1 files changed, 94 insertions, 1 deletions

diff --git a/hw/misc/sifive_u_otp.c b/hw/misc/sifive_u_otp.c
index c2f3c8e..6006637 100644
--- a/hw/misc/sifive_u_otp.c
+++ b/hw/misc/sifive_u_otp.c
@@ -19,11 +19,22 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "hw/qdev-properties.h"
 #include "hw/sysbus.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "hw/misc/sifive_u_otp.h"
+#include "sysemu/blockdev.h"
+#include "sysemu/block-backend.h"
+
+#define WRITTEN_BIT_ON 0x1
+
+#define SET_FUSEARRAY_BIT(map, i, off, bit)    \
+    map[i] = bit ? (map[i] | bit << off) : (map[i] & ~(0x1 << off))
+
+#define GET_FUSEARRAY_BIT(map, i, off)    \
+    ((map[i] >> off) & 0x1)
 
 static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr, unsigned int size)
 {
@@ -46,6 +57,16 @@ 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)) {
+
+            /* read from backend */
+            if (s->blk) {
+                int32_t buf;
+
+                blk_pread(s->blk, s->pa * SIFIVE_U_OTP_FUSE_WORD, &buf,
+                          SIFIVE_U_OTP_FUSE_WORD);
+                return buf;
+            }
+
             return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
         } else {
             return 0xff;
@@ -123,7 +144,30 @@ static void sifive_u_otp_write(void *opaque, hwaddr addr,
         s->ptrim = val32;
         break;
     case SIFIVE_U_OTP_PWE:
-        s->pwe = val32;
+        s->pwe = val32 & SIFIVE_U_OTP_PWE_EN;
+
+        /* PWE is enabled. Ignore PAS=1 (no redundancy cell) */
+        if (s->pwe && !s->pas) {
+            if (GET_FUSEARRAY_BIT(s->fuse_wo, s->pa, s->paio)) {
+                qemu_log_mask(LOG_GUEST_ERROR,
+                              "write once error: idx<%u>, bit<%u>\n",
+                              s->pa, s->paio);
+                break;
+            }
+
+            /* write bit data */
+            SET_FUSEARRAY_BIT(s->fuse, s->pa, s->paio, s->pdin);
+
+            /* write to backend */
+            if (s->blk) {
+                blk_pwrite(s->blk, s->pa * SIFIVE_U_OTP_FUSE_WORD,
+                           &s->fuse[s->pa], SIFIVE_U_OTP_FUSE_WORD, 0);
+            }
+
+            /* update written bit */
+            SET_FUSEARRAY_BIT(s->fuse_wo, s->pa, s->paio, WRITTEN_BIT_ON);
+        }
+
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%" HWADDR_PRIx
@@ -143,16 +187,48 @@ static const MemoryRegionOps sifive_u_otp_ops = {
 
 static Property sifive_u_otp_properties[] = {
     DEFINE_PROP_UINT32("serial", SiFiveUOTPState, serial, 0),
+    DEFINE_PROP_DRIVE("drive", SiFiveUOTPState, blk),
     DEFINE_PROP_END_OF_LIST(),
 };
 
 static void sifive_u_otp_realize(DeviceState *dev, Error **errp)
 {
     SiFiveUOTPState *s = SIFIVE_U_OTP(dev);
+    DriveInfo *dinfo;
 
     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);
+
+    dinfo = drive_get_next(IF_NONE);
+    if (dinfo) {
+        int ret;
+        uint64_t perm;
+        int filesize;
+        BlockBackend *blk;
+
+        blk = blk_by_legacy_dinfo(dinfo);
+        filesize = SIFIVE_U_OTP_NUM_FUSES * SIFIVE_U_OTP_FUSE_WORD;
+        if (blk_getlength(blk) < filesize) {
+            error_setg(errp, "OTP drive size < 16K");
+            return;
+        }
+
+        qdev_prop_set_drive_err(dev, "drive", blk, errp);
+
+        if (s->blk) {
+            perm = BLK_PERM_CONSISTENT_READ |
+                   (blk_is_read_only(s->blk) ? 0 : BLK_PERM_WRITE);
+            ret = blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp);
+            if (ret < 0) {
+                return;
+            }
+
+            if (blk_pread(s->blk, 0, s->fuse, filesize) != filesize) {
+                error_setg(errp, "failed to read the initial flash content");
+            }
+        }
+    }
 }
 
 static void sifive_u_otp_reset(DeviceState *dev)
@@ -165,6 +241,23 @@ static void sifive_u_otp_reset(DeviceState *dev)
     /* 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);
+
+    if (s->blk) {
+        /* Put serial number to backend as well*/
+        uint32_t serial_data;
+        int index = SIFIVE_U_OTP_SERIAL_ADDR;
+
+        serial_data = s->serial;
+        blk_pwrite(s->blk, index * SIFIVE_U_OTP_FUSE_WORD,
+                   &serial_data, SIFIVE_U_OTP_FUSE_WORD, 0);
+
+        serial_data = ~(s->serial);
+        blk_pwrite(s->blk, (index + 1) * SIFIVE_U_OTP_FUSE_WORD,
+                   &serial_data, SIFIVE_U_OTP_FUSE_WORD, 0);
+    }
+
+    /* Initialize write-once map */
+    memset(s->fuse_wo, 0x00, sizeof(s->fuse_wo));
 }
 
 static void sifive_u_otp_class_init(ObjectClass *klass, void *data)