402d326519
Present backing device capabilities for MTD character device files to allow NOMMU mmap to do direct mapping where possible. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Bernd Schmidt <bernd.schmidt@analog.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
436 lines
10 KiB
C
436 lines
10 KiB
C
/*
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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/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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#include "internal.h"
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#include "mtdcore.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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if (!mtd->backing_dev_info) {
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switch (mtd->type) {
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case MTD_RAM:
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mtd->backing_dev_info = &mtd_bdi_rw_mappable;
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break;
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case MTD_ROM:
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mtd->backing_dev_info = &mtd_bdi_ro_mappable;
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break;
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default:
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mtd->backing_dev_info = &mtd_bdi_unmappable;
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break;
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}
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}
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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 mtd_notifier *not;
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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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if (is_power_of_2(mtd->erasesize))
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mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
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else
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mtd->erasesize_shift = 0;
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if (is_power_of_2(mtd->writesize))
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mtd->writesize_shift = ffs(mtd->writesize) - 1;
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else
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mtd->writesize_shift = 0;
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mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
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mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
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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_POWERUP_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_entry(not, &mtd_notifiers, list)
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not->add(mtd);
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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 mtd_notifier *not;
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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_entry(not, &mtd_notifiers, list)
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not->remove(mtd);
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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: %8.8llx %8.8x \"%s\"\n", i,
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(unsigned long long)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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