我用9160开发SPI接口连接了一个W25Q64FW的外部FLASH，同步跟踪可以，发现可以读取flash ID，扇区擦除之后立即读取可以发现扇区确实擦除成功了，数据变成了0xff，但是我写入一串字符串之后，再读取出来却都是0了，看上去好像是写入失败，不知道是怎么回事，下面是我的代码：
void SPI_Flash_Init(void)
{
spi_flash = device_get_binding(FLASH_DEVICE);
if (!spi_flash)
{
printk("Could not get %s device\n", FLASH_DEVICE);
return;
}

spi_cfg.operation = SPI_OP_MODE_MASTER | SPI_WORD_SET(8);
spi_cfg.frequency = 4000000;
spi_cfg.slave = 0;

spi_cs_ctr.gpio_dev = device_get_binding(FLASH_PORT);
if (!spi_cs_ctr.gpio_dev)
{
	printk("Unable to get GPIO SPI CS device\n");
	return;
}
spi_cs_ctr.gpio_pin = CS;
spi_cs_ctr.delay = 0U;
spi_cfg.cs = &spi_cs_ctr;

}

void flash_init(void)
{
gpio_flash = device_get_binding(FLASH_PORT);
if(!gpio_flash)
{
printk("Cannot bind gpio device\n");
return;
}

gpio_pin_configure(gpio_flash, CS, GPIO_DIR_OUT);

SPI_Flash_Init();

}

void SPIFlash_Erase_Sector(uint32_t SecAddr)
{
int err;

//发送写使能命令
SpiFlash_Write_Enable();

//扇区擦除命令
spi_tx_buf[0] = SPIFlash_SecErase;		
//24位地址
spi_tx_buf[1] = (uint8_t)((SecAddr&0x00ff0000)>>16);
spi_tx_buf[2] = (uint8_t)((SecAddr&0x0000ff00)>>8);
spi_tx_buf[3] = (uint8_t)SecAddr;

tx_buff.buf = spi_tx_buf;
tx_buff.len = SPIFLASH_CMD_LENGTH;
tx_bufs.buffers = &tx_buff;
tx_bufs.count = 1;

err = spi_transceive(spi_flash, &spi_cfg, &tx_bufs, NULL);
if(err)
{
	printk("SPI error: %d\n", err);
}

//等待W25Q128FV完成操作
SpiFlash_Wait_Busy();

}

uint16_t SpiFlash_ReadID(void)
{
int err;
uint16_t dat = 0;

//准备数据
spi_tx_buf[0] = SPIFlash_ReadID;
spi_tx_buf[1] = 0x00;
spi_tx_buf[2] = 0x00;
spi_tx_buf[3] = 0x00;
spi_tx_buf[4] = 0xFF;
spi_tx_buf[5] = 0xFF;

tx_buff.buf = spi_tx_buf;
tx_buff.len = 6;
tx_bufs.buffers = &tx_buff;
tx_bufs.count = 1;

memset(spi_rx_buf, 0, sizeof(spi_rx_buf));

rx_buff.buf = spi_rx_buf;
rx_buff.len = 6;
rx_bufs.buffers = &rx_buff;
rx_bufs.count = 1;

err = spi_transceive(spi_flash, &spi_cfg, &tx_bufs, &rx_bufs);
if(err)
{
	printk("SPI error: %d\n", err);
}
else
{
	printk("TX sent: %x,%x,%x,%x,%x,%x\n", 
		spi_tx_buf[0],
		spi_tx_buf[1],
		spi_tx_buf[2],
		spi_tx_buf[3],
		spi_tx_buf[4],
		spi_tx_buf[5]
		);
	
	printk("RX recv: %x,%x,%x,%x,%x,%x\n", 
		spi_rx_buf[0],
		spi_rx_buf[1],
		spi_rx_buf[2],
		spi_rx_buf[3],
		spi_rx_buf[4],
		spi_rx_buf[5]
		);
	
