diff options
| author | Jon Derrick <jonathan.derrick@intel.com> | 2020-01-21 06:37:47 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2020-01-24 14:55:26 -0600 |
| commit | 2856ba6020fc5cbf051d5a75b2abb3046072c144 (patch) | |
| tree | 0f93f7ebde7349949dcb9b711ba9537dc8c51b95 | |
| parent | 34067c56fa177d3582695da8e3e162ef78cd0371 (diff) | |
| download | lwn-2856ba6020fc5cbf051d5a75b2abb3046072c144.tar.gz lwn-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>
| -rw-r--r-- | arch/x86/pci/common.c | 10 | ||||
| -rw-r--r-- | drivers/pci/pci.c | 19 | ||||
| -rw-r--r-- | drivers/pci/search.c | 6 | ||||
| -rw-r--r-- | include/linux/pci.h | 1 |
4 files changed, 35 insertions, 1 deletions
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 1e59df041456..fe21a5c557e6 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void) else return 0; } + +#if IS_ENABLED(CONFIG_VMD) +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev) +{ + if (is_vmd(dev->bus)) + return to_pci_sysdata(dev->bus)->vmd_dev; + + return dev; +} +#endif 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; diff --git a/drivers/pci/search.c b/drivers/pci/search.c index bade14002fd8..efdb8b56035f 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, struct pci_bus *bus; int ret; + /* + * The device may have an explicit alias requester ID for DMA where the + * requester is on another PCI bus. + */ + pdev = pci_real_dma_dev(pdev); + ret = fn(pdev, pci_dev_id(pdev), data); if (ret) return ret; diff --git a/include/linux/pci.h b/include/linux/pci.h index c393dff2d66f..7f4e80666972 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, |