patch-2.4.19 linux-2.4.19/drivers/mtd/mtdconcat.c

• Lines: 673
• Date: Fri Aug 2 17:39:44 2002
• Orig file: linux-2.4.18/drivers/mtd/mtdconcat.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.18/drivers/mtd/mtdconcat.c linux-2.4.19/drivers/mtd/mtdconcat.c
@@ -0,0 +1,672 @@
+/*
+ * MTD device concatenation layer
+ *
+ * (C) 2002 Robert Kaiser <rkaiser@sysgo.de>
+ *
+ * This code is GPL
+ *
+ * $Id: mtdconcat.c,v 1.2 2002/03/22 08:45:22 dwmw2 Exp $
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/concat.h>
+
+/*
+ * Our storage structure:
+ * Subdev points to an array of pointers to struct mtd_info objects
+ * which is allocated along with this structure
+ *
+ */
+struct mtd_concat {
+	struct mtd_info mtd;
+	int             num_subdev;
+	struct mtd_info **subdev;
+};
+
+/*
+ * how to calculate the size required for the above structure,
+ * including the pointer array subdev points to:
+ */
+#define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)	\
+	((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
+
+
+/*
+ * Given a pointer to the MTD object in the mtd_concat structure,
+ * we can retrieve the pointer to that structure with this macro.
+ */
+#define CONCAT(x)  ((struct mtd_concat *)(x))
+
+	
+/* 
+ * MTD methods which look up the relevant subdevice, translate the
+ * effective address and pass through to the subdevice.
+ */
+
+static int concat_read (struct mtd_info *mtd, loff_t from, size_t len, 
+			size_t *retlen, u_char *buf)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int err = -EINVAL;
+	int i;
+
+	*retlen = 0;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		size_t size, retsize;
+
+		if (from >= subdev->size)
+		{
+			size  = 0;
+			from -= subdev->size;
+		}
+		else
+		{
+			if (from + len > subdev->size)
+				size = subdev->size - from;
+			else
+				size = len;
+
+			err = subdev->read(subdev, from, size, &retsize, buf);
+
+			if(err)
+				break;
+
+			*retlen += retsize;
+			len -= size;
+			if(len == 0)
+				break;
+
+			err = -EINVAL;
+			buf += size;
+			from = 0;
+		}
+	}
+	return err;
+}
+
+static int concat_write (struct mtd_info *mtd, loff_t to, size_t len,
+			size_t *retlen, const u_char *buf)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int err = -EINVAL;
+	int i;
+
+	if (!(mtd->flags & MTD_WRITEABLE))
+		return -EROFS;
+
+	*retlen = 0;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		size_t size, retsize;
+
+		if (to >= subdev->size)
+		{
+			size  = 0;
+			to -= subdev->size;
+		}
+		else
+		{
+			if (to + len > subdev->size)
+				size = subdev->size - to;
+			else
+				size = len;
+
+			if (!(subdev->flags & MTD_WRITEABLE))
+				err = -EROFS;
+			else
+				err = subdev->write(subdev, to, size, &retsize, buf);
+
+			if(err)
+				break;
+
+			*retlen += retsize;
+			len -= size;
+			if(len == 0)
+				break;
+
+			err = -EINVAL;
+			buf += size;
+			to = 0;
+		}
+	}
+	return err;
+}
+
+static void concat_erase_callback (struct erase_info *instr)
+{
+	wake_up((wait_queue_head_t *)instr->priv);
+}
+
+static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
+{
+	int err;
+	wait_queue_head_t waitq;
+	DECLARE_WAITQUEUE(wait, current);
+
+	/*
+	 * This code was stol^H^H^H^Hinspired by mtdchar.c
+	 */
+	init_waitqueue_head(&waitq);
+
+	erase->mtd = mtd;
+	erase->callback = concat_erase_callback;
+	erase->priv = (unsigned long)&waitq;
+			
+	/*
+	 * FIXME: Allow INTERRUPTIBLE. Which means
+	 * not having the wait_queue head on the stack.
+	 */
+	err = mtd->erase(mtd, erase);
+	if (!err)
+	{
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		add_wait_queue(&waitq, &wait);
+		if (erase->state != MTD_ERASE_DONE && erase->state != MTD_ERASE_FAILED)
+			schedule();
+		remove_wait_queue(&waitq, &wait);
+		set_current_state(TASK_RUNNING);
+
+		err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
+	}
+	return err;
+}
+
+static int concat_erase (struct mtd_info *mtd, struct erase_info *instr)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	struct mtd_info *subdev;
+	int i, err;
+	u_int32_t length;
+	struct erase_info *erase;
+
+	if (!(mtd->flags & MTD_WRITEABLE))
+		return -EROFS;
+
+	if(instr->addr > concat->mtd.size)
+		return -EINVAL;
+
+	if(instr->len + instr->addr > concat->mtd.size)
+		return -EINVAL;
+
+	/*
+	 * Check for proper erase block alignment of the to-be-erased area.
