linux-kernel - Re: [PATCH] mtd: rawnand: qcom: update last code word register

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Message-ID: <20201231105303.GI7345@thinkpad>
Date:   Thu, 31 Dec 2020 16:23:03 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Md Sadre Alam <mdalam@...eaurora.org>
Cc:     miquel.raynal@...tlin.com, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org, boris.brezillon@...labora.com,
        sricharan@...eaurora.org
Subject: Re: [PATCH] mtd: rawnand: qcom: update last code word register

On Thu, Dec 17, 2020 at 07:32:56PM +0530, Md Sadre Alam wrote:
> From QPIC version 2.0 onwards new register got added to
> read last codeword. This change will update the same.
> 
> For first three code word READ_LOCATION_n register will be
> use.For last code wrod READ_LOCATION_LAST_CW_n register will be
> use.
> 
> Signed-off-by: Md Sadre Alam <mdalam@...eaurora.org>
> ---
>  drivers/mtd/nand/raw/qcom_nandc.c | 79 +++++++++++++++++++++++++++++++++------
>  1 file changed, 67 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index 667e4bf..eaef51d 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -48,6 +48,10 @@
>  #define	NAND_READ_LOCATION_1		0xf24
>  #define	NAND_READ_LOCATION_2		0xf28
>  #define	NAND_READ_LOCATION_3		0xf2c
> +#define NAND_READ_LOCATION_LAST_CW_0    0xf40
> +#define NAND_READ_LOCATION_LAST_CW_1    0xf44
> +#define NAND_READ_LOCATION_LAST_CW_2    0xf48
> +#define NAND_READ_LOCATION_LAST_CW_3    0xf4c

Please keep the alignment as before.

>  
>  /* dummy register offsets, used by write_reg_dma */
>  #define	NAND_DEV_CMD1_RESTORE		0xdead
> @@ -187,6 +191,12 @@ nandc_set_reg(nandc, NAND_READ_LOCATION_##reg,			\
>  	      ((size) << READ_LOCATION_SIZE) |			\
>  	      ((is_last) << READ_LOCATION_LAST))
>  
> +#define nandc_set_read_loc_last(nandc, reg, offset, size, is_last)	\
> +nandc_set_reg(nandc, NAND_READ_LOCATION_LAST_CW_##reg,			\
> +	      ((offset) << READ_LOCATION_OFFSET) |		\
> +	      ((size) << READ_LOCATION_SIZE) |			\
> +	      ((is_last) << READ_LOCATION_LAST))
> +
>  /*
>   * Returns the actual register address for all NAND_DEV_ registers
>   * (i.e. NAND_DEV_CMD0, NAND_DEV_CMD1, NAND_DEV_CMD2 and NAND_DEV_CMD_VLD)
> @@ -316,6 +326,10 @@ struct nandc_regs {
>  	__le32 read_location1;
>  	__le32 read_location2;
>  	__le32 read_location3;
> +	__le32 read_location_last0;
> +	__le32 read_location_last1;
> +	__le32 read_location_last2;
> +	__le32 read_location_last3;
>  
>  	__le32 erased_cw_detect_cfg_clr;
>  	__le32 erased_cw_detect_cfg_set;
> @@ -644,6 +658,14 @@ static __le32 *offset_to_nandc_reg(struct nandc_regs *regs, int offset)
>  		return &regs->read_location2;
>  	case NAND_READ_LOCATION_3:
>  		return &regs->read_location3;
> +	case NAND_READ_LOCATION_LAST_CW_0:
> +		return &regs->read_location_last0;
> +	case NAND_READ_LOCATION_LAST_CW_1:
> +		return &regs->read_location_last1;
> +	case NAND_READ_LOCATION_LAST_CW_2:
> +		return &regs->read_location_last2;
> +	case NAND_READ_LOCATION_LAST_CW_3:
> +		return &regs->read_location_last3;
>  	default:
>  		return NULL;
>  	}
> @@ -719,9 +741,13 @@ static void update_rw_regs(struct qcom_nand_host *host, int num_cw, bool read)
>  	nandc_set_reg(nandc, NAND_READ_STATUS, host->clrreadstatus);
>  	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
>  
> -	if (read)
> +	if (read) {
> +		if (nandc->props->qpic_v2)
> +			nandc_set_read_loc_last(nandc, 0, 0, host->use_ecc ?
> +					host->cw_data : host->cw_size, 1);

Forgot to add else? Otherwise both NAND_READ_LOCATION_n and NAND_READ_LOCATION_LAST_CW_n
will be used.

