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
  32 /* remoteproc debugfs parent dir */
  33 static struct dentry *rproc_dbg;
  34
  35 /*
  36  * Some remote processors may support dumping trace logs into a shared
  37  * memory buffer. We expose this trace buffer using debugfs, so users
  38  * can easily tell what's going on remotely.
  39  *
  40  * We will most probably improve the rproc tracing facilities later on,
  41  * but this kind of lightweight and simple mechanism is always good to have,
  42  * as it provides very early tracing with little to no dependencies at all.
  43  */
  44 static ssize_t rproc_trace_read(struct file *filp, char __user *userbuf,
  45                                                 size_t count, loff_t *ppos)
  46 {
  47         struct rproc_mem_entry *trace = filp->private_data;
  48         int len = strnlen(trace->va, trace->len);
  49
  50         return simple_read_from_buffer(userbuf, count, ppos, trace->va, len);
  51 }
  52
  53 static const struct file_operations trace_rproc_ops = {
  54         .read = rproc_trace_read,
  55         .open = simple_open,
  56         .llseek = generic_file_llseek,
  57 };
  58
  59 /*
  60  * A state-to-string lookup table, for exposing a human readable state
  61  * via debugfs. Always keep in sync with enum rproc_state
  62  */
  63 static const char * const rproc_state_string[] = {
  64         "offline",
  65         "suspended",
  66         "running",
  67         "crashed",
  68         "invalid",
  69 };
  70
  71 /* expose the state of the remote processor via debugfs */
  72 static ssize_t rproc_state_read(struct file *filp, char __user *userbuf,
  73                                                 size_t count, loff_t *ppos)
  74 {
  75         struct rproc *rproc = filp->private_data;
  76         unsigned int state;
  77         char buf[30];
  78         int i;
  79
  80         state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
  81
  82         i = snprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
  83                                                         rproc->state);
  84
  85         return simple_read_from_buffer(userbuf, count, ppos, buf, i);
  86 }
  87
  88 static const struct file_operations rproc_state_ops = {
  89         .read = rproc_state_read,
  90         .open = simple_open,
  91         .llseek = generic_file_llseek,
  92 };
  93
  94 /* expose the name of the remote processor via debugfs */
  95 static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
  96                                                 size_t count, loff_t *ppos)
  97 {
  98         struct rproc *rproc = filp->private_data;
  99         /* need room for the name, a newline and a terminating null */
 100         char buf[100];
 101         int i;
 102
 103         i = snprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
 104
 105         return simple_read_from_buffer(userbuf, count, ppos, buf, i);
 106 }
 107
 108 static const struct file_operations rproc_name_ops = {
 109         .read = rproc_name_read,
 110         .open = simple_open,
 111         .llseek = generic_file_llseek,
 112 };
 113
 114 void rproc_remove_trace_file(struct dentry *tfile)
 115 {
 116         debugfs_remove(tfile);
 117 }
 118
 119 struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
 120                                         struct rproc_mem_entry *trace)
 121 {
 122         struct dentry *tfile;
 123
 124         tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
 125                                                 trace, &trace_rproc_ops);
 126         if (!tfile) {
 127                 dev_err(rproc->dev, "failed to create debugfs trace entry\n");
 128                 return NULL;
 129         }
 130
 131         return tfile;
 132 }
 133
 134 void rproc_delete_debug_dir(struct rproc *rproc)
 135 {
 136         if (!rproc->dbg_dir)
 137                 return;
 138
 139         debugfs_remove_recursive(rproc->dbg_dir);
 140 }
 141
 142 void rproc_create_debug_dir(struct rproc *rproc)
 143 {
 144         struct device *dev = rproc->dev;
 145
 146         if (!rproc_dbg)
 147                 return;
 148
 149         rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
 150         if (!rproc->dbg_dir)
 151                 return;
 152
 153         debugfs_create_file("name", 0400, rproc->dbg_dir,
 154                                         rproc, &rproc_name_ops);
 155         debugfs_create_file("state", 0400, rproc->dbg_dir,
 156                                         rproc, &rproc_state_ops);
 157 }
 158
 159 void __init rproc_init_debugfs(void)
 160 {
 161         if (debugfs_initialized()) {
 162                 rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
 163                 if (!rproc_dbg)
 164                         pr_err("can't create debugfs dir\n");
 165         }
 166 }
 167
 168 void __exit rproc_exit_debugfs(void)
 169 {
 170         if (rproc_dbg)
 171                 debugfs_remove(rproc_dbg);
 172 }