lm32/milkymist: use memdev for RAM

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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200219160953.13771-46-imammedo@redhat.com>

hw/lm32/milkymist.c

@@ -36,6 +36,7 @@
 #include "hw/display/milkymist_tmu2.h"
 #include "lm32.h"
 #include "exec/address-spaces.h"
+#include "qemu/cutils.h"
 
 #define BIOS_FILENAME    "mmone-bios.bin"
 #define BIOS_OFFSET      0x00860000
@@ -82,6 +83,7 @@ static void main_cpu_reset(void *opaque)
 static void
 milkymist_init(MachineState *machine)
 {
+    MachineClass *mc = MACHINE_GET_CLASS(machine);
     const char *kernel_filename = machine->kernel_filename;
     const char *kernel_cmdline = machine->kernel_cmdline;
     const char *initrd_filename = machine->initrd_filename;
@@ -90,22 +92,27 @@ milkymist_init(MachineState *machine)
     int kernel_size;
     DriveInfo *dinfo;
     MemoryRegion *address_space_mem = get_system_memory();
-    MemoryRegion *phys_sdram = g_new(MemoryRegion, 1);
     qemu_irq irq[32];
     int i;
     char *bios_filename;
     ResetInfo *reset_info;
 
+    if (machine->ram_size != mc->default_ram_size) {
+        char *sz = size_to_str(mc->default_ram_size);
+        error_report("Invalid RAM size, should be %s", sz);
+        g_free(sz);
+        exit(EXIT_FAILURE);
+    }
+
     /* memory map */
     hwaddr flash_base   = 0x00000000;
     size_t flash_sector_size        = 128 * KiB;
     size_t flash_size               = 32 * MiB;
     hwaddr sdram_base   = 0x40000000;
-    size_t sdram_size               = 128 * MiB;
 
     hwaddr initrd_base  = sdram_base + 0x1002000;
     hwaddr cmdline_base = sdram_base + 0x1000000;
-    size_t initrd_max = sdram_size - 0x1002000;
+    size_t initrd_max = machine->ram_size - 0x1002000;
 
     reset_info = g_malloc0(sizeof(ResetInfo));
 
@@ -116,9 +123,7 @@ milkymist_init(MachineState *machine)
 
     cpu_lm32_set_phys_msb_ignore(env, 1);
 
-    memory_region_allocate_system_memory(phys_sdram, NULL, "milkymist.sdram",
-                                         sdram_size);
-    memory_region_add_subregion(address_space_mem, sdram_base, phys_sdram);
+    memory_region_add_subregion(address_space_mem, sdram_base, machine->ram);
 
     dinfo = drive_get(IF_PFLASH, 0, 0);
     /* Numonyx JS28F256J3F105 */
@@ -183,7 +188,7 @@ milkymist_init(MachineState *machine)
 
         if (kernel_size < 0) {
             kernel_size = load_image_targphys(kernel_filename, sdram_base,
-                                              sdram_size);
+                                              machine->ram_size);
             reset_info->bootstrap_pc = sdram_base;
         }
 
@@ -216,6 +221,8 @@ static void milkymist_machine_init(MachineClass *mc)
     mc->init = milkymist_init;
     mc->is_default = 0;
     mc->default_cpu_type = LM32_CPU_TYPE_NAME("lm32-full");
+    mc->default_ram_size = 128 * MiB;
+    mc->default_ram_id = "milkymist.sdram";
 }
 
 DEFINE_MACHINE("milkymist", milkymist_machine_init)