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/*

 * $Id: mtdcore.c,v 1.1.1.1 2004-04-15 01:51:42 phoenix Exp $

 *

 * Core registration and callback routines for MTD

 * drivers and users.

 *

 */

#include <linux/config.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/ptrace.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/timer.h>

#include <linux/major.h>

#include <linux/fs.h>

#include <linux/ioctl.h>

#include <linux/mtd/compatmac.h>

#ifdef CONFIG_PROC_FS

#include <linux/proc_fs.h>

#endif

#include <linux/mtd/mtd.h>

static DECLARE_MUTEX(mtd_table_mutex);

static struct mtd_info *mtd_table[MAX_MTD_DEVICES];

static struct mtd_notifier *mtd_notifiers = NULL;

/**

 *      add_mtd_device - register an MTD device

 *      @mtd: pointer to new MTD device info structure

 *

 *      Add a device to the list of MTD devices present in the system, and

 *      notify each currently active MTD 'user' of its arrival. Returns

 *      zero on success or 1 on failure, which currently will only happen

 *      if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)

 */

int add_mtd_device(struct mtd_info *mtd)

{

        int i;

        down(&mtd_table_mutex);

        for (i=0; i< MAX_MTD_DEVICES; i++)

                if (!mtd_table[i])

                {

                        struct mtd_notifier *not=mtd_notifiers;

                        mtd_table[i] = mtd;

                        mtd->index = i;

                        DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);

                        while (not)

                        {

                                (*(not->add))(mtd);

                                not = not->next;

                        }

                        up(&mtd_table_mutex);

                        MOD_INC_USE_COUNT;

                        return 0;

                }

        up(&mtd_table_mutex);

        return 1;

}

/**

 *      del_mtd_device - unregister an MTD device

 *      @mtd: pointer to MTD device info structure

 *

 *      Remove a device from the list of MTD devices present in the system,

 *      and notify each currently active MTD 'user' of its departure.

 *      Returns zero on success or 1 on failure, which currently will happen

 *      if the requested device does not appear to be present in the list.

 */

int del_mtd_device (struct mtd_info *mtd)

{

        struct mtd_notifier *not=mtd_notifiers;

        int i;

        down(&mtd_table_mutex);

        for (i=0; i < MAX_MTD_DEVICES; i++)

        {

                if (mtd_table[i] == mtd)

                {

                        while (not)

                        {

                                (*(not->remove))(mtd);

                                not = not->next;

                        }

                        mtd_table[i] = NULL;

                        up (&mtd_table_mutex);

                        MOD_DEC_USE_COUNT;

                        return 0;

                }

        }

        up(&mtd_table_mutex);

        return 1;

}

/**

 *      register_mtd_user - register a 'user' of MTD devices.

 *      @new: pointer to notifier info structure

 *

 *      Registers a pair of callbacks function to be called upon addition

 *      or removal of MTD devices. Causes the 'add' callback to be immediately

 *      invoked for each MTD device currently present in the system.

 */

void register_mtd_user (struct mtd_notifier *new)

{

        int i;

        down(&mtd_table_mutex);

        new->next = mtd_notifiers;

        mtd_notifiers = new;

        MOD_INC_USE_COUNT;

        for (i=0; i< MAX_MTD_DEVICES; i++)

                if (mtd_table[i])

                        new->add(mtd_table[i]);

        up(&mtd_table_mutex);

}

/**

 *      register_mtd_user - unregister a 'user' of MTD devices.

 *      @new: pointer to notifier info structure

 *

 *      Removes a callback function pair from the list of 'users' to be

 *      notified upon addition or removal of MTD devices. Causes the

 *      'remove' callback to be immediately invoked for each MTD device

 *      currently present in the system.

 */

int unregister_mtd_user (struct mtd_notifier *old)

{

        struct mtd_notifier **prev = &mtd_notifiers;

        struct mtd_notifier *cur;

        int i;

        down(&mtd_table_mutex);

        while ((cur = *prev)) {

                if (cur == old) {

                        *prev = cur->next;

                        MOD_DEC_USE_COUNT;

                        for (i=0; i< MAX_MTD_DEVICES; i++)

                                if (mtd_table[i])

                                        old->remove(mtd_table[i]);

                        up(&mtd_table_mutex);

                        return 0;

                }

                prev = &cur->next;

        }

        up(&mtd_table_mutex);

        return 1;

}

/**

 *      __get_mtd_device - obtain a validated handle for an MTD device

 *      @mtd: last known address of the required MTD device

 *      @num: internal device number of the required MTD device

 *

 *      Given a number and NULL address, return the num'th entry in the device

 *      table, if any.  Given an address and num == -1, search the device table

 *      for a device with that address and return if it's still present. Given

 *      both, return the num'th driver only if its address matches. Return NULL

 *      if not. get_mtd_device() increases the use count, but

 *      __get_mtd_device() doesn't - you should generally use get_mtd_device().

