PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 103 insertions, 0 deletions

diff --git a/Documentation/edac/features.rst b/Documentation/edac/features.rst
new file mode 100644
index 000000000..3f283de29
--- /dev/null
+++ b/Documentation/edac/features.rst
@@ -0,0 +1,103 @@
+.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.2-no-invariants-or-later
+
+=================
+EDAC/RAS features
+=================
+
+Copyright (c) 2024-2025 HiSilicon Limited.
+
+:Author:   Shiju Jose <shiju.jose@huawei.com>
+:License:  The GNU Free Documentation License, Version 1.2 without
+           Invariant Sections, Front-Cover Texts nor Back-Cover Texts.
+           (dual licensed under the GPL v2)
+
+- Written for: 6.15
+
+Introduction
+------------
+
+EDAC/RAS components plugging and high-level design:
+
+1. Scrub control
+
+2. Error Check Scrub (ECS) control
+
+3. ACPI RAS2 features
+
+4. Post Package Repair (PPR) control
+
+5. Memory Sparing Repair control
+
+High level design is illustrated in the following diagram::
+
+        +-----------------------------------------------+
+        |   Userspace - Rasdaemon                       |
+        | +-------------+                               |
+        | | RAS CXL mem |     +---------------+         |
+        | |error handler|---->|               |         |
+        | +-------------+     | RAS dynamic   |         |
+        | +-------------+     | scrub, memory |         |
+        | | RAS memory  |---->| repair control|         |
+        | |error handler|     +----|----------+         |
+        | +-------------+          |                    |
+        +--------------------------|--------------------+
+                                   |
+                                   |
+   +-------------------------------|------------------------------+
+   |     Kernel EDAC extension for | controlling RAS Features     |
+   |+------------------------------|----------------------------+ |
+   || EDAC Core          Sysfs EDAC| Bus                        | |
+   ||   +--------------------------|---------------------------+| |
+   ||   |/sys/bus/edac/devices/<dev>/scrubX/ |   | EDAC device || |
+   ||   |/sys/bus/edac/devices/<dev>/ecsX/   |<->| EDAC MC     || |
+   ||   |/sys/bus/edac/devices/<dev>/repairX |   | EDAC sysfs  || |
+   ||   +---------------------------|--------------------------+| |
+   ||                           EDAC|Bus                        | |
+   ||                               |                           | |
+   ||   +----------+ Get feature    |      Get feature          | |
+   ||   |          | desc +---------|------+ desc +----------+  | |
+   ||   |EDAC scrub|<-----| EDAC device    |      |          |  | |
+   ||   +----------+      | driver- RAS    |----->| EDAC mem |  | |
+   ||   +----------+      | feature control|      | repair   |  | |
+   ||   |          |<-----|                |      +----------+  | |
+   ||   |EDAC ECS  |      +---------|------+                    | |
+   ||   +----------+    Register RAS|features                   | |
+   ||         ______________________|_____________              | |
+   |+---------|---------------|------------------|--------------+ |
+   |  +-------|----+  +-------|-------+     +----|----------+     |
+   |  |            |  | CXL mem driver|     | Client driver |     |
+   |  | ACPI RAS2  |  | scrub, ECS,   |     | memory repair |     |
+   |  | driver     |  | sparing, PPR  |     | features      |     |
+   |  +-----|------+  +-------|-------+     +------|--------+     |
+   |        |                 |                    |              |
+   +--------|-----------------|--------------------|--------------+
+            |                 |                    |
+   +--------|-----------------|--------------------|--------------+
+   |    +---|-----------------|--------------------|-------+      |
+   |    |                                                  |      |
+   |    |            Platform HW and Firmware              |      |
+   |    +--------------------------------------------------+      |
+   +--------------------------------------------------------------+
+
+
+1. EDAC Features components - Create feature-specific descriptors. For
+   example: scrub, ECS, memory repair in the above diagram.
+
+2. EDAC device driver for controlling RAS Features - Get feature's attribute
+   descriptors from EDAC RAS feature component and registers device's RAS
+   features with EDAC bus and expose the features control attributes via
+   sysfs. For example, /sys/bus/edac/devices/<dev-name>/<feature>X/
+
+3. RAS dynamic feature controller - Userspace sample modules in rasdaemon for
+   dynamic scrub/repair control to issue scrubbing/repair when excess number
+   of corrected memory errors are reported in a short span of time.
+
+RAS features
+------------
+1. Memory Scrub
+
+Memory scrub features are documented in `Documentation/edac/scrub.rst`.
+
+2. Memory Repair
+
+Memory repair features are documented in `Documentation/edac/memory_repair.rst`.