>  		nandc_set_read_loc(nandc, 0, 0, host->use_ecc ?
>  				   host->cw_data : host->cw_size, 1);
> +	}
>  }
>  
>  /*
> @@ -1096,9 +1122,13 @@ static void config_nand_page_read(struct qcom_nand_controller *nandc)
>  static void
>  config_nand_cw_read(struct qcom_nand_controller *nandc, bool use_ecc)
>  {
> -	if (nandc->props->is_bam)
> +	if (nandc->props->is_bam) {
> +		if (nandc->props->qpic_v2)
> +			write_reg_dma(nandc, NAND_READ_LOCATION_LAST_CW_0,
> +				      4, NAND_BAM_NEXT_SGL);
>  		write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
>  			      NAND_BAM_NEXT_SGL);

Don't you need to modify the number of registers to write? It can't be 4 all the
time if NAND_READ_LOCATION_LAST_CW_0 is used.

> +	}
>  
>  	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
>  	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
> @@ -1633,16 +1663,28 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
>  	}
>  
>  	if (nandc->props->is_bam) {
> -		nandc_set_read_loc(nandc, 0, read_loc, data_size1, 0);
> +		if (nandc->props->qpic_v2 && cw == (ecc->steps - 1))
> +			nandc_set_read_loc_last(nandc, 0, read_loc, data_size1, 0);
> +		else
> +			nandc_set_read_loc(nandc, 0, read_loc, data_size1, 0);

IIUC nandc_set_read_loc_last() is only needed to read the last codeword which is
handled by the last command in this function:

nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);

>  		read_loc += data_size1;
>  
> -		nandc_set_read_loc(nandc, 1, read_loc, oob_size1, 0);
> +		if (nandc->props->qpic_v2 && cw == (ecc->steps - 1))
> +			nandc_set_read_loc_last(nandc, 1, read_loc, oob_size1, 0);
> +		else
> +			nandc_set_read_loc(nandc, 1, read_loc, oob_size1, 0);
>  		read_loc += oob_size1;
>  
> -		nandc_set_read_loc(nandc, 2, read_loc, data_size2, 0);
> +		if (nandc->props->qpic_v2 && cw == (ecc->steps - 1))
> +			nandc_set_read_loc_last(nandc, 2, read_loc, data_size2, 0);
> +		else
> +			nandc_set_read_loc(nandc, 2, read_loc, data_size2, 0);
>  		read_loc += data_size2;
>  
> -		nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
> +		if (nandc->props->qpic_v2 && cw == (ecc->steps - 1))
> +			nandc_set_read_loc_last(nandc, 3, read_loc, oob_size2, 0);
> +		else
> +			nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
>  	}
>  
>  	config_nand_cw_read(nandc, false);
> @@ -1873,14 +1915,27 @@ static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
>  
>  		if (nandc->props->is_bam) {
>  			if (data_buf && oob_buf) {
> -				nandc_set_read_loc(nandc, 0, 0, data_size, 0);
> -				nandc_set_read_loc(nandc, 1, data_size,
> -						   oob_size, 1);
> +				if (nandc->props->qpic_v2 && i == (ecc->steps - 1)) {
> +					nandc_set_read_loc_last(nandc, 0, 0, data_size, 0);

Why do you need this? Can't you use nandc_set_read_loc()? Same for below cases.

Thanks,
Mani

> +					nandc_set_read_loc_last(nandc, 1, data_size,
> +								oob_size, 1);
> +				} else {
> +					nandc_set_read_loc(nandc, 0, 0, data_size, 0);
> +					nandc_set_read_loc(nandc, 1, data_size,
> +							   oob_size, 1);
> +				}
>  			} else if (data_buf) {
> -				nandc_set_read_loc(nandc, 0, 0, data_size, 1);
> +				if (nandc->props->qpic_v2 && i == (ecc->steps - 1))
> +					nandc_set_read_loc_last(nandc, 0, 0, data_size, 1);
> +				else
> +					nandc_set_read_loc(nandc, 0, 0, data_size, 1);
>  			} else {
> -				nandc_set_read_loc(nandc, 0, data_size,
> -						   oob_size, 1);
> +				if (nandc->props->qpic_v2 && i == (ecc->steps - 1))
> +					nandc_set_read_loc_last(nandc, 0, data_size,
> +								oob_size, 1);
> +				else
> +					nandc_set_read_loc(nandc, 0, data_size,
> +							   oob_size, 1);
>  			}
>  		}
>  
> -- 
> 2.7.4
>