Hi Jagan, Shyam,

On 06/06/19 10:59, Shyam Saini wrote:
> Writing/updating boot image in nand device is not
> straight forward in i.MX6 platform and it requires
> boot control block(BCB) to be configured.
> 
> It becomes difficult to use uboot 'nand' command to
> write BCB since it requires platform specific attributes
> need to be taken care of.
> 
> It is even difficult to use existing msx-nand.c driver by
> incorporating BCB attributes like mxs_dma_desc does
> because it requires change in mtd and nand command.
> 
> So, cmd_nandbcb implemented in arch/arm/mach-imx
> 
> BCB contains two data structures, Firmware Configuration Block(FCB)
> and Discovered Bad Block Table(DBBT). FCB has nand timings,
> DBBT search area, page address of firmware.
> 
> On summary, nandbcb update will
> - erase the entire partition
> - create BCB by creating 2 FCB/DBBT block followed by
>   1 FW block based on partition size and erasesize.
> - fill FCB/DBBT structures
> - write FW/SPL on FW1
> - write FCB/DBBT in first 2 blocks
> 
> for nand boot, up on reset bootrom look for FCB structure in
> first block's if FCB found the nand timings are loaded for
> further reads. once FCB read done, DTTB will load and finally
> firmware will be loaded which is boot image.
> 
> Refer section "NAND Boot" from doc/imx/common/imx6.txt for more usage
> information.


Thanks for this work - this is still missing in current U-Boot. I will
merge this for the upcoming release - letting this in, we could win some
more testers helping to adjust if there are some issues.

Thanks again,
Stefano

> 
> Signed-off-by: Jagan Teki <ja...@amarulasolutions.com>
> Signed-off-by: Sergey Kubushyn <k...@koi8.net>
> Signed-off-by: Shyam Saini <shyam.sa...@amarulasolutions.com>
> ---
> Changes for v4:
> - Remove obselete apis and use bch_geometry structure for calculating
>   ecc level, bad block start bit and bad block byte
> - Write firmware only once
> - Shorten variable names
> - Update commit message
> - Update docs as per current patch
> - Fix checkpatch warnings
> Changes for v3:
> - Fixed multi-line comments
> - Better error handling for failed allocations
> Changes for v2:
> - Fixed commit message notes
> - Updated proper commit message
> - Update doc/README.imx6 with NAND boot details
> - Fixed long length variable names.
> - Fixed Gigantic variable name.
> - NULL checks for kzalloc
> - Move Kconfig option in separate patch
> - Fixed checkpatch warninigs
> ---
>  arch/arm/include/asm/mach-imx/imx-nandbcb.h        | 111 +++++++
>  .../arm/include/asm/mach-imx/mxs-nand.h            |   0
>  arch/arm/mach-imx/Makefile                         |   1 +
>  arch/arm/mach-imx/cmd_nandbcb.c                    | 369 
> +++++++++++++++++++++
>  doc/imx/common/imx6.txt                            |  75 +++++
>  drivers/mtd/nand/raw/mxs_nand.c                    |   2 +-
>  drivers/mtd/nand/raw/mxs_nand_spl.c                |   3 +-
>  7 files changed, 559 insertions(+), 2 deletions(-)
>  create mode 100644 arch/arm/include/asm/mach-imx/imx-nandbcb.h
>  rename drivers/mtd/nand/raw/mxs_nand.h => 
> arch/arm/include/asm/mach-imx/mxs-nand.h (100%)
>  create mode 100644 arch/arm/mach-imx/cmd_nandbcb.c
> 
> diff --git a/arch/arm/include/asm/mach-imx/imx-nandbcb.h 
> b/arch/arm/include/asm/mach-imx/imx-nandbcb.h
