[PATCH RFC 5/5] drm/msm/dsi: Use MSM and DRM DSC helper methods

[Dmitry Baryshkov]

On 30/03/2023 02:18, Jessica Zhang wrote:
> Use MSM and DRM DSC helper methods.
> 
> Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 18 ++++++++++++------
>   1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 74d38f90398a..7419fe58a941 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -31,6 +31,7 @@
>   #include "msm_kms.h"
>   #include "msm_gem.h"
>   #include "phy/dsi_phy.h"
> +#include "disp/msm_dsc_helper.h"
>   
>   #define DSI_RESET_TOGGLE_DELAY_MS 20
>   
> @@ -841,14 +842,14 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
>   {
>   	struct drm_dsc_config *dsc = msm_host->dsc;
>   	u32 reg, reg_ctrl, reg_ctrl2;
> -	u32 slice_per_intf, total_bytes_per_intf;
> +	u32 slice_per_intf;
>   	u32 pkt_per_line;
>   	u32 eol_byte_num;
>   
>   	/* first calculate dsc parameters and then program
>   	 * compress mode registers
>   	 */
> -	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
> +	slice_per_intf = msm_dsc_get_slice_per_intf(dsc, hdisplay);

This looks good

>   
>   	/*
>   	 * If slice_count is greater than slice_per_intf
> @@ -858,10 +859,10 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
>   	if (dsc->slice_count > slice_per_intf)
>   		dsc->slice_count = 1;
>   
> -	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
> +	eol_byte_num = msm_dsc_get_eol_byte_num(msm_host->dsc, hdisplay,
> +			dsi_get_bpp(msm_host->format));
>   
> -	eol_byte_num = total_bytes_per_intf % 3;
> -	pkt_per_line = slice_per_intf / dsc->slice_count;
> +	pkt_per_line = slice_per_intf / MSM_DSC_SLICE_PER_PKT;

And for these values the result is definitely changed. Separate patch & 
description please. Just in case, "values per downstream kernel" is not 
a proper description for such changes.

>   
>   	if (is_cmd_mode) /* packet data type */
>   		reg = DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE);
> @@ -911,6 +912,11 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
>   
>   	DBG("");
>   
> +	if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO)
> +		/* Default widebus_en to false for now. */
> +		hdisplay = msm_dsc_get_pclk_per_line(msm_host->dsc, mode->hdisplay,
> +				dsi_get_bpp(msm_host->format));
> +

This is definitely something new and thus should probably go into a 
separate patch and be described. Also I'm not sure how does that 
interact with the hdisplay-related calculations below, under the if(dsc) 
clause.

>   	/*
>   	 * For bonded DSI mode, the current DRM mode has
>   	 * the complete width of the panel. Since, the complete
> @@ -1759,7 +1765,7 @@ static int dsi_populate_dsc_params(struct msm_dsi_host *msm_host, struct drm_dsc
>   		return ret;
>   	}
>   
> -	dsc->initial_scale_value = 32;
> +	dsc->initial_scale_value = drm_dsc_calculate_initial_scale_value(dsc);

This is fine, we only support 8bpp where these values match.

>   	dsc->line_buf_depth = dsc->bits_per_component + 1;
>   
>   	return drm_dsc_compute_rc_parameters(dsc);
> 

-- 
With best wishes
Dmitry