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remarkable-linux/drivers/mtd/mtdchar.c
Thomas Gleixner 8593fbc68b [MTD] Rework the out of band handling completely 
Hopefully the last iteration on this!

The handling of out of band data on NAND was accompanied by tons of fruitless
discussions and halfarsed patches to make it work for a particular
problem. Sufficiently annoyed by I all those "I know it better" mails and the
resonable amount of discarded "it solves my problem" patches, I finally decided
to go for the big rework. After removing the _ecc variants of mtd read/write
functions the solution to satisfy the various requirements was to refactor the
read/write _oob functions in mtd.

The major change is that read/write_oob now takes a pointer to an operation
descriptor structure "struct mtd_oob_ops".instead of having a function with at
least seven arguments.

read/write_oob which should probably renamed to a more descriptive name, can do
the following tasks:

- read/write out of band data
- read/write data content and out of band data
- read/write raw data content and out of band data (ecc disabled)

struct mtd_oob_ops has a mode field, which determines the oob handling mode.

Aside of the MTD_OOB_RAW mode, which is intended to be especially for
diagnostic purposes and some internal functions e.g. bad block table creation,
the other two modes are for mtd clients:

MTD_OOB_PLACE puts/gets the given oob data exactly to/from the place which is
described by the ooboffs and ooblen fields of the mtd_oob_ops strcuture. It's
up to the caller to make sure that the byte positions are not used by the ECC
placement algorithms.

MTD_OOB_AUTO puts/gets the given oob data automaticaly to/from the places in
the out of band area which are described by the oobfree tuples in the ecclayout
data structre which is associated to the devicee.

The decision whether data plus oob or oob only handling is done depends on the
setting of the datbuf member of the data structure. When datbuf == NULL then
the internal read/write_oob functions are selected, otherwise the read/write
data routines are invoked.

Tested on a few platforms with all variants. Please be aware of possible
regressions for your particular device / application scenario

Disclaimer: Any whining will be ignored from those who just contributed "hot
air blurb" and never sat down to tackle the underlying problem of the mess in
the NAND driver grown over time and the big chunk of work to fix up the
existing users. The problem was not the holiness of the existing MTD
interfaces. The problems was the lack of time to go for the big overhaul. It's
easy to add more mess to the existing one, but it takes alot of effort to go
for a real solution.

Improvements and bugfixes are welcome!

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2006-05-29 15:06:51 +02:00

715 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/config.h>
#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,
};
/*
* We use file->private_data to store a pointer to the MTDdevice.
* Since alighment is at least 32 bits, we have 2 bits free for OTP
* modes as well.
*/
#define TO_MTD(file) (struct mtd_info *)((long)((file)->private_data) & ~3L)
#define MTD_MODE_OTP_FACT 1
#define MTD_MODE_OTP_USER 2
#define MTD_MODE(file) ((long)((file)->private_data) & 3)
#define SET_MTD_MODE(file, mode) \
do { long __p = (long)((file)->private_data); \
(file)->private_data = (void *)((__p & ~3L) | mode); } while (0)
static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
{
struct mtd_info *mtd = TO_MTD(file);
switch (orig) {
case 0:
/* SEEK_SET */
break;
case 1:
/* SEEK_CUR */
offset += file->f_pos;
break;
case 2:
/* 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;
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 */
/*====================================================================*/
static int mtd_close(struct inode *inode, struct file *file)
{
struct mtd_info *mtd;
DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
mtd = TO_MTD(file);
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
static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
{
struct mtd_info *mtd = TO_MTD(file);
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 (MTD_MODE(file)) {
case MTD_MODE_OTP_FACT:
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;
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 !
* Userspace software which accesses NAND this way
* must be aware of the fact that it deals with NAND
*/
if (!ret || (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_info *mtd = TO_MTD(file);
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 (MTD_MODE(file)) {
case MTD_MODE_OTP_FACT:
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;
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);
}
static int mtd_ioctl(struct inode *inode, struct file *file,
u_int cmd, u_long arg)
{
struct mtd_info *mtd = TO_MTD(file);
void __user *argp = (void __user *)arg;
int ret = 0;
u_long size;
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:
if (copy_to_user(argp, mtd, 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.len = buf.length;
ops.ooblen = mtd->oobsize;
ops.ooboffs = buf.start & (mtd->oobsize - 1);
ops.datbuf = NULL;
ops.mode = MTD_OOB_PLACE;
if (ops.ooboffs && ops.len > (ops.ooblen - 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.retlen,
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.len = buf.length;
ops.ooblen = mtd->oobsize;
ops.ooboffs = buf.start & (mtd->oobsize - 1);
ops.datbuf = NULL;
ops.mode = MTD_OOB_PLACE;
if (ops.ooboffs && ops.len > (ops.ooblen - 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.retlen, (uint32_t __user *)argp))
ret = -EFAULT;
else if (ops.retlen && copy_to_user(buf.ptr, ops.oobbuf,
ops.retlen))
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));
if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
return -EFAULT;
break;
}
case ECCGETLAYOUT:
if (!mtd->ecclayout)
return -EOPNOTSUPP;
if (copy_to_user(argp, &mtd->ecclayout,
sizeof(struct nand_ecclayout)))
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;
SET_MTD_MODE(file, 0);
switch (mode) {
case MTD_OTP_FACTORY:
if (!mtd->read_fact_prot_reg)
ret = -EOPNOTSUPP;
else
SET_MTD_MODE(file, MTD_MODE_OTP_FACT);
break;
case MTD_OTP_USER:
if (!mtd->read_fact_prot_reg)
ret = -EOPNOTSUPP;
else
SET_MTD_MODE(file, MTD_MODE_OTP_USER);
break;
default:
ret = -EINVAL;
case MTD_OTP_OFF:
break;
}
file->f_pos = 0;
break;
}
case OTPGETREGIONCOUNT:
case OTPGETREGIONINFO:
{
struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ret = -EOPNOTSUPP;
switch (MTD_MODE(file)) {
case MTD_MODE_OTP_FACT:
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;
}
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 (MTD_MODE(file) != 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
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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