usb: u_data_bridge: Fix handling of USB RX requests

Currently on USB composition switch or USB cable disconnect,
USB RX requests are being added as part of read_queued list
instead of read_pool. In some cases it is seen that if port
bridge is trying to read data, those requests are requeued
and fails with -ESHUTDOWN, and again it continues with results
into watchdog timeout due to error log coming from read request
completion handler. Fix this by adding proper check in read
request completion handler.

Also reduce USB Tx/RX buffer size from PAGE_SIZE to 2048 bytes.
It also fixes issue where USB RX requests are not being queued
after USB composition switch.

CRs-Fixed: 854301
Change-Id: I3616dc35c093cfa19865891f46e7b1ccc7302573
Signed-off-by: Mayank Rana <mrana@codeaurora.org>

1 files changed, 25 insertions, 52 deletions

diff --git a/drivers/usb/gadget/function/u_data_bridge.c b/drivers/usb/gadget/function/u_data_bridge.c
index 944b770fa6c4..c4ef3e84edea 100644
--- a/drivers/usb/gadget/function/u_data_bridge.c
+++ b/drivers/usb/gadget/function/u_data_bridge.c
@@ -39,9 +39,9 @@
 #define num_of_instance 2
 
 #define BRIDGE_RX_QUEUE_SIZE	8
-#define BRIDGE_RX_BUF_SIZE	PAGE_SIZE
+#define BRIDGE_RX_BUF_SIZE	2048
 #define BRIDGE_TX_QUEUE_SIZE	8
-#define BRIDGE_TX_BUF_SIZE	PAGE_SIZE
+#define BRIDGE_TX_BUF_SIZE	2048
 
 struct gbridge_port {
 	struct cdev		gbridge_cdev;
@@ -62,7 +62,6 @@ struct gbridge_port {
 
 	unsigned		cbits_to_modem;
 	bool			cbits_updated;
-	unsigned		cbits_to_host;
 
 	bool			is_connected;
 	bool			port_open;
@@ -78,6 +77,7 @@ struct class *gbridge_classp;
 static dev_t gbridge_number;
 static struct workqueue_struct *gbridge_wq;
 static unsigned n_bridge_ports;
+static void gbridge_read_complete(struct usb_ep *ep, struct usb_request *req);
 static void gbridge_free_req(struct usb_ep *ep, struct usb_request *req)
 {
 	kfree(req->buf);
@@ -90,7 +90,7 @@ static void gbridge_free_requests(struct usb_ep *ep, struct list_head *head)
 
 	while (!list_empty(head)) {
 		req = list_entry(head->next, struct usb_request, list);
-		list_del(&req->list);
+		list_del_init(&req->list);
 		gbridge_free_req(ep, req);
 	}
 }
@@ -154,9 +154,9 @@ static void gbridge_start_rx(struct gbridge_port *port)
 	}
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	if (!port->port_usb) {
+	if (!(port->is_connected && port->port_open)) {
 		spin_unlock_irqrestore(&port->port_lock, flags);
-		pr_err("Err as USB is disconnected.\n");
+		pr_debug("can't start rx.\n");
 		return;
 	}
 
@@ -167,7 +167,9 @@ static void gbridge_start_rx(struct gbridge_port *port)
 		struct usb_request	*req;
 
 		req = list_entry(pool->next, struct usb_request, list);
-		list_del(&req->list);
+		list_del_init(&req->list);
+		req->length = BRIDGE_RX_BUF_SIZE;
+		req->complete = gbridge_read_complete;
 		spin_unlock_irqrestore(&port->port_lock, flags);
 		ret = usb_ep_queue(ep, req, GFP_KERNEL);
 		spin_lock_irqsave(&port->port_lock, flags);
@@ -195,17 +197,13 @@ static void gbridge_read_complete(struct usb_ep *ep, struct usb_request *req)
 	}
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	if (!port->port_open) {
+	if (!port->port_open || req->status || !req->actual) {
 		list_add_tail(&req->list, &port->read_pool);
 		spin_unlock_irqrestore(&port->port_lock, flags);
 		return;
 	}
 
-	if (!req->status)
-		port->nbytes_from_host += req->actual;
-	else
-		pr_warn("read_complete with status:%d\n", req->status);
-
+	port->nbytes_from_host += req->actual;
 	list_add_tail(&req->list, &port->read_queued);
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
@@ -303,20 +301,16 @@ static void gbridge_stop_io(struct gbridge_port *port)
 	out = port->port_usb->out;
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
-	usb_ep_fifo_flush(in);
-	usb_ep_fifo_flush(out);
+	/* disable endpoints, aborting down any active I/O */
+	usb_ep_disable(out);
+	out->driver_data = NULL;
+	usb_ep_disable(in);
+	in->driver_data = NULL;
 
 	spin_lock_irqsave(&port->port_lock, flags);
-	if (port->port_usb) {
-		gbridge_free_requests(out, &port->read_pool);
-		gbridge_free_requests(in, &port->write_pool);
-		port->cbits_to_host = 0;
-	}
-
-	if (port->port_usb->send_modem_ctrl_bits)
-		port->port_usb->send_modem_ctrl_bits(
-					port->port_usb,
-					port->cbits_to_host);
+	gbridge_free_requests(out, &port->read_queued);
+	gbridge_free_requests(out, &port->read_pool);
+	gbridge_free_requests(in, &port->write_pool);
 	spin_unlock_irqrestore(&port->port_lock, flags);
 }
 
