debugfs-client.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
  4 */
  5#include <linux/debugfs.h>
  6#include <linux/interconnect.h>
  7#include <linux/platform_device.h>
  8
  9#include "internal.h"
 10
 11/*
 12 * This can be dangerous, therefore don't provide any real compile time
 13 * configuration option for this feature.
 14 * People who want to use this will need to modify the source code directly.
 15 */
 16#undef INTERCONNECT_ALLOW_WRITE_DEBUGFS
 17
 18#if defined(INTERCONNECT_ALLOW_WRITE_DEBUGFS) && defined(CONFIG_DEBUG_FS)
 19
 20static LIST_HEAD(debugfs_paths);
 21static DEFINE_MUTEX(debugfs_lock);
 22
 23static struct platform_device *pdev;
 24static struct icc_path *cur_path;
 25
 26static char *src_node;
 27static char *dst_node;
 28static u32 avg_bw;
 29static u32 peak_bw;
 30static u32 tag;
 31
 32struct debugfs_path {
 33	const char *src;
 34	const char *dst;
 35	struct icc_path *path;
 36	struct list_head list;
 37};
 38
 39static struct icc_path *get_path(const char *src, const char *dst)
 40{
 41	struct debugfs_path *path;
 42
 43	list_for_each_entry(path, &debugfs_paths, list) {
 44		if (!strcmp(path->src, src) && !strcmp(path->dst, dst))
 45			return path->path;
 46	}
 47
 48	return NULL;
 49}
 50
 51static int icc_get_set(void *data, u64 val)
 52{
 53	struct debugfs_path *debugfs_path;
 54	char *src, *dst;
 55	int ret = 0;
 56
 57	mutex_lock(&debugfs_lock);
 58
 59	rcu_read_lock();
 60	src = rcu_dereference(src_node);
 61	dst = rcu_dereference(dst_node);
 62
 63	/*
 64	 * If we've already looked up a path, then use the existing one instead
 65	 * of calling icc_get() again. This allows for updating previous BW
 66	 * votes when "get" is written to multiple times for multiple paths.
 67	 */
 68	cur_path = get_path(src, dst);
 69	if (cur_path) {
 70		rcu_read_unlock();
 71		goto out;
 72	}
 73
 74	src = kstrdup(src, GFP_ATOMIC);
 75	dst = kstrdup(dst, GFP_ATOMIC);
 76	rcu_read_unlock();
 77
 78	if (!src || !dst) {
 79		ret = -ENOMEM;
 80		goto err_free;
 81	}
 82
 83	cur_path = icc_get(&pdev->dev, src, dst);
 84	if (IS_ERR(cur_path)) {
 85		ret = PTR_ERR(cur_path);
 86		goto err_free;
 87	}
 88
 89	debugfs_path = kzalloc(sizeof(*debugfs_path), GFP_KERNEL);
 90	if (!debugfs_path) {
 91		ret = -ENOMEM;
 92		goto err_put;
 93	}
 94
 95	debugfs_path->path = cur_path;
 96	debugfs_path->src = src;
 97	debugfs_path->dst = dst;
 98	list_add_tail(&debugfs_path->list, &debugfs_paths);
 99
100	goto out;
101
102err_put:
103	icc_put(cur_path);
104err_free:
105	kfree(src);
106	kfree(dst);
107out:
108	mutex_unlock(&debugfs_lock);
109	return ret;
110}
111
112DEFINE_DEBUGFS_ATTRIBUTE(icc_get_fops, NULL, icc_get_set, "%llu\n");
113
114static int icc_commit_set(void *data, u64 val)
115{
116	int ret;
117
118	mutex_lock(&debugfs_lock);
119
120	if (!cur_path) {
121		ret = -EINVAL;
122		goto out;
123	}
124
125	if (IS_ERR(cur_path)) {
126		ret = PTR_ERR(cur_path);
127		goto out;
128	}
129
130	icc_set_tag(cur_path, tag);
131	ret = icc_set_bw(cur_path, avg_bw, peak_bw);
132out:
133	mutex_unlock(&debugfs_lock);
134	return ret;
135}
136
137DEFINE_DEBUGFS_ATTRIBUTE(icc_commit_fops, NULL, icc_commit_set, "%llu\n");
138
139int icc_debugfs_client_init(struct dentry *icc_dir)
140{
141	struct dentry *client_dir;
142	int ret;
143
144	pdev = platform_device_alloc("icc-debugfs-client", PLATFORM_DEVID_NONE);
145
146	ret = platform_device_add(pdev);
147	if (ret) {
148		pr_err("%s: failed to add platform device: %d\n", __func__, ret);
149		platform_device_put(pdev);
150		return ret;
151	}
152
153	src_node = devm_kstrdup(&pdev->dev, "", GFP_KERNEL);
154	dst_node = devm_kstrdup(&pdev->dev, "", GFP_KERNEL);
155	if (!src_node || !dst_node)
156		return -ENOMEM;
157
158	client_dir = debugfs_create_dir("test_client", icc_dir);
159
160	debugfs_create_str("src_node", 0600, client_dir, &src_node);
161	debugfs_create_str("dst_node", 0600, client_dir, &dst_node);
162	debugfs_create_file("get", 0200, client_dir, NULL, &icc_get_fops);
163	debugfs_create_u32("avg_bw", 0600, client_dir, &avg_bw);
164	debugfs_create_u32("peak_bw", 0600, client_dir, &peak_bw);
165	debugfs_create_u32("tag", 0600, client_dir, &tag);
166	debugfs_create_file("commit", 0200, client_dir, NULL, &icc_commit_fops);
167
168	return 0;
169}
170
171#else
172
173int icc_debugfs_client_init(struct dentry *icc_dir)
174{
175	return 0;
176}
177
178#endif