> new file mode 100644
> index 0000000000..033659a038
> --- /dev/null
> +++ b/arch/arm/include/asm/mach-imx/imx-nandbcb.h
> @@ -0,0 +1,111 @@
> +/*
> + * Copyright (C) 2017 Jagan Teki <ja...@amarulasolutions.com>
> + *
> + * SPDX-License-Identifier:  GPL-2.0+
> + */
> +
> +#ifndef _IMX_NAND_BCB_H_
> +#define _IMX_NAND_BCB_H_
> +
> +#define FCB_FINGERPRINT              0x20424346      /* 'FCB' */
> +#define FCB_VERSION_1                0x01000000
> +
> +#define DBBT_FINGERPRINT2    0x54424244      /* 'DBBT' */
> +#define DBBT_VERSION_1               0x01000000
> +
> +struct dbbt_block {
> +     u32 checksum;   /* reserved on i.MX6 */
> +     u32 fingerprint;
> +     u32 version;
> +     u32 numberbb;   /* reserved on i.MX6 */
> +     u32 dbbtpages;
> +};
> +
> +struct fcb_block {
> +     u32 checksum;           /* First fingerprint in first byte */
> +     u32 fingerprint;        /* 2nd fingerprint at byte 4 */
> +     u32 version;            /* 3rd fingerprint at byte 8 */
> +     u8 datasetup;
> +     u8 datahold;
> +     u8 addr_setup;
> +     u8 dsample_time;
> +
> +     /* These are for application use only and not for ROM. */
> +     u8 nandtiming;
> +     u8 rea;
> +     u8 rloh;
> +     u8 rhoh;
> +     u32 pagesize;           /* 2048 for 2K pages, 4096 for 4K pages */
> +     u32 oob_pagesize;       /* 2112 for 2K pages, 4314 for 4K pages */
> +     u32 sectors;            /* Number of 2K sections per block */
> +     u32 nr_nand;            /* Total Number of NANDs - not used by ROM */
> +     u32 nr_die;             /* Number of separate chips in this NAND */
> +     u32 celltype;           /* MLC or SLC */
> +     u32 ecc_type;           /* Type of ECC, can be one of BCH-0-20 */
> +     u32 ecc_nr;             /* Number of bytes for Block0 - BCH */
> +
> +     /* Block size in bytes for all blocks other than Block0 - BCH */
> +     u32 ecc_size;
> +     u32 ecc_level;          /* Ecc level for Block 0 - BCH */
> +     u32 meta_size;          /* Metadata size - BCH */
> +     /* Number of blocks per page for ROM use - BCH */
> +     u32 nr_blocks;
> +     u32 ecc_type_sdk;       /* Type of ECC, can be one of BCH-0-20 */
> +     u32 ecc_nr_sdk;         /* Number of bytes for Block0 - BCH */
> +     /* Block size in bytes for all blocks other than Block0 - BCH */
> +     u32 ecc_size_sdk;
> +     u32 ecc_level_sdk;      /* Ecc level for Block 0 - BCH */
> +     /* Number of blocks per page for SDK use - BCH */
> +     u32 nr_blocks_sdk;
> +     u32 meta_size_sdk;      /* Metadata size - BCH */
> +     u32 erase_th;           /* To set into BCH_MODE register */
> +
> +     /*
> +      * 0: normal boot
> +      * 1: to load patch starting next to FCB
> +      */
> +     u32 bootpatch;
> +     u32 patch_size; /* Size of patch in sectors */
> +     u32 fw1_start;  /* Firmware image starts on this sector */
> +     u32 fw2_start;  /* Secondary FW Image starting Sector */
> +     u32 fw1_pages;  /* Number of sectors in firmware image */
> +     u32 fw2_pages;  /* Number of sector in secondary FW image */
> +     u32 dbbt_start; /* Page address where dbbt search area begins */
> +
> +     /*
> +      * Byte in page data that have manufacturer marked bad block marker,
> +      * this will be swapped with metadata[0] to complete page data.
