From 0d09f6d788bb4efd37a447b5276a4bf93871421b Mon Sep 17 00:00:00 2001
From: bcostm <bco.stm@gmail.com>
Date: Tue, 12 Dec 2017 16:52:32 +0100
Subject: [PATCH] STM32F3: add Flash api

---
 .../TARGET_STM32F3/common_objects.h           |   7 +
 targets/TARGET_STM/TARGET_STM32F3/flash_api.c | 173 ++++++++++++++++++
 2 files changed, 180 insertions(+)
 create mode 100644 targets/TARGET_STM/TARGET_STM32F3/flash_api.c

diff --git a/targets/TARGET_STM/TARGET_STM32F3/common_objects.h b/targets/TARGET_STM/TARGET_STM32F3/common_objects.h
index ba731890ce..590b60d94c 100644
--- a/targets/TARGET_STM/TARGET_STM32F3/common_objects.h
+++ b/targets/TARGET_STM/TARGET_STM32F3/common_objects.h
@@ -132,6 +132,13 @@ struct can_s {
 };
 #endif
 
+#if DEVICE_FLASH
+struct flash_s {
+    /*  nothing to be stored for now */
+    uint32_t dummy;
+};
+#endif
+
 #include "gpio_object.h"
 
 #ifdef __cplusplus
diff --git a/targets/TARGET_STM/TARGET_STM32F3/flash_api.c b/targets/TARGET_STM/TARGET_STM32F3/flash_api.c
new file mode 100644
index 0000000000..459294d045
--- /dev/null
+++ b/targets/TARGET_STM/TARGET_STM32F3/flash_api.c
@@ -0,0 +1,173 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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 "flash_api.h"
+#include "mbed_critical.h"
+
+#if DEVICE_FLASH
+#include "mbed_assert.h"
+#include "cmsis.h"
+
+#define NUM_PAGES_IN_SECTOR  (1U)
+#define FLASH_SIZE           (uint32_t)(*((uint16_t *)FLASHSIZE_BASE) * 1024U)
+
+int32_t flash_init(flash_t *obj)
+{
+    return 0;
+}
+
+int32_t flash_free(flash_t *obj)
+{
+    return 0;
+}
+
+static int32_t flash_unlock(void)
+{
+    /* Allow Access to Flash control registers and user Falsh */
+    if (HAL_FLASH_Unlock()) {
+        return -1;
+    } else {
+        return 0;
+    }
+}
+
+static int32_t flash_lock(void)
+{
+    /* Disable the Flash option control register access (recommended to protect
+    the option Bytes against possible unwanted operations) */
+    if (HAL_FLASH_Lock()) {
+        return -1;
+    } else {
+        return 0;
+    }
+}
+
+int32_t flash_erase_sector(flash_t *obj, uint32_t address)
+{
+    uint32_t PAGEError = 0;
+    FLASH_EraseInitTypeDef EraseInitStruct;
+    int32_t status = 0;
+
+    if (!(IS_FLASH_PROGRAM_ADDRESS(address))) {
+        return -1;
+    }
+
+    if (flash_unlock() != HAL_OK) {
+        return -1;
+    }
+
+    __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_WRPERR);
+    /* MBED HAL erases 1 sector at a time */
+    /* Fill EraseInit structure*/
+    EraseInitStruct.TypeErase   = FLASH_TYPEERASE_PAGES;
+    EraseInitStruct.PageAddress = address;
+    EraseInitStruct.NbPages     = NUM_PAGES_IN_SECTOR;
+
+    /* Note: If an erase operation in Flash memory also concerns data in the data or instruction cache,
+     you have to make sure that these data are rewritten before they are accessed during code
+     execution. If this cannot be done safely, it is recommended to flush the caches by setting the
+     DCRST and ICRST bits in the FLASH_CR register. */
+
+    if (HAL_FLASHEx_Erase(&EraseInitStruct, &PAGEError) != HAL_OK) {
+        status = -1;
+    }
+
+    flash_lock();
+
+    return status;
+
+}
+
+int32_t flash_program_page(flash_t *obj, uint32_t address,
+        const uint8_t *data, uint32_t size)
+{
+    uint32_t StartAddress = 0;
+    int32_t status = 0;
+
+    if (!(IS_FLASH_PROGRAM_ADDRESS(address))) {
+        return -1;
+    }
+
+    if ((size % 4) != 0) {
+        /* F3 flash devices can only be programmed 32bits/4 bytes at a time */
+        return -1;
+    }
+
+    if (flash_unlock() != HAL_OK) {
+        return -1;
+    }
+
+    /* Program the user Flash area word by word */
+    StartAddress = address;
+
+    /*  HW needs an aligned address to program flash, which data
+     *  parameters doesn't ensure  */
+    if ((uint32_t) data % 4 != 0) {
+        volatile uint32_t data32;
+        while (address < (StartAddress + size) && (status == 0)) {
+            for (uint8_t i =0; i < 4; i++) {
+                *(((uint8_t *) &data32) + i) = *(data + i);
+            }
+
+            if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, address, data32) == HAL_OK) {
+                address = address + 4;
+                data = data + 4;
+            } else {
+                status = -1;
+            }
+        }
+    } else { /*  case where data is aligned, so let's avoid any copy */
+        while ((address < (StartAddress + size)) && (status == 0)) {
+            if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, address, *((uint32_t*) data)) == HAL_OK) {
+                address = address + 4;
+                data = data + 4;
+            } else {
+                status = -1;
+            }
+        }
+    }
+
+    flash_lock();
+
+    return status;
+}
+
+uint32_t flash_get_sector_size(const flash_t *obj, uint32_t address) 
+{
+    if (!(IS_FLASH_PROGRAM_ADDRESS(address))) {
+        return MBED_FLASH_INVALID_SIZE;
+    } else {
+        return (NUM_PAGES_IN_SECTOR * FLASH_PAGE_SIZE);
+    }
+}
+
+uint32_t flash_get_page_size(const flash_t *obj)
+{
+    /* Page size is the minimum programmable size, which is 4 bytes */
+    return 4;
+}
+
+uint32_t flash_get_start_address(const flash_t *obj) 
+{
+    return FLASH_BASE;
+}
+
+uint32_t flash_get_size(const flash_t *obj) 
+{
+    return FLASH_SIZE;
+}
+
+#endif