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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 | #include <linux/uaccess.h> |
32 | |
33 | #include "remoteproc_internal.h" |
34 | |
35 | /* remoteproc debugfs parent dir */ |
36 | static 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 | */ |
47 | static 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 | |
56 | static const struct file_operations trace_rproc_ops = { |
57 | .read = rproc_trace_read, |
58 | .open = simple_open, |
59 | .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 | */ |
66 | static 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 */ |
75 | static 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 | |
85 | i = scnprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state], |
86 | rproc->state); |
87 | |
88 | return simple_read_from_buffer(userbuf, count, ppos, buf, i); |
89 | } |
90 | |
91 | static const struct file_operations rproc_state_ops = { |
92 | .read = rproc_state_read, |
93 | .open = simple_open, |
94 | .llseek = generic_file_llseek, |
95 | }; |
96 | |
97 | /* expose the name of the remote processor via debugfs */ |
98 | static 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 | |
106 | i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name); |
107 | |
108 | return simple_read_from_buffer(userbuf, count, ppos, buf, i); |
109 | } |
110 | |
111 | static const struct file_operations rproc_name_ops = { |
112 | .read = rproc_name_read, |
113 | .open = simple_open, |
114 | .llseek = generic_file_llseek, |
115 | }; |
116 | |
117 | /* expose recovery flag via debugfs */ |
118 | static 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 | */ |
151 | static ssize_t |
152 | rproc_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) |
164 | return -EFAULT; |
165 | |
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 | |
186 | static 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 | |
193 | void rproc_remove_trace_file(struct dentry *tfile) |
194 | { |
195 | debugfs_remove(tfile); |
196 | } |
197 | |
198 | struct 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) { |
206 | dev_err(&rproc->dev, "failed to create debugfs trace entry\n"); |
207 | return NULL; |
208 | } |
209 | |
210 | return tfile; |
211 | } |
212 | |
213 | void 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 | |
221 | void rproc_create_debug_dir(struct rproc *rproc) |
222 | { |
223 | struct device *dev = &rproc->dev; |
224 | |
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); |
236 | debugfs_create_file("recovery", 0400, rproc->dbg_dir, |
237 | rproc, &rproc_recovery_ops); |
238 | } |
239 | |
240 | void __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 | |
249 | void __exit rproc_exit_debugfs(void) |
250 | { |
251 | if (rproc_dbg) |
252 | debugfs_remove(rproc_dbg); |
253 | } |
254 |
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