diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pci/pci.c | 93 | ||||
| -rw-r--r-- | drivers/pci/quirks.c | 50 |
2 files changed, 127 insertions, 16 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e37fea6e178d..a599a6bbdf37 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2359,6 +2359,27 @@ void pci_enable_acs(struct pci_dev *dev) pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); } +static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags) +{ + int pos; + u16 cap, ctrl; + + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS); + if (!pos) + return false; + + /* + * Except for egress control, capabilities are either required + * or only required if controllable. Features missing from the + * capability field can therefore be assumed as hard-wired enabled. + */ + pci_read_config_word(pdev, pos + PCI_ACS_CAP, &cap); + acs_flags &= (cap | PCI_ACS_EC); + + pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); + return (ctrl & acs_flags) == acs_flags; +} + /** * pci_acs_enabled - test ACS against required flags for a given device * @pdev: device to test @@ -2366,36 +2387,76 @@ void pci_enable_acs(struct pci_dev *dev) * * Return true if the device supports the provided flags. Automatically * filters out flags that are not implemented on multifunction devices. + * + * Note that this interface checks the effective ACS capabilities of the + * device rather than the actual capabilities. For instance, most single + * function endpoints are not required to support ACS because they have no + * opportunity for peer-to-peer access. We therefore return 'true' + * regardless of whether the device exposes an ACS capability. This makes + * it much easier for callers of this function to ignore the actual type + * or topology of the device when testing ACS support. */ bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags) { - int pos, ret; - u16 ctrl; + int ret; ret = pci_dev_specific_acs_enabled(pdev, acs_flags); if (ret >= 0) return ret > 0; + /* + * Conventional PCI and PCI-X devices never support ACS, either + * effectively or actually. The shared bus topology implies that + * any device on the bus can receive or snoop DMA. + */ if (!pci_is_pcie(pdev)) return false; - /* Filter out flags not applicable to multifunction */ - if (pdev->multifunction) - acs_flags &= (PCI_ACS_RR | PCI_ACS_CR | - PCI_ACS_EC | PCI_ACS_DT); - - if (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM || - pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT || - pdev->multifunction) { - pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS); - if (!pos) - return false; + switch (pci_pcie_type(pdev)) { + /* + * PCI/X-to-PCIe bridges are not specifically mentioned by the spec, + * but since their primary inteface is PCI/X, we conservatively + * handle them as we would a non-PCIe device. + */ + case PCI_EXP_TYPE_PCIE_BRIDGE: + /* + * PCIe 3.0, 6.12.1 excludes ACS on these devices. "ACS is never + * applicable... must never implement an ACS Extended Capability...". + * This seems arbitrary, but we take a conservative interpretation + * of this statement. + */ + case PCI_EXP_TYPE_PCI_BRIDGE: + case PCI_EXP_TYPE_RC_EC: + return false; + /* + * PCIe 3.0, 6.12.1.1 specifies that downstream and root ports should + * implement ACS in order to indicate their peer-to-peer capabilities, + * regardless of whether they are single- or multi-function devices. + */ + case PCI_EXP_TYPE_DOWNSTREAM: + case PCI_EXP_TYPE_ROOT_PORT: + return pci_acs_flags_enabled(pdev, acs_flags); + /* + * PCIe 3.0, 6.12.1.2 specifies ACS capabilities that should be + * implemented by the remaining PCIe types to indicate peer-to-peer + * capabilities, but only when they are part of a multifunciton + * device. The footnote for section 6.12 indicates the specific + * PCIe types included here. + */ + case PCI_EXP_TYPE_ENDPOINT: + case PCI_EXP_TYPE_UPSTREAM: + case PCI_EXP_TYPE_LEG_END: + case PCI_EXP_TYPE_RC_END: + if (!pdev->multifunction) + break; - pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); - if ((ctrl & acs_flags) != acs_flags) - return false; + return pci_acs_flags_enabled(pdev, acs_flags); } + /* + * PCIe 3.0, 6.12.1.3 specifies no ACS capabilties are applicable + * to single function devices with the exception of downstream ports. + */ return true; } 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 } }; |