Re: [PATCH 01/22] Added some infrastructure to allow assigning PCI device IRQs at device enable time and removed pci_fixup_irqs as the other change obsolites it.

[Wei Yang <weiyang@linux.vnet.ibm.com>]

On Thu, Aug 07, 2014 at 12:35:41PM +0100, Matthew Minter wrote:
>Just to confirm, are you saying that:
>
>>+
>>+      pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
>>+      pdev_assign_irq(dev, hbrg->swizzle_irq, hbrg->map_irq);
>>+
>
>Should become:
>
>>+
>>+     pdev_assign_irq(dev, hbrg->swizzle_irq, hbrg->map_irq);
>>+     pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
>>+
>
>So that we read the config byte after running the assignment and fixup?
>
>I had not thought about the case where the fixup changes the
>PCI_INTERRUPT_PIN value.
>It looks to me like you are correct there and this should indeed be fixed.
>I can certainly swap those around for the next patch revision if that
>is what you are suggesting?
>

Yes, pci_read_config_byte() should be called after pdev_assign_irq().

>I will give that a quick test but it sounds like you are correct.

I am willing to know the result, especially in the original one, what pin
value you retrieved from pci_dev.

>
>Many thanks,
>Matthew
>
>On 7 August 2014 04:43, Wei Yang <weiyang@linux.vnet.ibm.com> wrote:
>> On Tue, Aug 05, 2014 at 05:11:02PM +0100, matthew_minter@xyratex.com wrote:
>>>From: matthew_minter <matthew_minter@xyratex.com>
>>>
>>>---
>>> drivers/pci/Makefile      | 15 ++-------------
>>> drivers/pci/host-bridge.c |  2 +-
>>> drivers/pci/pci.c         |  6 +++++-
>>> drivers/pci/pci.h         |  1 +
>>> drivers/pci/probe.c       | 12 ------------
>>> drivers/pci/setup-irq.c   | 25 +++++++++----------------
>>> include/linux/pci.h       |  8 ++++----
>>> 7 files changed, 22 insertions(+), 47 deletions(-)
>>>
>>>diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
>>>index e04fe2d..38c4cb0 100644
>>>--- a/drivers/pci/Makefile
>>>+++ b/drivers/pci/Makefile
>>>@@ -4,7 +4,8 @@
>>>
>>> obj-y         += access.o bus.o probe.o host-bridge.o remove.o pci.o \
>>>                       pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \
>>>-                      irq.o vpd.o setup-bus.o vc.o
>>>+                      irq.o vpd.o setup-bus.o vc.o setup-irq.o
>>>+
>>> obj-$(CONFIG_PROC_FS) += proc.o
>>> obj-$(CONFIG_SYSFS) += slot.o
>>>
>>>@@ -31,18 +32,6 @@ obj-$(CONFIG_PCI_ATS) += ats.o
>>> obj-$(CONFIG_PCI_IOV) += iov.o
>>>
>>> #
>>>-# Some architectures use the generic PCI setup functions
>>>-#
>>>-obj-$(CONFIG_ALPHA) += setup-irq.o
>>>-obj-$(CONFIG_ARM) += setup-irq.o
>>>-obj-$(CONFIG_UNICORE32) += setup-irq.o
>>>-obj-$(CONFIG_SUPERH) += setup-irq.o
>>>-obj-$(CONFIG_MIPS) += setup-irq.o
>>>-obj-$(CONFIG_TILE) += setup-irq.o
>>>-obj-$(CONFIG_SPARC_LEON) += setup-irq.o
>>>-obj-$(CONFIG_M68K) += setup-irq.o
>>>-
>>>-#
>>> # ACPI Related PCI FW Functions
>>> # ACPI _DSM provided firmware instance and string name
>>> #
>>>diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
>>>index 0e5f3c9..8ed186f 100644
>>>--- a/drivers/pci/host-bridge.c
>>>+++ b/drivers/pci/host-bridge.c
>>>@@ -16,7 +16,7 @@ static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
>>>       return bus;
>>> }
>>>
>>>-static struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
>>>+struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
>>> {
>>>       struct pci_bus *root_bus = find_pci_root_bus(bus);
>>>
>>>diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>>>index 63a54a3..d51d076 100644
>>>--- a/drivers/pci/pci.c
>>>+++ b/drivers/pci/pci.c
>>>@@ -1197,10 +1197,15 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars)
>>>       int err;
>>>       u16 cmd;
>>>       u8 pin;
>>>+      struct pci_host_bridge *hbrg = find_pci_host_bridge(dev->bus);
>>>
>>>       err = pci_set_power_state(dev, PCI_D0);
>>>       if (err < 0 && err != -EIO)
>>>               return err;
>>>+
>>>+      pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
>>>+      pdev_assign_irq(dev, hbrg->swizzle_irq, hbrg->map_irq);
>>>+
>>>       err = pcibios_enable_device(dev, bars);
>>>       if (err < 0)
>>>               return err;
>>>@@ -1209,7 +1214,6 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars)
>>>       if (dev->msi_enabled || dev->msix_enabled)
>>>               return 0;
>>>
>>>-      pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
>>
>> Not sure why you move this up.
>>
>> Before your change, the call flow would be like this:
>>
>> | scan_bus
>> |   + pci_fixup_irqs
>> |      +    pci_dev->irq and PCI_INTERRUPT_PIN assigned with correct number
>> |
>> | pci_enable_device, called from driver
>> |   + do_pci_enable_device, read the pin from pci_dev
>>
>> As my understanding, this ensures the pin read from hardware is fixuped. While
>> after your change, the pci_fixup_irqs is removed and the pin will be assigned
>> in pdev_assign_irq() after you fix it properly.
>>
>> Do I missed something?
>>
>>>       if (pin) {
>>>               pci_read_config_word(dev, PCI_COMMAND, &cmd);
>>>               if (cmd & PCI_COMMAND_INTX_DISABLE)
>>
>> --
>> Richard Yang
>> Help you, Help me
>>
>
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>
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-- 
Richard Yang
Help you, Help me