eeprom.c

/**
 ******************************************************************************
 * @file    STM32F3xx_EEPROM_Emulation/src/eeprom.c
 * @author  MCD Application Team
 * @version V1.0.0
 * @date    02-October-2012
 * @brief   This file provides all the EEPROM emulation firmware functions.
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>
 *
 * Licensed under MCD-ST Liberty SW License Agreement V2, (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.st.com/software_license_agreement_liberty_v2
 *
 * 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.
 *
 ******************************************************************************
 */ 

/* Includes ------------------------------------------------------------------*/
#include "eeprom.h"

/** @addtogroup EEPROM_Emulation
 * @{
 */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/

/* Global variable used to store variable value in read sequence */
uint16_t DataVar = 0;

/* Virtual address defined by the user: 0xFFFF value is prohibited */
extern uint16_t VirtAddVarTab[NB_OF_VAR];

/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
static FLASH_Status EE_Format(void);
static uint16_t EE_VerifyPageFullWriteVariable(uint16_t VirtAddress, uint16_t Data);
static uint16_t EE_PageTransfer(uint16_t VirtAddress, uint16_t Data);
static uint16_t EE_FindValidPage(uint8_t Operation);

/**
 * @brief  Restore the pages to a known good state in case of page's status
 *   corruption after a power loss.
 * @param  None.
 * @retval - Flash error code: on write Flash error
 *         - FLASH_COMPLETE: on success
 */
uint16_t EE_Init(void)
{
    uint16_t PageStatus0 = 6, PageStatus1 = 6;
    uint16_t VarIdx = 0;
    uint16_t EepromStatus = 0, ReadStatus = 0;
    int16_t x = -1;
    uint16_t  FlashStatus;

    /* Get Page0 status */
    PageStatus0 = (*(__IO uint16_t*)PAGE0_BASE_ADDRESS);
    /* Get Page1 status */
    PageStatus1 = (*(__IO uint16_t*)PAGE1_BASE_ADDRESS);

    /* Check for invalid header states and repair if necessary */
    switch (PageStatus0)
    {
	case ERASED:
	    if (PageStatus1 == VALID_PAGE) /* Page0 erased, Page1 valid */
	    {
		/* Erase Page0 */
		FlashStatus = FLASH_ErasePage(PAGE0_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else if (PageStatus1 == RECEIVE_DATA) /* Page0 erased, Page1 receive */
	    {
		/* Erase Page0 */
		FlashStatus = FLASH_ErasePage(PAGE0_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
		/* Mark Page1 as valid */
		FlashStatus = FLASH_ProgramHalfWord(PAGE1_BASE_ADDRESS, VALID_PAGE);
		/* If program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else /* First EEPROM access (Page0&1 are erased) or invalid state -> format EEPROM */
	    {
		/* Erase both Page0 and Page1 and set Page0 as valid page */
		FlashStatus = EE_Format();
		/* If erase/program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    break;

	case RECEIVE_DATA:
	    if (PageStatus1 == VALID_PAGE) /* Page0 receive, Page1 valid */
	    {
		/* Transfer data from Page1 to Page0 */
		for (VarIdx = 0; VarIdx < NB_OF_VAR; VarIdx++)
		{
		    if (( *(__IO uint16_t*)(PAGE0_BASE_ADDRESS + 6)) == VirtAddVarTab[VarIdx])
		    {
			x = VarIdx;
		    }
		    if (VarIdx != x)
		    {
			/* Read the last variables' updates */
			ReadStatus = EE_ReadVariable(VirtAddVarTab[VarIdx], &DataVar);
			/* In case variable corresponding to the virtual address was found */
			if (ReadStatus != 0x1)
			{
			    /* Transfer the variable to the Page0 */
			    EepromStatus = EE_VerifyPageFullWriteVariable(VirtAddVarTab[VarIdx], DataVar);
			    /* If program operation was failed, a Flash error code is returned */
			    if (EepromStatus != FLASH_COMPLETE)
			    {
				return EepromStatus;
			    }
			}
		    }
		}
		/* Mark Page0 as valid */
		FlashStatus = FLASH_ProgramHalfWord(PAGE0_BASE_ADDRESS, VALID_PAGE);
		/* If program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
		/* Erase Page1 */
		FlashStatus = FLASH_ErasePage(PAGE1_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else if (PageStatus1 == ERASED) /* Page0 receive, Page1 erased */
	    {
		/* Erase Page1 */
		FlashStatus = FLASH_ErasePage(PAGE1_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
		/* Mark Page0 as valid */
		FlashStatus = FLASH_ProgramHalfWord(PAGE0_BASE_ADDRESS, VALID_PAGE);
		/* If program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else /* Invalid state -> format eeprom */
	    {
		/* Erase both Page0 and Page1 and set Page0 as valid page */
		FlashStatus = EE_Format();
		/* If erase/program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    break;

