drm/amd/display: Add support for hw_state logging via debugfs

[Why]

We have logging methods for printing hardware state for newer ASICs
but no way to trigger the log output.

[How]

Add support for triggering the output via writing to a debugfs file
entry. Log output currently goes into dmesg for convenience, but
accessing via a read should be possible later.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Jordan Lazare <Jordan.Lazare@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 ad11dc9..7b857d4 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -480,6 +480,11 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
                goto error;
        }
 
+#if defined(CONFIG_DEBUG_FS)
+       if (dtn_debugfs_init(adev))
+               DRM_ERROR("amdgpu: failed initialize dtn debugfs support.\n");
+#endif
+
        DRM_DEBUG_DRIVER("KMS initialized.\n");
 
        return 0;

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 0d9e410..e79ac1e 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
@@ -720,3 +720,56 @@ int connector_debugfs_init(struct amdgpu_dm_connector *connector)
        return 0;
 }
 
+static ssize_t dtn_log_read(
+       struct file *f,
+       char __user *buf,
+       size_t size,
+       loff_t *pos)
+{
+       /* TODO: Write log output to the user supplied buffer. */
+       return 0;
+}
+
+static ssize_t dtn_log_write(
+       struct file *f,
+       const char __user *buf,
+       size_t size,
+       loff_t *pos)
+{
+       struct amdgpu_device *adev = file_inode(f)->i_private;
+       struct dc *dc = adev->dm.dc;
+
+       /* Write triggers log output via dmesg. */
+       if (size == 0)
+               return 0;
+
+       if (dc->hwss.log_hw_state)
+               dc->hwss.log_hw_state(dc);
+
+       return size;
+}
+
+int dtn_debugfs_init(struct amdgpu_device *adev)
+{
+       static const struct file_operations dtn_log_fops = {
+               .owner = THIS_MODULE,
+               .read = dtn_log_read,
+               .write = dtn_log_write,
+               .llseek = default_llseek
+       };
+
+       struct drm_minor *minor = adev->ddev->primary;
+       struct dentry *root = minor->debugfs_root;
+
+       struct dentry *ent = debugfs_create_file(
+               "amdgpu_dm_dtn_log",
+               0644,
+               root,
+               adev,
+               &dtn_log_fops);
+
+       if (IS_ERR(ent))
+               return PTR_ERR(ent);
+
+       return 0;
+}

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.h
index d9ed1b2..bdef158 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.h
@@ -30,5 +30,6 @@
 #include "amdgpu_dm.h"
 
 int connector_debugfs_init(struct amdgpu_dm_connector *connector);
+int dtn_debugfs_init(struct amdgpu_device *adev);
 
 #endif

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 8403b6a..86b63ce 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -336,14 +336,28 @@ bool dm_helpers_dp_mst_send_payload_allocation(
 }
 
 void dm_dtn_log_begin(struct dc_context *ctx)
-{}
+{
+       pr_info("[dtn begin]\n");
+}
 
 void dm_dtn_log_append_v(struct dc_context *ctx,
-               const char *pMsg, ...)
-{}
+               const char *msg, ...)
+{
+       struct va_format vaf;
+       va_list args;
+
+       va_start(args, msg);
+       vaf.fmt = msg;
+       vaf.va = &args;
+
+       pr_info("%pV", &vaf);
+       va_end(args);
+}
 
 void dm_dtn_log_end(struct dc_context *ctx)
-{}
+{
+       pr_info("[dtn end]\n");
+}
 
 bool dm_helpers_dp_mst_start_top_mgr(
                struct dc_context *ctx,