drm/amd/display: FCLK P-state support updates

[Why]
Previously we used to send FCLK P-state enable messages upon each call
to update_clocks based on dml output. This resulted in increased message
transactions between DC and PMFW.

[How]
Update the code to check safe_to_lower status and send the message based
on dml input only on boot. This reduces message transactions. Also
remove other unwanted code based on current code status.

Signed-off-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr.c

@@ -284,7 +284,7 @@ static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
 	bool dpp_clock_lowered = false;
 	struct dmcu *dmcu = clk_mgr_base->ctx->dc->res_pool->dmcu;
 	bool force_reset = false;
-	bool update_uclk = false;
+	bool update_uclk = false, update_fclk = false;
 	bool p_state_change_support;
 	bool fclk_p_state_change_support;
 	int total_plane_count;
@@ -371,14 +371,17 @@ static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
 			update_uclk = true;
 		}
 
+		/* Always update saved value, even if new value not set due to P-State switching unsupported. Also check safe_to_lower for FCLK */
+		if (safe_to_lower && (clk_mgr_base->clks.fclk_p_state_change_support != clk_mgr_base->clks.fclk_prev_p_state_change_support)) {
+			update_fclk = true;
+		}
+
 		/* set UCLK to requested value if P-State switching is supported, or to re-enable P-State switching */
 		if (clk_mgr_base->clks.p_state_change_support &&
 				(update_uclk || !clk_mgr_base->clks.prev_p_state_change_support))
 			dcn30_smu_set_hard_min_by_freq(clk_mgr, PPCLK_UCLK, khz_to_mhz_ceil(clk_mgr_base->clks.dramclk_khz));
 
-		if (clk_mgr_base->clks.fclk_p_state_change_support &&
-				(update_uclk || !clk_mgr_base->clks.fclk_prev_p_state_change_support)) {
-
+		if (clk_mgr_base->ctx->dce_version != DCN_VERSION_3_21 && clk_mgr_base->clks.fclk_p_state_change_support && update_fclk) {
 			/* Handle the code for sending a message to PMFW that FCLK P-state change is supported */
 			dcn32_smu_send_fclk_pstate_message(clk_mgr, FCLK_PSTATE_SUPPORTED);
 		}

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_clk_mgr_smu_msg.h

@@ -33,7 +33,6 @@
 #define FCLK_PSTATE_SUPPORTED          0x01
 
 /* TODO Remove this MSG ID define after it becomes available in dalsmc */
-#define DALSMC_MSG_SetFclkSwitchAllow	0x11
 #define DALSMC_MSG_SetCabForUclkPstate	0x12
 #define DALSMC_Result_OK				0x1