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7014568bad
linux/drivers/mtd/mtdchar.c
Vitaly Wool 7014568bad [MTD] [NAND] remove len/ooblen confusion. 
As was discussed between Ricard Wanderlöf, David Woodhouse, Artem 
Bityutskiy and me, the current API for reading/writing OOB is confusing. 

The thing that introduces confusion is the need to specify ops.len 
together with ops.ooblen for reads/writes that concern only OOB not data 
area. So, ops.len is overloaded: when ops.datbuf != NULL it serves to 
specify the length of the data read, and when ops.datbuf == NULL, it 
serves to specify the full OOB read length.

The patch inlined below is the slightly updated version of the previous 
patch serving the same purpose, but with the new Artem's comments taken 
into account.

Artem, BTW, thanks a lot for your valuable input!

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-11-28 22:39:03 +00:00

806 lines
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/*
* $Id: mtdchar.c,v 1.76 2005/11/07 11:14:20 gleixner Exp $
*
* Character-device access to raw MTD devices.
*
*/
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/compatmac.h>
#include <asm/uaccess.h>
static struct class *mtd_class;
static void mtd_notify_add(struct mtd_info* mtd)
{
if (!mtd)
return;
class_device_create(mtd_class, NULL, MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
NULL, "mtd%d", mtd->index);
class_device_create(mtd_class, NULL,
MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1),
NULL, "mtd%dro", mtd->index);
}
static void mtd_notify_remove(struct mtd_info* mtd)
{
if (!mtd)
return;
class_device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2));
class_device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1));
}
static struct mtd_notifier notifier = {
.add = mtd_notify_add,
.remove = mtd_notify_remove,
};
/*
* Data structure to hold the pointer to the mtd device as well
* as mode information ofr various use cases.
*/
struct mtd_file_info {
struct mtd_info *mtd;
enum mtd_file_modes mode;
};
static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
{
struct mtd_file_info *mfi = file->private_data;
struct mtd_info *mtd = mfi->mtd;
switch (orig) {
case SEEK_SET:
break;
case SEEK_CUR:
offset += file->f_pos;
break;
case SEEK_END:
offset += mtd->size;
break;
default:
return -EINVAL;
}
if (offset >= 0 && offset <= mtd->size)
return file->f_pos = offset;
return -EINVAL;
}
static int mtd_open(struct inode *inode, struct file *file)
{
int minor = iminor(inode);
int devnum = minor >> 1;
struct mtd_info *mtd;
struct mtd_file_info *mfi;
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;
}
/* 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;
}
mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
if (!mfi) {
put_mtd_device(mtd);
return -ENOMEM;
}
mfi->mtd = mtd;
file->private_data = mfi;
return 0;
} /* mtd_open */
/*====================================================================*/
static int mtd_close(struct inode *inode, struct file *file)
{
struct mtd_file_info *mfi = file->private_data;
struct mtd_info *mtd = mfi->mtd;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
if (mtd->sync)
mtd->sync(mtd);
put_mtd_device(mtd);
file->private_data = NULL;
kfree(mfi);
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
static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
{
struct mtd_file_info *mfi = file->private_data;
struct mtd_info *mtd = mfi->mtd;
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 */
if (count > MAX_KMALLOC_SIZE)
kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
else
kbuf=kmalloc(count, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
while (count) {
if (count > MAX_KMALLOC_SIZE)
len = MAX_KMALLOC_SIZE;
else
len = count;
switch (mfi->mode) {
case MTD_MODE_OTP_FACTORY:
ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
break;
case MTD_MODE_OTP_USER:
ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
break;
case MTD_MODE_RAW:
{
struct mtd_oob_ops ops;
ops.mode = MTD_OOB_RAW;
ops.datbuf = kbuf;
ops.oobbuf = NULL;
ops.len = len;
ret = mtd->read_oob(mtd, *ppos, &ops);
retlen = ops.retlen;
break;
}
default:
ret = mtd->read(mtd, *ppos, len, &retlen, kbuf);
}
/* Nand returns -EBADMSG on ecc errors, but it returns
* the data. For our userspace tools it is important
* to dump areas with ecc errors !
