[U-Boot] [PATCH 1/6] spi: fsl_qspi: Fix DDR mode setting for latest iMX platforms

[Ye Li]

Please ignore the patch set. I will send out V2 to remove 2 patches.

> On latest iMX platforms like iMX7D/iMX6UL/iMX8MQ, the QSPI controller
> is updated to have TDH field in FLSHCR register. According to reference
> manual, this TDH must be set to 1 when DDR_EN is set. Otherwise, the TX
> DDR delay logic won't be enabled.
> 
> Another issue in DDR mode is the MCR register will be overwritten in
> every read/write/erase operation. This causes DDR_EN been cleared while
> TDH=1, then no clk2x output for TX data shift and all operations will
> fail.
> 
> Signed-off-by: Ye Li <ye.li at nxp.com>
> ---
>  drivers/spi/fsl_qspi.c | 30 ++++++++++++++++--------------
>  1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
> index 41abe19..8845986 100644
> --- a/drivers/spi/fsl_qspi.c
> +++ b/drivers/spi/fsl_qspi.c
> @@ -399,7 +399,7 @@ static inline void qspi_ahb_read(struct fsl_qspi_priv *priv, u8 *rxbuf, int len)
>  
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  
>  	rx_addr = (void *)(uintptr_t)(priv->cur_amba_base + priv->sf_addr);
>  	/* Read out the data directly from the AHB buffer. */
> @@ -429,6 +429,14 @@ static void qspi_enable_ddr_mode(struct fsl_qspi_priv *priv)
>  	reg |= BIT(29);
>  
>  	qspi_write32(priv->flags, &regs->mcr, reg);
> +
> +	/* Enable the TDH to 1 for some platforms like imx6ul, imx7d, etc
> +	 * These two bits are reserved on other platforms
> +	 */
> +	reg = qspi_read32(priv->flags, &regs->flshcr);
> +	reg &= ~(BIT(17));
> +	reg |= BIT(16);
> +	qspi_write32(priv->flags, &regs->flshcr, reg);
>  }
>  
>  /*
> @@ -482,7 +490,7 @@ static void qspi_op_rdbank(struct fsl_qspi_priv *priv, u8 *rxbuf, u32 len)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	qspi_write32(priv->flags, &regs->sfar, priv->cur_amba_base);
> @@ -527,7 +535,7 @@ static void qspi_op_rdid(struct fsl_qspi_priv *priv, u32 *rxbuf, u32 len)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	qspi_write32(priv->flags, &regs->sfar, priv->cur_amba_base);
> @@ -573,7 +581,7 @@ static void qspi_op_read(struct fsl_qspi_priv *priv, u32 *rxbuf, u32 len)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	to_or_from = priv->sf_addr + priv->cur_amba_base;
> @@ -625,7 +633,7 @@ static void qspi_op_write(struct fsl_qspi_priv *priv, u8 *txbuf, u32 len)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	status_reg = 0;
> @@ -700,7 +708,7 @@ static void qspi_op_rdsr(struct fsl_qspi_priv *priv, void *rxbuf, u32 len)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	qspi_write32(priv->flags, &regs->sfar, priv->cur_amba_base);
> @@ -737,7 +745,7 @@ static void qspi_op_erase(struct fsl_qspi_priv *priv)
>  	mcr_reg = qspi_read32(priv->flags, &regs->mcr);
>  	qspi_write32(priv->flags, &regs->mcr,
>  		     QSPI_MCR_CLR_RXF_MASK | QSPI_MCR_CLR_TXF_MASK |
> -		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_END_CFD_LE);
> +		     mcr_reg);
>  	qspi_write32(priv->flags, &regs->rbct, QSPI_RBCT_RXBRD_USEIPS);
>  
>  	to_or_from = priv->sf_addr + priv->cur_amba_base;
> @@ -900,15 +908,9 @@ static int fsl_qspi_probe(struct udevice *bus)
>  		return ret;
>  	}
>  
> -	mcr_val = qspi_read32(priv->flags, &priv->regs->mcr);
> -
> -	/* Set endianness to LE for i.mx */
> -	if (IS_ENABLED(CONFIG_MX6) || IS_ENABLED(CONFIG_MX7))
> -		mcr_val = QSPI_MCR_END_CFD_LE;
> -
>  	qspi_write32(priv->flags, &priv->regs->mcr,
>  		     QSPI_MCR_RESERVED_MASK | QSPI_MCR_MDIS_MASK |
> -		     (mcr_val & QSPI_MCR_END_CFD_MASK));
> +		     QSPI_MCR_END_CFD_LE);
>  
>  	qspi_cfg_smpr(priv, ~(QSPI_SMPR_FSDLY_MASK | QSPI_SMPR_DDRSMP_MASK |
>  		QSPI_SMPR_FSPHS_MASK | QSPI_SMPR_HSENA_MASK), 0);
>