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For supporting post MSI-X enable allocations and for the upcoming PCI/IMS support a separate interface is required which allows not only the allocation of a specific index, but also the allocation of any, i.e. the next free index. The latter is especially required for IMS because IMS completely does away with index to functionality mappings which are often found in MSI/MSI-X implementation. But even with MSI-X there are devices where only the first few indices have a fixed functionality and the rest is freely assignable by software, e.g. to queues. msi_domain_alloc_irq_at() is also different from the range based interfaces as it always enforces that the MSI descriptor is allocated by the core code and not preallocated by the caller like the PCI/MSI[-X] enable code path does. msi_domain_alloc_irq_at() can be invoked with the index argument set to MSI_ANY_INDEX which makes the core code pick the next free index. The irq domain can provide a prepare_desc() operation callback in it's msi_domain_ops to do domain specific post allocation initialization before the actual Linux interrupt and the associated interrupt descriptor and hierarchy alloccations are conducted. The function also takes an optional @icookie argument which is of type union msi_instance_cookie. This cookie is not used by the core code and is stored in the allocated msi_desc::data::icookie. The meaning of the cookie is completely implementation defined. In case of IMS this might be a PASID or a pointer to a device queue, but for the MSI core it's opaque and not used in any way. The function returns a struct msi_map which on success contains the allocated index number and the Linux interrupt number so the caller can spare the index to Linux interrupt number lookup. On failure map::index contains the error code and map::virq is 0. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221124232326.501359457@linutronix.de |
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| .. | ||
| affinity.c | ||
| autoprobe.c | ||
| chip.c | ||
| cpuhotplug.c | ||
| debug.h | ||
| debugfs.c | ||
| devres.c | ||
| dummychip.c | ||
| generic-chip.c | ||
| handle.c | ||
| internals.h | ||
| ipi.c | ||
| irq_sim.c | ||
| irqdesc.c | ||
| irqdomain.c | ||
| Kconfig | ||
| Makefile | ||
| manage.c | ||
| matrix.c | ||
| migration.c | ||
| msi.c | ||
| pm.c | ||
| proc.c | ||
| resend.c | ||
| settings.h | ||
| spurious.c | ||
| timings.c | ||