diff options
| -rw-r--r-- | drivers/pci/pci.h | 4 | ||||
| -rw-r--r-- | drivers/pci/probe.c | 22 | ||||
| -rw-r--r-- | drivers/pci/quirks.c | 55 |
3 files changed, 79 insertions, 2 deletions
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index c358e7a07f3f..70808c168fb9 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -225,6 +225,10 @@ enum pci_bar_type { int pci_configure_extended_tags(struct pci_dev *dev, void *ign); bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, int crs_timeout); +bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, + int crs_timeout); +int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *pl, int crs_timeout); + int pci_setup_device(struct pci_dev *dev); int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, struct resource *res, unsigned int reg); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index ac876e32de4b..7c0c8ab94bcf 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2156,8 +2156,8 @@ static bool pci_bus_wait_crs(struct pci_bus *bus, int devfn, u32 *l, return true; } -bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, - int timeout) +bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, + int timeout) { if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l)) return false; @@ -2172,6 +2172,24 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, return true; } + +bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, + int timeout) +{ +#ifdef CONFIG_PCI_QUIRKS + struct pci_dev *bridge = bus->self; + + /* + * Certain IDT switches have an issue where they improperly trigger + * ACS Source Validation errors on completions for config reads. + */ + if (bridge && bridge->vendor == PCI_VENDOR_ID_IDT && + bridge->device == 0x80b5) + return pci_idt_bus_quirk(bus, devfn, l, timeout); +#endif + + return pci_bus_generic_read_dev_vendor_id(bus, devfn, l, timeout); +} EXPORT_SYMBOL(pci_bus_read_dev_vendor_id); /* diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index f439de848658..cab2d5f922a9 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4753,3 +4753,58 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMD, PCI_ANY_ID, PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda); DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda); + +/* + * Some IDT switches incorrectly flag an ACS Source Validation error on + * completions for config read requests even though PCIe r4.0, sec + * 6.12.1.1, says that completions are never affected by ACS Source + * Validation. Here's the text of IDT 89H32H8G3-YC, erratum #36: + * + * Item #36 - Downstream port applies ACS Source Validation to Completions + * Section 6.12.1.1 of the PCI Express Base Specification 3.1 states that + * completions are never affected by ACS Source Validation. However, + * completions received by a downstream port of the PCIe switch from a + * device that has not yet captured a PCIe bus number are incorrectly + * dropped by ACS Source Validation by the switch downstream port. + * + * The workaround suggested by IDT is to issue a config write to the + * downstream device before issuing the first config read. This allows the + * downstream device to capture its bus and device numbers (see PCIe r4.0, + * sec 2.2.9), thus avoiding the ACS error on the completion. + * + * However, we don't know when the device is ready to accept the config + * write, so we do config reads until we receive a non-Config Request Retry + * Status, then do the config write. + * + * To avoid hitting the erratum when doing the config reads, we disable ACS + * SV around this process. + */ +int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *l, int timeout) +{ + int pos; + u16 ctrl = 0; + bool found; + struct pci_dev *bridge = bus->self; + + pos = pci_find_ext_capability(bridge, PCI_EXT_CAP_ID_ACS); + + /* Disable ACS SV before initial config reads */ + if (pos) { + pci_read_config_word(bridge, pos + PCI_ACS_CTRL, &ctrl); + if (ctrl & PCI_ACS_SV) + pci_write_config_word(bridge, pos + PCI_ACS_CTRL, + ctrl & ~PCI_ACS_SV); + } + + found = pci_bus_generic_read_dev_vendor_id(bus, devfn, l, timeout); + + /* Write Vendor ID (read-only) so the endpoint latches its bus/dev */ + if (found) + pci_bus_write_config_word(bus, devfn, PCI_VENDOR_ID, 0); + + /* Re-enable ACS_SV if it was previously enabled */ + if (ctrl & PCI_ACS_SV) + pci_write_config_word(bridge, pos + PCI_ACS_CTRL, ctrl); + + return found; +} |