#include "w25n01gv.h"

/*---------------------------------以下为接口----------------------------------*/
/*--------------------------请根据自己的实际情况修改---------------------------*/

/*
函数原型：void FlashDelay(u16 n);
函数功能：延时
参数：n 延时的毫秒数
返回值：无
*/
void (*FlashDelay)(unsigned short n) = (void (*)(unsigned short))&delay;

/*
函数原型：u8 FlashRW(u8 dat);
函数功能：SPI读写一字节
参数：dat 要写入的数据
返回值：读出的数据
*/
unsigned char (*FlashRW)(unsigned char dat) = &SPI_ReadWriteByte;

/*
函数原型：void FlashEnable(u8 s);
函数功能：SPI片选
参数：s 片选状态，0未选中，非0选中
返回值：无
*/
void FlashEnable(unsigned char s)
{
	if (s) 
	{
		SPI_CS = 0;
	}
	else
	{
		SPI_CS = 1;
	}
}

/*--------------------------------以下为驱动程序-------------------------------*/

unsigned char FlashReset(void)
{
	FlashEnable(1);
	FlashRW(FLASH_DEVICE_RESET);
	FlashEnable(0);
	FlashDelay(1);//手册上说复位时间约为5-500us，这里延时1ms
	if(FlashWaitBusy(100))
	{
		return 1;//等待复位超时
	}
	return 0;
}

unsigned char FlashInit(void)
{
	unsigned int id = 0;

	FlashEnable(1);
	FlashRW(FLASH_JEDEC_ID);
	id |= FlashRW(0x00) << 24;//第一字节忽略
	id |= FlashRW(0x00) << 16;//第二字为0xEF
	id |= FlashRW(0x00) << 8;//第三字为0xAA
	id |= FlashRW(0x00);//第四字为0x21
	FlashEnable(0);
	
	if((id & FLASH_ID_W25N01GV) != FLASH_ID_W25N01GV)
	{
		//芯片型号不对，或芯片已损坏？
		return 1;
	}

	if(FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_BBM_LUT_FULL)
	{
		//坏块映射表已满，继续使用不能保证数据的正确性
		return 2;
	}

	//芯片设置
	id = FlashReadStatusRegister(FLASH_STATUS_REG1_ADDR);
	id = 0;//禁用所有写保护
	FlashWriteStatusRegister(FLASH_STATUS_REG1_ADDR, id & 0x000000FF);

	id = FlashReadStatusRegister(FLASH_STATUS_REG2_ADDR);
	id |= (0x10 | 0x80);//开启ECC，禁用读取缓冲区
	FlashWriteStatusRegister(FLASH_STATUS_REG2_ADDR, id & 0x000000FF);

	return 0;
}

//等待芯片操作完成，时间单位ms
unsigned char FlashWaitBusy(unsigned short int timeout)
{
	while(timeout--)
	{
		if((FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_BUSY) != FLASH_SR_BUSY)
		{
			return 0;//等待结束
		}
		FlashDelay(1);
	}
	return 1;//等待超时
}

void FlashWriteEnable(void)
{
	FlashEnable(1);
	FlashRW(FLASH_WRITE_ENABLE);
	FlashEnable(0);
}

void FlashWriteDisable(void)
{
	FlashEnable(1);
	FlashRW(FLASH_WRITE_DISABLE);
	FlashEnable(0);
}

unsigned char FlashReadStatusRegister(unsigned char RegAddr)
{
	unsigned char tmp;

	FlashEnable(1);
	FlashRW(FLASH_READ_STATUS_REGISTER);
	FlashRW(RegAddr);
	tmp = FlashRW(0x00);
	FlashEnable(0);

	return tmp;
}

void FlashWriteStatusRegister(unsigned char RegAddr, unsigned char Value)
{
	FlashEnable(1);
	FlashRW(FLASH_WRITE_STATUS_REGISTER);
	FlashRW(RegAddr);
	FlashRW(Value);
	FlashEnable(0);
}

