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>
This commit is contained in:
Christoph Hellwig
Bjorn Helgaas
Родитель
3ac020e0ca
Коммит
aff171641d
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@ -78,422 +78,107 @@ CONFIG_PCI_MSI option.
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4.2 Using MSI
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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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Most of the hard work is done for the driver in the PCI layer. The driver
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simply has to request that the PCI layer set up the MSI capability for this
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device.
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4.2.1 pci_enable_msi
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To automatically use MSI or MSI-X interrupt vectors, use the following
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function:
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int pci_enable_msi(struct pci_dev *dev)
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int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
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unsigned int max_vecs, unsigned int flags);
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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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which allocates up to max_vecs interrupt vectors for a PCI device. It
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returns the number of vectors allocated or a negative error. If the device
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has a requirements for a minimum number of vectors the driver can pass a
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min_vecs argument set to this limit, and the PCI core will return -ENOSPC
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if it can't meet the minimum number of vectors.
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4.2.2 pci_enable_msi_range
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The flags argument should normally be set to 0, but can be used to pass the
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PCI_IRQ_NOMSI and PCI_IRQ_NOMSIX flag in case a device claims to support
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MSI or MSI-X, but the support is broken, or to pass PCI_IRQ_NOLEGACY in
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case the device does not support legacy interrupt lines.
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int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
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To get the Linux IRQ numbers passed to request_irq() and free_irq() and the
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vectors, use the following function:
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This function allows a device driver to request any number of MSI
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interrupts within specified range from 'minvec' to 'maxvec'.
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int pci_irq_vector(struct pci_dev *dev, unsigned int nr);
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If this function returns a positive number it indicates the number of
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MSI interrupts that have been successfully allocated. In this case
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the device is switched from pin-based interrupt mode to MSI mode and
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updates dev->irq to be the lowest of the new interrupts assigned to it.
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The other interrupts assigned to the device are in the range dev->irq
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to dev->irq + returned value - 1. Device driver can use the returned
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number of successfully allocated MSI interrupts to further allocate
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and initialize device resources.
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Any allocated resources should be freed before removing the device using
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the following function:
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If this function returns a negative number, it indicates an error and
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the driver should not attempt to request any more MSI interrupts for
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this device.
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void pci_free_irq_vectors(struct pci_dev *dev);
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This function should be called before the driver calls request_irq(),
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because MSI interrupts are delivered via vectors that are different
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from the vector of a pin-based interrupt.
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If a device supports both MSI-X and MSI capabilities, this API will use the
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MSI-X facilities in preference to the MSI facilities. MSI-X supports any
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number of interrupts between 1 and 2048. In contrast, MSI is restricted to
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a maximum of 32 interrupts (and must be a power of two). In addition, the
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MSI interrupt vectors must be allocated consecutively, so the system might
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not be able to allocate as many vectors for MSI as it could for MSI-X. On
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some platforms, MSI interrupts must all be targeted at the same set of CPUs
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whereas MSI-X interrupts can all be targeted at different CPUs.
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It is ideal if drivers can cope with a variable number of MSI interrupts;
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there are many reasons why the platform may not be able to provide the
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exact number that a driver asks for.
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If a device supports neither MSI-X or MSI it will fall back to a single
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legacy IRQ vector.
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There could be devices that can not operate with just any number of MSI
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interrupts within a range. See chapter 4.3.1.3 to get the idea how to
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handle such devices for MSI-X - the same logic applies to MSI.
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The typical usage of MSI or MSI-X interrupts is to allocate as many vectors
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as possible, likely up to the limit supported by the device. If nvec is
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larger than the number supported by the device it will automatically be
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capped to the supported limit, so there is no need to query the number of
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vectors supported beforehand:
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4.2.1.1 Maximum possible number of MSI interrupts
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The typical usage of MSI interrupts is to allocate as many vectors as
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possible, likely up to the limit returned by pci_msi_vec_count() function:
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static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
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{
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return pci_enable_msi_range(pdev, 1, nvec);
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}
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Note the value of 'minvec' parameter is 1. As 'minvec' is inclusive,
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the value of 0 would be meaningless and could result in error.
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Some devices have a minimal limit on number of MSI interrupts.
