int scull_init_module(void)
{
int result, i;
dev_t dev = 0;
/*
* Get a range of minor numbers to work with, asking for a dynamic
* major unless directed otherwise at load time.
*/
if (scull_major) {
dev = MKDEV(scull_major, scull_minor);
result = register_chrdev_region(dev, scull_nr_devs, "scull");
} else {
result = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs,
"scull");
scull_major = MAJOR(dev);
}
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return result;
}
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail; /* Make this more graceful */
}
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));
/* Initialize each device. */
for (i = 0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
#ifndef init_MUTE
sema_init(&scull_devices[i].sem, 1);
#else
init_MUTEX(&scull_devices[i].sem);
#endif
scull_setup_cdev(&scull_devices[i], i);
}
/* At this point call the init function for any friend device */
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
dev += scull_p_init(dev);
dev += scull_access_init(dev);
#ifdef SCULL_DEBUG /* only when debugging */
scull_create_proc();
#endif
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}
int init_module(void)
{
int result, i;
/*
* Register your major, and accept a dynamic number
*/
result = register_chrdev(scull_major, "scull", &scull_fops);
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n",scull_major);
return result;
}
if (scull_major == 0) scull_major = result; /* dynamic */
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof (Scull_Dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail_malloc;
}
memset(scull_devices, 0, scull_nr_devs * sizeof (Scull_Dev));
for (i=0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
}
/* At this point call the init function for any friend device */
if ( (result = scull_p_init()) )
goto fail_pipe;
if ( (result = scull_access_init()) )
goto fail_access;
/* ... */
#ifndef SCULL_DEBUG
REGISTER_SYMTAB(NULL); /* otherwise, leave global symbols visible */
#endif
#ifdef SCULL_USE_PROC /* only when available */
/* this is the last line in init_module */
proc_register_dynamic(&proc_root, &scull_proc_entry);
#endif
return 0; /* succeed */
fail_access: scull_p_cleanup();
fail_pipe: kfree(scull_devices);
fail_malloc: unregister_chrdev(scull_major, "scull");
return result;
}
int scull_init_module(void)
{
int result, i;
#ifdef CONFIG_DEVFS_FS
/* If we have devfs, create /dev/scull to put files in there */
scull_devfs_dir = devfs_mk_dir(NULL, "scull", NULL);
if (!scull_devfs_dir) return -EBUSY; /* problem */
#else /* no devfs, do it the "classic" way */
/*
* Register your major, and accept a dynamic number. This is the
* first thing to do, in order to avoid releasing other module's
* fops in scull_cleanup_module()
*/
result = register_chrdev(scull_major, "scull", &scull_fops);
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n",scull_major);
return result;
}
if (scull_major == 0) scull_major = result; /* dynamic */
#endif /* CONFIG_DEVFS_FS */
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(Scull_Dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail;
}
memset(scull_devices, 0, scull_nr_devs * sizeof(Scull_Dev));
for (i=0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
sema_init(&scull_devices[i].sem, 1);
#ifdef CONFIG_DEVFS_FS
sprintf(devname, "%i", i);
devfs_register(scull_devfs_dir, devname,
DEVFS_FL_AUTO_DEVNUM,
0, 0, S_IFCHR | S_IRUGO | S_IWUGO,
&scull_fops,
scull_devices+i);
#endif
}
/* At this point call the init function for any friend device */
if ( (result = scull_p_init()) )
goto fail;
if ( (result = scull_access_init()) )
goto fail;
/* ... */
#ifndef SCULL_DEBUG
EXPORT_NO_SYMBOLS; /* otherwise, leave global symbols visible */
#endif
#ifdef SCULL_DEBUG /* only when debugging */
scull_create_proc();
#endif
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}
int scull_init_module(void)
{
int result, i;
dev_t dev = 0;
/*
* Get a range of minor numbers to work with, asking for a dynamic
* major unless directed otherwise at load time.
