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authorMike Loptien <loptienm@gmail.com>2014-05-12 21:46:31 -0600
committerMartin Roth <gaumless@gmail.com>2014-05-29 23:24:28 +0200
commit0f5cf5e45b78d2e6a91d978bb86de5a4ff07c4d5 (patch)
tree6d8719bec0d6a1bef9af8e228cc1087008e96356 /src/include/device
parent433659ad1e864808ec30e90a62ecfd711559c5a9 (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/device')
-rw-r--r--src/include/device/pci.h2
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]);