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.l...@amd.com>
---
 drivers/gpu/drm/amd/display/Kconfig           |  2 +
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 82 +++++++++++++++++++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  4 +
 .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 66 ++++++++++++++-
 drivers/gpu/drm/amd/include/amd_shared.h      |  5 ++
 5 files changed, 158 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/Kconfig 
b/drivers/gpu/drm/amd/display/Kconfig
index 11e3f2f3b1..abd3b65643 100644
--- a/drivers/gpu/drm/amd/display/Kconfig
+++ b/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))
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 85f21db6ef..3bd93cc14f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/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"
@@ -2746,6 +2747,54 @@ static void resume_mst_branch_status(struct 
drm_dp_mst_topology_mgr *mgr)
        mutex_unlock(&mgr->lock);
 }
 
+static void hdmi_cec_unset_edid(struct amdgpu_dm_connector *aconnector)
+{
+       struct drm_device *ddev = aconnector->base.dev;
+       struct cec_notifier *n = aconnector->notifier;
+
+       if (!n) {
+               drm_dbg(ddev, "failed to unset edid\n");
+               return;
+       }
+
+       cec_notifier_phys_addr_invalidate(n);
+}
+
+static void hdmi_cec_set_edid(struct amdgpu_dm_connector *aconnector)
+{
+       struct drm_connector *connector = &aconnector->base;
+       struct drm_device *ddev = aconnector->base.dev;
+       struct cec_notifier *n = aconnector->notifier;
+
+       if (!n) {
+               drm_dbg(ddev, "failed to set edid\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;
@@ -3017,6 +3066,8 @@ 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);
@@ -3289,6 +3340,8 @@ 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);
 
@@ -3598,6 +3651,7 @@ 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);
                        }
@@ -3607,6 +3661,7 @@ 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);
@@ -3623,6 +3678,7 @@ 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;
@@ -7042,6 +7098,7 @@ 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);
 }
 
@@ -8278,6 +8335,27 @@ 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
@@ -8341,6 +8419,10 @@ 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);
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 6464a83783..4c1942652b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/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 +1012,6 @@ void dm_free_gpu_mem(struct amdgpu_device *adev,
 
 bool amdgpu_dm_is_headless(struct amdgpu_device *adev);
 
+int amdgpu_dm_initialize_hdmi_connector(struct amdgpu_dm_connector 
*aconnector);
+
 #endif /* __AMDGPU_DM_H__ */
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
index 6a97bb2d91..922f329175 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/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"
@@ -2825,6 +2826,67 @@ static int is_dpia_link_show(struct seq_file *m, void 
*data)
        return 0;
 }
 
+/*
+ * function description: Read out the HDMI-CEC feature status
+ *
+ * Example usage:
+ * cat /sys/kernel/debug/dri/0/HDMI-A-1/hdmi_cec_state
+ */
+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;
+}
+
+/*
+ * function: Enable/Disable HDMI-CEC feature from driver side
+ *
+ * Example usage:
+ * echo 1 > /sys/kernel/debug/dri/0/HDMI-A-1/hdmi_cec_state
+ * echo 0 > /sys/kernel/debug/dri/0/HDMI-A-1/hdmi_cec_state
+ */
+static ssize_t hdmi_cec_state_write(struct file *f, const char __user *buf,
+                                    size_t size, loff_t *pos)
+{
+       char tmp[2];
+       int ret;
+       struct amdgpu_dm_connector *aconnector = file_inode(f)->i_private;
+       struct drm_connector *dconn = &aconnector->base;
+       struct drm_device *ddev = aconnector->base.dev;
+
+       if (size == 0)
+               return -EINVAL;
+
+       if (copy_from_user(tmp, buf, 1)) {
+               drm_dbg_driver(ddev, "Failed to copy user data !\n");
+               return -EFAULT;
+       }
+
+       switch (tmp[0]) {
+       case '0':
+               cec_notifier_conn_unregister(aconnector->notifier);
+               aconnector->notifier = NULL;
+               break;
+       case '1':
+               ret = amdgpu_dm_initialize_hdmi_connector(aconnector);
+               if (ret)
+                       return ret;
+               cec_notifier_set_phys_addr(aconnector->notifier,
+                               dconn->display_info.source_physical_address);
+               break;
+       default:
+               drm_dbg_driver(ddev, "Unsupported param\n");
+               break;
+       }
+
+       return size;
+}
+
 DEFINE_SHOW_ATTRIBUTE(dp_dsc_fec_support);
 DEFINE_SHOW_ATTRIBUTE(dmub_fw_state);
 DEFINE_SHOW_ATTRIBUTE(dmub_tracebuffer);
@@ -2837,6 +2899,7 @@ 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,
@@ -2972,7 +3035,8 @@ 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}
 };
 
 /*
diff --git a/drivers/gpu/drm/amd/include/amd_shared.h 
b/drivers/gpu/drm/amd/include/amd_shared.h
index 98d9e840b0..05bdb4e020 100644
--- a/drivers/gpu/drm/amd/include/amd_shared.h
+++ b/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;
-- 
2.34.1

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