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Merge branch 'pci/msi' into next 

* pci/msi:
  PCI/MSI: Assume MSIs use real Requester ID, not an alias
This commit is contained in:
Bjorn Helgaas 2017-09-07 13:24:18 -05:00
parent 33db87de6a 235b2c776b
commit 79ab592c70
1 changed files with 22 additions and 5 deletions
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25
drivers/pci/msi.c
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@ -1458,13 +1458,30 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
}
EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
/*
* Users of the generic MSI infrastructure expect a device to have a single ID,
* so with DMA aliases we have to pick the least-worst compromise. Devices with
* DMA phantom functions tend to still emit MSIs from the real function number,
* so we ignore those and only consider topological aliases where either the
* alias device or RID appears on a different bus number. We also make the
* reasonable assumption that bridges are walked in an upstream direction (so
* the last one seen wins), and the much braver assumption that the most likely
* case is that of PCI->PCIe so we should always use the alias RID. This echoes
* the logic from intel_irq_remapping's set_msi_sid(), which presumably works
* well enough in practice; in the face of the horrible PCIe<->PCI-X conditions
* for taking ownership all we can really do is close our eyes and hope...
*/
static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
{
u32 *pa = data;
u8 bus = PCI_BUS_NUM(*pa);
if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus)
*pa = alias;
return 0;
}
/**
* pci_msi_domain_get_msi_rid - Get the MSI requester id (RID)
* @domain: The interrupt domain
@ -1478,7 +1495,7 @@ static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
{
struct device_node *of_node;
u32 rid = 0;
u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);
pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
@ -1494,14 +1511,14 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
* @pdev: The PCI device
*
* Use the firmware data to find a device-specific MSI domain
* (i.e. not one that is ste as a default).
* (i.e. not one that is set as a default).
*
* Returns: The coresponding MSI domain or NULL if none has been found.
* Returns: The corresponding MSI domain or NULL if none has been found.
*/
struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
{
struct irq_domain *dom;
u32 rid = 0;
u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);
pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
dom = of_msi_map_get_device_domain(&pdev->dev, rid);