From 31c2b8153c58f11ddb80dfd392c16f13c2d709c6 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 22 May 2014 17:07:43 -0600 Subject: [PATCH] PCI: Add support for DMA alias quirks Some devices are broken and use a requester ID other than their physical devfn. Add a byte, using an existing gap in the pci_dev structure, to store an alternate "alias" devfn. A bit in the dev_flags tells us when this is valid. We then add the alias as one more step in the pci_for_each_dma_alias() iterator. Tested-by: George Spelvin Tested-by: Pat Erley Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- drivers/pci/search.c | 11 +++++++++++ include/linux/pci.h | 3 +++ 2 files changed, 14 insertions(+) diff --git a/drivers/pci/search.c b/drivers/pci/search.c index 5601cdb8bbb3..2c19f3f40621 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -37,6 +37,17 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, if (ret) return ret; + /* + * If the device is broken and uses an alias requester ID for + * DMA, iterate over that too. + */ + if (unlikely(pdev->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN)) { + ret = fn(pdev, PCI_DEVID(pdev->bus->number, + pdev->dma_alias_devfn), data); + if (ret) + return ret; + } + for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) { struct pci_dev *tmp; diff --git a/include/linux/pci.h b/include/linux/pci.h index 545903df00dc..9d4035c276f4 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -171,6 +171,8 @@ enum pci_dev_flags { PCI_DEV_FLAGS_ASSIGNED = (__force pci_dev_flags_t) (1 << 2), /* Flag for quirk use to store if quirk-specific ACS is enabled */ PCI_DEV_FLAGS_ACS_ENABLED_QUIRK = (__force pci_dev_flags_t) (1 << 3), + /* Flag to indicate the device uses dma_alias_devfn */ + PCI_DEV_FLAGS_DMA_ALIAS_DEVFN = (__force pci_dev_flags_t) (1 << 4), }; enum pci_irq_reroute_variant { @@ -268,6 +270,7 @@ struct pci_dev { u8 rom_base_reg; /* which config register controls the ROM */ u8 pin; /* which interrupt pin this device uses */ u16 pcie_flags_reg; /* cached PCIe Capabilities Register */ + u8 dma_alias_devfn;/* devfn of DMA alias, if any */ struct pci_driver *driver; /* which driver has allocated this device */ u64 dma_mask; /* Mask of the bits of bus address this