	case VALID_PAGE:
	    if (PageStatus1 == VALID_PAGE) /* Invalid state -> format eeprom */
	    {
		/* Erase both Page0 and Page1 and set Page0 as valid page */
		FlashStatus = EE_Format();
		/* If erase/program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else if (PageStatus1 == ERASED) /* Page0 valid, Page1 erased */
	    {
		/* Erase Page1 */
		FlashStatus = FLASH_ErasePage(PAGE1_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    else /* Page0 valid, Page1 receive */
	    {
		/* Transfer data from Page0 to Page1 */
		for (VarIdx = 0; VarIdx < NB_OF_VAR; VarIdx++)
		{
		    if ((*(__IO uint16_t*)(PAGE1_BASE_ADDRESS + 6)) == VirtAddVarTab[VarIdx])
		    {
			x = VarIdx;
		    }
		    if (VarIdx != x)
		    {
			/* Read the last variables' updates */
			ReadStatus = EE_ReadVariable(VirtAddVarTab[VarIdx], &DataVar);
			/* In case variable corresponding to the virtual address was found */
			if (ReadStatus != 0x1)
			{
			    /* Transfer the variable to the Page1 */
			    EepromStatus = EE_VerifyPageFullWriteVariable(VirtAddVarTab[VarIdx], DataVar);
			    /* If program operation was failed, a Flash error code is returned */
			    if (EepromStatus != FLASH_COMPLETE)
			    {
				return EepromStatus;
			    }
			}
		    }
		}
		/* Mark Page1 as valid */
		FlashStatus = FLASH_ProgramHalfWord(PAGE1_BASE_ADDRESS, VALID_PAGE);
		/* If program operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
		/* Erase Page0 */
		FlashStatus = FLASH_ErasePage(PAGE0_BASE_ADDRESS);
		/* If erase operation was failed, a Flash error code is returned */
		if (FlashStatus != FLASH_COMPLETE)
		{
		    return FlashStatus;
		}
	    }
	    break;

	default:  /* Any other state -> format eeprom */
	    /* Erase both Page0 and Page1 and set Page0 as valid page */
	    FlashStatus = EE_Format();
	    /* If erase/program operation was failed, a Flash error code is returned */
	    if (FlashStatus != FLASH_COMPLETE)
	    {
		return FlashStatus;
	    }
	    break;
    }

    return FLASH_COMPLETE;
}

/**
 * @brief  Returns the last stored variable data, if found, which correspond to
 *   the passed virtual address
 * @param  VirtAddress: Variable virtual address
 * @param  Data: Global variable contains the read variable value
 * @retval Success or error status:
 *           - 0: if variable was found
 *           - 1: if the variable was not found
 *           - NO_VALID_PAGE: if no valid page was found.
 */
uint16_t EE_ReadVariable(uint16_t VirtAddress, uint16_t* Data)
{
    uint16_t ValidPage = PAGE0;
    uint16_t AddressValue = 0x5555, ReadStatus = 1;
    uint32_t Address = 0x08010000, PageStartAddress = 0x08010000;

