drm/amd/display: add CEC notifier to amdgpu driver

This patch adds the cec_notifier feature to amdgpu driver.
The changes will allow amdgpu driver code to notify EDID
and HPD changes to an eventual CEC adapter.

Signed-off-by: Kun Liu <Kun.Liu2@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/Kconfig

@@ -8,6 +8,8 @@ config DRM_AMD_DC
 	bool "AMD DC - Enable new display engine"
 	default y
 	depends on BROKEN || !CC_IS_CLANG || ARM64 || LOONGARCH || RISCV || SPARC64 || X86_64
+	select CEC_CORE
+	select CEC_NOTIFIER
 	select SND_HDA_COMPONENT if SND_HDA_CORE
 	# !CC_IS_CLANG: https://github.com/ClangBuiltLinux/linux/issues/1752
 	select DRM_AMD_DC_FP if ARCH_HAS_KERNEL_FPU_SUPPORT && !(CC_IS_CLANG && (ARM64 || LOONGARCH || RISCV))

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -97,6 +97,7 @@
 #include <drm/drm_audio_component.h>
 #include <drm/drm_gem_atomic_helper.h>
 
+#include <media/cec-notifier.h>
 #include <acpi/video.h>
 
 #include "ivsrcid/dcn/irqsrcs_dcn_1_0.h"
@@ -2751,6 +2752,48 @@ static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr)
 	mutex_unlock(&mgr->lock);
 }
 
+void hdmi_cec_unset_edid(struct amdgpu_dm_connector *aconnector)
+{
+	struct cec_notifier *n = aconnector->notifier;
+
+	if (!n)
+		return;
+
+	cec_notifier_phys_addr_invalidate(n);
+}
+
+void hdmi_cec_set_edid(struct amdgpu_dm_connector *aconnector)
+{
+	struct drm_connector *connector = &aconnector->base;
+	struct cec_notifier *n = aconnector->notifier;
+
+	if (!n)
+		return;
+
+	cec_notifier_set_phys_addr(n,
+				   connector->display_info.source_physical_address);
+}
+
+static void s3_handle_hdmi_cec(struct drm_device *ddev, bool suspend)
+{
+	struct amdgpu_dm_connector *aconnector;
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+
+	drm_connector_list_iter_begin(ddev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
+			continue;
+
+		aconnector = to_amdgpu_dm_connector(connector);
+		if (suspend)
+			hdmi_cec_unset_edid(aconnector);
+		else
+			hdmi_cec_set_edid(aconnector);
+	}
+	drm_connector_list_iter_end(&conn_iter);
+}
+
 static void s3_handle_mst(struct drm_device *dev, bool suspend)
 {
 	struct amdgpu_dm_connector *aconnector;
@@ -3022,6 +3065,8 @@ static int dm_suspend(struct amdgpu_ip_block *ip_block)
 	if (IS_ERR(adev->dm.cached_state))
 		return PTR_ERR(adev->dm.cached_state);
 
+	s3_handle_hdmi_cec(adev_to_drm(adev), true);
+
 	s3_handle_mst(adev_to_drm(adev), true);
 
 	amdgpu_dm_irq_suspend(adev);
@@ -3294,6 +3339,8 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
 	 */
 	amdgpu_dm_irq_resume_early(adev);
 
+	s3_handle_hdmi_cec(ddev, false);
+
 	/* On resume we need to rewrite the MSTM control bits to enable MST*/
 	s3_handle_mst(ddev, false);
 
@@ -3603,6 +3650,7 @@ void amdgpu_dm_update_connector_after_detect(
 		dc_sink_retain(aconnector->dc_sink);
 		if (sink->dc_edid.length == 0) {
 			aconnector->drm_edid = NULL;
+			hdmi_cec_unset_edid(aconnector);
 			if (aconnector->dc_link->aux_mode) {
 				drm_dp_cec_unset_edid(&aconnector->dm_dp_aux.aux);
 			}
@@ -3612,6 +3660,7 @@ void amdgpu_dm_update_connector_after_detect(
 			aconnector->drm_edid = drm_edid_alloc(edid, sink->dc_edid.length);
 			drm_edid_connector_update(connector, aconnector->drm_edid);
 
