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author | Christoph Hellwig <hch@lst.de> | 2016-07-12 18:20:17 +0900 |
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committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-07-21 15:50:07 -0500 |
commit | aff171641d181ea573380efc3f559c9de4741fc5 (patch) | |
tree | 4db964cfabf120e9e9f1cba6f8d1707ae5bc8159 /drivers/pci/msi.c | |
parent | 3ac020e0ca8beff9b695f9866a06d50c09c602d6 (diff) | |
download | linux-stable-aff171641d181ea573380efc3f559c9de4741fc5.tar.gz linux-stable-aff171641d181ea573380efc3f559c9de4741fc5.tar.bz2 linux-stable-aff171641d181ea573380efc3f559c9de4741fc5.zip |
PCI: Provide sensible IRQ vector alloc/free routines
Add a function to allocate and free a range of interrupt vectors, using
MSI-X, MSI or legacy vectors (in that order) based on the capabilities of
the underlying device and PCIe complex.
Additionally a new helper is provided to get the Linux IRQ number for given
device-relative vector so that the drivers don't need to allocate their own
arrays to keep track of the vectors for the multi vector MSI-X case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alexander Gordeev <agordeev@redhat.com>
Diffstat (limited to 'drivers/pci/msi.c')
-rw-r--r-- | drivers/pci/msi.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 98ace67c5f4d..5e5ab478ea7d 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -4,6 +4,7 @@ * * Copyright (C) 2003-2004 Intel * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com) + * Copyright (C) 2016 Christoph Hellwig. */ #include <linux/err.h> @@ -1121,6 +1122,94 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, } EXPORT_SYMBOL(pci_enable_msix_range); +/** + * pci_alloc_irq_vectors - allocate multiple IRQs for a device + * @dev: PCI device to operate on + * @min_vecs: minimum number of vectors required (must be >= 1) + * @max_vecs: maximum (desired) number of vectors + * @flags: flags or quirks for the allocation + * + * Allocate up to @max_vecs interrupt vectors for @dev, using MSI-X or MSI + * vectors if available, and fall back to a single legacy vector + * if neither is available. Return the number of vectors allocated, + * (which might be smaller than @max_vecs) if successful, or a negative + * error code on error. If less than @min_vecs interrupt vectors are + * available for @dev the function will fail with -ENOSPC. + * + * To get the Linux IRQ number used for a vector that can be passed to + * request_irq() use the pci_irq_vector() helper. + */ +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs, + unsigned int max_vecs, unsigned int flags) +{ + int vecs = -ENOSPC; + + if (!(flags & PCI_IRQ_NOMSIX)) { + vecs = pci_enable_msix_range(dev, NULL, min_vecs, max_vecs); + if (vecs > 0) + return vecs; + } + + if (!(flags & PCI_IRQ_NOMSI)) { + vecs = pci_enable_msi_range(dev, min_vecs, max_vecs); + if (vecs > 0) + return vecs; + } + + /* use legacy irq if allowed */ + if (!(flags & PCI_IRQ_NOLEGACY) && min_vecs == 1) + return 1; + return vecs; +} +EXPORT_SYMBOL(pci_alloc_irq_vectors); + +/** + * pci_free_irq_vectors - free previously allocated IRQs for a device + * @dev: PCI device to operate on + * + * Undoes the allocations and enabling in pci_alloc_irq_vectors(). + */ +void pci_free_irq_vectors(struct pci_dev *dev) +{ + pci_disable_msix(dev); + pci_disable_msi(dev); +} +EXPORT_SYMBOL(pci_free_irq_vectors); + +/** + * pci_irq_vector - return Linux IRQ number of a device vector + * @dev: PCI device to operate on + * @nr: device-relative interrupt vector index (0-based). + */ +int pci_irq_vector(struct pci_dev *dev, unsigned int nr) +{ + if (dev->msix_enabled) { + struct msi_desc *entry; + int i = 0; + + for_each_pci_msi_entry(entry, dev) { + if (i == nr) + return entry->irq; + i++; + } + WARN_ON_ONCE(1); + return -EINVAL; + } + + if (dev->msi_enabled) { + struct msi_desc *entry = first_pci_msi_entry(dev); + + if (WARN_ON_ONCE(nr >= entry->nvec_used)) + return -EINVAL; + } else { + if (WARN_ON_ONCE(nr > 0)) + return -EINVAL; + } + + return dev->irq + nr; +} +EXPORT_SYMBOL(pci_irq_vector); + struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc) { return to_pci_dev(desc->dev); |