linux3.4.2之块设备驱动完整程序

  1 /*参考drivers/block/xd.c
  2 *以及drivers/block/z2ram.c
  3 */
  4 #include <linux/module.h>
  5 #include <linux/errno.h>
  6 #include <linux/interrupt.h>
  7 #include <linux/mm.h>
  8 #include <linux/fs.h>
  9 #include <linux/kernel.h>
 10 #include <linux/timer.h>
 11 #include <linux/genhd.h>
 12 #include <linux/hdreg.h>
 13 #include <linux/ioport.h>
 14 #include <linux/init.h>
 15 #include <linux/wait.h>
 16 #include <linux/blkdev.h>
 17 #include <linux/mutex.h>
 18 #include <linux/blkpg.h>
 19 #include <linux/delay.h>
 20 #include <linux/io.h>
 21 #include <linux/gfp.h>
 22 
 23 #include <asm/uaccess.h>
 24 #include <asm/dma.h>
 25 
 26 
 27 static struct gendisk *ramblock_disk;
 28 static struct request_queue *ramblock_queue;
 29 static DEFINE_SPINLOCK(ramblock_lock);
 30 
 31 #define RAMBLOCKSIZE (1024*1024)
 32 static int major;
 33 static unsigned char *ramblock;
 34 
 35 static int ramblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 36 {
 37 
 38     geo->heads = 2;
 39     geo->sectors = 32;
 40     geo->cylinders = RAMBLOCKSIZE/2/32/512;
 41     return 0;
 42 }
 43 
 44 static const struct block_device_operations ramblock_fops = {
 45     .owner    = THIS_MODULE,
 46     .getgeo = ramblock_getgeo,
 47 };
 48 
 49 static void do_ramblock_request (struct request_queue * q)
 50 {
 51       static int cnt = 0;
 52       struct request *req;
 53       
 54       printk("do_ramblock_request %d : \n",++cnt);
 55       req = blk_fetch_request(q);
 56       while(req){
 57           unsigned long start = blk_rq_pos(req) << 9; //源
 58         unsigned long len  = blk_rq_cur_bytes(req);  //长度
 59         /*目的：req->buffer*/
 60         if (rq_data_dir(req) == READ)
 61                 memcpy(req->buffer, ramblock+start, len);
 62             else
 63                 memcpy(ramblock+start, req->buffer, len);
 64             
 65          if (!__blk_end_request_cur(req, 0))
 66             req = blk_fetch_request(q); 
 67       }
 68 }
 69 
 70 static int ramblock_init(void)
 71 {
 72     ramblock_disk = alloc_disk(16); //次设备号个数，分区数+1
 73 
 74     ramblock_queue = blk_init_queue(do_ramblock_request, &ramblock_lock);
 75 
 76     major = register_blkdev(0, "ramblock"); // /dev/ramblock
 77     
 78         ramblock_disk->major = major;
 79         ramblock_disk->first_minor = 0;
 80         sprintf(ramblock_disk->disk_name, "ramblock");
 81         ramblock_disk->fops = &ramblock_fops;
 82         ramblock_disk->queue = ramblock_queue;
 83         set_capacity(ramblock_disk, RAMBLOCKSIZE/512);  //设置容量，以扇区512字节为单位
 84 
 85         ramblock = kzalloc(RAMBLOCKSIZE,GFP_KERNEL);
 86         if(ramblock == NULL){
 87           printk("alloc ramblock failed!\n");
 88           return -1;
 89         }
 90         add_disk(ramblock_disk);
 91     return 0;
 92 }
 93 
 94 static void ramblock_exit(void)
 95 {
 96        del_gendisk(ramblock_disk); 
 97        unregister_blkdev(major,"ramblock");
 98        blk_cleanup_queue(ramblock_queue);
 99        put_disk(ramblock_disk);
100        kfree(ramblock);
101 }
102 
103 module_init(ramblock_init);
104 module_exit(ramblock_exit);
105 
106 MODULE_LICENSE("GPL");
107 MODULE_AUTHOR("[email protected]");