sandy/ivy/nehalem: Remerge interrupt handling

On those chipsets the pins are just a legacy concept. Real interrupts are
messages on corresponding busses or some internal logic of chipset.
Hence interrupt routing isn't anymore board-specific (dependent on layout) but
depends only on configuration.
Rather than attempting to sync real config, ACPI and legacy descriptors, just
use the same interrupt routing per chipset covering all possible devices.

The only part which remains board-specific are LPC and PCI interrupts.

Interrupt balancing may suffer from such merge but:
a) Doesn't seem to be the case of this map on current systems
b) Almost all OS use MSI nowadays bypassing this stuff completely
c) If we want a good balancing we need to take into account that e.g.
   wlan card may be placed in a different slot and so would require complicated
   balancing on runtime. It's difficult to maintain with almost no benefit.

Change-Id: I9f63d1d338c5587ebac7a52093e5b924f6e5ca2d
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7130
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

1 files changed, 19 insertions, 24 deletions

diff --git a/src/southbridge/intel/ibexpeak/lpc.c b/src/southbridge/intel/ibexpeak/lpc.c
index 03b40495e1..212471136d 100644
--- a/src/southbridge/intel/ibexpeak/lpc.c
+++ b/src/southbridge/intel/ibexpeak/lpc.c
@@ -106,42 +106,37 @@ static void pch_enable_serial_irqs(struct device *dev)
 static void pch_pirq_init(device_t dev)
 {
 	device_t irq_dev;
-	/* Get the chip configuration */
-	config_t *config = dev->chip_info;
-
-	pci_write_config8(dev, PIRQA_ROUT, config->pirqa_routing);
-	pci_write_config8(dev, PIRQB_ROUT, config->pirqb_routing);
-	pci_write_config8(dev, PIRQC_ROUT, config->pirqc_routing);
-	pci_write_config8(dev, PIRQD_ROUT, config->pirqd_routing);
+	/* Interrupt 11 is not used by legacy devices and so can always be used for
+	   PCI interrupts. Full legacy IRQ routing is complicated and hard to
+	   get right. Fortunately all modern OS use MSI and so it's not that big of
+	   an issue anyway. Still we have to provide a reasonable default. Using
+	   interrupt 11 for it everywhere is a working default. ACPI-aware OS can
+	   move it to any interrupt and others will just leave them at default.
+	 */
+	const u8 pirq_routing = 11;
 
-	pci_write_config8(dev, PIRQE_ROUT, config->pirqe_routing);
-	pci_write_config8(dev, PIRQF_ROUT, config->pirqf_routing);
-	pci_write_config8(dev, PIRQG_ROUT, config->pirqg_routing);
-	pci_write_config8(dev, PIRQH_ROUT, config->pirqh_routing);
+	pci_write_config8(dev, PIRQA_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQB_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQC_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQD_ROUT, pirq_routing);
 
-	/* Eric Biederman once said we should let the OS do this.
-	 * I am not so sure anymore he was right.
-	 */
+	pci_write_config8(dev, PIRQE_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQF_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQG_ROUT, pirq_routing);
+	pci_write_config8(dev, PIRQH_ROUT, pirq_routing);
 
 	for(irq_dev = all_devices; irq_dev; irq_dev = irq_dev->next) {
-		u8 int_pin=0, int_line=0;
+		u8 int_pin=0;
 
 		if (!irq_dev->enabled || irq_dev->path.type != DEVICE_PATH_PCI)
 			continue;
 
 		int_pin = pci_read_config8(irq_dev, PCI_INTERRUPT_PIN);
 
-		switch (int_pin) {
-		case 1: /* INTA# */ int_line = config->pirqa_routing; break;
-		case 2: /* INTB# */ int_line = config->pirqb_routing; break;
-		case 3: /* INTC# */ int_line = config->pirqc_routing; break;
-		case 4: /* INTD# */ int_line = config->pirqd_routing; break;
-		}
-
-		if (!int_line)
+		if (int_pin == 0)
 			continue;
 
-		pci_write_config8(irq_dev, PCI_INTERRUPT_LINE, int_line);
+		pci_write_config8(irq_dev, PCI_INTERRUPT_LINE, pirq_routing);
 	}
 }