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>
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@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void)
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else
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return 0;
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}
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#if IS_ENABLED(CONFIG_VMD)
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struct pci_dev *pci_real_dma_dev(struct pci_dev *dev)
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{
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if (is_vmd(dev->bus))
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return to_pci_sysdata(dev->bus)->vmd_dev;
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return dev;
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}
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#endif
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@ -6033,7 +6033,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
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return (dev1->dma_alias_mask &&
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test_bit(dev2->devfn, dev1->dma_alias_mask)) ||
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(dev2->dma_alias_mask &&
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test_bit(dev1->devfn, dev2->dma_alias_mask));
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test_bit(dev1->devfn, dev2->dma_alias_mask)) ||
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pci_real_dma_dev(dev1) == dev2 ||
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pci_real_dma_dev(dev2) == dev1;
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}
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bool pci_device_is_present(struct pci_dev *pdev)
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@ -6057,6 +6059,21 @@ void pci_ignore_hotplug(struct pci_dev *dev)
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}
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EXPORT_SYMBOL_GPL(pci_ignore_hotplug);
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/**
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* pci_real_dma_dev - Get PCI DMA device for PCI device
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* @dev: the PCI device that may have a PCI DMA alias
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*
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* Permits the platform to provide architecture-specific functionality to
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* devices needing to alias DMA to another PCI device on another PCI bus. If
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* the PCI device is on the same bus, it is recommended to use
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* pci_add_dma_alias(). This is the default implementation. Architecture
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* implementations can override this.
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*/
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struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev)
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{
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return dev;
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}
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resource_size_t __weak pcibios_default_alignment(void)
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{
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return 0;
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@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
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struct pci_bus *bus;
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int ret;
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/*
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* The device may have an explicit alias requester ID for DMA where the
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* requester is on another PCI bus.
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*/
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pdev = pci_real_dma_dev(pdev);
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ret = fn(pdev, pci_dev_id(pdev), data);
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if (ret)
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return ret;
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@ -1202,6 +1202,7 @@ int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size);
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int pci_select_bars(struct pci_dev *dev, unsigned long flags);
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bool pci_device_is_present(struct pci_dev *pdev);
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void pci_ignore_hotplug(struct pci_dev *dev);
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struct pci_dev *pci_real_dma_dev(struct pci_dev *dev);
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int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,
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irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,
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