drm/amd/display: add method to check for supported range

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 58 insertions, 6 deletions

diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index 5e12e463c06a..4af73a72b9a9 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -168,6 +168,21 @@ static unsigned int calc_v_total_from_duration(
         return v_total;
 }
 
+static unsigned long long calc_nominal_field_rate(const struct dc_stream_state *stream)
+{
+        unsigned long long nominal_field_rate_in_uhz = 0;
+
+        /* Calculate nominal field rate for stream */
+        nominal_field_rate_in_uhz = stream->timing.pix_clk_khz;
+        nominal_field_rate_in_uhz *= 1000ULL * 1000ULL * 1000ULL;
+        nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
+                                                stream->timing.h_total);
+        nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
+                                                stream->timing.v_total);
+
+        return nominal_field_rate_in_uhz;
+}
+
 static void update_v_total_for_static_ramp(
                 struct core_freesync *core_freesync,
                 const struct dc_stream_state *stream,
@@ -623,12 +638,7 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
         core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
 
         /* Calculate nominal field rate for stream */
-        nominal_field_rate_in_uhz = stream->timing.pix_clk_khz;
-        nominal_field_rate_in_uhz *= 1000ULL * 1000ULL * 1000ULL;
-        nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
-                                                stream->timing.h_total);
-        nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
-                                                stream->timing.v_total);
+        nominal_field_rate_in_uhz = calc_nominal_field_rate(stream);
 
         min_refresh_in_uhz = in_config->min_refresh_in_uhz;
         max_refresh_in_uhz = in_config->max_refresh_in_uhz;
@@ -878,3 +888,45 @@ void mod_freesync_get_settings(struct mod_freesync *mod_freesync,
         }
 }
 
+bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
+                const struct dc_stream_state *stream,
+                uint32_t min_refresh_cap_in_uhz,
+                uint32_t max_refresh_cap_in_uhz,
+                uint32_t min_refresh_request_in_uhz,
+                uint32_t max_refresh_request_in_uhz)
+{
+        /* Calculate nominal field rate for stream */
+        unsigned long long nominal_field_rate_in_uhz =
+                        calc_nominal_field_rate(stream);
+
+        // Check nominal is within range
+        if (nominal_field_rate_in_uhz > max_refresh_cap_in_uhz ||
+                nominal_field_rate_in_uhz < min_refresh_cap_in_uhz)
+                return false;
+
+        // If nominal is less than max, limit the max allowed refresh rate
+        if (nominal_field_rate_in_uhz < max_refresh_cap_in_uhz)
+                max_refresh_cap_in_uhz = nominal_field_rate_in_uhz;
+
+        // Don't allow min > max
+        if (min_refresh_request_in_uhz > max_refresh_request_in_uhz)
+                return false;
+
+        // Check min is within range
+        if (min_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
+                min_refresh_request_in_uhz < min_refresh_cap_in_uhz)
+                return false;
+
+        // Check max is within range
+        if (max_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
+                max_refresh_request_in_uhz < min_refresh_cap_in_uhz)
+                return false;
+
+        // For variable range, check for at least 10 Hz range
+        if ((max_refresh_request_in_uhz != min_refresh_request_in_uhz) &&
+                (max_refresh_request_in_uhz - min_refresh_request_in_uhz < 10000000))
+                return false;
+
+        return true;
+}
+