Merge branch 'Makefile' of git://git.denx.de/u-boot-arm
[platform/kernel/u-boot.git] / drivers / mtd / nand / nand_util.c
index 4fd4e16..22820d5 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * drivers/nand/nand_util.c
+ * drivers/mtd/nand/nand_util.c
  *
  * Copyright (C) 2006 by Weiss-Electronic GmbH.
  * All rights reserved.
  */
 
 #include <common.h>
-
-#if defined(CONFIG_CMD_NAND) && !defined(CFG_NAND_LEGACY)
-
 #include <command.h>
 #include <watchdog.h>
 #include <malloc.h>
 #include <div64.h>
 
+
+#include <asm/errno.h>
+#include <linux/mtd/mtd.h>
 #include <nand.h>
 #include <jffs2/jffs2.h>
 
@@ -69,71 +69,33 @@ static int nand_block_bad_scrub(struct mtd_info *mtd, loff_t ofs, int getchip)
 int nand_erase_opts(nand_info_t *meminfo, const nand_erase_options_t *opts)
 {
        struct jffs2_unknown_node cleanmarker;
-       int clmpos = 0;
-       int clmlen = 8;
        erase_info_t erase;
        ulong erase_length;
-       int isNAND;
        int bbtest = 1;
        int result;
        int percent_complete = -1;
        int (*nand_block_bad_old)(struct mtd_info *, loff_t, int) = NULL;
        const char *mtd_device = meminfo->name;
+       struct mtd_oob_ops oob_opts;
+       struct nand_chip *chip = meminfo->priv;
+       uint8_t buf[64];
 
+       memset(buf, 0, sizeof(buf));
        memset(&erase, 0, sizeof(erase));
+       memset(&oob_opts, 0, sizeof(oob_opts));
 
        erase.mtd = meminfo;
        erase.len  = meminfo->erasesize;
        erase.addr = opts->offset;
        erase_length = opts->length;
 
-       isNAND = meminfo->type == MTD_NANDFLASH ? 1 : 0;
-
-       if (opts->jffs2) {
-               cleanmarker.magic = cpu_to_je16 (JFFS2_MAGIC_BITMASK);
-               cleanmarker.nodetype = cpu_to_je16 (JFFS2_NODETYPE_CLEANMARKER);
-               if (isNAND) {
-                       struct nand_oobinfo *oobinfo = &meminfo->oobinfo;
-
-                       /* check for autoplacement */
-                       if (oobinfo->useecc == MTD_NANDECC_AUTOPLACE) {
-                               /* get the position of the free bytes */
-                               if (!oobinfo->oobfree[0][1]) {
-                                       printf(" Eeep. Autoplacement selected "
-                                              "and no empty space in oob\n");
-                                       return -1;
-                               }
-                               clmpos = oobinfo->oobfree[0][0];
-                               clmlen = oobinfo->oobfree[0][1];
-                               if (clmlen > 8)
-                                       clmlen = 8;
-                       } else {
-                               /* legacy mode */
-                               switch (meminfo->oobsize) {
-                               case 8:
-                                       clmpos = 6;
-                                       clmlen = 2;
-                                       break;
-                               case 16:
-                                       clmpos = 8;
-                                       clmlen = 8;
-                                       break;
-                               case 64:
-                                       clmpos = 16;
-                                       clmlen = 8;
-                                       break;
-                               }
-                       }
 
-                       cleanmarker.totlen = cpu_to_je32(8);
-               } else {
-                       cleanmarker.totlen =
-                               cpu_to_je32(sizeof(struct jffs2_unknown_node));
-               }
-               cleanmarker.hdr_crc =  cpu_to_je32(
-                       crc32_no_comp(0, (unsigned char *) &cleanmarker,
-                                     sizeof(struct jffs2_unknown_node) - 4));
-       }
+       cleanmarker.magic = cpu_to_je16 (JFFS2_MAGIC_BITMASK);
+       cleanmarker.nodetype = cpu_to_je16 (JFFS2_NODETYPE_CLEANMARKER);
+       cleanmarker.totlen = cpu_to_je32(8);
+       cleanmarker.hdr_crc = cpu_to_je32(
+       crc32_no_comp(0, (unsigned char *) &cleanmarker,
+       sizeof(struct jffs2_unknown_node) - 4));
 
