[BUGFIX][PATCH] pci: set pci sriov page size before reading SRIOV BAR

From: Vaidyanathan Srinivasan
Date: Thu Feb 02 2012 - 12:41:37 EST

Hi Jesse,

The following patch fixes a regression introduced when an SRIOV card
is used as a PF in a 64k base page size configuration.

Reference: https://lkml.org/lkml/2012/2/1/165

Please queue this bugfix patch for the current release cycle.


pci: set pci sriov page size before reading SRIOV BAR

For an SRIOV device, PCI_SRIOV_SYS_PGSIZE should be set before
the PCI_SRIOV_BAR are queried. The sys pagesize defaults to 4k,
so this change is required on powerpc box with 64k base page size.

This is a regression caused due to moving SRIOV init to sriov_enable().

| commit afd24ece5c76af87f6fc477f2747b83a764f161c
| Author: Ram Pai <linuxram@xxxxxxxxxx>

| PCI: delay configuration of SRIOV capability
| The SRIOV capability, namely page size and total_vfs of a device are
| configured during enumeration phase of the device. This can potentially
| interfere with the PCI operations of the platform, if the IOV capability
| of the device is not enabled.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx>
Acked-by: Ram Pai <linuxram@xxxxxxxxxx>

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 0321fa3..0dab5ec 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -347,8 +347,6 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
return rc;

- pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
@@ -466,6 +464,7 @@ found:
return -EIO;

pgsz &= ~(pgsz - 1);
+ pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);

nres = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {

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