[PATCH v5 2/2] remoteproc: Move recovery configuration to sysfs

Rishabh Bhatnagar
2020-09-18T17:22:30Z

Move recovery configuration from debugfs to sysfs.This will
allow usage of this configuration feature in production
devices where access to debugfs might be limited.

Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
---
Documentation/ABI/testing/sysfs-class-remoteproc | 20 ++++++
drivers/remoteproc/remoteproc_debugfs.c | 78 ------------------------
drivers/remoteproc/remoteproc_sysfs.c | 56 +++++++++++++++++
3 files changed, 76 insertions(+), 78 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc b/Documentation/ABI/testing/sysfs-class-remoteproc
index f6c44fa..7368b50 100644
--- a/Documentation/ABI/testing/sysfs-class-remoteproc
+++ b/Documentation/ABI/testing/sysfs-class-remoteproc
@@ -82,3 +82,23 @@ Description: Remote processor coredump configuration
all data is read by usersapce.

"disabled" means no dump will be collected.
+
+What: /sys/class/remoteproc/.../recovery
+Date: July 2020
+Contact: Bjorn Andersson <bjorn.andersson@linaro.org>, Ohad Ben-Cohen <ohad@wizery.com>
+Description: Remote processor recovery mechanism
+
+ Reports the recovery mechanism of the remote processor,
+ which will be one of:
+
+ "enabled"
+ "disabled"
+
+ "enabled" means, 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" means, 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.
diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index 732770e..c505f0e 100644
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -84,82 +84,6 @@ 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 < 1 || count > sizeof(buf))
- return -EINVAL;
-
- 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)) {
- /* change the flag and begin the recovery process if needed */
- rproc->recovery_disabled = false;
- rproc_trigger_recovery(rproc);
- } else if (!strncmp(buf, "disabled", count)) {
- rproc->recovery_disabled = true;
- } else if (!strncmp(buf, "recover", count)) {
- /* begin the recovery process without changing the flag */
- rproc_trigger_recovery(rproc);
- } else {
- return -EINVAL;
- }
-
- 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,
-};
-
/* expose the crash trigger via debugfs */
static ssize_t
rproc_crash_write(struct file *filp, const char __user *user_buf,
@@ -329,8 +253,6 @@ void rproc_create_debug_dir(struct rproc *rproc)

debugfs_create_file("name", 0400, rproc->dbg_dir,
rproc, &rproc_name_ops);
- debugfs_create_file("recovery", 0600, rproc->dbg_dir,
- rproc, &rproc_recovery_ops);
debugfs_create_file("crash", 0200, rproc->dbg_dir,
rproc, &rproc_crash_ops);
debugfs_create_file("resource_table", 0400, rproc->dbg_dir,
diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index 40949a0..2508eca 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -10,6 +10,61 @@

#define to_rproc(d) container_of(d, struct rproc, dev)

+static ssize_t recovery_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rproc *rproc = to_rproc(dev);
+
+ return sprintf(buf, "%s", rproc->recovery_disabled ? "disabled\n" : "enabled\n");
+}
+
+/*
+ * By writing to the 'recovery' sysfs entry, we control the behavior of the
+ * recovery mechanism dynamically. The default value of this entry is "enabled".
+ *
+ * The 'recovery' sysfs 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 recovery_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rproc *rproc = to_rproc(dev);
+
+ if (sysfs_streq(buf, "enabled")) {
+ /* change the flag and begin the recovery process if needed */
+ rproc->recovery_disabled = false;
+ rproc_trigger_recovery(rproc);
+ } else if (sysfs_streq(buf, "disabled")) {
+ rproc->recovery_disabled = true;
+ } else if (sysfs_streq(buf, "recover")) {
+ /* begin the recovery process without changing the flag */
+ rproc_trigger_recovery(rproc);
+ } else {
+ return -EINVAL;
+ }
+
+ return count;
+}
+static DEVICE_ATTR_RW(recovery);
+
/*
* A coredump-configuration-to-string lookup table, for exposing a
* human readable configuration via sysfs. Always keep in sync with
@@ -202,6 +257,7 @@ static DEVICE_ATTR_RO(name);

static struct attribute *rproc_attrs[] = {
&dev_attr_coredump.attr,
+ &dev_attr_recovery.attr,
&dev_attr_firmware.attr,
&dev_attr_state.attr,
&dev_attr_name.attr,