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Date:   Thu, 17 Sep 2020 11:56:39 -0700
From:   Rishabh Bhatnagar <rishabhb@...eaurora.org>
To:     bjorn.andersson@...aro.org, ohad@...ery.com
Cc:     linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        tsoni@...eaurora.org, psodagud@...eaurora.org,
        sidgup@...eaurora.org, Rishabh Bhatnagar <rishabhb@...eaurora.org>
Subject: [PATCH v4 2/2] remoteproc: Move recovery configuration to sysfs

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@...eaurora.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@...aro.org>, Ohad Ben-Cohen <ohad@...ery.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,
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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