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

@@ -10,10 +10,12 @@
 #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/reboot-mode.h>
+#include <linux/sysfs.h>
 
 #define PREFIX "mode-"
 
@@ -23,8 +25,18 @@ struct mode_info {
 	struct list_head list;
 };
 
-static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
-					  const char *cmd)
+static const 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)
 {
 	const char *normal = "normal";
 	int magic = 0;
@@ -43,20 +55,54 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 	return magic;
 }
 
+static void reboot_mode_write(struct reboot_mode_driver *reboot,
+			      const void *cmd)
+{
+	int magic;
+
+	magic = get_reboot_mode_magic(reboot, cmd);
+	if (magic)
+		reboot->write(reboot, magic);
+}
+
 static int reboot_mode_notify(struct notifier_block *this,
 			      unsigned long mode, void *cmd)
 {
 	struct reboot_mode_driver *reboot;
-	unsigned int magic;
 
 	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
-	magic = get_reboot_mode_magic(reboot, cmd);
-	if (magic)
-		reboot->write(reboot, magic);
+	reboot_mode_write(reboot, cmd);
 
 	return NOTIFY_DONE;
 }
 
+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(reboot);
+
+	list_for_each_entry(info, &reboot->head, list) {
+		if (info->magic == magic) {
+			boot_mode = info->mode;
+			break;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * reboot_mode_register - register a reboot mode driver
  * @reboot: reboot mode driver
@@ -105,10 +151,15 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
 		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;
 	register_reboot_notifier(&reboot->reboot_notifier);
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &reboot->panic_notifier);
+	ret = sysfs_create_file(kernel_kobj, &kobj_boot_mode.attr);
 
-	return 0;
+	return ret;
 
 error:
 	list_for_each_entry(info, &reboot->head, list)

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

@@ -40,6 +40,17 @@ static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
 	return ret;
 }
 
+static int syscon_reboot_mode_read(struct reboot_mode_driver *reboot)
+{
+	struct syscon_reboot_mode *syscon_rbm;
+	u32 val = 0;
+
+	syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
+	regmap_read(syscon_rbm->map, syscon_rbm->offset, &val);
+
+	return val;
+}
+
 static int syscon_reboot_mode_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -51,6 +62,7 @@ static int syscon_reboot_mode_probe(struct platform_device *pdev)
 
 	syscon_rbm->reboot.dev = &pdev->dev;
 	syscon_rbm->reboot.write = syscon_reboot_mode_write;
+	syscon_rbm->reboot.read = syscon_reboot_mode_read;
 	syscon_rbm->mask = 0xffffffff;
 
 	syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node);

include/linux/reboot-mode.h

@@ -6,7 +6,9 @@ struct reboot_mode_driver {
 	struct device *dev;
 	struct list_head head;
 	int (*write)(struct reboot_mode_driver *reboot, unsigned int magic);
+	int (*read)(struct reboot_mode_driver *reboot);
 	struct notifier_block reboot_notifier;
+	struct notifier_block panic_notifier;
 };
 
 int reboot_mode_register(struct reboot_mode_driver *reboot);