![David Woodhouse](/assets/img/avatar_default.png)
While we're fixing up the newly-added symbol, change the neighbouring ones too, for consistency and also to reflect the author's interpretation of the GPL -- which is that _no_ non-GPL modules are permitted. The author always intended his code to be released under the GPL, and believes that any new interpretation of 'EXPORT_SYMBOL' as being any different from 'EXPORT_SYMBOL_GPL' is entirely invalid; the GPL requires that _all_ exports have the semantics of the new 'EXPORT_SYMBOL_GPL', which means the extra four characters are entirely redundant. But since those four extra characters trigger the check for illegal modules in a way that just EXPORT_SYMBOL does not, it's useful to change anyway. This action in no way indicates an admission that there is any legal distinction between the two states, and in particular does not indicate that the author believes that non-GPL modules may use symbols exported with EXPORT_SYMBOL alone. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
412 lines
9.5 KiB
C
412 lines
9.5 KiB
C
/*
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* $Id: mtdcore.c,v 1.47 2005/11/07 11:14:20 gleixner Exp $
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*
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* Core registration and callback routines for MTD
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* drivers and users.
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/timer.h>
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#include <linux/major.h>
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#include <linux/fs.h>
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#include <linux/err.h>
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#include <linux/ioctl.h>
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#include <linux/init.h>
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#include <linux/mtd/compatmac.h>
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#include <linux/proc_fs.h>
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#include <linux/mtd/mtd.h>
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/* These are exported solely for the purpose of mtd_blkdevs.c. You
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should not use them for _anything_ else */
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DEFINE_MUTEX(mtd_table_mutex);
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struct mtd_info *mtd_table[MAX_MTD_DEVICES];
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EXPORT_SYMBOL_GPL(mtd_table_mutex);
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EXPORT_SYMBOL_GPL(mtd_table);
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static LIST_HEAD(mtd_notifiers);
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/**
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* add_mtd_device - register an MTD device
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* @mtd: pointer to new MTD device info structure
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*
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* Add a device to the list of MTD devices present in the system, and
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* notify each currently active MTD 'user' of its arrival. Returns
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* zero on success or 1 on failure, which currently will only happen
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* if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
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*/
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int add_mtd_device(struct mtd_info *mtd)
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{
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int i;
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BUG_ON(mtd->writesize == 0);
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mutex_lock(&mtd_table_mutex);
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for (i=0; i < MAX_MTD_DEVICES; i++)
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if (!mtd_table[i]) {
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struct list_head *this;
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mtd_table[i] = mtd;
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mtd->index = i;
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mtd->usecount = 0;
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/* Some chips always power up locked. Unlock them now */
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if ((mtd->flags & MTD_WRITEABLE)
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&& (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {
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if (mtd->unlock(mtd, 0, mtd->size))
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printk(KERN_WARNING
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"%s: unlock failed, "
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"writes may not work\n",
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mtd->name);
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}
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DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
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/* No need to get a refcount on the module containing
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the notifier, since we hold the mtd_table_mutex */
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list_for_each(this, &mtd_notifiers) {
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struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
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not->add(mtd);
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}
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mutex_unlock(&mtd_table_mutex);
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/* We _know_ we aren't being removed, because
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our caller is still holding us here. So none
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of this try_ nonsense, and no bitching about it
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either. :) */
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__module_get(THIS_MODULE);
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return 0;
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}
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mutex_unlock(&mtd_table_mutex);
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return 1;
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}
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/**
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* del_mtd_device - unregister an MTD device
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* @mtd: pointer to MTD device info structure
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*
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* Remove a device from the list of MTD devices present in the system,
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* and notify each currently active MTD 'user' of its departure.
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* Returns zero on success or 1 on failure, which currently will happen
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* if the requested device does not appear to be present in the list.
