drm/amd/display: Fork thread to offload work of hpd_rx_irq

From Wayne Lin
e980e1d978e0eb4c0399cff37f175779237db53b in linux 5.15.y/5.15.58
8e794421bc981586d0af4e959ec76d668c793a55 in mainline linux

4 files changed, 219 insertions, 48 deletions

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index c3bbeb5a9e6..b905e164b25 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1238,6 +1238,83 @@ static void vblank_control_worker(struct work_struct *work)
 }
 
 #endif
+
+static void dm_handle_hpd_rx_offload_work(struct work_struct *work)
+{
+	struct hpd_rx_irq_offload_work *offload_work;
+	struct amdgpu_dm_connector *aconnector;
+	struct dc_link *dc_link;
+	struct amdgpu_device *adev;
+	enum dc_connection_type new_connection_type = dc_connection_none;
+	unsigned long flags;
+
+	offload_work = container_of(work, struct hpd_rx_irq_offload_work, work);
+	aconnector = offload_work->offload_wq->aconnector;
+
+	if (!aconnector) {
+		DRM_ERROR("Can't retrieve aconnector in hpd_rx_irq_offload_work");
+		goto skip;
+	}
+
+	adev = drm_to_adev(aconnector->base.dev);
+	dc_link = aconnector->dc_link;
+
+	mutex_lock(&aconnector->hpd_lock);
+	if (!dc_link_detect_sink(dc_link, &new_connection_type))
+		DRM_ERROR("KMS: Failed to detect connector\n");
+	mutex_unlock(&aconnector->hpd_lock);
+
+	if (new_connection_type == dc_connection_none)
+		goto skip;
+
+	if (amdgpu_in_reset(adev))
+		goto skip;
+
+	mutex_lock(&adev->dm.dc_lock);
+	if (offload_work->data.bytes.device_service_irq.bits.AUTOMATED_TEST)
+		dc_link_dp_handle_automated_test(dc_link);
+	else if ((dc_link->connector_signal != SIGNAL_TYPE_EDP) &&
+			hpd_rx_irq_check_link_loss_status(dc_link, &offload_work->data) &&
+			dc_link_dp_allow_hpd_rx_irq(dc_link)) {
+		dc_link_dp_handle_link_loss(dc_link);
+		spin_lock_irqsave(&offload_work->offload_wq->offload_lock, flags);
+		offload_work->offload_wq->is_handling_link_loss = false;
+		spin_unlock_irqrestore(&offload_work->offload_wq->offload_lock, flags);
+	}
+	mutex_unlock(&adev->dm.dc_lock);
+
+skip:
+	kfree(offload_work);
+
+}
+
+static struct hpd_rx_irq_offload_work_queue *hpd_rx_irq_create_workqueue(struct dc *dc)
+{
+	int max_caps = dc->caps.max_links;
+	int i = 0;
+	struct hpd_rx_irq_offload_work_queue *hpd_rx_offload_wq = NULL;
+
+	hpd_rx_offload_wq = kcalloc(max_caps, sizeof(*hpd_rx_offload_wq), GFP_KERNEL);
+
+	if (!hpd_rx_offload_wq)
+		return NULL;
+
+
+	for (i = 0; i < max_caps; i++) {
+		hpd_rx_offload_wq[i].wq =
+				    create_singlethread_workqueue("amdgpu_dm_hpd_rx_offload_wq");
+
+		if (hpd_rx_offload_wq[i].wq == NULL) {
+			DRM_ERROR("create amdgpu_dm_hpd_rx_offload_wq fail!");
+			return NULL;
+		}
+
+		mtx_init(&hpd_rx_offload_wq[i].offload_lock, IPL_TTY);
+	}
+
+	return hpd_rx_offload_wq;
+}
+
 static int amdgpu_dm_init(struct amdgpu_device *adev)
 {
 	struct dc_init_data init_data;
@@ -1364,6 +1441,12 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 
 	dc_hardware_init(adev->dm.dc);
 
+	adev->dm.hpd_rx_offload_wq = hpd_rx_irq_create_workqueue(adev->dm.dc);
+	if (!adev->dm.hpd_rx_offload_wq) {
+		DRM_ERROR("amdgpu: failed to create hpd rx offload workqueue.\n");
+		goto error;
+	}
+
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 	if ((adev->flags & AMD_IS_APU) && (adev->asic_type >= CHIP_CARRIZO)) {
 		struct dc_phy_addr_space_config pa_config;
@@ -1543,6 +1626,18 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev)
 		adev->dm.freesync_module = NULL;
 	}
 
