1 /*
2  * Remote Processor Framework
3  *
4  * Copyright (C) 2011 Texas Instruments, Inc.
5  * Copyright (C) 2011 Google, Inc.
6  *
7  * Ohad Ben-Cohen <ohad@wizery.com>
8  * Mark Grosen <mgrosen@ti.com>
9  * Brian Swetland <swetland@google.com>
10  * Fernando Guzman Lugo <fernando.lugo@ti.com>
11  * Suman Anna <s-anna@ti.com>
12  * Robert Tivy <rtivy@ti.com>
13  * Armando Uribe De Leon <x0095078@ti.com>
14  *
15  * This program is free software; you can redistribute it and/or
16  * modify it under the terms of the GNU General Public License
17  * version 2 as published by the Free Software Foundation.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  */
24 
25 #define pr_fmt(fmt)    "%s: " fmt, __func__
26 
27 #include <linux/kernel.h>
28 #include <linux/debugfs.h>
29 #include <linux/remoteproc.h>
30 #include <linux/device.h>
31 
32 /* remoteproc debugfs parent dir */
33 static struct dentry *rproc_dbg;
34 
35 /*
36  * Some remote processors may support dumping trace logs into a shared
37  * memory buffer. We expose this trace buffer using debugfs, so users
38  * can easily tell what's going on remotely.
39  *
40  * We will most probably improve the rproc tracing facilities later on,
41  * but this kind of lightweight and simple mechanism is always good to have,
42  * as it provides very early tracing with little to no dependencies at all.
43  */
44 static ssize_t rproc_trace_read(struct file *filp, char __user *userbuf,
45 						size_t count, loff_t *ppos)
46 {
47 	struct rproc_mem_entry *trace = filp->private_data;
48 	int len = strnlen(trace->va, trace->len);
49 
50 	return simple_read_from_buffer(userbuf, count, ppos, trace->va, len);
51 }
52 
53 static const struct file_operations trace_rproc_ops = {
54 	.read = rproc_trace_read,
55 	.open = simple_open,
56 	.llseek	= generic_file_llseek,
57 };
58 
59 /*
60  * A state-to-string lookup table, for exposing a human readable state
61  * via debugfs. Always keep in sync with enum rproc_state
62  */
63 static const char * const rproc_state_string[] = {
64 	"offline",
65 	"suspended",
66 	"running",
67 	"crashed",
68 	"invalid",
69 };
70 
71 /* expose the state of the remote processor via debugfs */
72 static ssize_t rproc_state_read(struct file *filp, char __user *userbuf,
73 						size_t count, loff_t *ppos)
74 {
75 	struct rproc *rproc = filp->private_data;
76 	unsigned int state;
77 	char buf[30];
78 	int i;
79 
80 	state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
81 
82 	i = snprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
83 							rproc->state);
84 
85 	return simple_read_from_buffer(userbuf, count, ppos, buf, i);
86 }
87 
88 static const struct file_operations rproc_state_ops = {
89 	.read = rproc_state_read,
90 	.open = simple_open,
91 	.llseek	= generic_file_llseek,
92 };
93 
94 /* expose the name of the remote processor via debugfs */
95 static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
96 						size_t count, loff_t *ppos)
97 {
98 	struct rproc *rproc = filp->private_data;
99 	/* need room for the name, a newline and a terminating null */
100 	char buf[100];
101 	int i;
102 
103 	i = snprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
104 
105 	return simple_read_from_buffer(userbuf, count, ppos, buf, i);
106 }
107 
108 static const struct file_operations rproc_name_ops = {
109 	.read = rproc_name_read,
110 	.open = simple_open,
111 	.llseek	= generic_file_llseek,
112 };
113 
114 void rproc_remove_trace_file(struct dentry *tfile)
115 {
116 	debugfs_remove(tfile);
117 }
118 
119 struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
120 					struct rproc_mem_entry *trace)
121 {
122 	struct dentry *tfile;
123 
124 	tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
125 						trace, &trace_rproc_ops);
126 	if (!tfile) {
127 		dev_err(rproc->dev, "failed to create debugfs trace entry\n");
128 		return NULL;
129 	}
130 
131 	return tfile;
132 }
133 
134 void rproc_delete_debug_dir(struct rproc *rproc)
135 {
136 	if (!rproc->dbg_dir)
137 		return;
138 
139 	debugfs_remove_recursive(rproc->dbg_dir);
140 }
141 
142 void rproc_create_debug_dir(struct rproc *rproc)
143 {
144 	struct device *dev = rproc->dev;
145 
146 	if (!rproc_dbg)
147 		return;
148 
149 	rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
150 	if (!rproc->dbg_dir)
151 		return;
152 
153 	debugfs_create_file("name", 0400, rproc->dbg_dir,
154 					rproc, &rproc_name_ops);
155 	debugfs_create_file("state", 0400, rproc->dbg_dir,
156 					rproc, &rproc_state_ops);
157 }
158 
159 void __init rproc_init_debugfs(void)
160 {
161 	if (debugfs_initialized()) {
162 		rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
163 		if (!rproc_dbg)
164 			pr_err("can't create debugfs dir\n");
165 	}
166 }
167 
168 void __exit rproc_exit_debugfs(void)
169 {
170 	if (rproc_dbg)
171 		debugfs_remove(rproc_dbg);
172 }
173