分类: LINUX
2012-06-03 15:20:22
MTD字符设备的文件
MTD字符设备的notifier
static struct mtd_notifier notifier = {
add: mtd_notify_add,
remove: mtd_notify_remove,
};
格式:
static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
注释:
无
功能:
置MTD字符设备的指针
说明:
无
参数:
file:MTD字符设备文件
offset:偏移
orig:设置方式
返回:
成功:返回当前指针位置
设置方式无效:返回-EINVAL
调用:
无
被调用:
注册进mtd_fops结构
源代码:
{
struct mtd_info *mtd=(struct mtd_info *)file->private_data;
switch (orig) {
case 0:
/* SEEK_SET */
file->f_pos = offset;
break;
case 1:
/* SEEK_CUR */
file->f_pos += offset;
break;
case 2:
/* SEEK_END */
file->f_pos =mtd->size + offset;
break;
default:
return -EINVAL;
}
if (file->f_pos < 0)
file->f_pos = 0;
else if (file->f_pos >= mtd->size)
file->f_pos = mtd->size - 1;
return file->f_pos;
}
格式:
static int mtd_open(struct inode *inode, struct file *file)
注释:
无
功能:
打开一个MTD字符设备
说明:
devnum=minor>>2(参看Documentations/devices.txt),
进行安全性检查,
调用get_mtd_device获取MTD设备,并将file->private_data指向它
参数:
inode:FIXME
file:是系统提供给MTD字符设备用于传递参数的file结构,此函数中它的private_data
成员被指向原始设备层的MTD设备
返回:
成功:返回0
失败:返回错误码
调用:
get_mtd_device()获得原始设备层的MTD设备
被调用:
注册进mtd_fops结构
源代码:
{
int minor = MINOR(inode->i_rdev);
int devnum = minor >> 1;
struct mtd_info *mtd;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_open/n");
if (devnum >= MAX_MTD_DEVICES)
return -ENODEV;
/* You can't open the RO devices RW */
if ((file->f_mode & 2) && (minor & 1))
return -EACCES;
mtd = get_mtd_device(NULL, devnum);
if (!mtd)
return -ENODEV;
if (MTD_ABSENT == mtd->type) {
put_mtd_device(mtd);
return -ENODEV;
}
file->private_data = mtd;
/* You can't open it RW if it's not a writeable device */
if ((file->f_mode & 2) && !(mtd->flags & MTD_WRITEABLE)) {
put_mtd_device(mtd);
return -EACCES;
}
return 0;
} /* mtd_open */
格式:
static int mtd_close(struct inode *inode, struct file *file)
注释:
无
功能:
关闭一个MTD字符设备
说明:
调用mtd_info->sync()同步MTD设备,
调用put_mtd_device()返还MTD设备
参数:
inode:FIXME
file:无用
返回:
返回0
调用:
mtd_info->sync()同步MTD设备
put_mtd_device()返还MTD设备
被调用:
被注册进mtd_fops结构
源代码:
{
struct mtd_info *mtd;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_close/n");
mtd = (struct mtd_info *)file->private_data;
if (mtd->sync)
mtd->sync(mtd);
put_mtd_device(mtd);
return 0;
} /* mtd_close */
/* FIXME: This _really_ needs to die. In 2.5, we should lock the
userspace buffer down and use it directly with readv/writev.
