Import of the watch repository from Pebble

platform/tintin/boot/src/drivers/stm32_common/otp.c

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "drivers/otp.h"
+
+#include "stm32f2xx_flash.h"
+
+#include <stdint.h>
+#include <stdbool.h>
+
+// See page 53 of STM Reference Manual RM0033:
+#define OTP_SLOTS_BASE_ADDR (0x1FFF7800)
+#define OTP_LOCKS_BASE_ADDR (0x1FFF7A00)
+
+//! Each OTP slot is 32 bytes. There are 16 slots: [0-15]
+char * otp_get_slot(const uint8_t index) {
+  return (char * const) (OTP_SLOTS_BASE_ADDR + (32 * index));
+}
+
+uint8_t * otp_get_lock(const uint8_t index) {
+  return (uint8_t * const) (OTP_LOCKS_BASE_ADDR + index);
+}
+
+bool otp_is_locked(const uint8_t index) {
+  return (*otp_get_lock(index) == 0);
+}