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PCI/MSI: Allow the MSI domain to be device-specific

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So far, we've always considered that for a given PCI device, its
MSI controller was either set by the architecture-specific
pcibios hook, or simply inherited from the host bridge.

This doesn't cover things like firmware-defined topologies like
msi-map (DT) or IORT (ACPI), which can provide information about
which MSI controller to use on a per-device basis.

This patch adds the necessary hook into the MSI code to allow this
feature, and provides the msi-map functionnality as a first
implementation.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2015-10-02 14:43:06 +01:00
parent 098259eb16
commit 54fa97eeb9
3 changed files with 31 additions and 0 deletions
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17
drivers/pci/msi.c
View file

@ -1359,4 +1359,21 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
return rid;
}
/**
* pci_msi_get_device_domain - Get the MSI domain for a given PCI device
* @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).
*
* Returns: The coresponding MSI domain or NULL if none has been found.
*/
struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
{
u32 rid = 0;
pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
return of_msi_map_get_device_domain(&pdev->dev, rid);
}
#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */

8
drivers/pci/probe.c
View file

@ -1639,6 +1639,14 @@ static struct irq_domain *pci_dev_msi_domain(struct pci_dev *dev)
if (d)
return d;
/*
* Let's see if we have a firmware interface able to provide
* the domain.
*/
d = pci_msi_get_device_domain(dev);
if (d)
return d;
return NULL;
}

6
include/linux/msi.h
View file

@ -295,6 +295,12 @@ irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
int pci_msi_domain_check_cap(struct irq_domain *domain,
struct msi_domain_info *info, struct device *dev);
u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
#else
static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
{
return NULL;
}
#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
#endif /* LINUX_MSI_H */