Support for STM32U5 option bytes read/write

Author: Nightwalker-87

config/chips/U575_U585.chip

@@ -12,5 +12,5 @@ bootrom_size 0x10000         // 64 KB
 option_base 0x0
 option_size 0x0
 flags swo dualbank
-otp_base 0x0BFA0000
+otp_base 0x0bfa0000
 otp_size 0x200 

config/chips/U59x_U5Ax.chip

@@ -9,6 +9,6 @@ flash_pagesize 0x2000        // 8 KB
 sram_size 0x274800           // 2514 KB
 bootrom_base 0x0bf90000
 bootrom_size 0x8000          // 32 KB
-option_base 0x0
-option_size 0x0
+option_base 0x40022040
+option_size 0x04
 flags swo dualbank

src/stlink-lib/option_bytes.c

@@ -757,6 +757,58 @@ static int32_t stlink_write_option_bytes_wb(stlink_t *sl, stm32_addr_t addr, uin
   return (ret);
 }
 
+/**
+ * Write option bytes L5
+ * @param sl
+ * @param addr of the memory mapped option bytes
+ * @param base option bytes
+ * @param len of option bytes
+ * @return 0 on success, -ve on failure.
+ */
+static int32_t stlink_write_option_bytes_l5(stlink_t *sl, stm32_addr_t addr,
+                                            uint8_t *base, uint32_t len) {
+  /* Write options bytes */
+  uint32_t val;
+  int32_t ret = 0;
+  (void)len;
+  uint32_t data;
+
+  clear_flash_error(sl);
+
+  while (len != 0) {
+    write_uint32((unsigned char *)&data,
+                 *(uint32_t *)(base)); // write options bytes
+
+    WLOG("Writing option bytes %#10x to %#10x\n", data, addr);
+    stlink_write_debug32(sl, addr, data);
+    wait_flash_busy(sl);
+
+    if ((ret = check_flash_error(sl))) {
+      break;
+    }
+
+    len -= 4;
+    addr += 4;
+    base += 4;
+  }
+
+  // Set Options Start bit
+  stlink_read_debug32(sl, STM32_FLASH_L5_NSCR, &val);
+  val |= (1 << STM32_FLASH_L5_NSCR_NSOPTSTRT);
+  stlink_write_debug32(sl, STM32_FLASH_L5_NSCR, val);
+
+  wait_flash_busy(sl);
+
+  ret = check_flash_error(sl);
+
+  // Reload options
+  stlink_read_debug32(sl, STM32_FLASH_L5_NSCR, &val);
+  val |= (1 << STM32_FLASH_L5_NSCR_OBL_LAUNCH);
+  stlink_write_debug32(sl, STM32_FLASH_L5_NSCR, val);
+
+  return (ret);
+}
+
 /**
  * Read option control register WB
  * @param sl
@@ -880,6 +932,9 @@ int32_t stlink_write_option_bytes(stlink_t *sl, stm32_addr_t addr, uint8_t *base
   case STM32_FLASH_TYPE_WB_WL:
     ret = stlink_write_option_bytes_wb(sl, addr, base, len);
     break;
+  case STM32_FLASH_TYPE_L5_U5_H5:
+    ret = stlink_write_option_bytes_l5(sl, addr, base, len);
+    break;
   default:
     ELOG("Option bytes writing is currently not implemented for connected chip\n");
     break;