[PULL 25/46] hw/mips/malta: Set PIIX4 IRQ routes in embedded bootloader

[Philippe Mathieu-Daudé]

Linux kernel expects the northbridge & southbridge chipsets
configured by the BIOS firmware. We emulate that by writing
a tiny bootloader code in write_bootloader().

Upon introduction in commit 5c2b87e34d ("PIIX4 support"),
the PIIX4 configuration space included values specific to
the Malta board.

Set the Malta-specific IRQ routing values in the embedded
bootloader, so the next commit can remove the Malta specific
bits from the PIIX4 PCI-ISA bridge and make it generic
(matching the real hardware).

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221027204720.33611-3-philmd@linaro.org>
---
 hw/mips/malta.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/hw/mips/malta.c b/hw/mips/malta.c
index 9fc3280407..ae76b4db70 100644
--- a/hw/mips/malta.c
+++ b/hw/mips/malta.c
@@ -621,6 +621,10 @@ static void network_init(PCIBus *pci_bus)
 static void bl_setup_gt64120_jump_kernel(void **p, uint64_t run_addr,
                                          uint64_t kernel_entry)
 {
+    static const char pci_pins_cfg[PCI_NUM_PINS] = {
+        10, 10, 11, 11 /* PIIX IRQRC[A:D] */
+    };
+
     /* Bus endianess is always reversed */
 #if TARGET_BIG_ENDIAN
 #define cpu_to_gt32 cpu_to_le32
@@ -659,6 +663,20 @@ static void bl_setup_gt64120_jump_kernel(void **p, 
uint64_t run_addr,
 
 #undef cpu_to_gt32
 
+    /*
+     * The PIIX ISA bridge is on PCI bus 0 dev 10 func 0.
+     * Load the PIIX IRQC[A:D] routing config address, then
+     * write routing configuration to the config data register.
+     */
+    bl_gen_write_u32(p, /* GT_PCI0_CFGADDR */
+                     cpu_mips_phys_to_kseg1(NULL, 0x1be00000 + 0xcf8),
+                     tswap32((1 << 31) /* ConfigEn */
+                             | PCI_BUILD_BDF(0, PIIX4_PCI_DEVFN) << 8
+                             | PIIX_PIRQCA));
+    bl_gen_write_u32(p, /* GT_PCI0_CFGDATA */
+                     cpu_mips_phys_to_kseg1(NULL, 0x1be00000 + 0xcfc),
+                     tswap32(ldl_be_p(pci_pins_cfg)));
+
     bl_gen_jump_kernel(p,
                        true, ENVP_VADDR - 64,
                        /*
-- 
2.38.1