From: "Wan, Jane (Nokia - US/Sunnyvale)" <jane.wan@nokia.com>
To: "Boris.Brezillon@bootlin.com" <Boris.Brezillon@bootlin.com>,
"miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
"dwmw2@infradead.org" <dwmw2@infradead.org>,
"computersforpeace@gmail.com" <computersforpeace@gmail.com>,
"richard@nod.at" <richard@nod.at>,
"marek.vasut@gmail.com" <marek.vasut@gmail.com>,
"yamada.masahiro@socionext.com" <yamada.masahiro@socionext.com>,
"prabhakar.kushwaha@nxp.com" <prabhakar.kushwaha@nxp.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"jagdish.gediya@nxp.com" <jagdish.gediya@nxp.com>,
"shreeya.patel23498@gmail.com" <shreeya.patel23498@gmail.com>
Cc: "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Bos, Ties (Nokia - US/Sunnyvale)" <ties.bos@nokia.com>,
"Wan, Jane (Nokia - US/Sunnyvale)" <jane.wan@nokia.com>
Subject: [PATCH v7] mtd: rawnand: use bit-wise majority to recover the contents of ONFI parameter
Date: Sun, 13 May 2018 04:30:02 +0000 [thread overview]
Message-ID: <VI1PR07MB1615A02B23D992E84A3B333F819D0@VI1PR07MB1615.eurprd07.prod.outlook.com> (raw)
Per ONFI specification (Rev. 4.0), if all parameter pages have invalid CRC values, the bit-wise majority may be used to recover the contents of the parameter pages from the parameter page copies present.
Signed-off-by: Jane Wan <Jane.Wan@nokia.com>
---
v7: change debug print messages
v6: support the cases that srcbufs are not contiguous
v5: make the bit-wise majority functon generic
v4: move the bit-wise majority code in a separate function
v3: fix warning message detected by kbuild test robot
v2: rebase the changes on top of v4.17-rc1
drivers/mtd/nand/raw/nand_base.c | 50 ++++++++++++++++++++++++++++++++++----
1 file changed, 45 insertions(+), 5 deletions(-)
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 72f3a89..b43b784 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -5087,6 +5087,35 @@ static int nand_flash_detect_ext_param_page(struct nand_chip *chip,
}
/*
+ * Recover data with bit-wise majority
+ */
+static void nand_bit_wise_majority(const void **srcbufs,
+ unsigned int nsrcbufs,
+ void *dstbuf,
+ unsigned int bufsize)
+{
+ int i, j, k;
+
+ for (i = 0; i < bufsize; i++) {
+ u8 cnt, val;
+
+ val = 0;
+ for (j = 0; j < 8; j++) {
+ cnt = 0;
+ for (k = 0; k < nsrcbufs; k++) {
+ const u8 *srcbuf = srcbufs[k];
+
+ if (srcbuf[i] & BIT(j))
+ cnt++;
+ }
+ if (cnt > nsrcbufs / 2)
+ val |= BIT(j);
+ }
+ ((u8 *)dstbuf)[i] = val;
+ }
+}
+
+/*
* Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
*/
static int nand_flash_detect_onfi(struct nand_chip *chip)
@@ -5102,7 +5131,7 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
return 0;
/* ONFI chip: allocate a buffer to hold its parameter page */
- p = kzalloc(sizeof(*p), GFP_KERNEL);
+ p = kzalloc((sizeof(*p) * 3), GFP_KERNEL);
if (!p)
return -ENOMEM;
@@ -5113,21 +5142,32 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
}
for (i = 0; i < 3; i++) {
- ret = nand_read_data_op(chip, p, sizeof(*p), true);
+ ret = nand_read_data_op(chip, &p[i], sizeof(*p), true);
if (ret) {
ret = 0;
goto free_onfi_param_page;
}
- if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) ==
+ if (onfi_crc16(ONFI_CRC_BASE, (u8 *)&p[i], 254) ==
le16_to_cpu(p->crc)) {
+ if (i)
+ memcpy(p, &p[i], sizeof(*p));
break;
}
}
if (i == 3) {
- pr_err("Could not find valid ONFI parameter page; aborting\n");
- goto free_onfi_param_page;
+ const void *srcbufs[3] = {p, p + 1, p + 2};
+
+ pr_warn("Could not find a valid ONFI parameter page, trying bit-wise majority to recover it\n");
+ nand_bit_wise_majority(srcbufs, ARRAY_SIZE(srcbufs), p,
+ sizeof(*p));
+
+ if (onfi_crc16(ONFI_CRC_BASE, (u8 *)p, 254) !=
+ le16_to_cpu(p->crc)) {
+ pr_err("ONFI parameter recovery failed, aborting\n");
+ goto free_onfi_param_page;
+ }
}
/* Check version */
--
1.7.9.5
next reply other threads:[~2018-05-13 4:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-13 4:30 Wan, Jane (Nokia - US/Sunnyvale) [this message]
2018-05-13 9:49 ` [PATCH v7] mtd: rawnand: use bit-wise majority to recover the contents of ONFI parameter Boris Brezillon
2018-05-15 4:45 ` Chris Moore
2018-05-15 7:34 ` Boris Brezillon
2018-05-16 7:32 ` Chris Moore
2018-05-16 7:42 ` Miquel Raynal
2018-05-16 9:08 ` Boris Brezillon
2018-05-16 7:56 ` Boris Brezillon
2018-05-17 4:28 ` Chris Moore
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=VI1PR07MB1615A02B23D992E84A3B333F819D0@VI1PR07MB1615.eurprd07.prod.outlook.com \
--to=jane.wan@nokia.com \
--cc=Boris.Brezillon@bootlin.com \
--cc=computersforpeace@gmail.com \
--cc=dwmw2@infradead.org \
--cc=jagdish.gediya@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=marek.vasut@gmail.com \
--cc=miquel.raynal@bootlin.com \
--cc=prabhakar.kushwaha@nxp.com \
--cc=richard@nod.at \
--cc=shawnguo@kernel.org \
--cc=shreeya.patel23498@gmail.com \
--cc=ties.bos@nokia.com \
--cc=yamada.masahiro@socionext.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).