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*/
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int del_mtd_device (struct mtd_info *mtd)
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{
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int ret;
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mutex_lock(&mtd_table_mutex);
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if (mtd_table[mtd->index] != mtd) {
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ret = -ENODEV;
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} else if (mtd->usecount) {
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printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
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mtd->index, mtd->name, mtd->usecount);
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ret = -EBUSY;
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} else {
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struct list_head *this;
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/* No need to get a refcount on the module containing
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the notifier, since we hold the mtd_table_mutex */
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list_for_each(this, &mtd_notifiers) {
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struct mtd_notifier *not = list_entry(this, struct mtd_notifier, list);
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not->remove(mtd);
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}
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mtd_table[mtd->index] = NULL;
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module_put(THIS_MODULE);
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ret = 0;
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}
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mutex_unlock(&mtd_table_mutex);
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return ret;
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}
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/**
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* register_mtd_user - register a 'user' of MTD devices.
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* @new: pointer to notifier info structure
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*
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* Registers a pair of callbacks function to be called upon addition
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* or removal of MTD devices. Causes the 'add' callback to be immediately
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* invoked for each MTD device currently present in the system.
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*/
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void register_mtd_user (struct mtd_notifier *new)
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{
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int i;
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mutex_lock(&mtd_table_mutex);
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list_add(&new->list, &mtd_notifiers);
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__module_get(THIS_MODULE);
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for (i=0; i< MAX_MTD_DEVICES; i++)
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if (mtd_table[i])
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new->add(mtd_table[i]);
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mutex_unlock(&mtd_table_mutex);
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}
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/**
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* unregister_mtd_user - unregister a 'user' of MTD devices.
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* @old: pointer to notifier info structure
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*
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* Removes a callback function pair from the list of 'users' to be
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* notified upon addition or removal of MTD devices. Causes the
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* 'remove' callback to be immediately invoked for each MTD device
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* currently present in the system.
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*/
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int unregister_mtd_user (struct mtd_notifier *old)
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{
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int i;
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mutex_lock(&mtd_table_mutex);
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module_put(THIS_MODULE);
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for (i=0; i< MAX_MTD_DEVICES; i++)
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if (mtd_table[i])
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old->remove(mtd_table[i]);
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list_del(&old->list);
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mutex_unlock(&mtd_table_mutex);
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return 0;
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}
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/**
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* get_mtd_device - obtain a validated handle for an MTD device
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* @mtd: last known address of the required MTD device
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* @num: internal device number of the required MTD device
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*
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* Given a number and NULL address, return the num'th entry in the device
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* table, if any. Given an address and num == -1, search the device table
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* for a device with that address and return if it's still present. Given
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* both, return the num'th driver only if its address matches. Return
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* error code if not.
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*/
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struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
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{
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struct mtd_info *ret = NULL;
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int i, err = -ENODEV;
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mutex_lock(&mtd_table_mutex);
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if (num == -1) {
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for (i=0; i< MAX_MTD_DEVICES; i++)
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if (mtd_table[i] == mtd)
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ret = mtd_table[i];
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} else if (num < MAX_MTD_DEVICES) {
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ret = mtd_table[num];
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if (mtd && mtd != ret)
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ret = NULL;
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}
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if (!ret)
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goto out_unlock;
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if (!try_module_get(ret->owner))
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goto out_unlock;
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if (ret->get_device) {
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err = ret->get_device(ret);
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if (err)
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goto out_put;
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}
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ret->usecount++;
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mutex_unlock(&mtd_table_mutex);
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return ret;
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out_put:
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module_put(ret->owner);
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out_unlock:
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mutex_unlock(&mtd_table_mutex);
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return ERR_PTR(err);
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}
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/**
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* get_mtd_device_nm - obtain a validated handle for an MTD device by
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* device name
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* @name: MTD device name to open
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*
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* This function returns MTD device description structure in case of
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* success and an error code in case of failure.
