2014-04-19 块设备驱动程序（模拟内存）__

实验描述：

块设备驱动程序（模拟内存）

内核版本：

Linux 2.6.38

开发板： 

Mini 6410

程序实现：

#include <linux/init.h>  #include <linux/module.h>  #include <linux/device.h>#include <linux/cdev.h> #include <linux/fs.h> #include <linux/slab.h>#include <linux/delay.h>#include <linux/clk.h>#include <asm/irq.h>#include <asm/uaccess.h>#include <linux/time.h>#include <linux/interrupt.h>#include <linux/io.h>#include <linux/err.h>#include <linux/blkdev.h>#include <linux/blkpg.h>#include <linux/genhd.h>#include <linux/hdreg.h>#define PRINTK printk//#define PRINTK(...) #define DEVICE_NAME "6410_ram_block"#define RAMBLOCK_SIZE (1024*1024)static int major;static DEFINE_SPINLOCK(s3c6410_ram_lock);static struct gendisk *s3c6410_ram_gendisk;static struct request_queue *ramblock_queue;static unsigned char *ramblock_buf;static void do_ram_blk_request(struct request_queue *queue){struct request *req;static int r_cnt = 0;static int w_cnt = 0;while((req = blk_fetch_request(queue))){int err = 0;unsigned long offset = blk_rq_pos(req) << 9;//addressunsigned long len = blk_rq_cur_bytes(req);//lenif (rq_data_dir(req) == READ){printk("do_ramblock_request read %d\n", ++r_cnt);memcpy(req->buffer, ramblock_buf+offset, len);}else{printk("do_ramblock_request write %d\n", ++w_cnt);memcpy(ramblock_buf+offset, req->buffer, len);}if (!__blk_end_request_cur(req, err))req = blk_fetch_request(queue);}PRINTK(KERN_ALERT"do_ram_blk_request!\n");}static int ram_blk_getgeo(struct block_device *block_device, struct hd_geometry *hd_geometry){hd_geometry->heads     = 2;//fdiskhd_geometry->cylinders = 32;hd_geometry->sectors   = RAMBLOCK_SIZE/2/32/512;PRINTK(KERN_ALERT"ram_blk_getgeo!\n");return 0;}static const struct block_device_operations s3c6410_ram_fops ={.owner = THIS_MODULE,.getgeo = ram_blk_getgeo,};static int blk_driver_init(void)  {   int ret;ret = -EBUSY;   if ((major = register_blkdev(0, DEVICE_NAME)) < 0)goto out_err;ret = -ENOMEM;s3c6410_ram_gendisk = alloc_disk(16);//this will alloc minorsif (!s3c6410_ram_gendisk)goto out_err;ramblock_queue = blk_init_queue(do_ram_blk_request, &s3c6410_ram_lock);  if (!ramblock_queue)goto out_err;s3c6410_ram_gendisk->major = major;s3c6410_ram_gendisk->first_minor = 2;s3c6410_ram_gendisk->fops = &s3c6410_ram_fops;s3c6410_ram_gendisk->queue = ramblock_queue;sprintf(s3c6410_ram_gendisk->disk_name, "my_blk_ram");ret = -ENOMEM;  ramblock_buf = kzalloc(RAMBLOCK_SIZE, GFP_KERNEL);//this will do handware settings, as we only do some request memif(!ramblock_buf){       goto out_err;     }add_disk(s3c6410_ram_gendisk);PRINTK(KERN_ALERT"init!\n");return 0;out_err:if(major)unregister_blkdev(major, DEVICE_NAME);if (s3c6410_ram_gendisk)put_disk(s3c6410_ram_gendisk);if(ramblock_buf)kfree(ramblock_buf);if(ramblock_queue)blk_cleanup_queue(ramblock_queue);return ret;}  static int blk_driver_exit(void)  {   if(major)unregister_blkdev(major, DEVICE_NAME);if (s3c6410_ram_gendisk){del_gendisk(s3c6410_ram_gendisk);put_disk(s3c6410_ram_gendisk);}if(ramblock_buf)kfree(ramblock_buf);if(ramblock_queue)blk_cleanup_queue(ramblock_queue);PRINTK(KERN_ALERT"exit!\n");return 0;  }   module_init(blk_driver_init);  module_exit(blk_driver_exit);MODULE_LICENSE("GPL");  MODULE_DESCRIPTION("S3C6410 block device driver");MODULE_AUTHOR("Books, <[e-mail]>");