        /* scrub option allows to erase badblock. To prevent internal
         * check from erase() method, set block check method to dummy
@@ -153,6 +115,13 @@ int nand_erase_opts(nand_info_t *meminfo, const nand_erase_options_t *opts)
                priv_nand->bbt = NULL;
        }
 
+       if (erase_length < meminfo->erasesize) {
+               printf("Warning: Erase size 0x%08lx smaller than one "  \
+                      "erase block 0x%08x\n",erase_length, meminfo->erasesize);
+               printf("         Erasing 0x%08x instead\n", meminfo->erasesize);
+               erase_length = meminfo->erasesize;
+       }
+
        for (;
             erase.addr < opts->offset + erase_length;
             erase.addr += meminfo->erasesize) {
@@ -187,25 +156,21 @@ int nand_erase_opts(nand_info_t *meminfo, const nand_erase_options_t *opts)
                /* format for JFFS2 ? */
                if (opts->jffs2) {
 
-                       /* write cleanmarker */
-                       if (isNAND) {
-                               size_t written;
-                               result = meminfo->write_oob(meminfo,
-                                                           erase.addr + clmpos,
-                                                           clmlen,
-                                                           &written,
-                                                           (unsigned char *)
-                                                           &cleanmarker);
-                               if (result != 0) {
-                                       printf("\n%s: MTD writeoob failure: %d\n",
-                                              mtd_device, result);
-                                       continue;
-                               }
-                       } else {
-                               printf("\n%s: this erase routine only supports"
-                                      " NAND devices!\n",
-                                      mtd_device);
+                       chip->ops.len = chip->ops.ooblen = 64;
+                       chip->ops.datbuf = NULL;
+                       chip->ops.oobbuf = buf;
+                       chip->ops.ooboffs = chip->badblockpos & ~0x01;
+
+                       result = meminfo->write_oob(meminfo,
+                                                       erase.addr + meminfo->oobsize,
+                                                       &chip->ops);
+                       if (result != 0) {
+                               printf("\n%s: MTD writeoob failure: %d\n",
+                               mtd_device, result);
+                               continue;
                        }
+                       else
+                               printf("%s: MTD writeoob at 0x%08x\n",mtd_device, erase.addr + meminfo->oobsize );
                }
 
                if (!opts->quiet) {
@@ -225,11 +190,11 @@ int nand_erase_opts(nand_info_t *meminfo, const nand_erase_options_t *opts)
                                percent_complete = percent;
 
                                printf("\rErasing at 0x%x -- %3d%% complete.",
-                                      erase.addr, percent);
+                               erase.addr, percent);
 
                                if (opts->jffs2 && result == 0)
-                                       printf(" Cleanmarker written at 0x%x.",
-                                              erase.addr);
+                               printf(" Cleanmarker written at 0x%x.",
+                               erase.addr);
                        }
                }
        }
@@ -246,6 +211,9 @@ int nand_erase_opts(nand_info_t *meminfo, const nand_erase_options_t *opts)
        return 0;
 }
 
+/* XXX U-BOOT XXX */
+#if 0
+
 #define MAX_PAGE_SIZE  2048
 #define MAX_OOB_SIZE   64
 
@@ -256,443 +224,29 @@ static unsigned char data_buf[MAX_PAGE_SIZE];
 static unsigned char oob_buf[MAX_OOB_SIZE];
 
 /* OOB layouts to pass into the kernel as default */
-static struct nand_oobinfo none_oobinfo = {
+static struct nand_ecclayout none_ecclayout = {
        .useecc = MTD_NANDECC_OFF,
 };
 
-static struct nand_oobinfo jffs2_oobinfo = {
+static struct nand_ecclayout jffs2_ecclayout = {
        .useecc = MTD_NANDECC_PLACE,
        .eccbytes = 6,
        .eccpos = { 0, 1, 2, 3, 6, 7 }
 };
 
-static struct nand_oobinfo yaffs_oobinfo = {
+static struct nand_ecclayout yaffs_ecclayout = {
        .useecc = MTD_NANDECC_PLACE,
        .eccbytes = 6,
        .eccpos = { 8, 9, 10, 13, 14, 15}
 };
 
