drm/imagination: Add firmware trace to debugfs

Firmware trace is exposed at /sys/debug/dri/<dev_nr>/pvr_fw/trace_0.
Trace is enabled via the group mask at
/sys/debug/dri/<dev_nr>/pvr_params/fw_trace_mask.

Changes since v8:
- Corrected license identifiers

Changes since v3:
- Use drm_dev_{enter,exit}

Co-developed-by: Matt Coster <matt.coster@imgtec.com>
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
Signed-off-by: Sarah Walker <sarah.walker@imgtec.com>
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Link: https://lore.kernel.org/r/009cf9fee347fa96c8a665dc368fc54a5ffceff0.1700668843.git.donald.robson@imgtec.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/gpu/drm/imagination/pvr_debugfs.c b/drivers/gpu/drm/imagination/pvr_debugfs.c
new file mode 100644
index 000000000000..6b77c9b4bde8
--- /dev/null
+++ b/drivers/gpu/drm/imagination/pvr_debugfs.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#include "pvr_debugfs.h"
+
+#include "pvr_device.h"
+#include "pvr_fw_trace.h"
+#include "pvr_params.h"
+
+#include <linux/dcache.h>
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_file.h>
+#include <drm/drm_print.h>
+
+static const struct pvr_debugfs_entry pvr_debugfs_entries[] = {
+	{"pvr_params", pvr_params_debugfs_init},
+	{"pvr_fw", pvr_fw_trace_debugfs_init},
+};
+
+void
+pvr_debugfs_init(struct drm_minor *minor)
+{
+	struct drm_device *drm_dev = minor->dev;
+	struct pvr_device *pvr_dev = to_pvr_device(drm_dev);
+	struct dentry *root = minor->debugfs_root;
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(pvr_debugfs_entries); ++i) {
+		const struct pvr_debugfs_entry *entry = &pvr_debugfs_entries[i];
+		struct dentry *dir;
+
+		dir = debugfs_create_dir(entry->name, root);
+		if (IS_ERR(dir)) {
+			drm_warn(drm_dev,
+				 "failed to create debugfs dir '%s' (err=%d)",
+				 entry->name, (int)PTR_ERR(dir));
+			continue;
+		}
+
+		entry->init(pvr_dev, dir);
+	}
+}
+
+/*
+ * Since all entries are created under &drm_minor->debugfs_root, there's no
+ * need for a pvr_debugfs_fini() as DRM will clean up everything under its root
+ * automatically.
+ */