[U-Boot] [PATCH v3] driver: spi: fsl-qspi: disable AHB buffer prefetch

[york sun]

On 07/11/2016 08:00 PM, Yunhui Cui wrote:
> From: Yunhui Cui <yunhui.cui at nxp.com>
>
> Errata: A-009282: QuadSPI data pre-fetch can result in incorrect data
> We need this errata workaround when CONFIG_SYS_FSL_QSPI_AHB is enabled.
>
> Signed-off-by: Yunhui Cui <yunhui.cui at nxp.com>
> ---
>   drivers/spi/fsl_qspi.c | 12 +++++++++++-
>   1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
> index 75cbab2..0354e20 100644
> --- a/drivers/spi/fsl_qspi.c
> +++ b/drivers/spi/fsl_qspi.c
> @@ -438,13 +438,23 @@ static void qspi_enable_ddr_mode(struct fsl_qspi_priv *priv)
>   static void qspi_init_ahb_read(struct fsl_qspi_priv *priv)
>   {
>   	struct fsl_qspi_regs *regs = priv->regs;
> +	int rx_size = 0x80;

Wrap this with ifdef, or you will have compiling warning when the macro 
is not defined.

York


>
>   	/* AHB configuration for access buffer 0/1/2 .*/
>   	qspi_write32(priv->flags, &regs->buf0cr, QSPI_BUFXCR_INVALID_MSTRID);
>   	qspi_write32(priv->flags, &regs->buf1cr, QSPI_BUFXCR_INVALID_MSTRID);
>   	qspi_write32(priv->flags, &regs->buf2cr, QSPI_BUFXCR_INVALID_MSTRID);
> +
> +#ifdef CONFIG_SYS_FSL_ERRATUM_A009282
> +	/*A-009282: QuadSPI data pre-fetch can result in incorrect data
> +	 *Workaround: Keep the read data size to 64 bits (8 Bytes), which
> +	 *disables the prefetch on the AHB buffer,and prevents this issue
> +	 *from occurring.
> +	*/
> +	rx_size = 0x1;
> +#endif
>   	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
> -		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
> +		     (rx_size << QSPI_BUF3CR_ADATSZ_SHIFT));
>
>   	/* We only use the buffer3 */
>   	qspi_write32(priv->flags, &regs->buf0ind, 0);
>