-static struct nand_oobinfo autoplace_oobinfo = {
+static struct nand_ecclayout autoplace_ecclayout = {
        .useecc = MTD_NANDECC_AUTOPLACE
 };
+#endif
 
-/**
- * nand_write_opts: - write image to NAND flash with support for various options
- *
- * @param meminfo      NAND device to erase
- * @param opts         write options (@see nand_write_options)
- * @return             0 in case of success
- *
- * This code is ported from nandwrite.c from Linux mtd utils by
- * Steven J. Hill and Thomas Gleixner.
- */
-int nand_write_opts(nand_info_t *meminfo, const nand_write_options_t *opts)
-{
-       int imglen = 0;
-       int pagelen;
-       int baderaseblock;
-       int blockstart = -1;
-       loff_t offs;
-       int readlen;
-       int oobinfochanged = 0;
-       int percent_complete = -1;
-       struct nand_oobinfo old_oobinfo;
-       ulong mtdoffset = opts->offset;
-       ulong erasesize_blockalign;
-       u_char *buffer = opts->buffer;
-       size_t written;
-       int result;
-
-       if (opts->pad && opts->writeoob) {
-               printf("Can't pad when oob data is present.\n");
-               return -1;
-       }
-
-       /* set erasesize to specified number of blocks - to match
-        * jffs2 (virtual) block size */
-       if (opts->blockalign == 0) {
-               erasesize_blockalign = meminfo->erasesize;
-       } else {
-               erasesize_blockalign = meminfo->erasesize * opts->blockalign;
-       }
-
-       /* make sure device page sizes are valid */
-       if (!(meminfo->oobsize == 16 && meminfo->oobblock == 512)
-           && !(meminfo->oobsize == 8 && meminfo->oobblock == 256)
-           && !(meminfo->oobsize == 64 && meminfo->oobblock == 2048)) {
-               printf("Unknown flash (not normal NAND)\n");
-               return -1;
-       }
-
-       /* read the current oob info */
-       memcpy(&old_oobinfo, &meminfo->oobinfo, sizeof(old_oobinfo));
-
-       /* write without ecc? */
-       if (opts->noecc) {
-               memcpy(&meminfo->oobinfo, &none_oobinfo,
-                      sizeof(meminfo->oobinfo));
-               oobinfochanged = 1;
-       }
-
-       /* autoplace ECC? */
-       if (opts->autoplace && (old_oobinfo.useecc != MTD_NANDECC_AUTOPLACE)) {
-
-               memcpy(&meminfo->oobinfo, &autoplace_oobinfo,
-                      sizeof(meminfo->oobinfo));
-               oobinfochanged = 1;
-       }
-
-       /* force OOB layout for jffs2 or yaffs? */
-       if (opts->forcejffs2 || opts->forceyaffs) {
-               struct nand_oobinfo *oobsel =
-                       opts->forcejffs2 ? &jffs2_oobinfo : &yaffs_oobinfo;
-
-               if (meminfo->oobsize == 8) {
-                       if (opts->forceyaffs) {
-                               printf("YAFSS cannot operate on "
-                                      "256 Byte page size\n");
-                               goto restoreoob;
-                       }
-                       /* Adjust number of ecc bytes */
-                       jffs2_oobinfo.eccbytes = 3;
-               }
-
-               memcpy(&meminfo->oobinfo, oobsel, sizeof(meminfo->oobinfo));
-       }
-
-       /* get image length */
-       imglen = opts->length;
-       pagelen = meminfo->oobblock
-               + ((opts->writeoob != 0) ? meminfo->oobsize : 0);
-
-       /* check, if file is pagealigned */
-       if ((!opts->pad) && ((imglen % pagelen) != 0)) {
-               printf("Input block length is not page aligned\n");
-               goto restoreoob;
-       }
-
-       /* check, if length fits into device */
-       if (((imglen / pagelen) * meminfo->oobblock)
-            > (meminfo->size - opts->offset)) {
-               printf("Image %d bytes, NAND page %d bytes, "
-                      "OOB area %u bytes, device size %u bytes\n",
-                      imglen, pagelen, meminfo->oobblock, meminfo->size);
-               printf("Input block does not fit into device\n");
-               goto restoreoob;
-       }
-
-       if (!opts->quiet)
-               printf("\n");
-
-       /* get data from input and write to the device */
-       while (imglen && (mtdoffset < meminfo->size)) {
-
-               WATCHDOG_RESET ();
-
-               /*
-                * new eraseblock, check for bad block(s). Stay in the
-                * loop to be sure if the offset changes because of
-                * a bad block, that the next block that will be
-                * written to is also checked. Thus avoiding errors if
-                * the block(s) after the skipped block(s) is also bad
-                * (number of blocks depending on the blockalign
-                */
-               while (blockstart != (mtdoffset & (~erasesize_blockalign+1))) {
-                       blockstart = mtdoffset & (~erasesize_blockalign+1);
-                       offs = blockstart;
-                       baderaseblock = 0;
-
-                       /* check all the blocks in an erase block for
-                        * bad blocks */
-                       do {
-                               int ret = meminfo->block_isbad(meminfo, offs);
-
-                               if (ret < 0) {
-                                       printf("Bad block check failed\n");
-                                       goto restoreoob;
-                               }
-                               if (ret == 1) {
-                                       baderaseblock = 1;
-                                       if (!opts->quiet)
-                                               printf("\rBad block at 0x%lx "
-                                                      "in erase block from "