* For kernel internal usage it also might return -EUCLEAN
* to signal the caller that a bitflip has occured and has
* been corrected by the ECC algorithm.
* Userspace software which accesses NAND this way
* must be aware of the fact that it deals with NAND
*/
if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {
*ppos += retlen;
if (copy_to_user(buf, kbuf, retlen)) {
kfree(kbuf);
return -EFAULT;
}
else
total_retlen += retlen;
count -= retlen;
buf += retlen;
if (retlen == 0)
count = 0;
}
else {
kfree(kbuf);
return ret;
}
}
kfree(kbuf);
return total_retlen;
} /* mtd_read */
static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
{
struct mtd_file_info *mfi = file->private_data;
struct mtd_info *mtd = mfi->mtd;
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;
if (count > MAX_KMALLOC_SIZE)
kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
else
kbuf=kmalloc(count, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
while (count) {
if (count > MAX_KMALLOC_SIZE)
len = MAX_KMALLOC_SIZE;
else
len = count;
if (copy_from_user(kbuf, buf, len)) {
kfree(kbuf);
return -EFAULT;
}
switch (mfi->mode) {
case MTD_MODE_OTP_FACTORY:
ret = -EROFS;
break;
case MTD_MODE_OTP_USER:
if (!mtd->write_user_prot_reg) {
ret = -EOPNOTSUPP;
break;
}
ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
break;
case MTD_MODE_RAW:
{
struct mtd_oob_ops ops;
ops.mode = MTD_OOB_RAW;
ops.datbuf = kbuf;
ops.oobbuf = NULL;
ops.len = len;
ret = mtd->write_oob(mtd, *ppos, &ops);
retlen = ops.retlen;
break;
}
default:
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 */
/*======================================================================
IOCTL calls for getting device parameters.
======================================================================*/
static void mtdchar_erase_callback (struct erase_info *instr)
{
wake_up((wait_queue_head_t *)instr->priv);
}
#if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
{
struct mtd_info *mtd = mfi->mtd;
int ret = 0;
switch (mode) {
case MTD_OTP_FACTORY:
if (!mtd->read_fact_prot_reg)
ret = -EOPNOTSUPP;
else
mfi->mode = MTD_MODE_OTP_FACTORY;
break;
case MTD_OTP_USER:
if (!mtd->read_fact_prot_reg)
ret = -EOPNOTSUPP;
else
mfi->mode = MTD_MODE_OTP_USER;
break;
default:
ret = -EINVAL;
case MTD_OTP_OFF:
break;
}
return ret;
}
#else
# define otp_select_filemode(f,m) -EOPNOTSUPP
#endif
static int mtd_ioctl(struct inode *inode, struct file *file,
u_int cmd, u_long arg)
{
struct mtd_file_info *mfi = file->private_data;
struct mtd_info *mtd = mfi->mtd;
void __user *argp = (void __user *)arg;
int ret = 0;
u_long size;
struct mtd_info_user info;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
if (cmd & IOC_IN) {
if (!access_ok(VERIFY_READ, argp, size))
return -EFAULT;
}
if (cmd & IOC_OUT) {
if (!access_ok(VERIFY_WRITE, argp, size))
return -EFAULT;
}
switch (cmd) {
case MEMGETREGIONCOUNT:
if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
return -EFAULT;
break;
case MEMGETREGIONINFO:
{
struct region_info_user ur;
if (copy_from_user(&ur, argp, sizeof(struct region_info_user)))
return -EFAULT;
if (ur.regionindex >= mtd->numeraseregions)
return -EINVAL;
if (copy_to_user(argp, &(mtd->eraseregions[ur.regionindex]),
