sm501: Add missing arbitration control register

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: d1eaf3b19c40aeb32a343a211f2b56664a67f948.1492787889.git.balaton@eik.bme.hu
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/display/sm501.c

@@ -474,6 +474,7 @@ typedef struct SM501State {
     uint32_t gpio_31_0_control;
     uint32_t gpio_63_32_control;
     uint32_t dram_control;
+    uint32_t arbitration_control;
     uint32_t irq_mask;
     uint32_t misc_timing;
     uint32_t power_mode_control;
@@ -757,6 +758,9 @@ static uint64_t sm501_system_config_read(void *opaque, hwaddr addr,
     case SM501_DRAM_CONTROL:
         ret = (s->dram_control & 0x07F107C0) | s->local_mem_size_index << 13;
         break;
+    case SM501_ARBTRTN_CONTROL:
+        ret = s->arbitration_control;
+        break;
     case SM501_IRQ_MASK:
         ret = s->irq_mask;
         break;
@@ -809,6 +813,9 @@ static void sm501_system_config_write(void *opaque, hwaddr addr,
         /* TODO : check validity of size change */
         s->dram_control |=  value & 0x7FFFFFC3;
         break;
+    case SM501_ARBTRTN_CONTROL:
+        s->arbitration_control =  value & 0x37777777;
+        break;
     case SM501_IRQ_MASK:
         s->irq_mask = value;
         break;
@@ -1422,6 +1429,7 @@ void sm501_init(MemoryRegion *address_space_mem, uint32_t base,
      *  BUS = 0 : Hitachi SH3/SH4
      */
     s->misc_control = SM501_MISC_DAC_POWER;
+    s->arbitration_control = 0x05146732;
     s->dc_panel_control = 0x00010000; /* FIFO level 3 */
     s->dc_crt_control = 0x00010000;