *)hcd->regs)->hcs_params1));
 }
 
 #else
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
-{
-	return 0;
-}
-
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-}
-
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
 }
@@ -406,7 +225,6 @@ int xhci_init(struct usb_hcd *hcd)
 
 	return retval;
 }
-
 /*-------------------------------------------------------------------------*/
 
 
@@ -492,7 +310,6 @@ int xhci_run(struct usb_hcd *hcd)
 {
 	u32 temp;
 	u64 temp_64;
-	int ret;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
 	/* Start the xHCI host controller running only after the USB 2.0 roothub
@@ -505,10 +322,6 @@ int xhci_run(struct usb_hcd *hcd)
 
 	xhci_dbg(xhci, "xhci_run\n");
 
-	ret = xhci_try_enable_msi(hcd);
-	if (ret)
-		return ret;
-
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	init_timer(&xhci->event_ring_timer);
 	xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -604,7 +417,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_reset(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	/* Tell the event ring poll function not to reschedule */
@@ -646,7 +459,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_halt(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
 		    xhci_readl(xhci, &xhci->op_regs->status));
@@ -848,7 +661,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		xhci_halt(xhci);
 		xhci_reset(xhci);
 		spin_unlock_irq(&xhci->lock);
-		xhci_cleanup_msix(xhci);
+		usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 		/* Tell the event ring poll function not to reschedule */
@@ -883,7 +696,11 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		if (retval)
 			return retval;
 		xhci_dbg(xhci, "Start the primary HCD\n");
-		retval = xhci_run(hcd->primary_hcd);
+		if (dev_is_pci(hcd->self.controller))
+			retval = usb_hcd_register_msi_msix_irqs(
+						hcd->primary_hcd);
+		if (!retval)
+			retval = xhci_run(hcd->primary_hcd);
 		if (!retval) {
 			xhci_dbg(xhci, "Start the secondary HCD\n");
 			retval = xhci_run(secondary_hcd);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fb99c83..8d511dd 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1388,9 +1388,6 @@ struct xhci_hcd {
 	int		page_size;
 	/* Valid values are 12 to 20, inclusive */
 	int		page_shift;
-	/* msi-x vectors */
-	int		msix_count;
-	struct msix_entry	*msix_entries;
 	/* data structures */
 	struct xhci_device_context_array *dcbaa;
 	struct xhci_ring	*cmd_ring;
@@ -1643,9 +1640,11 @@ void xhci_free_command(struct xhci_hcd *xhci,
 /* xHCI PCI glue */
 int xhci_register_pci(void);
 void xhci_unregister_pci(void);
+int xhci_get_msix_num(struct usb_hcd *hcd);
 #else
 static inline int xhci_register_pci(void) { return 0; }
 static inline void xhci_unregister_pci(void) {}
+static inline int xhci_get_msix_num(struct usb_hcd *hcd) { return 0; }
 #endif
 
 /* xHCI host controller glue */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index b2f62f3..1f2df75 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -22,6 +22,7 @@
 #ifdef __KERNEL__
 
 #include <linux/rwsem.h>
+#include <linux/pci.h>		/* for struct msix_entry */
 
 #define MAX_TOPO_LEVEL		6
 
@@ -133,6 +134,12 @@ struct usb_hcd {
 	u64			rsrc_len;	/* memory/io resource length */
 	unsigned		power_budget;	/* in mA, 0 = no limit */
 
+#ifdef CONFIG_PCI
+	/* msi-x vectors */
+	int			msix_count;
+	struct msix_entry	*msix_entries;
+#endif
+
 	/* bandwidth_mutex should be taken before adding or removing
 	 * any new bus bandwidth constraints:
 	 *   1. Before adding a configuration for a new device.
@@ -210,6 +217,7 @@ struct hc_driver {
 #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
 #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
 #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
+#define	HCD_MSI_FIRST	0x0008		/* Try to get MSI first, PCI only */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
 #define	HCD_USB3	0x0040		/* USB 3.0 */
@@ -218,6 +226,7 @@ struct hc_driver {
 	/* called to init HCD and root hub */
 	int	(*reset) (struct usb_hcd *hcd);
 	int	(*start) (struct usb_hcd *hcd);
+	int	(*get_msix_num) (struct usb_hcd *hcd);
 
 	/* NOTE:  these suspend/resume calls relate to the HC as
 	 * a whole, not just the root hub; they're for PCI bus glue.
@@ -393,6 +402,12 @@ extern int usb_hcd_pci_probe(struct pci_dev *dev,
 extern void usb_hcd_pci_remove(struct pci_dev *dev);
 extern void usb_hcd_pci_shutdown(struct pci_dev *dev);
 
+extern void usb_hcd_free_msi_msix(struct usb_hcd *hcd);
+extern void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd);
+extern int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd,
+		unsigned int irqnum, unsigned long irqflags);
+extern int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd);
+
 #ifdef CONFIG_PM_SLEEP
 extern const struct dev_pm_ops usb_hcd_pci_pm_ops;
 #endif
-- 
1.6.3.3

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Sarah Sharp]

On Wed, Feb 08, 2012 at 05:11:40PM +0800, Alex,Shi wrote:
> On Wed, 2012-02-08 at 14:27 +0800, Alex,Shi wrote:
> >From 441a8d8621558f877e57d0b7b1b84c05ffd2d723 Mon Sep 17 00:00:00 2001
> From: Alex Shi <alex.shi@intel.com>
> Date: Mon, 6 Feb 2012 19:47:15 +0800
> Subject: [PATCH] usb: enable pci MSI/MSIX in usb core
> 
> MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
> be used more and more in future, but current USB core still just wants
> line IRQ, only XHCI usb driver enabled MSI/MSIX.
> 
> This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
> setup code from XHCI since it becomes redundant now.
> There 2 places need prepare to enable MSI/MSIX in usb driver.
> 1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
> 2, prepare a get_msix_num() for specific drivers.
> XHCI is a good example for this.
>
> Thanks for Sarah's effort on the MSI/MSIX enabling in XHCI. In fact most
> of MSI/MSIX setup functions reuse from XHCI.
> 
> Signed-off-by: Alex Shi <alex.shi@intel.com>
> ---
>  drivers/usb/core/hcd-pci.c  |  224 ++++++++++++++++++++++++++++++++++++++++++-
>  drivers/usb/core/hcd.c      |   16 +++-
>  drivers/usb/host/xhci-pci.c |   14 +--
>  drivers/usb/host/xhci.c     |  211 +++-------------------------------------
>  drivers/usb/host/xhci.h     |    5 +-
>  include/linux/usb/hcd.h     |   15 +++
>  6 files changed, 274 insertions(+), 211 deletions(-)

Ugh, this is a giant patch.  It's too big for stable, and it adds new
host controller driver APIs.  We can't do that for stable.

I've come up with a much simpler solution for the stable patch, and I'll
send it to you shortly.  The rest is just comments on this patch
(although I don't have time today to finish reviewing the whole thing).

> 
> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> index d136b8f..2b4d80b 100644
> --- a/drivers/usb/core/hcd-pci.c
> +++ b/drivers/usb/core/hcd-pci.c
> @@ -153,6 +153,222 @@ static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
>  
>  /*-------------------------------------------------------------------------*/
>  
> +static int hcd_free_msix(struct usb_hcd *hcd)
> +{
> +	int i;
> +	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
> +
> +	if (!hcd->msix_entries) {
> +		printk(KERN_ERR "No msix entries found!\n");
> +		return -EINVAL;
> +	}
> +	for (i = 0; i < hcd->msix_count; i++)
> +		if (hcd->msix_entries[i].vector)
> +			free_irq(hcd->msix_entries[i].vector,
> +					hcd);
> +
> +	pci_disable_msix(pdev);
> +	kfree(hcd->msix_entries);
> +	hcd->msix_entries = NULL;
> +	hcd->msix_enabled = 0;
> +
> +	return 0;
> +}
> +
> +static int hcd_free_msi(struct usb_hcd *hcd)
> +{
> +	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
> +
> +	if (pdev->irq > 0 && hcd->irq < 0)
> +		free_irq(pdev->irq, hcd);
> +
> +	pci_disable_msi(pdev);
> +	return 0;
> +}
> +
> +/* Free and disable msi/msix */
> +void usb_hcd_free_msi_msix(struct usb_hcd *hcd)
> +{
> +	if (hcd->msix_entries)
> +		hcd_free_msix(hcd);
> +	else
> +		hcd_free_msi(hcd);
> +
> +	return;
> +}
> +EXPORT_SYMBOL_GPL(usb_hcd_free_msi_msix);
> +
> +void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd)
> +{
> +	int i;
> +	if (hcd->msix_entries) {
> +		for (i = 0; i < hcd->msix_count; i++)
> +			synchronize_irq(hcd->msix_entries[i].vector);
> +	}
> +
> +}
> +EXPORT_SYMBOL_GPL(usb_hcd_msix_sync_irqs);
> +
> +/*
> + * Set up MSI
> + */
> +static int hcd_setup_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
> +{
> +	int ret;
> +
> +	ret = pci_enable_msi(pdev);
> +	if (ret)
> +		dev_dbg(&pdev->dev, "failed to allocate MSI entry\n");
> +	return ret;
> +}
> +
> +/*
> + * Set up MSI-X
> + */
> +static int hcd_setup_msix(struct pci_dev *pdev, struct usb_hcd *hcd)
> +{
> +	int i, ret = 0;
> +
> +	/*
> +	 * calculate number of msi-x vectors supported.
> +	 * Add additional 1 vector to ensure always available interrupt.
> +	 */
> +	hcd->msix_count = min((int)num_online_cpus() + 1,
> +				hcd->driver->get_msix_num(hcd));
> +
> +	hcd->msix_entries =
> +		kmalloc((sizeof(struct msix_entry))*hcd->msix_count,
> +				GFP_KERNEL);
> +	if (!hcd->msix_entries) {
> +		dev_err(&pdev->dev, "Failed to allocate MSI-X entries\n");
> +		hcd->msix_count = 0;
> +		return -ENOMEM;
> +	}
> +
> +	for (i = 0; i < hcd->msix_count; i++) {
> +		hcd->msix_entries[i].entry = i;
> +		hcd->msix_entries[i].vector = 0;
> +	}
> +
> +	ret = pci_enable_msix(pdev, hcd->msix_entries, hcd->msix_count);
> +	if (ret) {
> +		dev_dbg(&pdev->dev, "Failed to enable MSI-X\n");
> +		goto free_entries;
> +	}
> +
> +	return ret;
> +
> +free_entries:
> +	kfree(hcd->msix_entries);
> +	hcd->msix_entries = NULL;
> +	hcd->msix_count = 0;
> +	return ret;
> +}
> +
> +/* Device for a quirk */
> +#define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
> +#define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
> +
> +/* Check for buggy HCD devices, and driver's expectation for MSI.
> + * Now, only xhci driver want it by HCD_MSI_FIRST setting. Other driver
> + * like ehci/uhci can follow this setting, if they want.
> + */
> +static int hcd_no_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
> +{
> +	if (pdev->vendor == PCI_VENDOR_ID_FRESCO_LOGIC &&
> +			pdev->device == PCI_DEVICE_ID_FRESCO_LOGIC_PDK) {
> +
> +		/* Fresco Logic confirms: all revisions of this chip do not
> +		 * support MSI, even though some of them claim to in their PCI
> +		 * capabilities.
> +		 */
> +		dev_dbg(&pdev->dev, "QUIRK: Fresco Logic revision %u "
> +				"has broken MSI implementation\n",
> +				pdev->revision);
> +		return 1;
> +	} else if (!(hcd->driver->flags & HCD_MSI_FIRST))
> +		return 1;

You don't need the else statement here, since you always return in the
previous if block.

