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author | jhb <jhb@FreeBSD.org> | 2007-01-22 21:48:44 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2007-01-22 21:48:44 +0000 |
commit | 3624354c54eb965482e4bb6a2769c0feb7248692 (patch) | |
tree | e54f3042911f50266b958edf09a9fe2525a0987a /sys/dev/pci/pci_if.m | |
parent | 4a22f82e6c50a7bc72683c16a7b8ea6a6d5624e4 (diff) | |
download | FreeBSD-src-3624354c54eb965482e4bb6a2769c0feb7248692.zip FreeBSD-src-3624354c54eb965482e4bb6a2769c0feb7248692.tar.gz |
Expand the MSI/MSI-X API to address some deficiencies in the MSI-X support.
- First off, device drivers really do need to know if they are allocating
MSI or MSI-X messages. MSI requires allocating powerof2() messages for
example where MSI-X does not. To address this, split out the MSI-X
support from pci_msi_count() and pci_alloc_msi() into new driver-visible
functions pci_msix_count() and pci_alloc_msix(). As a result,
pci_msi_count() now just returns a count of the max supported MSI
messages for the device, and pci_alloc_msi() only tries to allocate MSI
messages. To get a count of the max supported MSI-X messages, use
pci_msix_count(). To allocate MSI-X messages, use pci_alloc_msix().
pci_release_msi() still handles both MSI and MSI-X messages, however.
As a result of this change, drivers using the existing API will only
use MSI messages and will no longer try to use MSI-X messages.
- Because MSI-X allows for each message to have its own data and address
values (and thus does not require all of the messages to have their
MD vectors allocated as a group), some devices allow for "sparse" use
of MSI-X message slots. For example, if a device supports 8 messages
but the OS is only able to allocate 2 messages, the device may make the
best use of 2 IRQs if it enables the messages at slots 1 and 4 rather
than default of using the first N slots (or indicies) at 1 and 2. To
support this, add a new pci_remap_msix() function that a driver may call
after a successful pci_alloc_msix() (but before allocating any of the
SYS_RES_IRQ resources) to allow the allocated IRQ resources to be
assigned to different message indices. For example, from the earlier
example, after pci_alloc_msix() returned a value of 2, the driver would
call pci_remap_msix() passing in array of integers { 1, 4 } as the
new message indices to use. The rid's for the SYS_RES_IRQ resources
will always match the message indices. Thus, after the call to
pci_remap_msix() the driver would be able to access the first message
in slot 1 at SYS_RES_IRQ rid 1, and the second message at slot 4 at
SYS_RES_IRQ rid 4. Note that the message slots/indices are 1-based
rather than 0-based so that they will always correspond to the rid
values (SYS_RES_IRQ rid 0 is reserved for the legacy INTx interrupt).
To support this API, a new PCIB_REMAP_MSIX() method was added to the
pcib interface to change the message index for a single IRQ.
Tested by: scottl
Diffstat (limited to 'sys/dev/pci/pci_if.m')
-rw-r--r-- | sys/dev/pci/pci_if.m | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/sys/dev/pci/pci_if.m b/sys/dev/pci/pci_if.m index ba60415..266ec34 100644 --- a/sys/dev/pci/pci_if.m +++ b/sys/dev/pci/pci_if.m @@ -118,6 +118,18 @@ METHOD int alloc_msi { int *count; }; +METHOD int alloc_msix { + device_t dev; + device_t child; + int *count; +}; + +METHOD int remap_msix { + device_t dev; + device_t child; + u_int *indices; +}; + METHOD int release_msi { device_t dev; device_t child; @@ -127,3 +139,8 @@ METHOD int msi_count { device_t dev; device_t child; } DEFAULT null_msi_count; + +METHOD int msix_count { + device_t dev; + device_t child; +} DEFAULT null_msi_count; |