Re: [PATCH v2 2/3] mtd: rawnand: qcom: Fix onfi param page read

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Fri, Nov 22, 2024 at 02:29:32PM +0530, Md Sadre Alam wrote:

Please change subject to:

mtd: rawnand: qcom: Fix last codeword read in qcom_param_page_type_exec()

> For QPIC V2 onwards there is a separate register to read
> last code word "QPIC_NAND_READ_LOCATION_LAST_CW_n".
> 
> qcom_param_page_type_exec() is used to read only one code word
> If it will get configure number of code words to 1 in QPIC_NAND_DEV0_CFG0

"If it configures the number of..."

> register then QPIC controller thinks its reading the last code word,
> since 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 QPIC buffer to system memory.
> 
> Without this change page read was failing with timeout error
> 
> / # hexdump -C /dev/mtd1
> [  129.206113] qcom-nandc 1cc8000.nand-controller: failure to read page/oob
> hexdump: /dev/mtd1: Connection timed out
> 
> This issue only seen on SDX targets since SDX target used QPICv2. But
> same working on IPQ targets since IPQ used QPICv1.
> 
> Cc: stable@vger.kernel.org
> Fixes: 89550beb098e ("mtd: rawnand: qcom: Implement exec_op()")
> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
> 
> Change in [v2]
> 
> * Updated commit message
> 
> * Added stable kernel tag
> 
> * Replaced the buf_count value of 512 with the len in bytes.
> 
> Change in [v1]
> 
> * Resolved the issue with reading a single code word in the parameter
>   page read
> 
>  drivers/mtd/nand/raw/qcom_nandc.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index cc59461df72e..31ec3db1246d 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -2859,7 +2859,12 @@ static int qcom_param_page_type_exec(struct nand_chip *chip,  const struct nand_
>  	const struct nand_op_instr *instr = NULL;
>  	unsigned int op_id = 0;
>  	unsigned int len = 0;
> -	int ret;
> +	int ret, reg_base;
> +
> +	reg_base = NAND_READ_LOCATION_0;
> +
> +	if (nandc->props->qpic_v2)
> +		reg_base = NAND_READ_LOCATION_LAST_CW_0;
>  
>  	ret = qcom_parse_instructions(chip, subop, &q_op);
>  	if (ret)
> @@ -2911,7 +2916,10 @@ static int qcom_param_page_type_exec(struct nand_chip *chip,  const struct nand_
>  	op_id = q_op.data_instr_idx;
>  	len = nand_subop_get_data_len(subop, op_id);
>  
> -	nandc_set_read_loc(chip, 0, 0, 0, len, 1);

nandc_set_read_loc() does changes the register offset based on QPIC version. So
what exactly you are trying to fix here?

- Mani

> +	if (nandc->props->qpic_v2)
> +		nandc_set_read_loc_last(chip, reg_base, 0, len, 1);
> +	else
> +		nandc_set_read_loc_first(chip, reg_base, 0, len, 1);
>  
>  	if (!nandc->props->qpic_v2) {
>  		write_reg_dma(nandc, NAND_DEV_CMD_VLD, 1, 0);
> -- 
> 2.34.1
> 

-- 
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