Re: [PATCH 2/2] drm/i915/BXT: Get pipe conf from the port registers

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 30 Mar 2016, Ramalingam C <ramalingam.c@intel.com> wrote:
> At BXT DSI, PIPE registers are inactive. So we can't get the
> PIPE's mode parameters from them. The possible option is
> retriving them from the PORT registers.
>
> The required changes are added for BXT in intel_dsi_get_config
> (encoder->get_config).
>
> v2: Addressed the Jani's comments
>     -removed the redundant call to encoder->get_config
>     -read bpp from port register
>     -removed retrival of src_size from encoder->get_config
>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> Signed-off-by: Uma Shankar <uma.shankar@intel.com>
> ---
> Previously reviewed at https://patchwork.freedesktop.org/patch/75301/
>
>  drivers/gpu/drm/i915/intel_dsi.c |   99 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 99 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 0de74e1..2117187 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -46,6 +46,11 @@ static const struct {
>  	},
>  };
>  
> +enum mipi_dsi_pixel_format reg_to_pixel_format(u32 fmt)
> +{
> +	return pixel_format_from_vbt(fmt);
> +}
> +

See reply to preceding patch.

>  static void wait_for_dsi_fifo_empty(struct intel_dsi *intel_dsi, enum port port)
>  {
>  	struct drm_encoder *encoder = &intel_dsi->base.base;
> @@ -740,14 +745,108 @@ out_put_power:
>  	return active;
>  }
>  
> +/* return pixels equvalent to txbyteclkhs */
> +static u16 pixels_from_txbyteclkhs(u16 clk_hs, int bpp, int lane_count,
> +		       u16 burst_mode_ratio)
> +{
> +	return DIV_ROUND_UP((clk_hs * lane_count * 8 * 100),
> +						(bpp * burst_mode_ratio));
> +}
> +
> +static void bxt_dsi_get_pipe_config(struct intel_encoder *encoder,
> +				 struct intel_crtc_state *pipe_config)
> +{
> +	struct drm_device *dev = encoder->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_display_mode *adjusted_mode =
> +					&pipe_config->base.adjusted_mode;
> +	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> +	unsigned int lane_count = intel_dsi->lane_count;
> +	unsigned int bpp, fmt;
> +	enum port port;
> +	u16 hactive, hfp, hsync, hbp, vfp, vsync, vbp;
> +
> +	/*
> +	 * Atleast one port is active as encoder->get_config called only if
> +	 * encoder->get_hw_state() returns true.
> +	 */
> +	for_each_dsi_port(port, intel_dsi->ports) {
> +		if (!(I915_READ(BXT_MIPI_PORT_CTRL(port)) & DPI_ENABLE))
> +			continue;
> +		break;

In other words,

	if (I915_READ(BXT_MIPI_PORT_CTRL(port)) & DPI_ENABLE)
		break;


> +	}
> +
> +	fmt = I915_READ(MIPI_DSI_FUNC_PRG(port)) & VID_MODE_FORMAT_MASK;
> +	pipe_config->pipe_bpp = reg_to_pixel_format(fmt);
> +
> +	bpp = mipi_dsi_pixel_format_to_bpp(pipe_config->pipe_bpp);
> +
> +	/* In terms of pixels */
> +	adjusted_mode->crtc_hdisplay =
> +				I915_READ(BXT_MIPI_TRANS_HACTIVE(port));
> +	adjusted_mode->crtc_vdisplay =
> +				I915_READ(BXT_MIPI_TRANS_VACTIVE(port));
> +	adjusted_mode->crtc_vtotal =
> +				I915_READ(BXT_MIPI_TRANS_VTOTAL(port));
> +
> +	hactive = adjusted_mode->crtc_hdisplay;
> +	hfp = I915_READ(MIPI_HFP_COUNT(port));
> +
> +	/*
> +	 * meaningful for video mode non-burst sync pulse mode only,
> +	 * can be zero for non-burst sync events and burst modes
> +	 */
> +	hsync = I915_READ(MIPI_HSYNC_PADDING_COUNT(port));
> +	hbp = I915_READ(MIPI_HBP_COUNT(port));
> +
> +	/* horizontal values are in terms of high speed byte clock */
> +	hfp = pixels_from_txbyteclkhs(hfp, bpp, lane_count,
> +					intel_dsi->burst_mode_ratio);
> +	hsync = pixels_from_txbyteclkhs(hsync, bpp, lane_count,
> +					intel_dsi->burst_mode_ratio);
> +	hbp = pixels_from_txbyteclkhs(hbp, bpp, lane_count,
> +					intel_dsi->burst_mode_ratio);
> +
> +	if (intel_dsi->dual_link) {
> +		hfp *= 2;
> +		hsync *= 2;
> +		hbp *= 2;
> +	}
> +
> +	/* vertical values are in terms of lines */
> +	vfp = I915_READ(MIPI_VFP_COUNT(port));
> +	vsync = I915_READ(MIPI_VSYNC_PADDING_COUNT(port));
> +	vbp = I915_READ(MIPI_VBP_COUNT(port));
> +
> +	adjusted_mode->crtc_htotal = hactive + hfp + hsync + hbp;
> +	adjusted_mode->crtc_hsync_start =
> +				hfp + adjusted_mode->crtc_hdisplay;
> +	adjusted_mode->crtc_hsync_end =
> +				hsync + adjusted_mode->crtc_hsync_start;
> +	adjusted_mode->crtc_hblank_start = adjusted_mode->crtc_hdisplay;
> +	adjusted_mode->crtc_hblank_end = adjusted_mode->crtc_htotal;
> +
> +	adjusted_mode->crtc_vsync_start =
> +				vfp + adjusted_mode->crtc_vdisplay;
> +	adjusted_mode->crtc_vsync_end =
> +				vsync + adjusted_mode->crtc_vsync_start;
> +	adjusted_mode->crtc_vblank_start = adjusted_mode->crtc_vdisplay;
> +	adjusted_mode->crtc_vblank_end = adjusted_mode->crtc_vtotal;

As I suggested on IRC, to make progress please keep everything that we
can calculate accurately (and hence get no warnings about the diff for
them) and leave out all that is not accurate.

We need to get back to them too, but currently there seems to be
disagreement on what is the best/feasible/possible option.

BR,
Jani.


> +}
> +
> +
>  static void intel_dsi_get_config(struct intel_encoder *encoder,
>  				 struct intel_crtc_state *pipe_config)
>  {
> +	struct drm_device *dev = encoder->base.dev;
>  	u32 pclk;
>  	DRM_DEBUG_KMS("\n");
>  
>  	pipe_config->has_dsi_encoder = true;
>  
> +	if (IS_BROXTON(dev))
> +		bxt_dsi_get_pipe_config(encoder, pipe_config);
> +
>  	/*
>  	 * DPLL_MD is not used in case of DSI, reading will get some default value
>  	 * set dpll_md = 0

-- 
Jani Nikula, Intel Open Source Technology Center
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