memory_region_allocate_system_memory() API is going away, so
replace it with memdev allocated MemoryRegion. The later is
initialized by generic code, so board only needs to opt in
to memdev scheme by providing
  MachineClass::default_ram_id
and using MachineState::ram instead of manually initializing
RAM memory region.

PS:
 while at it add check for user supplied RAM size and error
 out if it mismatches board expected value.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/arm/mps2-tz.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/hw/arm/mps2-tz.c b/hw/arm/mps2-tz.c
index f8b620b..8e2ba59 100644
--- a/hw/arm/mps2-tz.c
+++ b/hw/arm/mps2-tz.c
@@ -79,7 +79,6 @@ typedef struct {
     MachineState parent;
 
     ARMSSE iotkit;
-    MemoryRegion psram;
     MemoryRegion ssram[3];
     MemoryRegion ssram1_m;
     MPS2SCC scc;
@@ -388,6 +387,12 @@ static void mps2tz_common_init(MachineState *machine)
         exit(1);
     }
 
+    if (machine->ram_size != mc->default_ram_size) {
+        error_report("Invalid RAM size, should be %" PRIi64 " Bytes",
+                     mc->default_ram_size);
+        exit(EXIT_FAILURE);
+    }
+
     sysbus_init_child_obj(OBJECT(machine), "iotkit", &mms->iotkit,
                           sizeof(mms->iotkit), mmc->armsse_type);
     iotkitdev = DEVICE(&mms->iotkit);
@@ -458,9 +463,7 @@ static void mps2tz_common_init(MachineState *machine)
      * tradeoffs. For QEMU they're all just RAM, though. We arbitrarily
      * call the 16MB our "system memory", as it's the largest lump.
      */
-    memory_region_allocate_system_memory(&mms->psram,
-                                         NULL, "mps.ram", 16 * MiB);
-    memory_region_add_subregion(system_memory, 0x80000000, &mms->psram);
+    memory_region_add_subregion(system_memory, 0x80000000, machine->ram);
 
     /* The overflow IRQs for all UARTs are ORed together.
      * Tx, Rx and "combined" IRQs are sent to the NVIC separately.
@@ -642,6 +645,7 @@ static void mps2tz_class_init(ObjectClass *oc, void *data)
 
     mc->init = mps2tz_common_init;
     iic->check = mps2_tz_idau_check;
+    mc->default_ram_id = "mps.ram";
 }
 
 static void mps2tz_an505_class_init(ObjectClass *oc, void *data)
@@ -657,6 +661,7 @@ static void mps2tz_an505_class_init(ObjectClass *oc, void *data)
     mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-m33");
     mmc->scc_id = 0x41045050;
     mmc->armsse_type = TYPE_IOTKIT;
+    mc->default_ram_size = 16 * MiB;
 }
 
 static void mps2tz_an521_class_init(ObjectClass *oc, void *data)
-- 
2.7.4