Patchwork [V4,4/9] mtd: get the ECC info from the Extended Parameter Page

login
register
mail settings
Submitter Huang Shijie
Date April 26, 2013, 9:08 a.m.
Message ID <1366967337-5534-5-git-send-email-b32955@freescale.com>
Download mbox | patch
Permalink /patch/239782/
State New
Headers show

Comments

Huang Shijie - April 26, 2013, 9:08 a.m.
Since the ONFI 2.1, the onfi spec adds the Extended Parameter Page
to store the ECC info.

The onfi spec tells us that if the nand chip's recommended ECC codeword
size is not 512 bytes, then the @ecc_bits is 0xff. The host _SHOULD_ then
read the Extended ECC information that is part of the extended parameter
page to retrieve the ECC requirements for this device.

This patch implement the reading of the Extended Parameter Page, and parses
the sections for ECC type, and get the ECC info from the ECC section.

Tested this patch with Micron MT29F64G08CBABAWP.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 drivers/mtd/nand/nand_base.c |   77 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 77 insertions(+), 0 deletions(-)
pekon gupta - May 2, 2013, 7:43 a.m.
> Since the ONFI 2.1, the onfi spec adds the Extended Parameter Page
> to store the ECC info.
> 
> The onfi spec tells us that if the nand chip's recommended ECC codeword
> size is not 512 bytes, then the @ecc_bits is 0xff. The host _SHOULD_
> then
> read the Extended ECC information that is part of the extended
> parameter
> page to retrieve the ECC requirements for this device.
> 
> This patch implement the reading of the Extended Parameter Page, and
> parses
> the sections for ECC type, and get the ECC info from the ECC section.
> 
> Tested this patch with Micron MT29F64G08CBABAWP.
> 
> Signed-off-by: Huang Shijie <b32955@freescale.com>

Acked-by: Pekon Gupta <pekon@ti.com>

Thanks..
with regards, pekon
Brian Norris - May 2, 2013, 11:39 p.m.
Hi Huang,

On Fri, Apr 26, 2013 at 2:08 AM, Huang Shijie <b32955@freescale.com> wrote:
> Since the ONFI 2.1, the onfi spec adds the Extended Parameter Page
> to store the ECC info.
>
> The onfi spec tells us that if the nand chip's recommended ECC codeword
> size is not 512 bytes, then the @ecc_bits is 0xff. The host _SHOULD_ then
> read the Extended ECC information that is part of the extended parameter
> page to retrieve the ECC requirements for this device.
>
> This patch implement the reading of the Extended Parameter Page, and parses
> the sections for ECC type, and get the ECC info from the ECC section.
>
> Tested this patch with Micron MT29F64G08CBABAWP.
>
> Signed-off-by: Huang Shijie <b32955@freescale.com>
> ---
>  drivers/mtd/nand/nand_base.c |   77 ++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 77 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index beff911..abec615 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -2846,6 +2846,68 @@ static u16 onfi_crc16(u16 crc, u8 const *p, size_t len)
>         return crc;
>  }
>
> +/* Parse the Extended Parameter Page. */
> +static int nand_flash_detect_ext_param_page(struct mtd_info *mtd,
> +               struct nand_chip *chip, struct nand_onfi_params *p)
> +{
> +       struct onfi_ext_param_page *ep;
> +       struct onfi_ext_section *s;
> +       struct onfi_ext_ecc_info *ecc;
> +       uint8_t *cursor;
> +       int len;
> +       int ret;
> +       int i;
> +
> +       len = le16_to_cpu(p->ext_param_page_length) * 16;
> +       ep = kmalloc(len, GFP_KERNEL);
> +       if (!ep) {
> +               ret = -ENOMEM;
> +               goto ext_out;
> +       }
> +
> +       /* Send our own NAND_CMD_PARAM. */
> +       chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
> +
> +       /* Use the Change Read Column command to skip the ONFI param pages. */
> +       chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
> +                       sizeof(*p) * p->num_of_param_pages , -1);
> +
> +       /* Read out the Extended Parameter Page. */
> +       chip->read_buf(mtd, (uint8_t *)ep, len);
> +       if ((onfi_crc16(ONFI_CRC_BASE, ((uint8_t *)ep) + 2, len - 2)
> +               != le16_to_cpu(ep->crc)) || strncmp(ep->sig, "EPPS", 4)) {
> +               pr_debug("fail in the CRC.\n");
> +               ret = -EINVAL;
> +               goto ext_out;
> +       }
> +
> +       /* find the ECC section. */
> +       cursor = (uint8_t *)(ep + 1);
> +       for (i = 0; i < ONFI_EXT_SECTION_MAX; i++) {
> +               s = ep->sections + i;
> +               if (s->type == ONFI_SECTION_TYPE_2)
> +                       break;
> +               cursor += s->length * 16;
> +       }
> +       if (i == ONFI_EXT_SECTION_MAX) {
> +               pr_debug("We can not find the ECC section.\n");
> +               ret = -EINVAL;
> +               goto ext_out;
> +       }
> +
> +       /* get the info we want. */
> +       ecc = (struct onfi_ext_ecc_info *)cursor;
> +       chip->ecc_strength = ecc->ecc_bits;
> +       chip->ecc_size = 1 << ecc->codeword_size;
> +
> +       pr_info("ONFI extended param page detected.\n");
> +       return 0;
> +
> +ext_out:
> +       kfree(ep);
> +       return ret;
> +}
> +
>  /*
>   * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
>   */
> @@ -2914,6 +2976,21 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
>         if (p->ecc_bits != 0xff) {
>                 chip->ecc_strength = p->ecc_bits;
>                 chip->ecc_size = 512;
> +       } else if (chip->onfi_version >= 21 &&
> +               (onfi_feature(chip) & ONFI_FEATURE_EXT_PARAM_PAGE)) {
> +
> +               /*
> +                * The nand_flash_detect_ext_param_page() uses the
> +                * Change Read Column command which maybe not supported
> +                * by the chip->cmdfunc. So try to update the chip->cmdfunc
> +                * now. We do not replace user supplied command function.
> +                */
> +               if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
> +                       chip->cmdfunc = nand_command_lp;