> +
> +	return 0;
> +}
> +
> +/* setup msi/msix interrupts. if fails, fallback to line irq */
> +static int hcd_setup_int(struct pci_dev *pdev, struct usb_hcd *hcd)
> +{
> +	int ret;
> +
> +	hcd->irq = -1;
> +
> +	if (!hcd_no_msi(pdev, hcd)) {
> +
> +		ret = hcd_setup_msix(pdev, hcd);
> +		if (ret)
> +			/* fall back to msi*/
> +			ret = hcd_setup_msi(pdev, hcd);
> +
> +		if (!ret)
> +			/* hcd->irq is -1, we have MSI */
> +			return 0;
> +	}
> +
> +	if (!pdev->irq) {
> +		dev_err(&pdev->dev, "No msi or line irq found!\n");
> +		return -1;
> +	}
> +	/* fallback to line irq */
> +	hcd->irq = pdev->irq;
> +	return 0;
> +}
> +
> +/* msi irq handler should be here, if driver has */
> +irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
> +{
> +	return hcd->driver->irq(hcd);
> +}

This works for now, but it isn't going to work in the future.  We need
the USB core to provide us with the irq number so we can map the MSI-X
interrupt to the event ring that generated the interrupt, whenever we
get around to adding multiple event rings.

I think you need to add a new USB hcd callback for MSI/MSI-X vectors.  The
xHCI usb_hcd can provide both pointers.

> +int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
> +					unsigned long irqflags)
> +{
> +	int retval = 1;
> +	if (hcd->msix_entries && hcd->driver->irq) {
> +		int i;
> +		/* register hc_driver's irq handler */
> +		for (i = 0; i < hcd->msix_count; i++) {
> +			retval = request_irq(hcd->msix_entries[i].vector,
> +					(irq_handler_t)hcd_msi_irq,
> +					0, hcd->driver->description, hcd);
> +			if (retval) {
> +				hcd_free_msix(hcd);
> +				break;
> +			}
> +		}
> +		if (i == hcd->msix_count)
> +			hcd->msix_enabled = 1;
> +	} else if (hcd->irq == -1) {
> +		/* use msi */
> +		retval = request_irq(irqnum, (irq_handler_t)hcd_msi_irq,
> +					0, hcd->driver->description, hcd);
> +		if (retval)
> +			hcd_free_msi(hcd);
> +	}
> +
> +	return retval;
> +}
> +EXPORT_SYMBOL_GPL(usb_hcd_request_msi_msix_irqs);
> +
> +/* setup msi/msix interrupts and requestion irqs for them */
> +int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd)
> +{
> +	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
> +	int ret = -1;
> +
> +	if (!hcd_setup_int(pdev, hcd))
> +		ret = usb_hcd_request_msi_msix_irqs(hcd,
> +				pdev->irq, IRQF_SHARED);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_hcd_register_msi_msix_irqs);
> +
>  /* configure so an HC device and id are always provided */
>  /* always called with process context; sleeping is OK */
>  
> @@ -187,7 +403,8 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  		return -ENODEV;
>  	dev->current_state = PCI_D0;
>  
> -	if (!dev->irq) {
> +	/* skip irq check if hcd wants MSI firstly. */
> +	if (!(driver->flags & HCD_MSI_FIRST) && !dev->irq) {
>  		dev_err(&dev->dev,
>  			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
>  			pci_name(dev));
> @@ -242,6 +459,11 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  
>  	pci_set_master(dev);
>  
> +	/* try enable MSI, if fail, seek line irq */
> +	retval = hcd_setup_int(dev, hcd);
> +	if (retval != 0)
> +		goto unmap_registers;
> +
>  	retval = usb_add_hcd(hcd, dev->irq, IRQF_SHARED);
>  	if (retval != 0)
>  		goto unmap_registers;
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index eb19cba..579cbd3 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2322,7 +2322,7 @@ int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
>  }
>  EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
>  
> -static int usb_hcd_request_irqs(struct usb_hcd *hcd,
> +static int usb_hcd_request_default_irqs(struct usb_hcd *hcd,
>  		unsigned int irqnum, unsigned long irqflags)
>  {
>  	int retval;
> @@ -2362,6 +2362,20 @@ static int usb_hcd_request_irqs(struct usb_hcd *hcd,
>  	return 0;
>  }
>  
> +int usb_hcd_request_irqs(struct usb_hcd *hcd, unsigned int irqnum,
> +		unsigned long irqflags)
> +{
> +	int retval = 1;
> +
> +#ifdef CONFIG_PCI
> +	retval = usb_hcd_request_msi_msix_irqs(hcd, irqnum, irqflags);
> +#endif
> +	if (retval)
> +		retval = usb_hcd_request_default_irqs(hcd, irqnum, irqflags);
> +
> +	return retval;
> +}
> +
>  /**
>   * usb_add_hcd - finish generic HCD structure initialization and register
>   * @hcd: the usb_hcd structure to initialize
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index ef98b38..ec44180 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -64,14 +64,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
>  			xhci_dbg(xhci, "QUIRK: Fresco Logic xHC needs configure"
>  					" endpoint cmd after reset endpoint\n");
>  		}
> -		/* Fresco Logic confirms: all revisions of this chip do not
> -		 * support MSI, even though some of them claim to in their PCI
> -		 * capabilities.
> -		 */
> -		xhci->quirks |= XHCI_BROKEN_MSI;
> -		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
> -				"has broken MSI implementation\n",
> -				pdev->revision);
>  	}
>  
>  	if (pdev->vendor == PCI_VENDOR_ID_NEC)
> @@ -124,6 +116,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
>  	return retval;
>  }
>  
> +
>  /*
>   * We need to register our own PCI probe function (instead of the USB core's
>   * function) in order to create a second roothub under xHCI.
> @@ -136,6 +129,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  	struct usb_hcd *hcd;
>  
>  	driver = (struct hc_driver *)id->driver_data;
> +
>  	/* Register the USB 2.0 roothub.
>  	 * FIXME: USB core must know to register the USB 2.0 roothub first.
>  	 * This is sort of silly, because we could just set the HCD driver flags
> @@ -243,13 +237,15 @@ static const struct hc_driver xhci_pci_hc_driver = {
>  	 * generic hardware linkage
>  	 */
>  	.irq =			xhci_irq,
> -	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
> +	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED |
> +				HCD_MSI_FIRST,
>  
>  	/*
>  	 * basic lifecycle operations
>  	 */
>  	.reset =		xhci_pci_setup,
>  	.start =		xhci_run,
> +	.get_msix_num =		xhci_get_msix_num,
>  #ifdef CONFIG_PM
>  	.pci_suspend =          xhci_pci_suspend,
>  	.pci_resume =           xhci_pci_resume,
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 6bbe3c3..00cf296 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -176,205 +176,24 @@ int xhci_reset(struct xhci_hcd *xhci)
>  }
>  
>  #ifdef CONFIG_PCI
> -static int xhci_free_msi(struct xhci_hcd *xhci)
> -{
> -	int i;
> -
> -	if (!xhci->msix_entries)
> -		return -EINVAL;
> -
> -	for (i = 0; i < xhci->msix_count; i++)
> -		if (xhci->msix_entries[i].vector)
> -			free_irq(xhci->msix_entries[i].vector,
> -					xhci_to_hcd(xhci));
> -	return 0;
> -}
> -
> -/*
> - * Set up MSI
> - */
> -static int xhci_setup_msi(struct xhci_hcd *xhci)
> -{
> -	int ret;
> -	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
> -
> -	ret = pci_enable_msi(pdev);
> -	if (ret) {
> -		xhci_dbg(xhci, "failed to allocate MSI entry\n");
> -		return ret;
> -	}
> -
> -	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
> -				0, "xhci_hcd", xhci_to_hcd(xhci));
> -	if (ret) {
> -		xhci_dbg(xhci, "disable MSI interrupt\n");
> -		pci_disable_msi(pdev);
> -	}
> -
> -	return ret;
> -}
> -
> -/*
> - * Free IRQs
> - * free all IRQs request
> - */
> -static void xhci_free_irq(struct xhci_hcd *xhci)
> -{
> -	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
> -	int ret;
> -
> -	/* return if using legacy interrupt */
> -	if (xhci_to_hcd(xhci)->irq >= 0)
> -		return;
> -
> -	ret = xhci_free_msi(xhci);
> -	if (!ret)
> -		return;
> -	if (pdev->irq >= 0)
> -		free_irq(pdev->irq, xhci_to_hcd(xhci));
> -
> -	return;
> -}
> -
> -/*
> - * Set up MSI-X
> - */
> -static int xhci_setup_msix(struct xhci_hcd *xhci)
> -{
> -	int i, ret = 0;
> -	struct usb_hcd *hcd = xhci_to_hcd(xhci);
> -	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
> -
> -	/*
> -	 * calculate number of msi-x vectors supported.
> -	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
> -	 *   with max number of interrupters based on the xhci HCSPARAMS1.
> -	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
> -	 *   Add additional 1 vector to ensure always available interrupt.
> -	 */
> -	xhci->msix_count = min(num_online_cpus() + 1,
> -				HCS_MAX_INTRS(xhci->hcs_params1));
> -
> -	xhci->msix_entries =
> -		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
> -				GFP_KERNEL);
> -	if (!xhci->msix_entries) {
> -		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
> -		return -ENOMEM;
> -	}
> -
> -	for (i = 0; i < xhci->msix_count; i++) {
> -		xhci->msix_entries[i].entry = i;
> -		xhci->msix_entries[i].vector = 0;
> -	}
> -
> -	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
> -	if (ret) {
> -		xhci_dbg(xhci, "Failed to enable MSI-X\n");
> -		goto free_entries;
> -	}
> -
> -	for (i = 0; i < xhci->msix_count; i++) {
> -		ret = request_irq(xhci->msix_entries[i].vector,
> -				(irq_handler_t)xhci_msi_irq,
> -				0, "xhci_hcd", xhci_to_hcd(xhci));
> -		if (ret)
> -			goto disable_msix;
> -	}
> -
> -	hcd->msix_enabled = 1;
> -	return ret;
> -
> -disable_msix:
> -	xhci_dbg(xhci, "disable MSI-X interrupt\n");
> -	xhci_free_irq(xhci);
> -	pci_disable_msix(pdev);
> -free_entries:
> -	kfree(xhci->msix_entries);
> -	xhci->msix_entries = NULL;
> -	return ret;
> -}
> -
> -/* Free any IRQs and disable MSI-X */
> -static void xhci_cleanup_msix(struct xhci_hcd *xhci)
> -{
> -	struct usb_hcd *hcd = xhci_to_hcd(xhci);
> -	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
> -
> -	xhci_free_irq(xhci);
> -
> -	if (xhci->msix_entries) {
> -		pci_disable_msix(pdev);
> -		kfree(xhci->msix_entries);
> -		xhci->msix_entries = NULL;
> -	} else {
> -		pci_disable_msi(pdev);
> -	}
> -
> -	hcd->msix_enabled = 0;
> -	return;
> -}
>  
>  static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
>  {
> -	int i;
> -
> -	if (xhci->msix_entries) {
> -		for (i = 0; i < xhci->msix_count; i++)
> -			synchronize_irq(xhci->msix_entries[i].vector);
> -	}
> +	usb_hcd_msix_sync_irqs(xhci_to_hcd(xhci));
>  }
>  
> -static int xhci_try_enable_msi(struct usb_hcd *hcd)
> +/* called in interrupt setup during pci probe() */
> +int xhci_get_msix_num(struct usb_hcd *hcd)
>  {
>  	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> -	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
> -	int ret;
>  
> -	/*
> -	 * Some Fresco Logic host controllers advertise MSI, but fail to
> -	 * generate interrupts.  Don't even try to enable MSI.
> -	 */
> -	if (xhci->quirks & XHCI_BROKEN_MSI)
> -		return 0;
> -
> -	/* unregister the legacy interrupt */
> -	if (hcd->irq)
> -		free_irq(hcd->irq, hcd);
> -	hcd->irq = -1;
> -
> -	ret = xhci_setup_msix(xhci);
> -	if (ret)
> -		/* fall back to msi*/
> -		ret = xhci_setup_msi(xhci);
> -
> -	if (!ret)
> -		/* hcd->irq is -1, we have MSI */
> -		return 0;
> -
> -	/* fall back to legacy interrupt*/
> -	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
> -			hcd->irq_descr, hcd);
> -	if (ret) {
> -		xhci_err(xhci, "request interrupt %d failed\n",
> -				pdev->irq);
> -		return ret;
> -	}
> -	hcd->irq = pdev->irq;
> -	return 0;
> +	/* danger: xhci may be null, but it's useless in xhci_readl() now */
> +	return HCS_MAX_INTRS(xhci_readl(xhci,
> +		&((struct xhci_cap_regs *)hcd->regs)->hcs_params1));
>  }
>  
>  #else
>  
> -static int xhci_try_enable_msi(struct usb_hcd *hcd)
> -{
> -	return 0;
> -}
> -
> -static void xhci_cleanup_msix(struct xhci_hcd *xhci)
> -{
> -}
> -
>  static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
>  {
>  }
> @@ -406,7 +225,6 @@ int xhci_init(struct usb_hcd *hcd)
>  
>  	return retval;
>  }
> -
>  /*-------------------------------------------------------------------------*/
>  
>  
> @@ -492,7 +310,6 @@ int xhci_run(struct usb_hcd *hcd)
>  {
>  	u32 temp;
>  	u64 temp_64;
> -	int ret;
>  	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
>  
>  	/* Start the xHCI host controller running only after the USB 2.0 roothub
> @@ -505,10 +322,6 @@ int xhci_run(struct usb_hcd *hcd)
>  
>  	xhci_dbg(xhci, "xhci_run\n");
>  
> -	ret = xhci_try_enable_msi(hcd);
> -	if (ret)
> -		return ret;
> -
>  #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
>  	init_timer(&xhci->event_ring_timer);
>  	xhci->event_ring_timer.data = (unsigned long) xhci;
> @@ -604,7 +417,7 @@ void xhci_stop(struct usb_hcd *hcd)
>  	xhci_reset(xhci);
>  	spin_unlock_irq(&xhci->lock);
>  
> -	xhci_cleanup_msix(xhci);
> +	usb_hcd_free_msi_msix(hcd);
>  
>  #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
>  	/* Tell the event ring poll function not to reschedule */
> @@ -646,7 +459,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
>  	xhci_halt(xhci);
>  	spin_unlock_irq(&xhci->lock);
>  
> -	xhci_cleanup_msix(xhci);
> +	usb_hcd_free_msi_msix(hcd);
>  
>  	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
>  		    xhci_readl(xhci, &xhci->op_regs->status));
> @@ -848,7 +661,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
>  		xhci_halt(xhci);
>  		xhci_reset(xhci);
>  		spin_unlock_irq(&xhci->lock);
> -		xhci_cleanup_msix(xhci);
> +		usb_hcd_free_msi_msix(hcd);
>  
>  #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
>  		/* Tell the event ring poll function not to reschedule */
> @@ -883,7 +696,11 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
>  		if (retval)
>  			return retval;
>  		xhci_dbg(xhci, "Start the primary HCD\n");
> -		retval = xhci_run(hcd->primary_hcd);
> +		if (dev_is_pci(hcd->self.controller))
> +			retval = usb_hcd_register_msi_msix_irqs(
> +						hcd->primary_hcd);
> +		if (!retval)
> +			retval = xhci_run(hcd->primary_hcd);
>  		if (!retval) {
>  			xhci_dbg(xhci, "Start the secondary HCD\n");
>  			retval = xhci_run(secondary_hcd);
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index fb99c83..8d511dd 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1388,9 +1388,6 @@ struct xhci_hcd {
>  	int		page_size;
>  	/* Valid values are 12 to 20, inclusive */
>  	int		page_shift;
> -	/* msi-x vectors */
> -	int		msix_count;
> -	struct msix_entry	*msix_entries;
>  	/* data structures */
>  	struct xhci_device_context_array *dcbaa;
>  	struct xhci_ring	*cmd_ring;
> @@ -1643,9 +1640,11 @@ void xhci_free_command(struct xhci_hcd *xhci,
>  /* xHCI PCI glue */
>  int xhci_register_pci(void);
>  void xhci_unregister_pci(void);
> +int xhci_get_msix_num(struct usb_hcd *hcd);
>  #else
>  static inline int xhci_register_pci(void) { return 0; }
>  static inline void xhci_unregister_pci(void) {}
> +static inline int xhci_get_msix_num(struct usb_hcd *hcd) { return 0; }
>  #endif
>  
>  /* xHCI host controller glue */
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index b2f62f3..1f2df75 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -22,6 +22,7 @@
>  #ifdef __KERNEL__
>  
>  #include <linux/rwsem.h>
> +#include <linux/pci.h>		/* for struct msix_entry */
>  
>  #define MAX_TOPO_LEVEL		6
>  
> @@ -133,6 +134,12 @@ struct usb_hcd {
>  	u64			rsrc_len;	/* memory/io resource length */
>  	unsigned		power_budget;	/* in mA, 0 = no limit */
>  
> +#ifdef CONFIG_PCI
> +	/* msi-x vectors */
> +	int			msix_count;
> +	struct msix_entry	*msix_entries;
> +#endif
> +
>  	/* bandwidth_mutex should be taken before adding or removing
>  	 * any new bus bandwidth constraints:
>  	 *   1. Before adding a configuration for a new device.
> @@ -210,6 +217,7 @@ struct hc_driver {
>  #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
>  #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
>  #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
> +#define	HCD_MSI_FIRST	0x0008		/* Try to get MSI first, PCI only */
>  #define	HCD_USB11	0x0010		/* USB 1.1 */
>  #define	HCD_USB2	0x0020		/* USB 2.0 */
>  #define	HCD_USB3	0x0040		/* USB 3.0 */
> @@ -218,6 +226,7 @@ struct hc_driver {
>  	/* called to init HCD and root hub */
>  	int	(*reset) (struct usb_hcd *hcd);
>  	int	(*start) (struct usb_hcd *hcd);
> +	int	(*get_msix_num) (struct usb_hcd *hcd);
>  
>  	/* NOTE:  these suspend/resume calls relate to the HC as
>  	 * a whole, not just the root hub; they're for PCI bus glue.
> @@ -393,6 +402,12 @@ extern int usb_hcd_pci_probe(struct pci_dev *dev,
>  extern void usb_hcd_pci_remove(struct pci_dev *dev);
>  extern void usb_hcd_pci_shutdown(struct pci_dev *dev);
>  
> +extern void usb_hcd_free_msi_msix(struct usb_hcd *hcd);
> +extern void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd);
> +extern int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd,
> +		unsigned int irqnum, unsigned long irqflags);
> +extern int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd);
> +
>  #ifdef CONFIG_PM_SLEEP
>  extern const struct dev_pm_ops usb_hcd_pci_pm_ops;
>  #endif
> -- 
> 1.6.3.3
> 
> 
> 
> 

