[PATCH] mtd: cqspi: Wait for transfer completion

[Pratyush Yadav]

On 14/09/21 05:22AM, Marek Vasut wrote:
> Wait for the read/write transfer finish bit get actually cleared,
> this does not happen immediately on at least SoCFPGA Gen5.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Jagan Teki <jagan at amarulasolutions.com>
> Cc: Vignesh R <vigneshr at ti.com>
> Cc: Pratyush Yadav <p.yadav at ti.com>
> ---
>  drivers/spi/cadence_qspi_apb.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
> index 429ee335db6..2cdf4c9c9f8 100644
> --- a/drivers/spi/cadence_qspi_apb.c
> +++ b/drivers/spi/cadence_qspi_apb.c
> @@ -858,6 +858,14 @@ cadence_qspi_apb_indirect_read_execute(struct cadence_spi_plat *plat,
>  	writel(CQSPI_REG_INDIRECTRD_DONE,
>  	       plat->regbase + CQSPI_REG_INDIRECTRD);
>  
> +	/* Check indirect done status */
> +	ret = wait_for_bit_le32(plat->regbase + CQSPI_REG_INDIRECTRD,
> +				CQSPI_REG_INDIRECTRD_DONE, 0, 10, 0);
> +	if (ret) {
> +		printf("Indirect read clear completion error (%i)\n", ret);
> +		goto failrd;
> +	}
> +

Huh, this is strange. I would expect the bit to clear immediately since 
it doesn't really do any operation on the flash. How long does it 
usually take to clear? If you don't wait for it to clear does anything 
break?

>  	return 0;
>  
>  failrd:
> @@ -1012,6 +1020,15 @@ cadence_qspi_apb_indirect_write_execute(struct cadence_spi_plat *plat,
>  	/* Clear indirect completion status */
>  	writel(CQSPI_REG_INDIRECTWR_DONE,
>  	       plat->regbase + CQSPI_REG_INDIRECTWR);
> +
> +	/* Check indirect done status */
> +	ret = wait_for_bit_le32(plat->regbase + CQSPI_REG_INDIRECTWR,
> +				CQSPI_REG_INDIRECTWR_DONE, 0, 10, 0);
> +	if (ret) {
> +		printf("Indirect write clear completion error (%i)\n", ret);
> +		goto failwr;
> +	}
> +
>  	if (bounce_buf)
>  		free(bounce_buf);
>  	return 0;
> -- 
> 2.33.0
> 

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.