[PATCH v2 04/30] hw/arm/raspi: Extract the RAM size from the board revision

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

The board revision encode the amount of RAM. Add a helper
to extract the RAM size, and use it.
Since the amount of RAM is fixed (it is impossible to physically
modify to have more or less RAM), do not allow sizes different
than the one anounced by the manufacturer.

Acked-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Cc: Alistair Francis <alistair@alistair23.me>

 hw/arm/raspi.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c
index 13d41dfce6..2f5cd32c5e 100644
--- a/hw/arm/raspi.c
+++ b/hw/arm/raspi.c
@@ -13,6 +13,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/units.h"
+#include "qemu/cutils.h"
 #include "qapi/error.h"
 #include "cpu.h"
 #include "hw/arm/bcm2836.h"
@@ -48,6 +49,12 @@ FIELD(REV_CODE, MANUFACTURER,      16, 4);
 FIELD(REV_CODE, MEMORY_SIZE,       20, 3);
 FIELD(REV_CODE, STYLE,             23, 1);
 
+static uint64_t board_ram_size(uint32_t board_rev)
+{
+    assert(FIELD_EX32(board_rev, REV_CODE, STYLE)); /* Only new style */
+    return 256 * MiB << FIELD_EX32(board_rev, REV_CODE, MEMORY_SIZE);
+}
+
 static int board_processor_id(uint32_t board_rev)
 {
     assert(FIELD_EX32(board_rev, REV_CODE, STYLE)); /* Only new style */
@@ -190,15 +197,17 @@ static void raspi_init(MachineState *machine, uint32_t board_rev)
 {
     RasPiState *s = g_new0(RasPiState, 1);
     int version = board_version(board_rev);
+    uint64_t ram_size = board_ram_size(board_rev);
     uint32_t vcram_size;
     DriveInfo *di;
     BlockBackend *blk;
     BusState *bus;
     DeviceState *carddev;
 
-    if (machine->ram_size > 1 * GiB) {
-        error_report("Requested ram size is too large for this machine: "
-                     "maximum is 1GB");
+    if (machine->ram_size != ram_size) {
+        char *size_str = size_to_str(ram_size);
+        error_report("This machine can only be used with %s", size_str);
+        g_free(size_str);
         exit(1);
     }
 
-- 
2.21.1