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In this case the function could look like this:
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static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
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{
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return pci_enable_msi_range(pdev, FOO_DRIVER_MINIMUM_NVEC, nvec);
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}
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4.2.1.2 Exact number of MSI interrupts
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nvec = pci_alloc_irq_vectors(pdev, 1, nvec, 0);
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if (nvec < 0)
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goto out_err;
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If a driver is unable or unwilling to deal with a variable number of MSI
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interrupts it could request a particular number of interrupts by passing
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that number to pci_enable_msi_range() function as both 'minvec' and 'maxvec'
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parameters:
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interrupts it can request a particular number of interrupts by passing that
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number to pci_alloc_irq_vectors() function as both 'min_vecs' and
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'max_vecs' parameters:
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static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec)
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{
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return pci_enable_msi_range(pdev, nvec, nvec);
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}
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ret = pci_alloc_irq_vectors(pdev, nvec, nvec, 0);
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if (ret < 0)
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goto out_err;
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Note, unlike pci_enable_msi_exact() function, which could be also used to
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enable a particular number of MSI-X interrupts, pci_enable_msi_range()
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returns either a negative errno or 'nvec' (not negative errno or 0 - as
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pci_enable_msi_exact() does).
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The most notorious example of the request type described above is enabling
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the single MSI mode for a device. It could be done by passing two 1s as
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'min_vecs' and 'max_vecs':
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4.2.1.3 Single MSI mode
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ret = pci_alloc_irq_vectors(pdev, 1, 1, 0);
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if (ret < 0)
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goto out_err;
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The most notorious example of the request type described above is
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enabling the single MSI mode for a device. It could be done by passing
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two 1s as 'minvec' and 'maxvec':
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Some devices might not support using legacy line interrupts, in which case
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the PCI_IRQ_NOLEGACY flag can be used to fail the request if the platform
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can't provide MSI or MSI-X interrupts:
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static int foo_driver_enable_single_msi(struct pci_dev *pdev)
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{
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return pci_enable_msi_range(pdev, 1, 1);
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}
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nvec = pci_alloc_irq_vectors(pdev, 1, nvec, PCI_IRQ_NOLEGACY);
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if (nvec < 0)
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goto out_err;
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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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4.3 Legacy APIs
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4.2.3 pci_enable_msi_exact
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The following old APIs to enable and disable MSI or MSI-X interrupts should
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not be used in new code:
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int pci_enable_msi_exact(struct pci_dev *dev, int nvec)
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pci_enable_msi() /* deprecated */
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pci_enable_msi_range() /* deprecated */
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pci_enable_msi_exact() /* deprecated */
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pci_disable_msi() /* deprecated */
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pci_enable_msix_range() /* deprecated */
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pci_enable_msix_exact() /* deprecated */
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pci_disable_msix() /* deprecated */
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This variation on pci_enable_msi_range() call allows a device driver to
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request exactly 'nvec' MSIs.
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Additionally there are APIs to provide the number of supported MSI or MSI-X
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vectors: pci_msi_vec_count() and pci_msix_vec_count(). In general these
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should be avoided in favor of letting pci_alloc_irq_vectors() cap the
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number of vectors. If you have a legitimate special use case for the count
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of vectors we might have to revisit that decision and add a
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pci_nr_irq_vectors() helper that handles MSI and MSI-X transparently.
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If this function returns a negative number, it indicates an error and
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the driver should not attempt to request any more MSI interrupts for
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this device.
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4.4 Considerations when using MSIs
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By contrast with pci_enable_msi_range() function, pci_enable_msi_exact()
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returns zero in case of success, which indicates MSI interrupts have been
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successfully allocated.
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4.2.4 pci_disable_msi
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void pci_disable_msi(struct pci_dev *dev)
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This function should be used to undo the effect of pci_enable_msi_range().
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Calling it restores dev->irq to the pin-based interrupt number and frees
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the previously allocated MSIs. The interrupts may subsequently be assigned
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to another device, so drivers should not cache the value of dev->irq.
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Before calling this function, a device driver must always call free_irq()
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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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MSI enabled and thus leaking its vector.
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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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This function could be used to retrieve the number of MSI vectors the
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device requested (via the Multiple Message Capable register). The MSI
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specification only allows the returned value to be a power of two,
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up to a maximum of 2^5 (32).
