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Ohad Ben-Cohen6391a702011-10-20 17:24:15 +02001/*
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>
Fernando Guzman Lugo2e37abb2012-09-18 12:26:35 +030031#include <linux/uaccess.h>
32
33#include "remoteproc_internal.h"
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +020034
35/* remoteproc debugfs parent dir */
36static struct dentry *rproc_dbg;
37
38/*
39 * Some remote processors may support dumping trace logs into a shared
40 * memory buffer. We expose this trace buffer using debugfs, so users
41 * can easily tell what's going on remotely.
42 *
43 * We will most probably improve the rproc tracing facilities later on,
44 * but this kind of lightweight and simple mechanism is always good to have,
45 * as it provides very early tracing with little to no dependencies at all.
46 */
47static ssize_t rproc_trace_read(struct file *filp, char __user *userbuf,
48 size_t count, loff_t *ppos)
49{
50 struct rproc_mem_entry *trace = filp->private_data;
51 int len = strnlen(trace->va, trace->len);
52
53 return simple_read_from_buffer(userbuf, count, ppos, trace->va, len);
54}
55
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +020056static const struct file_operations trace_rproc_ops = {
57 .read = rproc_trace_read,
Stephen Boyd234e3402012-04-05 14:25:11 -070058 .open = simple_open,
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +020059 .llseek = generic_file_llseek,
60};
61
62/*
63 * A state-to-string lookup table, for exposing a human readable state
64 * via debugfs. Always keep in sync with enum rproc_state
65 */
66static const char * const rproc_state_string[] = {
67 "offline",
68 "suspended",
69 "running",
70 "crashed",
71 "invalid",
72};
73
74/* expose the state of the remote processor via debugfs */
75static ssize_t rproc_state_read(struct file *filp, char __user *userbuf,
76 size_t count, loff_t *ppos)
77{
78 struct rproc *rproc = filp->private_data;
79 unsigned int state;
80 char buf[30];
81 int i;
82
83 state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
84
Dan Carpenterae768d52012-09-25 10:02:51 +030085 i = scnprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +020086 rproc->state);
87
88 return simple_read_from_buffer(userbuf, count, ppos, buf, i);
89}
90
91static const struct file_operations rproc_state_ops = {
92 .read = rproc_state_read,
Stephen Boyd234e3402012-04-05 14:25:11 -070093 .open = simple_open,
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +020094 .llseek = generic_file_llseek,
95};
96
97/* expose the name of the remote processor via debugfs */
98static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
99 size_t count, loff_t *ppos)
100{
101 struct rproc *rproc = filp->private_data;
102 /* need room for the name, a newline and a terminating null */
103 char buf[100];
104 int i;
105
Dan Carpenterae768d52012-09-25 10:02:51 +0300106 i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200107
108 return simple_read_from_buffer(userbuf, count, ppos, buf, i);
109}
110
111static const struct file_operations rproc_name_ops = {
112 .read = rproc_name_read,
Stephen Boyd234e3402012-04-05 14:25:11 -0700113 .open = simple_open,
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200114 .llseek = generic_file_llseek,
115};
116
Fernando Guzman Lugo2e37abb2012-09-18 12:26:35 +0300117/* expose recovery flag via debugfs */
118static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf,
119 size_t count, loff_t *ppos)
120{
121 struct rproc *rproc = filp->private_data;
122 char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n";
123
124 return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
125}
126
127/*
128 * By writing to the 'recovery' debugfs entry, we control the behavior of the
129 * recovery mechanism dynamically. The default value of this entry is "enabled".
130 *
131 * The 'recovery' debugfs entry supports these commands:
132 *
133 * enabled: When enabled, the remote processor will be automatically
134 * recovered whenever it crashes. Moreover, if the remote
135 * processor crashes while recovery is disabled, it will
136 * be automatically recovered too as soon as recovery is enabled.
137 *
138 * disabled: When disabled, a remote processor will remain in a crashed
139 * state if it crashes. This is useful for debugging purposes;
140 * without it, debugging a crash is substantially harder.
