[RFC PATCH v2 1/2] hw/riscv: sifive_u: Add file-backed OTP.

[Green Wan <green.wan@sifive.com>]

Add a file-backed implementation for OTP of sifive_u machine. The
machine property for file-backed is disabled in default. Do file
open, mmap and close for every OTP read/write in case keep the
update-to-date snapshot of OTP.

Signed-off-by: Green Wan <green.wan@sifive.com>
---
 hw/riscv/sifive_u.c             | 26 +++++++++++
 hw/riscv/sifive_u_otp.c         | 83 +++++++++++++++++++++++++++++++++
 include/hw/riscv/sifive_u.h     |  2 +
 include/hw/riscv/sifive_u_otp.h |  1 +
 4 files changed, 112 insertions(+)

diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index e5682c38a9..c818496918 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -87,6 +87,7 @@ static const struct MemmapEntry {
 };
 
 #define OTP_SERIAL          1
+#define OTP_FILE            "NULL"
 #define GEM_REVISION        0x10070109
 
 static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
@@ -387,6 +388,8 @@ static void sifive_u_machine_init(MachineState *machine)
     object_initialize_child(OBJECT(machine), "soc", &s->soc, TYPE_RISCV_U_SOC);
     object_property_set_uint(OBJECT(&s->soc), "serial", s->serial,
                              &error_abort);
+    object_property_set_str(OBJECT(&s->soc), "otp-file", s->otp_file,
+                             &error_abort);
     qdev_realize(DEVICE(&s->soc), NULL, &error_abort);
 
     /* register RAM */
@@ -526,6 +529,21 @@ static void sifive_u_machine_set_uint32_prop(Object *obj, Visitor *v,
     visit_type_uint32(v, name, (uint32_t *)opaque, errp);
 }
 
+static void sifive_u_machine_get_str_prop(Object *obj, Visitor *v,
+                                             const char *name, void *opaque,
+                                             Error **errp)
+{
+    visit_type_str(v, name, (char **)opaque, errp);
+}
+
+static void sifive_u_machine_set_str_prop(Object *obj, Visitor *v,
+                                             const char *name, void *opaque,
+                                             Error **errp)
+{
+    visit_type_str(v, name, (char **)opaque, errp);
+}
+
+
 static void sifive_u_machine_instance_init(Object *obj)
 {
     SiFiveUState *s = RISCV_U_MACHINE(obj);
@@ -551,6 +569,12 @@ static void sifive_u_machine_instance_init(Object *obj)
                         sifive_u_machine_get_uint32_prop,
                         sifive_u_machine_set_uint32_prop, NULL, &s->serial);
     object_property_set_description(obj, "serial", "Board serial number");
+
+    s->otp_file = (char *)OTP_FILE;
+    object_property_add(obj, "otp-file", "string",
+                        sifive_u_machine_get_str_prop,
+                        sifive_u_machine_set_str_prop, NULL, &s->otp_file);
+    object_property_set_description(obj, "otp-file", "file-backed otp file");
 }
 
 static void sifive_u_machine_class_init(ObjectClass *oc, void *data)
@@ -709,6 +733,7 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
     }
 
     qdev_prop_set_uint32(DEVICE(&s->otp), "serial", s->serial);
+    qdev_prop_set_string(DEVICE(&s->otp), "otp-file", s->otp_file);
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->otp), errp)) {
         return;
     }
@@ -737,6 +762,7 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
 
 static Property sifive_u_soc_props[] = {
     DEFINE_PROP_UINT32("serial", SiFiveUSoCState, serial, OTP_SERIAL),
+    DEFINE_PROP_STRING("otp-file", SiFiveUSoCState, otp_file),
     DEFINE_PROP_END_OF_LIST()
 };
 
