diff options
| author | Mike Loptien <loptienm@gmail.com> | 2014-05-12 21:46:31 -0600 |
|---|---|---|
| committer | Martin Roth <gaumless@gmail.com> | 2014-05-29 23:24:28 +0200 |
| commit | 0f5cf5e45b78d2e6a91d978bb86de5a4ff07c4d5 (patch) | |
| tree | 6d8719bec0d6a1bef9af8e228cc1087008e96356 /src/include | |
| parent | 433659ad1e864808ec30e90a62ecfd711559c5a9 (diff) | |
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>
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/device/pci.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/include/device/pci.h b/src/include/device/pci.h index 5594d293bd..81759706aa 100644 --- a/src/include/device/pci.h +++ b/src/include/device/pci.h @@ -82,6 +82,8 @@ void pci_dev_set_subsystem(device_t dev, unsigned vendor, unsigned device); void pci_dev_init(struct device *dev); unsigned int pci_match_simple_dev(device_t dev, pci_devfn_t sdev); +const char * pin_to_str(int pin); +int get_pci_irq_pins(device_t dev, device_t *parent_bdg); void pci_assign_irqs(unsigned bus, unsigned slot, const unsigned char pIntAtoD[4]); |