the following patch was just integrated into master: commit 0f5cf5e45b78d2e6a91d978bb86de5a4ff07c4d5 Author: Mike Loptien loptienm@gmail.com Date: Mon May 12 21:46:31 2014 -0600
PCI IRQs: Swizzle PCI IRQs for PCI bridges
The PCI Specification states that devices that implement a bridge and a secondary bus must swizzle (rotate) the interrupt pins according to the table below: Child Dev # Child PIN Parent PIN 0,4,8,12... A/B/C/D A/B/C/D 1,5,9,13... A/B/C/D B/C/D/A 2,6,10,14.. A/B/C/D C/D/A/B 3,7,11,15.. A/B/C/D D/A/B/C
Which is also described by this equation: PIN_parent = (Pin_child + Dev_child) % 4
When a device is found and its bus number is greater than 0, it is on a bridge and needs to be swizzled. Following the string of parents up to the root bus and swizzling as we go gives us the desired swizzling result. When BIOS_SPEW is defined, it will print out each step of the swizzling process.
Change-Id: Icafeadd01983282c86e25f560c831c9482c74e68 Signed-off-by: Martin Roth gaumless@gmail.com Reviewed-on: http://review.coreboot.org/5734 Tested-by: build bot (Jenkins) Reviewed-by: Marc Jones marc.jones@se-eng.com Reviewed-by: Mike Loptien mike.loptien@se-eng.com
See http://review.coreboot.org/5734 for details.
-gerrit