[RFT] USB: Try MSI first before line IRQ for Intel PCIe USB3 HCD

[Sarah Sharp]

We have a PCI USB xhci host controller on a new platform. It doesn't
have a line IRQ definition in BIOS. The Linux driver refuses to
initial this controller, but Windows works well because it only depends
on MSI.

Actually, Linux also can work for MSI. This patch skips the first line
IRQ checking for our HCD in usb-core pci probe, then try to enable MSI
firstly. That make this HCD works well under Linux.

This patch should be backported to kernels as old as 2.6.32.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
---

Hi Alex,

Please test this on your Panther Point system that doesn't have a BIOS
provided IRQ line.  I think this is a much simpler solution.

Sarah Sharp

 drivers/usb/core/hcd-pci.c |    5 ++++-
 drivers/usb/core/hcd.c     |    6 ++++--
 drivers/usb/host/xhci.c    |    5 +++++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index d136b8f..81e2c0d 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -187,7 +187,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	if (!dev->irq) {
+	/* The xHCI driver supports MSI and MSI-X,
+	 * so don't fail if the BIOS doesn't provide a legacy IRQ.
+	 */
+	if (!dev->irq && (driver->flags & HCD_MASK) != HCD_USB3) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index eb19cba..e128232 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2447,8 +2447,10 @@ int usb_add_hcd(struct usb_hcd *hcd,
 			&& device_can_wakeup(&hcd->self.root_hub->dev))
 		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
 
-	/* enable irqs just before we start the controller */
-	if (usb_hcd_is_primary_hcd(hcd)) {
+	/* enable irqs just before we start the controller,
+	 * if the BIOS provides legacy PCI irqs.
+	 */
+	if (usb_hcd_is_primary_hcd(hcd) && irqnum) {
 		retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
 		if (retval)
 			goto err_request_irq;
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6bbe3c3..c939f5f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -352,6 +352,11 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
 		/* hcd->irq is -1, we have MSI */
 		return 0;
 
+	if (!pdev->irq) {
+		xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
+		return -EINVAL;
+	}
+
 	/* fall back to legacy interrupt*/
 	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
 			hcd->irq_descr, hcd);
-- 
1.7.9

Re: [RFT] USB: Try MSI first before line IRQ for Intel PCIe USB3 HCD

[Alex,Shi]

On Mon, 2012-02-13 at 16:25 -0800, Sarah Sharp wrote:
> We have a PCI USB xhci host controller on a new platform. It doesn't
> have a line IRQ definition in BIOS. The Linux driver refuses to
> initial this controller, but Windows works well because it only depends
> on MSI.
> 
> Actually, Linux also can work for MSI. This patch skips the first line
> IRQ checking for our HCD in usb-core pci probe, then try to enable MSI
> firstly. That make this HCD works well under Linux.
> 
> This patch should be backported to kernels as old as 2.6.32.
> 
> Signed-off-by: Alex Shi <alex.shi@intel.com>
> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
> Cc: stable@vger.kernel.org
> ---
> 
> Hi Alex,
> 
> Please test this on your Panther Point system that doesn't have a BIOS
> provided IRQ line.  I think this is a much simpler solution.

