hw/arm/vexpress: Add alias for flash at address 0 on A15 board

The A15 Versatile Express board can remap a variety of things at address
0. We don't currently emulate the Serial Configuration Controller which
is how the guest can control this remapping, but we can provide the
initial default mapping of the first flash device into this space.
In particular this allows QEMU to boot flash images such as UEFI which
expect to include an exception vector table.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Tested-by: NGrant Likely <grant.likely@linaro.org>
Message-id: 1373374180-19884-1-git-send-email-peter.maydell@linaro.org

hw/arm/vexpress.c

@@ -67,6 +67,7 @@ enum {
     VE_CLCD,
     VE_NORFLASH0,
     VE_NORFLASH1,
+    VE_NORFLASHALIAS,
     VE_SRAM,
     VE_VIDEORAM,
     VE_ETHERNET,
@@ -104,9 +105,11 @@ static hwaddr motherboard_legacy_map[] = {
     [VE_VIDEORAM] = 0x4c000000,
     [VE_ETHERNET] = 0x4e000000,
     [VE_USB] = 0x4f000000,
+    [VE_NORFLASHALIAS] = -1, /* not present */
 };
 
 static hwaddr motherboard_aseries_map[] = {
+    [VE_NORFLASHALIAS] = 0,
     /* CS0: 0x08000000 .. 0x0c000000 */
     [VE_NORFLASH0] = 0x08000000,
     /* CS4: 0x0c000000 .. 0x10000000 */
@@ -400,10 +403,13 @@ static void vexpress_common_init(const VEDBoardInfo *daughterboard,
     qemu_irq pic[64];
     uint32_t sys_id;
     DriveInfo *dinfo;
+    pflash_t *pflash0;
     ram_addr_t vram_size, sram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *vram = g_new(MemoryRegion, 1);
     MemoryRegion *sram = g_new(MemoryRegion, 1);
+    MemoryRegion *flashalias = g_new(MemoryRegion, 1);
+    MemoryRegion *flash0mem;
     const hwaddr *map = daughterboard->motherboard_map;
     int i;
 
@@ -471,15 +477,24 @@ static void vexpress_common_init(const VEDBoardInfo *daughterboard,
     sysbus_create_simple("pl111", map[VE_CLCD], pic[14]);
 
     dinfo = drive_get_next(IF_PFLASH);
-    if (!pflash_cfi01_register(map[VE_NORFLASH0], NULL, "vexpress.flash0",
+    pflash0 = pflash_cfi01_register(map[VE_NORFLASH0], NULL, "vexpress.flash0",
             VEXPRESS_FLASH_SIZE, dinfo ? dinfo->bdrv : NULL,
             VEXPRESS_FLASH_SECT_SIZE,
             VEXPRESS_FLASH_SIZE / VEXPRESS_FLASH_SECT_SIZE, 4,
-            0x00, 0x89, 0x00, 0x18, 0)) {
+            0x00, 0x89, 0x00, 0x18, 0);
+    if (!pflash0) {
         fprintf(stderr, "vexpress: error registering flash 0.\n");
         exit(1);
     }
 
+    if (map[VE_NORFLASHALIAS] != -1) {
+        /* Map flash 0 as an alias into low memory */
+        flash0mem = sysbus_mmio_get_region(SYS_BUS_DEVICE(pflash0), 0);
+        memory_region_init_alias(flashalias, NULL, "vexpress.flashalias",
+                                 flash0mem, 0, VEXPRESS_FLASH_SIZE);
+        memory_region_add_subregion(sysmem, map[VE_NORFLASHALIAS], flashalias);
+    }
+
     dinfo = drive_get_next(IF_PFLASH);
     if (!pflash_cfi01_register(map[VE_NORFLASH1], NULL, "vexpress.flash1",
             VEXPRESS_FLASH_SIZE, dinfo ? dinfo->bdrv : NULL,