power: reset: reboot-mode: support parse boot mode

Parse boot mode on system bootup, and export it to
userspace by sysfs: sys/kernel/boot_mode

Change-Id: I0158fc28f4dae51c798806006e49cead4ce2e923
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>

drivers/power/reset/reboot-mode.c

@@ -10,9 +10,11 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/kobject.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/reboot.h>
+#include <linux/sysfs.h>
 #include "reboot-mode.h"
 
 #define PREFIX "mode-"
@@ -26,9 +28,21 @@ struct mode_info {
 struct reboot_mode_driver {
 	struct list_head head;
 	int (*write)(int magic);
+	int (*read)(void);
 	struct notifier_block reboot_notifier;
+	struct notifier_block panic_notifier;
 };
 
+static char *boot_mode = "coldboot";
+
+static ssize_t boot_mode_show(struct kobject *kobj, struct kobj_attribute *attr,
+			      char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%s\n", boot_mode);
+}
+
+static struct kobj_attribute kobj_boot_mode = __ATTR_RO(boot_mode);
+
 static int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 				 const char *cmd)
 {
@@ -49,23 +63,60 @@ static int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 	return magic;
 }
 
-static int reboot_mode_notify(struct notifier_block *this,
-			      unsigned long mode, void *cmd)
+static void reboot_mode_write(struct reboot_mode_driver *reboot,
+			      const void *cmd)
 {
-	struct reboot_mode_driver *reboot;
 	int magic;
 
-	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
 	magic = get_reboot_mode_magic(reboot, cmd);
 	if (!magic)
 		magic = get_reboot_mode_magic(reboot, NULL);
 	if (magic)
 		reboot->write(magic);
+}
+
+static int reboot_mode_notify(struct notifier_block *this,
+			      unsigned long mode, void *cmd)
+{
+	struct reboot_mode_driver *reboot;
+
+	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
+	reboot_mode_write(reboot, cmd);
 
 	return NOTIFY_DONE;
 }
 
-int reboot_mode_register(struct device *dev, int (*write)(int))
+static int reboot_mode_panic_notify(struct notifier_block *this,
+				      unsigned long ev, void *ptr)
+{
+	struct reboot_mode_driver *reboot;
+	const char *cmd = "panic";
+
+	reboot = container_of(this, struct reboot_mode_driver, panic_notifier);
+	reboot_mode_write(reboot, cmd);
+
+	return NOTIFY_DONE;
+}
+
+static int boot_mode_parse(struct reboot_mode_driver *reboot)
+{
+	struct mode_info *info;
+	unsigned int magic = reboot->read();
+
+	list_for_each_entry(info, &reboot->head, list) {
+		if (info->magic == magic) {
+			boot_mode = info->mode;
+			break;
+		}
+	}
+
+	pr_info("Boot mode: %s\n", boot_mode);
+
+	return 0;
+}
+
+int reboot_mode_register(struct device *dev, int (*write)(int),
+			 int (*read)(void))
 {
 	struct reboot_mode_driver *reboot;
 	struct mode_info *info;
@@ -78,6 +129,7 @@ int reboot_mode_register(struct device *dev, int (*write)(int))
 		return -ENOMEM;
 
 	reboot->write = write;
+	reboot->read = read;
 	INIT_LIST_HEAD(&reboot->head);
 	for_each_property_of_node(dev->of_node, prop) {
 		if (len > strlen(prop->name) || strncmp(prop->name, PREFIX, len))
@@ -94,10 +146,13 @@ int reboot_mode_register(struct device *dev, int (*write)(int))
 		}
 		list_add_tail(&info->list, &reboot->head);
 	}
+	boot_mode_parse(reboot);
 	reboot->reboot_notifier.notifier_call = reboot_mode_notify;
+	reboot->panic_notifier.notifier_call = reboot_mode_panic_notify;
 	ret = register_reboot_notifier(&reboot->reboot_notifier);
-	if (ret)
-		dev_err(dev, "can't register reboot notifier\n");
+	ret += atomic_notifier_chain_register(&panic_notifier_list,
+				       &reboot->panic_notifier);
+	ret += sysfs_create_file(kernel_kobj, &kobj_boot_mode.attr);
 
 	return ret;
 }

drivers/power/reset/reboot-mode.h

@@ -2,6 +2,7 @@
 #ifndef __REBOOT_MODE_H__
 #define __REBOOT_MODE_H__
 
-int reboot_mode_register(struct device *dev, int (*write)(int));
+int reboot_mode_register(struct device *dev, int (*write)(int),
+			 int (*read)(void));
 
 #endif

drivers/power/reset/syscon-reboot-mode.c

@@ -29,6 +29,15 @@ static int syscon_reboot_mode_write(int magic)
 	return 0;
 }
 
+static int syscon_reboot_mode_read(void)
+{
+	u32 val = 0;
+
+	regmap_read(map, offset, &val);
+
+	return val;
+}
+
 static int syscon_reboot_mode_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -39,7 +48,8 @@ static int syscon_reboot_mode_probe(struct platform_device *pdev)
 	if (of_property_read_u32(pdev->dev.of_node, "offset", &offset))
 		return -EINVAL;
 	of_property_read_u32(pdev->dev.of_node, "mask", &mask);
-	ret = reboot_mode_register(&pdev->dev, syscon_reboot_mode_write);
+	ret = reboot_mode_register(&pdev->dev, syscon_reboot_mode_write,
+				   syscon_reboot_mode_read);
 	if (ret)
 		dev_err(&pdev->dev, "can't register reboot mode\n");