riscv: sifive: Implement a model for SiFive FU540 OTP

This implements a simple model for SiFive FU540 OTP (One-Time
Programmable) Memory interface, primarily for reading out the
stored serial number from the first 1 KiB of the 16 KiB OTP
memory reserved by SiFive for internal use.

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>

2 files changed, 192 insertions, 0 deletions

diff --git a/hw/riscv/Makefile.objs b/hw/riscv/Makefile.objs
index b95bbd51e2..fc3c6dd7c8 100644
--- a/hw/riscv/Makefile.objs
+++ b/hw/riscv/Makefile.objs
@@ -8,6 +8,7 @@ obj-$(CONFIG_SIFIVE) += sifive_gpio.o
 obj-$(CONFIG_SIFIVE) += sifive_plic.o
 obj-$(CONFIG_SIFIVE) += sifive_test.o
 obj-$(CONFIG_SIFIVE_U) += sifive_u.o
+obj-$(CONFIG_SIFIVE_U) += sifive_u_otp.o
 obj-$(CONFIG_SIFIVE_U) += sifive_u_prci.o
 obj-$(CONFIG_SIFIVE) += sifive_uart.o
 obj-$(CONFIG_SPIKE) += spike.o
diff --git a/hw/riscv/sifive_u_otp.c b/hw/riscv/sifive_u_otp.c
new file mode 100644
index 0000000000..ea0eee5678
--- /dev/null
+++ b/hw/riscv/sifive_u_otp.c
@@ -0,0 +1,191 @@
+/*
+ * QEMU SiFive U OTP (One-Time Programmable) Memory interface
+ *
+ * Copyright (c) 2019 Bin Meng <bmeng.cn@gmail.com>
+ *
+ * Simple model of the OTP to emulate register reads made by the SDK BSP
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/qdev-properties.h"
+#include "hw/sysbus.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "hw/riscv/sifive_u_otp.h"
+
+static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    SiFiveUOTPState *s = opaque;
+
+    switch (addr) {
+    case SIFIVE_U_OTP_PA:
+        return s->pa;
+    case SIFIVE_U_OTP_PAIO:
+        return s->paio;
+    case SIFIVE_U_OTP_PAS:
+        return s->pas;
+    case SIFIVE_U_OTP_PCE:
+        return s->pce;
+    case SIFIVE_U_OTP_PCLK:
+        return s->pclk;
+    case SIFIVE_U_OTP_PDIN:
+        return s->pdin;
+    case SIFIVE_U_OTP_PDOUT:
+        if ((s->pce & SIFIVE_U_OTP_PCE_EN) &&
+            (s->pdstb & SIFIVE_U_OTP_PDSTB_EN) &&
+            (s->ptrim & SIFIVE_U_OTP_PTRIM_EN)) {
+            return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
+        } else {
+            return 0xff;
+        }
+    case SIFIVE_U_OTP_PDSTB:
+        return s->pdstb;
+    case SIFIVE_U_OTP_PPROG:
+        return s->pprog;
+    case SIFIVE_U_OTP_PTC:
+        return s->ptc;
+    case SIFIVE_U_OTP_PTM:
+        return s->ptm;
+    case SIFIVE_U_OTP_PTM_REP:
+        return s->ptm_rep;
+    case SIFIVE_U_OTP_PTR:
+        return s->ptr;
+    case SIFIVE_U_OTP_PTRIM:
+        return s->ptrim;
+    case SIFIVE_U_OTP_PWE:
+        return s->pwe;
+    }
+
+    qemu_log_mask(LOG_GUEST_ERROR, "%s: read: addr=0x%" HWADDR_PRIx "\n",
+                  __func__, addr);
+    return 0;
+}
+
+static void sifive_u_otp_write(void *opaque, hwaddr addr,
+                               uint64_t val64, unsigned int size)
+{
+    SiFiveUOTPState *s = opaque;
+    uint32_t val32 = (uint32_t)val64;
+
+    switch (addr) {
+    case SIFIVE_U_OTP_PA:
+        s->pa = val32 & SIFIVE_U_OTP_PA_MASK;
+        break;
+    case SIFIVE_U_OTP_PAIO:
+        s->paio = val32;
+        break;
+    case SIFIVE_U_OTP_PAS:
+        s->pas = val32;
+        break;
+    case SIFIVE_U_OTP_PCE:
+        s->pce = val32;
+        break;
+    case SIFIVE_U_OTP_PCLK:
+        s->pclk = val32;
+        break;
+    case SIFIVE_U_OTP_PDIN:
+        s->pdin = val32;
+        break;
+    case SIFIVE_U_OTP_PDOUT:
+        /* read-only */
+        break;
+    case SIFIVE_U_OTP_PDSTB:
+        s->pdstb = val32;
+        break;
+    case SIFIVE_U_OTP_PPROG:
+        s->pprog = val32;
+        break;
+    case SIFIVE_U_OTP_PTC:
+        s->ptc = val32;
+        break;
+    case SIFIVE_U_OTP_PTM:
+        s->ptm = val32;
+        break;
+    case SIFIVE_U_OTP_PTM_REP:
+        s->ptm_rep = val32;
+        break;
+    case SIFIVE_U_OTP_PTR:
+        s->ptr = val32;
+        break;
+    case SIFIVE_U_OTP_PTRIM:
+        s->ptrim = val32;
+        break;
+    case SIFIVE_U_OTP_PWE:
+        s->pwe = val32;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%" HWADDR_PRIx
+                      " v=0x%x\n", __func__, addr, val32);
+    }
+}
+
+static const MemoryRegionOps sifive_u_otp_ops = {
+    .read = sifive_u_otp_read,
+    .write = sifive_u_otp_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4
+    }
+};
+
+static Property sifive_u_otp_properties[] = {
+    DEFINE_PROP_UINT32("serial", SiFiveUOTPState, serial, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void sifive_u_otp_realize(DeviceState *dev, Error **errp)
+{
+    SiFiveUOTPState *s = SIFIVE_U_OTP(dev);
+
+    memory_region_init_io(&s->mmio, OBJECT(dev), &sifive_u_otp_ops, s,
+                          TYPE_SIFIVE_U_OTP, SIFIVE_U_OTP_REG_SIZE);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
+}
+
+static void sifive_u_otp_reset(DeviceState *dev)
+{
+    SiFiveUOTPState *s = SIFIVE_U_OTP(dev);
+
+    /* Initialize all fuses' initial value to 0xFFs */
+    memset(s->fuse, 0xff, sizeof(s->fuse));
+
+    /* Make a valid content of serial number */
+    s->fuse[SIFIVE_U_OTP_SERIAL_ADDR] = s->serial;
+    s->fuse[SIFIVE_U_OTP_SERIAL_ADDR + 1] = ~(s->serial);
+}
+
+static void sifive_u_otp_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->props = sifive_u_otp_properties;
+    dc->realize = sifive_u_otp_realize;
+    dc->reset = sifive_u_otp_reset;
+}
+
+static const TypeInfo sifive_u_otp_info = {
+    .name          = TYPE_SIFIVE_U_OTP,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(SiFiveUOTPState),
+    .class_init    = sifive_u_otp_class_init,
+};
+
+static void sifive_u_otp_register_types(void)
+{
+    type_register_static(&sifive_u_otp_info);
+}
+
+type_init(sifive_u_otp_register_types)