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*/
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struct mtd_info *get_mtd_device_nm(const char *name)
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{
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int i, err = -ENODEV;
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struct mtd_info *mtd = NULL;
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mutex_lock(&mtd_table_mutex);
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for (i = 0; i < MAX_MTD_DEVICES; i++) {
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if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
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mtd = mtd_table[i];
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break;
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}
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}
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if (!mtd)
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goto out_unlock;
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if (!try_module_get(mtd->owner))
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goto out_unlock;
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if (mtd->get_device) {
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err = mtd->get_device(mtd);
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if (err)
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goto out_put;
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}
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mtd->usecount++;
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mutex_unlock(&mtd_table_mutex);
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return mtd;
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out_put:
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module_put(mtd->owner);
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out_unlock:
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mutex_unlock(&mtd_table_mutex);
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return ERR_PTR(err);
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}
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void put_mtd_device(struct mtd_info *mtd)
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{
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int c;
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mutex_lock(&mtd_table_mutex);
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c = --mtd->usecount;
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if (mtd->put_device)
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mtd->put_device(mtd);
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mutex_unlock(&mtd_table_mutex);
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BUG_ON(c < 0);
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module_put(mtd->owner);
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}
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/* default_mtd_writev - default mtd writev method for MTD devices that
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* don't implement their own
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*/
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int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
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unsigned long count, loff_t to, size_t *retlen)
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{
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unsigned long i;
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size_t totlen = 0, thislen;
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int ret = 0;
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if(!mtd->write) {
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ret = -EROFS;
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} else {
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for (i=0; i<count; i++) {
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if (!vecs[i].iov_len)
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continue;
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ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
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totlen += thislen;
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if (ret || thislen != vecs[i].iov_len)
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break;
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to += vecs[i].iov_len;
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}
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}
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if (retlen)
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*retlen = totlen;
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return ret;
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}
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EXPORT_SYMBOL_GPL(add_mtd_device);
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EXPORT_SYMBOL_GPL(del_mtd_device);
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EXPORT_SYMBOL_GPL(get_mtd_device);
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EXPORT_SYMBOL_GPL(get_mtd_device_nm);
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EXPORT_SYMBOL_GPL(put_mtd_device);
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EXPORT_SYMBOL_GPL(register_mtd_user);
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EXPORT_SYMBOL_GPL(unregister_mtd_user);
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EXPORT_SYMBOL_GPL(default_mtd_writev);
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#ifdef CONFIG_PROC_FS
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/*====================================================================*/
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/* Support for /proc/mtd */
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static struct proc_dir_entry *proc_mtd;
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static inline int mtd_proc_info (char *buf, int i)
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{
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struct mtd_info *this = mtd_table[i];
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if (!this)
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return 0;
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return sprintf(buf, "mtd%d: %8.8x %8.8x \"%s\"\n", i, this->size,
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this->erasesize, this->name);
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}
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static int mtd_read_proc (char *page, char **start, off_t off, int count,
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int *eof, void *data_unused)
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{
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int len, l, i;
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off_t begin = 0;
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mutex_lock(&mtd_table_mutex);
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len = sprintf(page, "dev: size erasesize name\n");
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for (i=0; i< MAX_MTD_DEVICES; i++) {
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l = mtd_proc_info(page + len, i);
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len += l;
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if (len+begin > off+count)
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goto done;
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if (len+begin < off) {
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begin += len;
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len = 0;
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}
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}
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*eof = 1;
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done:
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mutex_unlock(&mtd_table_mutex);
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if (off >= len+begin)
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return 0;
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*start = page + (off-begin);
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return ((count < begin+len-off) ? count : begin+len-off);
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}
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/*====================================================================*/
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/* Init code */
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static int __init init_mtd(void)
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{
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if ((proc_mtd = create_proc_entry( "mtd", 0, NULL )))
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proc_mtd->read_proc = mtd_read_proc;
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return 0;
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}
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static void __exit cleanup_mtd(void)
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{
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if (proc_mtd)
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remove_proc_entry( "mtd", NULL);
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}
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module_init(init_mtd);
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module_exit(cleanup_mtd);
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#endif /* CONFIG_PROC_FS */
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
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MODULE_DESCRIPTION("Core MTD registration and access routines");
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