/*
 * Copyright (C) 2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Author: Artem Bityutskiy
 *
 * MTD library.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>

#include <mtd/mtd-user.h>
#include <libmtd.h>
#include "common.h"

#define PROGRAM_NAME "libmtd"
#define MTD_DEV_MAJOR 90

int mtd_get_dev_info(const char *node, struct mtd_dev_info *mtd)
{
	struct stat st;
	struct mtd_info_user ui;
	int fd, ret;
	loff_t offs = 0;

	if (stat(node, &st))
		return sys_errmsg("cannot open \"%s\"", node);

	if (!S_ISCHR(st.st_mode)) {
		errno = EINVAL;
		return errmsg("\"%s\" is not a character device", node);
	}

	mtd->major = major(st.st_rdev);
	mtd->minor = minor(st.st_rdev);

	if (mtd->major != MTD_DEV_MAJOR) {
		errno = EINVAL;
		return errmsg("\"%s\" has major number %d, MTD devices have "
			      "major %d", node, mtd->major, MTD_DEV_MAJOR);
	}

	mtd->dev_num = mtd->minor / 2;
	mtd->writable = !(mtd->minor & 1);

	fd = open(node, O_RDWR);
	if (fd == -1)
		return sys_errmsg("cannot open \"%s\"", node);

	if (ioctl(fd, MEMGETINFO, &ui)) {
		sys_errmsg("MEMGETINFO ioctl request failed");
		goto out_close;
	}

	ret = ioctl(fd, MEMGETBADBLOCK, &offs);
	if (ret == -1) {
		if (errno != EOPNOTSUPP) {
			sys_errmsg("MEMGETBADBLOCK ioctl failed");
			goto out_close;
		}
		errno = 0;
		mtd->bb_allowed = 0;
	} else
		mtd->bb_allowed = 1;

	mtd->type = ui.type;
	mtd->size = ui.size;
	mtd->eb_size = ui.erasesize;
	mtd->min_io_size = ui.writesize;

	if (mtd->min_io_size <= 0) {
		errmsg("mtd%d (%s) has insane min. I/O unit size %d",
		       mtd->dev_num, node, mtd->min_io_size);
		goto out_close;
	}
	if (mtd->eb_size <= 0 || mtd->eb_size < mtd->min_io_size) {
		errmsg("mtd%d (%s) has insane eraseblock size %d",
		       mtd->dev_num, node, mtd->eb_size);
		goto out_close;
	}
	if (mtd->size <= 0 || mtd->size < mtd->eb_size) {
		errmsg("mtd%d (%s) has insane size %lld",
		       mtd->dev_num, node, mtd->size);
		goto out_close;
	}
	mtd->eb_cnt = mtd->size / mtd->eb_size;

	switch(mtd->type) {
	case MTD_ABSENT:
		errmsg("mtd%d (%s) is removable and is not present",
		       mtd->dev_num, node);
		goto out_close;
	case MTD_RAM:
		strcpy(mtd->type_str, "RAM-based");
		break;
	case MTD_ROM:
		strcpy(mtd->type_str, "ROM");
		break;
	case MTD_NORFLASH:
		strcpy(mtd->type_str, "NOR");
		break;
	case MTD_NANDFLASH:
		strcpy(mtd->type_str, "NAND");
		break;
	case MTD_DATAFLASH:
		strcpy(mtd->type_str, "DataFlash");
		break;
	case MTD_UBIVOLUME:
		strcpy(mtd->type_str, "UBI-emulated MTD");
		break;
	default:
		strcpy(mtd->type_str, "Unknown flash type");
		break;
	}

	if (ui.flags & MTD_WRITEABLE)
		mtd->writable = 1;

	close(fd);
	return 0;

out_close:
	close(fd);
	return -1;
}

int mtd_erase(const struct mtd_dev_info *mtd, int fd, int eb)
{
	struct erase_info_user ei;

	ei.start = eb * mtd->eb_size;;
	ei.length = mtd->eb_size;
	return ioctl(fd, MEMERASE, &ei);
}

int mtd_is_bad(const struct mtd_dev_info *mtd, int fd, int eb)
{
	int ret;
	loff_t seek;

	if (eb < 0 || eb >= mtd->eb_cnt) {
		errmsg("bad eraseblock number %d, mtd%d has %d eraseblocks",
		       eb, mtd->dev_num, mtd->eb_cnt);
		errno = EINVAL;
		return -1;
	}