//读取一页，返回值为ECC校验结果
unsigned char FlashReadPage(unsigned short int page, unsigned char *buf)
{
	unsigned short int i = 0;

	//输入要读取的页地址
	FlashEnable(1);
	FlashRW(FLASH_PAGE_DATA_READ);
	FlashRW(0x00);
	FlashRW((unsigned char)(page >> 8));
	FlashRW((unsigned char)(page & 0x00FF));
	FlashEnable(0);
	FlashDelay(1);
	
	//开始读取
	FlashEnable(1);
	FlashRW(FLASH_READ);
	FlashRW(0x00);
	FlashRW(0x00);
	FlashRW(0x00);
	//三个空字节后开始接收数据
	for(i = 0; i < 2048; i++)
	{
		*buf = FlashRW(0x00);
		buf++;
	}
	FlashEnable(0);

	return FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & 0x30;
}

//写入一页，0成功，1失败
unsigned char FlashWritePage(unsigned short int page, unsigned char *buf)
{
	unsigned short int i = 0;
	
	FlashWriteEnable();
	FlashDelay(1);
	
	//将数据送到Flash
	FlashEnable(1);
	FlashRW(FLASH_PROGRAM_DATA_LOAD);
	FlashRW(0x00);//填充字节
	FlashRW(0x00);//填充字节
	for(i = 0; i < 2048; i++)
	{
		FlashRW(*buf);
		buf++;
	}
	FlashEnable(0);
	FlashDelay(1);
	
	//执行写入操作
	FlashEnable(1);
	FlashRW(FLASH_PROGRAM_ECECUTE);
	FlashRW(0x00);
	FlashRW((unsigned char)(page >> 8));
	FlashRW((unsigned char)(page & 0x00FF));
	FlashEnable(0);

	FlashWaitBusy(100);//等待写入完成

	//检查是否写入成功
	if(FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_WRITE_FAIL)
	{
		return 1;
	}
	return 0;
}

//擦除区块，0成功，1失败
unsigned char FlashBlockErase(unsigned short int BlockNum)
{
	FlashWriteEnable();
	FlashEnable(1);
	FlashRW(FLASH_BLOCK_ERASE);
	FlashRW((unsigned char)(0x00));
	FlashRW((unsigned char)(BlockNum >> 8));
	FlashRW((unsigned char)(BlockNum & 0x00FF));
	FlashEnable(0);
	if(FlashWaitBusy(100))
	{
		//等待擦除完成，手册上说最大不超过10ms
		return 1;
	}
	
	//检查是否擦除成功
	if(FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_ERASE_FAIL)
	{
		return 1;
	}
	return 0;
}

//区块扫描，可以用来检查擦除是否成功或扫描出厂时的坏块标记
unsigned char BlockScan(unsigned short int BlockNum)
{
	int i = 0;

	//把块地址换算成页地址
	BlockNum <<= 6;

	FlashEnable(1);
	FlashRW(FLASH_PAGE_DATA_READ);
	FlashRW(0x00);
	FlashRW((unsigned char)(BlockNum >> 8));
	FlashRW((unsigned char)(BlockNum & 0x00FF));
	FlashEnable(0);

	FlashDelay(1);
	//开始读取
	FlashEnable(1);
	FlashRW(FLASH_READ);
	FlashRW(0x00);
	FlashRW(0x00);
	FlashRW(0x00);
	//三个空字节后开始接收数据
	for(i = 0; i < 128 * 1024; i++)
	{
		if(FlashRW(0x00) != 0xFF)
		{
			FlashEnable(0);
			return 1;
		}
	}
	FlashEnable(0);

	return 0;
}

//专门用于找出出厂时的坏块标记，手册上说出厂时坏块的第一页的第一个字节会被标记为非0xFF，
unsigned char BadBlockScan(unsigned short int BlockNum)
{
	//把块地址换算成页地址
	BlockNum <<= 6;