> +      */
> +     u32 bb_byte;
> +
> +     /*
> +      * For BCH ECC sizes other than 8 and 16 the bad block marker does not
> +      * start at 0th bit of bb_byte. This field is used to get to
> +      * the start bit of bad block marker byte with in bb_byte
> +      */
> +     u32 bb_start_bit;
> +
> +     /*
> +      * FCB value that gives byte offset for
> +      * bad block marker on physical NAND page
> +      */
> +     u32 phy_offset;
> +     u32 bchtype;
> +
> +     u32 readlatency;
> +     u32 predelay;
> +     u32 cedelay;
> +     u32 postdelay;
> +     u32 cmdaddpause;
> +     u32 datapause;
> +     u32 tmspeed;
> +     u32 busytimeout;
> +
> +     /* the flag to enable (1)/disable(0) bi swap */
> +     u32 disbbm;
> +
> +     /* The swap position of main area in spare area */
> +     u32 spare_offset;
> +};
> +
> +#endif       /* _IMX_NAND_BCB_H_ */
> diff --git a/drivers/mtd/nand/raw/mxs_nand.h 
> b/arch/arm/include/asm/mach-imx/mxs-nand.h
> similarity index 100%
> rename from drivers/mtd/nand/raw/mxs_nand.h
> rename to arch/arm/include/asm/mach-imx/mxs-nand.h
> diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
> index 37675d0558..e740d0c1e8 100644
> --- a/arch/arm/mach-imx/Makefile
> +++ b/arch/arm/mach-imx/Makefile
> @@ -59,6 +59,7 @@ ifneq ($(CONFIG_SPL_BUILD),y)
>  obj-$(CONFIG_CMD_BMODE) += cmd_bmode.o
>  obj-$(CONFIG_CMD_HDMIDETECT) += cmd_hdmidet.o
>  obj-$(CONFIG_CMD_DEKBLOB) += cmd_dek.o
> +obj-$(CONFIG_CMD_NANDBCB) += cmd_nandbcb.o
>  endif
>  
>  ifneq ($(CONFIG_BOARD_SIZE_LIMIT),)
> diff --git a/arch/arm/mach-imx/cmd_nandbcb.c b/arch/arm/mach-imx/cmd_nandbcb.c
> new file mode 100644
> index 0000000000..fd3df78fb4
> --- /dev/null
> +++ b/arch/arm/mach-imx/cmd_nandbcb.c
> @@ -0,0 +1,369 @@
> +/*
> + * i.MX6 nand boot control block(bcb).
> + *
> + * Based on the common/imx-bbu-nand-fcb.c from barebox and imx kobs-ng
> + *
> + * Copyright (C) 2017 Jagan Teki <ja...@amarulasolutions.com>
> + * Copyright (C) 2016 Sergey Kubushyn <k...@koi8.net>
> + *
> + * SPDX-License-Identifier:  GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <nand.h>
> +
> +#include <asm/io.h>
> +#include <jffs2/jffs2.h>
> +#include <linux/mtd/mtd.h>
> +
> +#include <asm/mach-imx/imx-nandbcb.h>
> +#include <asm/mach-imx/imximage.cfg>
> +#include <asm/mach-imx/mxs-nand.h>
> +#include <linux/mtd/mtd.h>
> +#include <nand.h>
> +
> +#define BF_VAL(v, bf)                (((v) & bf##_MASK) >> bf##_OFFSET)
> +#define GETBIT(v, n)         (((v) >> (n)) & 0x1)
> +
> +static u8 calculate_parity_13_8(u8 d)
> +{
> +     u8 p = 0;
> +
> +     p |= (GETBIT(d, 6) ^ GETBIT(d, 5) ^ GETBIT(d, 3) ^ GETBIT(d, 2)) << 0;
> +     p |= (GETBIT(d, 7) ^ GETBIT(d, 5) ^ GETBIT(d, 4) ^ GETBIT(d, 2) ^
> +           GETBIT(d, 1)) << 1;
> +     p |= (GETBIT(d, 7) ^ GETBIT(d, 6) ^ GETBIT(d, 5) ^ GETBIT(d, 1) ^
> +           GETBIT(d, 0)) << 2;
> +     p |= (GETBIT(d, 7) ^ GETBIT(d, 4) ^ GETBIT(d, 3) ^ GETBIT(d, 0)) << 3;
> +     p |= (GETBIT(d, 6) ^ GETBIT(d, 4) ^ GETBIT(d, 3) ^ GETBIT(d, 2) ^
> +           GETBIT(d, 1) ^ GETBIT(d, 0)) << 4;
> +
> +     return p;
> +}
> +
> +static void encode_hamming_13_8(void *_src, void *_ecc, size_t size)
> +{
> +     int i;
> +     u8 *src = _src;
> +     u8 *ecc = _ecc;
> +
> +     for (i = 0; i < size; i++)