+	if (adev->dm.hpd_rx_offload_wq) {
+		for (i = 0; i < adev->dm.dc->caps.max_links; i++) {
+			if (adev->dm.hpd_rx_offload_wq[i].wq) {
+				destroy_workqueue(adev->dm.hpd_rx_offload_wq[i].wq);
+				adev->dm.hpd_rx_offload_wq[i].wq = NULL;
+			}
+		}
+
+		kfree(adev->dm.hpd_rx_offload_wq);
+		adev->dm.hpd_rx_offload_wq = NULL;
+	}
+
 	mutex_destroy(&adev->dm.audio_lock);
 	mutex_destroy(&adev->dm.dc_lock);
 
@@ -2162,6 +2257,16 @@ context_alloc_fail:
 	return res;
 }
 
+static void hpd_rx_irq_work_suspend(struct amdgpu_display_manager *dm)
+{
+	int i;
+
+	if (dm->hpd_rx_offload_wq) {
+		for (i = 0; i < dm->dc->caps.max_links; i++)
+			flush_workqueue(dm->hpd_rx_offload_wq[i].wq);
+	}
+}
+
 static int dm_suspend(void *handle)
 {
 	struct amdgpu_device *adev = handle;
@@ -2183,6 +2288,8 @@ static int dm_suspend(void *handle)
 
 		amdgpu_dm_irq_suspend(adev);
 
+		hpd_rx_irq_work_suspend(dm);
+
 		return ret;
 	}
 
@@ -2193,6 +2300,8 @@ static int dm_suspend(void *handle)
 
 	amdgpu_dm_irq_suspend(adev);
 
+	hpd_rx_irq_work_suspend(dm);
+
 	dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D3);
 
 	return 0;
@@ -2871,8 +2980,7 @@ static void handle_hpd_irq(void *param)
 
 }
 
-
-static void dm_handle_hpd_rx_irq(struct amdgpu_dm_connector *aconnector)
+static void dm_handle_mst_sideband_msg(struct amdgpu_dm_connector *aconnector)
 {
 	uint8_t esi[DP_PSR_ERROR_STATUS - DP_SINK_COUNT_ESI] = { 0 };
 	uint8_t dret;
@@ -2950,6 +3058,25 @@ static void dm_handle_hpd_rx_irq(struct amdgpu_dm_connector *aconnector)
 		DRM_DEBUG_DRIVER("Loop exceeded max iterations\n");
 }
 
+static void schedule_hpd_rx_offload_work(struct hpd_rx_irq_offload_work_queue *offload_wq,
+							union hpd_irq_data hpd_irq_data)
+{
+	struct hpd_rx_irq_offload_work *offload_work =
+				kzalloc(sizeof(*offload_work), GFP_KERNEL);
+
+	if (!offload_work) {
+		DRM_ERROR("Failed to allocate hpd_rx_irq_offload_work.\n");
+		return;
+	}
+
+	INIT_WORK(&offload_work->work, dm_handle_hpd_rx_offload_work);
+	offload_work->data = hpd_irq_data;
+	offload_work->offload_wq = offload_wq;
+
+	queue_work(offload_wq->wq, &offload_work->work);
+	DRM_DEBUG_KMS("queue work to handle hpd_rx offload work");
+}
+
 static void handle_hpd_rx_irq(void *param)
 {
 	struct amdgpu_dm_connector *aconnector = (struct amdgpu_dm_connector *)param;
@@ -2961,14 +3088,16 @@ static void handle_hpd_rx_irq(void *param)
 	enum dc_connection_type new_connection_type = dc_connection_none;
 	struct amdgpu_device *adev = drm_to_adev(dev);
 	union hpd_irq_data hpd_irq_data;
-	bool lock_flag = 0;
+	bool link_loss = false;
+	bool has_left_work = false;
+	int idx = aconnector->base.index;
+	struct hpd_rx_irq_offload_work_queue *offload_wq = &adev->dm.hpd_rx_offload_wq[idx];
 
 	memset(&hpd_irq_data, 0, sizeof(hpd_irq_data));
 
 	if (adev->dm.disable_hpd_irq)
 		return;
 
