The mtd concat layer supports concatenating several MTD devices
into a single one. This is nearly as-is from the corresponding
Kernel code.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/mtd/Kconfig | 10 +
drivers/mtd/Makefile | 1 +
drivers/mtd/mtdconcat.c | 765 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/concat.h | 34 ++
4 files changed, 810 insertions(+)
create mode 100644 drivers/mtd/mtdconcat.c
create mode 100644 include/linux/mtd/concat.h
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 49ea88c..ea1be55 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -20,6 +20,16 @@ config MTD_RAW_DEVICE
default n
prompt "mtdraw device to read/write both data+oob"
+config MTD_CONCAT
+ bool
+ prompt "MTD concatenating support"
+ help
+ Support for concatenating several MTD devices into a single
+ (virtual) one. This allows you to have -for example- a JFFS(2)
+ file system spanning multiple physical flash chips. This option
+ needs driver support, currently only the cfi-flash driver supports
+ concatenating MTD devices.
+
source "drivers/mtd/devices/Kconfig"
source "drivers/mtd/nor/Kconfig"
source "drivers/mtd/nand/Kconfig"
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 148ec6c..d3ae7fc 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -6,3 +6,4 @@ obj-y += devices/
obj-$(CONFIG_MTD) += core.o partition.o
obj-$(CONFIG_MTD_OOB_DEVICE) += mtdoob.o
obj-$(CONFIG_MTD_RAW_DEVICE) += mtdraw.o
+obj-$(CONFIG_MTD_CONCAT) += mtdconcat.o
diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
new file mode 100644
index 0000000..58cb126
--- /dev/null
+++ b/drivers/mtd/mtdconcat.c
@@ -0,0 +1,765 @@
+/*
+ * MTD device concatenation layer
+ *
+ * Copyright © 2002 Robert Kaiser <rkaiser@xxxxxxxx>
+ * Copyright © 2002-2010 David Woodhouse <dwmw2@xxxxxxxxxxxxx>
+ *
+ * NAND support by Christian Gan <cgan@xxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+#include <common.h>
+#include <malloc.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/concat.h>
+
+#include <asm-generic/div64.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 ret = 0, err;
+ int i;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+ size_t size, retsize;
+
+ if (from >= subdev->size) {
+ /* Not destined for this subdev */
+ size = 0;
+ from -= subdev->size;
+ continue;
+ }
+ if (from + len > subdev->size)
+ /* First part goes into this subdev */
+ size = subdev->size - from;
+ else
+ /* Entire transaction goes into this subdev */
+ size = len;
+
+ err = mtd_read(subdev, from, size, &retsize, buf);
+
+ /* Save information about bitflips! */
+ if (unlikely(err)) {
+ if (mtd_is_eccerr(err)) {
+ mtd->ecc_stats.failed++;
+ ret = err;
+ } else if (mtd_is_bitflip(err)) {
+ mtd->ecc_stats.corrected++;
+ /* Do not overwrite -EBADMSG !! */
+ if (!ret)
+ ret = err;
+ } else
+ return err;
+ }
+
+ *retlen += retsize;
+ len -= size;
+ if (len == 0)
+ return ret;
+
+ buf += size;
+ from = 0;
+ }
+ return -EINVAL;
+}
+
+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;
+
+ 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;
+ continue;
+ }
+ if (to + len > subdev->size)
+ size = subdev->size - to;
+ else
+ size = len;
+
+ err = mtd_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 int
+concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
+{
+ struct mtd_concat *concat = CONCAT(mtd);
+ struct mtd_oob_ops devops = *ops;
+ int i, err, ret = 0;
+
+ ops->retlen = ops->oobretlen = 0;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+
+ if (from >= subdev->size) {
+ from -= subdev->size;
+ continue;
+ }
+
+ /* partial read ? */
+ if (from + devops.len > subdev->size)
+ devops.len = subdev->size - from;
+
+ err = mtd_read_oob(subdev, from, &devops);
+ ops->retlen += devops.retlen;
+ ops->oobretlen += devops.oobretlen;
+
+ /* Save information about bitflips! */
+ if (unlikely(err)) {
+ if (mtd_is_eccerr(err)) {
+ mtd->ecc_stats.failed++;
+ ret = err;
+ } else if (mtd_is_bitflip(err)) {
+ mtd->ecc_stats.corrected++;
+ /* Do not overwrite -EBADMSG !! */
+ if (!ret)
+ ret = err;
+ } else
+ return err;
+ }
+
+ if (devops.datbuf) {
