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)
Reviewed-by: Imre Deak <imre.d...@intel.com>
Signed-off-by: Arun R Murthy <arun.r.mur...@intel.com>
---
drivers/gpu/drm/display/drm_dp_helper.c | 52 +++++++++++++++++++++------------
include/drm/display/drm_dp_helper.h | 2 ++
2 files changed, 36 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
b/drivers/gpu/drm/display/drm_dp_helper.c
index
57828f2b7b5a0582ca4a6f2a9be2d5909fe8ad24..56c7e3318f01079c3bde492a21c76ed37e9724ca
100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -4393,8 +4393,9 @@ 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;
@@ -4402,22 +4403,42 @@ 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
*
@@ -4431,7 +4452,7 @@ 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().
@@ -4486,15 +4507,10 @@ 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
d9614e2c89397536f44bb7258e894628ae1dccc9..7b19192c70313d66dce1b7ba40dd59c14f80a182
100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -971,5 +971,7 @@ 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_ */
--
2.25.1
