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Date:   Mon, 30 Aug 2021 09:56:07 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Md Sadre Alam <mdalam@codeaurora.org>
Cc:     mani@kernel.org, boris.brezillon@collabora.com,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
        sricharan@codeaurora.org
Subject: Re: [PATCH] mtd: rawnand: qcom: Update code word value for raw read
Message-ID: <20210830095607.6be588fe@xps13>
In-Reply-To: <1629973862-7248-1-git-send-email-mdalam@codeaurora.org>
References: <1629973862-7248-1-git-send-email-mdalam@codeaurora.org>
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Hello

Md Sadre Alam <mdalam@codeaurora.org> wrote on Thu, 26 Aug 2021
16:01:02 +0530:

> From QPIC V2 onwards there is a separate register to read
> last code word "QPIC_NAND_READ_LOCATION_LAST_CW_n".
> 
> qcom_nandc_read_cw_raw() is used to read only one code word
> at a time. If we will configure number of code words to 1 in
> in QPIC_NAND_DEV0_CFG0 register then QPIC controller thinks
> its reading the last code word, since from QPIC V2 onwards
> we are having separate register to read the last code word,
> we have to configure "QPIC_NAND_READ_LOCATION_LAST_CW_n"
> register to fetch data from controller buffer to system
> memory.

Fixes/Cc: stable tags are missing?

> Signed-off-by: Md Sadre Alam <mdalam@codeaurora.org>
> ---
>  drivers/mtd/nand/raw/qcom_nandc.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index ef0bade..04e6f7b 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -1676,13 +1676,17 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
>  	struct nand_ecc_ctrl *ecc = &chip->ecc;
>  	int data_size1, data_size2, oob_size1, oob_size2;
>  	int ret, reg_off = FLASH_BUF_ACC, read_loc = 0;
> +	int raw_cw = cw;
>  
>  	nand_read_page_op(chip, page, 0, NULL, 0);
>  	host->use_ecc = false;
>  
> +	if (nandc->props->qpic_v2)
> +		raw_cw = ecc->steps - 1;
> +
>  	clear_bam_transaction(nandc);
>  	set_address(host, host->cw_size * cw, page);
> -	update_rw_regs(host, 1, true, cw);
> +	update_rw_regs(host, 1, true, raw_cw);
>  	config_nand_page_read(chip);
>  
>  	data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
> @@ -1711,7 +1715,7 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
>  		nandc_set_read_loc(chip, cw, 3, read_loc, oob_size2, 1);
>  	}
>  
> -	config_nand_cw_read(chip, false, cw);
> +	config_nand_cw_read(chip, false, raw_cw);
>  
>  	read_data_dma(nandc, reg_off, data_buf, data_size1, 0);
>  	reg_off += data_size1;

Thanks,
Miquèl