diff mbox series

[v4,2/2] PCI: Add DMA alias quirk for PLX PEX NTB

Message ID AAD9A3CA-59E4-4982-B902-7032CA96FAD1@arista.com
State New
Headers show
Series [v4,1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias | expand

Commit Message

James Sewart Nov. 29, 2019, 12:49 p.m. UTC 
The PLX PEX NTB forwards DMA transactions using Requester ID's that
don't exist as PCI devices. The devfn for a transaction is used as an
index into a lookup table storing the origin of a transaction on the
other side of the bridge.

This patch aliases all possible devfn's to the NTB device so that any
transaction coming in is governed by the mappings for the NTB.

Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: James Sewart <jamessewart@arista.com>
---
 drivers/pci/quirks.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
diff mbox series

Patch

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 0f3f5afc73fd..3a67049ca630 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5315,6 +5315,21 @@  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
 SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
 SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
 
+/*
+ * PLX NTB uses devfn proxy IDs to move TLPs between NT endpoints. These IDs
+ * are used to forward responses to the originator on the other side of the
+ * NTB. Alias all possible IDs to the NTB to permit access when the IOMMU is
+ * turned on.
+ */
+static void quirk_plx_ntb_dma_alias(struct pci_dev *pdev)
+{
+	pci_info(pdev, "Setting PLX NTB proxy ID aliases\n");
+	/* PLX NTB may use all 256 devfns */
+	pci_add_dma_alias(pdev, 0, 256);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x87b0, quirk_plx_ntb_dma_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x87b1, quirk_plx_ntb_dma_alias);
+
 /*
  * On Lenovo Thinkpad P50 SKUs with a Nvidia Quadro M1000M, the BIOS does
  * not always reset the secondary Nvidia GPU between reboots if the system