diff options
Diffstat (limited to 'Documentation/PCI')
| -rw-r--r-- | Documentation/PCI/MSI-HOWTO.txt | 6 | ||||
| -rw-r--r-- | Documentation/PCI/PCIEBUS-HOWTO.txt | 33 | ||||
| -rw-r--r-- | Documentation/PCI/pci-error-recovery.txt | 24 | ||||
| -rw-r--r-- | Documentation/PCI/pci.txt | 24 |
4 files changed, 24 insertions, 63 deletions
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index cd9c9f6a7cd9..1e37138027a3 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -162,8 +162,6 @@ The following old APIs to enable and disable MSI or MSI-X interrupts should not be used in new code: pci_enable_msi() /* deprecated */ - pci_enable_msi_range() /* deprecated */ - pci_enable_msi_exact() /* deprecated */ pci_disable_msi() /* deprecated */ pci_enable_msix_range() /* deprecated */ pci_enable_msix_exact() /* deprecated */ @@ -268,5 +266,5 @@ or disabled (0). If 0 is found in any of the msi_bus files belonging to bridges between the PCI root and the device, MSIs are disabled. It is also worth checking the device driver to see whether it supports MSIs. -For example, it may contain calls to pci_enable_msi_range() or -pci_enable_msix_range(). +For example, it may contain calls to pci_irq_alloc_vectors() with the +PCI_IRQ_MSI or PCI_IRQ_MSIX flags. diff --git a/Documentation/PCI/PCIEBUS-HOWTO.txt b/Documentation/PCI/PCIEBUS-HOWTO.txt index 6bd5f372adec..15f0bb3b5045 100644 --- a/Documentation/PCI/PCIEBUS-HOWTO.txt +++ b/Documentation/PCI/PCIEBUS-HOWTO.txt @@ -161,21 +161,13 @@ Since all service drivers of a PCI-PCI Bridge Port device are allowed to run simultaneously, below lists a few of possible resource conflicts with proposed solutions. -6.1 MSI Vector Resource - -The MSI capability structure enables a device software driver to call -pci_enable_msi to request MSI based interrupts. Once MSI interrupts -are enabled on a device, it stays in this mode until a device driver -calls pci_disable_msi to disable MSI interrupts and revert back to -INTx emulation mode. Since service drivers of the same PCI-PCI Bridge -port share the same physical device, if an individual service driver -calls pci_enable_msi/pci_disable_msi it may result unpredictable -behavior. For example, two service drivers run simultaneously on the -same physical Root Port. Both service drivers call pci_enable_msi to -request MSI based interrupts. A service driver may not know whether -any other service drivers have run on this Root Port. If either one -of them calls pci_disable_msi, it puts the other service driver -in a wrong interrupt mode. +6.1 MSI and MSI-X Vector Resource + +Once MSI or MSI-X interrupts are enabled on a device, it stays in this +mode until they are disabled again. Since service drivers of the same +PCI-PCI Bridge port share the same physical device, if an individual +service driver enables or disables MSI/MSI-X mode it may result +unpredictable behavior. To avoid this situation all service drivers are not permitted to switch interrupt mode on its device. The PCI Express Port Bus driver @@ -187,17 +179,6 @@ driver. Service drivers should use (struct pcie_device*)dev->irq to call request_irq/free_irq. In addition, the interrupt mode is stored in the field interrupt_mode of struct pcie_device. -6.2 MSI-X Vector Resources - -Similar to the MSI a device driver for an MSI-X capable device can -call pci_enable_msix to request MSI-X interrupts. All service drivers -are not permitted to switch interrupt mode on its device. The PCI -Express Port Bus driver is responsible for determining the interrupt -mode and this should be transparent to service drivers. Any attempt -by service driver to call pci_enable_msix/pci_disable_msix may -result unpredictable behavior. Service drivers should use -(struct pcie_device*)dev->irq and call request_irq/free_irq. - 6.3 PCI Memory/IO Mapped Regions Service drivers for PCI Express Power Management (PME), Advanced diff --git a/Documentation/PCI/pci-error-recovery.txt