    /* Get active Page for read operation */
    ValidPage = EE_FindValidPage(READ_FROM_VALID_PAGE);

    /* Check if there is no valid page */
    if (ValidPage == NO_VALID_PAGE)
    {
	return  NO_VALID_PAGE;
    }

    /* Get the valid Page start Address */
    PageStartAddress = (uint32_t)(EEPROM_START_ADDRESS + (uint32_t)(ValidPage * PAGE_SIZE));

    /* Get the valid Page end Address */
    Address = (uint32_t)((EEPROM_START_ADDRESS - 2) + (uint32_t)((1 + ValidPage) * PAGE_SIZE));

    /* Check each active page address starting from end */
    while (Address > (PageStartAddress + 2))
    {
	/* Get the current location content to be compared with virtual address */
	AddressValue = (*(__IO uint16_t*)Address);

	/* Compare the read address with the virtual address */
	if (AddressValue == VirtAddress)
	{
	    /* Get content of Address-2 which is variable value */
	    *Data = (*(__IO uint16_t*)(Address - 2));

	    /* In case variable value is read, reset ReadStatus flag */
	    ReadStatus = 0;

	    break;
	}
	else
	{
	    /* Next address location */
	    Address = Address - 4;
	}
    }

    /* Return ReadStatus value: (0: variable exist, 1: variable doesn't exist) */
    return ReadStatus;
}

/**
 * @brief  Writes/upadtes variable data in EEPROM.
 * @param  VirtAddress: Variable virtual address
 * @param  Data: 16 bit data to be written
 * @retval Success or error status:
 *           - FLASH_COMPLETE: on success
 *           - PAGE_FULL: if valid page is full
 *           - NO_VALID_PAGE: if no valid page was found
 *           - Flash error code: on write Flash error
 */
uint16_t EE_WriteVariable(uint16_t VirtAddress, uint16_t Data)
{
    uint16_t Status = 0;

    /* Write the variable virtual address and value in the EEPROM */
    Status = EE_VerifyPageFullWriteVariable(VirtAddress, Data);

    /* In case the EEPROM active page is full */
    if (Status == PAGE_FULL)
    {
	/* Perform Page transfer */
	Status = EE_PageTransfer(VirtAddress, Data);
    }

    /* Return last operation status */
    return Status;
}

/**
 * @brief  Erases PAGE0 and PAGE1 and writes VALID_PAGE header to PAGE0
 * @param  None
 * @retval Status of the last operation (Flash write or erase) done during
 *         EEPROM formating
 */
static FLASH_Status EE_Format(void)
{
    FLASH_Status FlashStatus = FLASH_COMPLETE;

    /* Erase Page0 */
    FlashStatus = FLASH_ErasePage(PAGE0_BASE_ADDRESS);

    /* If erase operation was failed, a Flash error code is returned */
    if (FlashStatus != FLASH_COMPLETE)
    {
	return FlashStatus;
    }

    /* Set Page0 as valid page: Write VALID_PAGE at Page0 base address */
    FlashStatus = FLASH_ProgramHalfWord(PAGE0_BASE_ADDRESS, VALID_PAGE);

    /* If program operation was failed, a Flash error code is returned */
    if (FlashStatus != FLASH_COMPLETE)
    {
	return FlashStatus;
    }

    /* Erase Page1 */
    FlashStatus = FLASH_ErasePage(PAGE1_BASE_ADDRESS);

    /* Return Page1 erase operation status */
    return FlashStatus;
}

/**
 * @brief  Find valid Page for write or read operation
 * @param  Operation: operation to achieve on the valid page.
 *   This parameter can be one of the following values:
 *     @arg READ_FROM_VALID_PAGE: read operation from valid page
 *     @arg WRITE_IN_VALID_PAGE: write operation from valid page
 * @retval Valid page number (PAGE0 or PAGE1) or NO_VALID_PAGE in case
 *   of no valid page was found
 */
static uint16_t EE_FindValidPage(uint8_t Operation)
{
    uint16_t PageStatus0 = 6, PageStatus1 = 6;

