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 
20 static LIST_HEAD(debugfs_paths);
21 static DEFINE_MUTEX(debugfs_lock);
22 
23 static struct platform_device *pdev;
24 static struct icc_path *cur_path;
25 
26 static char *src_node;
27 static char *dst_node;
28 static u32 avg_bw;
29 static u32 peak_bw;
30 static u32 tag;
31 
32 struct debugfs_path {
33 	const char *src;
34 	const char *dst;
35 	struct icc_path *path;
36 	struct list_head list;
37 };
38 
39 static 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 
51 static 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 
102 err_put:
103 	icc_put(cur_path);
104 err_free:
105 	kfree(src);
106 	kfree(dst);
107 out:
108 	mutex_unlock(&debugfs_lock);
109 	return ret;
110 }
111 
112 DEFINE_DEBUGFS_ATTRIBUTE(icc_get_fops, NULL, icc_get_set, "%llu\n");
113 
114 static int icc_commit_set(void *data, u64 val)
115 {
116 	int ret;
117 
118 	mutex_lock(&debugfs_lock);
119 
120 	if (IS_ERR_OR_NULL(cur_path)) {
121 		ret = PTR_ERR(cur_path);
122 		goto out;
123 	}
124 
125 	icc_set_tag(cur_path, tag);
126 	ret = icc_set_bw(cur_path, avg_bw, peak_bw);
127 out:
128 	mutex_unlock(&debugfs_lock);
129 	return ret;
130 }
131 
132 DEFINE_DEBUGFS_ATTRIBUTE(icc_commit_fops, NULL, icc_commit_set, "%llu\n");
133 
134 int icc_debugfs_client_init(struct dentry *icc_dir)
135 {
136 	struct dentry *client_dir;
137 	int ret;
138 
139 	pdev = platform_device_alloc("icc-debugfs-client", PLATFORM_DEVID_NONE);
140 
141 	ret = platform_device_add(pdev);
142 	if (ret) {
143 		pr_err("%s: failed to add platform device: %d\n", __func__, ret);
144 		platform_device_put(pdev);
145 		return ret;
146 	}
147 
148 	client_dir = debugfs_create_dir("test_client", icc_dir);
149 
150 	debugfs_create_str("src_node", 0600, client_dir, &src_node);
151 	debugfs_create_str("dst_node", 0600, client_dir, &dst_node);
152 	debugfs_create_file("get", 0200, client_dir, NULL, &icc_get_fops);
153 	debugfs_create_u32("avg_bw", 0600, client_dir, &avg_bw);
154 	debugfs_create_u32("peak_bw", 0600, client_dir, &peak_bw);
155 	debugfs_create_u32("tag", 0600, client_dir, &tag);
156 	debugfs_create_file("commit", 0200, client_dir, NULL, &icc_commit_fops);
157 
158 	return 0;
159 }
160 
161 #else
162 
163 int icc_debugfs_client_init(struct dentry *icc_dir)
164 {
165 	return 0;
166 }
167 
168 #endif
169