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109 files changed, 2510 insertions, 1985 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 5210a51c90fd..a3c5a6685036 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -70,18 +70,15 @@ Date: September, 2011 Contact: Neil Horman <nhorman@tuxdriver.com> Description: The /sys/devices/.../msi_irqs directory contains a variable set - of sub-directories, with each sub-directory being named after a - corresponding msi irq vector allocated to that device. Each - numbered sub-directory N contains attributes of that irq. - Note that this directory is not created for device drivers which - do not support msi irqs + of files, with each file being named after a corresponding msi + irq vector allocated to that device. -What: /sys/bus/pci/devices/.../msi_irqs/<N>/mode +What: /sys/bus/pci/devices/.../msi_irqs/<N> Date: September 2011 Contact: Neil Horman <nhorman@tuxdriver.com> Description: This attribute indicates the mode that the irq vector named by - the parent directory is in (msi vs. msix) + the file is in (msi vs. msix) What: /sys/bus/pci/devices/.../remove Date: January 2009 diff --git a/Documentation/PCI/00-INDEX b/Documentation/PCI/00-INDEX index 812b17fe3ed0..147231f1613e 100644 --- a/Documentation/PCI/00-INDEX +++ b/Documentation/PCI/00-INDEX @@ -2,12 +2,12 @@ - this file MSI-HOWTO.txt - the Message Signaled Interrupts (MSI) Driver Guide HOWTO and FAQ. -PCI-DMA-mapping.txt - - info for PCI drivers using DMA portably across all platforms PCIEBUS-HOWTO.txt - a guide describing the PCI Express Port Bus driver pci-error-recovery.txt - info on PCI error recovery +pci-iov-howto.txt + - the PCI Express I/O Virtualization HOWTO pci.txt - info on the PCI subsystem for device driver authors pcieaer-howto.txt diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index a09178086c30..a8d01005f480 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -82,93 +82,111 @@ Most of the hard work is done for the driver in the PCI layer. It simply has to request that the PCI layer set up the MSI capability for this device. -4.2.1 pci_enable_msi +4.2.1 pci_enable_msi_range -int pci_enable_msi(struct pci_dev *dev) +int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec) -A successful call allocates ONE interrupt to the device, regardless -of how many MSIs the device supports. The device is switched from -pin-based interrupt mode to MSI mode. The dev->irq number is changed -to a new number which represents the message signaled interrupt; -consequently, this function should be called before the driver calls -request_irq(), because an MSI is delivered via a vector that is -different from the vector of a pin-based interrupt. +This function allows a device driver to request any number of MSI +interrupts within specified range from 'minvec' to 'maxvec'. -4.2.2 pci_enable_msi_block +If this function returns a positive number it indicates the number of +MSI interrupts that have been successfully allocated. In this case +the device is switched from pin-based interrupt mode to MSI mode 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. Device driver can use the returned +number of successfully allocated MSI interrupts to further allocate +and initialize device resources. -int pci_enable_msi_block(struct pci_dev *dev, int count) +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. -This variation on the above call allows a device driver to request multiple -MSIs. The MSI specification only allows interrupts to be allocated in -powers of two, up to a maximum of 2^5 (32). +This function should be called before the driver calls request_irq(), +because MSI interrupts are delivered via vectors that are different +from the vector of a pin-based interrupt. -If this function returns 0, it has succeeded in allocating at least as many -interrupts as the driver requested (it may have allocated more in order -to satisfy the power-of-two requirement). 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 + count - 1. +It is ideal if drivers can cope with a variable number of MSI interrupts; +there are many reasons why the platform may not be able to provide the +exact number that a driver asks for. -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 this function returns a positive number, it is -less than 'count' and indicates the number of interrupts that could have -been allocated. In neither case is the irq value updated or the device -switched into MSI mode. - -The device driver must decide what action to take if -pci_enable_msi_block() returns a value less than the number requested. -For instance, the driver could still make use of fewer interrupts; -in this case the driver should call pci_enable_msi_block() -again. Note that it is not guaranteed to succeed, even when the -'count' has been reduced to the value returned from a previous call to -pci_enable_msi_block(). This is because there are multiple constraints -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, unsigned 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. +There could be devices that can not operate with just any number of MSI +interrupts within a range. See chapter 4.3.1.3 to get the idea how to +handle such devices for MSI-X - the same logic applies to MSI. -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. +4.2.1.1 Maximum possible number of MSI interrupts + +The typical usage of MSI interrupts is to allocate as many vectors as +possible, likely up to the limit returned by pci_msi_vec_count() function: + +static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec) +{ + return pci_enable_msi_range(pdev, 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. -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. +Some devices have a minimal limit on number of MSI interrupts. +In this case the function could look like this: -4.2.4 pci_disable_msi +static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec) +{ + return pci_enable_msi_range(pdev, FOO_DRIVER_MINIMUM_NVEC, nvec); +} + +4.2.1.2 Exact number of MSI interrupts + +If a driver is unable or unwilling to deal with a variable number of MSI +interrupts it could request a particular number of interrupts by passing +that number to pci_enable_msi_range() function as both 'minvec' and 'maxvec' +parameters: + +static int foo_driver_enable_msi(struct pci_dev *pdev, int nvec) +{ + return pci_enable_msi_range(pdev, nvec, nvec); +} + +4.2.1.3 Single MSI mode + +The most notorious example of the request type described above is +enabling the single MSI mode for a device. It could be done by passing +two 1s as 'minvec' and 'maxvec': + +static int foo_driver_enable_single_msi(struct pci_dev *pdev) +{ + return pci_enable_msi_range(pdev, 1, 1); +} + +4.2.2 pci_disable_msi void pci_disable_msi(struct pci_dev *dev) -This function sho |