+	 * It is easier to do this based on the super device's erase
+	 * region info rather than looking at each particular sub-device
+	 * in turn.
+	 */
+	if (!concat->mtd.numeraseregions)
+	{	/* the easy case: device has uniform erase block size */
+		if(instr->addr & (concat->mtd.erasesize - 1))
+			return -EINVAL;
+		if(instr->len & (concat->mtd.erasesize - 1))
+			return -EINVAL;
+	}
+	else
+	{	/* device has variable erase size */
+		struct mtd_erase_region_info *erase_regions = concat->mtd.eraseregions;
+
+		/*
+		 * Find the erase region where the to-be-erased area begins:
+		 */
+		for(i = 0; i < concat->mtd.numeraseregions && 
+		           instr->addr >= erase_regions[i].offset; i++)
+			;
+		--i;
+
+		/*
+		 * Now erase_regions[i] is the region in which the
+		 * to-be-erased area begins. Verify that the starting
+		 * offset is aligned to this region's erase size:
+		 */
+		if (instr->addr & (erase_regions[i].erasesize-1))
+			return -EINVAL;
+
+		/*
+		 * now find the erase region where the to-be-erased area ends:
+		 */
+		for(; i < concat->mtd.numeraseregions && 
+		      (instr->addr + instr->len) >=  erase_regions[i].offset ; ++i)
+			;
+		--i;
+		/*
+		 * check if the ending offset is aligned to this region's erase size
+		 */
+		if ((instr->addr + instr->len) & (erase_regions[i].erasesize-1))
+			return -EINVAL;
+	}
+
+	/* make a local copy of instr to avoid modifying the caller's struct */
+	erase = kmalloc(sizeof(struct erase_info),GFP_KERNEL);
+
+	if (!erase)
+		return -ENOMEM;
+
+	*erase = *instr;
+	length = instr->len;
+
+	/*
+	 * find the subdevice where the to-be-erased area begins, adjust
+	 * starting offset to be relative to the subdevice start
+	 */
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		subdev = concat->subdev[i];
+		if(subdev->size <= erase->addr)
+			erase->addr -= subdev->size;
+		else
+			break;
+    }
+	if(i >= concat->num_subdev)	/* must never happen since size */
+		BUG();					/* limit has been verified above */
+
+	/* now do the erase: */
+	err = 0;
+	for(;length > 0; i++)	/* loop for all subevices affected by this request */
+	{
+		subdev = concat->subdev[i];		/* get current subdevice */
+
+		/* limit length to subdevice's size: */
+		if(erase->addr + length > subdev->size)
+			erase->len = subdev->size - erase->addr;
+		else
+			erase->len = length;
+
+		if (!(subdev->flags & MTD_WRITEABLE))
+		{
+			err = -EROFS;
+			break;
+		}
+		length -= erase->len;
+		if ((err = concat_dev_erase(subdev, erase)))
+		{
+			if(err == -EINVAL)	/* sanity check: must never happen since */
+				BUG();			/* block alignment has been checked above */
+			break;
+		}
+		/*
+		 * erase->addr specifies the offset of the area to be
+		 * erased *within the current subdevice*. It can be
+		 * non-zero only the first time through this loop, i.e.
+		 * for the first subdevice where blocks need to be erased.
+		 * All the following erases must begin at the start of the
+		 * current subdevice, i.e. at offset zero.
+		 */
+		erase->addr = 0;
+	}
+	instr->state = MTD_ERASE_DONE;
+	if (instr->callback)
+		instr->callback(instr);
+	kfree(erase);
+	return err;
+}
+
+static int concat_lock (struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i, err = -EINVAL;
+
+	if ((len + ofs) > mtd->size) 
+		return -EINVAL;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		size_t size;
+
+		if (ofs >= subdev->size)
+		{
+			size  = 0;
+			ofs -= subdev->size;
+		}
+		else
+		{
+			if (ofs + len > subdev->size)
+				size = subdev->size - ofs;
+			else
+				size = len;
+
+			err = subdev->lock(subdev, ofs, size);
+
+			if(err)
+				break;
+
+			len -= size;
+			if(len == 0)
+				break;
+
+			err = -EINVAL;
+			ofs = 0;
+		}
+	}
+	return err;
+}
+
+static int concat_unlock (struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i, err = 0;
+
+	if ((len + ofs) > mtd->size) 
+		return -EINVAL;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		size_t size;
+
+		if (ofs >= subdev->size)
+		{
+			size  = 0;
+			ofs -= subdev->size;
+		}
+		else
+		{
+			if (ofs + len > subdev->size)
+				size = subdev->size - ofs;
+			else
+				size = len;
+
+			err = subdev->unlock(subdev, ofs, size);
+
+			if(err)
+				break;
+
+			len -= size;
+			if(len == 0)
+				break;
+
+			err = -EINVAL;
+			ofs = 0;
+		}
+	}
+	return err;
+}
+
+static void concat_sync(struct mtd_info *mtd)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		subdev->sync(subdev);
+	}
+}
+
+static int concat_suspend(struct mtd_info *mtd)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i, rc = 0;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		if((rc = subdev->suspend(subdev)) < 0)
+			return rc;
+	}
+	return rc;
+}
+
+static void concat_resume(struct mtd_info *mtd)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i;
+
+	for(i = 0; i < concat->num_subdev; i++)
+	{
+		struct mtd_info *subdev = concat->subdev[i];
+		subdev->resume(subdev);
+	}
+}
+
+/*
+ * This function constructs a virtual MTD device by concatenating
+ * num_devs MTD devices. A pointer to the new device object is
+ * stored to *new_dev upon success. This function does _not_
+ * register any devices: this is the caller's responsibility.