> +             ecc[i] = calculate_parity_13_8(src[i]);
> +}
> +
> +static u32 calc_chksum(void *buf, size_t size)
> +{
> +     u32 chksum = 0;
> +     u8 *bp = buf;
> +     size_t i;
> +
> +     for (i = 0; i < size; i++)
> +             chksum += bp[i];
> +
> +     return ~chksum;
> +}
> +
> +static void fill_fcb(struct fcb_block *fcb, struct mtd_info *mtd)
> +{
> +     struct nand_chip *chip = mtd_to_nand(mtd);
> +     struct mxs_nand_info *nand_info = nand_get_controller_data(chip);
> +
> +     fcb->fingerprint = FCB_FINGERPRINT;
> +     fcb->version = FCB_VERSION_1;
> +     fcb->pagesize = mtd->writesize;
> +     fcb->oob_pagesize = mtd->writesize + mtd->oobsize;
> +     fcb->sectors = mtd->erasesize / mtd->writesize;
> +
> +     /* Divide ECC strength by two and save the value into FCB structure. */
> +     fcb->ecc_level = nand_info->bch_geometry.ecc_strength >> 1;
> +
> +     fcb->ecc_type = fcb->ecc_level;
> +
> +     /* Also hardcoded in kobs-ng */
> +     fcb->ecc_nr = 0x00000200;
> +     fcb->ecc_size = 0x00000200;
> +     fcb->datasetup = 80;
> +     fcb->datahold = 60;
> +     fcb->addr_setup = 25;
> +     fcb->dsample_time = 6;
> +     fcb->meta_size = 10;
> +
> +     /* DBBT search area starts at second page on first block */
> +     fcb->dbbt_start = 1;
> +
> +     fcb->bb_byte = nand_info->bch_geometry.block_mark_byte_offset;
> +     fcb->bb_start_bit = nand_info->bch_geometry.block_mark_bit_offset;
> +
> +     fcb->phy_offset = mtd->writesize;
> +
> +     fcb->nr_blocks = mtd->writesize / fcb->ecc_nr - 1;
> +
> +     fcb->checksum = calc_chksum((void *)fcb + 4, sizeof(*fcb) - 4);
> +}
> +
> +static int dbbt_fill_data(struct mtd_info *mtd, void *buf, int num_blocks)
> +{
> +     int n, n_bad_blocks = 0;
> +     u32 *bb = buf + 0x8;
> +     u32 *n_bad_blocksp = buf + 0x4;
> +
> +     for (n = 0; n < num_blocks; n++) {
> +             loff_t offset = n * mtd->erasesize;
> +                     if (mtd_block_isbad(mtd, offset)) {
> +                             n_bad_blocks++;
> +                             *bb = n;
> +                             bb++;
> +             }
> +     }
> +
> +     *n_bad_blocksp = n_bad_blocks;
> +
> +     return n_bad_blocks;
> +}
> +
> +static int nandbcb_update(struct mtd_info *mtd, loff_t off, size_t size,
> +                       size_t maxsize, const u_char *buf)
> +{
> +     nand_erase_options_t opts;
> +     struct fcb_block *fcb;
> +     struct dbbt_block *dbbt;
> +     loff_t fw1_off;
> +     void *fwbuf, *fcb_raw_page, *dbbt_page, *dbbt_data_page;
> +     int nr_blks, nr_blks_fcb, fw1_blk;
> +     size_t fwsize, dummy;
> +     int i, ret;
> +
> +     /* erase */
> +     memset(&opts, 0, sizeof(opts));
> +     opts.offset = off;
> +     opts.length = maxsize - 1;
> +     ret = nand_erase_opts(mtd, &opts);
> +     if (ret) {
> +             printf("%s: erase failed (ret = %d)\n", __func__, ret);
> +             return ret;
> +     }
> +
> +     /*
> +      * Reference documentation from i.MX6DQRM section 8.5.2.2
> +      *
> +      * Nand Boot Control Block(BCB) contains two data structures,
> +      * - Firmware Configuration Block(FCB)
> +      * - Discovered Bad Block Table(DBBT)
> +      *
> +      * FCB contains,
> +      * - nand timings
> +      * - DBBT search page address,
