malta: setup PIIX4 interrupt route

Without setting up the PIRQ[A:D] interrupt routes, PCI interrupts will
be left disabled. Linux does not set up this routing but relies upon it
having been set up by the bootloader, reading back the IRQ lines which
the PIRQ[A:D] signals have been routed to.

This patch routes PIRQA & PIRQB to IRQ 10, and PIRQC & PIRQD to IRQ 11.
This matches the setup used by YAMON.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

arch/mips/include/asm/malta.h

@@ -53,4 +53,9 @@
 #define MALTA_REVISION_CORID_CORE_LV		1
 #define MALTA_REVISION_CORID_CORE_FPGA6		14
 
+#define PCI_CFG_PIIX4_PIRQRCA		0x60
+#define PCI_CFG_PIIX4_PIRQRCB		0x61
+#define PCI_CFG_PIIX4_PIRQRCC		0x62
+#define PCI_CFG_PIIX4_PIRQRCD		0x63
+
 #endif /* _MIPS_ASM_MALTA_H */

board/imgtec/malta/malta.c

@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <netdev.h>
+#include <pci.h>
 #include <pci_gt64120.h>
 #include <pci_msc01.h>
 #include <rtc.h>
@@ -169,6 +170,8 @@ struct serial_device *default_serial_console(void)
 
 void pci_init_board(void)
 {
+	pci_dev_t bdf;
+
 	switch (malta_sys_con()) {
 	case SYSCON_GT64120:
 		set_io_port_base(CKSEG1ADDR(MALTA_GT_PCIIO_BASE));
@@ -191,4 +194,15 @@ void pci_init_board(void)
 			       0x00000000, MALTA_MSC01_PCIIO_SIZE);
 		break;
 	}
+
+	bdf = pci_find_device(PCI_VENDOR_ID_INTEL,
+			      PCI_DEVICE_ID_INTEL_82371AB_0, 0);
+	if (bdf == -1)
+		panic("Failed to find PIIX4 PCI bridge\n");
+
+	/* setup PCI interrupt routing */
+	pci_write_config_byte(bdf, PCI_CFG_PIIX4_PIRQRCA, 10);
+	pci_write_config_byte(bdf, PCI_CFG_PIIX4_PIRQRCB, 10);
+	pci_write_config_byte(bdf, PCI_CFG_PIIX4_PIRQRCC, 11);
+	pci_write_config_byte(bdf, PCI_CFG_PIIX4_PIRQRCD, 11);
 }