diff options
| author | Jon Derrick <jonathan.derrick@intel.com> | 2020-01-21 14:37:47 +0100 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2020-01-24 21:55:26 +0100 |
| commit | 2856ba6020fc5cbf051d5a75b2abb3046072c144 (patch) | |
| tree | 0f93f7ebde7349949dcb9b711ba9537dc8c51b95 /drivers/pci/pci.c | |
| parent | x86/PCI: Expose VMD's pci_dev in struct pci_sysdata (diff) | |
| download | linux-2856ba6020fc5cbf051d5a75b2abb3046072c144.tar.xz linux-2856ba6020fc5cbf051d5a75b2abb3046072c144.zip | |
PCI: Introduce pci_real_dma_dev()
The current DMA alias implementation requires the aliased device be on the
same PCI bus as the requester ID. Add an arch-specific mechanism to point
to another PCI device when doing mapping and PCI DMA alias search. The
default case returns the actual device.
Link: https://lore.kernel.org/r/1579613871-301529-4-git-send-email-jonathan.derrick@intel.com
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e87196cc1a7f..ab2b8bcd29bf 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6033,7 +6033,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2) return (dev1->dma_alias_mask && test_bit(dev2->devfn, dev1->dma_alias_mask)) || (dev2->dma_alias_mask && - test_bit(dev1->devfn, dev2->dma_alias_mask)); + test_bit(dev1->devfn, dev2->dma_alias_mask)) || + pci_real_dma_dev(dev1) == dev2 || + pci_real_dma_dev(dev2) == dev1; } bool pci_device_is_present(struct pci_dev *pdev) @@ -6057,6 +6059,21 @@ void pci_ignore_hotplug(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_ignore_hotplug); +/** + * pci_real_dma_dev - Get PCI DMA device for PCI device + * @dev: the PCI device that may have a PCI DMA alias + * + * Permits the platform to provide architecture-specific functionality to + * devices needing to alias DMA to another PCI device on another PCI bus. If + * the PCI device is on the same bus, it is recommended to use + * pci_add_dma_alias(). This is the default implementation. Architecture + * implementations can override this. + */ +struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev) +{ + return dev; +} + resource_size_t __weak pcibios_default_alignment(void) { return 0; |