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.

The following patch postpones the configuration of the IOV capability of
the device to a later point, when the IOV capability is explicitly
enabled by the device driver.

The patch is tested on x86 and power platform.

Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 6a4d70386a3da9f54e3dc97ddf3368001948379a..0321fa3b42268841d9bc9909354a71f8a385dcc5 100644 (file)
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -347,6 +347,8 @@ 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);
+
        iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
        pci_cfg_access_lock(dev);
        pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
@@ -452,7 +454,6 @@ static int sriov_init(struct pci_dev *dev, int pos)
 
 found:
        pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
-       pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, total);
        pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
        pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
        if (!offset || (total > 1 && !stride))
@@ -465,7 +466,6 @@ 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++) {