4 files changed, 75 insertions, 14 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index ffbbb454c9e8..8c329c071c62 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -476,7 +476,12 @@ static int __init vc4_drm_register(void)
 	if (ret)
 		return ret;
 
-	return platform_driver_register(&vc4_platform_driver);
+	ret = platform_driver_register(&vc4_platform_driver);
+	if (ret)
+		platform_unregister_drivers(component_drivers,
+					    ARRAY_SIZE(component_drivers));
+
+	return ret;
 }
 
 static void __exit vc4_drm_unregister(void)
@@ -490,6 +495,7 @@ module_init(vc4_drm_register);
 module_exit(vc4_drm_unregister);
 
 MODULE_ALIAS("platform:vc4-drm");
+MODULE_SOFTDEP("pre: snd-soc-hdmi-codec");
 MODULE_DESCRIPTION("Broadcom VC4 DRM Driver");
 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 64f9feabf43e..470432c8fd70 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -349,27 +349,40 @@ static int vc4_hdmi_reset_link(struct drm_connector *connector,
 	if (!crtc_state->active)
 		return 0;
 
-	if (!vc4_hdmi_supports_scrambling(encoder))
+	mutex_lock(&vc4_hdmi->mutex);
+
+	if (!vc4_hdmi_supports_scrambling(encoder)) {
+		mutex_unlock(&vc4_hdmi->mutex);
 		return 0;
+	}
 
 	scrambling_needed = vc4_hdmi_mode_needs_scrambling(&vc4_hdmi->saved_adjusted_mode,
 							   vc4_hdmi->output_bpc,
 							   vc4_hdmi->output_format);
-	if (!scrambling_needed)
+	if (!scrambling_needed) {
+		mutex_unlock(&vc4_hdmi->mutex);
 		return 0;
+	}
 
 	if (conn_state->commit &&
-	    !try_wait_for_completion(&conn_state->commit->hw_done))
+	    !try_wait_for_completion(&conn_state->commit->hw_done)) {
+		mutex_unlock(&vc4_hdmi->mutex);
 		return 0;
+	}
 
 	ret = drm_scdc_readb(connector->ddc, SCDC_TMDS_CONFIG, &config);
 	if (ret < 0) {
 		drm_err(drm, "Failed to read TMDS config: %d\n", ret);
+		mutex_unlock(&vc4_hdmi->mutex);
 		return 0;
 	}
 
-	if (!!(config & SCDC_SCRAMBLING_ENABLE) == scrambling_needed)
+	if (!!(config & SCDC_SCRAMBLING_ENABLE) == scrambling_needed) {
+		mutex_unlock(&vc4_hdmi->mutex);
 		return 0;
+	}
+
+	mutex_unlock(&vc4_hdmi->mutex);
 
 	/*
 	 * HDMI 2.0 says that one should not send scrambled data
@@ -397,9 +410,8 @@ static void vc4_hdmi_handle_hotplug(struct vc4_hdmi *vc4_hdmi,
 	 * .adap_enable, which leads to that funtion being called with
 	 * our mutex held.
 	 *
-	 * A similar situation occurs with
-	 * drm_atomic_helper_connector_hdmi_reset_link() that will call
-	 * into our KMS hooks if the scrambling was enabled.
+	 * A similar situation occurs with vc4_hdmi_reset_link() that
+	 * will call into our KMS hooks if the scrambling was enabled.
 	 *
 	 * Concurrency isn't an issue at the moment since we don't share
 	 * any state with any of the other frameworks so we can ignore
@@ -3160,9 +3172,16 @@ static int vc4_hdmi_init_resources(struct drm_device *drm,
 		DRM_ERROR("Failed to get HDMI state machine clock\n");
 		return PTR_ERR(vc4_hdmi->hsm_clock);
 	}
+
 	vc4_hdmi->audio_clock = vc4_hdmi->hsm_clock;
 	vc4_hdmi->cec_clock = vc4_hdmi->hsm_clock;
 
+	vc4_hdmi->hsm_rpm_clock = devm_clk_get(dev, "hdmi");
+	if (IS_ERR(vc4_hdmi->hsm_rpm_clock)) {
+		DRM_ERROR("Failed to get HDMI state machine clock\n");
+		return PTR_ERR(vc4_hdmi->hsm_rpm_clock);
+	}
+
 	return 0;
 }
 
