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, 107 insertions, 0 deletions

diff --git a/include/uapi/asm-generic/ioctl.h b/include/uapi/asm-generic/ioctl.h
new file mode 100644
index 000000000..e3290a582
--- /dev/null
+++ b/include/uapi/asm-generic/ioctl.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_ASM_GENERIC_IOCTL_H
+#define _UAPI_ASM_GENERIC_IOCTL_H
+
+/* ioctl command encoding: 32 bits total, command in lower 16 bits,
+ * size of the parameter structure in the lower 14 bits of the
+ * upper 16 bits.
+ * Encoding the size of the parameter structure in the ioctl request
+ * is useful for catching programs compiled with old versions
+ * and to avoid overwriting user space outside the user buffer area.
+ * The highest 2 bits are reserved for indicating the ``access mode''.
+ * NOTE: This limits the max parameter size to 16kB -1 !
+ */
+
+/*
+ * The following is for compatibility across the various Linux
+ * platforms.  The generic ioctl numbering scheme doesn't really enforce
+ * a type field.  De facto, however, the top 8 bits of the lower 16
+ * bits are indeed used as a type field, so we might just as well make
+ * this explicit here.  Please be sure to use the decoding macros
+ * below from now on.
+ */
+#define _IOC_NRBITS	8
+#define _IOC_TYPEBITS	8
+
+/*
+ * Let any architecture override either of the following before
+ * including this file.
+ */
+
+#ifndef _IOC_SIZEBITS
+# define _IOC_SIZEBITS	14
+#endif
+
+#ifndef _IOC_DIRBITS
+# define _IOC_DIRBITS	2
+#endif
+
+#define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
+#define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
+#define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
+#define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
+
+#define _IOC_NRSHIFT	0
+#define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
+#define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
+#define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
+
+/*
+ * Direction bits, which any architecture can choose to override
+ * before including this file.
+ *
+ * NOTE: _IOC_WRITE means userland is writing and kernel is
+ * reading. _IOC_READ means userland is reading and kernel is writing.
+ */
+
+#ifndef _IOC_NONE
+# define _IOC_NONE	0U
+#endif
+
+#ifndef _IOC_WRITE
+# define _IOC_WRITE	1U
+#endif
+
+#ifndef _IOC_READ
+# define _IOC_READ	2U
+#endif
+
+#define _IOC(dir,type,nr,size) \
+	(((dir)  << _IOC_DIRSHIFT) | \
+	 ((type) << _IOC_TYPESHIFT) | \
+	 ((nr)   << _IOC_NRSHIFT) | \
+	 ((size) << _IOC_SIZESHIFT))
+
+#ifndef __KERNEL__
+#define _IOC_TYPECHECK(t) (sizeof(t))
+#endif
+
+/*
+ * Used to create numbers.
+ *
+ * NOTE: _IOW means userland is writing and kernel is reading. _IOR
+ * means userland is reading and kernel is writing.
+ */
+#define _IO(type,nr)			_IOC(_IOC_NONE,(type),(nr),0)
+#define _IOR(type,nr,argtype)		_IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(argtype)))
+#define _IOW(type,nr,argtype)		_IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(argtype)))
+#define _IOWR(type,nr,argtype)		_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(argtype)))
+#define _IOR_BAD(type,nr,argtype)	_IOC(_IOC_READ,(type),(nr),sizeof(argtype))
+#define _IOW_BAD(type,nr,argtype)	_IOC(_IOC_WRITE,(type),(nr),sizeof(argtype))
+#define _IOWR_BAD(type,nr,argtype)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(argtype))
+
+/* used to decode ioctl numbers.. */
+#define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
+#define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
+#define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
+#define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
+
+/* ...and for the drivers/sound files... */
+
+#define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
+#define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
+#define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
+#define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
+#define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
+
+#endif /* _UAPI_ASM_GENERIC_IOCTL_H */