lkml.org 
[lkml]   [2017]   [Sep]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH -next v2] mtd: nand: Add support for Toshiba BENAND (Built-in ECC NAND)
Date
This patch enables support for Toshiba BENAND.
The current implementation does not support vondor specific command
TOSHIBA_NAND_CMD_ECC_STATUS. I would like to add the command, when
the exec_op() [1] infrastructure is implemented.

[1] https://github.com/bbrezillon/linux/commits/nand/exec_op1

Changelog[v2]:
Rewrite to adapt the mtd "separate vendor specific code from
core" cleanup process that based on comments from the following
discussion.
http://patchwork.ozlabs.org/patch/767191/

Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
---
drivers/mtd/nand/nand_toshiba.c | 100 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 100 insertions(+)

diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
index 57df857..7a99bbe 100644
--- a/drivers/mtd/nand/nand_toshiba.c
+++ b/drivers/mtd/nand/nand_toshiba.c
@@ -17,6 +17,72 @@

#include <linux/mtd/rawnand.h>

+/* ECC Status Read Command for BENAND */
+#define TOSHIBA_NAND_CMD_ECC_STATUS 0x7A
+
+/* Recommended to rewrite for BENAND */
+#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED BIT(3)
+
+static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
+ struct nand_chip *chip)
+{
+ unsigned int max_bitflips = 0;
+ u8 status;
+
+ /* Check Read Status */
+ chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
+ status = chip->read_byte(mtd);
+
+ /*
+ * TOSHIBA_NAND_CMD_ECC_STATUS is vendor specific command.
+ * We will rewrite this code, after the ->exec_op() infrastructure
+ * is implemented
+ * Now, we set max_bitflips mtd->bitflip_threshold.
+ */
+ if (status & NAND_STATUS_FAIL) {
+ /* uncorrectable */
+ mtd->ecc_stats.failed++;
+ } else if (status & TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED) {
+ /* correctable */
+ max_bitflips = mtd->bitflip_threshold;
+ mtd->ecc_stats.corrected += max_bitflips;
+ }
+
+ return max_bitflips;
+}
+
+static int
+toshiba_nand_read_page_benand(struct mtd_info *mtd,
+ struct nand_chip *chip, uint8_t *buf,
+ int oob_required, int page)
+{
+ unsigned int max_bitflips = 0;
+
+ chip->ecc.read_page_raw(mtd, chip, buf, oob_required, page);
+ max_bitflips = toshiba_nand_benand_status_chk(mtd, chip);
+
+ return max_bitflips;
+}
+
+static int
+toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
+ struct nand_chip *chip, uint32_t data_offs,
+ uint32_t readlen, uint8_t *bufpoi, int page)
+{
+ uint8_t *p;
+ unsigned int max_bitflips = 0;
+
+ if (data_offs != 0)
+ chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
+
+ p = bufpoi + data_offs;
+ chip->read_buf(mtd, p, readlen);
+
+ max_bitflips = toshiba_nand_benand_status_chk(mtd, chip);
+
+ return max_bitflips;
+}
+
static void toshiba_nand_decode_id(struct nand_chip *chip)
{
struct mtd_info *mtd = nand_to_mtd(chip);
@@ -39,9 +105,43 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)

static int toshiba_nand_init(struct nand_chip *chip)
{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+
if (nand_is_slc(chip))
chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;

+ if (nand_is_slc(chip) && (chip->id.data[4] & 0x80)) {
+ /* BENAND */
+
+ /*
+ * We can't disable the internal ECC engine, the user
+ * has to use on-die ECC, there is no alternative.
+ */
+ if (chip->ecc.mode != NAND_ECC_ON_DIE) {
+ pr_err("On-die ECC should be selected.\n");
+ return -EINVAL;
+ }
+
+ /*
+ * On BENAND, all OOB reginon can be used by user (driver).
+ * The calculated ECC bytes are stored into other isolated
+ * area which is ubable to access from user.
+ * This is why chip->ecc.bytes = 0.
+ */
+ chip->ecc.bytes = 0;
+ chip->ecc.size = 512;
+ chip->ecc.strength = 8;
+ chip->ecc.read_page = toshiba_nand_read_page_benand;
+ chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
+ chip->ecc.write_page = nand_write_page_raw;
+ chip->ecc.read_page_raw = nand_read_page_raw;
+ chip->ecc.write_page_raw = nand_write_page_raw;
+
+ chip->options |= NAND_SUBPAGE_READ;
+
+ mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+ }
+
return 0;
}

--
2.7.4

\
 
 \ /
  Last update: 2017-09-21 19:27    [W:0.060 / U:0.760 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site