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PCI/MSI: Add pci_enable_msi_range() and pci_enable_msix_range()

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This adds pci_enable_msi_range(), which supersedes the pci_enable_msi()
and pci_enable_msi_block() MSI interfaces.

It also adds pci_enable_msix_range(), which supersedes the
pci_enable_msix() MSI-X interface.

The old interfaces have three categories of return values:

    negative: failure; caller should not retry
    positive: failure; value indicates number of interrupts that *could*
	have been allocated, and caller may retry with a smaller request
    zero: success; at least as many interrupts allocated as requested

It is error-prone to handle these three cases correctly in drivers.

The new functions return either a negative error code or a number of
successfully allocated MSI/MSI-X interrupts, which is expected to lead to
clearer device driver code.

pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist
unchanged, but are deprecated and may be removed after callers are updated.

[bhelgaas: tweak changelog]
Suggested-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Alexander Gordeev
2013-12-30 08:28:16 +01:00
committed by Bjorn Helgaas
parent ff1aa430a2
commit 302a2523c2
3 changed files with 273 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
include/linux/pci.h
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@@ -1193,6 +1193,17 @@ static inline int pci_msi_enabled(void)
{
return 0;
}
static inline int pci_enable_msi_range(struct pci_dev *dev, int minvec,
int maxvec)
{
return -ENOSYS;
}
static inline int pci_enable_msix_range(struct pci_dev *dev,
struct msix_entry *entries, int minvec, int maxvec)
{
return -ENOSYS;
}
#else
int pci_msi_vec_count(struct pci_dev *dev);
int pci_enable_msi_block(struct pci_dev *dev, int nvec);
@@ -1205,6 +1216,9 @@ void pci_disable_msix(struct pci_dev *dev);
void msi_remove_pci_irq_vectors(struct pci_dev *dev);
void pci_restore_msi_state(struct pci_dev *dev);
int pci_msi_enabled(void);
int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec);
int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
int minvec, int maxvec);
#endif
#ifdef CONFIG_PCIEPORTBUS