mac_oldworld: Allow loading binary ROM image

The beige G3 Power Macintosh has a 4MB firmware ROM. Fix the size of
the rom region and fall back to loading a binary image with -bios if
loading ELF image failed. This allows testing emulation with a ROM
image from real hardware as well as using an ELF OpenBIOS image.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20201017155139.5A36A746331@zero.eik.bme.hu>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

hw/ppc/mac_oldworld.c

@@ -59,6 +59,8 @@
 #define NDRV_VGA_FILENAME "qemu_vga.ndrv"
 
 #define GRACKLE_BASE 0xfec00000
+#define PROM_BASE 0xffc00000
+#define PROM_SIZE (4 * MiB)
 
 static void fw_cfg_boot_set(void *opaque, const char *boot_device,
                             Error **errp)
@@ -100,6 +102,7 @@ static void ppc_heathrow_init(MachineState *machine)
     SysBusDevice *s;
     DeviceState *dev, *pic_dev;
     BusState *adb_bus;
+    uint64_t bios_addr;
     int bios_size;
     unsigned int smp_cpus = machine->smp.cpus;
     uint16_t ppc_boot_device;
@@ -128,24 +131,32 @@ static void ppc_heathrow_init(MachineState *machine)
 
     memory_region_add_subregion(sysmem, 0, machine->ram);
 
-    /* allocate and load BIOS */
-    memory_region_init_rom(bios, NULL, "ppc_heathrow.bios", BIOS_SIZE,
+    /* allocate and load firmware ROM */
+    memory_region_init_rom(bios, NULL, "ppc_heathrow.bios", PROM_SIZE,
                            &error_fatal);
+    memory_region_add_subregion(sysmem, PROM_BASE, bios);
 
-    if (bios_name == NULL)
+    if (!bios_name) {
         bios_name = PROM_FILENAME;
+    }
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
-    memory_region_add_subregion(sysmem, PROM_ADDR, bios);
-
-    /* Load OpenBIOS (ELF) */
     if (filename) {
-        bios_size = load_elf(filename, NULL, 0, NULL, NULL, NULL, NULL, NULL,
-                             1, PPC_ELF_MACHINE, 0, 0);
+        /* Load OpenBIOS (ELF) */
+        bios_size = load_elf(filename, NULL, NULL, NULL, NULL, &bios_addr,
+                             NULL, NULL, 1, PPC_ELF_MACHINE, 0, 0);
+        /* Unfortunately, load_elf sign-extends reading elf32 */
+        bios_addr = (uint32_t)bios_addr;
+
+        if (bios_size <= 0) {
+            /* or load binary ROM image */
+            bios_size = load_image_targphys(filename, PROM_BASE, PROM_SIZE);
+            bios_addr = PROM_BASE;
+        }
         g_free(filename);
     } else {
         bios_size = -1;
     }
-    if (bios_size < 0 || bios_size > BIOS_SIZE) {
+    if (bios_size < 0 || bios_addr - PROM_BASE + bios_size > PROM_SIZE) {
         error_report("could not load PowerPC bios '%s'", bios_name);
         exit(1);
     }