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authorAlex Williamson <alex.williamson@redhat.com>2013-06-28 02:40:00 +0400
committerBjorn Helgaas <bhelgaas@google.com>2013-07-25 22:27:03 +0400
commit15b100dfd1c9f7558d2fba4e3d13591dab50667f (patch)
treef6fd4d2c6f37e48649cb606014c758332537d392 /drivers/pci/quirks.c
parent83db7e0bdb70a9bb93cd000fefc3fbac3394f516 (diff)
downloadlinux-15b100dfd1c9f7558d2fba4e3d13591dab50667f.tar.xz
PCI: Claim ACS support for AMD southbridge devices
AMD confirmed that peer-to-peer between these devices is not possible. We can therefore claim that they support a subset of ACS. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Donald Dutile <ddutile@redhat.com>
Diffstat (limited to 'drivers/pci/quirks.c')
-rw-r--r--drivers/pci/quirks.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e85d23044ae0..2e2ea2208f2e 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3295,11 +3295,61 @@ struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
return pci_dev_get(dev);
}
+/*
+ * AMD has indicated that the devices below do not support peer-to-peer
+ * in any system where they are found in the southbridge with an AMD
+ * IOMMU in the system. Multifunction devices that do not support
+ * peer-to-peer between functions can claim to support a subset of ACS.
+ * Such devices effectively enable request redirect (RR) and completion
+ * redirect (CR) since all transactions are redirected to the upstream
+ * root complex.
+ *
+ * http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/94086
+ * http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/94102
+ * http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/99402
+ *
+ * 1002:4385 SBx00 SMBus Controller
+ * 1002:439c SB7x0/SB8x0/SB9x0 IDE Controller
+ * 1002:4383 SBx00 Azalia (Intel HDA)
+ * 1002:439d SB7x0/SB8x0/SB9x0 LPC host controller
+ * 1002:4384 SBx00 PCI to PCI Bridge
+ * 1002:4399 SB7x0/SB8x0/SB9x0 USB OHCI2 Controller
+ */
+static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
+{
+#ifdef CONFIG_ACPI
+ struct acpi_table_header *header = NULL;
+ acpi_status status;
+
+ /* Targeting multifunction devices on the SB (appears on root bus) */
+ if (!dev->multifunction || !pci_is_root_bus(dev->bus))
+ return -ENODEV;
+
+ /* The IVRS table describes the AMD IOMMU */
+ status = acpi_get_table("IVRS", 0, &header);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ /* Filter out flags not applicable to multifunction */
+ acs_flags &= (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC | PCI_ACS_DT);
+
+ return acs_flags & ~(PCI_ACS_RR | PCI_ACS_CR) ? 0 : 1;
+#else
+ return -ENODEV;
+#endif
+}
+
static const struct pci_dev_acs_enabled {
u16 vendor;
u16 device;
int (*acs_enabled)(struct pci_dev *dev, u16 acs_flags);
} pci_dev_acs_enabled[] = {
+ { PCI_VENDOR_ID_ATI, 0x4385, pci_quirk_amd_sb_acs },
+ { PCI_VENDOR_ID_ATI, 0x439c, pci_quirk_amd_sb_acs },
+ { PCI_VENDOR_ID_ATI, 0x4383, pci_quirk_amd_sb_acs },
+ { PCI_VENDOR_ID_ATI, 0x439d, pci_quirk_amd_sb_acs },
+ { PCI_VENDOR_ID_ATI, 0x4384, pci_quirk_amd_sb_acs },
+ { PCI_VENDOR_ID_ATI, 0x4399, pci_quirk_amd_sb_acs },
{ 0 }
};