linux/drivers/remoteproc/remoteproc_debugfs.c
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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
  32/* remoteproc debugfs parent dir */
  33static 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 */
  44static 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
  53static 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 */
  63static 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 */
  72static 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
  88static 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 */
  95static 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
 108static const struct file_operations rproc_name_ops = {
 109        .read = rproc_name_read,
 110        .open = simple_open,
 111        .llseek = generic_file_llseek,
 112};
 113
 114void rproc_remove_trace_file(struct dentry *tfile)
 115{
 116        debugfs_remove(tfile);
 117}
 118
 119struct 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
 134void 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
 142void 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
 159void __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
 168void __exit rproc_exit_debugfs(void)
 169{
 170        if (rproc_dbg)
 171                debugfs_remove(rproc_dbg);
 172}
 173
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