drm: apple: Extract modeset crtc's atomic_flush()

Triggering modesets from drm_connector_helper_funcs.atomic_check is more
in line with DRM/KMS' design and allows returning errors from failed
modesets.
Ignore hotplug callbacks from DCP during modeset. DCP always does
disconnected -> connected on (at least the initial) modeset. Shield drm
helpers from this.
This improves reliability with externel (dptx based) displays.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/apple_drv.c

@@ -300,6 +300,8 @@ static const struct drm_connector_funcs apple_connector_funcs = {
 static const struct drm_connector_helper_funcs apple_connector_helper_funcs = {
 	.get_modes		= dcp_get_modes,
 	.mode_valid		= dcp_mode_valid,
+	.atomic_check		= dcp_connector_atomic_check,
+
 };
 
 static const struct drm_crtc_helper_funcs apple_crtc_helper_funcs = {

drivers/gpu/drm/apple/dcp-internal.h

@@ -172,6 +172,7 @@ struct apple_dcp {
 	u32 last_swap_id;
 
 	/* Current display mode */
+	bool during_modeset;
 	bool valid_mode;
 	struct dcp_set_digital_out_mode_req mode;
 

drivers/gpu/drm/apple/dcp.h

@@ -57,6 +57,8 @@ void dcp_drm_crtc_vblank(struct apple_crtc *crtc);
 int dcp_get_modes(struct drm_connector *connector);
 int dcp_mode_valid(struct drm_connector *connector,
 		   struct drm_display_mode *mode);
+int dcp_connector_atomic_check(struct drm_connector *connector,
+			       struct drm_atomic_state *state);
 bool dcp_crtc_mode_fixup(struct drm_crtc *crtc,
 			 const struct drm_display_mode *mode,
 			 struct drm_display_mode *adjusted_mode);

drivers/gpu/drm/apple/iomfb.c

@@ -422,6 +422,47 @@ int dcp_mode_valid(struct drm_connector *connector,
 }
 EXPORT_SYMBOL_GPL(dcp_mode_valid);
 
+int dcp_connector_atomic_check(struct drm_connector *connector,
+			       struct drm_atomic_state *state)
+{
+	struct apple_connector *apple_connector = to_apple_connector(connector);
+	struct platform_device *pdev = apple_connector->dcp;
+	struct apple_dcp *dcp = platform_get_drvdata(pdev);
+	struct drm_crtc *crtc = &dcp->crtc->base;
+	struct drm_crtc_state *crtc_state;
+	int ret = -EIO;
+	bool modeset;
+
+	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+	if (!crtc_state)
+		return 0;
+
+	modeset = drm_atomic_crtc_needs_modeset(crtc_state) || !dcp->valid_mode;
+
+	if (!modeset)
+		return 0;
+
+	/* ignore no mode, poweroff is handled elsewhere */
+	if (crtc_state->mode.hdisplay == 0 && crtc_state->mode.vdisplay == 0)
+		return 0;
+
+	switch (dcp->fw_compat) {
+	case DCP_FIRMWARE_V_12_3:
+		ret = iomfb_modeset_v12_3(dcp, crtc_state);
+		break;
+	case DCP_FIRMWARE_V_13_5:
+		ret = iomfb_modeset_v13_3(dcp, crtc_state);
+		break;
+	default:
+		WARN_ONCE(true, "Unexpected firmware version: %u\n",
+			  dcp->fw_compat);
+		break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dcp_connector_atomic_check);
+
 bool dcp_crtc_mode_fixup(struct drm_crtc *crtc,
 			 const struct drm_display_mode *mode,
 			 struct drm_display_mode *adjusted_mode)

drivers/gpu/drm/apple/iomfb_template.c

@@ -1014,6 +1014,13 @@ static void dcpep_cb_hotplug(struct apple_dcp *dcp, u64 *connected)
 	if (dcp->main_display)
 		return;
 
+	if (dcp->during_modeset) {
+		dev_info(dcp->dev,
+			 "cb_hotplug() ignored during modeset connected:%llu\n",
+			 *connected);
+		return;
+	}
+
 	dev_info(dcp->dev, "cb_hotplug() connected:%llu, valid_mode:%d\n",
 		 *connected, dcp->valid_mode);
 
@@ -1178,6 +1185,75 @@ static void complete_set_digital_out_mode(struct apple_dcp *dcp, void *data,
 	}
 }
 
