PCI: Add DMA alias quirk for Intel VCA NTB

Intel Visual Compute Accelerator (VCA) is a family of PCIe add-in devices
exposing computational units via Non Transparent Bridges (NTB, PEX 87xx).

Similarly to MIC x200, we need to add DMA aliases to allow buffer access
when IOMMU is enabled.

Add aliases to allow computational unit access to host memory.  These
aliases mark the whole VCA device as one IOMMU group.

All possible slot numbers (0x20) are used, since we are unable to tell what
slot is used on other side.  This quirk is intended for both host and
computational unit sides.  The VCA devices have up to five functions: four
for DMA channels and one additional.

Link: https://lore.kernel.org/r/5683A335CC8BE1438C3C30C49DCC38DF637CED8E@IRSMSX102.ger.corp.intel.com
Signed-off-by: Slawomir Pawlowski <[email protected]>
Signed-off-by: Przemek Kitszel <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>

Author: spawlows

drivers/pci/quirks.c

@@ -4080,6 +4080,40 @@ static void quirk_mic_x200_dma_alias(struct pci_dev *pdev)
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2260, quirk_mic_x200_dma_alias);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2264, quirk_mic_x200_dma_alias);
 
+/*
+ * Intel Visual Compute Accelerator (VCA) is a family of PCIe add-in devices
+ * exposing computational units via Non Transparent Bridges (NTB, PEX 87xx).
+ *
+ * Similarly to MIC x200, we need to add DMA aliases to allow buffer access
+ * when IOMMU is enabled.  These aliases allow computational unit access to
+ * host memory.  These aliases mark the whole VCA device as one IOMMU
+ * group.
+ *
+ * All possible slot numbers (0x20) are used, since we are unable to tell
+ * what slot is used on other side.  This quirk is intended for both host
+ * and computational unit sides.  The VCA devices have up to five functions
+ * (four for DMA channels and one additional).
+ */
+static void quirk_pex_vca_alias(struct pci_dev *pdev)
+{
+	const unsigned int num_pci_slots = 0x20;
+	unsigned int slot;
+
+	for (slot = 0; slot < num_pci_slots; slot++) {
+		pci_add_dma_alias(pdev, PCI_DEVFN(slot, 0x0));
+		pci_add_dma_alias(pdev, PCI_DEVFN(slot, 0x1));
+		pci_add_dma_alias(pdev, PCI_DEVFN(slot, 0x2));
+		pci_add_dma_alias(pdev, PCI_DEVFN(slot, 0x3));
+		pci_add_dma_alias(pdev, PCI_DEVFN(slot, 0x4));
+	}
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2954, quirk_pex_vca_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2955, quirk_pex_vca_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2956, quirk_pex_vca_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2958, quirk_pex_vca_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2959, quirk_pex_vca_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x295A, quirk_pex_vca_alias);
+
 /*
  * The IOMMU and interrupt controller on Broadcom Vulcan/Cavium ThunderX2 are
  * associated not at the root bus, but at a bridge below. This quirk avoids