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Subject[RFC 42/47] mtd: nand: stm_nand_bch: add read and write OOB (BCH)
Date
Provide functions to read and write to the Out-Of-Bounds (OOB) area.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/mtd/nand/stm_nand_bch.c | 107 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 107 insertions(+)

diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c
index 38658b8..389ccee 100644
--- a/drivers/mtd/nand/stm_nand_bch.c
+++ b/drivers/mtd/nand/stm_nand_bch.c
@@ -1218,6 +1218,111 @@ static int flex_do_write_ops(struct nandi_controller *nandi,
return 0;
}

+static char *mtd_oob_mode_strs[] = {"PLACE", "AUTO", "RAW"};
+
+static int bch_mtd_read_and_write_oob(struct mtd_info *mtd, loff_t tofrom,
+ struct mtd_oob_ops *ops,
+ bool read)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct nandi_controller *nandi = chip->priv;
+ uint32_t page_mask = mtd->writesize - 1;
+ int ret;
+
+ dev_dbg(nandi->dev, "%s: 0x%012llx [page = %u, oob = %u mode = %s]\n",
+ __func__, tofrom,
+ (ops->datbuf ? ops->len : 0),
+ (ops->oobbuf ? ops->ooblen : 0),
+ mtd_oob_mode_strs[ops->mode]);
+
+ if (!ops->oobbuf && ops->mode != MTD_OPS_RAW) {
+ if (read)
+ return mtd_read(mtd, tofrom, ops->len,
+ &ops->retlen, ops->datbuf);
+ else
+ return mtd_write(mtd, tofrom, ops->len,
+ &ops->retlen, ops->datbuf);
+ }
+
+ ops->oobretlen = 0;
+ ops->retlen = 0;
+
+ /*
+ * We report OOB as unavailable (i.e. oobavail = 0), therefore nothing
+ * should call this
+ */
+ if (ops->oobbuf && ops->mode == MTD_OPS_AUTO_OOB)
+ return -ENOTSUPP;
+
+ /* Not currently supported by MTD */
+ if (ops->datbuf && ops->oobbuf && ops->mode == MTD_OPS_PLACE_OOB)
+ return -ENOTSUPP;
+
+ /* Do not allow oob reads with ooboffs */
+ if (ops->oobbuf && ops->ooboffs)
+ return -ENOTSUPP;
+
+ /* Do not allow reads past end of device */
+ if (ops->datbuf && (tofrom + ops->len) > mtd->size) {
+ dev_err(nandi->dev, "attempt %s beyond end of device\n",
+ read ? "read" : "write");
+ return -EINVAL;
+ }
+
+ if (ops->oobbuf &&
+ (tofrom + mtd->writesize * (ops->ooblen / mtd->oobsize))
+ > mtd->size) {
+ dev_err(nandi->dev, "attempt %s beyond end of device\n",
+ read ? "read" : "write");
+ return -EINVAL;
+ }
+
+ /* Do not allow non-aligned reads/writes */
+ if ((tofrom & page_mask) ||
+ (ops->datbuf && (ops->len & page_mask)) ||
+ (ops->oobbuf && (ops->ooblen % mtd->oobsize))) {
+ dev_err(nandi->dev, "attempt to %s non-aligned data\n",
+ read ? "read" : "write");
+ return -EINVAL;
+ }
+
+ /* Do not allow inconsistent data and oob lengths */
+ if (ops->datbuf && ops->oobbuf &&
+ (ops->len / mtd->writesize != ops->ooblen / mtd->oobsize)) {
+ dev_err(nandi->dev,
+ "data length inconsistent with oob length\n");
+ return -EINVAL;
+ }
+
+ nand_get_device(mtd, read ? FL_READING : FL_WRITING);
+
+ if (!read && flex_check_wp(nandi)) {
+ dev_dbg(nandi->dev, "device is write-protected\n");
+ return -EIO;
+ }
+
+ if (read)
+ ret = flex_do_read_ops(nandi, tofrom, ops);
+ else
+ ret = flex_do_write_ops(nandi, tofrom, ops);
+
+ nand_release_device(mtd);
+
+ return ret;
+}
+
+static int bch_mtd_read_oob(struct mtd_info *mtd, loff_t from,
+ struct mtd_oob_ops *ops)
+{
+ return bch_mtd_read_and_write_oob(mtd, from, ops, true);
+}
+
+static int bch_mtd_write_oob(struct mtd_info *mtd, loff_t to,
+ struct mtd_oob_ops *ops)
+{
+ return bch_mtd_read_and_write_oob(mtd, to, ops, false);
+}
+
static int bch_mtd_block_isbad(struct mtd_info *mtd, loff_t offs)
{
struct nand_chip *chip = mtd->priv;
@@ -1454,6 +1559,8 @@ static void nandi_set_mtd_defaults(struct nandi_controller *nandi,
mtd->subpage_sft = 0;

mtd->_erase = bch_mtd_erase;
+ mtd->_read_oob = bch_mtd_read_oob;
+ mtd->_write_oob = bch_mtd_write_oob;
mtd->_block_isbad = bch_mtd_block_isbad;
mtd->_block_markbad = bch_mtd_block_markbad;

--
1.8.3.2


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