mtdchar.c

基于linux-2.6.28的mtd驱动

/*
 * Character-device access to raw MTD devices.
 *
 */

#include <linux/device.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/smp_lock.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;

	device_create(mtd_class, NULL, MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
		      NULL, "mtd%d", mtd->index);

	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;

	device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2));
	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;
	int ret = 0;
	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 & FMODE_WRITE) && (minor & 1))
		return -EACCES;

	lock_kernel();
	mtd = get_mtd_device(NULL, devnum);

	if (IS_ERR(mtd)) {
		ret = PTR_ERR(mtd);
		goto out;
	}

	if (MTD_ABSENT == mtd->type) {
		put_mtd_device(mtd);
		ret = -ENODEV;
		goto out;
	}

	/* You can't open it RW if it's not a writeable device */
	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
		put_mtd_device(mtd);
		ret = -EACCES;
		goto out;
	}

	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
	if (!mfi) {
		put_mtd_device(mtd);
		ret = -ENOMEM;
		goto out;
	}
	mfi->mtd = mtd;
	file->private_data = mfi;

out:
	unlock_kernel();
	return ret;
} /* 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");

	/* Only sync if opened RW */
	if ((file->f_mode & FMODE_WRITE) && 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);
}

#ifdef CONFIG_HAVE_MTD_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:
	{
		uint32_t ur_idx;
		struct mtd_erase_region_info *kr;