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PCI/IOV: Use VF0 cached config registers for other VFs

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Cache some config data from VF0 and use it for all other VFs instead of
reading it from the config space of each VF.  We assume these items are the
same across all associated VFs:

   Revision ID
   Class Code
   Subsystem Vendor ID
   Subsystem ID

This is an optimization when enabling SR-IOV on a device with many VFs.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
[bhelgaas: changelog, simplify comments, remove unused "device", test
CONFIG_PCI_IOV instead of CONFIG_PCI_ATS, rename functions]
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
This commit is contained in:
KarimAllah Ahmed
2018-03-19 21:06:00 +01:00
committed by Bjorn Helgaas
parent bf4447fd1c
commit cf0921bea6
3 changed files with 81 additions and 12 deletions
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47
drivers/pci/probe.c
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@@ -1400,6 +1400,43 @@ int pci_cfg_space_size(struct pci_dev *dev)
return PCI_CFG_SPACE_SIZE;
}
static u32 pci_class(struct pci_dev *dev)
{
u32 class;
#ifdef CONFIG_PCI_IOV
if (dev->is_virtfn)
return dev->physfn->sriov->class;
#endif
pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);
return class;
}
static void pci_subsystem_ids(struct pci_dev *dev, u16 *vendor, u16 *device)
{
#ifdef CONFIG_PCI_IOV
if (dev->is_virtfn) {
*vendor = dev->physfn->sriov->subsystem_vendor;
*device = dev->physfn->sriov->subsystem_device;
return;
}
#endif
pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, vendor);
pci_read_config_word(dev, PCI_SUBSYSTEM_ID, device);
}
static u8 pci_hdr_type(struct pci_dev *dev)
{
u8 hdr_type;
#ifdef CONFIG_PCI_IOV
if (dev->is_virtfn)
return dev->physfn->sriov->hdr_type;
#endif
pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type);
return hdr_type;
}
#define LEGACY_IO_RESOURCE (IORESOURCE_IO | IORESOURCE_PCI_FIXED)
static void pci_msi_setup_pci_dev(struct pci_dev *dev)
@@ -1465,8 +1502,7 @@ int pci_setup_device(struct pci_dev *dev)
struct pci_bus_region region;
struct resource *res;
if (pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type))
return -EIO;
hdr_type = pci_hdr_type(dev);
dev->sysdata = dev->bus->sysdata;
dev->dev.parent = dev->bus->bridge;
@@ -1488,7 +1524,8 @@ int pci_setup_device(struct pci_dev *dev)
dev->bus->number, PCI_SLOT(dev->devfn),
PCI_FUNC(dev->devfn));
pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);
class = pci_class(dev);
dev->revision = class & 0xff;
dev->class = class >> 8; /* upper 3 bytes */
@@ -1528,8 +1565,8 @@ int pci_setup_device(struct pci_dev *dev)
goto bad;
pci_read_irq(dev);
pci_read_bases(dev, 6, PCI_ROM_ADDRESS);
pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device);
pci_subsystem_ids(dev, &dev->subsystem_vendor, &dev->subsystem_device);
/*
* Do the ugly legacy mode stuff here rather than broken chip