> +      * - start page address of primary firmware
> +      * - start page address of secondary firmware
> +      *
> +      * setup fcb:
> +      * - number of blocks = mtd partition size / mtd erasesize
> +      * - two firmware blocks, primary and secondary
> +      * - first 4 block for FCB/DBBT
> +      * - rest split in half for primary and secondary firmware
> +      * - same firmware will write two times
> +      */
> +     nr_blks_fcb = 2;
> +     nr_blks = maxsize / mtd->erasesize;
> +     fw1_blk = nr_blks_fcb;
> +
> +     /* write fw */
> +     fwsize = ALIGN(size + FLASH_OFFSET_STANDARD + mtd->writesize,
> +                    mtd->writesize);
> +     fwbuf = kzalloc(fwsize, GFP_KERNEL);
> +     if (!fwbuf) {
> +             debug("failed to allocate fwbuf\n");
> +             ret = -ENOMEM;
> +             goto err;
> +     }
> +
> +     memcpy(fwbuf + FLASH_OFFSET_STANDARD, buf, size);
> +     fw1_off = fw1_blk * mtd->erasesize;
> +     ret = nand_write_skip_bad(mtd, fw1_off, &fwsize, NULL, maxsize,
> +                               (u_char *)fwbuf, WITH_WR_VERIFY);
> +     printf("NAND fw write: 0x%llx offset, 0x%x bytes written: %s\n",
> +            fw1_off, fwsize, ret ? "ERROR" : "OK");
> +     if (ret)
> +             goto fwbuf_err;
> +
> +     /* fill fcb */
> +     fcb = kzalloc(sizeof(*fcb), GFP_KERNEL);
> +     if (!fcb) {
> +             debug("failed to allocate fcb\n");
> +             ret = -ENOMEM;
> +             goto fwbuf_err;
> +     }
> +
> +     fcb->fw1_start = (fw1_blk * mtd->erasesize) / mtd->writesize;
> +     fcb->fw1_pages = size / mtd->writesize + 1;
> +     fill_fcb(fcb, mtd);
> +
> +     /* fill dbbt */
> +     dbbt_page = kzalloc(mtd->writesize, GFP_KERNEL);
> +     if (!dbbt_page) {
> +             debug("failed to allocate dbbt_page\n");
> +             ret = -ENOMEM;
> +             goto fcb_err;
> +     }
> +
> +     dbbt_data_page = kzalloc(mtd->writesize, GFP_KERNEL);
> +     if (!dbbt_data_page) {
> +             debug("failed to allocate dbbt_data_page\n");
> +             ret = -ENOMEM;
> +             goto dbbt_page_err;
> +     }
> +
> +     dbbt = dbbt_page;
> +     dbbt->checksum = 0;
> +     dbbt->fingerprint = DBBT_FINGERPRINT2;
> +     dbbt->version = DBBT_VERSION_1;
> +     ret = dbbt_fill_data(mtd, dbbt_data_page, nr_blks);
> +     if (ret < 0)
> +             goto dbbt_data_page_err;
> +     else if (ret > 0)
> +             dbbt->dbbtpages = 1;
> +
> +     /* write fcb/dbbt */
> +     fcb_raw_page = kzalloc(mtd->writesize + mtd->oobsize, GFP_KERNEL);
> +     if (!fcb_raw_page) {
> +             debug("failed to allocate fcb_raw_page\n");
> +             ret = -ENOMEM;
> +             goto dbbt_data_page_err;
> +     }
> +
> +     memcpy(fcb_raw_page + 12, fcb, sizeof(struct fcb_block));
> +     encode_hamming_13_8(fcb_raw_page + 12, fcb_raw_page + 12 + 512, 512);
> +     /*
> +      * Set the first and second byte of OOB data to 0xFF, not 0x00. These
> +      * bytes are used as the Manufacturers Bad Block Marker (MBBM). Since
> +      * the FCB is mostly written to the first page in a block, a scan for
> +      * factory bad blocks will detect these blocks as bad, e.g. when
> +      * function nand_scan_bbt() is executed to build a new bad block table.
