[Joshua's agent] drm/apple, isp: best-effort software camera indicator (draft, unbooted)

Documentation/devicetree/bindings/display/apple,dcp.yaml

@@ -187,6 +187,16 @@ properties:
       Per-slot enable flags, in slot order. The legacy J700 bootloader
       supplies a single zero to select surface zero instead.
 
+  apple,camera-indicator-surface:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 3
+    description: |
+      Swap slot the kernel reserves for the software camera indicator, a
+      kernel-owned overlay on the internal panel that the camera driver shows
+      while it streams, on a best-effort basis: the camera does not depend on
+      it. The slot must not be enabled in apple,iomfb-surfaces. Userspace cannot
+      use the slot. This is a software indicator, not a privacy guarantee.
+
   apple,power-lut-data-x:
     $ref: /schemas/types.yaml#/definitions/uint8-array
     minItems: 4

Documentation/devicetree/bindings/media/apple,t6050-isp.yaml

@@ -117,6 +117,14 @@ properties:
     description:
       Firmware temporal-filter strength selected for the attached sensor.
 
+  apple,camera-indicator:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Optional. The display coprocessor asked to present the software camera
+      indicator while the camera streams. The request is best-effort and the
+      camera streams whether or not the indicator is shown. The indicator is
+      software, not a privacy guarantee.
+
   sensor-presets:
     type: object
     description:

drivers/gpu/drm/apple/Makefile

@@ -31,14 +31,15 @@ appledrm-$(CONFIG_DRM_APPLE_KUNIT_TEST) += dcp_dropped_swap_test.o
 appledrm-y += iomfb_v26_6.o iomfb_v26_6_link.o j613_dcp_activate.o
 appledrm-y += iomfb_v27.o
 appledrm-y += epic/dpavservep.o
-appledrm-y += plane.o
+appledrm-y += plane.o dcp-indicator.o
 
 
 appledrm-$(CONFIG_TRACING) += trace.o
 
 obj-$(CONFIG_DRM_APPLE) += appledrm.o
 obj-$(CONFIG_DRM_APPLE_KUNIT_TEST) += afk_test.o
 obj-$(CONFIG_DRM_APPLE_KUNIT_TEST) += dcp_backlight_test.o
+obj-$(CONFIG_DRM_APPLE_KUNIT_TEST) += dcp-indicator-test.o
 obj-$(CONFIG_DRM_APPLE_KUNIT_TEST) += dcp-announce-test.o
 
 obj-$(CONFIG_DRM_APPLE_KUNIT_TEST) += afk-service-test.o

drivers/gpu/drm/apple/apple_drv.c

@@ -1173,6 +1173,26 @@ static int apple_probe_per_dcp(struct device *dev,
 		zpos++;
 	}
 
+	if (dcp_data->camera_ind.has_surf) {
+		struct drm_plane *ind_plane;
+
+		ind_plane = apple_plane_init(drm, 1U << num, dcp_data->camera_ind.surf,
+					     supports_l10r, supports_xrgb2101010,
+					     dcp_data->hw.iomfb_method_profile ==
+						     DCP_IOMFB_METHODS_H17G,
+					     DRM_PLANE_TYPE_OVERLAY, false,
+					     supports_premultiplied);
+		if (IS_ERR(ind_plane))
+			return PTR_ERR(ind_plane);
+		ret = drm_plane_create_zpos_immutable_property(ind_plane, zpos++);
+		if (ret)
+			return ret;
+		/* Without its buffer the plane stays reserved and no indicator is shown. */
+		ret = dcp_indicator_attach_plane(dcp_data, drm, ind_plane);
+		if (ret)
+			dev_err(dev, "camera indicator unavailable: %d\n", ret);
+	}
+
 	/*
 	 * Even though we have an overlay plane, we cannot expose it to legacy
 	 * userspace for cursors as we cannot make the same guarantees as ye olde
@@ -1992,6 +2012,7 @@ static bool apple_drm_hold_resume_events(struct apple_drm_private *apple, u32 cr
 
 static void apple_drm_resume_outputs(struct apple_drm_private *apple)
 {
+	struct drm_crtc *crtc;
 	u32 dropped = 0;
 
 	apple->dark_held = false;
@@ -2001,6 +2022,11 @@ static void apple_drm_resume_outputs(struct apple_drm_private *apple)
 	if (dropped && apple_drm_hold_resume_events(apple, dropped))
 		dropped = 0;
 	drm_mode_config_helper_resume(&apple->drm);
+	drm_for_each_crtc(crtc, &apple->drm) {
+		if (t8132_ext_crtc(crtc))
+			continue;
+		dcp_indicator_display_resumed(platform_get_drvdata(to_apple_crtc(crtc)->dcp));
+	}
 	if (dropped)
 		drm_kms_helper_hotplug_event(&apple->drm);
 }