Skip authentication for Mad Catz devices

See code comments.

Author: medusalix

auth/auth.c

@@ -486,18 +486,25 @@ static void gip_auth_exchange_rsa(struct work_struct *work)
 			__func__, err);
 }
 
+int gip_auth_send_complete(struct gip_client *client)
+{
+	struct gip_auth_header_control hdr = {};
+
+	hdr.context = GIP_AUTH_CTX_CONTROL;
+	hdr.control = GIP_AUTH_CTRL_COMPLETE;
+
+	return gip_send_authenticate(client, &hdr, sizeof(hdr), false);
+}
+EXPORT_SYMBOL_GPL(gip_auth_send_complete);
+
 static void gip_auth_complete_handshake(struct work_struct *work)
 {
 	struct gip_auth *auth = container_of(work, typeof(*auth),
 					     work_complete);
-	struct gip_auth_header_control hdr = {};
 	u8 random[GIP_AUTH_RANDOM_LEN * 2];
 	u8 key[GIP_AUTH_SESSION_KEY_LEN];
 	int err;
 
-	hdr.context = GIP_AUTH_CTX_CONTROL;
-	hdr.control = GIP_AUTH_CTRL_COMPLETE;
-
 	memcpy(random, auth->random_host, sizeof(auth->random_host));
 	memcpy(random + sizeof(auth->random_host), auth->random_client,
 	       sizeof(auth->random_client));
@@ -517,9 +524,9 @@ static void gip_auth_complete_handshake(struct work_struct *work)
 	dev_dbg(&auth->client->dev, "%s: key=%*phD\n", __func__,
 		(int)sizeof(key), key);
 
-	err = gip_send_authenticate(auth->client, &hdr, sizeof(hdr), false);
+	err = gip_auth_send_complete(auth->client);
 	if (err) {
-		dev_err(&auth->client->dev, "%s: send pkt failed: %d\n",
+		dev_err(&auth->client->dev, "%s: send complete failed: %d\n",
 			__func__, err);
 		return;
 	}

auth/auth.h

@@ -44,5 +44,6 @@ struct gip_auth {
 	u8 master_secret[GIP_AUTH_SECRET_LEN];
 };
 
+int gip_auth_send_complete(struct gip_client *client);
 int gip_auth_process_pkt(struct gip_auth *auth, void *data, u32 len);
 int gip_auth_start_handshake(struct gip_auth *auth, struct gip_client *client);

driver/madcatz_glam.c

@@ -48,7 +48,6 @@ struct gip_glam_pkt_input {
 struct gip_glam {
 	struct gip_client *client;
 	struct gip_battery battery;
-	struct gip_auth auth;
 	struct gip_input input;
 };
 
@@ -95,14 +94,6 @@ static int gip_glam_op_battery(struct gip_client *client,
 	return 0;
 }
 
-static int gip_glam_op_authenticate(struct gip_client *client,
-				    void *data, u32 len)
-{
-	struct gip_glam *glam = dev_get_drvdata(&client->dev);
-
-	return gip_auth_process_pkt(&glam->auth, data, len);
-}
-
 static int gip_glam_op_guide_button(struct gip_client *client, bool down)
 {
 	struct gip_glam *glam = dev_get_drvdata(&client->dev);
@@ -172,7 +163,14 @@ static int gip_glam_probe(struct gip_client *client)
 	if (err)
 		return err;
 
-	err = gip_auth_start_handshake(&glam->auth, client);
+	/*
+	 * The Drum Kit sends auth chunks without specifying the
+	 * acknowledgment option while still expecting an acknowledgment.
+	 * The Windows driver handles this by sending an acknowledgment
+	 * after 100 ms when no further chunks are received.
+	 * We skip the handshake instead, as it is not required.
+	 */
+	err = gip_auth_send_complete(client);
 	if (err)
 		return err;
 
@@ -194,7 +192,6 @@ static struct gip_driver gip_glam_driver = {
 	.class = "MadCatz.Xbox.Drums.Glam",
 	.ops = {
 		.battery = gip_glam_op_battery,
-		.authenticate = gip_glam_op_authenticate,
 		.guide_button = gip_glam_op_guide_button,
 		.input = gip_glam_op_input,
 	},

driver/madcatz_strat.c

@@ -39,7 +39,6 @@ struct gip_strat_pkt_input {
 struct gip_strat {
 	struct gip_client *client;
 	struct gip_battery battery;
-	struct gip_auth auth;
 	struct gip_input input;
 };
 
@@ -86,14 +85,6 @@ static int gip_strat_op_battery(struct gip_client *client,
 	return 0;
 }
 
-static int gip_strat_op_authenticate(struct gip_client *client,
-				     void *data, u32 len)
-{
-	struct gip_strat *strat = dev_get_drvdata(&client->dev);
-
-	return gip_auth_process_pkt(&strat->auth, data, len);
-}
-
 static int gip_strat_op_guide_button(struct gip_client *client, bool down)
 {
 	struct gip_strat *strat = dev_get_drvdata(&client->dev);
@@ -169,7 +160,14 @@ static int gip_strat_probe(struct gip_client *client)
 	if (err)
 		return err;
 
-	err = gip_auth_start_handshake(&strat->auth, client);
+	/*
+	 * The Stratocaster sends auth chunks without specifying the
+	 * acknowledgment option while still expecting an acknowledgment.
+	 * The Windows driver handles this by sending an acknowledgment
+	 * after 100 ms when no further chunks are received.
+	 * We skip the handshake instead, as it is not required.
+	 */
+	err = gip_auth_send_complete(client);
 	if (err)
 		return err;
 
@@ -191,7 +189,6 @@ static struct gip_driver gip_strat_driver = {
 	.class = "MadCatz.Xbox.Guitar.Stratocaster",
 	.ops = {
 		.battery = gip_strat_op_battery,
-		.authenticate = gip_strat_op_authenticate,
 		.guide_button = gip_strat_op_guide_button,
 		.input = gip_strat_op_input,
 	},