hw/misc/allwinner-dramc: Do not use SysBus API to map local MMIO region

There is no point in exposing an internal MMIO region via
SysBus and directly mapping it in the very same device.

Just map it without using the SysBus API.

Transformation done using the following coccinelle script:

  @@
  expression sbdev;
  expression index;
  expression addr;
  expression subregion;
  @@
  -    sysbus_init_mmio(sbdev, subregion);
       ... when != sbdev
  -    sysbus_mmio_map(sbdev, index, addr);
  +    memory_region_add_subregion(get_system_memory(),
  +                                addr, subregion);

  @@
  expression priority;
  @@
  -    sysbus_init_mmio(sbdev, subregion);
       ... when != sbdev
  -    sysbus_mmio_map_overlap(sbdev, index, addr, priority);
  +    memory_region_add_subregion_overlap(get_system_memory(),
  +                                        addr,
  +                                        subregion, priority);

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20231019071611.98885-5-philmd@linaro.org>

hw/misc/allwinner-r40-dramc.c

@@ -414,31 +414,30 @@ static void allwinner_r40_dramc_reset(DeviceState *dev)
 static void allwinner_r40_dramc_realize(DeviceState *dev, Error **errp)
 {
     AwR40DramCtlState *s = AW_R40_DRAMC(dev);
-    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 
     if (!get_match_ddr(s->ram_size)) {
         error_report("%s: ram-size %u MiB is not supported",
                         __func__, s->ram_size);
         exit(1);
     }
 
-    /* R40 support max 2G memory but we only support up to 1G now. index 3 */
+    /* R40 support max 2G memory but we only support up to 1G now. */
     memory_region_init_io(&s->detect_cells, OBJECT(s),
                           &allwinner_r40_detect_ops, s,
                           "DRAMCELLS", 1 * GiB);
-    sysbus_init_mmio(sbd, &s->detect_cells);
-    sysbus_mmio_map_overlap(sbd, 3, s->ram_addr, 10);
+    memory_region_add_subregion_overlap(get_system_memory(), s->ram_addr,
+                                        &s->detect_cells, 10);
     memory_region_set_enabled(&s->detect_cells, false);
 
     /*
      * We only support DRAM size up to 1G now, so prepare a high memory page
-     * after 1G for dualrank detect. index = 4
+     * after 1G for dualrank detect.
      */
     memory_region_init_io(&s->dram_high, OBJECT(s),
                             &allwinner_r40_dualrank_detect_ops, s,
                             "DRAMHIGH", KiB);
-    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->dram_high);
-    sysbus_mmio_map(SYS_BUS_DEVICE(s), 4, s->ram_addr + GiB);
+    memory_region_add_subregion(get_system_memory(), s->ram_addr + GiB,
+                                &s->dram_high);
 }
 
 static void allwinner_r40_dramc_init(Object *obj)