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 /* expose the name of the remote processor via debugfs */ 63 static ssize_t rproc_name_read(struct file *filp, char __user *userbuf, 64 size_t count, loff_t *ppos) 65 { 66 struct rproc *rproc = filp->private_data; 67 /* need room for the name, a newline and a terminating null */ 68 char buf[100]; 69 int i; 70 71 i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name); 72 73 return simple_read_from_buffer(userbuf, count, ppos, buf, i); 74 } 75 76 static const struct file_operations rproc_name_ops = { 77 .read = rproc_name_read, 78 .open = simple_open, 79 .llseek = generic_file_llseek, 80 }; 81 82 /* expose recovery flag via debugfs */ 83 static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf, 84 size_t count, loff_t *ppos) 85 { 86 struct rproc *rproc = filp->private_data; 87 char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n"; 88 89 return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf)); 90 } 91 92 /* 93 * By writing to the 'recovery' debugfs entry, we control the behavior of the 94 * recovery mechanism dynamically. The default value of this entry is "enabled". 95 * 96 * The 'recovery' debugfs entry supports these commands: 97 * 98 * enabled: When enabled, the remote processor will be automatically 99 * recovered whenever it crashes. Moreover, if the remote 100 * processor crashes while recovery is disabled, it will 101 * be automatically recovered too as soon as recovery is enabled. 102 * 103 * disabled: When disabled, a remote processor will remain in a crashed 104 * state if it crashes. This is useful for debugging purposes; 105 * without it, debugging a crash is substantially harder. 106 * 107 * recover: This function will trigger an immediate recovery if the 108 * remote processor is in a crashed state, without changing 109 * or checking the recovery state (enabled/disabled). 110 * This is useful during debugging sessions, when one expects 111 * additional crashes to happen after enabling recovery. In this 112 * case, enabling recovery will make it hard to debug subsequent 113 * crashes, so it's recommended to keep recovery disabled, and 114 * instead use the "recover" command as needed. 115 */ 116 static ssize_t 117 rproc_recovery_write(struct file *filp, const char __user *user_buf, 118 size_t count, loff_t *ppos) 119 { 120 struct rproc *rproc = filp->private_data; 121 char buf[10]; 122 int ret; 123 124 if (count < 1 || count > sizeof(buf)) 125 return -EINVAL; 126 127 ret = copy_from_user(buf, user_buf, count); 128 if (ret) 129 return -EFAULT; 130 131 /* remove end of line */ 132 if (buf[count - 1] == '\n') 133 buf[count - 1] = '\0'; 134 135 if (!strncmp(buf, "enabled", count)) { 136 rproc->recovery_disabled = false; 137 /* if rproc has crashed, trigger recovery */ 138 if (rproc->state == RPROC_CRASHED) 139 rproc_trigger_recovery(rproc); 140 } else if (!strncmp(buf, "disabled", count)) { 141 rproc->recovery_disabled = true; 142 } else if (!strncmp(buf, "recover", count)) { 143 /* if rproc has crashed, trigger recovery */ 144 if (rproc->state == RPROC_CRASHED) 145 rproc_trigger_recovery(rproc); 146 } 147 148 return count; 149 } 150 151 static const struct file_operations rproc_recovery_ops = { 152 .read = rproc_recovery_read, 153 .write = rproc_recovery_write, 154 .open = simple_open, 155 .llseek = generic_file_llseek, 156 }; 157 158 void rproc_remove_trace_file(struct dentry *tfile) 159 { 160 debugfs_remove(tfile); 161 } 162 163 struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc, 164 struct rproc_mem_entry *trace) 165 { 166 struct dentry *tfile; 167 168 tfile = debugfs_create_file(name, 0400, rproc->dbg_dir, trace, 169 &trace_rproc_ops); 170 if (!tfile) { 171 dev_err(&rproc->dev, "failed to create debugfs trace entry\n"); 172 return NULL; 173 } 174 175 return tfile; 176 } 177 178 void rproc_delete_debug_dir(struct rproc *rproc) 179 { 180 if (!rproc->dbg_dir) 181 return; 182 183 debugfs_remove_recursive(rproc->dbg_dir); 184 } 185 186 void rproc_create_debug_dir(struct rproc *rproc) 187 { 188 struct device *dev = &rproc->dev; 189 190 if (!rproc_dbg) 191 return; 192 193 rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg); 194 if (!rproc->dbg_dir) 195 return; 196 197 debugfs_create_file("name", 0400, rproc->dbg_dir, 198 rproc, &rproc_name_ops); 199 debugfs_create_file("recovery", 0400, rproc->dbg_dir, 200 rproc, &rproc_recovery_ops); 201 } 202 203 void __init rproc_init_debugfs(void) 204 { 205 if (debugfs_initialized()) { 206 rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL); 207 if (!rproc_dbg) 208 pr_err("can't create debugfs dir\n"); 209 } 210 } 211 212 void __exit rproc_exit_debugfs(void) 213 { 214 debugfs_remove(rproc_dbg); 215 } 216