 */

struct mtd_info *__get_mtd_device(struct mtd_info *mtd, int num)

{

        struct mtd_info *ret = NULL;

        int i;

        down(&mtd_table_mutex);

        if (num == -1) {

                for (i=0; i< MAX_MTD_DEVICES; i++)

                        if (mtd_table[i] == mtd)

                                ret = mtd_table[i];

        } else if (num < MAX_MTD_DEVICES) {

                ret = mtd_table[num];

                if (mtd && mtd != ret)

                        ret = NULL;

        }

        up(&mtd_table_mutex);

        return ret;

}

/* default_mtd_writev - default mtd writev method for MTD devices that

 *                      dont implement their own

 */

int default_mtd_writev(struct mtd_info *mtd, const struct iovec *vecs,

                       unsigned long count, loff_t to, size_t *retlen)

{

        unsigned long i;

        size_t totlen = 0, thislen;

        int ret = 0;

        if(!mtd->write) {

                ret = -EROFS;

        } else {

                for (i=0; i<count; i++) {

                        if (!vecs[i].iov_len)

                                continue;

                        ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);

                        totlen += thislen;

                        if (ret || thislen != vecs[i].iov_len)

                                break;

                        to += vecs[i].iov_len;

                }

        }

        if (retlen)

                *retlen = totlen;

        return ret;

}

/* default_mtd_readv - default mtd readv method for MTD devices that dont

 *                     implement their own

 */

int default_mtd_readv(struct mtd_info *mtd, struct iovec *vecs,

                      unsigned long count, loff_t from, size_t *retlen)

{

        unsigned long i;

        size_t totlen = 0, thislen;

        int ret = 0;

        if(!mtd->read) {

                ret = -EIO;

        } else {

                for (i=0; i<count; i++) {

                        if (!vecs[i].iov_len)

                                continue;

                        ret = mtd->read(mtd, from, vecs[i].iov_len, &thislen, vecs[i].iov_base);

                        totlen += thislen;

                        if (ret || thislen != vecs[i].iov_len)

                                break;

                        from += vecs[i].iov_len;

                }

        }

        if (retlen)

                *retlen = totlen;

        return ret;

}

EXPORT_SYMBOL(add_mtd_device);

EXPORT_SYMBOL(del_mtd_device);

EXPORT_SYMBOL(__get_mtd_device);

EXPORT_SYMBOL(register_mtd_user);

EXPORT_SYMBOL(unregister_mtd_user);

EXPORT_SYMBOL(default_mtd_writev);

EXPORT_SYMBOL(default_mtd_readv);

/*====================================================================*/

/* Power management code */

#ifdef CONFIG_PM

#include <linux/pm.h>

static struct pm_dev *mtd_pm_dev = NULL;

static int mtd_pm_callback(struct pm_dev *dev, pm_request_t rqst, void *data)

{

        int ret = 0, i;

        if (down_trylock(&mtd_table_mutex))

                return -EAGAIN;

        if (rqst == PM_SUSPEND) {

                for (i = 0; ret == 0 && i < MAX_MTD_DEVICES; i++) {

                        if (mtd_table[i] && mtd_table[i]->suspend)

                                ret = mtd_table[i]->suspend(mtd_table[i]);

                }

        } else i = MAX_MTD_DEVICES-1;

        if (rqst == PM_RESUME || ret) {

                for ( ; i >= 0; i--) {

                        if (mtd_table[i] && mtd_table[i]->resume)

                                mtd_table[i]->resume(mtd_table[i]);

                }

        }

        up(&mtd_table_mutex);

        return ret;

}

#endif

/*====================================================================*/

/* Support for /proc/mtd */

#ifdef CONFIG_PROC_FS

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)

static struct proc_dir_entry *proc_mtd;

#endif

static inline int mtd_proc_info (char *buf, int i)

{

        struct mtd_info *this = mtd_table[i];

        if (!this)

                return 0;

        return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,

                       this->erasesize, this->name);

}

static int mtd_read_proc ( char *page, char **start, off_t off,int count

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)

                       ,int *eof, void *data_unused

#else

                        ,int unused

#endif

                        )

{

        int len, l, i;

        off_t   begin = 0;

        down(&mtd_table_mutex);

        len = sprintf(page, "dev:    size   erasesize  name\n");

        for (i=0; i< MAX_MTD_DEVICES; i++) {

                l = mtd_proc_info(page + len, i);

                len += l;

                if (len+begin > off+count)

                        goto done;

                if (len+begin < off) {

                        begin += len;

                        len = 0;

                }

        }

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)

        *eof = 1;

#endif

done:

        up(&mtd_table_mutex);

        if (off >= len+begin)

                return 0;

        *start = page + (off-begin);

        return ((count < begin+len-off) ? count : begin+len-off);

}

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,0)

struct proc_dir_entry mtd_proc_entry = {

        0,                 /* low_ino: the inode -- dynamic */

        3, "mtd",     /* len of name and name */

        S_IFREG | S_IRUGO, /* mode */

        1, 0, 0,           /* nlinks, owner, group */

        0, NULL,           /* size - unused; operations -- use default */

        &mtd_read_proc,   /* function used to read data */

        /* nothing more */

    };

#endif

#endif /* CONFIG_PROC_FS */

/*====================================================================*/

/* Init code */

int __init init_mtd(void)

{

#ifdef CONFIG_PROC_FS

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)

        if ((proc_mtd = create_proc_entry( "mtd", 0, 0 )))

          proc_mtd->read_proc = mtd_read_proc;

#else

        proc_register_dynamic(&proc_root,&mtd_proc_entry);

#endif

#endif

#if LINUX_VERSION_CODE < 0x20212

        init_mtd_devices();

#endif

#ifdef CONFIG_PM

        mtd_pm_dev = pm_register(PM_UNKNOWN_DEV, 0, mtd_pm_callback);

#endif

        return 0;

}

static void __exit cleanup_mtd(void)

{

#ifdef CONFIG_PM

        if (mtd_pm_dev) {

                pm_unregister(mtd_pm_dev);

                mtd_pm_dev = NULL;

        }

#endif

#ifdef CONFIG_PROC_FS

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)

        if (proc_mtd)

          remove_proc_entry( "mtd", 0);

#else

        proc_unregister(&proc_root,mtd_proc_entry.low_ino);

#endif

#endif

}

module_init(init_mtd);

module_exit(cleanup_mtd);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");

MODULE_DESCRIPTION("Core MTD registration and access routines");