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If this function returns a negative number, it indicates the device is
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not capable of sending MSIs.
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If this function returns a positive number, it indicates the maximum
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number of MSI interrupt vectors that could be allocated.
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4.3 Using MSI-X
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The MSI-X capability is much more flexible than the MSI capability.
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It supports up to 2048 interrupts, each of which can be controlled
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independently. To support this flexibility, drivers must use an array of
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`struct msix_entry':
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struct msix_entry {
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u16 vector; /* kernel uses to write alloc vector */
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u16 entry; /* driver uses to specify entry */
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};
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This allows for the device to use these interrupts in a sparse fashion;
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for example, it could use interrupts 3 and 1027 and yet allocate only a
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two-element array. The driver is expected to fill in the 'entry' value
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in each element of the array to indicate for which entries the kernel
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should assign interrupts; it is invalid to fill in two entries with the
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same number.
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4.3.1 pci_enable_msix_range
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int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
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int minvec, int maxvec)
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Calling this function asks the PCI subsystem to allocate any number of
|
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MSI-X interrupts within specified range from 'minvec' to 'maxvec'.
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The 'entries' argument is a pointer to an array of msix_entry structs
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which should be at least 'maxvec' entries in size.
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On success, the device is switched into MSI-X mode and the function
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returns the number of MSI-X interrupts that have been successfully
|
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allocated. In this case the 'vector' member in entries numbered from
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0 to the returned value - 1 is populated with the interrupt number;
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the driver should then call request_irq() for each 'vector' that it
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decides to use. The device driver is responsible for keeping track of the
|
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interrupts assigned to the MSI-X vectors so it can free them again later.
|
||||
Device driver can use the returned number of successfully allocated MSI-X
|
||||
interrupts to further allocate and initialize device resources.
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|
||||
If this function returns a negative number, it indicates an error and
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||||
the driver should not attempt to allocate any more MSI-X interrupts for
|
||||
this device.
|
||||
|
||||
This function, in contrast with pci_enable_msi_range(), does not adjust
|
||||
dev->irq. The device will not generate interrupts for this interrupt
|
||||
number once MSI-X is enabled.
|
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||||
Device drivers should normally call this function once per device
|
||||
during the initialization phase.
|
||||
|
||||
It is ideal if drivers can cope with a variable number of MSI-X interrupts;
|
||||
there are many reasons why the platform may not be able to provide the
|
||||
exact number that a driver asks for.
|
||||
|
||||
There could be devices that can not operate with just any number of MSI-X
|
||||
interrupts within a range. E.g., an network adapter might need let's say
|
||||
four vectors per each queue it provides. Therefore, a number of MSI-X
|
||||
interrupts allocated should be a multiple of four. In this case interface
|
||||
pci_enable_msix_range() can not be used alone to request MSI-X interrupts
|
||||
(since it can allocate any number within the range, without any notion of
|
||||
the multiple of four) and the device driver should master a custom logic
|
||||
to request the required number of MSI-X interrupts.
|
||||
|
||||
4.3.1.1 Maximum possible number of MSI-X interrupts
|
||||
|
||||
The typical usage of MSI-X interrupts is to allocate as many vectors as
|
||||
possible, likely up to the limit returned by pci_msix_vec_count() function:
|
||||
|
||||
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
|
||||
{
|
||||
return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
|
||||
1, nvec);
|
||||
}
|
||||
|
||||
Note the value of 'minvec' parameter is 1. As 'minvec' is inclusive,
|
||||
the value of 0 would be meaningless and could result in error.
|
||||
|
||||
Some devices have a minimal limit on number of MSI-X interrupts.
|
||||
In this case the function could look like this:
|
||||
|
||||
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
|
||||
{
|
||||
return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
|
||||
FOO_DRIVER_MINIMUM_NVEC, nvec);
|
||||
}
|
||||
|
||||
4.3.1.2 Exact number of MSI-X interrupts
|
||||
|
||||
If a driver is unable or unwilling to deal with a variable number of MSI-X
|
||||
interrupts it could request a particular number of interrupts by passing
|
||||
that number to pci_enable_msix_range() function as both 'minvec' and 'maxvec'
|
||||
parameters:
|
||||
|
||||
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
|
||||
{
|
||||
return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
|
||||
nvec, nvec);
|
||||
}
|
||||
|
||||
Note, unlike pci_enable_msix_exact() function, which could be also used to
|
||||
enable a particular number of MSI-X interrupts, pci_enable_msix_range()
|
||||
returns either a negative errno or 'nvec' (not negative errno or 0 - as
|
||||
pci_enable_msix_exact() does).
