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>

drivers/gpu/drm/imagination/Makefile

@@ -20,6 +20,7 @@ powervr-y := \
 	pvr_hwrt.o \
 	pvr_job.o \
 	pvr_mmu.o \
+	pvr_params.o \
 	pvr_power.o \
 	pvr_queue.o \
 	pvr_stream.o \
@@ -28,4 +29,7 @@ powervr-y := \
 	pvr_vm.o \
 	pvr_vm_mips.o
 
+powervr-$(CONFIG_DEBUG_FS) += \
+	pvr_debugfs.o
+
 obj-$(CONFIG_DRM_POWERVR) += powervr.o

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.
+ */

drivers/gpu/drm/imagination/pvr_debugfs.h

@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#ifndef PVR_DEBUGFS_H
+#define PVR_DEBUGFS_H
+
+/* Forward declaration from <drm/drm_drv.h>. */
+struct drm_minor;
+
+#if defined(CONFIG_DEBUG_FS)
+/* Forward declaration from "pvr_device.h". */
+struct pvr_device;
+
+/* Forward declaration from <linux/dcache.h>. */
+struct dentry;
+
+struct pvr_debugfs_entry {
+	const char *name;
+	void (*init)(struct pvr_device *pvr_dev, struct dentry *dir);
+};
+
+void pvr_debugfs_init(struct drm_minor *minor);
+#else /* defined(CONFIG_DEBUG_FS) */
+#include <linux/compiler_attributes.h>
+
+static __always_inline void pvr_debugfs_init(struct drm_minor *minor) {}
+#endif /* defined(CONFIG_DEBUG_FS) */
+
+#endif /* PVR_DEBUGFS_H */

drivers/gpu/drm/imagination/pvr_device.c

@@ -5,6 +5,7 @@
 #include "pvr_device_info.h"
 
 #include "pvr_fw.h"
+#include "pvr_params.h"
 #include "pvr_power.h"
 #include "pvr_queue.h"
 #include "pvr_rogue_cr_defs.h"
@@ -495,6 +496,14 @@ pvr_device_init(struct pvr_device *pvr_dev)
 	struct device *dev = drm_dev->dev;
 	int err;
 
+	/*
+	 * Setup device parameters. We do this first in case other steps
+	 * depend on them.
+	 */
+	err = pvr_device_params_init(&pvr_dev->params);
+	if (err)
+		return err;
+
 	/* Enable and initialize clocks required for the device to operate. */
 	err = pvr_device_clk_init(pvr_dev);
 	if (err)

drivers/gpu/drm/imagination/pvr_device.h

@@ -7,6 +7,7 @@
 #include "pvr_ccb.h"
 #include "pvr_device_info.h"
 #include "pvr_fw.h"
+#include "pvr_params.h"
 #include "pvr_rogue_fwif_stream.h"
 #include "pvr_stream.h"
 
@@ -148,6 +149,15 @@ struct pvr_device {
 	/** @fw_dev: Firmware related data. */
 	struct pvr_fw_device fw_dev;
 
+	/**
+	 * @params: Device-specific parameters.
+	 *
+	 *          The values of these parameters are initialized from the
+	 *          defaults specified as module parameters. They may be
+	 *          modified at runtime via debugfs (if enabled).
+	 */
+	struct pvr_device_params params;
+
 	/** @stream_musthave_quirks: Bit array of "must-have" quirks for stream commands. */
 	u32 stream_musthave_quirks[PVR_STREAM_TYPE_MAX][PVR_STREAM_EXTHDR_TYPE_MAX];
 

drivers/gpu/drm/imagination/pvr_drv.c

@@ -2,6 +2,7 @@
 /* Copyright (c) 2023 Imagination Technologies Ltd. */
 
 #include "pvr_context.h"
+#include "pvr_debugfs.h"
 #include "pvr_device.h"
 #include "pvr_drv.h"
 #include "pvr_free_list.h"
@@ -1377,6 +1378,9 @@ static struct drm_driver pvr_drm_driver = {
 	.ioctls = pvr_drm_driver_ioctls,
 	.num_ioctls = ARRAY_SIZE(pvr_drm_driver_ioctls),
 	.fops = &pvr_drm_driver_fops,
+#if defined(CONFIG_DEBUG_FS)
+	.debugfs_init = pvr_debugfs_init,
+#endif
 
 	.name = PVR_DRIVER_NAME,
 	.desc = PVR_DRIVER_DESC,