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    Subject[PATCH v3 05/16] mtd/docg3: fix reading oob+data without correction
    Date
    Fix the docg3 reads to be able to cope with all possible
    data buffer / oob buffer / file mode combinations from
    docg3_read_oob().
    This especially ensures that raw reads do not use ECC
    corrections, and AUTOOOB and PLACEOOB do use ECC
    correction.

    The approach is to empty docg3_read() and make it a wrapper
    to docg3_read_oob(). As docg3_read_oob() handles all the
    funny cases (no data buffer but oob buffer, data buffer but
    no oob buffer, ...), docg3_read() is just a special use of
    docg3_read_oob().

    Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
    ---
    drivers/mtd/devices/docg3.c | 194 +++++++++++++++++++++----------------------
    1 files changed, 95 insertions(+), 99 deletions(-)

    diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
    index 5834e6e..1c2f54d 100644
    --- a/drivers/mtd/devices/docg3.c
    +++ b/drivers/mtd/devices/docg3.c
    @@ -196,8 +196,8 @@ static int doc_reset_seq(struct docg3 *docg3)
    /**
    * doc_read_data_area - Read data from data area
    * @docg3: the device
    - * @buf: the buffer to fill in
    - * @len: the lenght to read
    + * @buf: the buffer to fill in (might be NULL is dummy reads)
    + * @len: the length to read
    * @first: first time read, DOC_READADDRESS should be set
    *
    * Reads bytes from flash data. Handles the single byte / even bytes reads.
    @@ -218,8 +218,10 @@ static void doc_read_data_area(struct docg3 *docg3, void *buf, int len,
    dst16 = buf;
    for (i = 0; i < len4; i += 2) {
    data16 = doc_readw(docg3, DOC_IOSPACE_DATA);
    - *dst16 = data16;
    - dst16++;
    + if (dst16) {
    + *dst16 = data16;
    + dst16++;
    + }
    }

    if (cdr) {
    @@ -229,8 +231,10 @@ static void doc_read_data_area(struct docg3 *docg3, void *buf, int len,
    dst8 = (u8 *)dst16;
    for (i = 0; i < cdr; i++) {
    data8 = doc_readb(docg3, DOC_IOSPACE_DATA);
    - *dst8 = data8;
    - dst8++;
    + if (dst8) {
    + *dst8 = data8;
    + dst8++;
    + }
    }
    }
    }
    @@ -542,96 +546,109 @@ static void calc_block_sector(loff_t from, int *block0, int *block1, int *page,
    }

    /**
    - * doc_read - Read bytes from flash
    + * doc_read_oob - Read out of band bytes from flash
    * @mtd: the device
    * @from: the offset from first block and first page, in bytes, aligned on page
    * size
    - * @len: the number of bytes to read (must be a multiple of 4)
    - * @retlen: the number of bytes actually read
    - * @buf: the filled in buffer
    + * @ops: the mtd oob structure
    *
    - * Reads flash memory pages. This function does not read the OOB chunk, but only
    - * the page data.
    + * Reads flash memory OOB area of pages.
    *
    * Returns 0 if read successfull, of -EIO, -EINVAL if an error occured
    */
    -static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
    - size_t *retlen, u_char *buf)
    +static int doc_read_oob(struct mtd_info *mtd, loff_t from,
    + struct mtd_oob_ops *ops)
    {
    struct docg3 *docg3 = mtd->priv;
    - int block0, block1, page, readlen, ret, ofs = 0;
    - int syn[DOC_ECC_BCH_SIZE], eccconf1;
    - u8 oob[DOC_LAYOUT_OOB_SIZE];
    + int block0, block1, page, ret, ofs = 0;
    + u8 *oobbuf = ops->oobbuf;
    + u8 *buf = ops->datbuf;
    + size_t len, ooblen, nbdata, nboob;
    + u8 calc_ecc[DOC_ECC_BCH_SIZE], eccconf1;
    +
    + if (buf)
    + len = ops->len;
    + else
    + len = 0;
    + if (oobbuf)
    + ooblen = ops->ooblen;
    + else
    + ooblen = 0;
    +
    + if (oobbuf && ops->mode == MTD_OPS_PLACE_OOB)
    + oobbuf += ops->ooboffs;
    +
    + doc_dbg("doc_read_oob(from=%lld, mode=%d, data=(%p:%zu), oob=(%p:%zu))\n",
    + from, ops->mode, buf, len, oobbuf, ooblen);
    + if ((len % DOC_LAYOUT_PAGE_SIZE) || (ooblen % DOC_LAYOUT_OOB_SIZE) ||
    + (from % DOC_LAYOUT_PAGE_SIZE))
    + return -EINVAL;