+int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
+			       struct drm_crtc_state *crtc_state)
+{
+	struct dcp_display_mode *mode;
+	struct dcp_wait_cookie *cookie;
+	int ret;
+
+	mode = lookup_mode(dcp, &crtc_state->mode);
+	if (!mode) {
+		dev_err(dcp->dev, "no match for " DRM_MODE_FMT "\n",
+			DRM_MODE_ARG(&crtc_state->mode));
+		return -EIO;
+	}
+
+	dev_info(dcp->dev,
+		 "set_digital_out_mode(color:%d timing:%d) " DRM_MODE_FMT "\n",
+		 mode->color_mode_id, mode->timing_mode_id,
+		 DRM_MODE_ARG(&crtc_state->mode));
+	dcp->mode = (struct dcp_set_digital_out_mode_req){
+		.color_mode_id = mode->color_mode_id,
+		.timing_mode_id = mode->timing_mode_id
+	};
+
+	cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
+	if (!cookie) {
+		return -ENOMEM;
+	}
+
+	init_completion(&cookie->done);
+	kref_init(&cookie->refcount);
+	/* increase refcount to ensure the receiver has a reference */
+	kref_get(&cookie->refcount);
+
+	dcp->during_modeset = true;
+
+	dcp_set_digital_out_mode(dcp, false, &dcp->mode,
+				 complete_set_digital_out_mode, cookie);
+
+	/*
+	 * The DCP firmware has an internal timeout of ~8 seconds for
+	 * modesets. Add an extra 500ms to safe side that the modeset
+	 * call has returned.
+	 */
+	dev_dbg(dcp->dev, "%s - wait for modeset", __func__);
+	ret = wait_for_completion_timeout(&cookie->done,
+					  msecs_to_jiffies(8500));
+
+	kref_put(&cookie->refcount, release_wait_cookie);
+	dcp->during_modeset = false;
+	dev_info(dcp->dev, "set_digital_out_mode finished:%d\n", ret);
+
+	if (ret == 0) {
+		dev_info(dcp->dev, "set_digital_out_mode timed out\n");
+		return -EIO;
+	} else if (ret < 0) {
+		dev_info(dcp->dev,
+			 "waiting on set_digital_out_mode failed:%d\n", ret);
+		return -EIO;
+
+	} else if (ret > 0) {
+		dev_dbg(dcp->dev,
+			"set_digital_out_mode finished with %d to spare\n",
+			jiffies_to_msecs(ret));
+	}
+	dcp->valid_mode = true;
+
+	return 0;
+}
+
 void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, struct drm_atomic_state *state)
 {
 	struct drm_plane *plane;
@@ -1186,13 +1262,10 @@ void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, stru
 	struct DCP_FW_NAME(dcp_swap_submit_req) *req = &DCP_FW_UNION(dcp->swap);
 	int plane_idx, l;
 	int has_surface = 0;
-	bool modeset;
 	dev_dbg(dcp->dev, "%s", __func__);
 
 	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
-	modeset = drm_atomic_crtc_needs_modeset(crtc_state) || !dcp->valid_mode;
-
 	/* Reset to defaults */
 	memset(req, 0, sizeof(*req));
 	for (l = 0; l < SWAP_SURFACES; l++)
@@ -1305,64 +1378,6 @@ void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, stru
 		l += 1;
 	}
 
-	if (modeset) {
-		struct dcp_display_mode *mode;
-		struct dcp_wait_cookie *cookie;
-		int ret;
-
-		mode = lookup_mode(dcp, &crtc_state->mode);
-		if (!mode) {
-			dev_warn(dcp->dev, "no match for " DRM_MODE_FMT,
-				 DRM_MODE_ARG(&crtc_state->mode));
-			schedule_work(&dcp->vblank_wq);
-			return;
-		}
-
-		dev_info(dcp->dev, "set_digital_out_mode(color:%d timing:%d)",
-			 mode->color_mode_id, mode->timing_mode_id);
-		dcp->mode = (struct dcp_set_digital_out_mode_req){
-			.color_mode_id = mode->color_mode_id,
-			.timing_mode_id = mode->timing_mode_id
-		};
-
-		cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
-		if (!cookie) {
-			schedule_work(&dcp->vblank_wq);
-			return;
-		}
-
-		init_completion(&cookie->done);
-		kref_init(&cookie->refcount);
-		/* increase refcount to ensure the receiver has a reference */
-		kref_get(&cookie->refcount);
-
-		dcp_set_digital_out_mode(dcp, false, &dcp->mode,
-					 complete_set_digital_out_mode, cookie);
-
-		/*
-		 * The DCP firmware has an internal timeout of ~8 seconds for
-		 * modesets. Add an extra 500ms to safe side that the modeset
-		 * call has returned.
-		 */
-		dev_dbg(dcp->dev, "%s - wait for modeset", __func__);
-		ret = wait_for_completion_timeout(&cookie->done,
-						  msecs_to_jiffies(8500));
-
-		kref_put(&cookie->refcount, release_wait_cookie);
-
-		if (ret == 0) {
-			dev_info(dcp->dev, "set_digital_out_mode timed out");
-			schedule_work(&dcp->vblank_wq);
-			return;
-		} else if (ret > 0) {
-			dev_dbg(dcp->dev,
-				"set_digital_out_mode finished with %d to spare",
-				jiffies_to_msecs(ret));
-		}
-
-		dcp->valid_mode = true;
-	}
-
 	if (!has_surface && !crtc_state->color_mgmt_changed) {
 		if (crtc_state->enable && crtc_state->active &&
 		    !crtc_state->planes_changed) {

drivers/gpu/drm/apple/iomfb_template.h

@@ -172,6 +172,8 @@ struct DCP_FW_NAME(dcp_map_reg_resp) {
 
 struct apple_dcp;
 
+int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
+			       struct drm_crtc_state *crtc_state);
 void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, struct drm_atomic_state *state);
 void DCP_FW_NAME(iomfb_poweron)(struct apple_dcp *dcp);
 void DCP_FW_NAME(iomfb_poweroff)(struct apple_dcp *dcp);