[PATCH v2 3/6] platform/chrome: Disallow sending commands through unregistered ec_dev

[Tzung-Bi Shih <tzungbi@kernel.org>]

Return earlier if attempting to send commands through an unregistered
struct cros_ec_device.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
New patch in the v2 series.

 drivers/platform/chrome/cros_ec.c           | 6 ++++++
 drivers/platform/chrome/cros_ec_proto.c     | 6 ++++++
 include/linux/platform_data/cros_ec_proto.h | 2 ++
 3 files changed, 14 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 110771a8645e..ea877f44665c 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -200,6 +200,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	if (!ec_dev->dout)
 		return -ENOMEM;
 
+	ec_dev->registered = true;
 	lockdep_register_key(&ec_dev->lockdep_key);
 	mutex_init(&ec_dev->lock);
 	lockdep_set_class(&ec_dev->lock, &ec_dev->lockdep_key);
@@ -300,6 +301,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 
 	return 0;
 exit:
+	ec_dev->registered = false;
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
 	mutex_destroy(&ec_dev->lock);
@@ -318,6 +320,10 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
+	mutex_lock(&ec_dev->lock);
+	ec_dev->registered = false;
+	mutex_unlock(&ec_dev->lock);
+
 	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 3e94a0a82173..3d657d990c4a 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -657,6 +657,12 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
 	int ret;
 
 	mutex_lock(&ec_dev->lock);
+	if (!ec_dev->registered) {
+		dev_err(ec_dev->dev, "unregistered ec_dev; cannot send command\n");
+		mutex_unlock(&ec_dev->lock);
+		return -ENODEV;
+	}
+
 	if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
 		ret = cros_ec_query_all(ec_dev);
 		if (ret) {
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index 3ec24f445c29..2722290688e6 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -122,6 +122,7 @@ struct cros_ec_command {
  * @dout_size: Size of dout buffer to allocate (zero to use static dout).
  * @wake_enabled: True if this device can wake the system from sleep.
  * @suspended: True if this device had been suspended.
+ * @registered: True if this device had been registered.
  * @cmd_xfer: Send command to EC and get response.
  *            Returns the number of bytes received if the communication
  *            succeeded, but that doesn't mean the EC was happy with the
@@ -180,6 +181,7 @@ struct cros_ec_device {
 	int dout_size;
 	bool wake_enabled;
 	bool suspended;
+	bool registered;
 	int (*cmd_xfer)(struct cros_ec_device *ec,
 			struct cros_ec_command *msg);
 	int (*pkt_xfer)(struct cros_ec_device *ec,
-- 
2.50.0.727.gbf7dc18ff4-goog