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 < 1 || 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 debugfs_remove(rproc_dbg); 252 } 253