drivers/remoteproc/remoteproc_debugfs.c

   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         debugfs_remove(rproc_dbg);
 252 }