sizeof(struct mtd_erase_region_info)))
return -EFAULT;
break;
}
case MEMGETINFO:
info.type = mtd->type;
info.flags = mtd->flags;
info.size = mtd->size;
info.erasesize = mtd->erasesize;
info.writesize = mtd->writesize;
info.oobsize = mtd->oobsize;
info.ecctype = mtd->ecctype;
info.eccsize = mtd->eccsize;
if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
return -EFAULT;
break;
case MEMERASE:
{
struct erase_info *erase;
if(!(file->f_mode & 2))
return -EPERM;
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, argp,
sizeof(struct erase_info_user))) {
kfree(erase);
return -EFAULT;
}
erase->mtd = mtd;
erase->callback = mtdchar_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;
struct mtd_oob_ops ops;
if(!(file->f_mode & 2))
return -EPERM;
if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
return -EFAULT;
if (buf.length > 4096)
return -EINVAL;
if (!mtd->write_oob)
ret = -EOPNOTSUPP;
else
ret = access_ok(VERIFY_READ, buf.ptr,
buf.length) ? 0 : EFAULT;
if (ret)
return ret;
ops.ooblen = buf.length;
ops.ooboffs = buf.start & (mtd->oobsize - 1);
ops.datbuf = NULL;
ops.mode = MTD_OOB_PLACE;
if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
return -EINVAL;
ops.oobbuf = kmalloc(buf.length, GFP_KERNEL);
if (!ops.oobbuf)
return -ENOMEM;
if (copy_from_user(ops.oobbuf, buf.ptr, buf.length)) {
kfree(ops.oobbuf);
return -EFAULT;
}
buf.start &= ~(mtd->oobsize - 1);
ret = mtd->write_oob(mtd, buf.start, &ops);
if (copy_to_user(argp + sizeof(uint32_t), &ops.oobretlen,
sizeof(uint32_t)))
ret = -EFAULT;
kfree(ops.oobbuf);
break;
}
case MEMREADOOB:
{
struct mtd_oob_buf buf;
struct mtd_oob_ops ops;
if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
return -EFAULT;
if (buf.length > 4096)
return -EINVAL;
if (!mtd->read_oob)
ret = -EOPNOTSUPP;
else
ret = access_ok(VERIFY_WRITE, buf.ptr,
buf.length) ? 0 : -EFAULT;
if (ret)
return ret;
ops.ooblen = buf.length;
ops.ooboffs = buf.start & (mtd->oobsize - 1);
ops.datbuf = NULL;
ops.mode = MTD_OOB_PLACE;
if (ops.ooboffs && ops.len > (mtd->oobsize - ops.ooboffs))
return -EINVAL;
ops.oobbuf = kmalloc(buf.length, GFP_KERNEL);
if (!ops.oobbuf)
return -ENOMEM;
buf.start &= ~(mtd->oobsize - 1);
ret = mtd->read_oob(mtd, buf.start, &ops);
if (put_user(ops.oobretlen, (uint32_t __user *)argp))
ret = -EFAULT;
else if (ops.oobretlen && copy_to_user(buf.ptr, ops.oobbuf,
ops.oobretlen))
ret = -EFAULT;
kfree(ops.oobbuf);
break;
}
case MEMLOCK:
{
struct erase_info_user info;
if (copy_from_user(&info, argp, sizeof(info)))
return -EFAULT;
if (!mtd->lock)
ret = -EOPNOTSUPP;
else
ret = mtd->lock(mtd, info.start, info.length);
break;
}
case MEMUNLOCK:
{
struct erase_info_user info;
if (copy_from_user(&info, argp, sizeof(info)))
return -EFAULT;
if (!mtd->unlock)
ret = -EOPNOTSUPP;
else
ret = mtd->unlock(mtd, info.start, info.length);
break;
}
/* Legacy interface */
case MEMGETOOBSEL:
{
struct nand_oobinfo oi;
if (!mtd->ecclayout)
return -EOPNOTSUPP;
if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
return -EINVAL;
oi.useecc = MTD_NANDECC_AUTOPLACE;
memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
sizeof(oi.oobfree));
oi.eccbytes = mtd->ecclayout->eccbytes;
