summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-19 19:07:27 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-19 19:07:27 -0800
commit5800700f66678ea5c85e7d62b138416070bf7f60 (patch)
tree4aeff1edb0429eb222ddea97701d1ab1efbca2d0 /Documentation
parent266d7ad7f4fe2f44b91561f5b812115c1b3018ab (diff)
parentaf8d102f999a41c0189bd2cce488bac2ee88c29b (diff)
Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/apic changes from Ingo Molnar: "Main changes: - Multiple MSI support added to the APIC, PCI and AHCI code - acked by all relevant maintainers, by Alexander Gordeev. The advantage is that multiple AHCI ports can have multiple MSI irqs assigned, and can thus spread to multiple CPUs. [ Drivers can make use of this new facility via the pci_enable_msi_block_auto() method ] - x86 IOAPIC code from interrupt remapping cleanups from Joerg Roedel: These patches move all interrupt remapping specific checks out of the x86 core code and replaces the respective call-sites with function pointers. As a result the interrupt remapping code is better abstraced from x86 core interrupt handling code. - Various smaller improvements, fixes and cleanups." * 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits) x86/intel/irq_remapping: Clean up x2apic opt-out security warning mess x86, kvm: Fix intialization warnings in kvm.c x86, irq: Move irq_remapped out of x86 core code x86, io_apic: Introduce eoi_ioapic_pin call-back x86, msi: Introduce x86_msi.compose_msi_msg call-back x86, irq: Introduce setup_remapped_irq() x86, irq: Move irq_remapped() check into free_remapped_irq x86, io-apic: Remove !irq_remapped() check from __target_IO_APIC_irq() x86, io-apic: Move CONFIG_IRQ_REMAP code out of x86 core x86, irq: Add data structure to keep AMD specific irq remapping information x86, irq: Move irq_remapping_enabled declaration to iommu code x86, io_apic: Remove irq_remapping_enabled check in setup_timer_IRQ0_pin x86, io_apic: Move irq_remapping_enabled checks out of check_timer() x86, io_apic: Convert setup_ioapic_entry to function pointer x86, io_apic: Introduce set_affinity function pointer x86, msi: Use IRQ remapping specific setup_msi_irqs routine x86, hpet: Introduce x86_msi_ops.setup_hpet_msi x86, io_apic: Introduce x86_io_apic_ops.print_entries for debugging x86, io_apic: Introduce x86_io_apic_ops.disable() x86, apic: Mask IO-APIC and PIC unconditionally on LAPIC resume ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/PCI/MSI-HOWTO.txt37
1 files changed, 32 insertions, 5 deletions
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index 53e6fca146d..a09178086c3 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -127,15 +127,42 @@ 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_disable_msi
+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.
+
+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
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(). 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() 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.
Before calling this function, a device driver must always call free_irq()
on any interrupt for which it previously called request_irq().