    ret = -EINVAL;
    - doc_dbg("doc_read(from=%lld, len=%zu, buf=%p)\n", from, len, buf);
    - if (from % DOC_LAYOUT_PAGE_SIZE)
    - goto err;
    - if (len % 4)
    - goto err;
    - calc_block_sector(from, &block0, &block1, &page, &ofs);
    + calc_block_sector(from + len, &block0, &block1, &page, &ofs);
    if (block1 > docg3->max_block)
    goto err;

    - *retlen = 0;
    + ops->oobretlen = 0;
    + ops->retlen = 0;
    ret = 0;
    - readlen = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
    - while (!ret && len > 0) {
    - readlen = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
    + while (!ret && (len > 0 || ooblen > 0)) {
    + calc_block_sector(from, &block0, &block1, &page, &ofs);
    + nbdata = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
    + nboob = min_t(size_t, ooblen, (size_t)DOC_LAYOUT_OOB_SIZE);
    ret = doc_read_page_prepare(docg3, block0, block1, page, ofs);
    if (ret < 0)
    goto err;
    ret = doc_read_page_ecc_init(docg3, DOC_ECC_BCH_COVERED_BYTES);
    if (ret < 0)
    goto err_in_read;
    - ret = doc_read_page_getbytes(docg3, readlen, buf, 1);
    - if (ret < readlen)
    + ret = doc_read_page_getbytes(docg3, nbdata, buf, 1);
    + if (ret < nbdata)
    goto err_in_read;
    - ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE,
    - oob, 0);
    - if (ret < DOC_LAYOUT_OOB_SIZE)
    + doc_read_page_getbytes(docg3, DOC_LAYOUT_PAGE_SIZE - nbdata,
    + NULL, 0);
    + ret = doc_read_page_getbytes(docg3, nboob, oobbuf, 0);
    + if (ret < nboob)
    goto err_in_read;
    + doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE - nboob,
    + NULL, 0);

    - *retlen += readlen;
    - buf += readlen;
    - len -= readlen;
    -
    - ofs ^= DOC_LAYOUT_PAGE_OOB_SIZE;
    - if (ofs == 0)
    - page += 2;
    - if (page > DOC_ADDR_PAGE_MASK) {
    - page = 0;
    - block0 += 2;
    - block1 += 2;
    - }
    -
    - /*
    - * There should be a BCH bitstream fixing algorithm here ...
    - * By now, a page read failure is triggered by BCH error
    - */
    - doc_get_hw_bch_syndroms(docg3, syn);
    + doc_get_hw_bch_syndroms(docg3, calc_ecc);
    eccconf1 = doc_register_readb(docg3, DOC_ECCCONF1);

    - doc_dbg("OOB - INFO: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    - oob[0], oob[1], oob[2], oob[3], oob[4],
    - oob[5], oob[6]);
    - doc_dbg("OOB - HAMMING: %02x\n", oob[7]);
    - doc_dbg("OOB - BCH_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    - oob[8], oob[9], oob[10], oob[11], oob[12],
    - oob[13], oob[14]);
    - doc_dbg("OOB - UNUSED: %02x\n", oob[15]);
    + if (nboob >= DOC_LAYOUT_OOB_SIZE) {
    + doc_dbg("OOB - INFO: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    + oobbuf[0], oobbuf[1], oobbuf[2], oobbuf[3],
    + oobbuf[4], oobbuf[5], oobbuf[6]);
    + doc_dbg("OOB - HAMMING: %02x\n", oobbuf[7]);
    + doc_dbg("OOB - BCH_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    + oobbuf[8], oobbuf[9], oobbuf[10], oobbuf[11],
    + oobbuf[12], oobbuf[13], oobbuf[14]);
    + doc_dbg("OOB - UNUSED: %02x\n", oobbuf[15]);
    + }
    doc_dbg("ECC checks: ECCConf1=%x\n", eccconf1);
    - doc_dbg("ECC BCH syndrom: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    - syn[0], syn[1], syn[2], syn[3], syn[4], syn[5], syn[6]);
    + doc_dbg("ECC CALC_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
    + calc_ecc[0], calc_ecc[1], calc_ecc[2],
    + calc_ecc[3], calc_ecc[4], calc_ecc[5],
    + calc_ecc[6]);

