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, 132 insertions, 0 deletions

diff --git a/Documentation/firmware-guide/acpi/debug.rst b/Documentation/firmware-guide/acpi/debug.rst
new file mode 100644
index 000000000..0639c9de0
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/debug.rst
@@ -0,0 +1,132 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================
+ACPI CA Debug Output
+====================
+
+The ACPI CA can generate debug output.  This document describes how to use this
+facility.
+
+Compile-time configuration
+==========================
+
+The ACPI CA debug output is globally enabled by CONFIG_ACPI_DEBUG.  If this
+config option is not set, the debug messages are not even built into the kernel.
+
+Boot- and run-time configuration
+================================
+
+When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages
+you're interested in.  At boot-time, use the acpi.debug_layer and
+acpi.debug_level kernel command line options.  After boot, you can use the
+debug_layer and debug_level files in /sys/module/acpi/parameters/ to control
+the debug messages.
+
+debug_layer (component)
+=======================
+
+The "debug_layer" is a mask that selects components of interest, e.g., a
+specific part of the ACPI interpreter.  To build the debug_layer bitmask, look
+for the "#define _COMPONENT" in an ACPI source file.
+
+You can set the debug_layer mask at boot-time using the acpi.debug_layer
+command line argument, and you can change it after boot by writing values
+to /sys/module/acpi/parameters/debug_layer.
+
+The possible components are defined in include/acpi/acoutput.h.
+
+Reading /sys/module/acpi/parameters/debug_layer shows the supported mask values::
+
+    ACPI_UTILITIES                  0x00000001
+    ACPI_HARDWARE                   0x00000002
+    ACPI_EVENTS                     0x00000004
+    ACPI_TABLES                     0x00000008
+    ACPI_NAMESPACE                  0x00000010
+    ACPI_PARSER                     0x00000020
+    ACPI_DISPATCHER                 0x00000040
+    ACPI_EXECUTER                   0x00000080
+    ACPI_RESOURCES                  0x00000100
+    ACPI_CA_DEBUGGER                0x00000200
+    ACPI_OS_SERVICES                0x00000400
+    ACPI_CA_DISASSEMBLER            0x00000800
+    ACPI_COMPILER                   0x00001000
+    ACPI_TOOLS                      0x00002000
+
+debug_level
+===========
+
+The "debug_level" is a mask that selects different types of messages, e.g.,
+those related to initialization, method execution, informational messages, etc.
+To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT()
+statement.
+
+The ACPI interpreter uses several different levels, but the Linux
+ACPI core and ACPI drivers generally only use ACPI_LV_INFO.
+
+You can set the debug_level mask at boot-time using the acpi.debug_level
+command line argument, and you can change it after boot by writing values
+to /sys/module/acpi/parameters/debug_level.
+
+The possible levels are defined in include/acpi/acoutput.h.  Reading
+/sys/module/acpi/parameters/debug_level shows the supported mask values,
+currently these::
+
+    ACPI_LV_INIT                    0x00000001
+    ACPI_LV_DEBUG_OBJECT            0x00000002
+    ACPI_LV_INFO                    0x00000004
+    ACPI_LV_INIT_NAMES              0x00000020
+    ACPI_LV_PARSE                   0x00000040
+    ACPI_LV_LOAD                    0x00000080
+    ACPI_LV_DISPATCH                0x00000100
+    ACPI_LV_EXEC                    0x00000200
+    ACPI_LV_NAMES                   0x00000400
+    ACPI_LV_OPREGION                0x00000800
+    ACPI_LV_BFIELD                  0x00001000
+    ACPI_LV_TABLES                  0x00002000
+    ACPI_LV_VALUES                  0x00004000
+    ACPI_LV_OBJECTS                 0x00008000
+    ACPI_LV_RESOURCES               0x00010000
+    ACPI_LV_USER_REQUESTS           0x00020000
+    ACPI_LV_PACKAGE                 0x00040000
+    ACPI_LV_ALLOCATIONS             0x00100000
+    ACPI_LV_FUNCTIONS               0x00200000
+    ACPI_LV_OPTIMIZATIONS           0x00400000
+    ACPI_LV_MUTEX                   0x01000000
+    ACPI_LV_THREADS                 0x02000000
+    ACPI_LV_IO                      0x04000000
+    ACPI_LV_INTERRUPTS              0x08000000
+    ACPI_LV_AML_DISASSEMBLE         0x10000000
+    ACPI_LV_VERBOSE_INFO            0x20000000
+    ACPI_LV_FULL_TABLES             0x40000000
+    ACPI_LV_EVENTS                  0x80000000
+
+Examples
+========
+
+For example, drivers/acpi/acpica/evxfevnt.c contains this::
+
+    #define _COMPONENT          ACPI_EVENTS
+    ...
+    ACPI_DEBUG_PRINT((ACPI_DB_INIT, "ACPI mode disabled\n"));
+
+To turn on this message, set the ACPI_EVENTS bit in acpi.debug_layer
+and the ACPI_LV_INIT bit in acpi.debug_level.  (The ACPI_DEBUG_PRINT
+statement uses ACPI_DB_INIT, which is a macro based on the ACPI_LV_INIT
+definition.)
+
+Enable all AML "Debug" output (stores to the Debug object while interpreting
+AML) during boot::
+
+    acpi.debug_layer=0xffffffff acpi.debug_level=0x2
+
+Enable all ACPI hardware-related messages::
+
+    acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
+
+Enable all ACPI_DB_INFO messages after boot::
+
+    # echo 0x4 > /sys/module/acpi/parameters/debug_level
+
+Show all valid component values::
+
+    # cat /sys/module/acpi/parameters/debug_layer