It is Ok on the platform. 
Thanks!
> 
> Sarah Sharp
> 
>  drivers/usb/core/hcd-pci.c |    5 ++++-
>  drivers/usb/core/hcd.c     |    6 ++++--
>  drivers/usb/host/xhci.c    |    5 +++++
>  3 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> index d136b8f..81e2c0d 100644
> --- a/drivers/usb/core/hcd-pci.c
> +++ b/drivers/usb/core/hcd-pci.c
> @@ -187,7 +187,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  		return -ENODEV;
>  	dev->current_state = PCI_D0;
>  
> -	if (!dev->irq) {
> +	/* The xHCI driver supports MSI and MSI-X,
> +	 * so don't fail if the BIOS doesn't provide a legacy IRQ.
> +	 */
> +	if (!dev->irq && (driver->flags & HCD_MASK) != HCD_USB3) {
>  		dev_err(&dev->dev,
>  			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
>  			pci_name(dev));
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index eb19cba..e128232 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2447,8 +2447,10 @@ int usb_add_hcd(struct usb_hcd *hcd,
>  			&& device_can_wakeup(&hcd->self.root_hub->dev))
>  		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
>  
> -	/* enable irqs just before we start the controller */
> -	if (usb_hcd_is_primary_hcd(hcd)) {
> +	/* enable irqs just before we start the controller,
> +	 * if the BIOS provides legacy PCI irqs.
> +	 */
> +	if (usb_hcd_is_primary_hcd(hcd) && irqnum) {
>  		retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
>  		if (retval)
>  			goto err_request_irq;
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 6bbe3c3..c939f5f 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -352,6 +352,11 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
>  		/* hcd->irq is -1, we have MSI */
>  		return 0;
>  
> +	if (!pdev->irq) {
> +		xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
> +		return -EINVAL;
> +	}
> +
>  	/* fall back to legacy interrupt*/
>  	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
>  			hcd->irq_descr, hcd);

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

> Ugh, this is a giant patch.  It's too big for stable, and it adds new
> host controller driver APIs.  We can't do that for stable.

Yes, agree!
> > +		return 1;
> > +	} else if (!(hcd->driver->flags & HCD_MSI_FIRST))
> > +		return 1;
> 
> You don't need the else statement here, since you always return in the
> previous if block.

Correct! remove 'else' here make code more clear. 
> > +/* msi irq handler should be here, if driver has */
> > +irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
> > +{
> > +	return hcd->driver->irq(hcd);
> > +}
> 
> This works for now, but it isn't going to work in the future.  We need
> the USB core to provide us with the irq number so we can map the MSI-X
> interrupt to the event ring that generated the interrupt, whenever we
> get around to adding multiple event rings.
> 
> I think you need to add a new USB hcd callback for MSI/MSI-X vectors.  The
> xHCI usb_hcd can provide both pointers.
> 

Do you mean to add 2 new vectors for MSI/MSIX in hc_driver?
---
@@ -205,11 +212,14 @@ struct hc_driver {
 
        /* irq handler */
        irqreturn_t     (*irq) (struct usb_hcd *hcd);
+       irqreturn_t     (*msi_irq) (struct usb_hcd *hcd);
+       irqreturn_t     (*msix_irq) (struct usb_hcd *hcd);
 
        int     flags;
---
It is reasonable. When I written the code, I thought it may need
different MSI/MSIX irq handlers later for different driver. :) 

Actually, There is 2 ways to implement this vectors for detail. 
a, let driver's self code to do request_irq() for each of vectors for
MSI/MSIX, and hc_driver just has a simple hook for them.
b, do detailed request_irq() work in usb-core(in hcd-pci.c). 

Consider all pci MSI/MSIX interface is similar, we may prefer the second
way to save some code. 

What's opinions for above 2 ways? 

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

On Thu, 2012-02-16 at 10:36 +0800, Alex,Shi wrote:
> > Ugh, this is a giant patch.  It's too big for stable, and it adds new
> > host controller driver APIs.  We can't do that for stable.
> 
> Yes, agree!
> > > +		return 1;
> > > +	} else if (!(hcd->driver->flags & HCD_MSI_FIRST))
> > > +		return 1;
> > 
> > You don't need the else statement here, since you always return in the
> > previous if block.
> 
> Correct! remove 'else' here make code more clear. 
> > > +/* msi irq handler should be here, if driver has */
> > > +irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
> > > +{
> > > +	return hcd->driver->irq(hcd);
> > > +}
> > 
> > This works for now, but it isn't going to work in the future.  We need
> > the USB core to provide us with the irq number so we can map the MSI-X
> > interrupt to the event ring that generated the interrupt, whenever we
> > get around to adding multiple event rings.
> > 
> > I think you need to add a new USB hcd callback for MSI/MSI-X vectors.  The
> > xHCI usb_hcd can provide both pointers.
> > 
> 
> Do you mean to add 2 new vectors for MSI/MSIX in hc_driver?
> ---
> @@ -205,11 +212,14 @@ struct hc_driver {
>  
>         /* irq handler */
>         irqreturn_t     (*irq) (struct usb_hcd *hcd);
> +       irqreturn_t     (*msi_irq) (struct usb_hcd *hcd);
> +       irqreturn_t     (*msix_irq) (struct usb_hcd *hcd);
>  
>         int     flags;
> ---
> It is reasonable. When I written the code, I thought it may need
> different MSI/MSIX irq handlers later for different driver. :) 
> 
> Actually, There is 2 ways to implement this vectors for detail. 
> a, let driver's self code to do request_irq() for each of vectors for
> MSI/MSIX, and hc_driver just has a simple hook for them.
> b, do detailed request_irq() work in usb-core(in hcd-pci.c). 
> 
> Consider all pci MSI/MSIX interface is similar, we may prefer the second
> way to save some code. 
> 
> What's opinions for above 2 ways? 

I rewritten the patch base on your MSI bug fixing patch. and enhanced
with your comments. would you like review it again? 

============

>From 679cef4bfe8360f9f2851a0a1143a29dcbadcb44 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@intel.com>
Date: Fri, 17 Feb 2012 11:21:33 +0800
Subject: [PATCH v2] usb: enable pci MSI/MSIX in usb core

MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
be used more and more in future, but current USB core still just wants
line IRQ, only XHCI usb driver enabled MSI/MSIX.

This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
setup code from XHCI since it becomes redundant now.
There 3 places need prepare to enable MSI/MSIX in usb driver.
1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
2, prepare a get_msix_num() to get msix vector numb.
3, prepare msi/msix_irq handler if needed.

XHCI is a good example for this.

Thanks for Sarah's effort on the MSI/MSIX enabling in XHCI. In fact most
of MSI/MSIX setup functions reuse from XHCI.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
 drivers/usb/core/hcd-pci.c  |  223 ++++++++++++++++++++++++++++++++++++++++++-
 drivers/usb/core/hcd.c      |   16 +++-
 drivers/usb/host/xhci-pci.c |   16 ++--
 drivers/usb/host/xhci.c     |  216 +++---------------------------------------
 drivers/usb/host/xhci.h     |    5 +-
 include/linux/usb/hcd.h     |   17 ++++
 6 files changed, 274 insertions(+), 219 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 81e2c0d..8fab3c6 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -153,6 +153,218 @@ static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
 
 /*-------------------------------------------------------------------------*/
 
+static int hcd_free_msix(struct usb_hcd *hcd)
+{
+	int i;
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (!hcd->msix_entries) {
+		printk(KERN_ERR "No msix entries found!\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < hcd->msix_count; i++)
+		if (hcd->msix_entries[i].vector)
+			free_irq(hcd->msix_entries[i].vector,
+					hcd);
+
+	pci_disable_msix(pdev);
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_enabled = 0;
+
+	return 0;
+}
+
+static int hcd_free_msi(struct usb_hcd *hcd)
+{
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (pdev->irq > 0)
+		free_irq(pdev->irq, hcd);
+
+	pci_disable_msi(pdev);
+	return 0;
+}
+
+/* Free and disable msi/msix */
+void usb_hcd_free_msi_msix(struct usb_hcd *hcd)
+{
+	if (hcd->msix_entries)
+		hcd_free_msix(hcd);
+	else
+		hcd_free_msi(hcd);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_free_msi_msix);
+
+void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd)
+{
+	int i;
+	if (hcd->msix_entries) {
+		for (i = 0; i < hcd->msix_count; i++)
+			synchronize_irq(hcd->msix_entries[i].vector);
+	}
+
+}
+EXPORT_SYMBOL_GPL(usb_hcd_msix_sync_irqs);
+
+/*
+ * Set up MSI
+ */
+static int hcd_setup_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	ret = pci_enable_msi(pdev);
+	if (ret)
+		dev_dbg(&pdev->dev, "failed to allocate MSI entry\n");
+	return ret;
+}
+
+/*
+ * Set up MSI-X
+ */
+static int hcd_setup_msix(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int i, ret = 0;
+
+	/*
+	 * calculate number of msi-x vectors supported.
+	 * Add additional 1 vector to ensure always available interrupt.
+	 */
+	hcd->msix_count = min((int)num_online_cpus() + 1,
+				hcd->driver->get_msix_num(hcd));
+
+	hcd->msix_entries =
+		kmalloc((sizeof(struct msix_entry))*hcd->msix_count,
+				GFP_KERNEL);
+	if (!hcd->msix_entries) {
+		dev_err(&pdev->dev, "Failed to allocate MSI-X entries\n");
+		hcd->msix_count = 0;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < hcd->msix_count; i++) {
+		hcd->msix_entries[i].entry = i;
+		hcd->msix_entries[i].vector = 0;
+	}
+
+	ret = pci_enable_msix(pdev, hcd->msix_entries, hcd->msix_count);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failed to enable MSI-X\n");
+		goto free_entries;
+	}
+
+	return ret;
+
+free_entries:
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_count = 0;
+	return ret;
+}
+
+/* Device for a quirk */
+#define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
+#define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
+
+/* Check for buggy HCD devices, and driver's expectation for MSI.
+ * Now, only xhci driver want it by HCD_MSI_FIRST setting. Other driver
+ * like ehci/uhci can follow this setting, if they want.
+ */
+static int hcd_no_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	if (pdev->vendor == PCI_VENDOR_ID_FRESCO_LOGIC &&
+			pdev->device == PCI_DEVICE_ID_FRESCO_LOGIC_PDK) {
+
+		/* Fresco Logic confirms: all revisions of this chip do not
+		 * support MSI, even though some of them claim to in their PCI
+		 * capabilities.
+		 */
+		dev_dbg(&pdev->dev, "QUIRK: Fresco Logic revision %u "
+				"has broken MSI implementation\n",
+				pdev->revision);
+		return 1;
+	}
+	if (!(hcd->driver->flags & HCD_MSI_FIRST))
+		return 1;
+
+	return 0;
+}
+
+/* setup msi/msix interrupts. if fails, fallback to line irq */
+static int hcd_setup_int(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	hcd->irq = -1;
+
+	if (!hcd_no_msi(pdev, hcd)) {
+
+		ret = hcd_setup_msix(pdev, hcd);
+		if (ret)
+			/* fall back to msi*/
+			ret = hcd_setup_msi(pdev, hcd);
+
+		if (!ret)
+			/* hcd->irq is -1, we have MSI */
+			return 0;
+	}
+
+	if (!pdev->irq) {
+		dev_err(&pdev->dev, "No msi or line irq found!\n");
+		return -1;
+	}
+	/* fallback to line irq */
+	hcd->irq = pdev->irq;
+	return 0;
+}
+
+int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+					unsigned long irqflags)
+{
+	int retval = 1;
+	if (hcd->msix_entries && hcd->driver->irq) {
+		int i;
+		/* register hc_driver's msix_irq handler */
+		for (i = 0; i < hcd->msix_count; i++) {
+			retval = request_irq(hcd->msix_entries[i].vector,
+					(irq_handler_t)hcd->driver->msix_irq,
+					0, hcd->driver->description, hcd);
+			if (retval) {
+				hcd_free_msix(hcd);
+				break;
+			}
+		}
+		if (i == hcd->msix_count)
+			hcd->msix_enabled = 1;
+	} else if (hcd->irq == -1) {
+		/* register hc_driver's msi_irq handler */
+		retval = request_irq(irqnum,
+					(irq_handler_t)hcd->driver->msi_irq,
+					0, hcd->driver->description, hcd);
+		if (retval)
+			hcd_free_msi(hcd);
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_request_msi_msix_irqs);
+
+/* setup msi/msix interrupts and requestion irqs for them */
+int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd)
+{
+	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
+	int ret = -1;
+
+	if (!hcd_setup_int(pdev, hcd))
+		ret = usb_hcd_request_msi_msix_irqs(hcd,
+				pdev->irq, IRQF_SHARED);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_register_msi_msix_irqs);
+
 /* configure so an HC device and id are always provided */
 /* always called with process context; sleeping is OK */
 