	FlashEnable(1);
	FlashRW(FLASH_PAGE_DATA_READ);
	FlashRW(0x00);
	FlashRW((unsigned char)(BlockNum >> 8));
	FlashRW((unsigned char)(BlockNum & 0x00FF));
	FlashEnable(0);

	FlashDelay(1);
	//开始读取
	FlashEnable(1);
	FlashRW(FLASH_READ);
	FlashRW(0x00);
	FlashRW(0x00);
	FlashRW(0x00);
	//三个空字节后开始接收数据
	//出厂时，坏块的第一页的第一个字节会被标记为非0xFF，后面的就不用继续扫描了
	if(FlashRW(0x00) != 0xFF)
	{
		FlashEnable(0);
		return 1;
	}
	FlashEnable(0);

	return 0;
}

//LBA(Logical Block Address)是坏块地址，PBA(Physical Block Address)是要替换的区块地址
//返回0正常，1坏块表已满
unsigned char BadBlockMapping(unsigned short int LBA, unsigned short int PBA)
{
	if(FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_BBM_LUT_FULL)
	{
		return 1;
	}

	FlashEnable(1);
	FlashRW(FLASH_BAD_BLOCK_MANAGEMENT);
	FlashRW((unsigned char)(LBA >> 8));
	FlashRW((unsigned char)(LBA & 0x00FF));
	FlashRW((unsigned char)(PBA >> 8));
	FlashRW((unsigned char)(PBA & 0x00FF));
	FlashEnable(0);

	return 0;
}

//Bad Block Management Look Up Table
//BBMLUT需要80字节存储（实际上应当是40个unsigned short数据）
//格式是LBA0,PBA0,LBA1,PBA1......LBA19,PBA19
void ReadBBMLUT(unsigned short int *BBMLUT)
{
	int i = 0;

	FlashEnable(1);
	FlashRW(FLASH_READ_BBM_LUT);
	FlashRW(0x00);
	for(i = 0; i < 80; i++)
	{
		*BBMLUT = FlashRW(0x00) << 8;
		BBMLUT++;
		*BBMLUT |= FlashRW(0x00);
	}
	FlashEnable(0);
}

//读出最后一个ECC错误的页地址
unsigned short int LastECCFailPageAddr(void)
{
	unsigned short int PageAddr = 0;

	FlashEnable(1);
	FlashRW(FLASH_LAST_ECC_FAILURE_PAGE_ADDR);
	FlashRW(0x00);
	PageAddr |= FlashRW(0x00) << 8;
	PageAddr |= FlashRW(0x00);
	FlashEnable(0);

	return PageAddr;
}

//在正式使用前建议执行一次坏块扫描
//使用前不要向Flash写入任何数据，否则可能覆盖出厂时的坏块信息
void BadBlockManage(void)
{
	unsigned short int i = 0, n = 0;
	unsigned short int BBT[40] = {0};//Bad Block Table

	printf("开始坏块扫描 \r\n");
	for(i = 0; i < 1024; i++)
	{
		printf("正在扫描第 %d 块 \r\n", i);
		if(BadBlockScan(i))//快速扫描，只扫描每页的第一字节
		{
			printf("第 %d 块为坏块 \r\n", i);
			//自动填入映射表还是手动填？

			if(FlashReadStatusRegister(FLASH_STATUS_REG3_ADDR) & FLASH_SR_BBM_LUT_FULL)
			{
				printf("坏块映射表已满，无法映射 \r\n");
			}
			else
			{
				ReadBBMLUT(BBT);
				//1000到1023一共24个Block用于替换，BBMLUT一共能保存20个映射关系
				//多出来的4块是考虑到这20个块中还有坏块的情况
				for(n = 0; n < 20; n++)
				{
					if(BBT[n * 2] == 0x0000 && BBT[n * 2 + 1] == 0x0000)
					{
						n += 1000;
						BadBlockMapping(i, n);
						printf("第 %d 块被映射为第 %d 块 \r\n", i, n);
						break;
					}
				}
			}
		}
	}
	printf("坏块扫描结束 \r\n");
}