-                                                      "0x%x will be skipped\n",
-                                                      (long) offs,
-                                                      blockstart);
-                               }
-
-                               if (baderaseblock) {
-                                       mtdoffset = blockstart
-                                               + erasesize_blockalign;
-                               }
-                               offs +=  erasesize_blockalign
-                                       / opts->blockalign;
-                       } while (offs < blockstart + erasesize_blockalign);
-               }
-
-               readlen = meminfo->oobblock;
-               if (opts->pad && (imglen < readlen)) {
-                       readlen = imglen;
-                       memset(data_buf + readlen, 0xff,
-                              meminfo->oobblock - readlen);
-               }
-
-               /* read page data from input memory buffer */
-               memcpy(data_buf, buffer, readlen);
-               buffer += readlen;
-
-               if (opts->writeoob) {
-                       /* read OOB data from input memory block, exit
-                        * on failure */
-                       memcpy(oob_buf, buffer, meminfo->oobsize);
-                       buffer += meminfo->oobsize;
-
-                       /* write OOB data first, as ecc will be placed
-                        * in there*/
-                       result = meminfo->write_oob(meminfo,
-                                                   mtdoffset,
-                                                   meminfo->oobsize,
-                                                   &written,
-                                                   (unsigned char *)
-                                                   &oob_buf);
-
-                       if (result != 0) {
-                               printf("\nMTD writeoob failure: %d\n",
-                                      result);
-                               goto restoreoob;
-                       }
-                       imglen -= meminfo->oobsize;
-               }
-
-               /* write out the page data */
-               result = meminfo->write(meminfo,
-                                       mtdoffset,
-                                       meminfo->oobblock,
-                                       &written,
-                                       (unsigned char *) &data_buf);
-
-               if (result != 0) {
-                       printf("writing NAND page at offset 0x%lx failed\n",
-                              mtdoffset);
-                       goto restoreoob;
-               }
-               imglen -= readlen;
-
-               if (!opts->quiet) {
-                       unsigned long long n = (unsigned long long)
-                                (opts->length-imglen) * 100;
-                       int percent;
-
-                       do_div(n, opts->length);
-                       percent = (int)n;
-
-                       /* output progress message only at whole percent
-                        * steps to reduce the number of messages printed
-                        * on (slow) serial consoles
-                        */
-                       if (percent != percent_complete) {
-                               printf("\rWriting data at 0x%x "
-                                      "-- %3d%% complete.",
-                                      mtdoffset, percent);
-                               percent_complete = percent;
-                       }
-               }
-
-               mtdoffset += meminfo->oobblock;
-       }
-
-       if (!opts->quiet)
-               printf("\n");
-
-restoreoob:
-       if (oobinfochanged) {
-               memcpy(&meminfo->oobinfo, &old_oobinfo,
-                      sizeof(meminfo->oobinfo));
-       }
-
-       if (imglen > 0) {
-               printf("Data did not fit into device, due to bad blocks\n");
-               return -1;
-       }
-
-       /* return happy */
-       return 0;
-}
-
-/**
- * nand_read_opts: - read image from NAND flash with support for various options
- *
- * @param meminfo      NAND device to erase
- * @param opts         read options (@see struct nand_read_options)
- * @return             0 in case of success
- *
- */
-int nand_read_opts(nand_info_t *meminfo, const nand_read_options_t *opts)
-{
-       int imglen = opts->length;
-       int pagelen;
-       int baderaseblock;
-       int blockstart = -1;
-       int percent_complete = -1;
-       loff_t offs;
-       size_t readlen;
-       ulong mtdoffset = opts->offset;
-       u_char *buffer = opts->buffer;
-       int result;
-
-       /* make sure device page sizes are valid */
-       if (!(meminfo->oobsize == 16 && meminfo->oobblock == 512)
-           && !(meminfo->oobsize == 8 && meminfo->oobblock == 256)
-           && !(meminfo->oobsize == 64 && meminfo->oobblock == 2048)) {
-               printf("Unknown flash (not normal NAND)\n");
-               return -1;
-       }
-
-       pagelen = meminfo->oobblock
-               + ((opts->readoob != 0) ? meminfo->oobsize : 0);
-
-       /* check, if length is not larger than device */
-       if (((imglen / pagelen) * meminfo->oobblock)
-            > (meminfo->size - opts->offset)) {
-               printf("Image %d bytes, NAND page %d bytes, "
-                      "OOB area %u bytes, device size %u bytes\n",
-                      imglen, pagelen, meminfo->oobblock, meminfo->size);
-               printf("Input block is larger than device\n");
