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authorFernando Guzman Lugo <fernando.lugo@ti.com>2012-09-18 12:26:35 +0300
committerOhad Ben-Cohen <ohad@wizery.com>2012-09-18 12:53:41 +0300
commit2e37abb89a2ef13c524b0728bb9893f996a10b6b (patch)
tree11e760251317566b19cd9053608afa67cab88576 /drivers/remoteproc
parent70b85ef83ce3523f709b622d2c4cb31778686338 (diff)
downloadvexpress-lsk-2e37abb89a2ef13c524b0728bb9893f996a10b6b.tar.gz
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: Fernando Guzman Lugo <fernando.lugo@ti.com> [ohad: some white space, commentary and commit log changes] Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Diffstat (limited to 'drivers/remoteproc')
-rw-r--r--drivers/remoteproc/remoteproc_core.c3
-rw-r--r--drivers/remoteproc/remoteproc_debugfs.c81
2 files changed, 83 insertions, 1 deletions
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 5000d7589cf..29fc8236cac 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -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);
}
/**
diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index 03833850f21..10a38258e31 100644
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -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)