/************************************************************************************
 * arch/arm/src/stm32/stm32_flash.c
 *
 *   Copyright (C) 2011 Uros Platise. All rights reserved.
 *   Author: Uros Platise <uros.platise@isotel.eu>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ************************************************************************************/

/** \file
 *  \author Uros Platise
 *  \brief STM32 Flash - Program and Data Memory
 * 
 * Provides standard flash access functions, to be used also by the
 * drivers/mtd/progmem.c program memory flash mtd driver.
 * The interface is defined in the include/nuttx/progmem.h
 * 
 * Requirements during write/erase operations on FLASH:
 *  - HSI must be ON.
 *  - Low Power Modes are not permitted during write/erase
 */
 
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <errno.h>

#include "stm32_flash.h"
#include "stm32_rcc.h"
#include "stm32_waste.h"
#include "up_arch.h"


/************************************************************************************
 * Declarations
 ************************************************************************************/

#define FLASH_KEY1      0x45670123
#define FLASH_KEY2      0xCDEF89AB


/************************************************************************************
 * Private Functions
 ************************************************************************************/

void stm32_flash_unlock(void)
{
    while( getreg32(STM32_FLASH_SR) & FLASH_SR_BSY ) up_waste();

    if ( getreg32(STM32_FLASH_CR) & FLASH_CR_LOCK ) {
    
        /* Unlock sequence */
        
        putreg32(FLASH_KEY1, STM32_FLASH_KEYR);
        putreg32(FLASH_KEY2, STM32_FLASH_KEYR);
    }
}


void stm32_flash_lock(void)
{
    modifyreg16(STM32_FLASH_CR, 0, FLASH_CR_LOCK);
}


/************************************************************************************
 * Public Functions
 ************************************************************************************/

uint16_t up_progmem_npages(void)
{
    return STM32_FLASH_NPAGES;
}


bool up_progmem_isuniform(void)
{
    return TRUE;
}


uint16_t up_progmem_pagesize(uint16_t page)
{
    return STM32_FLASH_PAGESIZE;
}


int up_progmem_getpage(uint32_t addr)
{
    if (addr >= STM32_FLASH_SIZE)
        return -EFAULT;

    return addr / STM32_FLASH_PAGESIZE;
}


int up_progmem_erasepage(uint16_t page)
{
    uint32_t addr;
    uint16_t count;

    if (page >= STM32_FLASH_NPAGES)
        return -EFAULT;

    /* Get flash ready and begin erasing single page */
    
    if ( !(getreg32(STM32_RCC_CR) & RCC_CR_HSION) )
        return -EPERM;
    
    stm32_flash_unlock();
        
    modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_PER);
    putreg32(page * STM32_FLASH_PAGESIZE, STM32_FLASH_AR);
    modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_STRT);
    
    while( getreg32(STM32_FLASH_SR) & FLASH_SR_BSY ) up_waste();
    
    modifyreg32(STM32_FLASH_CR, FLASH_CR_PER, 0);
    
    /* Verify */
    
    for (addr = page * STM32_FLASH_PAGESIZE + STM32_FLASH_BASE, count = STM32_FLASH_PAGESIZE; 
         count; count-=4, addr += 4) {
         
        if (getreg32(addr) != 0xFFFFFFFF)
            return -EIO;
    }
    
    return STM32_FLASH_PAGESIZE;
}


int up_progmem_ispageerased(uint16_t page)
{
    uint32_t addr;
    uint16_t count;
    uint16_t bwritten = 0;

    if (page >= STM32_FLASH_NPAGES)
        return -EFAULT;

    /* Verify */
    
    for (addr = page * STM32_FLASH_PAGESIZE + STM32_FLASH_BASE, count = STM32_FLASH_PAGESIZE; 
         count; count--, addr++) {
         
        if (getreg8(addr) != 0xFF) bwritten++;
    }
    
    return bwritten;
}


int up_progmem_write(uint32_t addr, const void *buf, size_t count)
{
    uint16_t *hword = (uint16_t *)buf;
    size_t written = count;

    /* STM32 requires half-word access */
    
    if (count & 1)
        return -EINVAL;
        
    /* Check for valid address range */
        
    if ( (addr+count) >= STM32_FLASH_SIZE)
        return -EFAULT;

    /* Get flash ready and begin flashing */
    
    if ( !(getreg32(STM32_RCC_CR) & RCC_CR_HSION) )
        return -EPERM;
        
    stm32_flash_unlock();
    
    modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_PG);
    
    for (addr += STM32_FLASH_BASE; count; count--, hword++, addr+=2) {
            
        /* Write half-word and wait to complete */
    
        putreg16(*hword, addr);
        
        while( getreg32(STM32_FLASH_SR) & FLASH_SR_BSY ) up_waste();
        
        /* Verify */
        
        if (getreg32(STM32_FLASH_SR) & FLASH_SR_WRPRT_ERR) {
            modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
            return -EROFS;
        }
        
        if (getreg16(addr) != *hword) {
            modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
            return -EIO;
        }
        
    }
    
    modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
    return written;
}