1 files changed, 478 insertions, 0 deletions

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
new file mode 100644
index 000000000000..f8d2185819e7
--- /dev/null
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -0,0 +1,478 @@
+/*
+ * $Id: mtd_blkdevs.c,v 1.24 2004/11/16 18:28:59 dwmw2 Exp $
+ *
+ * (C) 2003 David Woodhouse <dwmw2@infradead.org>
+ *
+ * Interface to Linux 2.5 block layer for MTD 'translation layers'.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/mtd/blktrans.h>
+#include <linux/mtd/mtd.h>
+#include <linux/blkdev.h>
+#include <linux/blkpg.h>
+#include <linux/spinlock.h>
+#include <linux/hdreg.h>
+#include <linux/init.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+#include <linux/devfs_fs_kernel.h>
+
+static LIST_HEAD(blktrans_majors);
+
+extern struct semaphore mtd_table_mutex;
+extern struct mtd_info *mtd_table[];
+
+struct mtd_blkcore_priv {
+	struct completion thread_dead;
+	int exiting;
+	wait_queue_head_t thread_wq;
+	struct request_queue *rq;
+	spinlock_t queue_lock;
+};
+
+static int do_blktrans_request(struct mtd_blktrans_ops *tr,
+			       struct mtd_blktrans_dev *dev,
+			       struct request *req)
+{
+	unsigned long block, nsect;
+	char *buf;
+
+	block = req->sector;
+	nsect = req->current_nr_sectors;
+	buf = req->buffer;
+
+	if (!(req->flags & REQ_CMD))
+		return 0;
+
+	if (block + nsect > get_capacity(req->rq_disk))
+		return 0;
+
+	switch(rq_data_dir(req)) {
+	case READ:
+		for (; nsect > 0; nsect--, block++, buf += 512)
+			if (tr->readsect(dev, block, buf))
+				return 0;
+		return 1;
+
+	case WRITE:
+		if (!tr->writesect)
+			return 0;
+
+		for (; nsect > 0; nsect--, block++, buf += 512)
+			if (tr->writesect(dev, block, buf))
+				return 0;
+		return 1;
+
+	default:
+		printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req));
+		return 0;
+	}
+}
+
+static int mtd_blktrans_thread(void *arg)
+{
+	struct mtd_blktrans_ops *tr = arg;
+	struct request_queue *rq = tr->blkcore_priv->rq;
+
+	/* we might get involved when memory gets low, so use PF_MEMALLOC */
+	current->flags |= PF_MEMALLOC | PF_NOFREEZE;
+
+	daemonize("%sd", tr->name);
+
+	/* daemonize() doesn't do this for us since some kernel threads
+	   actually want to deal with signals. We can't just call 
+	   exit_sighand() since that'll cause an oops when we finally
+	   do exit. */
+	spin_lock_irq(&current->sighand->siglock);
+	sigfillset(&current->blocked);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	spin_lock_irq(rq->queue_lock);
+		
+	while (!tr->blkcore_priv->exiting) {
+		struct request *req;
+		struct mtd_blktrans_dev *dev;
+		int res = 0;
+		DECLARE_WAITQUEUE(wait, current);
+
+		req = elv_next_request(rq);
+
+		if (!req) {
+			add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
+			set_current_state(TASK_INTERRUPTIBLE);
+
+			spin_unlock_irq(rq->queue_lock);
+
+			schedule();
+			remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
+
+			spin_lock_irq(rq->queue_lock);
+
+			continue;
+		}
+
+		dev = req->rq_disk->private_data;
+		tr = dev->tr;
+
+		spin_unlock_irq(rq->queue_lock);
+
+		down(&dev->sem);
+		res = do_blktrans_request(tr, dev, req);
+		up(&dev->sem);
+
+		spin_lock_irq(rq->queue_lock);
+
+		end_request(req, res);
+	}
+	spin_unlock_irq(rq->queue_lock);
+
+	complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
+}
+
+static void mtd_blktrans_request(struct request_queue *rq)
+{
+	struct mtd_blktrans_ops *tr = rq->queuedata;
+	wake_up(&tr->blkcore_priv->thread_wq);
+}
+
+
+static int blktrans_open(struct inode *i, struct file *f)
+{
+	struct mtd_blktrans_dev *dev;
+	struct mtd_blktrans_ops *tr;
+	int ret = -ENODEV;
+
+	dev = i->i_bdev->bd_disk->private_data;
+	tr = dev->tr;
+
+	if (!try_module_get(dev->mtd->owner))
+		goto out;
+
