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.
Add helper pci_add_dma_alias_range that can alias a range of devfns in
dma_alias_mask.
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.
Signed-off-by: James Sewart <jamessewart@xxxxxxxxxx>
---
drivers/pci/pci.c | 29 ++++++++++++++++++++++-------
drivers/pci/quirks.c | 15 +++++++++++++++
include/linux/pci.h | 1 +
3 files changed, 38 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a97e2571a527..f502af1b5d10 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5854,6 +5854,18 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
return 0;
}
+int _pci_add_dma_alias_range(struct pci_dev *dev, u8 devfn_from, int len)
+{
+ if (!dev->dma_alias_mask)
+ dev->dma_alias_mask = bitmap_zalloc(U8_MAX, GFP_KERNEL);
+ if (!dev->dma_alias_mask) {
+ pci_warn(dev, "Unable to allocate DMA alias mask\n");
+ return -ENOMEM;
+ }
+ bitmap_set(dev->dma_alias_mask, devfn_from, len);
+ return 0;
+}
+
/**
* pci_add_dma_alias - Add a DMA devfn alias for a device
* @dev: the PCI device for which alias is added
@@ -5875,18 +5887,21 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
*/
void pci_add_dma_alias(struct pci_dev *dev, u8 devfn)
{
- if (!dev->dma_alias_mask)
- dev->dma_alias_mask = bitmap_zalloc(U8_MAX, GFP_KERNEL);
- if (!dev->dma_alias_mask) {
- pci_warn(dev, "Unable to allocate DMA alias mask\n");
+ if (_pci_add_dma_alias_range(dev, devfn, 1) != 0)
return;
- }
-
- set_bit(devfn, dev->dma_alias_mask);
pci_info(dev, "Enabling fixed DMA alias to %02x.%d\n",
PCI_SLOT(devfn), PCI_FUNC(devfn));
}
+void pci_add_dma_alias_range(struct pci_dev *dev, u8 devfn_from, int len)
+{
+ int devfn_to = devfn_from + len - 1;
+ if (_pci_add_dma_alias_range(dev, devfn_from, len) != 0)
+ return;
+ pci_info(dev, "Enabling fixed DMA alias for devfn range from %02x.%d to %02x.%d\n",
+ PCI_SLOT(devfn_from), PCI_FUNC(devfn_from), PCI_SLOT(devfn_to), PCI_FUNC(devfn_to));
+}
+
bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
{
return (dev1->dma_alias_mask &&
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 320255e5e8f8..1ed230f739a4 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_range(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
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1a6cf19eac2d..6765f3d0102b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2324,6 +2324,7 @@ static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev)
#endif
void pci_add_dma_alias(struct pci_dev *dev, u8 devfn);
+void pci_add_dma_alias_range(struct pci_dev *dev, u8 devfn_from, int len);
bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2);
int pci_for_each_dma_alias(struct pci_dev *pdev,
int (*fn)(struct pci_dev *pdev,
--
2.24.0