	//接收数组最后两个字节才是读取的ID
	dat|=spi_rx_buf[4]<<8;  
	dat|=spi_rx_buf[5];
	
	printk("flash ID: %x\n", dat);
}
return dat;

}

uint8_t SpiFlash_Write_Page(uint8_t *pBuffer, uint32_t WriteAddr, uint32_t size)
{
int err;

//检查写入的数据长度是否合法，写入长度不能超过页面的大小
if (size > (SPIFlash_PAGE_SIZE - (WriteAddr%SPIFlash_PAGE_SIZE)))
{
	return false;
}

if(size == 0) 
	return false;

//发送写使能命令
SpiFlash_Write_Enable();

//页编程命令
spi_tx_buf[0] = SPIFlash_PageProgram;
//24位地址，高地址在前
spi_tx_buf[1] = (uint8_t)((WriteAddr&0x00ff0000)>>16);
spi_tx_buf[2] = (uint8_t)((WriteAddr&0x0000ff00)>>8);
spi_tx_buf[3] = (uint8_t)WriteAddr;

memcpy(&spi_tx_buf[4], pBuffer, size);

tx_buff.buf = spi_tx_buf;
tx_buff.len = SPIFLASH_CMD_LENGTH+size;
tx_bufs.buffers = &tx_buff;
tx_bufs.count = 1;

err = spi_transceive(spi_flash, &spi_cfg, &tx_bufs, NULL);
if(err)
{
	printk("SPI error: %d\n", err);
}

}

uint8_t SpiFlash_Read(uint8_t *pBuffer,uint32_t ReadAddr,uint32_t size)
{
int err;
uint8_t read_size;

spi_tx_buf[0] = SPIFlash_ReadData;
//24位地址，高地址在前
spi_tx_buf[1] = (uint8_t)((ReadAddr&0x00ff0000)>>16);
spi_tx_buf[2] = (uint8_t)((ReadAddr&0x0000ff00)>>8);
spi_tx_buf[3] = (uint8_t)ReadAddr;

tx_buff.buf = spi_tx_buf;
tx_buff.len = SPIFLASH_CMD_LENGTH;
tx_bufs.buffers = &tx_buff;
tx_bufs.count = 1;

err = spi_transceive(spi_flash, &spi_cfg, &tx_bufs, NULL);
if(err)
{
	printk("SPI error: %d\n", err);
}

//开始读取数据
while(size!=0)
{
	if(size<=SPI_TXRX_MAX_LEN)
	{
		read_size = size;
		size = 0;
	}
	else
	{
		read_size = SPI_TXRX_MAX_LEN;
		size -= SPI_TXRX_MAX_LEN;
	}

	rx_buff.buf = pBuffer;
	rx_buff.len = read_size;
	rx_bufs.buffers = &rx_buff;
	rx_bufs.count = 1;

	err = spi_transceive(spi_flash, &spi_cfg, NULL, &rx_bufs);
	if(err)
	{
		printk("SPI error: %d\n", err);
	}
	
	pBuffer += read_size;
}

return true;

}

void test_flash(void)
{
uint16_t flash_id = 0x00;
uint16_t len = 0, i,j=1;
u8_t tmpbuf[128]={0};

flash_init();

flash_id = SpiFlash_ReadID();
sprintf(tmpbuf, "FLASH ID:%X", flash_id);
LCD_ShowString(0,60,tmpbuf);
printk("flash_id: %x\n", flash_id);

strcpy(my_tx_buf, "Hello World!");
len = strlen("Hello World!") + 1;

//写之前需要先执行擦除操作
SPIFlash_Erase_Sector(0);
SpiFlash_Read(my_rx_buf,0,len);
LCD_ShowString(0,80,"FLASH首先擦除");

//写入数据
SpiFlash_Write_Page(my_tx_buf,0,len);
LCD_ShowString(0,100,"FLASH写入数据:");
LCD_ShowString(0,120,my_tx_buf);

//读出数据
SpiFlash_Read(my_rx_buf,0,len);
LCD_ShowString(0,140,"FLASH读出数据:");
LCD_ShowString(0,160,my_rx_buf);

}