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Date:   Tue, 31 Aug 2021 14:28:53 +0530
From:   mdalam@codeaurora.org
To:     Miquel Raynal <miquel.raynal@bootlin.com>
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
In-Reply-To: <20210830095607.6be588fe@xps13>
References: <1629973862-7248-1-git-send-email-mdalam@codeaurora.org>
 <20210830095607.6be588fe@xps13>
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On 2021-08-30 13:26, Miquel Raynal wrote:
> 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?

   Updated in V2 patch
> 
>> 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