|
||||
|
||||
4.3.1.3 Specific requirements to the number of MSI-X interrupts
|
||||
|
||||
As noted above, there could be devices that can not operate with just any
|
||||
number of MSI-X interrupts within a range. E.g., let's assume a device that
|
||||
is only capable sending the number of MSI-X interrupts which is a power of
|
||||
two. A routine that enables MSI-X mode for such device might look like this:
|
||||
|
||||
/*
|
||||
* Assume 'minvec' and 'maxvec' are non-zero
|
||||
*/
|
||||
static int foo_driver_enable_msix(struct foo_adapter *adapter,
|
||||
int minvec, int maxvec)
|
||||
{
|
||||
int rc;
|
||||
|
||||
minvec = roundup_pow_of_two(minvec);
|
||||
maxvec = rounddown_pow_of_two(maxvec);
|
||||
|
||||
if (minvec > maxvec)
|
||||
return -ERANGE;
|
||||
|
||||
retry:
|
||||
rc = pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
|
||||
maxvec, maxvec);
|
||||
/*
|
||||
* -ENOSPC is the only error code allowed to be analyzed
|
||||
*/
|
||||
if (rc == -ENOSPC) {
|
||||
if (maxvec == 1)
|
||||
return -ENOSPC;
|
||||
|
||||
maxvec /= 2;
|
||||
|
||||
if (minvec > maxvec)
|
||||
return -ENOSPC;
|
||||
|
||||
goto retry;
|
||||
}
|
||||
|
||||
return rc;
|
||||
}
|
||||
|
||||
Note how pci_enable_msix_range() return value is analyzed for a fallback -
|
||||
any error code other than -ENOSPC indicates a fatal error and should not
|
||||
be retried.
|
||||
|
||||
4.3.2 pci_enable_msix_exact
|
||||
|
||||
int pci_enable_msix_exact(struct pci_dev *dev,
|
||||
struct msix_entry *entries, int nvec)
|
||||
|
||||
This variation on pci_enable_msix_range() call allows a device driver to
|
||||
request exactly 'nvec' MSI-Xs.
|
||||
|
||||
If this function returns a negative number, it indicates an error and
|
||||
the driver should not attempt to allocate any more MSI-X interrupts for
|
||||
this device.
|
||||
|
||||
By contrast with pci_enable_msix_range() function, pci_enable_msix_exact()
|
||||
returns zero in case of success, which indicates MSI-X interrupts have been
|
||||
successfully allocated.
|
||||
|
||||
Another version of a routine that enables MSI-X mode for a device with
|
||||
specific requirements described in chapter 4.3.1.3 might look like this:
|
||||
|
||||
/*
|
||||
* Assume 'minvec' and 'maxvec' are non-zero
|
||||
*/
|
||||
static int foo_driver_enable_msix(struct foo_adapter *adapter,
|
||||
int minvec, int maxvec)
|
||||
{
|
||||
int rc;
|
||||
|
||||
minvec = roundup_pow_of_two(minvec);
|
||||
maxvec = rounddown_pow_of_two(maxvec);
|
||||
|
||||
if (minvec > maxvec)
|
||||
return -ERANGE;
|
||||
|
||||
retry:
|
||||
rc = pci_enable_msix_exact(adapter->pdev,
|
||||
adapter->msix_entries, maxvec);
|
||||
|
||||
/*
|
||||
* -ENOSPC is the only error code allowed to be analyzed
|
||||
*/
|
||||
if (rc == -ENOSPC) {
|
||||
if (maxvec == 1)
|
||||
return -ENOSPC;
|
||||
|
||||
maxvec /= 2;
|
||||
|
||||
if (minvec > maxvec)
|
||||
return -ENOSPC;
|
||||
|
||||
goto retry;
|
||||
} else if (rc < 0) {
|
||||
return rc;
|
||||
}
|
||||
|
||||
return maxvec;
|
||||
}
|
||||
|
||||
4.3.3 pci_disable_msix
|
||||
|
||||
void pci_disable_msix(struct pci_dev *dev)
|
||||
|
||||
This function should be used to undo the effect of pci_enable_msix_range().
