From: Arun R Murthy Date: Thu, 24 Apr 2025 15:15:14 +0000 (+0530) Subject: drm/display/dp: Export fn to calculate link symbol cycles X-Git-Tag: v6.16-rc1~144^2~12^2~31 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d585426a6538a717f55a1bb0b614d465bd03805;p=thirdparty%2Flinux.git drm/display/dp: Export fn to calculate link symbol cycles Unify the function to calculate the link symbol cycles for both dsc and non-dsc case and export the function so that it can be used in the respective platform display drivers for other calculations. v2: unify the fn for both dsc and non-dsc case (Imre) v3: rename drm_dp_link_symbol_cycles to drm_dp_link_data_symbol_cycles retain slice_eoc_cycles as is (Imre) v4: Expose only drm_dp_link_symbol_cycles() (Imre) v6: Add slice pixels which was removed unknowingly (Vinod) Signed-off-by: Arun R Murthy Reviewed-by: Imre Deak Reviewed-by: Vinod Govindapillai Acked-by: Maarten Lankhorst Signed-off-by: Imre Deak Link: https://lore.kernel.org/r/20250424-hblank-v7-1-8b002f1506cc@intel.com --- diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index f5c596234729d..8f774221eeb3f 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -4324,8 +4324,9 @@ EXPORT_SYMBOL(drm_panel_dp_aux_backlight); #endif /* See DP Standard v2.1 2.6.4.4.1.1, 2.8.4.4, 2.8.7 */ -static int drm_dp_link_symbol_cycles(int lane_count, int pixels, int bpp_x16, - int symbol_size, bool is_mst) +static int drm_dp_link_data_symbol_cycles(int lane_count, int pixels, + int bpp_x16, int symbol_size, + bool is_mst) { int cycles = DIV_ROUND_UP(pixels * bpp_x16, 16 * symbol_size * lane_count); int align = is_mst ? 4 / lane_count : 1; @@ -4333,22 +4334,42 @@ static int drm_dp_link_symbol_cycles(int lane_count, int pixels, int bpp_x16, return ALIGN(cycles, align); } -static int drm_dp_link_dsc_symbol_cycles(int lane_count, int pixels, int slice_count, - int bpp_x16, int symbol_size, bool is_mst) +/** + * drm_dp_link_symbol_cycles - calculate the link symbol count with/without dsc + * @lane_count: DP link lane count + * @pixels: number of pixels in a scanline + * @dsc_slice_count: number of slices for DSC or '0' for non-DSC + * @bpp_x16: bits per pixel in .4 binary fixed format + * @symbol_size: DP symbol size + * @is_mst: %true for MST and %false for SST + * + * Calculate the link symbol cycles for both DSC (@dsc_slice_count !=0) and + * non-DSC case (@dsc_slice_count == 0) and return the count. + */ +int drm_dp_link_symbol_cycles(int lane_count, int pixels, int dsc_slice_count, + int bpp_x16, int symbol_size, bool is_mst) { + int slice_count = dsc_slice_count ? : 1; int slice_pixels = DIV_ROUND_UP(pixels, slice_count); - int slice_data_cycles = drm_dp_link_symbol_cycles(lane_count, slice_pixels, - bpp_x16, symbol_size, is_mst); - int slice_eoc_cycles = is_mst ? 4 / lane_count : 1; + int slice_data_cycles = drm_dp_link_data_symbol_cycles(lane_count, + slice_pixels, + bpp_x16, + symbol_size, + is_mst); + int slice_eoc_cycles = 0; + + if (dsc_slice_count) + slice_eoc_cycles = is_mst ? 4 / lane_count : 1; return slice_count * (slice_data_cycles + slice_eoc_cycles); } +EXPORT_SYMBOL(drm_dp_link_symbol_cycles); /** * drm_dp_bw_overhead - Calculate the BW overhead of a DP link stream * @lane_count: DP link lane count * @hactive: pixel count of the active period in one scanline of the stream - * @dsc_slice_count: DSC slice count if @flags/DRM_DP_LINK_BW_OVERHEAD_DSC is set + * @dsc_slice_count: number of slices for DSC or '0' for non-DSC * @bpp_x16: bits per pixel in .4 binary fixed point * @flags: DRM_DP_OVERHEAD_x flags * @@ -4362,7 +4383,7 @@ static int drm_dp_link_dsc_symbol_cycles(int lane_count, int pixels, int slice_c * as well as the stream's * - @hactive timing * - @bpp_x16 color depth - * - compression mode (@flags / %DRM_DP_OVERHEAD_DSC). + * - compression mode (@dsc_slice_count != 0) * Note that this overhead doesn't account for the 8b/10b, 128b/132b * channel coding efficiency, for that see * @drm_dp_link_bw_channel_coding_efficiency(). @@ -4417,15 +4438,10 @@ int drm_dp_bw_overhead(int lane_count, int hactive, WARN_ON((flags & DRM_DP_BW_OVERHEAD_UHBR) && (flags & DRM_DP_BW_OVERHEAD_FEC)); - if (flags & DRM_DP_BW_OVERHEAD_DSC) - symbol_cycles = drm_dp_link_dsc_symbol_cycles(lane_count, hactive, - dsc_slice_count, - bpp_x16, symbol_size, - is_mst); - else - symbol_cycles = drm_dp_link_symbol_cycles(lane_count, hactive, - bpp_x16, symbol_size, - is_mst); + symbol_cycles = drm_dp_link_symbol_cycles(lane_count, hactive, + dsc_slice_count, + bpp_x16, symbol_size, + is_mst); return DIV_ROUND_UP_ULL(mul_u32_u32(symbol_cycles * symbol_size * lane_count, overhead * 16), diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h index 89a34dff85a4e..36ca21d6a3997 100644 --- a/include/drm/display/drm_dp_helper.h +++ b/include/drm/display/drm_dp_helper.h @@ -879,5 +879,7 @@ int drm_dp_bw_channel_coding_efficiency(bool is_uhbr); int drm_dp_max_dprx_data_rate(int max_link_rate, int max_lanes); ssize_t drm_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc, struct dp_sdp *sdp); +int drm_dp_link_symbol_cycles(int lane_count, int pixels, int dsc_slice_count, + int bpp_x16, int symbol_size, bool is_mst); #endif /* _DRM_DP_HELPER_H_ */