-
 	/*
 	 * TODO:Temporary add mutex to protect hpd interrupt not have a gpio
 	 * conflict, after implement i2c helper, this mutex should be
@@ -2976,43 +3105,41 @@ static void handle_hpd_rx_irq(void *param)
 	 */
 	mutex_lock(&aconnector->hpd_lock);
 
-	read_hpd_rx_irq_data(dc_link, &hpd_irq_data);
+	result = dc_link_handle_hpd_rx_irq(dc_link, &hpd_irq_data,
+						&link_loss, true, &has_left_work);
 
-	if ((dc_link->cur_link_settings.lane_count != LANE_COUNT_UNKNOWN) ||
-		(dc_link->type == dc_connection_mst_branch)) {
-		if (hpd_irq_data.bytes.device_service_irq.bits.UP_REQ_MSG_RDY) {
-			result = true;
-			dm_handle_hpd_rx_irq(aconnector);
-			goto out;
-		} else if (hpd_irq_data.bytes.device_service_irq.bits.DOWN_REP_MSG_RDY) {
-			result = false;
-			dm_handle_hpd_rx_irq(aconnector);
+	if (!has_left_work)
+		goto out;
+
+	if (hpd_irq_data.bytes.device_service_irq.bits.AUTOMATED_TEST) {
+		schedule_hpd_rx_offload_work(offload_wq, hpd_irq_data);
+		goto out;
+	}
+
+	if (dc_link_dp_allow_hpd_rx_irq(dc_link)) {
+		if (hpd_irq_data.bytes.device_service_irq.bits.UP_REQ_MSG_RDY ||
+			hpd_irq_data.bytes.device_service_irq.bits.DOWN_REP_MSG_RDY) {
+			dm_handle_mst_sideband_msg(aconnector);
 			goto out;
 		}
-	}
 
-	/*
-	 * TODO: We need the lock to avoid touching DC state while it's being
-	 * modified during automated compliance testing, or when link loss
-	 * happens. While this should be split into subhandlers and proper
-	 * interfaces to avoid having to conditionally lock like this in the
-	 * outer layer, we need this workaround temporarily to allow MST
-	 * lightup in some scenarios to avoid timeout.
-	 */
-	if (!amdgpu_in_reset(adev) &&
-	    (hpd_rx_irq_check_link_loss_status(dc_link, &hpd_irq_data) ||
-	     hpd_irq_data.bytes.device_service_irq.bits.AUTOMATED_TEST)) {
-		mutex_lock(&adev->dm.dc_lock);
-		lock_flag = 1;
-	}
+		if (link_loss) {
+			bool skip = false;
 
-#ifdef CONFIG_DRM_AMD_DC_HDCP
-	result = dc_link_handle_hpd_rx_irq(dc_link, &hpd_irq_data, NULL);
-#else
-	result = dc_link_handle_hpd_rx_irq(dc_link, NULL, NULL);
-#endif
-	if (!amdgpu_in_reset(adev) && lock_flag)
-		mutex_unlock(&adev->dm.dc_lock);
+			spin_lock(&offload_wq->offload_lock);
+			skip = offload_wq->is_handling_link_loss;
+
+			if (!skip)
+				offload_wq->is_handling_link_loss = true;
+
+			spin_unlock(&offload_wq->offload_lock);
+
+			if (!skip)
+				schedule_hpd_rx_offload_work(offload_wq, hpd_irq_data);
+
+			goto out;
+		}
+	}
 
 out:
 	if (result && !is_mst_root_connector) {
@@ -3097,6 +3224,10 @@ static void register_hpd_handlers(struct amdgpu_device *adev)
 			amdgpu_dm_irq_register_interrupt(adev, &int_params,
 					handle_hpd_rx_irq,
 					(void *) aconnector);
+
+			if (adev->dm.hpd_rx_offload_wq)
+				adev->dm.hpd_rx_offload_wq[connector->index].aconnector =
+					aconnector;
 		}
 	}
 }
diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 54d7e8482ff..24231c9d9b1 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -172,6 +172,48 @@ struct dal_allocation {
 };
 