+ */
+struct mtd_info *mtd_concat_create(
+	struct mtd_info *subdev[],	/* subdevices to concatenate */
+	int num_devs,				/* number of subdevices      */
+	char *name)					/* name for the new device   */
+{
+	int i;
+	size_t size;
+	struct mtd_concat *concat;
+	u_int32_t max_erasesize, curr_erasesize;
+	int num_erase_region;
+
+	printk(KERN_NOTICE "Concatenating MTD devices:\n");
+	for(i = 0; i < num_devs; i++)
+		printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
+	printk(KERN_NOTICE "into device \"%s\"\n", name);
+
+	/* allocate the device structure */
+	size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
+	concat = kmalloc (size, GFP_KERNEL);
+	if(!concat)
+	{
+		printk ("memory allocation error while creating concatenated device \"%s\"\n",
+				name);
+			return NULL;
+	}
+	memset(concat, 0, size);
+	concat->subdev = (struct mtd_info **)(concat + 1);
+
+	/*
+	 * Set up the new "super" device's MTD object structure, check for
+	 * incompatibilites between the subdevices.
+	 */
+	concat->mtd.type      = subdev[0]->type;
+	concat->mtd.flags     = subdev[0]->flags;
+	concat->mtd.size      = subdev[0]->size;
+	concat->mtd.erasesize = subdev[0]->erasesize;
+	concat->mtd.oobblock  = subdev[0]->oobblock;
+	concat->mtd.oobsize   = subdev[0]->oobsize;
+	concat->mtd.ecctype   = subdev[0]->ecctype;
+	concat->mtd.eccsize   = subdev[0]->eccsize;
+
+	concat->subdev[0]   = subdev[0];
+
+	for(i = 1; i < num_devs; i++)
+	{
+		if(concat->mtd.type != subdev[i]->type)
+		{
+			kfree(concat);
+			printk ("Incompatible device type on \"%s\"\n", subdev[i]->name);
+			return NULL;
+		}
+		if(concat->mtd.flags != subdev[i]->flags)
+		{	/*
+			 * Expect all flags except MTD_WRITEABLE to be equal on
+			 * all subdevices.
+			 */
+			if((concat->mtd.flags ^ subdev[i]->flags) & ~MTD_WRITEABLE)
+			{
+				kfree(concat);
+				printk ("Incompatible device flags on \"%s\"\n", subdev[i]->name);
+				return NULL;
+			}
+			else	/* if writeable attribute differs, make super device writeable */
+				concat->mtd.flags |= subdev[i]->flags & MTD_WRITEABLE;
+		}
+		concat->mtd.size += subdev[i]->size;
+		if(concat->mtd.oobblock != subdev[i]->oobblock ||
+		   concat->mtd.oobsize  != subdev[i]->oobsize  ||
+		   concat->mtd.ecctype  != subdev[i]->ecctype  ||
+		   concat->mtd.eccsize  != subdev[i]->eccsize)
+		{
+			kfree(concat);
+			printk ("Incompatible OOB or ECC data on \"%s\"\n", subdev[i]->name);
+			return NULL;
+		}
+		concat->subdev[i] = subdev[i];
+		
+	}
+
+	concat->num_subdev  = num_devs;
+	concat->mtd.name    = name;
+
+	/*
+	 * NOTE: for now, we do not provide any readv()/writev() methods
+	 *       because they are messy to implement and they are not
+	 *       used to a great extent anyway.