I don't think we want to assign chip->cmdfunc within the 'detect_onfi'
function. We already have several places from which the default
functions may be assigned. Rather, we should only code the above
statement *once* (where it already is, in nand_get_flash_type()) and
only run the extended parameter page function after that point.

If that's too cumbersome, then maybe it's fine as-is. Or I'll take a
crack at rewriting it myself.

> +               /* The Extended Parameter Page is supported since ONFI 2.1. */
> +               if (nand_flash_detect_ext_param_page(mtd, chip, p))
> +                       pr_info("Failed to detect the extended param page.\n");
>         }
>
>         pr_info("ONFI flash detected\n");
> --
> 1.7.1
>
>

Brian
Huang Shijie - May 3, 2013, 2:52 a.m.
于 2013年05月03日 07:39, Brian Norris 写道:
> only run the extended parameter page function after that point.
sorry, I prefer to run the extended parameter page function here just 
following the case
"p-> ecc_bits != 0xff". IMHO, the two cases should be put together as 
the onfi spec tells, rather be split out
far away. The extended parameter page function is just the case 
"p->ecc_bits == 0xff".

If we put the nand_flash_detect_ext_param_page() after the point we 
reassign the chip->cmdfunc,
It's a little discrete in logic which makes the code not compact enough.

btw: Could you check you email client? I failed several times for the 
HTML issue.

thanks
Huang Shijie

Patch

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index beff911..abec615 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2846,6 +2846,68 @@  static u16 onfi_crc16(u16 crc, u8 const *p, size_t len)
 	return crc;
 }
 
+/* Parse the Extended Parameter Page. */
+static int nand_flash_detect_ext_param_page(struct mtd_info *mtd,
+		struct nand_chip *chip, struct nand_onfi_params *p)
+{
+	struct onfi_ext_param_page *ep;
+	struct onfi_ext_section *s;
+	struct onfi_ext_ecc_info *ecc;
+	uint8_t *cursor;
+	int len;
+	int ret;
+	int i;
+
+	len = le16_to_cpu(p->ext_param_page_length) * 16;
+	ep = kmalloc(len, GFP_KERNEL);
+	if (!ep) {
+		ret = -ENOMEM;
+		goto ext_out;
+	}
+
+	/* Send our own NAND_CMD_PARAM. */
+	chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
+
+	/* Use the Change Read Column command to skip the ONFI param pages. */
+	chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
+			sizeof(*p) * p->num_of_param_pages , -1);
+
+	/* Read out the Extended Parameter Page. */
+	chip->read_buf(mtd, (uint8_t *)ep, len);
+	if ((onfi_crc16(ONFI_CRC_BASE, ((uint8_t *)ep) + 2, len - 2)
+		!= le16_to_cpu(ep->crc)) || strncmp(ep->sig, "EPPS", 4)) {
+		pr_debug("fail in the CRC.\n");
+		ret = -EINVAL;
+		goto ext_out;
+	}
+
+	/* find the ECC section. */
+	cursor = (uint8_t *)(ep + 1);
+	for (i = 0; i < ONFI_EXT_SECTION_MAX; i++) {
+		s = ep->sections + i;
+		if (s->type == ONFI_SECTION_TYPE_2)
+			break;
+		cursor += s->length * 16;
+	}
+	if (i == ONFI_EXT_SECTION_MAX) {
+		pr_debug("We can not find the ECC section.\n");
+		ret = -EINVAL;
+		goto ext_out;
+	}
+
+	/* get the info we want. */
+	ecc = (struct onfi_ext_ecc_info *)cursor;
+	chip->ecc_strength = ecc->ecc_bits;
+	chip->ecc_size = 1 << ecc->codeword_size;
+
+	pr_info("ONFI extended param page detected.\n");
+	return 0;
+
+ext_out:
+	kfree(ep);
+	return ret;
+}
+
 /*
  * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
  */
@@ -2914,6 +2976,21 @@  static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 	if (p->ecc_bits != 0xff) {
 		chip->ecc_strength = p->ecc_bits;
 		chip->ecc_size = 512;
+	} else if (chip->onfi_version >= 21 &&
+		(onfi_feature(chip) & ONFI_FEATURE_EXT_PARAM_PAGE)) {
+
+		/*
+		 * The nand_flash_detect_ext_param_page() uses the
+		 * Change Read Column command which maybe not supported
+		 * by the chip->cmdfunc. So try to update the chip->cmdfunc
+		 * now. We do not replace user supplied command function.
+		 */
+		if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
+			chip->cmdfunc = nand_command_lp;
+
+		/* The Extended Parameter Page is supported since ONFI 2.1. */
+		if (nand_flash_detect_ext_param_page(mtd, chip, p))
+			pr_info("Failed to detect the extended param page.\n");
 	}
 
 	pr_info("ONFI flash detected\n");