+ devops.len = ops->len - ops->retlen;
+ if (!devops.len)
+ return ret;
+ devops.datbuf += devops.retlen;
+ }
+ if (devops.oobbuf) {
+ devops.ooblen = ops->ooblen - ops->oobretlen;
+ if (!devops.ooblen)
+ return ret;
+ devops.oobbuf += ops->oobretlen;
+ }
+
+ from = 0;
+ }
+ return -EINVAL;
+}
+
+static int
+concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
+{
+ struct mtd_concat *concat = CONCAT(mtd);
+ struct mtd_oob_ops devops = *ops;
+ int i, err;
+
+ if (!(mtd->flags & MTD_WRITEABLE))
+ return -EROFS;
+
+ ops->retlen = ops->oobretlen = 0;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+
+ if (to >= subdev->size) {
+ to -= subdev->size;
+ continue;
+ }
+
+ /* partial write ? */
+ if (to + devops.len > subdev->size)
+ devops.len = subdev->size - to;
+
+ err = mtd_write_oob(subdev, to, &devops);
+ ops->retlen += devops.retlen;
+ ops->oobretlen += devops.oobretlen;
+ if (err)
+ return err;
+
+ if (devops.datbuf) {
+ devops.len = ops->len - ops->retlen;
+ if (!devops.len)
+ return 0;
+ devops.datbuf += devops.retlen;
+ }
+ if (devops.oobbuf) {
+ devops.ooblen = ops->ooblen - ops->oobretlen;
+ if (!devops.ooblen)
+ return 0;
+ devops.oobbuf += devops.oobretlen;
+ }
+ to = 0;
+ }
+ return -EINVAL;
+}
+
+static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
+{
+ int err;
+ wait_queue_head_t waitq;
+
+ erase->mtd = mtd;
+ erase->priv = (unsigned long) &waitq;
+
+ err = mtd_erase(mtd, erase);
+
+ 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;
+ uint64_t length, offset = 0;
+ struct erase_info *erase;
+
+ /*
+ * 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 (i < 0 || 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 (i < 0 || ((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;
+ offset += subdev->size;
+ } else {
+ break;
+ }
+ }
+
+ /* must never happen since size limit has been verified above */
+ BUG_ON(i >= concat->num_subdev);
+
+ /* now do the erase: */
+ err = 0;
+ for (; length > 0; i++) {
+ /* loop for all subdevices 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;
+
+ length -= erase->len;
+ if ((err = concat_dev_erase(subdev, erase))) {
+ /* sanity check: should never happen since
+ * block alignment has been checked above */
+ BUG_ON(err == -EINVAL);
+ if (erase->fail_addr != 0xffffffff)
+ instr->fail_addr = erase->fail_addr + offset;
+ 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;
+ offset += subdev->size;
+ }
+ instr->state = erase->state;
+ kfree(erase);
+ if (err)
+ return err;
+
+ if (instr->callback)
+ instr->callback(instr);
+ return 0;
+}
+
+static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+ struct mtd_concat *concat = CONCAT(mtd);
+ int i, err = -EINVAL;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+ uint64_t size;
+
+ if (ofs >= subdev->size) {
+ size = 0;
+ ofs -= subdev->size;
+ continue;
+ }
+ if (ofs + len > subdev->size)
+ size = subdev->size - ofs;
+ else
+ size = len;
+
+ err = mtd_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;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+ uint64_t size;
+
+ if (ofs >= subdev->size) {
+ size = 0;
+ ofs -= subdev->size;
+ continue;
+ }
+ if (ofs + len > subdev->size)
+ size = subdev->size - ofs;
+ else
+ size = len;
+
+ err = mtd_unlock(subdev, ofs, size);
+ if (err)
+ break;
+
+ len -= size;
+ if (len == 0)
+ break;
+
+ err = -EINVAL;
+ ofs = 0;
+ }
+
+ return err;
+}
+
+static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
+{
+ struct mtd_concat *concat = CONCAT(mtd);
+ int i, res = 0;
+
+ if (!mtd_can_have_bb(concat->subdev[0]))
+ return res;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+
+ if (ofs >= subdev->size) {
+ ofs -= subdev->size;
+ continue;
+ }
+
+ res = mtd_block_isbad(subdev, ofs);
+ break;
+ }
+
+ return res;
+}
+
+static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
+{
+ struct mtd_concat *concat = CONCAT(mtd);
+ int i, err = -EINVAL;
+
+ for (i = 0; i < concat->num_subdev; i++) {
+ struct mtd_info *subdev = concat->subdev[i];
+
+ if (ofs >= subdev->size) {
+ ofs -= subdev->size;
+ continue;
+ }
+
+ err = mtd_block_markbad(subdev, ofs);
