Re: [PATCH v4 18/19] hw/arm/aspeed: Model AST1700 I3C block as unimplemented device

Wed, 24 Dec 2025 02:44:05 -0800 

On 12/24/25 02:41, Kane Chen via wrote:

From: Kane-Chen-AS <[email protected]>

AST1700 exposes more I3C buses than the current dummy I3C model
provides. When Linux probes the I3C devices on AST1700 this mismatch
can trigger a kernel panic. Model the I3C block as an unimplemented
device to make the missing functionality explicit and avoid unexpected
side effects.

This wires up the I3C interrupt lines for the IO expanders and adds the
corresponding device entries for the AST1700 model.

No functional I3C emulation is provided yet; this only prevents crashes and
documents the missing piece.

Signed-off-by: Kane-Chen-AS <[email protected]>


Reviewed-by: Cédric Le Goater <[email protected]>

Thanks,

C.


---
  include/hw/arm/aspeed_ast1700.h |  3 +++
  include/hw/arm/aspeed_soc.h     |  2 ++
  hw/arm/aspeed_ast1700.c         | 15 +++++++++++++++
  hw/arm/aspeed_ast27x0.c         | 18 ++++++++++++++++--
  4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/include/hw/arm/aspeed_ast1700.h b/include/hw/arm/aspeed_ast1700.h
index 490f2a3b05..874b4d63fe 100644
--- a/include/hw/arm/aspeed_ast1700.h
+++ b/include/hw/arm/aspeed_ast1700.h
@@ -19,6 +19,7 @@
  #include "hw/ssi/aspeed_smc.h"
  #include "hw/watchdog/wdt_aspeed.h"
  #include "hw/char/serial-mm.h"
+#include "hw/misc/unimp.h"
#define AST1700_SGPIO_NUM 2 
  #define AST1700_WDT_NUM              9
@@ -45,6 +46,8 @@ struct AspeedAST1700SoCState {
      AspeedI2CState i2c;
      AspeedPWMState pwm;
      AspeedWDTState wdt[AST1700_WDT_NUM];
+
+    UnimplementedDeviceState i3c;
  };
#endif /* ASPEED_AST1700_H */ 
diff --git a/include/hw/arm/aspeed_soc.h b/include/hw/arm/aspeed_soc.h
index 4ea2521041..b185b04186 100644
--- a/include/hw/arm/aspeed_soc.h
+++ b/include/hw/arm/aspeed_soc.h
@@ -294,6 +294,8 @@ enum {
      ASPEED_DEV_IOEXP1_I2C,
      ASPEED_DEV_IOEXP0_INTCIO,
      ASPEED_DEV_IOEXP1_INTCIO,
+    ASPEED_DEV_IOEXP0_I3C,
+    ASPEED_DEV_IOEXP1_I3C,
  };
const char *aspeed_soc_cpu_type(const char * const *valid_cpu_types); 
diff --git a/hw/arm/aspeed_ast1700.c b/hw/arm/aspeed_ast1700.c
index ca0ce4e2c2..5f3c56e6cc 100644
--- a/hw/arm/aspeed_ast1700.c
+++ b/hw/arm/aspeed_ast1700.c
@@ -15,6 +15,7 @@
#define AST2700_SOC_LTPI_SIZE 0x01000000 
  #define AST1700_SOC_SRAM_SIZE        0x00040000
+#define AST1700_SOC_I3C_SIZE         0x00010000
enum { 
      ASPEED_AST1700_DEV_SPI0,
@@ -26,6 +27,7 @@ enum {
      ASPEED_AST1700_DEV_SGPIOM0,
      ASPEED_AST1700_DEV_SGPIOM1,
      ASPEED_AST1700_DEV_I2C,
+    ASPEED_AST1700_DEV_I3C,
      ASPEED_AST1700_DEV_UART12,
      ASPEED_AST1700_DEV_LTPI_CTRL,
      ASPEED_AST1700_DEV_WDT,
@@ -42,6 +44,7 @@ static const hwaddr aspeed_ast1700_io_memmap[] = {
      [ASPEED_AST1700_DEV_SGPIOM0]   =  0x00C0C000,
      [ASPEED_AST1700_DEV_SGPIOM1]   =  0x00C0D000,
      [ASPEED_AST1700_DEV_I2C]       =  0x00C0F000,