+	if (!try_module_get(tr->owner))
+		goto out_tr;
+
+	/* FIXME: Locking. A hot pluggable device can go away 
+	   (del_mtd_device can be called for it) without its module
+	   being unloaded. */
+	dev->mtd->usecount++;
+
+	ret = 0;
+	if (tr->open && (ret = tr->open(dev))) {
+		dev->mtd->usecount--;
+		module_put(dev->mtd->owner);
+	out_tr:
+		module_put(tr->owner);
+	}
+ out:
+	return ret;
+}
+
+static int blktrans_release(struct inode *i, struct file *f)
+{
+	struct mtd_blktrans_dev *dev;
+	struct mtd_blktrans_ops *tr;
+	int ret = 0;
+
+	dev = i->i_bdev->bd_disk->private_data;
+	tr = dev->tr;
+
+	if (tr->release)
+		ret = tr->release(dev);
+
+	if (!ret) {
+		dev->mtd->usecount--;
+		module_put(dev->mtd->owner);
+		module_put(tr->owner);
+	}
+
+	return ret;
+}
+
+
+static int blktrans_ioctl(struct inode *inode, struct file *file, 
+			      unsigned int cmd, unsigned long arg)
+{
+	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
+	struct mtd_blktrans_ops *tr = dev->tr;
+
+	switch (cmd) {
+	case BLKFLSBUF:
+		if (tr->flush)
+			return tr->flush(dev);
+		/* The core code did the work, we had nothing to do. */
+		return 0;
+
+	case HDIO_GETGEO:
+		if (tr->getgeo) {
+			struct hd_geometry g;
+			int ret;
+
+			memset(&g, 0, sizeof(g));
+			ret = tr->getgeo(dev, &g);
+			if (ret)
+				return ret;
+
+			g.start = get_start_sect(inode->i_bdev);
+			if (copy_to_user((void __user *)arg, &g, sizeof(g)))
+				return -EFAULT;
+			return 0;
+		} /* else */
+	default:
+		return -ENOTTY;
+	}
+}
+
+struct block_device_operations mtd_blktrans_ops = {
+	.owner		= THIS_MODULE,
+	.open		= blktrans_open,
+	.release	= blktrans_release,
+	.ioctl		= blktrans_ioctl,
+};
+
+int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
+{
+	struct mtd_blktrans_ops *tr = new->tr;
+	struct list_head *this;
+	int last_devnum = -1;
+	struct gendisk *gd;
+
+	if (!down_trylock(&mtd_table_mutex)) {
+		up(&mtd_table_mutex);
+		BUG();
+	}
+
+	list_for_each(this, &tr->devs) {
+		struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
+		if (new->devnum == -1) {
+			/* Use first free number */
+			if (d->devnum != last_devnum+1) {
+				/* Found a free devnum. Plug it in here */
+				new->devnum = last_devnum+1;
+				list_add_tail(&new->list, &d->list);
+				goto added;
+			}
+		} else if (d->devnum == new->devnum) {
+			/* Required number taken */
+			return -EBUSY;
+		} else if (d->devnum > new->devnum) {
+			/* Required number was free */
+			list_add_tail(&new->list, &d->list);
+			goto added;
+		} 
+		last_devnum = d->devnum;
+	}
+	if (new->devnum == -1)
+		new->devnum = last_devnum+1;
+
+	if ((new->devnum << tr->part_bits) > 256) {
+		return -EBUSY;
+	}
+
+	init_MUTEX(&new->sem);
+	list_add_tail(&new->list, &tr->devs);
+ added:
+	if (!tr->writesect)
+		new->readonly = 1;
+
+	gd = alloc_disk(1 << tr->part_bits);
+	if (!gd) {
+		list_del(&new->list);
+		return -ENOMEM;
+	}
+	gd->major = tr->major;
+	gd->first_minor = (new->devnum) << tr->part_bits;
+	gd->fops = &mtd_blktrans_ops;
+	
+	snprintf(gd->disk_name, sizeof(gd->disk_name),
+		 "%s%c", tr->name, (tr->part_bits?'a':'0') + new->devnum);
+	snprintf(gd->devfs_name, sizeof(gd->devfs_name),
+		 "%s/%c", tr->name, (tr->part_bits?'a':'0') + new->devnum);
+
+	/* 2.5 has capacity in units of 512 bytes while still
+	   having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
+	set_capacity(gd, (new->size * new->blksize) >> 9);
+
+	gd->private_data = new;
+	new->blkcore_priv = gd;
+	gd->queue = tr->blkcore_priv->rq;
+
+	if (new->readonly)
+		set_disk_ro(gd, 1);
+
+	add_disk(gd);
+	
+	return 0;
+}
+
+int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
+{
+	if (!down_trylock(&mtd_table_mutex)) {
+		up(&mtd_table_mutex);
+		BUG();
+	}
+
+	list_del(&old->list);
+
