Re: [PATCH v2 16/17] hw/arm/aspeed: Model AST1700 SGPIOM block as unimplemented device

[Cédric Le Goater]

Hello,

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

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

AST1700 includes an SGPIOM block, but QEMU has no functional model yet.

Does the series  "hw/gpio: Add Aspeed Serial GPIO (SGPIO) controller" [1] 
proposed
by Yubin Zou fill this gap ?

Thanks,

C.

[1] 
https://lore.kernel.org//qemu-devel/20251106-aspeed-sgpio-v1-0-b02609371...@google.com

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 4048d31154..8ada3a7775 100644
--- a/include/hw/misc/aspeed_ast1700.h
+++ b/include/hw/misc/aspeed_ast1700.h
@@ -44,6 +44,7 @@ struct AspeedAST1700SoCState {
      AspeedWDTState wdt[AST1700_WDT_NUM];

UnimplementedDeviceState i3c;

+    UnimplementedDeviceState sgpiom;
  };

#endif /* ASPEED_AST1700_H */

diff --git a/hw/misc/aspeed_ast1700.c b/hw/misc/aspeed_ast1700.c
index 37b2946fc0..66a5f21d27 100644
--- a/hw/misc/aspeed_ast1700.c
+++ b/hw/misc/aspeed_ast1700.c
@@ -19,6 +19,7 @@
  #define AST2700_SOC_LTPI_SIZE        0x01000000
  #define AST1700_SOC_SRAM_SIZE        0x00040000
  #define AST1700_SOC_I3C_SIZE         0x00010000
+#define AST1700_SOC_SGPIOM_SIZE      0x00002000

enum {

      ASPEED_AST1700_DEV_SPI0,
@@ -26,6 +27,7 @@ enum {
      ASPEED_AST1700_DEV_ADC,
      ASPEED_AST1700_DEV_SCU,
      ASPEED_AST1700_DEV_GPIO,
+    ASPEED_AST1700_DEV_SGPIOM,
      ASPEED_AST1700_DEV_I2C,
      ASPEED_AST1700_DEV_I3C,
      ASPEED_AST1700_DEV_UART12,
@@ -40,6 +42,7 @@ static const hwaddr aspeed_ast1700_io_memmap[] = {
      [ASPEED_AST1700_DEV_ADC]       =  0x00C00000,
      [ASPEED_AST1700_DEV_SCU]       =  0x00C02000,
      [ASPEED_AST1700_DEV_GPIO]      =  0x00C0B000,
+    [ASPEED_AST1700_DEV_SGPIOM]    =  0x00C0C000,
      [ASPEED_AST1700_DEV_I2C]       =  0x00C0F000,
      [ASPEED_AST1700_DEV_I3C]       =  0x00C20000,
      [ASPEED_AST1700_DEV_UART12]    =  0x00C33B00,
@@ -162,6 +165,15 @@ static void aspeed_ast1700_realize(DeviceState *dev, Error 
**errp)
                          
aspeed_ast1700_io_memmap[ASPEED_AST1700_DEV_LTPI_CTRL],
                          sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->ltpi), 0));

+ /* SGPIOM */

+    qdev_prop_set_string(DEVICE(&s->sgpiom), "name", "ioexp-sgpiom");
+    qdev_prop_set_uint64(DEVICE(&s->sgpiom), "size", AST1700_SOC_SGPIOM_SIZE);
+    sysbus_realize(SYS_BUS_DEVICE(&s->sgpiom), errp);
+    memory_region_add_subregion_overlap(&s->iomem,
+                        aspeed_ast1700_io_memmap[ASPEED_AST1700_DEV_SGPIOM],
+                        sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->sgpiom), 0),
+                        -1000);
+
      /* WDT */
      for (i = 0; i < AST1700_WDT_NUM; i++) {
          AspeedWDTClass *awc = ASPEED_WDT_GET_CLASS(&s->wdt[i]);
@@ -225,6 +237,10 @@ static void aspeed_ast1700_instance_init(Object *obj)
      object_initialize_child(obj, "ltpi-ctrl",
                              &s->ltpi, TYPE_ASPEED_LTPI);

+ /* SGPIOM */

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