drm/amd/display: Reduce CPU busy-waiting for long delays

[WHY]
udelay should not be used for long waits since it keeps CPU active,
wasting power.

[HOW]
Use fsleep where acceptable to allow CPU cores to be parked by the scheduler.
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_aux.c

@@ -832,13 +832,8 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 									LOG_FLAG_I2cAux_DceAux,
 									"dce_aux_transfer_with_retries: payload->defer_delay=%u",
 									payload->defer_delay);
-						if (payload->defer_delay > 1) {
-							msleep(payload->defer_delay);
-							defer_time_in_ms += payload->defer_delay;
-						} else if (payload->defer_delay <= 1) {
-							udelay(payload->defer_delay * 1000);
-							defer_time_in_ms += payload->defer_delay;
-						}
+						fsleep(payload->defer_delay * 1000);
+						defer_time_in_ms += payload->defer_delay;
 					}
 				}
 				break;

drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c

@@ -586,7 +586,7 @@ static void dcn10_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 				if (state == PSR_STATE0)
 					break;
 			}
-			udelay(500);
+			fsleep(500);
 		}
 
 		/* assert if max retry hit */

drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c

@@ -215,7 +215,7 @@ static void dmub_psr_enable(struct dmub_psr *dmub, bool enable, bool wait, uint8
 					break;
 			}
 
-			udelay(500);
+			fsleep(500);
 		}
 
 		/* assert if max retry hit */

drivers/gpu/drm/amd/display/dc/link/link_dpms.c

@@ -1153,7 +1153,7 @@ static bool poll_for_allocation_change_trigger(struct dc_link *link)
 			break;
 		}
 
-		msleep(5);
+		fsleep(5000);
 	}
 
 	if (result == ACT_FAILED) {
@@ -1640,7 +1640,7 @@ static bool write_128b_132b_sst_payload_allocation_table(
 			}
 		}
 		retries++;
-		msleep(5);
+		fsleep(5000);
 	}
 
 	if (!result && retries == max_retries) {

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c

@@ -1005,7 +1005,7 @@ static enum dc_status wake_up_aux_channel(struct dc_link *link)
 		 * signal and may need up to 1 ms before being able to reply.
 		 */
 		if (status != DC_OK || dpcd_power_state == DP_SET_POWER_D3) {
-			udelay(1000);
+			fsleep(1000);
 			aux_channel_retry_cnt++;
 		}
 	}
@@ -2121,7 +2121,7 @@ static bool dp_verify_link_cap(
 
 		if (status == LINK_TRAINING_SUCCESS) {
 			success = true;
-			udelay(1000);
+			fsleep(1000);
 			if (dc_link_dp_read_hpd_rx_irq_data(link, &irq_data) == DC_OK &&
 					dc_link_check_link_loss_status(
 							link,
@@ -2171,7 +2171,7 @@ bool dp_verify_link_cap_with_retries(
 			success = true;
 			break;
 		}
-		msleep(10);
+		fsleep(10 * 1000);
 	}
 
 	dp_trace_lt_fail_count_update(link, fail_count, true);
@@ -2231,7 +2231,7 @@ bool dc_link_is_dp_sink_present(struct dc_link *link)
 		gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin);
 		ASSERT(gpio_result == GPIO_RESULT_OK);
 		if (clock_pin)
-			udelay(1000);
+			fsleep(1000);
 		else
 			break;
 	} while (retry++ < 3);

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c

@@ -424,7 +424,7 @@ int dc_link_dp_dpia_handle_usb4_bandwidth_allocation_for_link(struct dc_link *li
 				timeout--;
 			else
 				break;
-			udelay(10 * 1000);
+			fsleep(10 * 1000);
 		} while (!get_cm_response_ready_flag(link));
 
 		if (!timeout)

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c

@@ -258,10 +258,7 @@ void dp_wait_for_training_aux_rd_interval(
 	struct dc_link *link,
 	uint32_t wait_in_micro_secs)
 {
-	if (wait_in_micro_secs > 1000)
-		msleep(wait_in_micro_secs/1000);
-	else
-		udelay(wait_in_micro_secs);
+	fsleep(wait_in_micro_secs);
 
 	DC_LOG_HW_LINK_TRAINING("%s:\n wait = %d\n",
 		__func__,
@@ -970,7 +967,7 @@ static void dpcd_exit_training_mode(struct dc_link *link, enum dp_link_encoding
 			if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) &&
 					(sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0)
 				break;
-			udelay(1000);
+			fsleep(1000);
 		}
 	}
 }

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_dpia.c

@@ -1035,7 +1035,7 @@ enum link_training_result dc_link_dpia_perform_link_training(
 	 * falling back to lower bandwidth settings possible.
 	 */
 	if (result == LINK_TRAINING_SUCCESS) {
-		msleep(5);
+		fsleep(5000);
 		if (!link->is_automated)
 			result = dp_check_link_loss_status(link, &lt_settings);
 	} else if (result == LINK_TRAINING_ABORT)

drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c

@@ -325,7 +325,7 @@ bool dc_link_wait_for_t12(struct dc_link *link)
 void link_edp_add_delay_for_T9(struct dc_link *link)
 {
 	if (link && link->panel_config.pps.extra_delay_backlight_off > 0)
-		udelay(link->panel_config.pps.extra_delay_backlight_off * 1000);
+		fsleep(link->panel_config.pps.extra_delay_backlight_off * 1000);
 }
 
 bool link_edp_receiver_ready_T9(struct dc_link *link)
@@ -383,7 +383,7 @@ bool link_edp_receiver_ready_T7(struct dc_link *link)
 	}
 
 	if (link && link->panel_config.pps.extra_t7_ms > 0)
-		udelay(link->panel_config.pps.extra_t7_ms * 1000);
+		fsleep(link->panel_config.pps.extra_t7_ms * 1000);
 
 	return result;
 }