    ret = -EBADMSG;
    if (block0 >= DOC_LAYOUT_BLOCK_FIRST_DATA) {
    - if (eccconf1 & DOC_ECCCONF1_BCH_SYNDROM_ERR)
    + if ((eccconf1 & DOC_ECCCONF1_BCH_SYNDROM_ERR) &&
    + (eccconf1 & DOC_ECCCONF1_PAGE_IS_WRITTEN))
    goto err_in_read;
    if (is_prot_seq_error(docg3))
    goto err_in_read;
    }
    +
    doc_read_page_finish(docg3);
    + ops->retlen += nbdata;
    + ops->oobretlen += nboob;
    + buf += nbdata;
    + oobbuf += nboob;
    + len -= nbdata;
    + ooblen -= nboob;
    + from += DOC_LAYOUT_PAGE_SIZE;
    }

    return 0;
    @@ -642,54 +659,33 @@ err:
    }

    /**
    - * doc_read_oob - Read out of band bytes from flash
    + * doc_read - Read bytes from flash
    * @mtd: the device
    * @from: the offset from first block and first page, in bytes, aligned on page
    * size
    - * @ops: the mtd oob structure
    + * @len: the number of bytes to read (must be a multiple of 4)
    + * @retlen: the number of bytes actually read
    + * @buf: the filled in buffer
    *
    - * Reads flash memory OOB area of pages.
    + * Reads flash memory pages. This function does not read the OOB chunk, but only
    + * the page data.
    *
    * Returns 0 if read successfull, of -EIO, -EINVAL if an error occured
    */
    -static int doc_read_oob(struct mtd_info *mtd, loff_t from,
    - struct mtd_oob_ops *ops)
    +static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
    + size_t *retlen, u_char *buf)
    {
    - struct docg3 *docg3 = mtd->priv;
    - int block0, block1, page, ofs, ret;
    - u8 *buf = ops->oobbuf;
    - size_t len = ops->ooblen;
    + struct mtd_oob_ops ops;
    + size_t ret;

    - doc_dbg("doc_read_oob(from=%lld, buf=%p, len=%zu)\n", from, buf, len);
    - if (len != DOC_LAYOUT_OOB_SIZE)
    - return -EINVAL;
    + memset(&ops, 0, sizeof(ops));
    + ops.datbuf = buf;
    + ops.len = len;
    + ops.mode = MTD_OPS_AUTO_OOB;

    - switch (ops->mode) {
    - case MTD_OPS_PLACE_OOB:
    - buf += ops->ooboffs;
    - break;
    - default:
    - break;
    - }
    -
    - calc_block_sector(from, &block0, &block1, &page, &ofs);
    - if (block1 > docg3->max_block)
    - return -EINVAL;
    -
    - ret = doc_read_page_prepare(docg3, block0, block1, page,
    - ofs + DOC_LAYOUT_PAGE_SIZE);
    - if (!ret)
    - ret = doc_read_page_ecc_init(docg3, DOC_LAYOUT_OOB_SIZE);
    - if (!ret)
    - ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE,
    - buf, 1);
    - doc_read_page_finish(docg3);
    -
    - if (ret > 0)
    - ops->oobretlen = ret;
    - else
    - ops->oobretlen = 0;
    - return (ret > 0) ? 0 : ret;
    + ret = doc_read_oob(mtd, from, &ops);
    + *retlen = ops.retlen;
    + return ret;
    }

    static int doc_reload_bbt(struct docg3 *docg3)
    --
    1.7.5.4


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