[PATCH v10 03/10] power: reset: reboot-mode: Add optional cookie argument

[Shivendra Pratap]

Current reboot-mode driver supports a single argument(magic) for
each reboot-mode. There may be uses-cases where a mode requires
an additional argument and hence may not be able to use the
reboot-mode driver. For example, ARM PSCI vendor-specific resets,
need two arguments for its operation – reset_type and cookie, to
complete the reset operation. If a driver wants to implement this
firmware-based reset, it cannot use reboot-mode framework.

Add support for storing an additional optional argument (cookie)
for each reboot-mode and introduce a write function in
reboot-mode that writes two arguments for each reboot-mode
command. Implement the read and store of additional cookie value
for each reboot-mode defined in the device tree. In case there is
no cookie specified in the reboot-mode device tree, mark the
cookie as invalid to support backward compatibility.

Signed-off-by: Shivendra Pratap <shivendra.pratap at oss.qualcomm.com>
---
 drivers/power/reset/reboot-mode.c | 32 ++++++++++++++++++++++----------
 include/linux/reboot-mode.h       |  2 ++
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index 61f647b23959789a313f3af0bd967abcad45fa43..afadd823d62d0f7e7e645746b978cc8fecfb9ac4 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -17,11 +17,12 @@
 struct mode_info {
 	const char *mode;
 	u32 magic;
+	u32 cookie;
+	bool is_cookie_valid;
 	struct list_head list;
 };
 
-static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
-					  const char *cmd)
+static struct mode_info *get_reboot_mode_info(struct reboot_mode_driver *reboot, const char *cmd)
 {
 	const char *normal = "normal";
 	struct mode_info *info;
@@ -32,11 +33,11 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 
 	list_for_each_entry(info, &reboot->head, list)
 		if (!strcmp(info->mode, cmd))
-			return info->magic;
+			return info;
 
 	/* try to match again, replacing characters impossible in DT */
 	if (strscpy(cmd_, cmd, sizeof(cmd_)) == -E2BIG)
-		return 0;
+		return NULL;
 
 	strreplace(cmd_, ' ', '-');
 	strreplace(cmd_, ',', '-');
@@ -44,21 +45,27 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
 
 	list_for_each_entry(info, &reboot->head, list)
 		if (!strcmp(info->mode, cmd_))
-			return info->magic;
+			return info;
 
-	return 0;
+	return NULL;
 }
 
 static int reboot_mode_notify(struct notifier_block *this,
 			      unsigned long mode, void *cmd)
 {
 	struct reboot_mode_driver *reboot;
-	unsigned int magic;
+	struct mode_info *info;
 
 	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
-	magic = get_reboot_mode_magic(reboot, cmd);
-	if (magic)
-		reboot->write(reboot, magic);
+	info = get_reboot_mode_info(reboot, cmd);
+	if (info) {
+		if (info->is_cookie_valid) {
+			reboot->write_with_cookie(reboot, info->magic, info->cookie);
+		} else {
+			if (info->magic)
+				reboot->write(reboot, info->magic);
+		}
+	}
 
 	return NOTIFY_DONE;
 }
@@ -95,6 +102,11 @@ int reboot_mode_register(struct reboot_mode_driver *reboot, struct device_node *
 			continue;
 		}
 
+		if (of_property_read_u32_index(np, prop->name, 1, &info->cookie))
+			info->is_cookie_valid = false;
+		else
+			info->is_cookie_valid = true;
+
 		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
 		if (!info->mode) {
 			ret =  -ENOMEM;
diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
index 36f071f4b82e1fc255d8dd679a18e537655c3179..cfe18cdc2559be249969bba6c022940a508dd188 100644
--- a/include/linux/reboot-mode.h
+++ b/include/linux/reboot-mode.h
@@ -6,6 +6,8 @@ struct reboot_mode_driver {
 	struct device *dev;
 	struct list_head head;
 	int (*write)(struct reboot_mode_driver *reboot, unsigned int magic);
+	int (*write_with_cookie)(struct reboot_mode_driver *reboot,
+				 unsigned int magic, unsigned int cookie);
 	struct notifier_block reboot_notifier;
 };
 

-- 
2.34.1