-               return -1;
-       }
-
-       if (!opts->quiet)
-               printf("\n");
-
-       /* get data from input and write to the device */
-       while (imglen && (mtdoffset < meminfo->size)) {
-
-               WATCHDOG_RESET ();
-
-               /*
-                * new eraseblock, check for bad block(s). Stay in the
-                * loop to be sure if the offset changes because of
-                * a bad block, that the next block that will be
-                * written to is also checked. Thus avoiding errors if
-                * the block(s) after the skipped block(s) is also bad
-                * (number of blocks depending on the blockalign
-                */
-               while (blockstart != (mtdoffset & (~meminfo->erasesize+1))) {
-                       blockstart = mtdoffset & (~meminfo->erasesize+1);
-                       offs = blockstart;
-                       baderaseblock = 0;
-
-                       /* check all the blocks in an erase block for
-                        * bad blocks */
-                       do {
-                               int ret = meminfo->block_isbad(meminfo, offs);
-
-                               if (ret < 0) {
-                                       printf("Bad block check failed\n");
-                                       return -1;
-                               }
-                               if (ret == 1) {
-                                       baderaseblock = 1;
-                                       if (!opts->quiet)
-                                               printf("\rBad block at 0x%lx "
-                                                      "in erase block from "
-                                                      "0x%x will be skipped\n",
-                                                      (long) offs,
-                                                      blockstart);
-                               }
-
-                               if (baderaseblock) {
-                                       mtdoffset = blockstart
-                                               + meminfo->erasesize;
-                               }
-                               offs +=  meminfo->erasesize;
-
-                       } while (offs < blockstart + meminfo->erasesize);
-               }
-
-
-               /* read page data to memory buffer */
-               result = meminfo->read(meminfo,
-                                      mtdoffset,
-                                      meminfo->oobblock,
-                                      &readlen,
-                                      (unsigned char *) &data_buf);
-
-               if (result != 0) {
-                       printf("reading NAND page at offset 0x%lx failed\n",
-                              mtdoffset);
-                       return -1;
-               }
-
-               if (imglen < readlen) {
-                       readlen = imglen;
-               }
-
-               memcpy(buffer, data_buf, readlen);
-               buffer += readlen;
-               imglen -= readlen;
-
-               if (opts->readoob) {
-                       result = meminfo->read_oob(meminfo,
-                                                  mtdoffset,
-                                                  meminfo->oobsize,
-                                                  &readlen,
-                                                  (unsigned char *)
-                                                  &oob_buf);
-
-                       if (result != 0) {
-                               printf("\nMTD readoob failure: %d\n",
-                                      result);
-                               return -1;
-                       }
-
-
-                       if (imglen < readlen) {
-                               readlen = imglen;
-                       }
-
-                       memcpy(buffer, oob_buf, readlen);
-
-                       buffer += readlen;
-                       imglen -= readlen;
-               }
-
-               if (!opts->quiet) {
-                       unsigned long long n = (unsigned long long)
-                                (opts->length-imglen) * 100;
-                       int percent;
-
-                       do_div(n, opts->length);
-                       percent = (int)n;
-
-                       /* output progress message only at whole percent
-                        * steps to reduce the number of messages printed
-                        * on (slow) serial consoles
-                        */
-                       if (percent != percent_complete) {
-                       if (!opts->quiet)
-                               printf("\rReading data from 0x%x "
-                                      "-- %3d%% complete.",
-                                      mtdoffset, percent);
-                               percent_complete = percent;
-                       }
-               }
-
-               mtdoffset += meminfo->oobblock;
-       }
-
-       if (!opts->quiet)
-               printf("\n");
-
-       if (imglen > 0) {
-               printf("Could not read entire image due to bad blocks\n");
-               return -1;
-       }
-
-       /* return happy */
-       return 0;
-}
-
+/* XXX U-BOOT XXX */
+#if 0
 /******************************************************************************
  * Support for locking / unlocking operations of some NAND devices
  *****************************************************************************/
@@ -777,7 +331,7 @@ int nand_get_lock_status(nand_info_t *meminfo, ulong offset)
        this->select_chip(meminfo, chipnr);
 
