Re: [PATCH v4 6/9] drm/bridge: cdns: Separate DSI and D-PHY configuration

[Sean Paul]

On Wed, Jan 09, 2019 at 10:33:23AM +0100, Maxime Ripard wrote:
> The current configuration of the DSI bridge and its associated D-PHY is
> intertwined. In order to ease the future conversion to the phy framework
> for the D-PHY part, let's split the configuration in two.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/bridge/cdns-dsi.c | 96 ++++++++++++++++++++++----------
>  1 file changed, 68 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
> index ce9496d13986..3ac6dd524b6d 100644
> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
> @@ -545,6 +545,11 @@ bridge_to_cdns_dsi_input(struct drm_bridge *bridge)
>  	return container_of(bridge, struct cdns_dsi_input, bridge);
>  }
>  
> +static unsigned int mode_to_dpi_hfp(const struct drm_display_mode *mode)
> +{
> +	return mode->crtc_hsync_start - mode->crtc_hdisplay;
> +}
> +
>  static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
>  				     struct cdns_dphy_cfg *cfg,
>  				     unsigned int dpi_htotal,
> @@ -731,14 +736,12 @@ static unsigned int dpi_to_dsi_timing(unsigned int dpi_timing,
>  static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
>  			     const struct drm_display_mode *mode,
>  			     struct cdns_dsi_cfg *dsi_cfg,
> -			     struct cdns_dphy_cfg *dphy_cfg,
>  			     bool mode_valid_check)
>  {
> -	unsigned long dsi_htotal = 0, dsi_hss_hsa_hse_hbp = 0;
>  	struct cdns_dsi_output *output = &dsi->output;
> -	unsigned int dsi_hfp_ext = 0, dpi_hfp, tmp;
> +	unsigned int tmp;
>  	bool sync_pulse = false;
> -	int bpp, nlanes, ret;
> +	int bpp, nlanes;
>  
>  	memset(dsi_cfg, 0, sizeof(*dsi_cfg));
>  
> @@ -757,8 +760,6 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
>  		       mode->crtc_hsync_end : mode->crtc_hsync_start);
>  
>  	dsi_cfg->hbp = dpi_to_dsi_timing(tmp, bpp, DSI_HBP_FRAME_OVERHEAD);
> -	dsi_htotal += dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> -	dsi_hss_hsa_hse_hbp += dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
>  
>  	if (sync_pulse) {
>  		if (mode_valid_check)
> @@ -768,49 +769,90 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
>  
>  		dsi_cfg->hsa = dpi_to_dsi_timing(tmp, bpp,
>  						 DSI_HSA_FRAME_OVERHEAD);
> -		dsi_htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> -		dsi_hss_hsa_hse_hbp += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
>  	}
>  
>  	dsi_cfg->hact = dpi_to_dsi_timing(mode_valid_check ?
>  					  mode->hdisplay : mode->crtc_hdisplay,
>  					  bpp, 0);
> -	dsi_htotal += dsi_cfg->hact;
> +	dsi_cfg->hfp = dpi_to_dsi_timing(mode_to_dpi_hfp(mode), bpp,
> +					 DSI_HFP_FRAME_OVERHEAD);

We're throwing away the mode_valid_check switch here to flip between crtc_h*
value and h* value. Is that intentional? We're using it above for hdisplay, so
it's a bit confusing.