@@ -187,10 +399,8 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	/* The xHCI driver supports MSI and MSI-X,
-	 * so don't fail if the BIOS doesn't provide a legacy IRQ.
-	 */
-	if (!dev->irq && (driver->flags & HCD_MASK) != HCD_USB3) {
+	/* skip irq check if hcd wants MSI firstly. */
+	if (!(driver->flags & HCD_MSI_FIRST) && !dev->irq) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));
@@ -245,6 +455,11 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	pci_set_master(dev);
 
+	/* try enable MSI, if fail, seek line irq */
+	retval = hcd_setup_int(dev, hcd);
+	if (retval != 0)
+		goto unmap_registers;
+
 	retval = usb_add_hcd(hcd, dev->irq, IRQF_SHARED);
 	if (retval != 0)
 		goto unmap_registers;
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index e128232..32ddad0 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2322,7 +2322,7 @@ int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
 
-static int usb_hcd_request_irqs(struct usb_hcd *hcd,
+static int usb_hcd_request_default_irqs(struct usb_hcd *hcd,
 		unsigned int irqnum, unsigned long irqflags)
 {
 	int retval;
@@ -2362,6 +2362,20 @@ static int usb_hcd_request_irqs(struct usb_hcd *hcd,
 	return 0;
 }
 
+int usb_hcd_request_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+		unsigned long irqflags)
+{
+	int retval = 1;
+
+#ifdef CONFIG_PCI
+	retval = usb_hcd_request_msi_msix_irqs(hcd, irqnum, irqflags);
+#endif
+	if (retval)
+		retval = usb_hcd_request_default_irqs(hcd, irqnum, irqflags);
+
+	return retval;
+}
+
 /**
  * usb_add_hcd - finish generic HCD structure initialization and register
  * @hcd: the usb_hcd structure to initialize
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ef98b38..39be795 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -64,14 +64,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 			xhci_dbg(xhci, "QUIRK: Fresco Logic xHC needs configure"
 					" endpoint cmd after reset endpoint\n");
 		}
-		/* Fresco Logic confirms: all revisions of this chip do not
-		 * support MSI, even though some of them claim to in their PCI
-		 * capabilities.
-		 */
-		xhci->quirks |= XHCI_BROKEN_MSI;
-		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
-				"has broken MSI implementation\n",
-				pdev->revision);
 	}
 
 	if (pdev->vendor == PCI_VENDOR_ID_NEC)
@@ -124,6 +116,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
 	return retval;
 }
 
+
 /*
  * We need to register our own PCI probe function (instead of the USB core's
  * function) in order to create a second roothub under xHCI.
@@ -136,6 +129,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	struct usb_hcd *hcd;
 
 	driver = (struct hc_driver *)id->driver_data;
+
 	/* Register the USB 2.0 roothub.
 	 * FIXME: USB core must know to register the USB 2.0 roothub first.
 	 * This is sort of silly, because we could just set the HCD driver flags
@@ -243,13 +237,17 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	 * generic hardware linkage
 	 */
 	.irq =			xhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+	.msi_irq =		xhci_msi_irq,
+	.msix_irq =		xhci_msi_irq,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED |
+				HCD_MSI_FIRST,
 
 	/*
 	 * basic lifecycle operations
 	 */
 	.reset =		xhci_pci_setup,
 	.start =		xhci_run,
+	.get_msix_num =		xhci_get_msix_num,
 #ifdef CONFIG_PM
 	.pci_suspend =          xhci_pci_suspend,
 	.pci_resume =           xhci_pci_resume,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c939f5f..95dc48f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -176,210 +176,24 @@ int xhci_reset(struct xhci_hcd *xhci)
 }
 
 #ifdef CONFIG_PCI
-static int xhci_free_msi(struct xhci_hcd *xhci)
-{
-	int i;
-
-	if (!xhci->msix_entries)
-		return -EINVAL;
-
-	for (i = 0; i < xhci->msix_count; i++)
-		if (xhci->msix_entries[i].vector)
-			free_irq(xhci->msix_entries[i].vector,
-					xhci_to_hcd(xhci));
-	return 0;
-}
-
-/*
- * Set up MSI
- */
-static int xhci_setup_msi(struct xhci_hcd *xhci)
-{
-	int ret;
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-
-	ret = pci_enable_msi(pdev);
-	if (ret) {
-		xhci_dbg(xhci, "failed to allocate MSI entry\n");
-		return ret;
-	}
-
-	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-	if (ret) {
-		xhci_dbg(xhci, "disable MSI interrupt\n");
-		pci_disable_msi(pdev);
-	}
-
-	return ret;
-}
-
-/*
- * Free IRQs
- * free all IRQs request
- */
-static void xhci_free_irq(struct xhci_hcd *xhci)
-{
-	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/* return if using legacy interrupt */
-	if (xhci_to_hcd(xhci)->irq >= 0)
-		return;
-
-	ret = xhci_free_msi(xhci);
-	if (!ret)
-		return;
-	if (pdev->irq >= 0)
-		free_irq(pdev->irq, xhci_to_hcd(xhci));
-
-	return;
-}
-
-/*
- * Set up MSI-X
- */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
-{
-	int i, ret = 0;
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	/*
-	 * calculate number of msi-x vectors supported.
-	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
-	 *   with max number of interrupters based on the xhci HCSPARAMS1.
-	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
-	 *   Add additional 1 vector to ensure always available interrupt.
-	 */
-	xhci->msix_count = min(num_online_cpus() + 1,
-				HCS_MAX_INTRS(xhci->hcs_params1));
-
-	xhci->msix_entries =
-		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
-				GFP_KERNEL);
-	if (!xhci->msix_entries) {
-		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		xhci->msix_entries[i].entry = i;
-		xhci->msix_entries[i].vector = 0;
-	}
-
-	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
-	if (ret) {
-		xhci_dbg(xhci, "Failed to enable MSI-X\n");
-		goto free_entries;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		ret = request_irq(xhci->msix_entries[i].vector,
-				(irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-		if (ret)
-			goto disable_msix;
-	}
-
-	hcd->msix_enabled = 1;
-	return ret;
-
-disable_msix:
-	xhci_dbg(xhci, "disable MSI-X interrupt\n");
-	xhci_free_irq(xhci);
-	pci_disable_msix(pdev);
-free_entries:
-	kfree(xhci->msix_entries);
-	xhci->msix_entries = NULL;
-	return ret;
-}
-
-/* Free any IRQs and disable MSI-X */
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	xhci_free_irq(xhci);
-
-	if (xhci->msix_entries) {
-		pci_disable_msix(pdev);
-		kfree(xhci->msix_entries);
-		xhci->msix_entries = NULL;
-	} else {
-		pci_disable_msi(pdev);
-	}
-
-	hcd->msix_enabled = 0;
-	return;
-}
 
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
-	int i;
-
-	if (xhci->msix_entries) {
-		for (i = 0; i < xhci->msix_count; i++)
-			synchronize_irq(xhci->msix_entries[i].vector);
-	}
+	usb_hcd_msix_sync_irqs(xhci_to_hcd(xhci));
 }
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
+/* called in interrupt setup during pci probe() */
+int xhci_get_msix_num(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/*
-	 * Some Fresco Logic host controllers advertise MSI, but fail to
-	 * generate interrupts.  Don't even try to enable MSI.
-	 */
-	if (xhci->quirks & XHCI_BROKEN_MSI)
-		return 0;
-
-	/* unregister the legacy interrupt */
-	if (hcd->irq)
-		free_irq(hcd->irq, hcd);
-	hcd->irq = -1;
 
-	ret = xhci_setup_msix(xhci);
-	if (ret)
-		/* fall back to msi*/
-		ret = xhci_setup_msi(xhci);
-
-	if (!ret)
-		/* hcd->irq is -1, we have MSI */
-		return 0;
-
-	if (!pdev->irq) {
-		xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
-		return -EINVAL;
-	}
-
-	/* fall back to legacy interrupt*/
-	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
-			hcd->irq_descr, hcd);
-	if (ret) {
-		xhci_err(xhci, "request interrupt %d failed\n",
-				pdev->irq);
-		return ret;
-	}
-	hcd->irq = pdev->irq;
-	return 0;
+	/* danger: xhci may be null, but it's useless in xhci_readl() now */
+	return HCS_MAX_INTRS(xhci_readl(xhci,
+			&((struct xhci_cap_regs *)hcd->regs)->hcs_params1));
 }
 
 #else
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
-{
-	return 0;
-}
-
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-}
-
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
 }
@@ -411,7 +225,6 @@ int xhci_init(struct usb_hcd *hcd)
 
 	return retval;
 }
-
 /*-------------------------------------------------------------------------*/
 
 
@@ -497,7 +310,6 @@ int xhci_run(struct usb_hcd *hcd)
 {
 	u32 temp;
 	u64 temp_64;
-	int ret;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
 	/* Start the xHCI host controller running only after the USB 2.0 roothub
@@ -510,10 +322,6 @@ int xhci_run(struct usb_hcd *hcd)
 
 	xhci_dbg(xhci, "xhci_run\n");
 
