[PATCH v2] riscv: sifive_u: Add a "serial" property for board serial number

[Bin Meng <bmeng.cn@gmail.com>]

At present the board serial number is hard-coded to 1, and passed
to OTP model during initialization. Firmware (FSBL, U-Boot) uses
the serial number to generate a unique MAC address for the on-chip
ethernet controller. When multiple QEMU 'sifive_u' instances are
created and connected to the same subnet, they all have the same
MAC address hence it creates a unusable network.

A new "serial" property is introduced to specify the board serial
number. When not given, the default serial number 1 is used.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

---

Changes in v2:
- Move setting OTP serial number property from riscv_sifive_u_soc_init()
  to riscv_sifive_u_soc_realize(), to fix the 'check-qtest-riscv' error.
  I am not really sure why doing so could fix the 'make check' error.
  The v1 patch worked fine and nothing seems wrong.

 hw/riscv/sifive_u.c         | 21 ++++++++++++++++++++-
 include/hw/riscv/sifive_u.h |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index 0e12b3c..ca561d3 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -34,6 +34,7 @@
 #include "qemu/log.h"
 #include "qemu/error-report.h"
 #include "qapi/error.h"
+#include "qapi/visitor.h"
 #include "hw/boards.h"
 #include "hw/loader.h"
 #include "hw/sysbus.h"
@@ -434,7 +435,6 @@ static void riscv_sifive_u_soc_init(Object *obj)
                           TYPE_SIFIVE_U_PRCI);
     sysbus_init_child_obj(obj, "otp", &s->otp, sizeof(s->otp),
                           TYPE_SIFIVE_U_OTP);
-    qdev_prop_set_uint32(DEVICE(&s->otp), "serial", OTP_SERIAL);
     sysbus_init_child_obj(obj, "gem", &s->gem, sizeof(s->gem),
                           TYPE_CADENCE_GEM);
 }
@@ -453,6 +453,18 @@ static void sifive_u_set_start_in_flash(Object *obj, bool value, Error **errp)
     s->start_in_flash = value;
 }
 
+static void sifive_u_get_serial(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    visit_type_uint32(v, name, (uint32_t *)opaque, errp);
+}
+
+static void sifive_u_set_serial(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    visit_type_uint32(v, name, (uint32_t *)opaque, errp);
+}
+
 static void riscv_sifive_u_machine_instance_init(Object *obj)
 {
     SiFiveUState *s = RISCV_U_MACHINE(obj);
@@ -464,11 +476,17 @@ static void riscv_sifive_u_machine_instance_init(Object *obj)
                                     "Set on to tell QEMU's ROM to jump to " \
                                     "flash. Otherwise QEMU will jump to DRAM",
                                     NULL);
+
+    s->serial = OTP_SERIAL;
+    object_property_add(obj, "serial", "uint32", sifive_u_get_serial,
+                        sifive_u_set_serial, NULL, &s->serial, NULL);
+    object_property_set_description(obj, "serial", "Board serial number", NULL);
 }
 
 static void riscv_sifive_u_soc_realize(DeviceState *dev, Error **errp)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
+    SiFiveUState *us = RISCV_U_MACHINE(ms);
     SiFiveUSoCState *s = RISCV_U_SOC(dev);
     const struct MemmapEntry *memmap = sifive_u_memmap;
     MemoryRegion *system_memory = get_system_memory();
@@ -554,6 +572,7 @@ static void riscv_sifive_u_soc_realize(DeviceState *dev, Error **errp)
     object_property_set_bool(OBJECT(&s->prci), true, "realized", &err);
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->prci), 0, memmap[SIFIVE_U_PRCI].base);
 
+    qdev_prop_set_uint32(DEVICE(&s->otp), "serial", us->serial);
     object_property_set_bool(OBJECT(&s->otp), true, "realized", &err);
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->otp), 0, memmap[SIFIVE_U_OTP].base);
 
diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h
index 82667b5..7cf742e 100644
--- a/include/hw/riscv/sifive_u.h
+++ b/include/hw/riscv/sifive_u.h
@@ -59,6 +59,7 @@ typedef struct SiFiveUState {
     int fdt_size;
 
     bool start_in_flash;
+    uint32_t serial;
 } SiFiveUState;
 
 enum {
-- 
2.7.4