+    [ASPEED_AST1700_DEV_I3C]       =  0x00C20000,
      [ASPEED_AST1700_DEV_UART12]    =  0x00C33B00,
      [ASPEED_AST1700_DEV_LTPI_CTRL] =  0x00C34000,
      [ASPEED_AST1700_DEV_WDT]       =  0x00C37000,
@@ -172,6 +175,14 @@ static void aspeed_ast1700_realize(DeviceState *dev, Error 
**errp)
                          sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->wdt[i]), 
0));
      }
+ /* I3C */ 
+    qdev_prop_set_string(DEVICE(&s->i3c), "name", "ioexp-i3c");
+    qdev_prop_set_uint64(DEVICE(&s->i3c), "size", AST1700_SOC_I3C_SIZE);
+    sysbus_realize(SYS_BUS_DEVICE(&s->i3c), errp);
+    memory_region_add_subregion_overlap(&s->iomem,
+                        aspeed_ast1700_io_memmap[ASPEED_AST1700_DEV_I3C],
+                        sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->i3c), 0),
+                        -1000);
  }
static void aspeed_ast1700_instance_init(Object *obj) 
@@ -221,6 +232,10 @@ static void aspeed_ast1700_instance_init(Object *obj)
                                  &s->wdt[i], "aspeed.wdt-ast2700");
      }
+ /* I3C */ 
+    object_initialize_child(obj, "ioexp-i3c[*]", &s->i3c,
+                            TYPE_UNIMPLEMENTED_DEVICE);
+
      return;
  }
diff --git a/hw/arm/aspeed_ast27x0.c b/hw/arm/aspeed_ast27x0.c 
index ca3adf9a50..0807481162 100644
--- a/hw/arm/aspeed_ast27x0.c
+++ b/hw/arm/aspeed_ast27x0.c
@@ -206,7 +206,9 @@ static const int aspeed_soc_ast2700a1_irqmap[] = {
      [ASPEED_DEV_PECI]      = 197,
      [ASPEED_DEV_SDHCI]     = 197,
      [ASPEED_DEV_IOEXP0_I2C] = 198,
+    [ASPEED_DEV_IOEXP0_I3C] = 199,
      [ASPEED_DEV_IOEXP1_I2C] = 200,
+    [ASPEED_DEV_IOEXP1_I3C] = 201,
  };
/* GICINT 128 */ 
@@ -275,12 +277,24 @@ static const int ast2700_gic198_intcmap[] = {
      [ASPEED_DEV_IOEXP0_I2C]       = 0, /* 0 - 15 */
  };
+/* Primary AST1700 Interrupts */ 
+/* A1: GINTC 199 */
+static const int ast2700_gic199_intcmap[] = {
+    [ASPEED_DEV_IOEXP0_I3C]       = 0, /* 0 - 15 */
+};
+
  /* Secondary AST1700 Interrupts */
  /* A1: GINTC 200 */
  static const int ast2700_gic200_intcmap[] = {
      [ASPEED_DEV_IOEXP1_I2C]       = 0, /* 0 - 15 */
  };
+/* Secondary AST1700 Interrupts */ 
+/* A1: GINTC 201 */
+static const int ast2700_gic201_intcmap[] = {
+    [ASPEED_DEV_IOEXP1_I3C]       = 0, /* 0 - 15 */
+};
+
  /* GICINT 128 ~ 136 */
  /* GICINT 192 ~ 201 */
  struct gic_intc_irq_info {
@@ -298,9 +312,9 @@ static const struct gic_intc_irq_info ast2700_gic_intcmap[] 
= {
      {196, 1, 4, ast2700_gic132_gic196_intcmap},
      {197, 1, 5, ast2700_gic133_gic197_intcmap},
      {198, 2, 0, ast2700_gic198_intcmap},
-    {199, 1, 7, NULL},
+    {199, 2, 1, ast2700_gic199_intcmap},
      {200, 3, 0, ast2700_gic200_intcmap},
-    {201, 1, 9, NULL},
+    {201, 3, 1, ast2700_gic201_intcmap},
      {128, 0, 1, ast2700_gic128_gic192_intcmap},
      {129, 0, 2, NULL},
      {130, 0, 3, ast2700_gic130_gic194_intcmap},

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