drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (c) 2014 Raspberry Pi (Trading) Ltd. All rights reserved.
 * Copyright (c) 2010-2012 Broadcom. All rights reserved.
 */

#include <linux/debugfs.h>
#include "vchiq_core.h"
#include "vchiq_arm.h"
#include "vchiq_debugfs.h"

#ifdef CONFIG_DEBUG_FS

#define DEBUGFS_WRITE_BUF_SIZE 256

/* Global 'vchiq' debugfs and clients entry used by all instances */
static struct dentry *vchiq_dbg_dir;
static struct dentry *vchiq_dbg_clients;

static int debugfs_usecount_show(struct seq_file *f, void *offset)
{
	struct vchiq_instance *instance = f->private;
	int use_count;

	use_count = vchiq_instance_get_use_count(instance);
	seq_printf(f, "%d\n", use_count);

	return 0;
}
DEFINE_SHOW_ATTRIBUTE(debugfs_usecount);

static int debugfs_trace_show(struct seq_file *f, void *offset)
{
	struct vchiq_instance *instance = f->private;
	int trace;

	trace = vchiq_instance_get_trace(instance);
	seq_printf(f, "%s\n", trace ? "Y" : "N");

	return 0;
}

static int vchiq_dump_show(struct seq_file *f, void *offset)
{
	vchiq_dump_state(f, &g_state);
	return 0;
}
DEFINE_SHOW_ATTRIBUTE(vchiq_dump);

static int debugfs_trace_open(struct inode *inode, struct file *file)
{
	return single_open(file, debugfs_trace_show, inode->i_private);
}

static ssize_t debugfs_trace_write(struct file *file,
	const char __user *buffer,
	size_t count, loff_t *ppos)
{
	struct seq_file *f = (struct seq_file *)file->private_data;
	struct vchiq_instance *instance = f->private;
	char firstchar;

	if (copy_from_user(&firstchar, buffer, 1))
		return -EFAULT;

	switch (firstchar) {
	case 'Y':
	case 'y':
	case '1':
		vchiq_instance_set_trace(instance, 1);
		break;
	case 'N':
	case 'n':
	case '0':
		vchiq_instance_set_trace(instance, 0);
		break;
	default:
		break;
	}

	*ppos += count;

	return count;
}

static const struct file_operations debugfs_trace_fops = {
	.owner		= THIS_MODULE,
	.open		= debugfs_trace_open,
	.write		= debugfs_trace_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

/* add an instance (process) to the debugfs entries */
void vchiq_debugfs_add_instance(struct vchiq_instance *instance)
{
	char pidstr[16];
	struct dentry *top;

	snprintf(pidstr, sizeof(pidstr), "%d",
		 vchiq_instance_get_pid(instance));

	top = debugfs_create_dir(pidstr, vchiq_dbg_clients);

	debugfs_create_file("use_count", 0444, top, instance,
			    &debugfs_usecount_fops);
	debugfs_create_file("trace", 0644, top, instance, &debugfs_trace_fops);

	vchiq_instance_get_debugfs_node(instance)->dentry = top;
}

void vchiq_debugfs_remove_instance(struct vchiq_instance *instance)
{
	struct vchiq_debugfs_node *node =
				vchiq_instance_get_debugfs_node(instance);

	debugfs_remove_recursive(node->dentry);
}

void vchiq_debugfs_init(void)
{
	vchiq_dbg_dir = debugfs_create_dir("vchiq", NULL);
	vchiq_dbg_clients = debugfs_create_dir("clients", vchiq_dbg_dir);

	debugfs_create_file("state", S_IFREG | 0444, vchiq_dbg_dir, NULL,
			    &vchiq_dump_fops);
}

/* remove all the debugfs entries */
void vchiq_debugfs_deinit(void)
{
	debugfs_remove_recursive(vchiq_dbg_dir);
}

#else /* CONFIG_DEBUG_FS */

void vchiq_debugfs_init(void)
{
}

void vchiq_debugfs_deinit(void)
{
}

void vchiq_debugfs_add_instance(struct vchiq_instance *instance)
{
}

void vchiq_debugfs_remove_instance(struct vchiq_instance *instance)
{
}

#endif /* CONFIG_DEBUG_FS */