prep: add support for OpenBIOS

index dfe4a5c..e59d5b9 100644
@@ -52,6 +52,8 @@
 
 #define MAX_IDE_BUS 2
 
+#define CFG_ADDR 0xf0000510
+
 #define BIOS_SIZE (1024 * 1024)
 #define BIOS_FILENAME "ppc_rom.bin"
 #define KERNEL_LOAD_ADDR 0x01000000

@@ -358,6 +360,12 @@ static const MemoryRegionPortio prep_portio_list[] = {
     PORTIO_END_OF_LIST(),
 };
 
+static int fw_cfg_boot_set(void *opaque, const char *boot_device)
+{
+    fw_cfg_add_i16(opaque, FW_CFG_BOOT_DEVICE, boot_device[0]);
+    return 0;
+}
+
 /* PowerPC PREP hardware initialisation */
 static void ppc_prep_init(QEMUMachineInitArgs *args)
 {

@@ -389,6 +397,7 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
     qemu_irq *cpu_exit_irq;
     int ppc_boot_device;
     DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
+    void *fw_cfg;
 
     sysctrl = g_malloc0(sizeof(sysctrl_t));
 

@@ -559,6 +568,39 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
                          /* XXX: need an option to load a NVRAM image */
                          0,
                          graphic_width, graphic_height, graphic_depth);
+
+    /* Prepare firmware configuration for OpenBIOS */
+    fw_cfg = fw_cfg_init(0, 0, CFG_ADDR, CFG_ADDR + 2);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, (uint16_t)max_cpus);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);
+    fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)args->ram_size);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_MACHINE_ID, ARCH_PREP);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, 0);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, 0);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_CMDLINE, 0);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, 0);
+    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, 0);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_BOOT_DEVICE, boot_device[0]);
+
+    fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_WIDTH, graphic_width);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_HEIGHT, graphic_height);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_PPC_DEPTH, graphic_depth);
+
+    fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_IS_KVM, kvm_enabled());
+    if (kvm_enabled()) {
+#ifdef CONFIG_KVM
+        uint8_t *hypercall;
+
+        fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, kvmppc_get_tbfreq());
+        hypercall = g_malloc(16);
+        kvmppc_get_hypercall(env, hypercall, 16);
+        fw_cfg_add_bytes(fw_cfg, FW_CFG_PPC_KVM_HC, hypercall, 16);
+        fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_KVM_PID, getpid());
+#endif
+    } else {
+        fw_cfg_add_i32(fw_cfg, FW_CFG_PPC_TBFREQ, get_ticks_per_sec());
+    }
+    qemu_register_boot_set(fw_cfg_boot_set, fw_cfg);
 }
 
 static QEMUMachine prep_machine = {