+ if (!err)
+ mtd->ecc_stats.badblocks++;
+ break;
+ }
+
+ return err;
+}
+
+/*
+ * 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 */
+ const char *name)
+{ /* name for the new device */
+ int i;
+ size_t size;
+ struct mtd_concat *concat;
+ uint32_t max_erasesize, curr_erasesize;
+ int num_erase_region;
+ int max_writebufsize = 0;
+
+ 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 = kzalloc(size, GFP_KERNEL);
+ if (!concat) {
+ printk
+ ("memory allocation error while creating concatenated device \"%s\"\n",
+ name);
+ return NULL;
+ }
+ concat->subdev = (struct mtd_info **) (concat + 1);
+
+ /*
+ * Set up the new "super" device's MTD object structure, check for
+ * incompatibilities 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.writesize = subdev[0]->writesize;
+
+ for (i = 0; i < num_devs; i++)
+ if (max_writebufsize < subdev[i]->writebufsize)
+ max_writebufsize = subdev[i]->writebufsize;
+ concat->mtd.writebufsize = max_writebufsize;
+
+ concat->mtd.subpage_sft = subdev[0]->subpage_sft;
+ concat->mtd.oobsize = subdev[0]->oobsize;
+ concat->mtd.oobavail = subdev[0]->oobavail;
+ if (subdev[0]->read_oob)
+ concat->mtd.read_oob = concat_read_oob;
+ if (subdev[0]->write_oob)
+ concat->mtd.write_oob = concat_write_oob;
+ if (subdev[0]->block_isbad)
+ concat->mtd.block_isbad = concat_block_isbad;
+ if (subdev[0]->block_markbad)
+ concat->mtd.block_markbad = concat_block_markbad;
+
+ concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
+
+ 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;
+ concat->mtd.ecc_stats.badblocks +=
+ subdev[i]->ecc_stats.badblocks;
+ if (concat->mtd.writesize != subdev[i]->writesize ||
+ concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
+ concat->mtd.oobsize != subdev[i]->oobsize ||
+ !concat->mtd.read_oob != !subdev[i]->read_oob ||
+ !concat->mtd.write_oob != !subdev[i]->write_oob) {
+ kfree(concat);
+ printk("Incompatible OOB or ECC data on \"%s\"\n",
+ subdev[i]->name);
+ return NULL;
+ }
+ concat->subdev[i] = subdev[i];
+
+ }
+
+ concat->mtd.ecclayout = subdev[0]->ecclayout;
+
+ concat->num_subdev = num_devs;
+ concat->mtd.name = name;
+
+ concat->mtd.erase = concat_erase;
+ concat->mtd.read = concat_read;
+ concat->mtd.write = concat_write;
+ concat->mtd.lock = concat_lock;
+ concat->mtd.unlock = concat_unlock;
+
+ /*
+ * 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 {
+ uint64_t tmp64;
+
+ /*
+ * 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;
+ uint64_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;
+ tmp64 = position - begin;
+ do_div(tmp64, curr_erasesize);
+ erase_region_p->numblocks = tmp64;
+ 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;
+ tmp64 = position - begin;
+ do_div(tmp64, curr_erasesize);
+ erase_region_p->numblocks = tmp64;
+ begin = position;
+
+ curr_erasesize =
+ subdev[i]->eraseregions[j].
+ erasesize;
+ ++erase_region_p;
+ }
+ position +=
+ subdev[i]->eraseregions[j].
+ numblocks * (uint64_t)curr_erasesize;
+ }
+ }
+ }
+ /* Now write the final entry */
+ erase_region_p->offset = begin;
+ erase_region_p->erasesize = curr_erasesize;
+ tmp64 = position - begin;
+ do_div(tmp64, curr_erasesize);
+ erase_region_p->numblocks = tmp64;
+ }
+
+ 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);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Kaiser <rkaiser@xxxxxxxx>");
+MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");
diff --git a/include/linux/mtd/concat.h b/include/linux/mtd/concat.h
new file mode 100644
index 0000000..ccdbe93
--- /dev/null
+++ b/include/linux/mtd/concat.h
@@ -0,0 +1,34 @@
+/*
+ * MTD device concatenation layer definitions
+ *
+ * Copyright © 2002 Robert Kaiser <rkaiser@xxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifndef MTD_CONCAT_H
+#define MTD_CONCAT_H
+
+
+struct mtd_info *mtd_concat_create(
+ struct mtd_info *subdev[], /* subdevices to concatenate */
+ int num_devs, /* number of subdevices */
+ const char *name); /* name for the new device */
+
+void mtd_concat_destroy(struct mtd_info *mtd);
+
+#endif
+
--
2.1.4
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