[PATCH v12 1/8] power: reset: reboot-mode: Add device tree node-based registration

[Shivendra Pratap]

The reboot-mode driver does not have a strict requirement for
device-based registration. It primarily uses the device's of_node
to read mode-<cmd> properties and the device pointer for logging.

Remove the dependency on struct device and introduce support for
Device Tree (DT) node-based registration. This enables drivers
that are not associated with a struct device to leverage the
reboot-mode framework.

Signed-off-by: Shivendra Pratap <shivendra.pratap at oss.qualcomm.com>
---
 drivers/power/reset/reboot-mode.c | 45 +++++++++++++++++++++++++++++----------
 include/linux/reboot-mode.h       |  6 +++++-
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index fba53f638da04655e756b5f8b7d2d666d1379535..5dd3f06ca88cb28606d9fd2100ce03383c14d215 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -3,13 +3,17 @@
  * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
  */
 
+#define pr_fmt(fmt)	"reboot-mode: " fmt
+
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/reboot.h>
 #include <linux/reboot-mode.h>
+#include <linux/slab.h>
 
 #define PREFIX "mode-"
 
@@ -55,7 +59,9 @@ static int reboot_mode_notify(struct notifier_block *this,
 	unsigned int magic;
 
 	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
+	mutex_lock(&reboot->rb_lock);
 	magic = get_reboot_mode_magic(reboot, cmd);
+	mutex_unlock(&reboot->rb_lock);
 	if (magic)
 		reboot->write(reboot, magic);
 
@@ -65,45 +71,51 @@ static int reboot_mode_notify(struct notifier_block *this,
 /**
  * reboot_mode_register - register a reboot mode driver
  * @reboot: reboot mode driver
+ * @np: Pointer to device tree node
  *
  * Returns: 0 on success or a negative error code on failure.
  */
-int reboot_mode_register(struct reboot_mode_driver *reboot)
+int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np)
 {
 	struct mode_info *info;
+	struct mode_info *next;
 	struct property *prop;
-	struct device_node *np = reboot->dev->of_node;
 	size_t len = strlen(PREFIX);
 	int ret;
 
+	if (!np)
+		return -EINVAL;
+
 	INIT_LIST_HEAD(&reboot->head);
+	mutex_init(&reboot->rb_lock);
 
+	mutex_lock(&reboot->rb_lock);
 	for_each_property_of_node(np, prop) {
 		if (strncmp(prop->name, PREFIX, len))
 			continue;
 
-		info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
+		info = kzalloc(sizeof(*info), GFP_KERNEL);
 		if (!info) {
 			ret = -ENOMEM;
 			goto error;
 		}
 
 		if (of_property_read_u32(np, prop->name, &info->magic)) {
-			dev_err(reboot->dev, "reboot mode %s without magic number\n",
-				info->mode);
-			devm_kfree(reboot->dev, info);
+			pr_err("reboot mode %s without magic number\n", info->mode);
+			kfree(info);
 			continue;
 		}
 
 		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
 		if (!info->mode) {
 			ret =  -ENOMEM;
+			kfree(info);
 			goto error;
 		} else if (info->mode[0] == '\0') {
 			kfree_const(info->mode);
+			kfree(info);
 			ret = -EINVAL;
-			dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
-				prop->name);
+			pr_err("invalid mode name(%s): too short!\n", prop->name);
 			goto error;
 		}
 
@@ -113,12 +125,17 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
 	reboot->reboot_notifier.notifier_call = reboot_mode_notify;
 	register_reboot_notifier(&reboot->reboot_notifier);
 
+	mutex_unlock(&reboot->rb_lock);
 	return 0;
 
 error:
-	list_for_each_entry(info, &reboot->head, list)
+	list_for_each_entry_safe(info, next, &reboot->head, list) {
+		list_del(&info->list);
 		kfree_const(info->mode);
+		kfree(info);
+	}
 
+	mutex_unlock(&reboot->rb_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(reboot_mode_register);
@@ -130,11 +147,17 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
 int reboot_mode_unregister(struct reboot_mode_driver *reboot)
 {
 	struct mode_info *info;
+	struct mode_info *next;
 
 	unregister_reboot_notifier(&reboot->reboot_notifier);
 
-	list_for_each_entry(info, &reboot->head, list)
+	mutex_lock(&reboot->rb_lock);
+	list_for_each_entry_safe(info, next, &reboot->head, list) {
+		list_del(&info->list);
 		kfree_const(info->mode);
+		kfree(info);
+	}
+	mutex_unlock(&reboot->rb_lock);
 
 	return 0;
 }
@@ -162,7 +185,7 @@ int devm_reboot_mode_register(struct device *dev,
 	if (!dr)
 		return -ENOMEM;
 
-	rc = reboot_mode_register(reboot);
+	rc = reboot_mode_register(reboot, reboot->dev->of_node);
 	if (rc) {
 		devres_free(dr);
 		return rc;
diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..98f68f95c9e8460be23282c51ef7fcbed73887bd 100644
--- a/include/linux/reboot-mode.h
+++ b/include/linux/reboot-mode.h
@@ -2,14 +2,18 @@
 #ifndef __REBOOT_MODE_H__
 #define __REBOOT_MODE_H__
 
+#include <linux/mutex.h>
+
 struct reboot_mode_driver {
 	struct device *dev;
 	struct list_head head;
 	int (*write)(struct reboot_mode_driver *reboot, unsigned int magic);
 	struct notifier_block reboot_notifier;
+	/*Protects access to reboot mode list*/
+	struct mutex rb_lock;
 };
 
-int reboot_mode_register(struct reboot_mode_driver *reboot);
+int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *np);
 int reboot_mode_unregister(struct reboot_mode_driver *reboot);
 int devm_reboot_mode_register(struct device *dev,
 			      struct reboot_mode_driver *reboot);

-- 
2.34.1