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.comSigned-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

+// 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

+/* 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,

drivers/gpu/drm/imagination/pvr_params.c

+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#include "pvr_params.h"
+
+#include <linux/cache.h>
+#include <linux/moduleparam.h>
+
+static struct pvr_device_params pvr_device_param_defaults __read_mostly = {
+#define X(type_, name_, value_, desc_, ...) .name_ = (value_),
+	PVR_DEVICE_PARAMS
+#undef X
+};
+
+#define PVR_DEVICE_PARAM_NAMED(name_, type_, desc_) \
+	module_param_named(name_, pvr_device_param_defaults.name_, type_, \
+			   0400);                                         \
+	MODULE_PARM_DESC(name_, desc_);
+
+/*
+ * This list of defines must contain every type specified in "pvr_params.h" as
+ * ``PVR_PARAM_TYPE_*_C``.
+ */
+#define PVR_PARAM_TYPE_X32_MODPARAM uint
+
+#define X(type_, name_, value_, desc_, ...) \
+	PVR_DEVICE_PARAM_NAMED(name_, PVR_PARAM_TYPE_##type_##_MODPARAM, desc_);
+PVR_DEVICE_PARAMS
+#undef X
+
+int
+pvr_device_params_init(struct pvr_device_params *params)
+{
+	/*
+	 * If heap-allocated parameters are added in the future (e.g.
+	 * modparam's charp type), they must be handled specially here (via
+	 * kstrdup() in the case of charp). Since that's not necessary yet,
+	 * a straight copy will do for now. This change will also require a
+	 * pvr_device_params_fini() function to free any heap-allocated copies.
+	 */
+
+	*params = pvr_device_param_defaults;
+
+	return 0;
+}
+
+#if defined(CONFIG_DEBUG_FS)
+#include "pvr_device.h"
+
+#include <linux/dcache.h>
+#include <linux/debugfs.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/stddef.h>
+
+/*
+ * This list of defines must contain every type specified in "pvr_params.h" as
+ * ``PVR_PARAM_TYPE_*_C``.
+ */
+#define PVR_PARAM_TYPE_X32_FMT "0x%08llx"
+
+#define X_SET(name_, mode_) X_SET_##mode_(name_)
+#define X_SET_DEF(name_, update_, mode_) X_SET_DEF_##mode_(name_, update_)
+
+#define X_SET_RO(name_) NULL
+#define X_SET_RW(name_) __pvr_device_param_##name_##set
+
+#define X_SET_DEF_RO(name_, update_)
+#define X_SET_DEF_RW(name_, update_)                                    \
+	static int                                                      \
+	X_SET_RW(name_)(void *data, u64 val)                            \
+	{                                                               \
+		struct pvr_device *pvr_dev = data;                      \
+		/* This is not just (update_) to suppress -Waddress. */ \
+		if ((void *)(update_) != NULL)                          \
+			(update_)(pvr_dev, pvr_dev->params.name_, val); \
+		pvr_dev->params.name_ = val;                            \
+		return 0;                                               \
+	}
+
+#define X(type_, name_, value_, desc_, mode_, update_)                     \
+	static int                                                         \
+	__pvr_device_param_##name_##_get(void *data, u64 *val)             \
+	{                                                                  \
+		struct pvr_device *pvr_dev = data;                         \
+		*val = pvr_dev->params.name_;                              \
+		return 0;                                                  \
+	}                                                                  \
+	X_SET_DEF(name_, update_, mode_)                                   \
+	static int                                                         \
+	__pvr_device_param_##name_##_open(struct inode *inode,             \
+					  struct file *file)               \
+	{                                                                  \
+		__simple_attr_check_format(PVR_PARAM_TYPE_##type_##_FMT,   \
+					   0ull);                          \
+		return simple_attr_open(inode, file,                       \
+					__pvr_device_param_##name_##_get,  \
+					X_SET(name_, mode_),               \
+					PVR_PARAM_TYPE_##type_##_FMT);     \
+	}
+PVR_DEVICE_PARAMS
+#undef X
+
+#undef X_SET
+#undef X_SET_RO
+#undef X_SET_RW
+#undef X_SET_DEF
+#undef X_SET_DEF_RO
+#undef X_SET_DEF_RW
+
+static struct {
+#define X(type_, name_, value_, desc_, mode_, update_) \
+	const struct file_operations name_;
+	PVR_DEVICE_PARAMS
+#undef X
+} pvr_device_param_debugfs_fops = {
+#define X(type_, name_, value_, desc_, mode_, update_)     \
+	.name_ = {                                         \
+		.owner = THIS_MODULE,                      \
+		.open = __pvr_device_param_##name_##_open, \
+		.release = simple_attr_release,            \
+		.read = simple_attr_read,                  \
+		.write = simple_attr_write,                \
+		.llseek = generic_file_llseek,             \
+	},
+	PVR_DEVICE_PARAMS
+#undef X
+};
+
+void
+pvr_params_debugfs_init(struct pvr_device *pvr_dev, struct dentry *dir)
+{
+#define X_MODE(mode_) X_MODE_##mode_
+#define X_MODE_RO 0400
+#define X_MODE_RW 0600
+
+#define X(type_, name_, value_, desc_, mode_, update_)             \
+	debugfs_create_file(#name_, X_MODE(mode_), dir, pvr_dev,   \
+			    &pvr_device_param_debugfs_fops.name_);
+	PVR_DEVICE_PARAMS
+#undef X
+
+#undef X_MODE
+#undef X_MODE_RO
+#undef X_MODE_RW
+}
+#endif