 
-       if ((offset & (meminfo->oobblock - 1)) != 0) {
+       if ((offset & (meminfo->writesize - 1)) != 0) {
                printf ("nand_get_lock_status: "
                        "Start address must be beginning of "
                        "nand page!\n");
@@ -806,7 +360,7 @@ int nand_get_lock_status(nand_info_t *meminfo, ulong offset)
  * @param meminfo      nand mtd instance
  * @param start                start byte address
  * @param length       number of bytes to unlock (must be a multiple of
- *                     page size nand->oobblock)
+ *                     page size nand->writesize)
  *
  * @return             0 on success, -1 in case of error
  */
@@ -832,14 +386,14 @@ int nand_unlock(nand_info_t *meminfo, ulong start, ulong length)
                goto out;
        }
 
-       if ((start & (meminfo->oobblock - 1)) != 0) {
+       if ((start & (meminfo->writesize - 1)) != 0) {
                printf ("nand_unlock: Start address must be beginning of "
                        "nand page!\n");
                ret = -1;
                goto out;
        }
 
-       if (length == 0 || (length & (meminfo->oobblock - 1)) != 0) {
+       if (length == 0 || (length & (meminfo->writesize - 1)) != 0) {
                printf ("nand_unlock: Length must be a multiple of nand page "
                        "size!\n");
                ret = -1;
@@ -868,5 +422,184 @@ int nand_unlock(nand_info_t *meminfo, ulong start, ulong length)
        this->select_chip(meminfo, -1);
        return ret;
 }
-
 #endif
+
+/**
+ * get_len_incl_bad
+ *
+ * Check if length including bad blocks fits into device.
+ *
+ * @param nand NAND device
+ * @param offset offset in flash
+ * @param length image length
+ * @return image length including bad blocks
+ */
+static size_t get_len_incl_bad (nand_info_t *nand, size_t offset,
+                                const size_t length)
+{
+       size_t len_incl_bad = 0;
+       size_t len_excl_bad = 0;
+       size_t block_len;
+
+       while (len_excl_bad < length) {
+               block_len = nand->erasesize - (offset & (nand->erasesize - 1));
+
+               if (!nand_block_isbad (nand, offset & ~(nand->erasesize - 1)))
+                       len_excl_bad += block_len;
+
+               len_incl_bad += block_len;
+               offset       += block_len;
+
+               if ((offset + len_incl_bad) >= nand->size)
+                       break;
+       }
+
+       return len_incl_bad;
+}
+
+/**
+ * nand_write_skip_bad:
+ *
+ * Write image to NAND flash.
+ * Blocks that are marked bad are skipped and the is written to the next
+ * block instead as long as the image is short enough to fit even after
+ * skipping the bad blocks.
+ *
+ * @param nand         NAND device
+ * @param offset       offset in flash
+ * @param length       buffer length
+ * @param buf           buffer to read from
+ * @return             0 in case of success
+ */
+int nand_write_skip_bad(nand_info_t *nand, size_t offset, size_t *length,
+                        u_char *buffer)
+{
+       int rval;
+       size_t left_to_write = *length;
+       size_t len_incl_bad;
+       u_char *p_buffer = buffer;
+
+       /* Reject writes, which are not page aligned */
+       if ((offset & (nand->writesize - 1)) != 0 ||
+           (*length & (nand->writesize - 1)) != 0) {
+               printf ("Attempt to write non page aligned data\n");
+               return -EINVAL;
+       }
+
+       len_incl_bad = get_len_incl_bad (nand, offset, *length);
+
+       if ((offset + len_incl_bad) >= nand->size) {
+               printf ("Attempt to write outside the flash area\n");
+               return -EINVAL;
+       }
+
+       if (len_incl_bad == *length) {
+               rval = nand_write (nand, offset, length, buffer);
+               if (rval != 0) {