    /* Get Page0 actual status */
    PageStatus0 = (*(__IO uint16_t*)PAGE0_BASE_ADDRESS);

    /* Get Page1 actual status */
    PageStatus1 = (*(__IO uint16_t*)PAGE1_BASE_ADDRESS);

    /* Write or read operation */
    switch (Operation)
    {
	case WRITE_IN_VALID_PAGE:   /* ---- Write operation ---- */
	    if (PageStatus1 == VALID_PAGE)
	    {
		/* Page0 receiving data */
		if (PageStatus0 == RECEIVE_DATA)
		{
		    return PAGE0;         /* Page0 valid */
		}
		else
		{
		    return PAGE1;         /* Page1 valid */
		}
	    }
	    else if (PageStatus0 == VALID_PAGE)
	    {
		/* Page1 receiving data */
		if (PageStatus1 == RECEIVE_DATA)
		{
		    return PAGE1;         /* Page1 valid */
		}
		else
		{
		    return PAGE0;         /* Page0 valid */
		}
	    }
	    else
	    {
		return NO_VALID_PAGE;   /* No valid Page */
	    }

	case READ_FROM_VALID_PAGE:  /* ---- Read operation ---- */
	    if (PageStatus0 == VALID_PAGE)
	    {
		return PAGE0;           /* Page0 valid */
	    }
	    else if (PageStatus1 == VALID_PAGE)
	    {
		return PAGE1;           /* Page1 valid */
	    }
	    else
	    {
		return NO_VALID_PAGE ;  /* No valid Page */
	    }

	default:
	    return PAGE0;             /* Page0 valid */
    }
}

/**
 * @brief  Verify if active page is full and Writes variable in EEPROM.
 * @param  VirtAddress: 16 bit virtual address of the variable
 * @param  Data: 16 bit data to be written as variable value
 * @retval Success or error status:
 *           - FLASH_COMPLETE: on success
 *           - PAGE_FULL: if valid page is full
 *           - NO_VALID_PAGE: if no valid page was found
 *           - Flash error code: on write Flash error
 */
static uint16_t EE_VerifyPageFullWriteVariable(uint16_t VirtAddress, uint16_t Data)
{
    FLASH_Status FlashStatus = FLASH_COMPLETE;
    uint16_t ValidPage = PAGE0;
    uint32_t Address = 0x08010000, PageEndAddress = 0x080107FF;

    /* Get valid Page for write operation */
    ValidPage = EE_FindValidPage(WRITE_IN_VALID_PAGE);

    /* Check if there is no valid page */
    if (ValidPage == NO_VALID_PAGE)
    {
	return  NO_VALID_PAGE;
    }

    /* Get the valid Page start Address */
    Address = (uint32_t)(EEPROM_START_ADDRESS + (uint32_t)(ValidPage * PAGE_SIZE));

    /* Get the valid Page end Address */
    PageEndAddress = (uint32_t)((EEPROM_START_ADDRESS - 2) + (uint32_t)((1 + ValidPage) * PAGE_SIZE));

    /* Check each active page address starting from begining */
    while (Address < PageEndAddress)
    {
	/* Verify if Address and Address+2 contents are 0xFFFFFFFF */
	if ((*(__IO uint32_t*)Address) == 0xFFFFFFFF)
	{
	    /* Set variable data */
	    FlashStatus = FLASH_ProgramHalfWord(Address, Data);
	    /* If program operation was failed, a Flash error code is returned */
	    if (FlashStatus != FLASH_COMPLETE)
	    {
		return FlashStatus;
	    }
	    /* Set variable virtual address */
	    FlashStatus = FLASH_ProgramHalfWord(Address + 2, VirtAddress);
	    /* Return program operation status */
	    return FlashStatus;
	}
	else
	{
	    /* Next address location */
	    Address = Address + 4;
	}
    }

