[PATCH v3 04/13] 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>
---
v3: Try to make error message clearer (Zoltan)
I used the same string as "ppc/ppc405_boards: add RAM size checks"
https://www.mail-archive.com/qemu-devel@nongnu.org/msg675801.html
---
 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 f285e2988f..dcd8d2d6d3 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"
@@ -49,6 +50,12 @@ 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 */
@@ -191,15 +198,17 @@ 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("Invalid RAM size, should be %s", size_str);
+        g_free(size_str);
         exit(1);
     }
 
-- 
2.21.1