riscv: sifive_u: Instantiate OTP memory with a serial number

This adds an OTP memory with a given serial number to the sifive_u
machine. With such support, the upstream U-Boot for sifive_fu540
boots out of the box on the sifive_u machine.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

hw/riscv/sifive_u.c

@@ -10,6 +10,7 @@
  * 1) CLINT (Core Level Interruptor)
  * 2) PLIC (Platform Level Interrupt Controller)
  * 3) PRCI (Power, Reset, Clock, Interrupt)
+ * 4) OTP (One-Time Programmable) memory with stored serial number
  *
  * This board currently generates devicetree dynamically that indicates at least
  * two harts and up to five harts.
@@ -64,10 +65,12 @@ static const struct MemmapEntry {
     [SIFIVE_U_PRCI] =     { 0x10000000,     0x1000 },
     [SIFIVE_U_UART0] =    { 0x10010000,     0x1000 },
     [SIFIVE_U_UART1] =    { 0x10011000,     0x1000 },
+    [SIFIVE_U_OTP] =      { 0x10070000,     0x1000 },
     [SIFIVE_U_DRAM] =     { 0x80000000,        0x0 },
     [SIFIVE_U_GEM] =      { 0x100900FC,     0x2000 },
 };
 
+#define OTP_SERIAL          1
 #define GEM_REVISION        0x10070109
 
 static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
@@ -422,6 +425,9 @@ static void riscv_sifive_u_soc_init(Object *obj)
 
     sysbus_init_child_obj(obj, "prci", &s->prci, sizeof(s->prci),
                           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);
 }
@@ -498,6 +504,9 @@ 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);
 
+    object_property_set_bool(OBJECT(&s->otp), true, "realized", &err);
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->otp), 0, memmap[SIFIVE_U_OTP].base);
+
     for (i = 0; i < SIFIVE_U_PLIC_NUM_SOURCES; i++) {
         plic_gpios[i] = qdev_get_gpio_in(DEVICE(s->plic), i);
     }

include/hw/riscv/sifive_u.h

@@ -23,6 +23,7 @@
 #include "hw/riscv/riscv_hart.h"
 #include "hw/riscv/sifive_cpu.h"
 #include "hw/riscv/sifive_u_prci.h"
+#include "hw/riscv/sifive_u_otp.h"
 
 #define TYPE_RISCV_U_SOC "riscv.sifive.u.soc"
 #define RISCV_U_SOC(obj) \
@@ -39,6 +40,7 @@ typedef struct SiFiveUSoCState {
     RISCVHartArrayState u_cpus;
     DeviceState *plic;
     SiFiveUPRCIState prci;
+    SiFiveUOTPState otp;
     CadenceGEMState gem;
 } SiFiveUSoCState;
 
@@ -60,6 +62,7 @@ enum {
     SIFIVE_U_PRCI,
     SIFIVE_U_UART0,
     SIFIVE_U_UART1,
+    SIFIVE_U_OTP,
     SIFIVE_U_DRAM,
     SIFIVE_U_GEM
 };