drm/amd/display: DCHUB requestors numbers for Navi.

[Why]
The DCHub arbiter has a mechanism to dynamically rate limit the DCHub
request stream to the fabric. If the memory controller is fully utilized
and the DCHub requestors are well ahead of their amortized schedule,
then it is safe to prevent the next winner from being committed and sent
to the fabric. The utilization of the memory controller is approximated
by ensuring that the number of outstanding requests is greater than a
threshold specified by the ARB_MIN_REQ_OUTSTANDING. To determine that
the DCHub requestors are well ahead of the amortized schedule, the slack
of the next winner is compared with the ARB_SAT_LEVEL in DLG RefClk
cycles.

[How]
The recommended settings to enable thise dynamic limiting for Navi is
180 requests.
Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubbub.c

@@ -493,6 +493,28 @@ void hubbub2_get_dchub_ref_freq(struct hubbub *hubbub,
 	}
 }
 
+static void hubbub2_program_watermarks(
+		struct hubbub *hubbub,
+		struct dcn_watermark_set *watermarks,
+		unsigned int refclk_mhz,
+		bool safe_to_lower)
+{
+	struct dcn20_hubbub *hubbub1 = TO_DCN20_HUBBUB(hubbub);
+	/*
+	 * Need to clamp to max of the register values (i.e. no wrap)
+	 * for dcn1, all wm registers are 21-bit wide
+	 */
+	hubbub1_program_urgent_watermarks(hubbub, watermarks, refclk_mhz, safe_to_lower);
+	hubbub1_program_stutter_watermarks(hubbub, watermarks, refclk_mhz, safe_to_lower);
+	hubbub1_program_pstate_watermarks(hubbub, watermarks, refclk_mhz, safe_to_lower);
+
+	REG_SET(DCHUBBUB_ARB_SAT_LEVEL, 0,
+			DCHUBBUB_ARB_SAT_LEVEL, 60 * refclk_mhz);
+	REG_UPDATE(DCHUBBUB_ARB_DF_REQ_OUTSTAND, DCHUBBUB_ARB_MIN_REQ_OUTSTAND, 180);
+
+	hubbub1_allow_self_refresh_control(hubbub, !hubbub->ctx->dc->debug.disable_stutter);
+}
+
 static const struct hubbub_funcs hubbub2_funcs = {
 	.update_dchub = hubbub2_update_dchub,
 	.init_dchub = hubbub2_init_dchub,
@@ -502,7 +524,7 @@ static const struct hubbub_funcs hubbub2_funcs = {
 	.get_dcc_compression_cap = hubbub2_get_dcc_compression_cap,
 	.wm_read_state = hubbub2_wm_read_state,
 	.get_dchub_ref_freq = hubbub2_get_dchub_ref_freq,
-	.program_watermarks = hubbub1_program_watermarks,
+	.program_watermarks = hubbub2_program_watermarks,
 };
 
 void hubbub2_construct(struct dcn20_hubbub *hubbub,