/* * $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/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/init.h> #include <linux/mtd/compatmac.h> #include <linux/proc_fs.h> #include <linux/mtd/mtd.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; 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 NULL * if not. */ struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num) { struct mtd_info *ret = NULL; int i; 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 && !try_module_get(ret->owner)) ret = NULL; if (ret) ret->usecount++; mutex_unlock(&mtd_table_mutex); return ret; } void put_mtd_device(struct mtd_info *mtd) { int c; mutex_lock(&mtd_table_mutex); c = --mtd->usecount; mutex_unlock(&mtd_table_mutex); BUG_ON(c < 0); module_put(mtd->owner); } /* 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 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(add_mtd_device); EXPORT_SYMBOL(del_mtd_device); EXPORT_SYMBOL(get_mtd_device); EXPORT_SYMBOL(put_mtd_device); EXPORT_SYMBOL(register_mtd_user); EXPORT_SYMBOL(unregister_mtd_user); EXPORT_SYMBOL(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");