*/
#define MAX_KMALLOC_SIZE 0x20000
格式:
static ssize_t mtd_read(struct file *file, char *buf, size_t count,loff_t *ppos)
注释:
无
功能:
MTD字符设备的写操作
说明:
当count>0时{
裁减本次操作大小len至min(MAX_KMALLOC_SIZE,count),
申请一块大小为MAX_KMALLOC_SIZE的内核空间kbuf,
调用mtd_info->read将MTD设备中的数据读入kbuf,
将kbuf中的数据拷贝到用户空间buf,
count自减
释放kbuf
}
参数:
file:系统给MTD字符设备驱动程序用于传递参数的file结构,此函数通过file得到下
层的MTD设备
buf:用户空间的指针,用于存放读取的数据
count:被读数据的长度
ppos:被读数据在MTD设备中的位置
返回:
成功:返回实际读取数据的长度
失败:返回错误码
调用:
mtd_info->read()用于从MTD设备中读取数据
被调用:
被注册进mtd_fops结构
源代码:
{
struct mtd_info *mtd = (struct mtd_info *)file->private_data;
size_t retlen=0;
size_t total_retlen=0;
int ret=0;
int len;
char *kbuf;
DEBUG(MTD_DEBUG_LEVEL0,"MTD_read/n");
if (*ppos + count > mtd->size)
count = mtd->size - *ppos;
if (!count)
return 0;
/* FIXME: Use kiovec in 2.5 to lock down the user's buffers
and pass them directly to the MTD functions */
while (count) {
if (count > MAX_KMALLOC_SIZE)
len = MAX_KMALLOC_SIZE;
else
len = count;
kbuf=kmalloc(len,GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
ret = MTD_READ(mtd, *ppos, len, &retlen, kbuf);
if (!ret) {
*ppos += retlen;
if (copy_to_user(buf, kbuf, retlen)) {
kfree(kbuf);
return -EFAULT;
}
else
total_retlen += retlen;
count -= retlen;
buf += retlen;
}
else {
kfree(kbuf);
return ret;
}
kfree(kbuf);
}
return total_retlen;
} /* mtd_read */
格式:
static ssize_t mtd_write(struct file *file, const char *buf, size_t count,loff_t *ppos)
注释:
无
功能:
对MTD字符设备的写操作
说明:
当count>0时{
裁减本次操作大小len至min(MAX_KMALLOC_SIZE,count),
申请一块大小为MAX_KMALLOC_SIZE的内核空间kbuf,
将用户空间buf中的数据拷贝到kbuf,
调用mtd_info->write将kbuf中的数据读入MTD设备,
count自减
释放kbuf
}
参数:
file:系统给MTD字符设备驱动程序用于传递参数的file结构,此函数通过file得到下
层的MTD设备
buf:用户空间的指针,用于存放将要写入的数据
count:被写数据的长度
ppos:数据被写入MTD设备中的位置
返回:
成功:返回实际读取数据的长度
失败:返回错误码
调用:
mtd_info->write用于写入MTD设备
被调用:
被注册进mtd_fops结构
源代码:
{
struct mtd_info *mtd = (struct mtd_info *)file->private_data;
char *kbuf;
size_t retlen;
size_t total_retlen=0;
int ret=0;
int len;
DEBUG(MTD_DEBUG_LEVEL0,"MTD_write/n");
if (*ppos == mtd->size)
return -ENOSPC;
if (*ppos + count > mtd->size)
count = mtd->size - *ppos;
if (!count)
return 0;
while (count) {
if (count > MAX_KMALLOC_SIZE)
len = MAX_KMALLOC_SIZE;
else
len = count;
kbuf=kmalloc(len,GFP_KERNEL);
if (!kbuf) {
printk("kmalloc is null/n");
return -ENOMEM;
}
if (copy_from_user(kbuf, buf, len)) {
kfree(kbuf);
return -EFAULT;
}
ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
if (!ret) {
*ppos += retlen;
total_retlen += retlen;
count -= retlen;
buf += retlen;
}
else {
kfree(kbuf);
return ret;
}
kfree(kbuf);
}
return total_retlen;
} /* mtd_write */
格式:
static void mtd_erase_callback (struct erase_info *instr)
注释:
无
功能:
唤醒进程
说明:
在擦除进行完后被调用
参数:
instr:进行的擦除的erase_info结构
返回:
无
调用:
wake_up()
被调用:
在mtd_ioctl中被赋给erase_info->callback
源代码:
{
wake_up((wait_queue_head_t *)instr->priv);
}
格式:
static int mtd_ioctl(struct inode *inode, struct file *file, u_int cmd, u_long arg)
