[PATCH v2 3/7] drm: mxsfb: Wrap FIFO reset and comments into mxsfb_reset_block()

[Lucas Stach]

Am Freitag, dem 11.03.2022 um 18:05 +0100 schrieb Marek Vasut:
> Wrap FIFO reset and comments into mxsfb_reset_block(), this is a clean up.
> No functional change.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Alexander Stein <alexander.stein at ew.tq-group.com>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Cc: Lucas Stach <l.stach at pengutronix.de>
> Cc: Peng Fan <peng.fan at nxp.com>
> Cc: Robby Cai <robby.cai at nxp.com>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Cc: Stefan Agner <stefan at agner.ch>

Reviewed-by: Lucas Stach <l.stach at pengutronix.de>

> ---
> V2: No change
> ---
>  drivers/gpu/drm/mxsfb/mxsfb_kms.c | 36 +++++++++++++++++--------------
>  1 file changed, 20 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> index 657b6afbbf1f9..015b289d93a3c 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> @@ -183,6 +183,12 @@ static int mxsfb_reset_block(struct mxsfb_drm_private *mxsfb)
>  {
>  	int ret;
>  
> +	/*
> +	 * It seems, you can't re-program the controller if it is still
> +	 * running. This may lead to shifted pictures (FIFO issue?), so
> +	 * first stop the controller and drain its FIFOs.
> +	 */
> +
>  	ret = clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_SFTRST);
>  	if (ret)
>  		return ret;
> @@ -193,7 +199,20 @@ static int mxsfb_reset_block(struct mxsfb_drm_private *mxsfb)
>  	if (ret)
>  		return ret;
>  
> -	return clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_CLKGATE);
> +	ret = clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_CLKGATE);
> +	if (ret)
> +		return ret;
> +
> +	/* Clear the FIFOs */
> +	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET);
> +	readl(mxsfb->base + LCDC_CTRL1);
> +	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_CLR);
> +	readl(mxsfb->base + LCDC_CTRL1);
> +
> +	if (mxsfb->devdata->has_overlay)
> +		writel(0, mxsfb->base + LCDC_AS_CTRL);
> +
> +	return 0;
>  }
>  
>  static dma_addr_t mxsfb_get_fb_paddr(struct drm_plane *plane)
> @@ -220,26 +239,11 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb,
>  	u32 vdctrl0, vsync_pulse_len, hsync_pulse_len;
>  	int err;
>  
> -	/*
> -	 * It seems, you can't re-program the controller if it is still
> -	 * running. This may lead to shifted pictures (FIFO issue?), so
> -	 * first stop the controller and drain its FIFOs.
> -	 */
> -
>  	/* Mandatory eLCDIF reset as per the Reference Manual */
>  	err = mxsfb_reset_block(mxsfb);
>  	if (err)
>  		return;
>  
> -	/* Clear the FIFOs */
> -	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET);
> -	readl(mxsfb->base + LCDC_CTRL1);
> -	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_CLR);
> -	readl(mxsfb->base + LCDC_CTRL1);
> -
> -	if (mxsfb->devdata->has_overlay)
> -		writel(0, mxsfb->base + LCDC_AS_CTRL);
> -
>  	mxsfb_set_formats(mxsfb, bus_format);
>  
>  	if (mxsfb->bridge && mxsfb->bridge->timings)