[RFC v2 4/5] drm/hdmi21: Add support for DFM calculation with DSC
Vandita Kulkarni
vandita.kulkarni at intel.com
Mon Feb 14 02:03:56 UTC 2022
From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Add helper functions for calculating FRL capacity and DFM
requirements with given compressed bpp.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
---
drivers/gpu/drm/drm_frl_dfm_helper.c | 297 +++++++++++++++++++++++++++
include/drm/drm_frl_dfm_helper.h | 3 +
2 files changed, 300 insertions(+)
diff --git a/drivers/gpu/drm/drm_frl_dfm_helper.c b/drivers/gpu/drm/drm_frl_dfm_helper.c
index b8f4f8ee50d3..9eb91dd4e21e 100644
--- a/drivers/gpu/drm/drm_frl_dfm_helper.c
+++ b/drivers/gpu/drm/drm_frl_dfm_helper.c
@@ -555,3 +555,300 @@ drm_frl_dfm_nondsc_requirement_met(struct drm_hdmi_frl_dfm *frl_dfm)
return false;
}
EXPORT_SYMBOL(drm_frl_dfm_nondsc_requirement_met);
+
+/* DSC DFM functions */
+/* Get FRL Available characters */
+static unsigned int
+drm_get_frl_available_chars(unsigned int overhead_max, unsigned int cfrl_line)
+{
+ unsigned int frl_char_avlb = ((EFFICIENCY_MULTIPLIER - overhead_max) * cfrl_line);
+
+ return frl_char_avlb / EFFICIENCY_MULTIPLIER;
+}
+
+/* Get required no. of tribytes during HCActive */
+static unsigned int
+drm_get_frl_hcactive_tb_target(unsigned int dsc_bpp_x16, unsigned int slice_width, unsigned int num_slices)
+{
+ unsigned int bytes_target;
+
+ bytes_target = num_slices * DIV_ROUND_UP(dsc_bpp_x16 * slice_width,
+ 8 * BPP_MULTIPLIER);
+
+ return DIV_ROUND_UP(bytes_target, 3);
+}
+
+/* Get required no. of tribytes (estimate1) during HCBlank */
+static unsigned int
+drm_get_frl_hcblank_tb_est1_target(unsigned int hcactive_target_tb,
+ unsigned int hactive, unsigned int hblank)
+{
+ return DIV_ROUND_UP(hcactive_target_tb * hblank, hactive);
+}
+
+/* Get required no. of tribytes during HCBlank */
+static unsigned int
+drm_get_frl_hcblank_tb_target(unsigned int hcactive_target_tb, unsigned int hactive, unsigned int hblank,
+ unsigned int hcblank_audio_min, unsigned int cfrl_available)
+{
+ unsigned int hcblank_target_tb1 = drm_get_frl_hcblank_tb_est1_target(hcactive_target_tb,
+ hactive, hblank);
+ unsigned int hcblank_target_tb2 = max(hcblank_target_tb1, hcblank_audio_min);
+
+ return 4 * (min(hcblank_target_tb2,
+ (2 * cfrl_available - 3 * hcactive_target_tb) / 2) / 4);
+}
+
+/* Get the avg no of tribytes sent per sec (Kbps) */
+static unsigned int
+drm_frl_dsc_get_ftb_avg(unsigned int hcactive_target_tb, unsigned int hcblank_target_tb,
+ unsigned int hactive, unsigned int hblank,
+ unsigned int fpixelclock_max_khz)
+{
+ return (hcactive_target_tb + hcblank_target_tb) * (fpixelclock_max_khz / (hactive + hblank));
+}
+
+/* Time to send Active tribytes in nanoseconds */
+static unsigned int
+drm_frl_dsc_get_tactive_ref_ns(unsigned int line_time_ns, unsigned int hactive, unsigned int hblank)
+{
+ return (line_time_ns * hactive) / (hactive + hblank);
+}
+
+/* Time to send Blanking tribytes in nanoseconds */
+static unsigned int
+drm_frl_dsc_get_tblank_ref_ns(unsigned int line_time_ns, unsigned int hactive, unsigned int hblank)
+{
+ return (line_time_ns * hblank) / (hactive + hblank);
+}
+
+/* Get time to send all tribytes in hcactive region in nsec*/
+static unsigned int
+drm_frl_dsc_tactive_target_ns(unsigned int frl_lanes, unsigned int hcactive_target_tb, unsigned int ftb_avg_k,
+ unsigned int min_frl_char_rate_k, unsigned int overhead_max)
+{
+ unsigned int avg_tribyte_time_ns, tribyte_time_ns;
+ unsigned int num_chars_hcactive;
+ unsigned int frl_char_rate_k;
+
+ /* Avg time to transmit all active region tribytes */
+ avg_tribyte_time_ns = (hcactive_target_tb * FRL_TIMING_NS_MULTIPLIER) /
+ (ftb_avg_k * 1000);
+
+ /*
+ * 2 bytes in active region = 1 FRL characters
+ * 1 Tribyte in active region = 3/2 FRL characters
+ */
+
+ num_chars_hcactive = (hcactive_target_tb * 3) / 2;
+
+ /*
+ * FRL rate = lanes * frl character rate
+ * But actual bandwidth wil be less, due to FRL limitations so account
+ * for the overhead involved.
