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>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c393dff..7f4e806 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1202,6 +1202,7 @@ int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size);
int pci_select_bars(struct pci_dev *dev, unsigned long flags);
bool pci_device_is_present(struct pci_dev *pdev);
void pci_ignore_hotplug(struct pci_dev *dev);
+struct pci_dev *pci_real_dma_dev(struct pci_dev *dev);
int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,
irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,