PCI/MSI: Add pci_enable_msi() documentation back
We deprecated pci_enable_msi() in 302a2523c2
("PCI/MSI: Add
pci_enable_msi_range() and pci_enable_msix_range()").
But we changed our minds after noticing that:
- pci_enable_msi() doesn't have confusing return values like
pci_enable_msi_block() and pci_enable_msix() did, and
- pci_enable_msi() has a hundred or so callers that we don't want to
change.
This adds back the pci_enable_msi() documentation.
[bhelgaas: changelog]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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@ -82,7 +82,19 @@ Most of the hard work is done for the driver in the PCI layer. It simply
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has to request that the PCI layer set up the MSI capability for this
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has to request that the PCI layer set up the MSI capability for this
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device.
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device.
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4.2.1 pci_enable_msi_range
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4.2.1 pci_enable_msi
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int pci_enable_msi(struct pci_dev *dev)
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A successful call allocates ONE interrupt to the device, regardless
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of how many MSIs the device supports. The device is switched from
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pin-based interrupt mode to MSI mode. The dev->irq number is changed
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to a new number which represents the message signaled interrupt;
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consequently, this function should be called before the driver calls
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request_irq(), because an MSI is delivered via a vector that is
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different from the vector of a pin-based interrupt.
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4.2.2 pci_enable_msi_range
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int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
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int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
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@ -158,7 +170,12 @@ static int foo_driver_enable_single_msi(struct pci_dev *pdev)
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return pci_enable_msi_range(pdev, 1, 1);
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return pci_enable_msi_range(pdev, 1, 1);
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}
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}
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4.2.2 pci_disable_msi
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Note, unlike pci_enable_msi() function, which could be also used to
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enable the single MSI mode, pci_enable_msi_range() returns either a
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negative errno or 1 (not negative errno or 0 - as pci_enable_msi()
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does).
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4.2.3 pci_disable_msi
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void pci_disable_msi(struct pci_dev *dev)
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void pci_disable_msi(struct pci_dev *dev)
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@ -172,7 +189,7 @@ on any interrupt for which it previously called request_irq().
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Failure to do so results in a BUG_ON(), leaving the device with
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Failure to do so results in a BUG_ON(), leaving the device with
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MSI enabled and thus leaking its vector.
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MSI enabled and thus leaking its vector.
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4.2.3 pci_msi_vec_count
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4.2.4 pci_msi_vec_count
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int pci_msi_vec_count(struct pci_dev *dev)
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int pci_msi_vec_count(struct pci_dev *dev)
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