/*
 * flash.c
 *
 *  Created on: Apr 12, 2024
 *  Author: Francesco Gritti
 */

#include "flash.h"
#include "ftypes.h"





void flash_unlock (void) {

  if ((FLASH->CR & FLASH_CR_LOCK) != 0) {
    FLASH->KEYR = FLASH_KEY1;
    FLASH->KEYR = FLASH_KEY2;
  }
}

void flash_lock (void) {
  FLASH->CR |= FLASH_CR_LOCK;
}




void flash_erase_page (u32 page) {
	// make sure no operation is ongoing
	flash_wait_last_op();

	FLASH->CR |= FLASH_CR_PER;
	FLASH->AR = page;
	FLASH->CR |= FLASH_CR_STRT;

	flash_wait_last_op ();

	FLASH->CR &= ~FLASH_CR_PER;
}


// write data in LITTLE ENDIAN format
u8 flash_program_word (u32 address, u32 data) {

	flash_program_hword (address, (u16)data);
	flash_program_hword (address +2, (u16)(data>>16));

	u32 read_data =  *(volatile u32*) (address);
    return (read_data == data);
}

u8 flash_program_hword (u32 address, u16 data) {

  flash_wait_last_op ();

  FLASH->CR |= FLASH_CR_PG;

  // write the byte into FLASH as if it was with a normal memory address
  *(volatile u16*) (address) = data;

  flash_wait_last_op ();
  FLASH->CR &= ~FLASH_CR_PG;


  u16 read_data =  *(volatile u16*) (address);
  return (read_data == data);
}



void flash_wait_last_op () {
  // wait for operation to complete
  while((FLASH->SR & FLASH_SR_BSY) != 0);

  // clear end of operation flag if it was set
  if ((FLASH->SR & FLASH_SR_EOP) != 0)
    FLASH->SR |= FLASH_SR_EOP;
}