diff --git a/hw/riscv/sifive_u_otp.c b/hw/riscv/sifive_u_otp.c
index f6ecbaa2ca..e359f30fdb 100644
--- a/hw/riscv/sifive_u_otp.c
+++ b/hw/riscv/sifive_u_otp.c
@@ -24,6 +24,62 @@
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "hw/riscv/sifive_u_otp.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <string.h>
+
+#define TRACE_PREFIX            "FU540_OTP: "
+#define SIFIVE_FU540_OTP_SIZE   (SIFIVE_U_OTP_NUM_FUSES * 4)
+
+static int32_t sifive_u_otp_backed_open(const char *filename, int32_t *fd,
+                                        uint32_t **map)
+{
+    /* open and mmap OTP image file */
+    if (filename && strcmp(filename, "NULL") != 0) {
+        *fd = open(filename, O_RDWR);
+
+        if (*fd < 0) {
+            qemu_log_mask(LOG_TRACE,
+                          TRACE_PREFIX "Warning: can't open otp file<%s>\n",
+                          filename);
+            return -1;
+        } else {
+
+            *map = (unsigned int *)mmap(0,
+                                         SIFIVE_FU540_OTP_SIZE,
+                                         PROT_READ | PROT_WRITE | PROT_EXEC,
+                                         MAP_FILE | MAP_SHARED,
+                                         *fd,
+                                         0);
+
+            if (*map == MAP_FAILED) {
+                qemu_log_mask(LOG_TRACE,
+                              TRACE_PREFIX "Warning: can't mmap otp file<%s>\n",
+                              filename);
+                close(*fd);
+                return -2;
+            }
+        }
+    } else {
+        /* filename is 'NULL' */
+        return -3;
+    }
+
+    return 0;
+}
+
+static int32_t sifive_u_otp_backed_close(int fd, unsigned int *map)
+{
+    munmap(map, SIFIVE_FU540_OTP_SIZE);
+    close(fd);
+
+    return 0;
+}
 
 static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr, unsigned int size)
 {
@@ -46,6 +102,20 @@ static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr, unsigned int size)
         if ((s->pce & SIFIVE_U_OTP_PCE_EN) &&
             (s->pdstb & SIFIVE_U_OTP_PDSTB_EN) &&
             (s->ptrim & SIFIVE_U_OTP_PTRIM_EN)) {
+
+            int32_t fd;
+            uint32_t *map;
+            uint64_t val;
+
+            /* open and mmap OTP image file */
+            if (0 == sifive_u_otp_backed_open(s->otp_file, &fd, &map)) {
+                val = (uint64_t)(map[s->pa]);
+
+                /* close and unmmap */
+                sifive_u_otp_backed_close(fd, map);
+                return val;
+            }
+
             return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
         } else {
             return 0xff;
@@ -78,6 +148,8 @@ static void sifive_u_otp_write(void *opaque, hwaddr addr,
 {
     SiFiveUOTPState *s = opaque;
     uint32_t val32 = (uint32_t)val64;
+    int32_t fd;
+    uint32_t *map;
 
     switch (addr) {
     case SIFIVE_U_OTP_PA:
@@ -123,6 +195,16 @@ static void sifive_u_otp_write(void *opaque, hwaddr addr,
         s->ptrim = val32;
         break;
     case SIFIVE_U_OTP_PWE:
+        /* open and mmap OTP image file */
+        if (0 == sifive_u_otp_backed_open(s->otp_file, &fd, &map)) {
+            /* store value */
+            map[s->pa] &= ~(s->pdin << s->paio);
+            map[s->pa] |= (s->pdin << s->paio);
+
+            /* close and unmmap */
+            sifive_u_otp_backed_close(fd, map);
+        }
+
         s->pwe = val32;
         break;
     default:
@@ -143,6 +225,7 @@ static const MemoryRegionOps sifive_u_otp_ops = {
 
 static Property sifive_u_otp_properties[] = {
     DEFINE_PROP_UINT32("serial", SiFiveUOTPState, serial, 0),
+    DEFINE_PROP_STRING("otp-file", SiFiveUOTPState, otp_file),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h
index aba4d0181f..966723da1d 100644
--- a/include/hw/riscv/sifive_u.h
+++ b/include/hw/riscv/sifive_u.h
@@ -46,6 +46,7 @@ typedef struct SiFiveUSoCState {
     CadenceGEMState gem;
 
     uint32_t serial;
+    char *otp_file;
 } SiFiveUSoCState;
 
 #define TYPE_RISCV_U_MACHINE MACHINE_TYPE_NAME("sifive_u")
@@ -65,6 +66,7 @@ typedef struct SiFiveUState {
     bool start_in_flash;
     uint32_t msel;
     uint32_t serial;
+    char *otp_file;
 } SiFiveUState;
 
 enum {
diff --git a/include/hw/riscv/sifive_u_otp.h b/include/hw/riscv/sifive_u_otp.h
index 639297564a..f3d71ce82d 100644
--- a/include/hw/riscv/sifive_u_otp.h
+++ b/include/hw/riscv/sifive_u_otp.h
@@ -75,6 +75,7 @@ typedef struct SiFiveUOTPState {
     uint32_t fuse[SIFIVE_U_OTP_NUM_FUSES];
     /* config */
     uint32_t serial;
+    char *otp_file;
 } SiFiveUOTPState;
 
 #endif /* HW_SIFIVE_U_OTP_H */
-- 
2.17.1