Commit 2e37abb8 authored by Fernando Guzman Lugo's avatar Fernando Guzman Lugo Committed by Ohad Ben-Cohen

remoteproc: create a 'recovery' debugfs entry

Add a 'recovery' debugfs entry to dynamically disable/enable recovery
at runtime. This is useful when one is trying to debug an rproc crash;
without it, a recovery will immediately take place, making it harder
to debug the crash.

Contributions from Subramaniam Chanderashekarapuram.

Examples:

- disabling recovery:
$ echo disabled > <debugfs>/remoteproc/remoteproc0/recovery

- in case you want to recover a crash, but keep recovery disabled
  (useful in debugging sessions when you expect additional crashes
   you want to debug):
$ echo recover > <debugfs>/remoteproc/remoteproc0/recovery

- enabling recovery:
$ echo enabled > <debugfs>/remoteproc/remoteproc0/recovery
Signed-off-by: default avatarFernando Guzman Lugo <fernando.lugo@ti.com>
[ohad: some white space, commentary and commit log changes]
Signed-off-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
parent 70b85ef8
......@@ -965,7 +965,8 @@ static void rproc_crash_handler_work(struct work_struct *work)
mutex_unlock(&rproc->lock);
rproc_trigger_recovery(rproc);
if (!rproc->recovery_disabled)
rproc_trigger_recovery(rproc);
}
/**
......
......@@ -28,6 +28,9 @@
#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;
......@@ -111,6 +114,82 @@ static const struct file_operations rproc_name_ops = {
.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 ret;
/* 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);
......@@ -154,6 +233,8 @@ void rproc_create_debug_dir(struct rproc *rproc)
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)
......
......@@ -399,6 +399,7 @@ enum rproc_crash_type {
* @crash_handler: workqueue for handling a crash
* @crash_cnt: crash counter
* @crash_comp: completion used to sync crash handler and the rproc reload
* @recovery_disabled: flag that state if recovery was disabled
*/
struct rproc {
struct klist_node node;
......@@ -425,6 +426,7 @@ struct rproc {
struct work_struct crash_handler;
unsigned crash_cnt;
struct completion crash_comp;
bool recovery_disabled;
};
/* we currently support only two vrings per rvdev */
......
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