/*
* Remote Processor Framework
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
*
* Ohad Ben-Cohen <ohad@wizery.com>
* Mark Grosen <mgrosen@ti.com>
* Brian Swetland <swetland@google.com>
* Fernando Guzman Lugo <fernando.lugo@ti.com>
* Suman Anna <s-anna@ti.com>
* Robert Tivy <rtivy@ti.com>
* Armando Uribe De Leon <x0095078@ti.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/kernel.h>
#include <linux/debugfs.h>
#include <linux/remoteproc.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include "remoteproc_internal.h"
/* remoteproc debugfs parent dir */
static struct dentry *rproc_dbg;
/*
* Some remote processors may support dumping trace logs into a shared
* memory buffer. We expose this trace buffer using debugfs, so users
* can easily tell what's going on remotely.
*
* We will most probably improve the rproc tracing facilities later on,
* but this kind of lightweight and simple mechanism is always good to have,
* as it provides very early tracing with little to no dependencies at all.
*/
static ssize_t rproc_trace_read(struct file *filp, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rproc_mem_entry *trace = filp->private_data;
int len = strnlen(trace->va, trace->len);
return simple_read_from_buffer(userbuf, count, ppos, trace->va, len);
}
static const struct file_operations trace_rproc_ops = {
.read = rproc_trace_read,
.open = simple_open,
.llseek = generic_file_llseek,
};
/*
* A state-to-string lookup table, for exposing a human readable state
* via debugfs. Always keep in sync with enum rproc_state
*/
static const char * const rproc_state_string[] = {
"offline",
"suspended",
"running",
"crashed",
"invalid",
};
/* expose the state of the remote processor via debugfs */
static ssize_t rproc_state_read(struct file *filp, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rproc *rproc = filp->private_data;
unsigned int state;
char buf[30];
int i;
state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
i = scnprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
rproc->state);
return simple_read_from_buffer(userbuf, count, ppos, buf, i);
}
static const struct file_operations rproc_state_ops = {
.read = rproc_state_read,
.open = simple_open,
.llseek = generic_file_llseek,
};
/* expose the name of the remote processor via debugfs */
static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rproc *rproc = filp->private_data;
/* need room for the name, a newline and a terminating null */
char buf[100];
int i;
i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
return simple_read_from_buffer(userbuf, count, ppos, buf, i);
}
static const struct file_operations rproc_name_ops = {
.read = rproc_name_read,
.open = simple_open,
.llseek = generic_file_llseek,
};
/* expose recovery flag via debugfs */
static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rproc *rproc = filp->private_data;
char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n";
return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
}
/*
* By writing to the 'recovery' debugfs entry, we control the behavior of the
* recovery mechanism dynamically. The default value of this entry is "enabled".
*
* The 'recovery' debugfs entry supports these commands:
*
* enabled: When enabled, the remote processor will be automatically
* recovered whenever it crashes. Moreover, if the remote
* processor crashes while recovery is disabled, it will
* be automatically recovered too as soon as recovery is enabled.
*
* disabled: When disabled, a remote processor will remain in a crashed
* state if it crashes. This is useful for debugging purposes;
* without it, debugging a crash is substantially harder.
*
* recover: This function will trigger an immediate recovery if the
* remote processor is in a crashed state, without changing
* or checking the recovery state (enabled/disabled).
* This is useful during debugging sessions, when one expects
* additional crashes to happen after enabling recovery. In this
* case, enabling recovery will make it hard to debug subsequent
* crashes, so it's recommended to keep recovery disabled, and
* instead use the "recover" command as needed.
*/
static ssize_t
rproc_recovery_write(struct file *filp, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct rproc *rproc = filp->private_data;
char buf[10];
int ret;
if (count > sizeof(buf))
return count;
ret = copy_from_user(buf, user_buf, count);
if (ret)
return -EFAULT;
/* remove end of line */
if (buf[count - 1] == '\n')
buf[count - 1] = '\0';
if (!strncmp(buf, "enabled", count)) {
rproc->recovery_disabled = false;
/* if rproc has crashed, trigger recovery */
if (rproc->state == RPROC_CRASHED)
rproc_trigger_recovery(rproc);
} else if (!strncmp(buf, "disabled", count)) {
rproc->recovery_disabled = true;
} else if (!strncmp(buf, "recover", count)) {
/* if rproc has crashed, trigger recovery */
if (rproc->state == RPROC_CRASHED)
rproc_trigger_recovery(rproc);
}
return count;
}
static const struct file_operations rproc_recovery_ops = {
.read = rproc_recovery_read,
.write = rproc_recovery_write,
.open = simple_open,
.llseek = generic_file_llseek,
};
void rproc_remove_trace_file(struct dentry *tfile)
{
debugfs_remove(tfile);
}
struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
struct rproc_mem_entry *trace)
{
struct dentry *tfile;
tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
trace, &trace_rproc_ops);
if (!tfile) {
dev_err(&rproc->dev, "failed to create debugfs trace entry\n");
return NULL;
}
return tfile;
}
void rproc_delete_debug_dir(struct rproc *rproc)
{
if (!rproc->dbg_dir)
return;
debugfs_remove_recursive(rproc->dbg_dir);
}
void rproc_create_debug_dir(struct rproc *rproc)
{
struct device *dev = &rproc->dev;
if (!rproc_dbg)
return;
rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
if (!rproc->dbg_dir)
return;
debugfs_create_file("name", 0400, rproc->dbg_dir,
rproc, &rproc_name_ops);
debugfs_create_file("state", 0400, rproc->dbg_dir,
rproc, &rproc_state_ops);
debugfs_create_file("recovery", 0400, rproc->dbg_dir,
rproc, &rproc_recovery_ops);
}
void __init rproc_init_debugfs(void)
{
if (debugfs_initialized()) {
rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
if (!rproc_dbg)
pr_err("can't create debugfs dir\n");
}
}
void __exit rproc_exit_debugfs(void)
{
debugfs_remove(rproc_dbg);
}