+			hdmi_cec_set_edid(aconnector);
 			if (aconnector->dc_link->aux_mode)
 				drm_dp_cec_attach(&aconnector->dm_dp_aux.aux,
 						  connector->display_info.source_physical_address);
@@ -3628,6 +3677,7 @@ void amdgpu_dm_update_connector_after_detect(
 		amdgpu_dm_update_freesync_caps(connector, aconnector->drm_edid);
 		update_connector_ext_caps(aconnector);
 	} else {
+		hdmi_cec_unset_edid(aconnector);
 		drm_dp_cec_unset_edid(&aconnector->dm_dp_aux.aux);
 		amdgpu_dm_update_freesync_caps(connector, NULL);
 		aconnector->num_modes = 0;
@@ -7044,6 +7094,7 @@ static void amdgpu_dm_connector_unregister(struct drm_connector *connector)
 	if (amdgpu_dm_should_create_sysfs(amdgpu_dm_connector))
 		sysfs_remove_group(&connector->kdev->kobj, &amdgpu_group);
 
+	cec_notifier_conn_unregister(amdgpu_dm_connector->notifier);
 	drm_dp_aux_unregister(&amdgpu_dm_connector->dm_dp_aux.aux);
 }
 
@@ -8280,6 +8331,27 @@ create_i2c(struct ddc_service *ddc_service,
 	return i2c;
 }
 
+int amdgpu_dm_initialize_hdmi_connector(struct amdgpu_dm_connector *aconnector)
+{
+	struct cec_connector_info conn_info;
+	struct drm_device *ddev = aconnector->base.dev;
+	struct device *hdmi_dev = ddev->dev;
+
+	if (amdgpu_dc_debug_mask & DC_DISABLE_HDMI_CEC) {
+		drm_info(ddev, "HDMI-CEC feature masked\n");
+		return -EINVAL;
+	}
+
+	cec_fill_conn_info_from_drm(&conn_info, &aconnector->base);
+	aconnector->notifier =
+		cec_notifier_conn_register(hdmi_dev, NULL, &conn_info);
+	if (!aconnector->notifier) {
+		drm_err(ddev, "Failed to create cec notifier\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
 
 /*
  * Note: this function assumes that dc_link_detect() was called for the
@@ -8343,6 +8415,10 @@ static int amdgpu_dm_connector_init(struct amdgpu_display_manager *dm,
 	drm_connector_attach_encoder(
 		&aconnector->base, &aencoder->base);
 
+	if (connector_type == DRM_MODE_CONNECTOR_HDMIA ||
+	    connector_type == DRM_MODE_CONNECTOR_HDMIB)
+		amdgpu_dm_initialize_hdmi_connector(aconnector);
+
 	if (connector_type == DRM_MODE_CONNECTOR_DisplayPort
 		|| connector_type == DRM_MODE_CONNECTOR_eDP)
 		amdgpu_dm_initialize_dp_connector(dm, aconnector, link->link_index);

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

@@ -671,6 +671,8 @@ struct amdgpu_dm_connector {
 	uint32_t connector_id;
 	int bl_idx;
 
+	struct cec_notifier *notifier;
+
 	/* we need to mind the EDID between detect
 	   and get modes due to analog/digital/tvencoder */
 	const struct drm_edid *drm_edid;
@@ -1010,4 +1012,8 @@ void dm_free_gpu_mem(struct amdgpu_device *adev,
 
 bool amdgpu_dm_is_headless(struct amdgpu_device *adev);
 
+void hdmi_cec_set_edid(struct amdgpu_dm_connector *aconnector);
+void hdmi_cec_unset_edid(struct amdgpu_dm_connector *aconnector);
+int amdgpu_dm_initialize_hdmi_connector(struct amdgpu_dm_connector *aconnector);
+
 #endif /* __AMDGPU_DM_H__ */

