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/*

 * $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $

 *

 * Core registration and callback routines for MTD

 * drivers and users.

 *

 */

#include <linux/module.h>

#include <linux/kernel.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/err.h>

#include <linux/ioctl.h>

#include <linux/init.h>

#include <linux/mtd/compatmac.h>

#include <linux/proc_fs.h>

#include <linux/mtd/mtd.h>

#include "mtdcore.h"

/* These are exported solely for the purpose of mtd_blkdevs.c. You

   should not use them for _anything_ else */

DEFINE_MUTEX(mtd_table_mutex);

struct mtd_info *mtd_table[MAX_MTD_DEVICES];

EXPORT_SYMBOL_GPL(mtd_table_mutex);

EXPORT_SYMBOL_GPL(mtd_table);

static LIST_HEAD(mtd_notifiers);

/**

 *      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;

        BUG_ON(mtd->writesize == 0);

        mutex_lock(&mtd_table_mutex);

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

                if (!mtd_table[i]) {

                        struct list_head *this;

                        mtd_table[i] = mtd;

                        mtd->index = i;

                        mtd->usecount = 0;

                        /* Some chips always power up locked. Unlock them now */

                        if ((mtd->flags & MTD_WRITEABLE)

                            && (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {

                                if (mtd->unlock(mtd, 0, mtd->size))

                                        printk(KERN_WARNING

                                               "%s: unlock failed, "

                                               "writes may not work\n",

                                               mtd->name);

                        }

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

                        /* No need to get a refcount on the module containing

                           the notifier, since we hold the mtd_table_mutex */

                        list_for_each(this, &mtd_notifiers) {

                                struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);

                                not->add(mtd);

                        }

                        mutex_unlock(&mtd_table_mutex);

                        /* We _know_ we aren't being removed, because

                           our caller is still holding us here. So none

                           of this try_ nonsense, and no bitching about it

                           either. :) */

                        __module_get(THIS_MODULE);

                        return 0;

                }

        mutex_unlock(&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)

{

        int ret;

        mutex_lock(&mtd_table_mutex);

        if (mtd_table[mtd->index] != mtd) {

                ret = -ENODEV;

        } else if (mtd->usecount) {

                printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",

                       mtd->index, mtd->name, mtd->usecount);

                ret = -EBUSY;

        } else {

                struct list_head *this;

                /* No need to get a refcount on the module containing

                   the notifier, since we hold the mtd_table_mutex */

                list_for_each(this, &mtd_notifiers) {

                        struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);

                        not->remove(mtd);

                }

                mtd_table[mtd->index] = NULL;

                module_put(THIS_MODULE);

                ret = 0;

        }

        mutex_unlock(&mtd_table_mutex);

        return ret;

}

/**

 *      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;

        mutex_lock(&mtd_table_mutex);

        list_add(&new->list, &mtd_notifiers);

        __module_get(THIS_MODULE);

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

                if (mtd_table[i])

                        new->add(mtd_table[i]);

        mutex_unlock(&mtd_table_mutex);

}

/**

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

 *      @old: 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)

{

        int i;

        mutex_lock(&mtd_table_mutex);

        module_put(THIS_MODULE);

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

                if (mtd_table[i])

                        old->remove(mtd_table[i]);

        list_del(&old->list);

        mutex_unlock(&mtd_table_mutex);

        return 0;

}

/**

 *      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

 *      error code if not.

 */

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

{

        struct mtd_info *ret = NULL;

        int i, err = -ENODEV;

        mutex_lock(&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;

        }

        if (!ret)

                goto out_unlock;

        if (!try_module_get(ret->owner))

                goto out_unlock;

        if (ret->get_device) {

                err = ret->get_device(ret);

                if (err)

                        goto out_put;

        }

        ret->usecount++;

        mutex_unlock(&mtd_table_mutex);

        return ret;

out_put:

        module_put(ret->owner);

out_unlock:

        mutex_unlock(&mtd_table_mutex);

        return ERR_PTR(err);

}

/**

 *      get_mtd_device_nm - obtain a validated handle for an MTD device by

 *      device name

 *      @name: MTD device name to open

 *

 *      This function returns MTD device description structure in case of

 *      success and an error code in case of failure.

 */

struct mtd_info *get_mtd_device_nm(const char *name)

{

        int i, err = -ENODEV;

        struct mtd_info *mtd = NULL;

        mutex_lock(&mtd_table_mutex);

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

                if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {

                        mtd = mtd_table[i];

                        break;

                }

        }

        if (!mtd)

                goto out_unlock;

        if (!try_module_get(mtd->owner))

                goto out_unlock;

        if (mtd->get_device) {

                err = mtd->get_device(mtd);

                if (err)

                        goto out_put;

        }

        mtd->usecount++;

        mutex_unlock(&mtd_table_mutex);

        return mtd;

out_put:

        module_put(mtd->owner);

out_unlock:

        mutex_unlock(&mtd_table_mutex);

        return ERR_PTR(err);

}

void put_mtd_device(struct mtd_info *mtd)

{

        int c;

        mutex_lock(&mtd_table_mutex);

        c = --mtd->usecount;

        if (mtd->put_device)

                mtd->put_device(mtd);

        mutex_unlock(&mtd_table_mutex);

        BUG_ON(c < 0);

        module_put(mtd->owner);

}

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

 *                      don't implement their own

 */

int default_mtd_writev(struct mtd_info *mtd, const struct kvec *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;

}

EXPORT_SYMBOL_GPL(add_mtd_device);

EXPORT_SYMBOL_GPL(del_mtd_device);

EXPORT_SYMBOL_GPL(get_mtd_device);

EXPORT_SYMBOL_GPL(get_mtd_device_nm);

EXPORT_SYMBOL_GPL(put_mtd_device);

EXPORT_SYMBOL_GPL(register_mtd_user);

EXPORT_SYMBOL_GPL(unregister_mtd_user);

EXPORT_SYMBOL_GPL(default_mtd_writev);

#ifdef CONFIG_PROC_FS

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

/* Support for /proc/mtd */

static struct proc_dir_entry *proc_mtd;

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,

                          int *eof, void *data_unused)

{

        int len, l, i;

        off_t   begin = 0;

        mutex_lock(&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;

                }

        }

        *eof = 1;

done:

        mutex_unlock(&mtd_table_mutex);

        if (off >= len+begin)

                return 0;

        *start = page + (off-begin);

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

}

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

/* Init code */

static int __init init_mtd(void)

{

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

                proc_mtd->read_proc = mtd_read_proc;

        return 0;

}

static void __exit cleanup_mtd(void)

{

        if (proc_mtd)

                remove_proc_entry( "mtd", NULL);

}

module_init(init_mtd);

module_exit(cleanup_mtd);

#endif /* CONFIG_PROC_FS */

MODULE_LICENSE("GPL");

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

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