+ * FRL rate with overhead = FRL rate * (100 - overhead %) / 100
+ */
+ frl_char_rate_k = frl_lanes * min_frl_char_rate_k;
+ frl_char_rate_k = (frl_char_rate_k * (EFFICIENCY_MULTIPLIER - overhead_max)) /
+ EFFICIENCY_MULTIPLIER;
+
+ /* Time to transmit all characters with FRL limitations */
+ tribyte_time_ns = (num_chars_hcactive * FRL_TIMING_NS_MULTIPLIER) /
+ frl_char_rate_k * 1000;
+
+ return max(avg_tribyte_time_ns, tribyte_time_ns);
+}
+
+/* Get no. of tri bytes borrowed with DSC enabled */
+static unsigned int
+drm_frl_get_dsc_tri_bytes_borrowed(unsigned int tactive_target_ns, unsigned int ftb_avg_k,
+ unsigned int hcactive_target_tb)
+{
+ return (tactive_target_ns * FRL_TIMING_NS_MULTIPLIER * ftb_avg_k * 1000) -
+ hcactive_target_tb;
+}
+
+/* Get TBdelta */
+static unsigned int
+drm_frl_get_dsc_tri_bytes_delta(unsigned int tactive_target_ns, unsigned int tactive_ref_ns,
+ unsigned int hcactive_target_tb, unsigned int ftb_avg_k,
+ unsigned int hactive, unsigned int hblank, unsigned int line_time_ns)
+{
+ unsigned int tb_delta_limit;
+ unsigned int tblank_target_ns = line_time_ns - tactive_target_ns;
+ unsigned int tblank_ref_ns = line_time_ns - tactive_ref_ns;
+ unsigned int hcblank_target_tb1 = drm_get_frl_hcblank_tb_est1_target(hcactive_target_tb,
+ hactive, hblank);
+
+ if (tblank_ref_ns < tblank_target_ns) {
+ tb_delta_limit = (((tactive_ref_ns * FRL_TIMING_NS_MULTIPLIER) - (hcactive_target_tb / (ftb_avg_k * 1000))) *
+ (hcactive_target_tb + hcblank_target_tb1)) /
+ (line_time_ns * FRL_TIMING_NS_MULTIPLIER);
+ } else {
+ unsigned int _tb_delta_ns;
+
+ if (tactive_target_ns > tactive_ref_ns)
+ _tb_delta_ns = tactive_target_ns - tactive_ref_ns;
+ else
+ _tb_delta_ns = tactive_ref_ns - tactive_target_ns;
+ tb_delta_limit = (_tb_delta_ns * (hcactive_target_tb + hcblank_target_tb1)) / line_time_ns;
+ }
+
+ return tb_delta_limit;
+}
+
+/* Compute hcactive and hcblank tribytes for given dsc bpp setting */
+static void
+drm_frl_dfm_dsc_compute_tribytes(struct drm_hdmi_frl_dfm *frl_dfm)
+{
+ unsigned int hcactive_target_tb;
+ unsigned int hcblank_target_tb;
+ unsigned int cfrl_available;
+ unsigned int num_slices;
+
+ /* Assert for slice width ?*/
+ if (!frl_dfm->config.slice_width)
+ return;
+
+ num_slices = DIV_ROUND_UP(frl_dfm->config.hactive, frl_dfm->config.slice_width);
+
+ hcactive_target_tb = drm_get_frl_hcactive_tb_target(frl_dfm->config.target_bpp_16,
+ frl_dfm->config.slice_width,
+ num_slices);
+
+ cfrl_available =
+ drm_get_frl_available_chars(frl_dfm->params.overhead_max,
+ frl_dfm->params.cfrl_line);
+
+ hcblank_target_tb =
+ drm_get_frl_hcblank_tb_target(hcactive_target_tb,
+ frl_dfm->config.hactive,
+ frl_dfm->config.hblank,
+ frl_dfm->params.hblank_audio_min,
+ cfrl_available);
+
+ frl_dfm->params.hcactive_target = hcactive_target_tb;
+ frl_dfm->params.hcblank_target = hcblank_target_tb;
+}
+
+/* Check if audio supported with given dsc bpp and frl bandwidth */
+static bool
+drm_frl_dfm_dsc_audio_supported(struct drm_hdmi_frl_dfm *frl_dfm)
+{
+ return frl_dfm->params.hcblank_target < frl_dfm->params.hblank_audio_min;
+}
+
+/* Is DFM timing requirement is met with DSC */
+static
+bool drm_frl_dfm_dsc_is_timing_req_met(struct drm_hdmi_frl_dfm *frl_dfm)
+{
+ unsigned int ftb_avg_k;
+ unsigned int tactive_ref_ns, tblank_ref_ns, tactive_target_ns, tblank_target_ns;
+ unsigned int tb_borrowed, tb_delta, tb_worst;
+
+ ftb_avg_k = drm_frl_dsc_get_ftb_avg(frl_dfm->params.hcactive_target,
+ frl_dfm->params.hcblank_target,
+ frl_dfm->config.hactive,