b/Documentation/PCI/pci-error-recovery.txt index ac26869c7db4..da3b2176d5da 100644 --- a/Documentation/PCI/pci-error-recovery.txt +++ b/Documentation/PCI/pci-error-recovery.txt @@ -78,7 +78,6 @@ struct pci_error_handlers { int (*error_detected)(struct pci_dev *dev, enum pci_channel_state); int (*mmio_enabled)(struct pci_dev *dev); - int (*link_reset)(struct pci_dev *dev); int (*slot_reset)(struct pci_dev *dev); void (*resume)(struct pci_dev *dev); }; @@ -104,8 +103,7 @@ if it implements any, it must implement error_detected(). If a callback is not implemented, the corresponding feature is considered unsupported. For example, if mmio_enabled() and resume() aren't there, then it is assumed that the driver is not doing any direct recovery and requires -a slot reset. If link_reset() is not implemented, the card is assumed to -not care about link resets. Typically a driver will want to know about +a slot reset. Typically a driver will want to know about a slot_reset(). The actual steps taken by a platform to recover from a PCI error @@ -232,25 +230,9 @@ proceeds to STEP 4 (Slot Reset) STEP 3: Link Reset ------------------ -The platform resets the link, and then calls the link_reset() callback -on all affected device drivers. This is a PCI-Express specific state +The platform resets the link. This is a PCI-Express specific step and is done whenever a non-fatal error has been detected that can be -"solved" by resetting the link. This call informs the driver of the -reset and the driver should check to see if the device appears to be -in working condition. - -The driver is not supposed to restart normal driver I/O operations -at this point. It should limit itself to "probing" the device to -check its recoverability status. If all is right, then the platform -will call resume() once all drivers have ack'd link_reset(). - - Result codes: - (identical to STEP 3 (MMIO Enabled) - -The platform then proceeds to either STEP 4 (Slot Reset) or STEP 5 -(Resume Operations). - ->>> The current powerpc implementation does not implement this callback. +"solved" by resetting the link. STEP 4: Slot Reset ------------------ diff --git a/Documentation/PCI/pci.txt b/Documentation/PCI/pci.txt index 77f49dc5be23..611a75e4366e 100644 --- a/Documentation/PCI/pci.txt +++ b/Documentation/PCI/pci.txt @@ -382,18 +382,18 @@ The fundamental difference between MSI and MSI-X is how multiple "vectors" get allocated. MSI requires contiguous blocks of vectors while MSI-X can allocate several individual ones. -MSI capability can be enabled by calling pci_enable_msi() or -pci_enable_msix() before calling request_irq(). This causes -the PCI support to program CPU vector data into the PCI device -capability registers. - -If your PCI device supports both, try to enable MSI-X first. -Only one can be enabled at a time. Many architectures, chip-sets, -or BIOSes do NOT support MSI or MSI-X and the call to pci_enable_msi/msix -will fail. This is important to note since many drivers have -two (or more) interrupt handlers: one for MSI/MSI-X and another for IRQs. -They choose which handler to register with request_irq() based on the -return value from pci_enable_msi/msix(). +MSI capability can be enabled by calling pci_alloc_irq_vectors() with the +PCI_IRQ_MSI and/or PCI_IRQ_MSIX flags before calling request_irq(). This +causes the PCI support to program CPU vector data into the PCI device +capability registers. Many architectures, chip-sets, or BIOSes do NOT +support MSI or MSI-X and a call to pci_alloc_irq_vectors with just +the PCI_IRQ_MSI and PCI_IRQ_MSIX flags will fail, so try to always +specify PCI_IRQ_LEGACY as well. + +Drivers that have different interrupt handlers for MSI/MSI-X and +legacy INTx should chose the right one based on the msi_enabled +and msix_enabled flags in the pci_dev structure after calling +pci_alloc_irq_vectors. There are (at least) two really good reasons for using MSI: 1) MSI is an exclusive interrupt vector by definition. |