+	 */
+	concat->mtd.erase   = concat_erase;
+	concat->mtd.read    = concat_read;
+	concat->mtd.write   = concat_write;
+	concat->mtd.sync    = concat_sync;
+	concat->mtd.lock    = concat_lock;
+	concat->mtd.unlock  = concat_unlock;
+	concat->mtd.suspend = concat_suspend;
+	concat->mtd.resume  = concat_resume;
+
+
+	/*
+	 * Combine the erase block size info of the subdevices:
+	 *
+	 * first, walk the map of the new device and see how
+	 * many changes in erase size we have
+	 */
+	max_erasesize = curr_erasesize = subdev[0]->erasesize;
+	num_erase_region = 1;
+	for(i = 0; i < num_devs; i++)
+	{
+		if(subdev[i]->numeraseregions == 0)
+		{	/* current subdevice has uniform erase size */
+			if(subdev[i]->erasesize != curr_erasesize)
+			{	/* if it differs from the last subdevice's erase size, count it */
+				++num_erase_region;
+				curr_erasesize = subdev[i]->erasesize;
+				if(curr_erasesize > max_erasesize)
+					max_erasesize = curr_erasesize;
+			}
+		}
+		else
+		{	/* current subdevice has variable erase size */
+			int j;
+			for(j = 0; j < subdev[i]->numeraseregions; j++)
+			{	/* walk the list of erase regions, count any changes */
+				if(subdev[i]->eraseregions[j].erasesize != curr_erasesize)
+				{
+					++num_erase_region;
+					curr_erasesize = subdev[i]->eraseregions[j].erasesize;
+					if(curr_erasesize > max_erasesize)
+						max_erasesize = curr_erasesize;
+				}
+			}
+		}
+	}
+
+	if(num_erase_region == 1)
+	{	/*
+		 * All subdevices have the same uniform erase size.
+		 * This is easy:
+		 */
+		concat->mtd.erasesize = curr_erasesize;
+		concat->mtd.numeraseregions = 0;
+	}
+	else
+	{	/*
+		 * erase block size varies across the subdevices: allocate
+		 * space to store the data describing the variable erase regions
+		 */
+		struct mtd_erase_region_info *erase_region_p;
+		u_int32_t begin, position;
+
+		concat->mtd.erasesize = max_erasesize;
+		concat->mtd.numeraseregions = num_erase_region;
+		concat->mtd.eraseregions = erase_region_p = kmalloc (
+		     num_erase_region * sizeof(struct mtd_erase_region_info), GFP_KERNEL);
+		if(!erase_region_p)
+		{
+			kfree(concat);
+			printk ("memory allocation error while creating erase region list"
+			        " for device \"%s\"\n", name);
+			return NULL;
+		}
+
+		/*
+		 * walk the map of the new device once more and fill in
+		 * in erase region info:
+		 */
+		curr_erasesize = subdev[0]->erasesize;
+		begin = position = 0;
+		for(i = 0; i < num_devs; i++)
+		{
+			if(subdev[i]->numeraseregions == 0)
+			{	/* current subdevice has uniform erase size */
+				if(subdev[i]->erasesize != curr_erasesize)
+				{	/*
+					 *  fill in an mtd_erase_region_info structure for the area
+					 *  we have walked so far:
+					 */
+					erase_region_p->offset    = begin;
+					erase_region_p->erasesize = curr_erasesize;
+					erase_region_p->numblocks = (position - begin) / curr_erasesize;
+					begin = position;
+
+					curr_erasesize = subdev[i]->erasesize;
+					++erase_region_p;
+				}
+				position += subdev[i]->size;
+			}
+			else
+			{	/* current subdevice has variable erase size */
+				int j;
+				for(j = 0; j < subdev[i]->numeraseregions; j++)
+				{	/* walk the list of erase regions, count any changes */
+					if(subdev[i]->eraseregions[j].erasesize != curr_erasesize)
+					{
+						erase_region_p->offset    = begin;
+						erase_region_p->erasesize = curr_erasesize;
+						erase_region_p->numblocks = (position - begin) / curr_erasesize;
+						begin = position;
+
+						curr_erasesize = subdev[i]->eraseregions[j].erasesize;
+						++erase_region_p;
+					}
+					position += subdev[i]->eraseregions[j].numblocks * curr_erasesize;
+				}
+			}
+		}
+		/* Now write the final entry */
+		erase_region_p->offset    = begin;
+		erase_region_p->erasesize = curr_erasesize;
+		erase_region_p->numblocks = (position - begin) / curr_erasesize;
+	}
+
+	return &concat->mtd;
+}
+
+/* 
+ * This function destroys an MTD object obtained from concat_mtd_devs()
+ */
+
+void mtd_concat_destroy(struct mtd_info *mtd)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	if(concat->mtd.numeraseregions)
+		kfree(concat->mtd.eraseregions);
+	kfree(concat);
+}
+
+
+EXPORT_SYMBOL(mtd_concat_create);
+EXPORT_SYMBOL(mtd_concat_destroy);
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
+MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");