注释:
无
功能:
MTD字符设备的IO控制
说明:
根据cmd分别处理
参数:
inode:FIXME
file:传递参数的结构
cmd:IO控制的命令
arg:IO控制的参数
返回:
成功:返回0
失败:返回错误码
调用:
无
被调用:
注册进mtd_fops结构
源代码:
{
struct mtd_info *mtd = (struct mtd_info *)file->private_data;
int ret = 0;
u_long size;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl/n");
size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
if (cmd & IOC_IN) {
ret = verify_area(VERIFY_READ, (char *)arg, size);
if (ret) return ret;
}
if (cmd & IOC_OUT) {
ret = verify_area(VERIFY_WRITE, (char *)arg, size);
if (ret) return ret;
}
switch (cmd) {
case MEMGETREGIONCOUNT:
if (copy_to_user((int *) arg, &(mtd->numeraseregions), sizeof(int)))
return -EFAULT;
break;
case MEMGETREGIONINFO:
{
struct region_info_user ur;
if (copy_from_user( &ur,
(struct region_info_user *)arg,
sizeof(struct region_info_user))) {
return -EFAULT;
}
if (ur.regionindex >= mtd->numeraseregions)
return -EINVAL;
if (copy_to_user((struct mtd_erase_region_info *) arg,
&(mtd->eraseregions[ur.regionindex]),
sizeof(struct mtd_erase_region_info)))
return -EFAULT;
break;
}
case MEMGETINFO:
if (copy_to_user((struct mtd_info *)arg, mtd,
sizeof(struct mtd_info_user)))
return -EFAULT;
break;
case MEMERASE:
{
struct erase_info *erase=kmalloc(sizeof(struct erase_info),GFP_KERNEL);
if (!erase)
ret = -ENOMEM;
else {
wait_queue_head_t waitq;
DECLARE_WAITQUEUE(wait, current);
init_waitqueue_head(&waitq);
memset (erase,0,sizeof(struct erase_info));
if (copy_from_user(&erase->addr, (u_long *)arg,
2 * sizeof(u_long))) {
kfree(erase);
return -EFAULT;
}
erase->mtd = mtd;
erase->callback = mtd_erase_callback;
erase->priv = (unsigned long)&waitq;
/*
FIXME: Allow INTERRUPTIBLE. Which means
not having the wait_queue head on the stack.
If the wq_head is on the stack, and we
leave because we got interrupted, then the
wq_head is no longer there when the
callback routine tries to wake us up.
*/
ret = mtd->erase(mtd, erase);
if (!ret) {
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&waitq, &wait);
if (erase->state != MTD_ERASE_DONE &&
erase->state != MTD_ERASE_FAILED)
schedule();
remove_wait_queue(&waitq, &wait);
set_current_state(TASK_RUNNING);
ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
}
kfree(erase);
}
break;
}
case MEMWRITEOOB:
{
struct mtd_oob_buf buf;
void *databuf;
ssize_t retlen;
if (copy_from_user(&buf, (struct mtd_oob_buf *)arg, sizeof(struct mtd_oob_buf)))
return -EFAULT;
if (buf.length > 0x4096)
return -EINVAL;
if (!mtd->write_oob)
ret = -EOPNOTSUPP;
else
ret = verify_area(VERIFY_READ, (char *)buf.ptr, buf.length);
if (ret)
return ret;
databuf = kmalloc(buf.length, GFP_KERNEL);
if (!databuf)
return -ENOMEM;
if (copy_from_user(databuf, buf.ptr, buf.length)) {
kfree(databuf);
return -EFAULT;
}
ret = (mtd->write_oob)(mtd, buf.start, buf.length, &retlen, databuf);
if (copy_to_user((void *)arg + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