141 *
142 * recover: This function will trigger an immediate recovery if the
143 * remote processor is in a crashed state, without changing
144 * or checking the recovery state (enabled/disabled).
145 * This is useful during debugging sessions, when one expects
146 * additional crashes to happen after enabling recovery. In this
147 * case, enabling recovery will make it hard to debug subsequent
148 * crashes, so it's recommended to keep recovery disabled, and
149 * instead use the "recover" command as needed.
150 */
151static ssize_t
152rproc_recovery_write(struct file *filp, const char __user *user_buf,
153 size_t count, loff_t *ppos)
154{
155 struct rproc *rproc = filp->private_data;
156 char buf[10];
157 int ret;
158
159 if (count > sizeof(buf))
160 return count;
161
162 ret = copy_from_user(buf, user_buf, count);
163 if (ret)
Dan Carpenterbec109a2012-09-25 10:05:33 +0300164 return -EFAULT;
Fernando Guzman Lugo2e37abb2012-09-18 12:26:35 +0300165
166 /* remove end of line */
167 if (buf[count - 1] == '\n')
168 buf[count - 1] = '\0';
169
170 if (!strncmp(buf, "enabled", count)) {
171 rproc->recovery_disabled = false;
172 /* if rproc has crashed, trigger recovery */
173 if (rproc->state == RPROC_CRASHED)
174 rproc_trigger_recovery(rproc);
175 } else if (!strncmp(buf, "disabled", count)) {
176 rproc->recovery_disabled = true;
177 } else if (!strncmp(buf, "recover", count)) {
178 /* if rproc has crashed, trigger recovery */
179 if (rproc->state == RPROC_CRASHED)
180 rproc_trigger_recovery(rproc);
181 }
182
183 return count;
184}
185
186static const struct file_operations rproc_recovery_ops = {
187 .read = rproc_recovery_read,
188 .write = rproc_recovery_write,
189 .open = simple_open,
190 .llseek = generic_file_llseek,
191};
192
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200193void rproc_remove_trace_file(struct dentry *tfile)
194{
195 debugfs_remove(tfile);
196}
197
198struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
199 struct rproc_mem_entry *trace)
200{
201 struct dentry *tfile;
202
203 tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
204 trace, &trace_rproc_ops);
205 if (!tfile) {
Ohad Ben-Cohenb5ab5e22012-05-30 22:01:25 +0300206 dev_err(&rproc->dev, "failed to create debugfs trace entry\n");
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200207 return NULL;
208 }
209
210 return tfile;
211}
212
213void rproc_delete_debug_dir(struct rproc *rproc)
214{
215 if (!rproc->dbg_dir)
216 return;
217
218 debugfs_remove_recursive(rproc->dbg_dir);
219}
220
221void rproc_create_debug_dir(struct rproc *rproc)
222{
Ohad Ben-Cohenb5ab5e22012-05-30 22:01:25 +0300223 struct device *dev = &rproc->dev;
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200224
225 if (!rproc_dbg)
226 return;
227
228 rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
229 if (!rproc->dbg_dir)
230 return;
231
232 debugfs_create_file("name", 0400, rproc->dbg_dir,
233 rproc, &rproc_name_ops);
234 debugfs_create_file("state", 0400, rproc->dbg_dir,
235 rproc, &rproc_state_ops);
Fernando Guzman Lugo2e37abb2012-09-18 12:26:35 +0300236 debugfs_create_file("recovery", 0400, rproc->dbg_dir,
237 rproc, &rproc_recovery_ops);
Ohad Ben-Cohen6391a702011-10-20 17:24:15 +0200238}
239
240void __init rproc_init_debugfs(void)
241{
242 if (debugfs_initialized()) {
243 rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
244 if (!rproc_dbg)
245 pr_err("can't create debugfs dir\n");
246 }
247}
248
249void __exit rproc_exit_debugfs(void)
250{
251 if (rproc_dbg)
252 debugfs_remove(rproc_dbg);
253}