Linux FLASH驅動設計二

塊裝置驅動系統分析：

功能：把記憶體劃出512k，然後利用驅動程式做成塊裝置進行相應的訪問。

#include #include #include #include #include /* printk() */
#include /* kmalloc() */
#include /* everything... */
#include /* error codes */
#include #include /* size_t */
#include /* o_accmode */
#include /* hdio_getgeo */
#include #include #include #include #include /* invalidate_bdev */
#include module_license("dual bsd/gpl");
static int major = 0;
static int sect_size = 512;
static int nsectors = 1024; 
/** the internal representation of our device.
*/struct blk_dev
;struct blk_dev *dev;
/** handle an i/o request, in sectors.
*/static void blk_transfer(struct blk_dev *dev, unsigned long sector,
unsigned long nsect, char *buffer, int write)
if (write)
memcpy(dev->data + offset, buffer, nbytes);
else
memcpy(buffer, dev->data + offset, nbytes);}/*
* the ****** form of the request function.
*/static void blk_request(struct request_queue *q) }}
/** the device operations structure.
*/static struct block_device_operations blk_ops = ;/*
* set up our internal device.
*/static void setup_device()
dev->queue = blk_init_queue(blk_request, null);//塊裝置請求佇列初始化，第乙個引數為請求佇列呼叫函式，第二個引數為訊號量
if (dev->queue == null)
goto out_vfree;
blk_queue_logical_block_size(dev->queue, sect_size);//指明裝置扇區大小
dev->queue->queuedata = dev;
/* * and the gendisk structure.
*/ dev->gd = alloc_disk(1);//為塊裝置分配struct gendisk結構
if (! dev->gd) 
/*初始化struct gendisk結構體

*/ dev->gd->major = major;

//塊裝置主裝置號dev->gd->first_minor = 0;

//塊裝置起始次裝置號dev->gd->fops = &blk_ops;

//塊裝置操作函式局dev->gd->queue = dev->queue;

//塊裝置請求佇列dev->gd->private_data = dev;sprintf (dev->gd->disk_name, "simp_blk%d", 0);

//塊裝置名set_capacity(dev->gd, nsectors*(sect_size/sect_size));

//裝置塊裝置扇區數add_disk(dev->gd);

//向核心新增（註冊）塊裝置return;out_vfree:if (dev->data) vfree(dev->data);}static int __init blk_init(void)dev = kmalloc(sizeof(struct blk_dev), gfp_kernel);if (dev == null) goto out_unregister; setup_device();

//建立塊裝置初始化、註冊函式，自己實現 return 0;out_unregister:unregister_blkdev(major, "sbd");return -enomem;}static void blk_exit(void)if (dev->queue)blk_cleanup_queue(dev->queue);if (dev->data)vfree(dev->data);unregister_blkdev(major, "blk");kfree(dev);}module_init(blk_init);module_exit(blk_exit);

塊裝置驅動設計流程圖：

Linux FLASH驅動設計二

linux flash裝置驅動

Linux Flash驅動 1 塊裝置系統架構

Linux驅動設計硬體基礎（二）

Linux FLASH驅動設計二

linux flash裝置驅動

Linux Flash驅動 1 塊裝置系統架構

Linux驅動設計硬體基礎（二）

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