[U-Boot] [PATCH] spi: cadence_qspi_apb: fix QSPI write issues

[Tan, Ley Foon]

> -----Original Message-----
> From: Ooi, Joyce <joyce.ooi at intel.com>
> Sent: Thursday, November 21, 2019 10:42 PM
> To: Jagan Teki <jagan at amarulasolutions.com>
> Cc: Tan, Ley Foon <ley.foon.tan at intel.com>; Ang, Chee Hong
> <chee.hong.ang at intel.com>; Ooi, Joyce <joyce.ooi at intel.com>; u-
> boot at lists.denx.de
> Subject: [PATCH] spi: cadence_qspi_apb: fix QSPI write issues
> 
> From: Chee Hong Ang <chee.hong.ang at intel.com>
> 
> QSPI driver perform chip select on every flash read/write access. The driver
> need to disable/enable the QSPI controller while performing chip select. This
> may cause some data lost especially the QSPI controller is configured to run
> at slower speed as it may take longer time to access the flash device.
> This patch prevent the driver from disable/enable the QSPI controller too
> soon and inadvertently halting any ongoing flash read/write access by
> ensuring the QSPI controller is always in idle mode after each read/write
> access.
> 
> Signed-off-by: Chee Hong Ang <chee.hong.ang at intel.com>
> Signed-off-by: Ooi, Joyce <joyce.ooi at intel.com>

Reviewed-by: Ley Foon Tan <ley.foon.tan at intel.com>

> ---
>  drivers/spi/cadence_qspi_apb.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
> index 55a7501..ab14a5f 100644
> --- a/drivers/spi/cadence_qspi_apb.c
> +++ b/drivers/spi/cadence_qspi_apb.c
> @@ -676,6 +676,10 @@ int
> cadence_qspi_apb_indirect_read_execute(struct cadence_spi_platdata *plat,
>  	writel(CQSPI_REG_INDIRECTRD_DONE,
>  	       plat->regbase + CQSPI_REG_INDIRECTRD);
> 
> +	/* Wait til QSPI is idle */
> +	if (!cadence_qspi_wait_idle(plat->regbase))
> +		return -EIO;
> +
>  	return 0;
> 
>  failrd:
> @@ -782,6 +786,11 @@ int
> cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata
> *plat,
>  	       plat->regbase + CQSPI_REG_INDIRECTWR);
>  	if (bounce_buf)
>  		free(bounce_buf);
> +
> +	/* Wait til QSPI is idle */
> +	if (!cadence_qspi_wait_idle(plat->regbase))
> +		return -EIO;
> +
>  	return 0;
> 
>  failwr:
> --
> 1.9.1