+ frl_dfm->config.hblank,
+ frl_dfm->params.pixel_clock_max_khz);
+
+ tactive_ref_ns = drm_frl_dsc_get_tactive_ref_ns(frl_dfm->params.line_time_ns,
+ frl_dfm->config.hactive,
+ frl_dfm->config.hblank);
+
+ tblank_ref_ns = drm_frl_dsc_get_tblank_ref_ns(frl_dfm->params.line_time_ns,
+ frl_dfm->config.hactive,
+ frl_dfm->config.hblank);
+
+ tactive_target_ns = drm_frl_dsc_tactive_target_ns(frl_dfm->config.lanes,
+ frl_dfm->params.hcactive_target,
+ ftb_avg_k,
+ frl_dfm->params.char_rate_min_kbps,
+ frl_dfm->params.overhead_max);
+
+ tblank_target_ns = frl_dfm->params.line_time_ns - tactive_target_ns;
+
+ tb_borrowed = drm_frl_get_dsc_tri_bytes_borrowed(tactive_target_ns,
+ ftb_avg_k,
+ frl_dfm->params.hcactive_target);
+
+ tb_delta = drm_frl_get_dsc_tri_bytes_delta(tactive_target_ns,
+ tactive_ref_ns,
+ frl_dfm->params.hcactive_target,
+ ftb_avg_k,
+ frl_dfm->config.hactive,
+ frl_dfm->config.hblank,
+ frl_dfm->params.line_time_ns);
+
+ tb_worst = max(tb_borrowed, tb_delta);
+ if (tb_worst > TB_BORROWED_MAX)
+ return false;
+
+ frl_dfm->params.ftb_avg_k = ftb_avg_k;
+ frl_dfm->params.tb_borrowed = tb_borrowed;
+
+ return true;
+}
+
+/* Check Utilization constraint with DSC */
+static bool
+drm_frl_dsc_check_utilization(struct drm_hdmi_frl_dfm *frl_dfm)
+{
+ unsigned int hcactive_target_tb = frl_dfm->params.hcactive_target;
+ unsigned int hcblank_target_tb = frl_dfm->params.hcblank_target;
+ unsigned int frl_char_per_line = frl_dfm->params.cfrl_line;
+ unsigned int overhead_max = frl_dfm->params.overhead_max;
+ unsigned int actual_frl_char_payload;
+ unsigned int utilization;
+ unsigned int utilization_with_overhead;
+
+ /* Note:
+ * 1 FRL characters per 2 bytes in active period
+ * 1 FRL char per byte in Blanking period
+ */
+ actual_frl_char_payload = DIV_ROUND_UP(3 * hcactive_target_tb, 2) +
+ hcblank_target_tb;
+
+ utilization = (actual_frl_char_payload * EFFICIENCY_MULTIPLIER) /
+ frl_char_per_line;
+
+ /*
+ * Utilization with overhead = utlization% +overhead %
+ * should be less than 100%
+ */
+ utilization_with_overhead = utilization + overhead_max;
+ if (utilization_with_overhead > EFFICIENCY_MULTIPLIER)
+ return false;
+
+ return false;
+}
+
+/*
+ * drm_frl_fm_dsc_requirement_met : Check if FRL DFM requirements are met with
+ * the given bpp.
+ * @frl_dfm: dfm structure
+ *
+ * Returns true if the frl dfm requirements are met, else returns false.
+ */
+bool drm_frl_dfm_dsc_requirement_met(struct drm_hdmi_frl_dfm *frl_dfm)
+{
+ if (!frl_dfm->config.slice_width || !frl_dfm->config.target_bpp_16)
+ return false;
+
+ drm_frl_dfm_compute_max_frl_link_overhead(frl_dfm);
+ drm_frl_dfm_compute_link_characteristics(frl_dfm);
+ drm_frl_dfm_compute_audio_hblank_min(frl_dfm);
+ drm_frl_dfm_dsc_compute_tribytes(frl_dfm);
+
+ if (!drm_frl_dfm_dsc_audio_supported(frl_dfm))
+ return false;
+
+ if (!drm_frl_dfm_dsc_is_timing_req_met(frl_dfm))
+ return false;
+
+ if (!drm_frl_dsc_check_utilization(frl_dfm))
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL(drm_frl_dfm_dsc_requirement_met);
diff --git a/include/drm/drm_frl_dfm_helper.h b/include/drm/drm_frl_dfm_helper.h
index 67f9caebd903..a6dc2479683b 100644
--- a/include/drm/drm_frl_dfm_helper.h
+++ b/include/drm/drm_frl_dfm_helper.h
@@ -123,4 +123,7 @@ struct drm_hdmi_frl_dfm {
bool drm_frl_dfm_nondsc_requirement_met(struct drm_hdmi_frl_dfm *frl_dfm);
+bool
+drm_frl_dfm_dsc_requirement_met(struct drm_hdmi_frl_dfm *frl_dfm);
+
#endif
--
2.32.0
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