* 根据scull_major的值是否为0,分别采用静态分配或动态分配
* scull_major为主设备编号,在scull中初始定义为 #define SCULL_MAJOR 0,如果用户通过命令行参数给major赋 >0 的值,则采取静态分配
* scull_minor为从设备编号
*/
printk(KERN_ALERT "Debug by andrea:scull_init_module()/n");
if (scull_major) {
dev = MKDEV(scull_major, scull_minor);
/*
* 静态分配设备编号
*/
result = register_chrdev_region(dev, scull_nr_devs, "scull");
} else {
/*
* 动态分配设备编号
*/
result = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs,
"scull");
scull_major = MAJOR(dev);
}
/*分配设备编号出错*/
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return result;
}
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
/*
* 为每一个设备分配内存空间
* scull_nr_devs 默认为4 ,即默认创建4个scull设备, 在scull.h 定义 define SCULL_NR_DEVS 4
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail; /* Make this more graceful */
}
/*
* 将scull_devices分配的内存清零
*/
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));
/* Initialize each device. */
/*
* 初始化 scull_nr_dev个 scull_dev结构体, 即scull_nr_dev个scull_dev设备
* scull_devices[i].qset代表当前scull设备中每一个qset的data域指向的数组有SCULL_QSET(默认1000)个指针
* scull_devices[i].quantum代表当前scull设备中每一个qset中上面的数组指向的量子有SCULL_QUANTUM(默认4000)个字节
*/
for (i = 0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
/* init_MUTEX(&scull_devices[i].sem);*/
sema_init(&scull_devices[i].sem,1);
/*
* 调用了scull_setup_cdev函数对相应scull设备进行设置
*/
scull_setup_cdev(&scull_devices[i], i);
}
/* At this point call the init function for any friend device */
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
dev += scull_p_init(dev);
dev += scull_access_init(dev);
#ifdef SCULL_DEBUG /* only when debugging */
scull_create_proc();
#endif
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}
/*[Tag000]
* 当模块加载时，调用；但是为什么要放在最后来实现他呢，看到Tag002时，你应该就明白了；
*/
int scull_init_module(void)
{
int result, i;
dev_t dev = 0;
/* [Tag001] */
/* [1]分配设备编号 */
/*
* Get a range of minor numbers to work with, asking for a dynamic
* major unless directed otherwise at load time.
*/
if (scull_major) { /* 预先自己指定了主设备号 */
dev = MKDEV(scull_major, scull_minor); /* 利用主设备号,找到设备编号给方法1用 */
result = register_chrdev_region(dev, scull_nr_devs, "scull");
} else { /* 动态自己生成设备编号,然后再利用设备编号得到主设备号;
记住如果用这个方法那么就要后建设备文件了,因为不能提前知道主号
当然也可以利用ldd3书中提供的脚本,巨方便&&通用 */
result = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs,
"scull");
scull_major = MAJOR(dev);
}
if (result < 0) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return result;
}
/*[2]设备对象实例化*/
/*
* allocate the devices -- we can't have them static, as the number
* can be specified at load time
*/
scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_devices) {
result = -ENOMEM;
goto fail; /* Make this more graceful */
}
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));
/* [3]在这里初始化设备用了2.6的新方法,在scull_setup_cdev里完成 */
/* Initialize each device. */
for (i = 0; i < scull_nr_devs; i++) {
scull_devices[i].quantum = scull_quantum; /* 可以根据自己insmod时传参
来自己改变量子和量子集(指针数组)的大小 */
scull_devices[i].qset = scull_qset;
init_MUTEX(&scull_devices[i].sem);
scull_setup_cdev(&scull_devices[i], i); /* 在分别完主设备编号后goto Tag002 设备注册 */
}
/* At this point call the init function for any friend device */
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
dev += scull_p_init(dev);
dev += scull_access_init(dev);
#ifdef SCULL_DEBUG /* only when debugging */
scull_create_proc();
#endif
return 0; /* succeed */
fail:
scull_cleanup_module();
return result;
}