There are a few broken devices that use the requester ID of a different
function in the slot for their DMA. To handle these, add a bitmap to
struct pci_dev (using an alignment gap) that quirks can populate. As
we iterate over the device and bus DMA aliases, also iterate over any
bits in the map.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/pci/search.c | 21 +++++++++++++++++++++
include/linux/pci.h | 2 ++
2 files changed, 23 insertions(+)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 5601cdb..ad698b2 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -37,6 +37,27 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
if (ret)
return ret;
+ /*
+ * dma_func_alias provides a bitmap of other function numbers on
+ * this same PCI slot to use as DMA aliases.
+ */
+ if (unlikely(pdev->dma_func_alias)) {
+ u8 map = pdev->dma_func_alias & ~(1 << PCI_FUNC(pdev->devfn));
+ int func;
+
+ for (func = 0; map && func < 8; func++, map >>= 1) {
+ if (!(map & 1))
+ continue;
+
+ ret = fn(pdev,
+ PCI_DEVID(pdev->bus->number,
+ PCI_DEVFN(PCI_SLOT(pdev->devfn),
+ func)), 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 14b074b..b4c97d2 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -268,6 +268,8 @@ 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_func_alias; /* bitmap of functions used as DMA
+ aliases for this device */
struct pci_driver *driver; /* which driver has allocated this device */
u64 dma_mask; /* Mask of the bits of bus address this
--
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