> +      */
> +     memset(fcb_raw_page + mtd->writesize, 0xFF, 2);
> +
> +     for (i = 0; i < nr_blks_fcb; i++) {
> +             if (mtd_block_isbad(mtd, off)) {
> +                     printf("Block %d is bad, skipped\n", i);
> +                     continue;
> +             }
> +
> +             /* raw write */
> +             mtd_oob_ops_t ops = {
> +                     .datbuf = (u8 *)fcb_raw_page,
> +                     .oobbuf = ((u8 *)fcb_raw_page) + mtd->writesize,
> +                     .len = mtd->writesize,
> +                     .ooblen = mtd->oobsize,
> +                     .mode = MTD_OPS_RAW
> +             };
> +
> +             ret = mtd_write_oob(mtd, mtd->erasesize * i, &ops);
> +             if (ret)
> +                     goto fcb_raw_page_err;
> +             debug("NAND fcb write: 0x%x offset, 0x%x bytes written: %s\n",
> +                   mtd->erasesize * i, ops.len, ret ? "ERROR" : "OK");
> +
> +             ret = mtd_write(mtd, mtd->erasesize * i + mtd->writesize,
> +                             mtd->writesize, &dummy, dbbt_page);
> +             if (ret)
> +                     goto fcb_raw_page_err;
> +             debug("NAND dbbt write: 0x%x offset, 0x%x bytes written: %s\n",
> +                   mtd->erasesize * i + mtd->writesize, dummy,
> +                   ret ? "ERROR" : "OK");
> +
> +             /* dbbtpages == 0 if no bad blocks */
> +             if (dbbt->dbbtpages > 0) {
> +                     loff_t to = (mtd->erasesize * i + mtd->writesize * 5);
> +
> +                     ret = mtd_write(mtd, to, mtd->writesize, &dummy,
> +                                     dbbt_data_page);
> +                     if (ret)
> +                             goto fcb_raw_page_err;
> +             }
> +     }
> +
> +fcb_raw_page_err:
> +     kfree(fcb_raw_page);
> +dbbt_data_page_err:
> +     kfree(dbbt_data_page);
> +dbbt_page_err:
> +     kfree(dbbt_page);
> +fcb_err:
> +     kfree(fcb);
> +fwbuf_err:
> +     kfree(fwbuf);
> +err:
> +     return ret;
> +}
> +
> +static int do_nandbcb_update(int argc, char * const argv[])
> +{
> +     struct mtd_info *mtd;
> +     loff_t addr, offset, size, maxsize;
> +     char *endp;
> +     u_char *buf;
> +     int dev;
> +     int ret;
> +
> +     if (argc != 4)
> +             return CMD_RET_USAGE;
> +
> +     dev = nand_curr_device;
> +     if (dev < 0) {
> +             printf("failed to get nand_curr_device, run nand device");
> +             return CMD_RET_FAILURE;
> +     }
> +
> +     addr = simple_strtoul(argv[1], &endp, 16);
> +     if (*argv[1] == 0 || *endp != 0)
> +             return CMD_RET_FAILURE;
> +
> +     mtd = get_nand_dev_by_index(dev);
> +     if (mtd_arg_off_size(argc - 2, argv + 2, &dev, &offset, &size,
> +                          &maxsize, MTD_DEV_TYPE_NAND, mtd->size))
> +             return CMD_RET_FAILURE;
> +
> +     buf = map_physmem(addr, size, MAP_WRBACK);
> +     if (!buf) {
> +             puts("failed to map physical memory\n");
> +             return CMD_RET_FAILURE;
> +     }
> +
> +     ret = nandbcb_update(mtd, offset, size, maxsize, buf);
> +
> +     return ret == 0 ? CMD_RET_SUCCESS : CMD_RET_FAILURE;
> +}
> +
> +static int do_nandbcb(cmd_tbl_t *cmdtp, int flag, int argc,
> +                   char * const argv[])
> +{
> +     const char *cmd;
> +     int ret = 0;
> +
> +     if (argc < 5)
> +             goto usage;
> +
> +     cmd = argv[1];
> +     --argc;
> +     ++argv;
> +
> +     if (strcmp(cmd, "update") == 0) {
> +             ret = do_nandbcb_update(argc, argv);
> +             goto done;
> +     }
> +
> +done:
> +     if (ret != -1)
> +             return ret;
> +usage:
> +     return CMD_RET_USAGE;
> +}
> +
> +static char nandbcb_help_text[] =
> +     "update addr off|partition len  - update 'len' bytes starting at\n"
> +     "       'off|part' to memory address 'addr', skipping  bad blocks";
> +
> +U_BOOT_CMD(nandbcb, 5, 1, do_nandbcb,
> +        "i.MX6 Nand BCB",
> +        nandbcb_help_text
> +);
> diff --git a/doc/imx/common/imx6.txt b/doc/imx/common/imx6.txt
> index eab88353f6..5a354005f8 100644
> --- a/doc/imx/common/imx6.txt
> +++ b/doc/imx/common/imx6.txt
> @@ -88,3 +88,78 @@ Reading bank 4:
>  
>  Word 0x00000002: 9f027772 00000004
>  
> +
> +NAND Boot on i.MX6 with SPL support
> +--------------------------------------
> +
> +Writing/updating boot image in nand device is not straight forward in
> +i.MX6 platform and it requires boot control block(BCB) to be configured.