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

@@ -25,6 +25,7 @@
 
 #include <linux/string_helpers.h>
 #include <linux/uaccess.h>
+#include <media/cec-notifier.h>
 
 #include "dc.h"
 #include "amdgpu.h"
@@ -2848,6 +2849,67 @@ static int is_dpia_link_show(struct seq_file *m, void *data)
 	return 0;
 }
 
+/**
+ * hdmi_cec_state_show - Read out the HDMI-CEC feature status
+ * @m: sequence file.
+ * @data: unused.
+ *
+ * Return 0 on success
+ */
+static int hdmi_cec_state_show(struct seq_file *m, void *data)
+{
+	struct drm_connector *connector = m->private;
+	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+
+	seq_printf(m, "%s:%d\n", connector->name, connector->base.id);
+	seq_printf(m, "HDMI-CEC status: %d\n", aconnector->notifier ? 1 : 0);
+
+	return 0;
+}
+
+/**
+ * hdmi_cec_state_write - Enable/Disable HDMI-CEC feature from driver side
+ * @f: file structure.
+ * @buf: userspace buffer. set to '1' to enable; '0' to disable cec feature.
+ * @size: size of buffer from userpsace.
+ * @pos: unused.
+ *
+ * Return size on success, error code on failure
+ */
+static ssize_t hdmi_cec_state_write(struct file *f, const char __user *buf,
+				    size_t size, loff_t *pos)
+{
+	int ret;
+	bool enable;
+	struct amdgpu_dm_connector *aconnector = file_inode(f)->i_private;
+	struct drm_device *ddev = aconnector->base.dev;
+
+	if (size == 0)
+		return -EINVAL;
+
+	ret = kstrtobool_from_user(buf, size, &enable);
+	if (ret) {
+		drm_dbg_driver(ddev, "invalid user data !\n");
+		return ret;
+	}
+
+	if (enable) {
+		if (aconnector->notifier)
+			return -EINVAL;
+		ret = amdgpu_dm_initialize_hdmi_connector(aconnector);
+		if (ret)
+			return ret;
+		hdmi_cec_set_edid(aconnector);
+	} else {
+		if (!aconnector->notifier)
+			return -EINVAL;
+		cec_notifier_conn_unregister(aconnector->notifier);
+		aconnector->notifier = NULL;
+	}
+
+	return size;
+}
+
 DEFINE_SHOW_ATTRIBUTE(dp_dsc_fec_support);
 DEFINE_SHOW_ATTRIBUTE(dmub_fw_state);
 DEFINE_SHOW_ATTRIBUTE(dmub_tracebuffer);
@@ -2860,6 +2922,7 @@ DEFINE_SHOW_ATTRIBUTE(psr_capability);
 DEFINE_SHOW_ATTRIBUTE(dp_is_mst_connector);
 DEFINE_SHOW_ATTRIBUTE(dp_mst_progress_status);
 DEFINE_SHOW_ATTRIBUTE(is_dpia_link);
+DEFINE_SHOW_STORE_ATTRIBUTE(hdmi_cec_state);
 
 static const struct file_operations dp_dsc_clock_en_debugfs_fops = {
 	.owner = THIS_MODULE,
@@ -2995,7 +3058,8 @@ static const struct {
 	char *name;
 	const struct file_operations *fops;
 } hdmi_debugfs_entries[] = {
-		{"hdcp_sink_capability", &hdcp_sink_capability_fops}
+		{"hdcp_sink_capability", &hdcp_sink_capability_fops},
+		{"hdmi_cec_state", &hdmi_cec_state_fops}
 };
 
 /*

drivers/gpu/drm/amd/include/amd_shared.h

@@ -344,6 +344,11 @@ enum DC_DEBUG_MASK {
 	 * eDP display from ACPI _DDC method.
 	 */
 	DC_DISABLE_ACPI_EDID = 0x8000,
+
+	/*
+	 * @DC_DISABLE_HDMI_CEC: If set, disable HDMI-CEC feature in amdgpu driver.
+	 */
+	DC_DISABLE_HDMI_CEC = 0x10000,
 };
 
 enum amd_dpm_forced_level;