drm/amd/display: make underflow status clear explicit

[why]
HUBP underflow is never cleared, which causes underflow in one
test to fail another test, violating the independence requirements

[how]
Rather than make clearing implicit, we explicitly clear underflow
status in DTN.
Signed-off-by: Jun Lei <Jun.Lei@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/dcn10/dcn10_hubp.c

@@ -99,6 +99,14 @@ static unsigned int hubp1_get_underflow_status(struct hubp *hubp)
 	return hubp_underflow;
 }
 
+
+void hubp1_clear_underflow(struct hubp *hubp)
+{
+	struct dcn10_hubp *hubp1 = TO_DCN10_HUBP(hubp);
+
+	REG_UPDATE(DCHUBP_CNTL, HUBP_UNDERFLOW_CLEAR, 1);
+}
+
 static void hubp1_set_hubp_blank_en(struct hubp *hubp, bool blank)
 {
 	struct dcn10_hubp *hubp1 = TO_DCN10_HUBP(hubp);
@@ -1190,6 +1198,7 @@ static const struct hubp_funcs dcn10_hubp_funcs = {
 	.hubp_clk_cntl = hubp1_clk_cntl,
 	.hubp_vtg_sel = hubp1_vtg_sel,
 	.hubp_read_state = hubp1_read_state,
+	.hubp_clear_underflow = hubp1_clear_underflow,
 	.hubp_disable_control =  hubp1_disable_control,
 	.hubp_get_underflow_status = hubp1_get_underflow_status,
 

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubp.h

@@ -251,6 +251,7 @@
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_BLANK_EN, mask_sh),\
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_TTU_DISABLE, mask_sh),\
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_UNDERFLOW_STATUS, mask_sh),\
+	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_UNDERFLOW_CLEAR, mask_sh),\
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_NO_OUTSTANDING_REQ, mask_sh),\
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_VTG_SEL, mask_sh),\
 	HUBP_SF(HUBP0_DCHUBP_CNTL, HUBP_DISABLE, mask_sh),\
@@ -435,6 +436,7 @@
 	type HUBP_NO_OUTSTANDING_REQ;\
 	type HUBP_VTG_SEL;\
 	type HUBP_UNDERFLOW_STATUS;\
+	type HUBP_UNDERFLOW_CLEAR;\
 	type NUM_PIPES;\
 	type NUM_BANKS;\
 	type PIPE_INTERLEAVE;\
@@ -739,6 +741,7 @@ void dcn10_hubp_construct(
 	const struct dcn_mi_mask *hubp_mask);
 
 void hubp1_read_state(struct hubp *hubp);
+void hubp1_clear_underflow(struct hubp *hubp);
 
 enum cursor_pitch hubp1_get_cursor_pitch(unsigned int pitch);
 

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -2710,6 +2710,7 @@ static const struct hw_sequencer_funcs dcn10_funcs = {
 	.set_avmute = dce110_set_avmute,
 	.log_hw_state = dcn10_log_hw_state,
 	.get_hw_state = dcn10_get_hw_state,
+	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
 	.edp_backlight_control = hwss_edp_backlight_control,
 	.edp_power_control = hwss_edp_power_control,

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.h

@@ -51,6 +51,8 @@ void dcn10_get_hw_state(
 		char *pBuf, unsigned int bufSize,
 		unsigned int mask);
 
+void dcn10_clear_status_bits(struct dc *dc, unsigned int mask);
+
 bool is_lower_pipe_tree_visible(struct pipe_ctx *pipe_ctx);
 
 bool is_upper_pipe_tree_visible(struct pipe_ctx *pipe_ctx);

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer_debug.c

@@ -454,12 +454,6 @@ static unsigned int dcn10_get_otg_states(struct dc *dc, char *pBuf, unsigned int
 
 			remaining_buffer -= chars_printed;
 			pBuf += chars_printed;
-
-			// Clear underflow for debug purposes
-			// We want to keep underflow sticky bit on for the longevity tests outside of test environment.
-			// This function is called only from Windows or Diags test environment, hence it's safe to clear
-			// it from here without affecting the original intent.
-			tg->funcs->clear_optc_underflow(tg);
 		}
 	}
 
@@ -484,6 +478,59 @@ static unsigned int dcn10_get_clock_states(struct dc *dc, char *pBuf, unsigned i
 	return chars_printed;
 }
 
+static void dcn10_clear_otpc_underflow(struct dc *dc)
+{
+	struct resource_pool *pool = dc->res_pool;
+	int i;
+
+	for (i = 0; i < pool->timing_generator_count; i++) {
+		struct timing_generator *tg = pool->timing_generators[i];
+		struct dcn_otg_state s = {0};
+
+		optc1_read_otg_state(DCN10TG_FROM_TG(tg), &s);
+
+		if (s.otg_enabled & 1)
+			tg->funcs->clear_optc_underflow(tg);
+	}
+}
+
+static void dcn10_clear_hubp_underflow(struct dc *dc)
+{
+	struct resource_pool *pool = dc->res_pool;
+	int i;
+
+	for (i = 0; i < pool->pipe_count; i++) {
+		struct hubp *hubp = pool->hubps[i];
+		struct dcn_hubp_state *s = &(TO_DCN10_HUBP(hubp)->state);
+
+		hubp->funcs->hubp_read_state(hubp);
+
+		if (!s->blank_en)
+			hubp->funcs->hubp_clear_underflow(hubp);
+	}
+}
+
+void dcn10_clear_status_bits(struct dc *dc, unsigned int mask)
+{
+	/*
+	 *  Mask Format
+	 *  Bit 0 - 31: Status bit to clear
+	 *
+	 *  Mask = 0x0 means clear all status bits
+	 */
+	const unsigned int DC_HW_STATE_MASK_HUBP_UNDERFLOW	= 0x1;
+	const unsigned int DC_HW_STATE_MASK_OTPC_UNDERFLOW	= 0x2;
+
+	if (mask == 0x0)
+		mask = 0xFFFFFFFF;
+
+	if (mask & DC_HW_STATE_MASK_HUBP_UNDERFLOW)
+		dcn10_clear_hubp_underflow(dc);
+
+	if (mask & DC_HW_STATE_MASK_OTPC_UNDERFLOW)
+		dcn10_clear_otpc_underflow(dc);
+}
+
 void dcn10_get_hw_state(struct dc *dc, char *pBuf, unsigned int bufSize, unsigned int mask)
 {
 	/*

drivers/gpu/drm/amd/display/dc/inc/hw/hubp.h

@@ -121,6 +121,7 @@ struct hubp_funcs {
 	void (*hubp_clk_cntl)(struct hubp *hubp, bool enable);
 	void (*hubp_vtg_sel)(struct hubp *hubp, uint32_t otg_inst);
 	void (*hubp_read_state)(struct hubp *hubp);
+	void (*hubp_clear_underflow)(struct hubp *hubp);
 	void (*hubp_disable_control)(struct hubp *hubp, bool disable_hubp);
 	unsigned int (*hubp_get_underflow_status)(struct hubp *hubp);
 

drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h

@@ -200,6 +200,7 @@ struct hw_sequencer_funcs {
 	void (*log_hw_state)(struct dc *dc,
 		struct dc_log_buffer_ctx *log_ctx);
 	void (*get_hw_state)(struct dc *dc, char *pBuf, unsigned int bufSize, unsigned int mask);
+	void (*clear_status_bits)(struct dc *dc, unsigned int mask);
 
 	void (*wait_for_mpcc_disconnect)(struct dc *dc,
 			struct resource_pool *res_pool,