> +
> +BCB contains two data structures, Firmware Configuration Block(FCB) and
> +Discovered Bad Block Table(DBBT). FCB has nand timings, DBBT search area,
> +and firmware. See IMX6DQRM Section 8.5.2.2
> +for more information.
> +
> +We can't use 'nand write' command to write SPL/firmware image directly
> +like other platforms does. So we need special setup to write BCB block
> +as per IMX6QDL reference manual 'nandbcb update' command do that job.
> +
> +for nand boot, up on reset bootrom look for FCB structure in
> +first block's if FCB found the nand timings are loaded for
> +further reads. once FCB read done, DTTB will be loaded and
> +finally firmware will be loaded which is boot image.
> +
> +cmd_nandbcb will create FCB these structures
> +by taking mtd partition as an example.
> +- initial code will erase entire partition
> +- followed by FCB setup, like first 2 blocks for FCB/DBBT write,
> +  and next block for FW1/SPL
> +- write firmware at FW1 block and
> +- finally write fcb/dttb in first 2 block.
> +
> +Typical NAND BCB layout:
> +=======================
> +
> +   no.of blocks = partition size / erasesize
> +   no.of fcb/dbbt blocks = 2
> +   FW1 offset = no.of fcb/dbbt
> +
> +block  0          1          2
> +        -------------------------------
> +       |FCB/DBBT 0|FCB/DBBT 1|  FW 1  |
> +       --------------------------------
> +
> +On summary, nandbcb update will
> +- erase the entire partition
> +- create BCB by creating 2 FCB/BDDT block followed by
> +  1 FW blocks based on partition size and erasesize.
> +- fill FCB/DBBT structures
> +- write FW/SPL in FW1
> +- write FCB/DBBT in first 2 blocks
> +
> +step-1: write SPL
> +
> +icorem6qdl> fatload mmc 0:1 $loadaddr SPL
> +reading SPL
> +31744 bytes read in 15 ms (2 MiB/s)
> +
> +icorem6qdl> nandbcb update $loadaddr spl $filesize
> +device 0 offset 0x0, size 0x7c00
> +Erasing at 0x1c0000 -- 100% complete.
> +NAND fw write: 0x100000 offset, 0x9000 bytes written: OK
> +NAND fw write: 0x180000 offset, 0x9000 bytes written: OK
> +
> +step-2: write u-boot-dtb.img
> +
> +icorem6qdl> nand erase.part uboot
> +NAND erase.part: device 0 offset 0x200000, size 0x200000
> +Erasing at 0x3c0000 -- 100% complete.
> +OK
> +
> +icorem6qdl> fatload mmc 0:1 $loadaddr u-boot-dtb.img
> +reading u-boot-dtb.img
> +508967 bytes read in 48 ms (10.1 MiB/s)
> +
> +icorem6qdl> nand write ${loadaddr} uboot ${filesize}
> +NAND write: device 0 offset 0x200000, size 0x7c427
> +508967 bytes written: OK
> diff --git a/drivers/mtd/nand/raw/mxs_nand.c b/drivers/mtd/nand/raw/mxs_nand.c
> index b93d77a395..91dcbc4d22 100644
> --- a/drivers/mtd/nand/raw/mxs_nand.c
> +++ b/drivers/mtd/nand/raw/mxs_nand.c
> @@ -25,7 +25,7 @@
>  #include <asm/mach-imx/regs-bch.h>
>  #include <asm/mach-imx/regs-gpmi.h>
>  #include <asm/arch/sys_proto.h>
> -#include "mxs_nand.h"
> +#include <asm/mach-imx/mxs-nand.h>
>  
>  #define      MXS_NAND_DMA_DESCRIPTOR_COUNT           4
>  
> diff --git a/drivers/mtd/nand/raw/mxs_nand_spl.c 
> b/drivers/mtd/nand/raw/mxs_nand_spl.c
> index ee7d9cb957..1f072721aa 100644
> --- a/drivers/mtd/nand/raw/mxs_nand_spl.c
> +++ b/drivers/mtd/nand/raw/mxs_nand_spl.c
> @@ -6,7 +6,8 @@
>  #include <common.h>
>  #include <nand.h>
>  #include <malloc.h>
> -#include "mxs_nand.h"
> +#include <asm/mach-imx/mxs-nand.h>
> +
>  
>  static struct mtd_info *mtd;
>  static struct nand_chip nand_chip;
> 

-- 
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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de
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