drm/i915: Debugfs support for GuC logging control

This patch provides debugfs interface i915_guc_output_control for
on the fly enabling/disabling of logging in GuC firmware and controlling
the verbosity level of logs.
The value written to the file, should have bit 0 set to enable logging and
bits 4-7 should contain the verbosity info.

v2: Add a forceful flush, to collect left over logs, on disabling logging.
    Useful for Validation.

v3: Besides minor cleanup, implement read method for the debugfs file and
    set the guc_log_level to -1 when logging is disabled. (Tvrtko)

v4: Minor cleanup & rebase. (Tvrtko)

v5:
- Lock struct_mutex after the NULL check for guc log buffer vma. (Chris)
- Rebase.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 40 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index e24f69cdc69b..be92efe3453f 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2548,6 +2548,44 @@ static int i915_guc_log_dump(struct seq_file *m, void *data)
 	return 0;
 }
 
+static int i915_guc_log_control_get(void *data, u64 *val)
+{
+	struct drm_device *dev = data;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+
+	if (!dev_priv->guc.log.vma)
+		return -EINVAL;
+
+	*val = i915.guc_log_level;
+
+	return 0;
+}
+
+static int i915_guc_log_control_set(void *data, u64 val)
+{
+	struct drm_device *dev = data;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	int ret;
+
+	if (!dev_priv->guc.log.vma)
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
+
+	intel_runtime_pm_get(dev_priv);
+	ret = i915_guc_log_control(dev_priv, val);
+	intel_runtime_pm_put(dev_priv);
+
+	mutex_unlock(&dev->struct_mutex);
+	return ret;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(i915_guc_log_control_fops,
+			i915_guc_log_control_get, i915_guc_log_control_set,
+			"%lld\n");
+
 static int i915_edp_psr_status(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -5454,7 +5492,8 @@ static const struct i915_debugfs_files {
 	{"i915_fbc_false_color", &i915_fbc_fc_fops},
 	{"i915_dp_test_data", &i915_displayport_test_data_fops},
 	{"i915_dp_test_type", &i915_displayport_test_type_fops},
-	{"i915_dp_test_active", &i915_displayport_test_active_fops}
+	{"i915_dp_test_active", &i915_displayport_test_active_fops},
+	{"i915_guc_log_control", &i915_guc_log_control_fops}
 };
 
 void intel_display_crc_init(struct drm_i915_private *dev_priv)