+	del_gendisk(old->blkcore_priv);
+	put_disk(old->blkcore_priv);
+		
+	return 0;
+}
+
+static void blktrans_notify_remove(struct mtd_info *mtd)
+{
+	struct list_head *this, *this2, *next;
+
+	list_for_each(this, &blktrans_majors) {
+		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
+
+		list_for_each_safe(this2, next, &tr->devs) {
+			struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
+
+			if (dev->mtd == mtd)
+				tr->remove_dev(dev);
+		}
+	}
+}
+
+static void blktrans_notify_add(struct mtd_info *mtd)
+{
+	struct list_head *this;
+
+	if (mtd->type == MTD_ABSENT)
+		return;
+
+	list_for_each(this, &blktrans_majors) {
+		struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
+
+		tr->add_mtd(tr, mtd);
+	}
+
+}
+
+static struct mtd_notifier blktrans_notifier = {
+	.add = blktrans_notify_add,
+	.remove = blktrans_notify_remove,
+};
+      
+int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
+{
+	int ret, i;
+
+	/* Register the notifier if/when the first device type is 
+	   registered, to prevent the link/init ordering from fucking
+	   us over. */
+	if (!blktrans_notifier.list.next)
+		register_mtd_user(&blktrans_notifier);
+
+	tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
+	if (!tr->blkcore_priv)
+		return -ENOMEM;
+
+	memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));
+
+	down(&mtd_table_mutex);
+
+	ret = register_blkdev(tr->major, tr->name);
+	if (ret) {
+		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
+		       tr->name, tr->major, ret);
+		kfree(tr->blkcore_priv);
+		up(&mtd_table_mutex);
+		return ret;
+	}
+	spin_lock_init(&tr->blkcore_priv->queue_lock);
+	init_completion(&tr->blkcore_priv->thread_dead);
+	init_waitqueue_head(&tr->blkcore_priv->thread_wq);
+
+	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
+	if (!tr->blkcore_priv->rq) {
+		unregister_blkdev(tr->major, tr->name);
+		kfree(tr->blkcore_priv);
+		up(&mtd_table_mutex);
+		return -ENOMEM;
+	}
+
+	tr->blkcore_priv->rq->queuedata = tr;
+
+	ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);
+	if (ret < 0) {
+		blk_cleanup_queue(tr->blkcore_priv->rq);
+		unregister_blkdev(tr->major, tr->name);
+		kfree(tr->blkcore_priv);
+		up(&mtd_table_mutex);
+		return ret;
+	} 
+
+	devfs_mk_dir(tr->name);
+
+	INIT_LIST_HEAD(&tr->devs);
+	list_add(&tr->list, &blktrans_majors);
+
+	for (i=0; i<MAX_MTD_DEVICES; i++) {
+		if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
+			tr->add_mtd(tr, mtd_table[i]);
+	}
+
+	up(&mtd_table_mutex);
+
+	return 0;
+}
+
+int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
+{
+	struct list_head *this, *next;
+
+	down(&mtd_table_mutex);
+
+	/* Clean up the kernel thread */
+	tr->blkcore_priv->exiting = 1;
+	wake_up(&tr->blkcore_priv->thread_wq);
+	wait_for_completion(&tr->blkcore_priv->thread_dead);
+
+	/* Remove it from the list of active majors */
+	list_del(&tr->list);
+
+	list_for_each_safe(this, next, &tr->devs) {
+		struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
+		tr->remove_dev(dev);
+	}
+
+	devfs_remove(tr->name);
+	blk_cleanup_queue(tr->blkcore_priv->rq);
+	unregister_blkdev(tr->major, tr->name);
+
+	up(&mtd_table_mutex);
+
+	kfree(tr->blkcore_priv);
+
+	if (!list_empty(&tr->devs))
+		BUG();
+	return 0;
+}
+
+static void __exit mtd_blktrans_exit(void)
+{
+	/* No race here -- if someone's currently in register_mtd_blktrans
+	   we're screwed anyway. */
+	if (blktrans_notifier.list.next)
+		unregister_mtd_user(&blktrans_notifier);
+}
+
+module_exit(mtd_blktrans_exit);
+
+EXPORT_SYMBOL_GPL(register_mtd_blktrans);
+EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
+EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
+EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
+
+MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");