145 lines
3.4 KiB
C
145 lines
3.4 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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/compat.h>
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#include <ubi_uboot.h>
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struct mtd_info *mtd_table[MAX_MTD_DEVICES];
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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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for (i = 0; i < MAX_MTD_DEVICES; i++)
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if (!mtd_table[i]) {
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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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/* 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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/* 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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return 0;
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}
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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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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)"
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" 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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/* 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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mtd_table[mtd->index] = NULL;
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ret = 0;
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}
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return ret;
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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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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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ret->usecount++;
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return ret;
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out_unlock:
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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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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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mtd->usecount++;
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return mtd;
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out_unlock:
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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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c = --mtd->usecount;
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BUG_ON(c < 0);
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}
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