@@ -325,7 +319,6 @@ int gbridge_port_open(struct inode *inode, struct file *file)
 	int ret;
 	unsigned long flags;
 	struct gbridge_port *port;
-	struct gserial *gser;
 
 	port = container_of(inode->i_cdev, struct gbridge_port,
 							gbridge_cdev);
@@ -350,11 +343,8 @@ int gbridge_port_open(struct inode *inode, struct file *file)
 
 	spin_lock_irqsave(&port->port_lock, flags);
 	port->port_open = true;
-	gser = port->port_usb;
 	spin_unlock_irqrestore(&port->port_lock, flags);
-	gbridge_start_io(port);
-	if (gser && gser->connect)
-		gser->connect(gser);
+	gbridge_start_rx(port);
 
 	pr_debug("port(%p) open is success\n", port);
 
@@ -365,7 +355,6 @@ int gbridge_port_release(struct inode *inode, struct file *file)
 {
 	unsigned long flags;
 	struct gbridge_port *port;
-	struct gserial *gser;
 
 	port = file->private_data;
 	if (!port) {
@@ -375,14 +364,10 @@ int gbridge_port_release(struct inode *inode, struct file *file)
 
 	pr_debug("closing port(%p)\n", port);
 	spin_lock_irqsave(&port->port_lock, flags);
-	gser = port->port_usb;
-	if (gser && gser->disconnect)
-		gser->disconnect(gser);
 
 	port->port_open = false;
 	port->cbits_updated = false;
 	spin_unlock_irqrestore(&port->port_lock, flags);
-	gbridge_stop_io(port);
 	pr_debug("port(%p) is closed.\n", port);
 
 	return 0;
@@ -471,7 +456,7 @@ ssize_t gbridge_port_write(struct file *file,
 	}
 	pool = &port->write_pool;
 	req = list_first_entry(pool, struct usb_request, list);
-	list_del(&req->list);
+	list_del_init(&req->list);
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
 	pr_debug("%s: write buf size:%zu\n", __func__, count);
@@ -710,13 +695,12 @@ static ssize_t debug_gbridge_read_stats(struct file *file, char __user *ubuf,
 				"nbytes_to_port_bridge:  %lu\n"
 				"nbytes_from_port_bridge: %lu\n"
 				"cbits_to_modem:  %u\n"
-				"cbits_to_host: %u\n"
 				"Port Opened: %s\n",
 				i, port->nbytes_to_host,
 				port->nbytes_from_host,
 				port->nbytes_to_port_bridge,
 				port->nbytes_from_port_bridge,
-				port->cbits_to_modem, port->cbits_to_host,
+				port->cbits_to_modem,
 				(port->port_open ? "Opened" : "Closed"));
 		spin_unlock_irqrestore(&port->port_lock, flags);
 	}
@@ -828,6 +812,7 @@ int gbridge_connect(void *gptr, u8 portno)
 	port->is_connected = true;
 	spin_unlock_irqrestore(&port->port_lock, flags);
 
+	gbridge_start_io(port);
 	wake_up(&port->open_wq);
 	return 0;
 }
@@ -852,25 +837,13 @@ void gbridge_disconnect(void *gptr, u8 portno)
 	port = ports[portno];
 	gser = gptr;
 
+	gbridge_stop_io(port);
 	spin_lock_irqsave(&port->port_lock, flags);
 	port->is_connected = false;
-	port->port_usb = 0;
-	spin_unlock_irqrestore(&port->port_lock, flags);
-
-	/* disable endpoints, aborting down any active I/O */
-	usb_ep_disable(gser->out);
-	gser->out->driver_data = NULL;
-	usb_ep_disable(gser->in);
-	gser->in->driver_data = NULL;
-
-	spin_lock_irqsave(&port->port_lock, flags);
-	gbridge_free_requests(gser->out, &port->read_pool);
-	gbridge_free_requests(gser->in, &port->write_pool);
-
+	port->port_usb = NULL;
 	port->nbytes_from_host = port->nbytes_to_host = 0;
 	port->nbytes_to_port_bridge = 0;
 	spin_unlock_irqrestore(&port->port_lock, flags);
-
 }
 
 static void gbridge_port_free(int portno)