From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.bootlin.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fMUqt-0001l9-Rd for linux-mtd@lists.infradead.org; Sat, 26 May 2018 08:47:05 +0000 Date: Sat, 26 May 2018 10:46:29 +0200 From: Miquel Raynal To: Abhishek Sahu Cc: Boris Brezillon , David Woodhouse , Brian Norris , Marek Vasut , Richard Weinberger , Cyrille Pitchen , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Andy Gross , Archit Taneja Subject: Re: [PATCH v3 13/16] mtd: rawnand: qcom: minor code reorganization for bad block check Message-ID: <20180526104629.74315561@xps13> In-Reply-To: <1527250904-21988-14-git-send-email-absahu@codeaurora.org> References: <1527250904-21988-1-git-send-email-absahu@codeaurora.org> <1527250904-21988-14-git-send-email-absahu@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Abhishek, On Fri, 25 May 2018 17:51:41 +0530, Abhishek Sahu wrote: > The QCOM NAND controller layout is such that, the bad block byte > offset for last codeword will come to first byte in spare area. "is the first spare byte"? > Currently, the raw read for last codeword is being done with > copy_last_cw function. It does following 2 things: "It does the following:" >=20 > 1. Read the last codeword bytes from NAND chip to NAND > controller internal HW buffer. > 2. Copy all these bytes from HW buffer to actual buffer. >=20 > For bad block check, maximum two bytes are required so instead of > copying the complete bytes in step 2, only those bbm_size bytes > can be copied. >=20 > This patch does minor code reorganization for the same. After > this, copy_last_cw function won=E2=80=99t be required. "This patch does minor code reorganization to just retrieve these two bytes when checking for bad blocks, allowing to remove copy_last_cw() now useless." >=20 > Signed-off-by: Abhishek Sahu > --- > * Changes from v2: > 1. Changed commit message and comments slightly >=20 > * Changes from v1: > NEW CHANGE >=20 > drivers/mtd/nand/raw/qcom_nandc.c | 66 +++++++++++++++------------------= ------ > 1 file changed, 25 insertions(+), 41 deletions(-) >=20 > diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qco= m_nandc.c > index d693b5f..f72bc8a 100644 > --- a/drivers/mtd/nand/raw/qcom_nandc.c > +++ b/drivers/mtd/nand/raw/qcom_nandc.c > @@ -1769,41 +1769,6 @@ static int read_page_ecc(struct qcom_nand_host *ho= st, u8 *data_buf, > return parse_read_errors(host, data_buf_start, oob_buf_start); > } > =20 > -/* > - * a helper that copies the last step/codeword of a page (containing fre= e oob) > - * into our local buffer > - */ > -static int copy_last_cw(struct qcom_nand_host *host, int page) > -{ > - struct nand_chip *chip =3D &host->chip; > - struct qcom_nand_controller *nandc =3D get_qcom_nand_controller(chip); > - struct nand_ecc_ctrl *ecc =3D &chip->ecc; > - int size; > - int ret; > - > - clear_read_regs(nandc); > - > - size =3D host->use_ecc ? host->cw_data : host->cw_size; > - > - /* prepare a clean read buffer */ > - memset(nandc->data_buffer, 0xff, size); > - > - set_address(host, host->cw_size * (ecc->steps - 1), page); > - update_rw_regs(host, 1, true); > - > - config_nand_single_cw_page_read(nandc); > - > - read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, size, 0); > - > - ret =3D submit_descs(nandc); > - if (ret) > - dev_err(nandc->dev, "failed to copy last codeword\n"); > - > - free_descs(nandc); > - > - return ret; > -} > - > /* implements ecc->read_page() */ > static int qcom_nandc_read_page(struct mtd_info *mtd, struct nand_chip *= chip, > uint8_t *buf, int oob_required, int page) > @@ -2118,6 +2083,7 @@ static int qcom_nandc_block_bad(struct mtd_info *mt= d, loff_t ofs) > struct nand_ecc_ctrl *ecc =3D &chip->ecc; > int page, ret, bbpos, bad =3D 0; > u32 flash_status; > + u8 *bbm_bytes_buf =3D chip->data_buf; > =20 > page =3D (int)(ofs >> chip->page_shift) & chip->pagemask; > =20 > @@ -2128,11 +2094,31 @@ static int qcom_nandc_block_bad(struct mtd_info *= mtd, loff_t ofs) > * that contains the BBM > */ > host->use_ecc =3D false; > + bbpos =3D mtd->writesize - host->cw_size * (ecc->steps - 1); Are we sure there is no layout with only 1 step? > =20 > clear_bam_transaction(nandc); > - ret =3D copy_last_cw(host, page); > - if (ret) > + clear_read_regs(nandc); > + > + set_address(host, host->cw_size * (ecc->steps - 1), page); > + update_rw_regs(host, 1, true); > + > + /* > + * The last codeword data will be copied from NAND device to NAND > + * controller internal HW buffer. Copy only required BBM size bytes > + * from this HW buffer to bbm_bytes_buf which is present at > + * bbpos offset. > + */ > + nandc_set_read_loc(nandc, 0, bbpos, host->bbm_size, 1); > + config_nand_single_cw_page_read(nandc); > + read_data_dma(nandc, FLASH_BUF_ACC + bbpos, bbm_bytes_buf, > + host->bbm_size, 0); > + > + ret =3D submit_descs(nandc); > + free_descs(nandc); > + if (ret) { > + dev_err(nandc->dev, "failed to copy bad block bytes\n"); > goto err; > + } > =20 > flash_status =3D le32_to_cpu(nandc->reg_read_buf[0]); > =20 > @@ -2141,12 +2127,10 @@ static int qcom_nandc_block_bad(struct mtd_info *= mtd, loff_t ofs) > goto err; > } > =20 > - bbpos =3D mtd->writesize - host->cw_size * (ecc->steps - 1); > - > - bad =3D nandc->data_buffer[bbpos] !=3D 0xff; > + bad =3D bbm_bytes_buf[0] !=3D 0xff; This is suspect as it still points to the beginning of the data buffer. Can you please check you did not meant bbm_bytes_buf[bbpos]? > =20 > if (chip->options & NAND_BUSWIDTH_16) > - bad =3D bad || (nandc->data_buffer[bbpos + 1] !=3D 0xff); > + bad =3D bad || (bbm_bytes_buf[1] !=3D 0xff); > err: > return bad; > } Thanks, Miqu=C3=A8l