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, 78 insertions, 0 deletions

diff --git a/Documentation/fb/tridentfb.rst b/Documentation/fb/tridentfb.rst
new file mode 100644
index 000000000..7921c9dee
--- /dev/null
+++ b/Documentation/fb/tridentfb.rst
@@ -0,0 +1,78 @@
+=========
+Tridentfb
+=========
+
+Tridentfb is a framebuffer driver for some Trident chip based cards.
+
+The following list of chips is thought to be supported although not all are
+tested:
+
+those from the TGUI series 9440/96XX and with Cyber in their names
+those from the Image series and with Cyber in their names
+those with Blade in their names (Blade3D,CyberBlade...)
+the newer CyberBladeXP family
+
+All families are accelerated. Only PCI/AGP based cards are supported,
+none of the older Tridents.
+The driver supports 8, 16 and 32 bits per pixel depths.
+The TGUI family requires a line length to be power of 2 if acceleration
+is enabled. This means that range of possible resolutions and bpp is
+limited comparing to the range if acceleration is disabled (see list
+of parameters below).
+
+Known bugs:
+
+1. The driver randomly locks up on 3DImage975 chip with acceleration
+   enabled. The same happens in X11 (Xorg).
+2. The ramdac speeds require some more fine tuning. It is possible to
+   switch resolution which the chip does not support at some depths for
+   older chips.
+
+How to use it?
+==============
+
+When booting you can pass the video parameter::
+
+	video=tridentfb
+
+The parameters for tridentfb are concatenated with a ':' as in this example::
+
+	video=tridentfb:800x600-16@75,noaccel
+
+The second level parameters that tridentfb understands are:
+
+========  =====================================================================
+noaccel   turns off acceleration (when it doesn't work for your card)
+
+fp	  use flat panel related stuff
+crt 	  assume monitor is present instead of fp
+
+center 	  for flat panels and resolutions smaller than native size center the
+	  image, otherwise use
+stretch
+
+memsize   integer value in KB, use if your card's memory size is misdetected.
+	  look at the driver output to see what it says when initializing.
+
+memdiff   integer value in KB, should be nonzero if your card reports
+	  more memory than it actually has. For instance mine is 192K less than
+	  detection says in all three BIOS selectable situations 2M, 4M, 8M.
+	  Only use if your video memory is taken from main memory hence of
+	  configurable size. Otherwise use memsize.
+	  If in some modes which barely fit the memory you see garbage
+	  at the bottom this might help by not letting change to that mode
+	  anymore.
+
+nativex   the width in pixels of the flat panel.If you know it (usually 1024
+	  800 or 1280) and it is not what the driver seems to detect use it.
+
+bpp	  bits per pixel (8,16 or 32)
+mode	  a mode name like 800x600-8@75 as described in
+	  Documentation/fb/modedb.rst
+========  =====================================================================
+
+Using insane values for the above parameters will probably result in driver
+misbehaviour so take care(for instance memsize=12345678 or memdiff=23784 or
+nativex=93)
+
+Contact: jani@astechnix.ro