Re: [SPAM] [PATCH v4 5/5] hw/misc/aspeed_sbc: Add machine parameter to alias OTP drive property

[Cédric Le Goater]

On 7/8/25 07:57, Kane Chen wrote:

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

This patch adds a new machine parameter `otpmem` which creates a QOM
property alias on the aspeed_sbc device for the OTP drive.

Example usage:

   ./qemu-system-arm \
     -machine ast2600-evb,otpmem=otp-drive \
     -blockdev driver=file,filename=otpmem.img,node-name=otp \
     -global aspeed-otp.drive=otp \
     ...

With this change, the specified alias name (e.g. "otp-drive") becomes
available on the QOM path `/machine/soc/sbc/otp-drive`.

Signed-off-by: Kane-Chen-AS <kane_c...@aspeedtech.com>
---
  hw/arm/aspeed.c      | 20 ++++++++++++++++++++
  hw/misc/aspeed_sbc.c |  8 ++++++++
  2 files changed, 28 insertions(+)

diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
index c31bbe7701..8ec32369a6 100644
--- a/hw/arm/aspeed.c
+++ b/hw/arm/aspeed.c
@@ -48,6 +48,7 @@ struct AspeedMachineState {
      uint32_t uart_chosen;
      char *fmc_model;
      char *spi_model;
+    char *otpmem;
      uint32_t hw_strap1;
  };

@@ -1424,6 +1425,21 @@ static void aspeed_set_bmc_console(Object *obj, const char *value, Error **errp)

      bmc->uart_chosen = val + ASPEED_DEV_UART0;
  }

+static char *aspeed_get_otpmem(Object *obj, Error **errp)

+{
+    AspeedMachineState *bmc = ASPEED_MACHINE(obj);
+
+    return g_strdup(bmc->otpmem);
+}
+
+static void aspeed_set_otpmem(Object *obj, const char *value, Error **errp)
+{
+    AspeedMachineState *bmc = ASPEED_MACHINE(obj);
+
+    g_free(bmc->otpmem);
+    bmc->otpmem = g_strdup(value);
+}
+
  static void aspeed_machine_class_props_init(ObjectClass *oc)
  {
      object_class_property_add_bool(oc, "execute-in-place",
@@ -1445,6 +1461,10 @@ static void aspeed_machine_class_props_init(ObjectClass 
*oc)
                                     aspeed_set_spi_model);
      object_class_property_set_description(oc, "spi-model",
                                            "Change the SPI Flash model");
+    object_class_property_add_str(oc, "otpmem", aspeed_get_otpmem,
+                                   aspeed_set_otpmem);
+    object_class_property_set_description(oc, "otpmem",
+                                          "Set OTP Memory type");
  }

static void aspeed_machine_class_init_cpus_defaults(MachineClass *mc)

diff --git a/hw/misc/aspeed_sbc.c b/hw/misc/aspeed_sbc.c
index b56a8b7678..b82c5e37cc 100644
--- a/hw/misc/aspeed_sbc.c
+++ b/hw/misc/aspeed_sbc.c
@@ -209,10 +209,18 @@ static void aspeed_sbc_instance_init(Object *obj)
  {
      AspeedSBCClass *sc = ASPEED_SBC_GET_CLASS(obj);
      AspeedSBCState *s = ASPEED_SBC(obj);
+    char *otpname;

if (sc->has_otp) {

          object_initialize_child(OBJECT(s), "otp", &s->otp,
                                  TYPE_ASPEED_OTP);
+        otpname = object_property_get_str(qdev_get_machine(),
+                                          "otpmem",> +                             
             &error_abort);

This is a hack and I would prefer to prevent device models from
accessing directly the machine.

It would have been nice to have a machine option, but since the
user can specify a file for the OTP backend from the command line,
let's leave it as is.


Thanks,

C.

+        if (strlen(otpname)) {
+            object_property_add_alias(obj, otpname,
+                                      OBJECT(&s->otp), "drive");
+        }
      }
  }