@@ -3245,6 +3264,12 @@ static int vc5_hdmi_init_resources(struct drm_device *drm,
 		return PTR_ERR(vc4_hdmi->hsm_clock);
 	}
 
+	vc4_hdmi->hsm_rpm_clock = devm_clk_get(dev, "hdmi");
+	if (IS_ERR(vc4_hdmi->hsm_rpm_clock)) {
+		DRM_ERROR("Failed to get HDMI state machine clock\n");
+		return PTR_ERR(vc4_hdmi->hsm_rpm_clock);
+	}
+
 	vc4_hdmi->pixel_bvb_clock = devm_clk_get(dev, "bvb");
 	if (IS_ERR(vc4_hdmi->pixel_bvb_clock)) {
 		DRM_ERROR("Failed to get pixel bvb clock\n");
@@ -3308,7 +3333,7 @@ static int vc4_hdmi_runtime_suspend(struct device *dev)
 {
 	struct vc4_hdmi *vc4_hdmi = dev_get_drvdata(dev);
 
-	clk_disable_unprepare(vc4_hdmi->hsm_clock);
+	clk_disable_unprepare(vc4_hdmi->hsm_rpm_clock);
 
 	return 0;
 }
@@ -3318,12 +3343,37 @@ static int vc4_hdmi_runtime_resume(struct device *dev)
 	struct vc4_hdmi *vc4_hdmi = dev_get_drvdata(dev);
 	unsigned long __maybe_unused flags;
 	u32 __maybe_unused value;
+	unsigned long rate;
 	int ret;
 
-	ret = clk_prepare_enable(vc4_hdmi->hsm_clock);
+	/*
+	 * The HSM clock is in the HDMI power domain, so we need to set
+	 * its frequency while the power domain is active so that it
+	 * keeps its rate.
+	 */
+	ret = clk_set_min_rate(vc4_hdmi->hsm_rpm_clock, HSM_MIN_CLOCK_FREQ);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(vc4_hdmi->hsm_rpm_clock);
 	if (ret)
 		return ret;
 
+	/*
+	 * Whenever the RaspberryPi boots without an HDMI monitor
+	 * plugged in, the firmware won't have initialized the HSM clock
+	 * rate and it will be reported as 0.
+	 *
+	 * If we try to access a register of the controller in such a
+	 * case, it will lead to a silent CPU stall. Let's make sure we
+	 * prevent such a case.
+	 */
+	rate = clk_get_rate(vc4_hdmi->hsm_rpm_clock);
+	if (!rate) {
+		ret = -EINVAL;
+		goto err_disable_clk;
+	}
+
 	if (vc4_hdmi->variant->reset)
 		vc4_hdmi->variant->reset(vc4_hdmi);
 
@@ -3345,6 +3395,10 @@ static int vc4_hdmi_runtime_resume(struct device *dev)
 #endif
 
 	return 0;
+
+err_disable_clk:
+	clk_disable_unprepare(vc4_hdmi->hsm_clock);
+	return ret;
 }
 
 static void vc4_hdmi_put_ddc_device(void *ptr)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index db823efb2563..1ad8e8c377e2 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -172,6 +172,7 @@ struct vc4_hdmi {
 	struct clk *cec_clock;
 	struct clk *pixel_clock;
 	struct clk *hsm_clock;
+	struct clk *hsm_rpm_clock;
 	struct clk *audio_clock;
 	struct clk *pixel_bvb_clock;
 
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 4419e810103d..0a6347c05df4 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -197,8 +197,8 @@ vc4_hvs_get_new_global_state(struct drm_atomic_state *state)
 	struct drm_private_state *priv_state;
 
 	priv_state = drm_atomic_get_new_private_obj_state(state, &vc4->hvs_channels);
-	if (IS_ERR(priv_state))
-		return ERR_CAST(priv_state);
+	if (!priv_state)
+		return ERR_PTR(-EINVAL);
 
 	return to_vc4_hvs_state(priv_state);
 }
@@ -210,8 +210,8 @@ vc4_hvs_get_old_global_state(struct drm_atomic_state *state)
 	struct drm_private_state *priv_state;
 
 	priv_state = drm_atomic_get_old_private_obj_state(state, &vc4->hvs_channels);
-	if (IS_ERR(priv_state))
-		return ERR_CAST(priv_state);
+	if (!priv_state)
+		return ERR_PTR(-EINVAL);
 
 	return to_vc4_hvs_state(priv_state);
 }