-	ret = xhci_try_enable_msi(hcd);
-	if (ret)
-		return ret;
-
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	init_timer(&xhci->event_ring_timer);
 	xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -609,7 +417,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_reset(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	/* Tell the event ring poll function not to reschedule */
@@ -651,7 +459,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_halt(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
 		    xhci_readl(xhci, &xhci->op_regs->status));
@@ -853,7 +661,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		xhci_halt(xhci);
 		xhci_reset(xhci);
 		spin_unlock_irq(&xhci->lock);
-		xhci_cleanup_msix(xhci);
+		usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 		/* Tell the event ring poll function not to reschedule */
@@ -888,7 +696,11 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		if (retval)
 			return retval;
 		xhci_dbg(xhci, "Start the primary HCD\n");
-		retval = xhci_run(hcd->primary_hcd);
+		if (dev_is_pci(hcd->self.controller))
+			retval = usb_hcd_register_msi_msix_irqs(
+						hcd->primary_hcd);
+		if (!retval)
+			retval = xhci_run(hcd->primary_hcd);
 		if (!retval) {
 			xhci_dbg(xhci, "Start the secondary HCD\n");
 			retval = xhci_run(secondary_hcd);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fb99c83..8d511dd 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1388,9 +1388,6 @@ struct xhci_hcd {
 	int		page_size;
 	/* Valid values are 12 to 20, inclusive */
 	int		page_shift;
-	/* msi-x vectors */
-	int		msix_count;
-	struct msix_entry	*msix_entries;
 	/* data structures */
 	struct xhci_device_context_array *dcbaa;
 	struct xhci_ring	*cmd_ring;
@@ -1643,9 +1640,11 @@ void xhci_free_command(struct xhci_hcd *xhci,
 /* xHCI PCI glue */
 int xhci_register_pci(void);
 void xhci_unregister_pci(void);
+int xhci_get_msix_num(struct usb_hcd *hcd);
 #else
 static inline int xhci_register_pci(void) { return 0; }
 static inline void xhci_unregister_pci(void) {}
+static inline int xhci_get_msix_num(struct usb_hcd *hcd) { return 0; }
 #endif
 
 /* xHCI host controller glue */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index b2f62f3..78a11e0 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -22,6 +22,7 @@
 #ifdef __KERNEL__
 
 #include <linux/rwsem.h>
+#include <linux/pci.h>		/* for struct msix_entry */
 
 #define MAX_TOPO_LEVEL		6
 
@@ -133,6 +134,12 @@ struct usb_hcd {
 	u64			rsrc_len;	/* memory/io resource length */
 	unsigned		power_budget;	/* in mA, 0 = no limit */
 
+#ifdef CONFIG_PCI
+	/* msi-x vectors */
+	int			msix_count;
+	struct msix_entry	*msix_entries;
+#endif
+
 	/* bandwidth_mutex should be taken before adding or removing
 	 * any new bus bandwidth constraints:
 	 *   1. Before adding a configuration for a new device.
@@ -205,11 +212,14 @@ struct hc_driver {
 
 	/* irq handler */
 	irqreturn_t	(*irq) (struct usb_hcd *hcd);
+	irqreturn_t	(*msi_irq) (struct usb_hcd *hcd);
+	irqreturn_t	(*msix_irq) (struct usb_hcd *hcd);
 
 	int	flags;
 #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
 #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
 #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
+#define	HCD_MSI_FIRST	0x0008		/* Try to get MSI first, PCI only */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
 #define	HCD_USB3	0x0040		/* USB 3.0 */
@@ -218,6 +228,7 @@ struct hc_driver {
 	/* called to init HCD and root hub */
 	int	(*reset) (struct usb_hcd *hcd);
 	int	(*start) (struct usb_hcd *hcd);
+	int	(*get_msix_num) (struct usb_hcd *hcd);
 
 	/* NOTE:  these suspend/resume calls relate to the HC as
 	 * a whole, not just the root hub; they're for PCI bus glue.
@@ -393,6 +404,12 @@ extern int usb_hcd_pci_probe(struct pci_dev *dev,
 extern void usb_hcd_pci_remove(struct pci_dev *dev);
 extern void usb_hcd_pci_shutdown(struct pci_dev *dev);
 
+extern void usb_hcd_free_msi_msix(struct usb_hcd *hcd);
+extern void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd);
+extern int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd,
+		unsigned int irqnum, unsigned long irqflags);
+extern int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd);
+
 #ifdef CONFIG_PM_SLEEP
 extern const struct dev_pm_ops usb_hcd_pci_pm_ops;
 #endif
-- 
1.6.3.3

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Clemens Ladisch]

Alex,Shi wrote:
> On Thu, 2012-02-16 at 10:36 +0800, Alex,Shi wrote:
>>>> +/* msi irq handler should be here, if driver has */
>>>> +irqreturn_t hcd_msi_irq(int irq, struct usb_hcd *hcd)
>>>> +{
>>>> +	return hcd->driver->irq(hcd);
>>>> +}
>>>
>>> This works for now, but it isn't going to work in the future.  We need
>>> the USB core to provide us with the irq number so we can map the MSI-X
>>> interrupt to the event ring that generated the interrupt, whenever we
>>> get around to adding multiple event rings.
>>
>> Do you mean to add 2 new vectors for MSI/MSIX in hc_driver?
>
> +	irqreturn_t	(*msi_irq) (struct usb_hcd *hcd);
> +	irqreturn_t	(*msix_irq) (struct usb_hcd *hcd);

The controller driver will need to know which of the multiple MSI-X
interrupts has been raised:

irqreturn_t (*msix_irq)(struct usb_hcd *hcd, unsigned int nr_or_index);


Regards,
Clemens

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

> The controller driver will need to know which of the multiple MSI-X
> interrupts has been raised:
> 
> irqreturn_t (*msix_irq)(struct usb_hcd *hcd, unsigned int nr_or_index);

Actually, hcd has 2 object for msix, msix_count and msix_entries. 

Do you mean msix_count maybe smaller than we decide in hcd_setup_msix()?
Which situation will make this? 

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Clemens Ladisch]

Alex,Shi wrote:
>> The controller driver will need to know which of the multiple MSI-X
>> interrupts has been raised:
>>
>> irqreturn_t (*msix_irq)(struct usb_hcd *hcd, unsigned int nr_or_index);
>
> Actually, hcd has 2 object for msix, msix_count and msix_entries.
>
> Do you mean msix_count maybe smaller than we decide in hcd_setup_msix()?

No.  But when msic_count > 1, we have multiple interrupts.

> Which situation will make this?

Assume that an XHCI controller has two rings, and that each one gets its
own MSI-X interrupt.  How should the driver decide which of the rings
needs to be handled?

irqreturn_t xhci_msix_irq(struct usb_hcd *hcd)
{
	struct xhci_hcd *xhci = hcd_to_xhci(hcd);

	if (...)
		handle(xhci->ring[0]);
	else
		handle(xhci->ring[1]);
}

I.e., what should go into the if()?


Regards,
Clemens

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Andiry Xu]

On 02/17/2012 06:15 PM, Clemens Ladisch wrote:
> Alex,Shi wrote:
>>> The controller driver will need to know which of the multiple MSI-X
>>> interrupts has been raised:
>>>
>>> irqreturn_t (*msix_irq)(struct usb_hcd *hcd, unsigned int nr_or_index);
>>
>> Actually, hcd has 2 object for msix, msix_count and msix_entries.
>>
>> Do you mean msix_count maybe smaller than we decide in hcd_setup_msix()?
> 
> No.  But when msic_count > 1, we have multiple interrupts.
> 
>> Which situation will make this?
> 
> Assume that an XHCI controller has two rings, and that each one gets its
> own MSI-X interrupt.  How should the driver decide which of the rings
> needs to be handled?
> 
> irqreturn_t xhci_msix_irq(struct usb_hcd *hcd)
> {
> 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> 
> 	if (...)
> 		handle(xhci->ring[0]);
> 	else
> 		handle(xhci->ring[1]);
> }
> 
> I.e., what should go into the if()?
> 
> 

Currently xHCI driver only support one ERST event ring. If we need to
support multiple event rings in the future, it's simple: in
usb_hcd_request_msi_msix_irqs, change the last parameter of
request_irq() to xhci->erst[i], and we can get the corresponding erst[i]
in xhci_msi_irq() like this:

irqreturn_t xhci_msi_irq(int irq, void *dev_id)
{
	struct xhci_erst *erst = dev_id;
	...
	/* Handle corresponding event ring pointed by erst */
}

See Matthew Wilcox's patchset below for reference:

www.spinics.net/lists/linux-usb/msg47353.html

Thanks,
Andiry
Andiry

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

> > Assume that an XHCI controller has two rings, and that each one gets its
> > own MSI-X interrupt.  How should the driver decide which of the rings
> > needs to be handled?
> > 
> > irqreturn_t xhci_msix_irq(struct usb_hcd *hcd)
> > {
> > 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> > 
> > 	if (...)
> > 		handle(xhci->ring[0]);
> > 	else
> > 		handle(xhci->ring[1]);
> > }
> > 
> > I.e., what should go into the if()?
> > 
> > 
> 
> Currently xHCI driver only support one ERST event ring. If we need to
> support multiple event rings in the future, it's simple: in
> usb_hcd_request_msi_msix_irqs, change the last parameter of
> request_irq() to xhci->erst[i], and we can get the corresponding erst[i]
> in xhci_msi_irq() like this:
> 
> irqreturn_t xhci_msi_irq(int irq, void *dev_id)
> {
> 	struct xhci_erst *erst = dev_id;
> 	...
> 	/* Handle corresponding event ring pointed by erst */
> }
> 
> See Matthew Wilcox's patchset below for reference:
> 
> www.spinics.net/lists/linux-usb/msg47353.html

Oh. Thanks Andiry and Clemens! The problem really worth to have another
patchset for it. 

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alex,Shi]

> I rewritten the patch base on your MSI bug fixing patch. and enhanced
> with your comments. would you like review it again? 
> 

Find a stupid error the patch:

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 8fab3c6..b99be41 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -325,7 +325,7 @@ int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
 					unsigned long irqflags)
 {
 	int retval = 1;
-	if (hcd->msix_entries && hcd->driver->irq) {
+	if (hcd->msix_entries && hcd->driver->msix_irq) {
 		int i;
 		/* register hc_driver's msix_irq handler */
 		for (i = 0; i < hcd->msix_count; i++) {
@@ -339,7 +339,7 @@ int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
 		}
 		if (i == hcd->msix_count)
 			hcd->msix_enabled = 1;
-	} else if (hcd->irq == -1) {
+	} else if (hcd->irq == -1 && hcd->driver->msi_irq) {
 		/* register hc_driver's msi_irq handler */
 		retval = request_irq(irqnum,
 					(irq_handler_t)hcd->driver->msi_irq,

Now update with new fixing: 

===========
>From d28873304df0e15f9d41c1dd96dac313e011639f Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@intel.com>
Date: Fri, 17 Feb 2012 11:21:33 +0800
Subject: [PATCH v2] usb: enable pci MSI/MSIX in usb core

MSI/MSIX is the favorite interrupt for PCIe device. PCIe usb HCD should
be used more and more in future, but current USB core still just wants
line IRQ, only XHCI usb driver enabled MSI/MSIX.