|
||||
It frees the previously allocated MSI-X interrupts. The interrupts may
|
||||
subsequently be assigned to another device, so drivers should not cache
|
||||
the value of the 'vector' elements over a call to pci_disable_msix().
|
||||
|
||||
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-X enabled and thus leaking its vector.
|
||||
|
||||
4.3.3 The MSI-X Table
|
||||
|
||||
The MSI-X capability specifies a BAR and offset within that BAR for the
|
||||
MSI-X Table. This address is mapped by the PCI subsystem, and should not
|
||||
be accessed directly by the device driver. If the driver wishes to
|
||||
mask or unmask an interrupt, it should call disable_irq() / enable_irq().
|
||||
|
||||
4.3.4 pci_msix_vec_count
|
||||
|
||||
int pci_msix_vec_count(struct pci_dev *dev)
|
||||
|
||||
This function could be used to retrieve number of entries in the device
|
||||
MSI-X table.
|
||||
|
||||
If this function returns a negative number, it indicates the device is
|
||||
not capable of sending MSI-Xs.
|
||||
|
||||
If this function returns a positive number, it indicates the maximum
|
||||
number of MSI-X interrupt vectors that could be allocated.
|
||||
|
||||
4.4 Handling devices implementing both MSI and MSI-X capabilities
|
||||
|
||||
If a device implements both MSI and MSI-X capabilities, it can
|
||||
run in either MSI mode or MSI-X mode, but not both simultaneously.
|
||||
This is a requirement of the PCI spec, and it is enforced by the
|
||||
PCI layer. Calling pci_enable_msi_range() when MSI-X is already
|
||||
enabled or pci_enable_msix_range() when MSI is already enabled
|
||||
results in an error. If a device driver wishes to switch between MSI
|
||||
and MSI-X at runtime, it must first quiesce the device, then switch
|
||||
it back to pin-interrupt mode, before calling pci_enable_msi_range()
|
||||
or pci_enable_msix_range() and resuming operation. This is not expected
|
||||
to be a common operation but may be useful for debugging or testing
|
||||
during development.
|
||||
|
||||
4.5 Considerations when using MSIs
|
||||
|
||||
4.5.1 Choosing between MSI-X and MSI
|
||||
|
||||
If your device supports both MSI-X and MSI capabilities, you should use
|
||||
the MSI-X facilities in preference to the MSI facilities. As mentioned
|
||||
above, MSI-X supports any number of interrupts between 1 and 2048.
|
||||
In contrast, MSI is restricted to a maximum of 32 interrupts (and
|
||||
must be a power of two). In addition, the MSI interrupt vectors must
|
||||
be allocated consecutively, so the system might not be able to allocate
|
||||
as many vectors for MSI as it could for MSI-X. On some platforms, MSI
|
||||
interrupts must all be targeted at the same set of CPUs whereas MSI-X
|
||||
interrupts can all be targeted at different CPUs.
|
||||
|
||||
4.5.2 Spinlocks
|
||||
4.4.1 Spinlocks
|
||||
|
||||
Most device drivers have a per-device spinlock which is taken in the
|
||||
interrupt handler. With pin-based interrupts or a single MSI, it is not
|
||||
|
|
@ -505,7 +190,7 @@ acquire the spinlock. Such deadlocks can be avoided by using
|
|||
spin_lock_irqsave() or spin_lock_irq() which disable local interrupts
|
||||
and acquire the lock (see Documentation/DocBook/kernel-locking).
|
||||
|
||||
4.6 How to tell whether MSI/MSI-X is enabled on a device
|
||||
4.5 How to tell whether MSI/MSI-X is enabled on a device
|
||||
|
||||
Using 'lspci -v' (as root) may show some devices with "MSI", "Message
|
||||
Signalled Interrupts" or "MSI-X" capabilities. Each of these capabilities
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
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