	if (!mtd->bb_allowed)
		return 0;

	seek = (loff_t)eb * mtd->eb_size;
	ret = ioctl(fd, MEMGETBADBLOCK, &seek);
	if (ret == -1)
		return sys_errmsg("MEMGETBADBLOCK ioctl failed for "
				  "eraseblock %d (mtd%d)", eb, mtd->dev_num);
	return ret;
}

int mtd_mark_bad(const struct mtd_dev_info *mtd, int fd, int eb)
{
	int ret;
	loff_t seek;

	if (!mtd->bb_allowed) {
		errno = EINVAL;
		return -1;
	}

	if (eb < 0 || eb >= mtd->eb_cnt) {
		errmsg("bad eraseblock number %d, mtd%d has %d eraseblocks",
		       eb, mtd->dev_num, mtd->eb_cnt);
		errno = EINVAL;
		return -1;
	}

	seek = (loff_t)eb * mtd->eb_size;
	ret = ioctl(fd, MEMSETBADBLOCK, &seek);
	if (ret == -1)
		return sys_errmsg("MEMSETBADBLOCK ioctl failed for "
			          "eraseblock %d (mtd%d)", eb, mtd->dev_num);
	return 0;
}

int mtd_read(const struct mtd_dev_info *mtd, int fd, int eb, int offs,
	     void *buf, int len)
{
	int ret, rd = 0;
	off_t seek;

	if (eb < 0 || eb >= mtd->eb_cnt) {
		errmsg("bad eraseblock number %d, mtd%d has %d eraseblocks",
		       eb, mtd->dev_num, mtd->eb_cnt);
		errno = EINVAL;
		return -1;
	}
	if (offs < 0 || offs + len > mtd->eb_size) {
		errmsg("bad offset %d or length %d, mtd%d eraseblock size is %d",
		       offs, len, mtd->dev_num, mtd->eb_size);
		errno = EINVAL;
		return -1;
	}

	/* Seek to the beginning of the eraseblock */
	seek = (off_t)eb * mtd->eb_size + offs;
	if (lseek(fd, seek, SEEK_SET) != seek)
		return sys_errmsg("cannot seek mtd%d to offset %llu",
				  mtd->dev_num, (unsigned long long)seek);

	while (rd < len) {
		ret = read(fd, buf, len);
		if (ret < 0)
			return sys_errmsg("cannot read %d bytes from mtd%d (eraseblock %d, offset %d)",
					  len, mtd->dev_num, eb, offs);
		rd += ret;
	}

	return 0;
}

int mtd_write(const struct mtd_dev_info *mtd, int fd, int eb, int offs,
	      void *buf, int len)
{
	int ret;
	off_t seek;

	if (eb < 0 || eb >= mtd->eb_cnt) {
		errmsg("bad eraseblock number %d, mtd%d has %d eraseblocks",
		       eb, mtd->dev_num, mtd->eb_cnt);
		errno = EINVAL;
		return -1;
	}
	if (offs < 0 || offs + len > mtd->eb_size) {
		errmsg("bad offset %d or length %d, mtd%d eraseblock size is %d",
		       offs, len, mtd->dev_num, mtd->eb_size);
		errno = EINVAL;
		return -1;
	}
#if 0
	if (offs % mtd->subpage_size) {
		errmsg("write offset %d is not aligned to mtd%d min. I/O size %d",
		       offs, mtd->dev_num, mtd->subpage_size);
		errno = EINVAL;
		return -1;
	}
	if (len % mtd->subpage_size) {
		errmsg("write length %d is not aligned to mtd%d min. I/O size %d",
		       len, mtd->dev_num, mtd->subpage_size);
		errno = EINVAL;
		return -1;
	}
#endif

	/* Seek to the beginning of the eraseblock */
	seek = (off_t)eb * mtd->eb_size + offs;
	if (lseek(fd, seek, SEEK_SET) != seek)
		return sys_errmsg("cannot seek mtd%d to offset %llu",
				  mtd->dev_num, (unsigned long long)seek);

	ret = write(fd, buf, len);
	if (ret != len)
		return sys_errmsg("cannot write %d bytes to mtd%d (eraseblock %d, offset %d)",
				  len, mtd->dev_num, eb, offs);

	return 0;
}