This patch enabled pci MSI/MSIX in usb core for HCD, and removed MSI/MSIX
setup code from XHCI since it becomes redundant now.
There 3 places need prepare to enable MSI/MSIX in usb driver.
1, set HCD_MSI_FIRST in driver->flags to enable MSI/MSIX.
2, prepare a get_msix_num() to get msix vector numb.
3, prepare msi/msix_irq handler.

XHCI is a good example for this.

Thanks for Sarah's effort on the MSI/MSIX enabling in XHCI. In fact most
of MSI/MSIX setup functions reuse from XHCI.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
 drivers/usb/core/hcd-pci.c  |  223 ++++++++++++++++++++++++++++++++++++++++++-
 drivers/usb/core/hcd.c      |   16 +++-
 drivers/usb/host/xhci-pci.c |   16 ++--
 drivers/usb/host/xhci.c     |  216 +++---------------------------------------
 drivers/usb/host/xhci.h     |    5 +-
 include/linux/usb/hcd.h     |   17 ++++
 6 files changed, 274 insertions(+), 219 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 81e2c0d..9ae588e 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -153,6 +153,218 @@ static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
 
 /*-------------------------------------------------------------------------*/
 
+static int hcd_free_msix(struct usb_hcd *hcd)
+{
+	int i;
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (!hcd->msix_entries) {
+		printk(KERN_ERR "No msix entries found!\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < hcd->msix_count; i++)
+		if (hcd->msix_entries[i].vector)
+			free_irq(hcd->msix_entries[i].vector,
+					hcd);
+
+	pci_disable_msix(pdev);
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_enabled = 0;
+
+	return 0;
+}
+
+static int hcd_free_msi(struct usb_hcd *hcd)
+{
+	struct pci_dev  *pdev = to_pci_dev(hcd->self.controller);
+
+	if (pdev->irq > 0)
+		free_irq(pdev->irq, hcd);
+
+	pci_disable_msi(pdev);
+	return 0;
+}
+
+/* Free and disable msi/msix */
+void usb_hcd_free_msi_msix(struct usb_hcd *hcd)
+{
+	if (hcd->msix_entries)
+		hcd_free_msix(hcd);
+	else
+		hcd_free_msi(hcd);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_free_msi_msix);
+
+void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd)
+{
+	int i;
+	if (hcd->msix_entries) {
+		for (i = 0; i < hcd->msix_count; i++)
+			synchronize_irq(hcd->msix_entries[i].vector);
+	}
+
+}
+EXPORT_SYMBOL_GPL(usb_hcd_msix_sync_irqs);
+
+/*
+ * Set up MSI
+ */
+static int hcd_setup_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	ret = pci_enable_msi(pdev);
+	if (ret)
+		dev_dbg(&pdev->dev, "failed to allocate MSI entry\n");
+	return ret;
+}
+
+/*
+ * Set up MSI-X
+ */
+static int hcd_setup_msix(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int i, ret = 0;
+
+	/*
+	 * calculate number of msi-x vectors supported.
+	 * Add additional 1 vector to ensure always available interrupt.
+	 */
+	hcd->msix_count = min((int)num_online_cpus() + 1,
+				hcd->driver->get_msix_num(hcd));
+
+	hcd->msix_entries =
+		kmalloc((sizeof(struct msix_entry))*hcd->msix_count,
+				GFP_KERNEL);
+	if (!hcd->msix_entries) {
+		dev_err(&pdev->dev, "Failed to allocate MSI-X entries\n");
+		hcd->msix_count = 0;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < hcd->msix_count; i++) {
+		hcd->msix_entries[i].entry = i;
+		hcd->msix_entries[i].vector = 0;
+	}
+
+	ret = pci_enable_msix(pdev, hcd->msix_entries, hcd->msix_count);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failed to enable MSI-X\n");
+		goto free_entries;
+	}
+
+	return ret;
+
+free_entries:
+	kfree(hcd->msix_entries);
+	hcd->msix_entries = NULL;
+	hcd->msix_count = 0;
+	return ret;
+}
+
+/* Device for a quirk */
+#define PCI_VENDOR_ID_FRESCO_LOGIC	0x1b73
+#define PCI_DEVICE_ID_FRESCO_LOGIC_PDK	0x1000
+
+/* Check for buggy HCD devices, and driver's expectation for MSI.
+ * Now, only xhci driver want it by HCD_MSI_FIRST setting. Other driver
+ * like ehci/uhci can follow this setting, if they want.
+ */
+static int hcd_no_msi(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	if (pdev->vendor == PCI_VENDOR_ID_FRESCO_LOGIC &&
+			pdev->device == PCI_DEVICE_ID_FRESCO_LOGIC_PDK) {
+
+		/* Fresco Logic confirms: all revisions of this chip do not
+		 * support MSI, even though some of them claim to in their PCI
+		 * capabilities.
+		 */
+		dev_dbg(&pdev->dev, "QUIRK: Fresco Logic revision %u "
+				"has broken MSI implementation\n",
+				pdev->revision);
+		return 1;
+	}
+	if (!(hcd->driver->flags & HCD_MSI_FIRST))
+		return 1;
+
+	return 0;
+}
+
+/* setup msi/msix interrupts. if fails, fallback to line irq */
+static int hcd_setup_int(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	int ret;
+
+	hcd->irq = -1;
+
+	if (!hcd_no_msi(pdev, hcd)) {
+
+		ret = hcd_setup_msix(pdev, hcd);
+		if (ret)
+			/* fall back to msi*/
+			ret = hcd_setup_msi(pdev, hcd);
+
+		if (!ret)
+			/* hcd->irq is -1, we have MSI */
+			return 0;
+	}
+
+	if (!pdev->irq) {
+		dev_err(&pdev->dev, "No msi or line irq found!\n");
+		return -1;
+	}
+	/* fallback to line irq */
+	hcd->irq = pdev->irq;
+	return 0;
+}
+
+int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+					unsigned long irqflags)
+{
+	int retval = 1;
+	if (hcd->msix_entries && hcd->driver->msix_irq) {
+		int i;
+		/* register hc_driver's msix_irq handler */
+		for (i = 0; i < hcd->msix_count; i++) {
+			retval = request_irq(hcd->msix_entries[i].vector,
+					(irq_handler_t)hcd->driver->msix_irq,
+					0, hcd->driver->description, hcd);
+			if (retval) {
+				hcd_free_msix(hcd);
+				break;
+			}
+		}
+		if (i == hcd->msix_count)
+			hcd->msix_enabled = 1;
+	} else if (hcd->irq == -1 && hcd->driver->msi_irq) {
+		/* register hc_driver's msi_irq handler */
+		retval = request_irq(irqnum,
+					(irq_handler_t)hcd->driver->msi_irq,
+					0, hcd->driver->description, hcd);
+		if (retval)
+			hcd_free_msi(hcd);
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_request_msi_msix_irqs);
+
+/* setup msi/msix interrupts and request irqs for them */
+int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd)
+{
+	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
+	int ret = -1;
+
+	if (!hcd_setup_int(pdev, hcd))
+		ret = usb_hcd_request_msi_msix_irqs(hcd,
+				pdev->irq, IRQF_SHARED);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_register_msi_msix_irqs);
+
 /* configure so an HC device and id are always provided */
 /* always called with process context; sleeping is OK */
 
@@ -187,10 +399,8 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	/* The xHCI driver supports MSI and MSI-X,
-	 * so don't fail if the BIOS doesn't provide a legacy IRQ.
-	 */
-	if (!dev->irq && (driver->flags & HCD_MASK) != HCD_USB3) {
+	/* skip irq check if hcd wants MSI firstly. */
+	if (!(driver->flags & HCD_MSI_FIRST) && !dev->irq) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));
@@ -245,6 +455,11 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	pci_set_master(dev);
 
+	/* try enable MSI, if fail, seek line irq */
+	retval = hcd_setup_int(dev, hcd);
+	if (retval != 0)
+		goto unmap_registers;
+
 	retval = usb_add_hcd(hcd, dev->irq, IRQF_SHARED);
 	if (retval != 0)
 		goto unmap_registers;
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index e128232..32ddad0 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2322,7 +2322,7 @@ int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
 }
 EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
 
-static int usb_hcd_request_irqs(struct usb_hcd *hcd,
+static int usb_hcd_request_default_irqs(struct usb_hcd *hcd,
 		unsigned int irqnum, unsigned long irqflags)
 {
 	int retval;
@@ -2362,6 +2362,20 @@ static int usb_hcd_request_irqs(struct usb_hcd *hcd,
 	return 0;
 }
 
+int usb_hcd_request_irqs(struct usb_hcd *hcd, unsigned int irqnum,
+		unsigned long irqflags)
+{
+	int retval = 1;
+
+#ifdef CONFIG_PCI
+	retval = usb_hcd_request_msi_msix_irqs(hcd, irqnum, irqflags);
+#endif
+	if (retval)
+		retval = usb_hcd_request_default_irqs(hcd, irqnum, irqflags);
+
+	return retval;
+}
+
 /**
  * usb_add_hcd - finish generic HCD structure initialization and register
  * @hcd: the usb_hcd structure to initialize
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ef98b38..39be795 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -64,14 +64,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 			xhci_dbg(xhci, "QUIRK: Fresco Logic xHC needs configure"
 					" endpoint cmd after reset endpoint\n");
 		}
-		/* Fresco Logic confirms: all revisions of this chip do not
-		 * support MSI, even though some of them claim to in their PCI
-		 * capabilities.
-		 */
-		xhci->quirks |= XHCI_BROKEN_MSI;
-		xhci_dbg(xhci, "QUIRK: Fresco Logic revision %u "
-				"has broken MSI implementation\n",
-				pdev->revision);
 	}
 
 	if (pdev->vendor == PCI_VENDOR_ID_NEC)
@@ -124,6 +116,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
 	return retval;
 }
 
+
 /*
  * We need to register our own PCI probe function (instead of the USB core's
  * function) in order to create a second roothub under xHCI.
@@ -136,6 +129,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	struct usb_hcd *hcd;
 
 	driver = (struct hc_driver *)id->driver_data;
+
 	/* Register the USB 2.0 roothub.
 	 * FIXME: USB core must know to register the USB 2.0 roothub first.
 	 * This is sort of silly, because we could just set the HCD driver flags
@@ -243,13 +237,17 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	 * generic hardware linkage
 	 */
 	.irq =			xhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+	.msi_irq =		xhci_msi_irq,
+	.msix_irq =		xhci_msi_irq,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED |
+				HCD_MSI_FIRST,
 
 	/*
 	 * basic lifecycle operations
 	 */
 	.reset =		xhci_pci_setup,
 	.start =		xhci_run,
+	.get_msix_num =		xhci_get_msix_num,
 #ifdef CONFIG_PM
 	.pci_suspend =          xhci_pci_suspend,
 	.pci_resume =           xhci_pci_resume,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c939f5f..95dc48f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -176,210 +176,24 @@ int xhci_reset(struct xhci_hcd *xhci)
 }
 