+                       printf ("NAND write to offset %x failed %d\n",
+                               offset, rval);
+                       return rval;
+               }
+       }
+
+       while (left_to_write > 0) {
+               size_t block_offset = offset & (nand->erasesize - 1);
+               size_t write_size;
+
+               if (nand_block_isbad (nand, offset & ~(nand->erasesize - 1))) {
+                       printf ("Skip bad block 0x%08x\n",
+                               offset & ~(nand->erasesize - 1));
+                       offset += nand->erasesize - block_offset;
+                       continue;
+               }
+
+               if (left_to_write < (nand->erasesize - block_offset))
+                       write_size = left_to_write;
+               else
+                       write_size = nand->erasesize - block_offset;
+
+               rval = nand_write (nand, offset, &write_size, p_buffer);
+               if (rval != 0) {
+                       printf ("NAND write to offset %x failed %d\n",
+                               offset, rval);
+                       *length -= left_to_write;
+                       return rval;
+               }
+
+               left_to_write -= write_size;
+               offset        += write_size;
+               p_buffer      += write_size;
+       }
+
+       return 0;
+}
+
+/**
+ * nand_read_skip_bad:
+ *
+ * Read image from NAND flash.
+ * Blocks that are marked bad are skipped and the next block is readen
+ * instead as long as the image is short enough to fit even after skipping the
+ * bad blocks.
+ *
+ * @param nand NAND device
+ * @param offset offset in flash
+ * @param length buffer length, on return holds remaining bytes to read
+ * @param buffer buffer to write to
+ * @return 0 in case of success
+ */
+int nand_read_skip_bad(nand_info_t *nand, size_t offset, size_t *length,
+                      u_char *buffer)
+{
+       int rval;
+       size_t left_to_read = *length;
+       size_t len_incl_bad;
+       u_char *p_buffer = buffer;
+
+       len_incl_bad = get_len_incl_bad (nand, offset, *length);
+
+       if ((offset + len_incl_bad) >= nand->size) {
+               printf ("Attempt to read outside the flash area\n");
+               return -EINVAL;
+       }
+
+       if (len_incl_bad == *length) {
+               rval = nand_read (nand, offset, length, buffer);
+               if (rval != 0) {
+                       printf ("NAND read from offset %x failed %d\n",
+                               offset, rval);
+                       return rval;
+               }
+       }
+
+       while (left_to_read > 0) {
+               size_t block_offset = offset & (nand->erasesize - 1);
+               size_t read_length;
+
+               if (nand_block_isbad (nand, offset & ~(nand->erasesize - 1))) {
+                       printf ("Skipping bad block 0x%08x\n",
+                               offset & ~(nand->erasesize - 1));
+                       offset += nand->erasesize - block_offset;
+                       continue;
+               }
+
+               if (left_to_read < (nand->erasesize - block_offset))
+                       read_length = left_to_read;
+               else
+                       read_length = nand->erasesize - block_offset;
+
+               rval = nand_read (nand, offset, &read_length, p_buffer);
+               if (rval != 0) {
+                       printf ("NAND read from offset %x failed %d\n",
+                               offset, rval);
+                       *length -= left_to_read;
+                       return rval;
+               }
+
+               left_to_read -= read_length;
+               offset       += read_length;
+               p_buffer     += read_length;
+       }
+
+       return 0;
+}