/*
 * This software is experimental and a work in progress.
 * Under no circumstances should these files be used in relation to any critical system(s).
 * Use of these files is at your own risk.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and
 * https://github.com/leaflabs/libmaple
 *
 * Modifications for QMK and STM32F303 by Yiancar
 */

#if defined(EEPROM_EMU_STM32F303xC)
    #define STM32F303xC
    #include "stm32f3xx.h"
#elif defined(EEPROM_EMU_STM32F103xB)
    #define STM32F103xB
    #include "stm32f1xx.h"
#else
    #error "not implemented."
#endif

#include "flash_stm32.h"

#if defined(EEPROM_EMU_STM32F103xB)
    #define FLASH_SR_WRPERR FLASH_SR_WRPRTERR
#endif

/* Delay definition */
#define EraseTimeout        ((uint32_t)0x00000FFF)
#define ProgramTimeout      ((uint32_t)0x0000001F)

#define ASSERT(exp) (void)((0))

/**
  * @brief  Inserts a time delay.
  * @param  None
  * @retval None
  */
static void delay(void)
{
    __IO uint32_t i = 0;
    for(i = 0xFF; i != 0; i--) { }
}

/**
  * @brief  Returns the FLASH Status.
  * @param  None
  * @retval FLASH Status: The returned value can be: FLASH_BUSY, FLASH_ERROR_PG,
  *   FLASH_ERROR_WRP or FLASH_COMPLETE
  */
FLASH_Status FLASH_GetStatus(void)
{
    if ((FLASH->SR & FLASH_SR_BSY) == FLASH_SR_BSY)
        return FLASH_BUSY;

    if ((FLASH->SR & FLASH_SR_PGERR) != 0)
        return FLASH_ERROR_PG;

    if ((FLASH->SR & FLASH_SR_WRPERR) != 0 )
        return FLASH_ERROR_WRP;

    if ((FLASH->SR & FLASH_OBR_OPTERR) != 0 )
        return FLASH_ERROR_OPT;

    return FLASH_COMPLETE;
}

/**
  * @brief  Waits for a Flash operation to complete or a TIMEOUT to occur.
  * @param  Timeout: FLASH progamming Timeout
  * @retval FLASH Status: The returned value can be: FLASH_ERROR_PG,
  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT.
  */
FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout)
{
    FLASH_Status status;

    /* Check for the Flash Status */
    status = FLASH_GetStatus();
    /* Wait for a Flash operation to complete or a TIMEOUT to occur */
    while ((status == FLASH_BUSY) && (Timeout != 0x00))
    {
        delay();
        status = FLASH_GetStatus();
        Timeout--;
    }
    if (Timeout == 0)
        status = FLASH_TIMEOUT;
    /* Return the operation status */
    return status;
}

/**
  * @brief  Erases a specified FLASH page.
  * @param  Page_Address: The page address to be erased.
  * @retval FLASH Status: The returned value can be: FLASH_BUSY, FLASH_ERROR_PG,
  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT.
  */
FLASH_Status FLASH_ErasePage(uint32_t Page_Address)
{
    FLASH_Status status = FLASH_COMPLETE;
    /* Check the parameters */
    ASSERT(IS_FLASH_ADDRESS(Page_Address));
    /* Wait for last operation to be completed */
    status = FLASH_WaitForLastOperation(EraseTimeout);

    if(status == FLASH_COMPLETE)
    {
        /* if the previous operation is completed, proceed to erase the page */
        FLASH->CR |= FLASH_CR_PER;
        FLASH->AR = Page_Address;
        FLASH->CR |= FLASH_CR_STRT;

        /* Wait for last operation to be completed */
        status = FLASH_WaitForLastOperation(EraseTimeout);
        if(status != FLASH_TIMEOUT)
        {
            /* if the erase operation is completed, disable the PER Bit */
            FLASH->CR &= ~FLASH_CR_PER;
        }
        FLASH->SR = (FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPERR);
    }
    /* Return the Erase Status */
    return status;
}

/**
  * @brief  Programs a half word at a specified address.
  * @param  Address: specifies the address to be programmed.
  * @param  Data: specifies the data to be programmed.
  * @retval FLASH Status: The returned value can be: FLASH_ERROR_PG,
  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT.
  */
FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data)
{
    FLASH_Status status = FLASH_BAD_ADDRESS;

    if (IS_FLASH_ADDRESS(Address))
    {
        /* Wait for last operation to be completed */
        status = FLASH_WaitForLastOperation(ProgramTimeout);
        if(status == FLASH_COMPLETE)
        {
            /* if the previous operation is completed, proceed to program the new data */
            FLASH->CR |= FLASH_CR_PG;
            *(__IO uint16_t*)Address = Data;
            /* Wait for last operation to be completed */
            status = FLASH_WaitForLastOperation(ProgramTimeout);
            if(status != FLASH_TIMEOUT)
            {
                /* if the program operation is completed, disable the PG Bit */
                FLASH->CR &= ~FLASH_CR_PG;
            }
            FLASH->SR = (FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPERR);
        }
    }
    return status;
}

/**
  * @brief  Unlocks the FLASH Program Erase Controller.
  * @param  None
  * @retval None
  */
void FLASH_Unlock(void)
{
    /* Authorize the FPEC Access */
    FLASH->KEYR = FLASH_KEY1;
    FLASH->KEYR = FLASH_KEY2;
}

/**
  * @brief  Locks the FLASH Program Erase Controller.
  * @param  None
  * @retval None
  */
void FLASH_Lock(void)
{
    /* Set the Lock Bit to lock the FPEC and the FCR */
    FLASH->CR |= FLASH_CR_LOCK;
}

/**
  * @brief  Clears the FLASH's pending flags.
  * @param  FLASH_FLAG: specifies the FLASH flags to clear.
  *   This parameter can be any combination of the following values:
  *     @arg FLASH_FLAG_PGERR: FLASH Programming error flag flag
  *     @arg FLASH_FLAG_WRPERR: FLASH Write protected error flag
  *     @arg FLASH_FLAG_EOP: FLASH End of Programming flag                
  * @retval None
  */
void FLASH_ClearFlag(uint32_t FLASH_FLAG)
{
    /* Clear the flags */
    FLASH->SR = FLASH_FLAG;
}