Re: [PATCH v2 17/17] hw/arm/aspeed: Model AST1700 PWM block as unimplemented device

[Cédric Le Goater]

On 11/5/25 04:58, Kane Chen wrote:

From: Kane-Chen-AS <kane_c...@aspeedtech.com>

AST1700 includes an PWM block, but QEMU has no functional model for

aspeed product yet.

We could start with a dummy PWM model :

  
https://github.com/legoater/qemu/commit/9d77c84b04c2d9ae5685b3ccb5c434873666ca78

Feel free to add to your series.

Thanks,

C.



Expose it as an unimplemented device so the

address space is reserved and the missing functionality is explicit
to users/guests.

Signed-off-by: Kane-Chen-AS <kane_c...@aspeedtech.com>
---
  include/hw/misc/aspeed_ast1700.h |  1 +
  hw/misc/aspeed_ast1700.c         | 16 ++++++++++++++++
  2 files changed, 17 insertions(+)

diff --git a/include/hw/misc/aspeed_ast1700.h b/include/hw/misc/aspeed_ast1700.h
index 8ada3a7775..9d432a7db0 100644
--- a/include/hw/misc/aspeed_ast1700.h
+++ b/include/hw/misc/aspeed_ast1700.h
@@ -45,6 +45,7 @@ struct AspeedAST1700SoCState {

UnimplementedDeviceState i3c;

      UnimplementedDeviceState sgpiom;
+    UnimplementedDeviceState pwm;
  };

#endif /* ASPEED_AST1700_H */

diff --git a/hw/misc/aspeed_ast1700.c b/hw/misc/aspeed_ast1700.c
index 66a5f21d27..3d9a920a7a 100644
--- a/hw/misc/aspeed_ast1700.c
+++ b/hw/misc/aspeed_ast1700.c
@@ -20,9 +20,11 @@
  #define AST1700_SOC_SRAM_SIZE        0x00040000
  #define AST1700_SOC_I3C_SIZE         0x00010000
  #define AST1700_SOC_SGPIOM_SIZE      0x00002000
+#define AST1700_SOC_PWM_SIZE         0x00000200

enum {

      ASPEED_AST1700_DEV_SPI0,
+    ASPEED_AST1700_DEV_PWM,
      ASPEED_AST1700_DEV_SRAM,
      ASPEED_AST1700_DEV_ADC,
      ASPEED_AST1700_DEV_SCU,
@@ -38,6 +40,7 @@ enum {

static const hwaddr aspeed_ast1700_io_memmap[] = {

      [ASPEED_AST1700_DEV_SPI0]      =  0x00030000,
+    [ASPEED_AST1700_DEV_PWM]       =  0x000C0000,
      [ASPEED_AST1700_DEV_SRAM]      =  0x00BC0000,
      [ASPEED_AST1700_DEV_ADC]       =  0x00C00000,
      [ASPEED_AST1700_DEV_SCU]       =  0x00C02000,
@@ -174,6 +177,15 @@ static void aspeed_ast1700_realize(DeviceState *dev, Error 
**errp)
                          sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->sgpiom), 0),
                          -1000);

+ /* PWM */

+    qdev_prop_set_string(DEVICE(&s->pwm), "name", "ioexp-pwm");
+    qdev_prop_set_uint64(DEVICE(&s->pwm), "size", AST1700_SOC_PWM_SIZE);
+    sysbus_realize(SYS_BUS_DEVICE(&s->pwm), errp);
+    memory_region_add_subregion_overlap(&s->iomem,
+                        aspeed_ast1700_io_memmap[ASPEED_AST1700_DEV_PWM],
+                        sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->pwm), 0),
+                        -1000);
+
      /* WDT */
      for (i = 0; i < AST1700_WDT_NUM; i++) {
          AspeedWDTClass *awc = ASPEED_WDT_GET_CLASS(&s->wdt[i]);
@@ -241,6 +253,10 @@ static void aspeed_ast1700_instance_init(Object *obj)
      object_initialize_child(obj, "ioexp-sgpiom[*]", &s->sgpiom,
                              TYPE_UNIMPLEMENTED_DEVICE);

+ /* PWM */

+    object_initialize_child(obj, "ioexp-pwm", &s->pwm,
+                            TYPE_UNIMPLEMENTED_DEVICE);
+
      /* WDT */
      for (i = 0; i < AST1700_WDT_NUM; i++) {
          snprintf(typename, sizeof(typename), "aspeed.wdt-%s", socname);