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Commit 31c2b815 authored May 22, 2014 by Alex Williamson Committed by Bjorn Helgaas May 28, 2014

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 <linux@horizon.com>
Tested-by: Pat Erley <pat-lkml@erley.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

parent 6b121592

drivers/pci/search.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -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;

include/linux/pci.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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