>  
> -	if (mode_valid_check)
> -		dpi_hfp = mode->hsync_start - mode->hdisplay;
> -	else
> -		dpi_hfp = mode->crtc_hsync_start - mode->crtc_hdisplay;
> +	return 0;
> +}
> +
> +static int cdns_dphy_validate(struct cdns_dsi *dsi,
> +			      struct cdns_dsi_cfg *dsi_cfg,
> +			      struct cdns_dphy_cfg *dphy_cfg,
> +			      const struct drm_display_mode *mode,
> +			      bool mode_valid_check)
> +{
> +	struct cdns_dsi_output *output = &dsi->output;
> +	unsigned long dsi_htotal;
> +	unsigned int dsi_hfp_ext = 0;
> +
> +	int ret;
>  
> -	dsi_cfg->hfp = dpi_to_dsi_timing(dpi_hfp, bpp, DSI_HFP_FRAME_OVERHEAD);
> +	dsi_htotal = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> +	if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> +		dsi_htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> +
> +	dsi_htotal += dsi_cfg->hact;
>  	dsi_htotal += dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
>  
>  	if (mode_valid_check)
>  		ret = cdns_dsi_get_dphy_pll_cfg(dsi->dphy, dphy_cfg,
> -						mode->htotal, bpp,
> +						mode->htotal,
>  						mode->clock * 1000,
> -						dsi_htotal, nlanes,
> +						mipi_dsi_pixel_format_to_bpp(output->dev->format),
> +						dsi_htotal,
> +						output->dev->lanes,
>  						&dsi_hfp_ext);
>  	else
>  		ret = cdns_dsi_get_dphy_pll_cfg(dsi->dphy, dphy_cfg,
> -						mode->crtc_htotal, bpp,
> +						mode->crtc_htotal,
> +						mipi_dsi_pixel_format_to_bpp(output->dev->format),
>  						mode->crtc_clock * 1000,
> -						dsi_htotal, nlanes,
> +						dsi_htotal,
> +						output->dev->lanes,
>  						&dsi_hfp_ext);
> -
>  	if (ret)
>  		return ret;
>  
>  	dsi_cfg->hfp += dsi_hfp_ext;
> -	dsi_htotal += dsi_hfp_ext;
> -	dsi_cfg->htotal = dsi_htotal;
> +	dsi_cfg->htotal = dsi_htotal + dsi_hfp_ext;
> +
> +	return 0;
> +}
> +
> +static int cdns_dsi_check_conf(struct cdns_dsi *dsi,
> +			       const struct drm_display_mode *mode,
> +			       struct cdns_dsi_cfg *dsi_cfg,
> +			       struct cdns_dphy_cfg *dphy_cfg,
> +			       bool mode_valid_check)
> +{
> +	struct cdns_dsi_output *output = &dsi->output;
> +	unsigned long dsi_hss_hsa_hse_hbp;
> +	unsigned int nlanes = output->dev->lanes;
> +	int ret;
> +
> +	ret = cdns_dsi_mode2cfg(dsi, mode, dsi_cfg, mode_valid_check);
> +	if (ret)
> +		return ret;
> +
> +	ret = cdns_dphy_validate(dsi, dsi_cfg, dphy_cfg, mode, mode_valid_check);
> +	if (ret)
> +		return ret;
> +
> +	dsi_hss_hsa_hse_hbp = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> +	if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> +		dsi_hss_hsa_hse_hbp += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
>  
>  	/*
>  	 * Make sure DPI(HFP) > DSI(HSS+HSA+HSE+HBP) to guarantee that the FIFO
>  	 * is empty before we start a receiving a new line on the DPI
>  	 * interface.
>  	 */
> -	if ((u64)dphy_cfg->lane_bps * dpi_hfp * nlanes <
> +	if ((u64)dphy_cfg->lane_bps * mode_to_dpi_hfp(mode) * nlanes <
>  	    (u64)dsi_hss_hsa_hse_hbp *
>  	    (mode_valid_check ? mode->clock : mode->crtc_clock) * 1000)
>  		return -EINVAL;
> @@ -842,7 +884,7 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>  	struct cdns_dsi_output *output = &dsi->output;
>  	struct cdns_dphy_cfg dphy_cfg;
>  	struct cdns_dsi_cfg dsi_cfg;
> -	int bpp, nlanes, ret;
> +	int bpp, ret;
>  
>  	/*
>  	 * VFP_DSI should be less than VFP_DPI and VFP_DSI should be at
> @@ -860,11 +902,9 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>  	if ((mode->hdisplay * bpp) % 32)
>  		return MODE_H_ILLEGAL;
>  
> -	nlanes = output->dev->lanes;
> -
> -	ret = cdns_dsi_mode2cfg(dsi, mode, &dsi_cfg, &dphy_cfg, true);
> +	ret = cdns_dsi_check_conf(dsi, mode, &dsi_cfg, &dphy_cfg, true);
>  	if (ret)
> -		return MODE_CLOCK_RANGE;
> +		return MODE_BAD;
>  
>  	return MODE_OK;
>  }
> @@ -990,7 +1030,7 @@ static void cdns_dsi_bridge_enable(struct drm_bridge *bridge)
>  	bpp = mipi_dsi_pixel_format_to_bpp(output->dev->format);
>  	nlanes = output->dev->lanes;
>  
> -	WARN_ON_ONCE(cdns_dsi_mode2cfg(dsi, mode, &dsi_cfg, &dphy_cfg, false));
> +	WARN_ON_ONCE(cdns_dsi_check_conf(dsi, mode, &dsi_cfg, &dphy_cfg, false));
>  
>  	cdns_dsi_hs_init(dsi, &dphy_cfg);
>  	cdns_dsi_init_link(dsi);
> -- 
> git-series 0.9.1

-- 
Sean Paul, Software Engineer, Google / Chromium OS