From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from tx2ehsobe003.messaging.microsoft.com ([65.55.88.13] helo=tx2outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UUTBV-0006DE-3c for linux-mtd@lists.infradead.org; Tue, 23 Apr 2013 02:42:22 +0000 Message-ID: <5175F56B.5040200@freescale.com> Date: Tue, 23 Apr 2013 10:43:55 +0800 From: Huang Shijie MIME-Version: 1.0 To: Brian Norris Subject: Re: [PATCH v2 3/8] mtd: get the ECC info from the Extended Parameter Page References: <1366616878-29481-1-git-send-email-b32955@freescale.com> <1366616878-29481-4-git-send-email-b32955@freescale.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: quoted-printable Cc: linux-mtd@lists.infradead.org, dwmw2@infradead.org, linux-kernel@vger.kernel.org, dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =E4=BA=8E 2013=E5=B9=B404=E6=9C=8823=E6=97=A5 05:22, Brian Norris =E5=86=99= =E9=81=93: > On Mon, Apr 22, 2013 at 12:47 AM, Huang Shijie w= rote: >> 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 codewor= d >> size is not 512 bytes, then the @ecc_bits is 0xff. The host _SHOULD_ t= hen >> read the Extended ECC information that is part of the extended paramet= er >> page to retrieve the ECC requirements for this device. >> >> This patch implement the reading of the Extended Parameter Page, and p= arses >> 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 >> --- >> drivers/mtd/nand/nand_base.c | 54 ++++++++++++++++++++++++++++++++= ++++++++++ >> 1 files changed, 54 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base= .c >> index beff911..48ff097 100644 >> --- a/drivers/mtd/nand/nand_base.c >> +++ b/drivers/mtd/nand/nand_base.c >> @@ -2846,6 +2846,56 @@ static u16 onfi_crc16(u16 crc, u8 const *p, siz= e_t len) >> return crc; >> } >> >> +/* Parse the Extended Parameter Page. */ >> +static void nand_flash_detect_ext_param_page(struct mtd_info *mtd, >> + struct nand_chip *chip, struct nand_onfi_params *p, in= t last) >> +{ > I think we want a return code (int) for this function. It obviously > can fail, and the caller needs to know this. I not sure who will uses ecc_strength/ecc_size, except the gpmi. So i ignore the return value. If you think we should add it, i will add it. > The "last" parameter is not very obvious until you read the whole > function, where you see that this function assumes a lot about the > caller. Please address the comments below and/or fully document the > parameters and calling context for this function. > ok. I can add more comments. >> + struct onfi_ext_param_page *ep; >> + struct onfi_ext_section *s; >> + struct onfi_ext_ecc_info *ecc; >> + uint8_t *cursor; >> + int len; >> + int i; >> + >> + len =3D le16_to_cpu(p->ext_param_page_length) * 16; >> + ep =3D kcalloc(1, max_t(int, len, sizeof(*p)), GFP_KERNEL); >> + if (!ep) >> + goto ext_out; >> + >> + /* >> + * Skip the ONFI Parameter Pages. >> + * The Change Read Columm command may does not works here. > Why not? > You can give me a fix patch which bases on my patch set. I can test it. :) I tried to use the Change-read-columm command, but failed. >> + */ >> + for (i =3D last + 1; i< p->num_of_param_pages; i++) >> + chip->read_buf(mtd, (uint8_t *)ep, sizeof(*p)); > You never sent a command to the chip. How can you expect to read from i= t? we have sent a command in the nand_flash_detect_onfi(). > It seems that you are writing this function with the assumption of a > particular calling context (a context in which the last command was > CMD_PARAM). IMO, it would make a lot more sense that this function > actually send its own CMD_PARAM followed by either X bytes of skipped > read_buf() or a change read column command. Then it doesn't need the > "last" argument, and its usage makes much more sense. > I added the "last" argument just because the Change-read-column command=20 did not works. thanks Huang Shijie