drivers/gpu/drm/imagination/pvr_params.h

+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#ifndef PVR_PARAMS_H
+#define PVR_PARAMS_H
+
+#include "pvr_rogue_fwif.h"
+
+#include <linux/cache.h>
+#include <linux/compiler_attributes.h>
+
+/*
+ * This is the definitive list of types allowed in the definition of
+ * %PVR_DEVICE_PARAMS.
+ */
+#define PVR_PARAM_TYPE_X32_C u32
+
+/*
+ * This macro defines all device-specific parameters; that is parameters which
+ * are set independently per device.
+ *
+ * The X-macro accepts the following arguments. Arguments marked with [debugfs]
+ * are ignored when debugfs is disabled; values used for these arguments may
+ * safely be gated behind CONFIG_DEBUG_FS.
+ *
+ * @type_: The definitive list of allowed values is PVR_PARAM_TYPE_*_C.
+ * @name_: Name of the parameter. This is used both as the field name in C and
+ *         stringified as the parameter name.
+ * @value_: Initial/default value.
+ * @desc_: String literal used as help text to describe the usage of this
+ *         parameter.
+ * @mode_: [debugfs] One of {RO,RW}. The access mode of the debugfs entry for
+ *         this parameter.
+ * @update_: [debugfs] When debugfs support is enabled, parameters may be
+ *           updated at runtime. When this happens, this function will be
+ *           called to allow changes to propagate. The signature of this
+ *           function is:
+ *
+ *              void (*)(struct pvr_device *pvr_dev, T old_val, T new_val)
+ *
+ *           Where T is the C type associated with @type_.
+ *
+ *           If @mode_ does not allow write access, this function will never be
+ *           called. In this case, or if no update callback is required, you
+ *           should specify NULL for this argument.
+ */
+#define PVR_DEVICE_PARAMS                                                    \
+	X(X32, fw_trace_mask, ROGUE_FWIF_LOG_TYPE_NONE,                      \
+	  "Enable FW trace for the specified groups. Specifying 0 disables " \
+	  "all FW tracing.",                                                 \
+	  RW, pvr_fw_trace_mask_update)
+
+struct pvr_device_params {
+#define X(type_, name_, value_, desc_, ...) \
+	PVR_PARAM_TYPE_##type_##_C name_;
+	PVR_DEVICE_PARAMS
+#undef X
+};
+
+int pvr_device_params_init(struct pvr_device_params *params);
+
+#if defined(CONFIG_DEBUG_FS)
+/* Forward declaration from "pvr_device.h". */
+struct pvr_device;
+
+/* Forward declaration from <linux/dcache.h>. */
+struct dentry;
+
+void pvr_params_debugfs_init(struct pvr_device *pvr_dev, struct dentry *dir);
+#endif /* defined(CONFIG_DEBUG_FS) */
+
+#endif /* PVR_PARAMS_H */