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PCI/MSI: Remove pci_enable_msi_block_auto()

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The new pci_msi_vec_count() interface makes pci_enable_msi_block_auto()
superfluous.

Drivers can use pci_msi_vec_count() to learn the maximum number of MSIs
supported by the device, and then call pci_enable_msi_block().

pci_enable_msi_block_auto() was introduced recently, and its only user is
the AHCI driver, which is also updated by this change.

Signed-off-by: Alexander Gordeev <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Tejun Heo <[email protected]>
This commit is contained in:
Alexander Gordeev 2013-12-30 08:28:14 +01:00 • committed by Bjorn Helgaas
commit 7b92b4f61e
4 changed files with 41 additions and 86 deletions
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39
Documentation/PCI/MSI-HOWTO.txt
View file

@ -127,49 +127,22 @@ on the number of vectors that can be allocated; pci_enable_msi_block()
returns as soon as it finds any constraint that doesn't allow the
call to succeed.
4.2.3 pci_enable_msi_block_auto
int pci_enable_msi_block_auto(struct pci_dev *dev, int *count)
This variation on pci_enable_msi() call allows a device driver to request
the maximum possible number of MSIs. The MSI specification only allows
interrupts to be allocated in powers of two, up to a maximum of 2^5 (32).
If this function returns a positive number, it indicates that it has
succeeded and the returned value is the number of allocated interrupts. In
this case, the function enables MSI on this device and updates dev->irq to
be the lowest of the new interrupts assigned to it. The other interrupts
assigned to the device are in the range dev->irq to dev->irq + returned
value - 1.
If this function returns a negative number, it indicates an error and
the driver should not attempt to request any more MSI interrupts for
this device.
If the device driver needs to know the number of interrupts the device
supports it can pass the pointer count where that number is stored. The
device driver must decide what action to take if pci_enable_msi_block_auto()
succeeds, but returns a value less than the number of interrupts supported.
If the device driver does not need to know the number of interrupts
supported, it can set the pointer count to NULL.
4.2.4 pci_disable_msi
4.2.3 pci_disable_msi
void pci_disable_msi(struct pci_dev *dev)
This function should be used to undo the effect of pci_enable_msi() or
pci_enable_msi_block() or pci_enable_msi_block_auto(). Calling it restores
dev->irq to the pin-based interrupt number and frees the previously
allocated message signaled interrupt(s). The interrupt may subsequently be
assigned to another device, so drivers should not cache the value of
dev->irq.
pci_enable_msi_block(). Calling it restores dev->irq to the pin-based
interrupt number and frees the previously allocated message signaled
interrupt(s). The interrupt may subsequently be assigned to another
device, so drivers should not cache the value of dev->irq.
Before calling this function, a device driver must always call free_irq()
on any interrupt for which it previously called request_irq().
Failure to do so results in a BUG_ON(), leaving the device with
MSI enabled and thus leaking its vector.
4.2.5 pci_msi_vec_count
4.2.4 pci_msi_vec_count
int pci_msi_vec_count(struct pci_dev *dev)