读写SPI FLASH--驱动部分（6） before, FLASH

yuyang911220

/* fill pre opcode */
    addr = base + SPI_PREOP;
    val = readw((void *)(spi_char.mem_virt+SPI_PREOP));
    SPI_DBG("before init, SPI_PREOOP=%08x/n", val);
    val = SPI_WR_ENABLE | (SPI_WSR_ENABLE << 8);
    writew(val, (void *)addr);
    val = readw((void *)(spi_char.mem_virt+SPI_PREOP));
    SPI_DBG("after init, SPI_PREOP=%08x/n", val);
   
   
    /* disable Atomic Cycle Sequence */
    val = readw((void *)(spi_char.mem_virt+SPI_CTRL));
    val &= ~SPI_CTRL_ACS;
    val &= ~SPI_CTRL_SPOP;
    writew(val, (void*)(spi_char.mem_virt+SPI_CTRL));
}


loff_t spi_lseek(struct file *filp, loff_t off, int whence)
{
    loff_t newpos;
   
    switch (whence)
    {
        case 0: /* SEEK_SET */
            newpos = off;
            break;
         
        case 1: /* SEEK_CUR */
            newpos = spi_char.fp + off;
            break;
            
        case 2: /* SEEK_END */
            newpos = spi_char.fp + off;
            break;
         
         default: /* cant't happen */
            return (-EINVAL);
            break;
     }
     
     if(newpos < 0 || newpos >= SPI_FLASH_SIZE)
     {
        return (-EINVAL);
     }
     
     spi_char.fp = newpos;
     return (newpos);
}

// Linux file operations
struct file_operations file_ops =
{
    .owner =     THIS_MODULE,
    .read =      spi_read,
    .write =     spi_write,
    .llseek = spi_lseek,
     .open =        spi_open,
     .release =   spi_release,
     .ioctl    = spi_ioctl,
};