John Baldwin 5fe82bca57 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		2007-01-22 21:48:44 +00:00
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pci_bus.c	Expand the MSI/MSI-X API to address some deficiencies in the MSI-X support.	2007-01-22 21:48:44 +00:00
pci_cfgreg.c