 #ifdef CONFIG_PCI
-static int xhci_free_msi(struct xhci_hcd *xhci)
-{
-	int i;
-
-	if (!xhci->msix_entries)
-		return -EINVAL;
-
-	for (i = 0; i < xhci->msix_count; i++)
-		if (xhci->msix_entries[i].vector)
-			free_irq(xhci->msix_entries[i].vector,
-					xhci_to_hcd(xhci));
-	return 0;
-}
-
-/*
- * Set up MSI
- */
-static int xhci_setup_msi(struct xhci_hcd *xhci)
-{
-	int ret;
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-
-	ret = pci_enable_msi(pdev);
-	if (ret) {
-		xhci_dbg(xhci, "failed to allocate MSI entry\n");
-		return ret;
-	}
-
-	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-	if (ret) {
-		xhci_dbg(xhci, "disable MSI interrupt\n");
-		pci_disable_msi(pdev);
-	}
-
-	return ret;
-}
-
-/*
- * Free IRQs
- * free all IRQs request
- */
-static void xhci_free_irq(struct xhci_hcd *xhci)
-{
-	struct pci_dev *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/* return if using legacy interrupt */
-	if (xhci_to_hcd(xhci)->irq >= 0)
-		return;
-
-	ret = xhci_free_msi(xhci);
-	if (!ret)
-		return;
-	if (pdev->irq >= 0)
-		free_irq(pdev->irq, xhci_to_hcd(xhci));
-
-	return;
-}
-
-/*
- * Set up MSI-X
- */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
-{
-	int i, ret = 0;
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	/*
-	 * calculate number of msi-x vectors supported.
-	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
-	 *   with max number of interrupters based on the xhci HCSPARAMS1.
-	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
-	 *   Add additional 1 vector to ensure always available interrupt.
-	 */
-	xhci->msix_count = min(num_online_cpus() + 1,
-				HCS_MAX_INTRS(xhci->hcs_params1));
-
-	xhci->msix_entries =
-		kmalloc((sizeof(struct msix_entry))*xhci->msix_count,
-				GFP_KERNEL);
-	if (!xhci->msix_entries) {
-		xhci_err(xhci, "Failed to allocate MSI-X entries\n");
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		xhci->msix_entries[i].entry = i;
-		xhci->msix_entries[i].vector = 0;
-	}
-
-	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
-	if (ret) {
-		xhci_dbg(xhci, "Failed to enable MSI-X\n");
-		goto free_entries;
-	}
-
-	for (i = 0; i < xhci->msix_count; i++) {
-		ret = request_irq(xhci->msix_entries[i].vector,
-				(irq_handler_t)xhci_msi_irq,
-				0, "xhci_hcd", xhci_to_hcd(xhci));
-		if (ret)
-			goto disable_msix;
-	}
-
-	hcd->msix_enabled = 1;
-	return ret;
-
-disable_msix:
-	xhci_dbg(xhci, "disable MSI-X interrupt\n");
-	xhci_free_irq(xhci);
-	pci_disable_msix(pdev);
-free_entries:
-	kfree(xhci->msix_entries);
-	xhci->msix_entries = NULL;
-	return ret;
-}
-
-/* Free any IRQs and disable MSI-X */
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-
-	xhci_free_irq(xhci);
-
-	if (xhci->msix_entries) {
-		pci_disable_msix(pdev);
-		kfree(xhci->msix_entries);
-		xhci->msix_entries = NULL;
-	} else {
-		pci_disable_msi(pdev);
-	}
-
-	hcd->msix_enabled = 0;
-	return;
-}
 
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
-	int i;
-
-	if (xhci->msix_entries) {
-		for (i = 0; i < xhci->msix_count; i++)
-			synchronize_irq(xhci->msix_entries[i].vector);
-	}
+	usb_hcd_msix_sync_irqs(xhci_to_hcd(xhci));
 }
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
+/* called in interrupt setup during pci probe() */
+int xhci_get_msix_num(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	int ret;
-
-	/*
-	 * Some Fresco Logic host controllers advertise MSI, but fail to
-	 * generate interrupts.  Don't even try to enable MSI.
-	 */
-	if (xhci->quirks & XHCI_BROKEN_MSI)
-		return 0;
-
-	/* unregister the legacy interrupt */
-	if (hcd->irq)
-		free_irq(hcd->irq, hcd);
-	hcd->irq = -1;
 
-	ret = xhci_setup_msix(xhci);
-	if (ret)
-		/* fall back to msi*/
-		ret = xhci_setup_msi(xhci);
-
-	if (!ret)
-		/* hcd->irq is -1, we have MSI */
-		return 0;
-
-	if (!pdev->irq) {
-		xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
-		return -EINVAL;
-	}
-
-	/* fall back to legacy interrupt*/
-	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
-			hcd->irq_descr, hcd);
-	if (ret) {
-		xhci_err(xhci, "request interrupt %d failed\n",
-				pdev->irq);
-		return ret;
-	}
-	hcd->irq = pdev->irq;
-	return 0;
+	/* danger: xhci may be null, but it's useless in xhci_readl() now */
+	return HCS_MAX_INTRS(xhci_readl(xhci,
+			&((struct xhci_cap_regs *)hcd->regs)->hcs_params1));
 }
 
 #else
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
-{
-	return 0;
-}
-
-static void xhci_cleanup_msix(struct xhci_hcd *xhci)
-{
-}
-
 static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 {
 }
@@ -411,7 +225,6 @@ int xhci_init(struct usb_hcd *hcd)
 
 	return retval;
 }
-
 /*-------------------------------------------------------------------------*/
 
 
@@ -497,7 +310,6 @@ int xhci_run(struct usb_hcd *hcd)
 {
 	u32 temp;
 	u64 temp_64;
-	int ret;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
 	/* Start the xHCI host controller running only after the USB 2.0 roothub
@@ -510,10 +322,6 @@ int xhci_run(struct usb_hcd *hcd)
 
 	xhci_dbg(xhci, "xhci_run\n");
 
-	ret = xhci_try_enable_msi(hcd);
-	if (ret)
-		return ret;
-
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	init_timer(&xhci->event_ring_timer);
 	xhci->event_ring_timer.data = (unsigned long) xhci;
@@ -609,7 +417,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_reset(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 	/* Tell the event ring poll function not to reschedule */
@@ -651,7 +459,7 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_halt(xhci);
 	spin_unlock_irq(&xhci->lock);
 
-	xhci_cleanup_msix(xhci);
+	usb_hcd_free_msi_msix(hcd);
 
 	xhci_dbg(xhci, "xhci_shutdown completed - status = %x\n",
 		    xhci_readl(xhci, &xhci->op_regs->status));
@@ -853,7 +661,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		xhci_halt(xhci);
 		xhci_reset(xhci);
 		spin_unlock_irq(&xhci->lock);
-		xhci_cleanup_msix(xhci);
+		usb_hcd_free_msi_msix(hcd);
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
 		/* Tell the event ring poll function not to reschedule */
@@ -888,7 +696,11 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		if (retval)
 			return retval;
 		xhci_dbg(xhci, "Start the primary HCD\n");
-		retval = xhci_run(hcd->primary_hcd);
+		if (dev_is_pci(hcd->self.controller))
+			retval = usb_hcd_register_msi_msix_irqs(
+						hcd->primary_hcd);
+		if (!retval)
+			retval = xhci_run(hcd->primary_hcd);
 		if (!retval) {
 			xhci_dbg(xhci, "Start the secondary HCD\n");
 			retval = xhci_run(secondary_hcd);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fb99c83..8d511dd 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1388,9 +1388,6 @@ struct xhci_hcd {
 	int		page_size;
 	/* Valid values are 12 to 20, inclusive */
 	int		page_shift;
-	/* msi-x vectors */
-	int		msix_count;
-	struct msix_entry	*msix_entries;
 	/* data structures */
 	struct xhci_device_context_array *dcbaa;
 	struct xhci_ring	*cmd_ring;
@@ -1643,9 +1640,11 @@ void xhci_free_command(struct xhci_hcd *xhci,
 /* xHCI PCI glue */
 int xhci_register_pci(void);
 void xhci_unregister_pci(void);
+int xhci_get_msix_num(struct usb_hcd *hcd);
 #else
 static inline int xhci_register_pci(void) { return 0; }
 static inline void xhci_unregister_pci(void) {}
+static inline int xhci_get_msix_num(struct usb_hcd *hcd) { return 0; }
 #endif
 
 /* xHCI host controller glue */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index b2f62f3..78a11e0 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -22,6 +22,7 @@
 #ifdef __KERNEL__
 
 #include <linux/rwsem.h>
+#include <linux/pci.h>		/* for struct msix_entry */
 
 #define MAX_TOPO_LEVEL		6
 
@@ -133,6 +134,12 @@ struct usb_hcd {
 	u64			rsrc_len;	/* memory/io resource length */
 	unsigned		power_budget;	/* in mA, 0 = no limit */
 
+#ifdef CONFIG_PCI
+	/* msi-x vectors */
+	int			msix_count;
+	struct msix_entry	*msix_entries;
+#endif
+
 	/* bandwidth_mutex should be taken before adding or removing
 	 * any new bus bandwidth constraints:
 	 *   1. Before adding a configuration for a new device.
@@ -205,11 +212,14 @@ struct hc_driver {
 
 	/* irq handler */
 	irqreturn_t	(*irq) (struct usb_hcd *hcd);
+	irqreturn_t	(*msi_irq) (struct usb_hcd *hcd);
+	irqreturn_t	(*msix_irq) (struct usb_hcd *hcd);
 
 	int	flags;
 #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
 #define	HCD_LOCAL_MEM	0x0002		/* HC needs local memory */
 #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
+#define	HCD_MSI_FIRST	0x0008		/* Try to get MSI first, PCI only */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
 #define	HCD_USB3	0x0040		/* USB 3.0 */
@@ -218,6 +228,7 @@ struct hc_driver {
 	/* called to init HCD and root hub */
 	int	(*reset) (struct usb_hcd *hcd);
 	int	(*start) (struct usb_hcd *hcd);
+	int	(*get_msix_num) (struct usb_hcd *hcd);
 
 	/* NOTE:  these suspend/resume calls relate to the HC as
 	 * a whole, not just the root hub; they're for PCI bus glue.
@@ -393,6 +404,12 @@ extern int usb_hcd_pci_probe(struct pci_dev *dev,
 extern void usb_hcd_pci_remove(struct pci_dev *dev);
 extern void usb_hcd_pci_shutdown(struct pci_dev *dev);
 
+extern void usb_hcd_free_msi_msix(struct usb_hcd *hcd);
+extern void usb_hcd_msix_sync_irqs(struct usb_hcd *hcd);
+extern int usb_hcd_request_msi_msix_irqs(struct usb_hcd *hcd,
+		unsigned int irqnum, unsigned long irqflags);
+extern int usb_hcd_register_msi_msix_irqs(struct usb_hcd *hcd);
+
 #ifdef CONFIG_PM_SLEEP
 extern const struct dev_pm_ops usb_hcd_pci_pm_ops;
 #endif
-- 
1.6.3.3

Re: [PATCH] usb: enable pci MSI/MSIX in usb core

[Alan Stern]

On Tue, 7 Feb 2012, Sarah Sharp wrote:

> Alan, is the hc_driver structure (xhci_pci_hc_driver) shared across all
> xHCI PCI hosts in the system?

Maybe this isn't relevant to the discussion any more...  but yes, it 
is.

Alan Stern