ret = -EFAULT;
kfree(databuf);
break;
}
case MEMREADOOB:
{
struct mtd_oob_buf buf;
void *databuf;
ssize_t retlen;
if (copy_from_user(&buf, (struct mtd_oob_buf *)arg, sizeof(struct mtd_oob_buf)))
return -EFAULT;
if (buf.length > 0x4096)
return -EINVAL;
if (!mtd->read_oob)
ret = -EOPNOTSUPP;
else
ret = verify_area(VERIFY_WRITE, (char *)buf.ptr, buf.length);
if (ret)
return ret;
databuf = kmalloc(buf.length, GFP_KERNEL);
if (!databuf)
return -ENOMEM;
ret = (mtd->read_oob)(mtd, buf.start, buf.length, &retlen, databuf);
if (copy_to_user((void *)arg + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
ret = -EFAULT;
else if (retlen && copy_to_user(buf.ptr, databuf, retlen))
ret = -EFAULT;
kfree(databuf);
break;
}
case MEMLOCK:
{
unsigned long adrs[2];
if (copy_from_user(adrs ,(void *)arg, 2* sizeof(unsigned long)))
return -EFAULT;
if (!mtd->lock)
ret = -EOPNOTSUPP;
else
ret = mtd->lock(mtd, adrs[0], adrs[1]);
break;
}
case MEMUNLOCK:
{
unsigned long adrs[2];
if (copy_from_user(adrs, (void *)arg, 2* sizeof(unsigned long)))
return -EFAULT;
if (!mtd->unlock)
ret = -EOPNOTSUPP;
else
ret = mtd->unlock(mtd, adrs[0], adrs[1]);
break;
}
default:
DEBUG(MTD_DEBUG_LEVEL0, "Invalid ioctl %x (MEMGETINFO = %x)/n", cmd, MEMGETINFO);
ret = -ENOTTY;
}
return ret;
} /* memory_ioctl */
MTD字符设备的操作函数结构
static struct file_operations mtd_fops = {
owner: THIS_MODULE,
llseek: mtd_lseek, /* lseek */
read: mtd_read, /* read */
write: mtd_write, /* write */
ioctl: mtd_ioctl, /* ioctl */
open: mtd_open, /* open */
release: mtd_close, /* release */
};
格式:
static int __init init_mtdchar(void)
注释:
无
功能:
初始化一个MTD字符设备(设备层)
说明:
如果定义了CONFIG_DEVFS_FS{
调用devfs_register_chrdev()注册MTD字符设备
调用register_mtd_user()将设备层MTD字符设备的notifier注册进原始设备层
}
否则调用register_chrdev()注册MTD字符设备
参数:
无
返回:
成功:返回0
注册失败:返回-EAGAIN
调用:
devfs_register_chrdev()或register_chrdev()注册字符设备
被调用:
__init
module_init
源代码:
{
#ifdef CONFIG_DEVFS_FS
if (devfs_register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops))
{
printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices./n",
MTD_CHAR_MAJOR);
return -EAGAIN;
}
devfs_dir_handle = devfs_mk_dir(NULL, "mtd", NULL);
register_mtd_user(¬ifier);
#else
if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops))
{
printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices./n",
MTD_CHAR_MAJOR);
return -EAGAIN;
}
#endif
return 0;
}
格式:
static void __exit cleanup_mtdchar(void)
注释:
无
功能:
清除MTD字符设备
说明:
如果定义了CONFIG_DEVFS_FS{
调用unregister_mtd_user()注销MTD字符设备的notifier,
调用devfs_unregister_chrdev()注销MTD字符设备
}
否则调用unregister_chrdev()注销MTD字符设备
参数:
无
返回:
无
调用:
unregister_chrdev()或devfs_unregister_chrdev()注销字符设备
被调用:
__exit
module_exit
源代码:
{
#ifdef CONFIG_DEVFS_FS
unregister_mtd_user(¬ifier);
devfs_unregister(devfs_dir_handle);
devfs_unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
#else
unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
#endif
}