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PCI: Provide sensible IRQ vector alloc/free routines

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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>
This commit is contained in:
Christoph Hellwig
2016-07-12 18:20:17 +09:00
committed by Bjorn Helgaas
parent 3ac020e0ca
commit aff171641d
3 changed files with 192 additions and 391 deletions
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27
include/linux/pci.h
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@@ -1237,6 +1237,10 @@ resource_size_t pcibios_iov_resource_alignment(struct pci_dev *dev, int resno);
int pci_set_vga_state(struct pci_dev *pdev, bool decode,
unsigned int command_bits, u32 flags);
#define PCI_IRQ_NOLEGACY (1 << 0) /* don't use legacy interrupts */
#define PCI_IRQ_NOMSI (1 << 1) /* don't use MSI interrupts */
#define PCI_IRQ_NOMSIX (1 << 2) /* don't use MSI-X interrupts */
/* kmem_cache style wrapper around pci_alloc_consistent() */
#include <linux/pci-dma.h>
@@ -1284,6 +1288,11 @@ static inline int pci_enable_msix_exact(struct pci_dev *dev,
return rc;
return 0;
}
int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
unsigned int max_vecs, unsigned int flags);
void pci_free_irq_vectors(struct pci_dev *dev);
int pci_irq_vector(struct pci_dev *dev, unsigned int nr);
#else
static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
static inline void pci_msi_shutdown(struct pci_dev *dev) { }
@@ -1307,6 +1316,24 @@ static inline int pci_enable_msix_range(struct pci_dev *dev,
static inline int pci_enable_msix_exact(struct pci_dev *dev,
struct msix_entry *entries, int nvec)
{ return -ENOSYS; }
static inline int pci_alloc_irq_vectors(struct pci_dev *dev,
unsigned int min_vecs, unsigned int max_vecs,
unsigned int flags)
{
if (min_vecs > 1)
return -EINVAL;
return 1;
}
static inline void pci_free_irq_vectors(struct pci_dev *dev)
{
}
static inline int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
{
if (WARN_ON_ONCE(nr > 0))
return -EINVAL;
return dev->irq;
}
#endif
#ifdef CONFIG_PCIEPORTBUS