    /* Return PAGE_FULL in case the valid page is full */
    return PAGE_FULL;
}

/**
 * @brief  Transfers last updated variables data from the full Page to
 *   an empty one.
 * @param  VirtAddress: 16 bit virtual address of the variable
 * @param  Data: 16 bit data to be written as variable value
 * @retval Success or error status:
 *           - FLASH_COMPLETE: on success
 *           - PAGE_FULL: if valid page is full
 *           - NO_VALID_PAGE: if no valid page was found
 *           - Flash error code: on write Flash error
 */
static uint16_t EE_PageTransfer(uint16_t VirtAddress, uint16_t Data)
{
    FLASH_Status FlashStatus = FLASH_COMPLETE;
    uint32_t NewPageAddress = 0x080103FF, OldPageAddress = 0x08010000;
    uint16_t ValidPage = PAGE0, VarIdx = 0;
    uint16_t EepromStatus = 0, ReadStatus = 0;

    /* Get active Page for read operation */
    ValidPage = EE_FindValidPage(READ_FROM_VALID_PAGE);

    if (ValidPage == PAGE1)       /* Page1 valid */
    {
	/* New page address where variable will be moved to */
	NewPageAddress = PAGE0_BASE_ADDRESS;

	/* Old page address where variable will be taken from */
	OldPageAddress = PAGE1_BASE_ADDRESS;
    }
    else if (ValidPage == PAGE0)  /* Page0 valid */
    {
	/* New page address where variable will be moved to */
	NewPageAddress = PAGE1_BASE_ADDRESS;

	/* Old page address where variable will be taken from */
	OldPageAddress = PAGE0_BASE_ADDRESS;
    }
    else
    {
	return NO_VALID_PAGE;       /* No valid Page */
    }

    /* Set the new Page status to RECEIVE_DATA status */
    FlashStatus = FLASH_ProgramHalfWord(NewPageAddress, RECEIVE_DATA);
    /* If program operation was failed, a Flash error code is returned */
    if (FlashStatus != FLASH_COMPLETE)
    {
	return FlashStatus;
    }

    /* Write the variable passed as parameter in the new active page */
    EepromStatus = EE_VerifyPageFullWriteVariable(VirtAddress, Data);
    /* If program operation was failed, a Flash error code is returned */
    if (EepromStatus != FLASH_COMPLETE)
    {
	return EepromStatus;
    }

    /* Transfer process: transfer variables from old to the new active page */
    for (VarIdx = 0; VarIdx < NB_OF_VAR; VarIdx++)
    {
	if (VirtAddVarTab[VarIdx] != VirtAddress)  /* Check each variable except the one passed as parameter */
	{
	    /* Read the other last variable updates */
	    ReadStatus = EE_ReadVariable(VirtAddVarTab[VarIdx], &DataVar);
	    /* In case variable corresponding to the virtual address was found */
	    if (ReadStatus != 0x1)
	    {
		/* Transfer the variable to the new active page */
		EepromStatus = EE_VerifyPageFullWriteVariable(VirtAddVarTab[VarIdx], DataVar);
		/* If program operation was failed, a Flash error code is returned */
		if (EepromStatus != FLASH_COMPLETE)
		{
		    return EepromStatus;
		}
	    }
	}
    }

    /* Erase the old Page: Set old Page status to ERASED status */
    FlashStatus = FLASH_ErasePage(OldPageAddress);
    /* If erase operation was failed, a Flash error code is returned */
    if (FlashStatus != FLASH_COMPLETE)
    {
	return FlashStatus;
    }

    /* Set new Page status to VALID_PAGE status */
    FlashStatus = FLASH_ProgramHalfWord(NewPageAddress, VALID_PAGE);
    /* If program operation was failed, a Flash error code is returned */
    if (FlashStatus != FLASH_COMPLETE)
    {
	return FlashStatus;
    }

    /* Return last operation flash status */
    return FlashStatus;
}

/**
 * @}
 */ 

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/