if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
return -EFAULT;
break;
}
case MEMGETBADBLOCK:
{
loff_t offs;
if (copy_from_user(&offs, argp, sizeof(loff_t)))
return -EFAULT;
if (!mtd->block_isbad)
ret = -EOPNOTSUPP;
else
return mtd->block_isbad(mtd, offs);
break;
}
case MEMSETBADBLOCK:
{
loff_t offs;
if (copy_from_user(&offs, argp, sizeof(loff_t)))
return -EFAULT;
if (!mtd->block_markbad)
ret = -EOPNOTSUPP;
else
return mtd->block_markbad(mtd, offs);
break;
}
#if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
case OTPSELECT:
{
int mode;
if (copy_from_user(&mode, argp, sizeof(int)))
return -EFAULT;
mfi->mode = MTD_MODE_NORMAL;
ret = otp_select_filemode(mfi, mode);
file->f_pos = 0;
break;
}
case OTPGETREGIONCOUNT:
case OTPGETREGIONINFO:
{
struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ret = -EOPNOTSUPP;
switch (mfi->mode) {
case MTD_MODE_OTP_FACTORY:
if (mtd->get_fact_prot_info)
ret = mtd->get_fact_prot_info(mtd, buf, 4096);
break;
case MTD_MODE_OTP_USER:
if (mtd->get_user_prot_info)
ret = mtd->get_user_prot_info(mtd, buf, 4096);
break;
default:
break;
}
if (ret >= 0) {
if (cmd == OTPGETREGIONCOUNT) {
int nbr = ret / sizeof(struct otp_info);
ret = copy_to_user(argp, &nbr, sizeof(int));
} else
ret = copy_to_user(argp, buf, ret);
if (ret)
ret = -EFAULT;
}
kfree(buf);
break;
}
case OTPLOCK:
{
struct otp_info info;
if (mfi->mode != MTD_MODE_OTP_USER)
return -EINVAL;
if (copy_from_user(&info, argp, sizeof(info)))
return -EFAULT;
if (!mtd->lock_user_prot_reg)
return -EOPNOTSUPP;
ret = mtd->lock_user_prot_reg(mtd, info.start, info.length);
break;
}
#endif
case ECCGETLAYOUT:
{
if (!mtd->ecclayout)
return -EOPNOTSUPP;
if (copy_to_user(argp, mtd->ecclayout,
sizeof(struct nand_ecclayout)))
return -EFAULT;
break;
}
case ECCGETSTATS:
{
if (copy_to_user(argp, &mtd->ecc_stats,
sizeof(struct mtd_ecc_stats)))
return -EFAULT;
break;
}
case MTDFILEMODE:
{
mfi->mode = 0;
switch(arg) {
case MTD_MODE_OTP_FACTORY:
case MTD_MODE_OTP_USER:
ret = otp_select_filemode(mfi, arg);
break;
case MTD_MODE_RAW:
if (!mtd->read_oob || !mtd->write_oob)
return -EOPNOTSUPP;
mfi->mode = arg;
case MTD_MODE_NORMAL:
break;
default:
ret = -EINVAL;
}
file->f_pos = 0;
break;
}
default:
ret = -ENOTTY;
}
return ret;
} /* memory_ioctl */
static struct file_operations mtd_fops = {
.owner = THIS_MODULE,
.llseek = mtd_lseek,
.read = mtd_read,
.write = mtd_write,
.ioctl = mtd_ioctl,
.open = mtd_open,
.release = mtd_close,
};
static int __init init_mtdchar(void)
{
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;
}
mtd_class = class_create(THIS_MODULE, "mtd");
if (IS_ERR(mtd_class)) {
printk(KERN_ERR "Error creating mtd class.\n");
unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
return PTR_ERR(mtd_class);
}
register_mtd_user(&notifier);
return 0;
}
static void __exit cleanup_mtdchar(void)
{
unregister_mtd_user(&notifier);
class_destroy(mtd_class);
unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
}
module_init(init_mtdchar);
module_exit(cleanup_mtdchar);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Direct character-device access to MTD devices");
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