From bbf77c4ab079451d9630bf4e9b2d654b842ec982 Mon Sep 17 00:00:00 2001
From: silseva <silseva@fastwebnet.it>
Date: Mon, 8 Nov 2021 17:10:00 +0100
Subject: [PATCH] Simple driver for erase and write of MCU's internal flash

---
 platform/drivers/NVM/mcuFlash.h     | 49 +++++++++++++++++
 platform/drivers/NVM/mcuFlash_MDx.c | 82 +++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 platform/drivers/NVM/mcuFlash.h
 create mode 100644 platform/drivers/NVM/mcuFlash_MDx.c

diff --git a/platform/drivers/NVM/mcuFlash.h b/platform/drivers/NVM/mcuFlash.h
new file mode 100644
index 00000000..fbfceefe
--- /dev/null
+++ b/platform/drivers/NVM/mcuFlash.h
@@ -0,0 +1,49 @@
+/***************************************************************************
+ *   Copyright (C) 2021 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#ifndef MCUFLASH_H
+#define MCUFLASH_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * Driver for MCU's internal flash management, allowing for sector erase and data
+ * writing.
+ */
+
+/**
+ * Erase one sector of the MCU flash memory.
+ *
+ * @param secNum: sector number.
+ * @return true for successful erase, false otherwise.
+ */
+bool mcuFlash_eraseSector(const uint8_t secNum);
+
+/**
+ * Write data to the MCU flash memory.
+ *
+ * @param address: starting address for the write operation.
+ * @param data: data to be written.
+ * @param len: data length.
+ */
+void mcuFlash_write(const uint32_t address, const void *data, const size_t len);
+
+#endif /* MCUFLASH_H */
\ No newline at end of file
diff --git a/platform/drivers/NVM/mcuFlash_MDx.c b/platform/drivers/NVM/mcuFlash_MDx.c
new file mode 100644
index 00000000..5df510ab
--- /dev/null
+++ b/platform/drivers/NVM/mcuFlash_MDx.c
@@ -0,0 +1,82 @@
+/***************************************************************************
+ *   Copyright (C) 2021 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include "mcuFlash.h"
+
+inline bool unlock()
+{
+	// Flash already unlocked
+	if((FLASH->CR & FLASH_CR_LOCK) == 0)
+	{
+		return true;
+	}
+
+	FLASH->KEYR = 0x45670123;
+	FLASH->KEYR = 0xCDEF89AB;
+
+	// Succesful unlock
+	if((FLASH->CR & FLASH_CR_LOCK) == 0)
+	{
+		return true;
+	}
+
+	return false;
+}
+
+bool mcuFlash_eraseSector(const uint8_t secNum)
+{
+	if(secNum > 11) return false;
+	if(unlock() == false) return false;
+
+	// Flash busy, wait until previous operation finishes
+	while((FLASH->SR & FLASH_SR_BSY) != 0) ;
+
+	FLASH->CR |= FLASH_CR_PSIZE_1	// 32-bit program parallelism
+	          |  (secNum << 3)		// Sector number
+	          |  FLASH_CR_SER		// Sector erase
+	          |  FLASH_CR_STRT;     // Start erase
+
+	// Wait until erase ends
+	while((FLASH->SR & FLASH_SR_BSY) != 0) ;
+
+	return true;
+}
+
+void mcuFlash_write(const uint32_t address, const void *data, const size_t len)
+{
+	if((data == NULL) || (len == 0)) return;
+
+	// Flash busy, wait until previous operation finishes
+	while((FLASH->SR & FLASH_SR_BSY) != 0) ;
+
+	// Request programming with 8-bit parallelism
+	FLASH->CR = FLASH_CR_PG;
+
+	const uint8_t *buf = ((uint8_t *) data);
+	const uint8_t *mem = ((uint8_t *) address);
+	for(size_t i = 0; i < len; i++)
+	{
+		*mem = buf[i];
+		mem++;
+	}
+
+	// Wait until the end of the write operation
+	while((FLASH->SR & FLASH_SR_BSY) != 0) ;
+}
\ No newline at end of file