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path: root/drivers/mtd/mtd_blkdevs.c
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Diffstat (limited to 'drivers/mtd/mtd_blkdevs.c')
-rw-r--r--drivers/mtd/mtd_blkdevs.c478
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 00000000000..f8d2185819e
--- /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'");