 /**
+ * struct hpd_rx_irq_offload_work_queue - Work queue to handle hpd_rx_irq
+ * offload work
+ */
+struct hpd_rx_irq_offload_work_queue {
+	/**
+	 * @wq: workqueue structure to queue offload work.
+	 */
+	struct workqueue_struct *wq;
+	/**
+	 * @offload_lock: To protect fields of offload work queue.
+	 */
+	spinlock_t offload_lock;
+	/**
+	 * @is_handling_link_loss: Used to prevent inserting link loss event when
+	 * we're handling link loss
+	 */
+	bool is_handling_link_loss;
+	/**
+	 * @aconnector: The aconnector that this work queue is attached to
+	 */
+	struct amdgpu_dm_connector *aconnector;
+};
+
+/**
+ * struct hpd_rx_irq_offload_work - hpd_rx_irq offload work structure
+ */
+struct hpd_rx_irq_offload_work {
+	/**
+	 * @work: offload work
+	 */
+	struct work_struct work;
+	/**
+	 * @data: reference irq data which is used while handling offload work
+	 */
+	union hpd_irq_data data;
+	/**
+	 * @offload_wq: offload work queue that this work is queued to
+	 */
+	struct hpd_rx_irq_offload_work_queue *offload_wq;
+};
+
+/**
  * struct amdgpu_display_manager - Central amdgpu display manager device
  *
  * @dc: Display Core control structure
@@ -461,7 +503,12 @@ struct amdgpu_display_manager {
 	 */
 	struct crc_rd_work *crc_rd_wrk;
 #endif
-
+	/**
+	 * @hpd_rx_offload_wq:
+	 *
+	 * Work queue to offload works of hpd_rx_irq
+	 */
+	struct hpd_rx_irq_offload_work_queue *hpd_rx_offload_wq;
 	/**
 	 * @mst_encoders:
 	 *
diff --git a/sys/dev/pci/drm/amd/display/dc/core/dc_link_dp.c b/sys/dev/pci/drm/amd/display/dc/core/dc_link_dp.c
index e6dec86d212..2b34b94ce37 100644
--- a/sys/dev/pci/drm/amd/display/dc/core/dc_link_dp.c
+++ b/sys/dev/pci/drm/amd/display/dc/core/dc_link_dp.c
@@ -2075,7 +2075,7 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link)
 	return max_link_cap;
 }
 
-enum dc_status read_hpd_rx_irq_data(
+static enum dc_status read_hpd_rx_irq_data(
 	struct dc_link *link,
 	union hpd_irq_data *irq_data)
 {
@@ -3257,7 +3257,7 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 	}
 }
 
-static bool handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_irq_dpcd_data, bool *out_link_loss,
+bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_irq_dpcd_data, bool *out_link_loss,
 							bool defer_handling, bool *has_left_work)
 {
 	union hpd_irq_data hpd_irq_dpcd_data = { { { {0} } } };
@@ -3379,11 +3379,6 @@ static bool handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_
 	return status;
 }
 
-bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_irq_dpcd_data, bool *out_link_loss)
-{
-	return handle_hpd_rx_irq(link, out_hpd_irq_dpcd_data, out_link_loss, false, NULL);
-}
-
 /*query dpcd for version and mst cap addresses*/
 bool is_mst_supported(struct dc_link *link)
 {
diff --git a/sys/dev/pci/drm/amd/display/dc/dc_link.h b/sys/dev/pci/drm/amd/display/dc/dc_link.h
index bde6bcb9b5f..8ad431f698e 100644
--- a/sys/dev/pci/drm/amd/display/dc/dc_link.h
+++ b/sys/dev/pci/drm/amd/display/dc/dc_link.h
@@ -296,7 +296,8 @@ enum dc_status dc_link_allocate_mst_payload(struct pipe_ctx *pipe_ctx);
  * false - no change in Downstream port status. No further action required
  * from DM. */
 bool dc_link_handle_hpd_rx_irq(struct dc_link *dc_link,
-		union hpd_irq_data *hpd_irq_dpcd_data, bool *out_link_loss);
+		union hpd_irq_data *hpd_irq_dpcd_data, bool *out_link_loss,
+		bool defer_handling, bool *has_left_work);
 
 /*
  * On eDP links this function call will stall until T12 has elapsed.
@@ -305,9 +306,6 @@ bool dc_link_handle_hpd_rx_irq(struct dc_link *dc_link,
  */
 bool dc_link_wait_for_t12(struct dc_link *link);
 
-enum dc_status read_hpd_rx_irq_data(
-	struct dc_link *link,
-	union hpd_irq_data *irq_data);
 void dc_link_dp_handle_automated_test(struct dc_link *link);
 void dc_link_dp_handle_link_loss(struct dc_link *link);
 bool dc_link_dp_allow_hpd_rx_irq(const struct dc_link *link);