Commit f371e750 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
Browse files

usb serial gadget: CDC ACM fixes 



Based on a patch from <Aurel.Thomi@ruag.com>, this makes the
CDC-ACM support in the serial gadget handle the SET_LINE_CODING
and SET_CONTROL_LINE_STATE requests ... which should improve
interop with at least MS-Windows "usbser.sys" if not some other
ACM host drivers.

It also adds a few REVISIT comments where this code plays a bit
loose with the CDC ACM spec.  If this were used to hook up to a
real RS232 or modem link, those places would need a bit of work.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d75379a5

drivers/usb/gadget/serial.c

+73 −17
Original line number Diff line number Diff line
@@ -135,7 +135,10 @@ struct gs_port { 
	int			port_in_use;	/* open/close in progress */

	wait_queue_head_t	port_write_wait;/* waiting to write */

	struct gs_buf		*port_write_buf;

	struct usb_cdc_line_coding	port_line_coding;

	struct usb_cdc_line_coding port_line_coding;	/* 8-N-1 etc */

	u16			port_handshake_bits;

#define RS232_RTS	(1 << 1)

#define RS232_DTE	(1 << 0)

};



/* the device structure holds info for the USB device */
@@ -199,6 +202,8 @@ static int gs_setup_standard(struct usb_gadget *gadget, 
static int gs_setup_class(struct usb_gadget *gadget,

	const struct usb_ctrlrequest *ctrl);

static void gs_setup_complete(struct usb_ep *ep, struct usb_request *req);

static void gs_setup_complete_set_line_coding(struct usb_ep *ep,

	struct usb_request *req);

static void gs_disconnect(struct usb_gadget *gadget);

static int gs_set_config(struct gs_dev *dev, unsigned config);

static void gs_reset_config(struct gs_dev *dev);
@@ -406,7 +411,7 @@ static struct usb_cdc_acm_descriptor gs_acm_descriptor = { 
	.bLength =		sizeof(gs_acm_descriptor),

	.bDescriptorType =	USB_DT_CS_INTERFACE,

	.bDescriptorSubType =	USB_CDC_ACM_TYPE,

	.bmCapabilities =	0,

	.bmCapabilities =	(1 << 1),

};



static const struct usb_cdc_union_desc gs_union_desc = {
@@ -1502,6 +1507,8 @@ static int gs_setup(struct usb_gadget *gadget, 
	u16 wValue = le16_to_cpu(ctrl->wValue);

	u16 wLength = le16_to_cpu(ctrl->wLength);



	req->complete = gs_setup_complete;



	switch (ctrl->bRequestType & USB_TYPE_MASK) {

	case USB_TYPE_STANDARD:

		ret = gs_setup_standard(gadget,ctrl);
@@ -1679,18 +1686,14 @@ static int gs_setup_class(struct usb_gadget *gadget, 


	switch (ctrl->bRequest) {

	case USB_CDC_REQ_SET_LINE_CODING:

		/* FIXME Submit req to read the data; have its completion

		 * handler copy that data to port->port_line_coding (iff

		 * it's valid) and maybe pass it on.  Until then, fail.

		 */

		pr_warning("gs_setup: set_line_coding "

				"unuspported\n");

		if (wLength != sizeof(struct usb_cdc_line_coding))

			break;

		ret = wLength;

		req->complete = gs_setup_complete_set_line_coding;

		break;



	case USB_CDC_REQ_GET_LINE_CODING:

		port = dev->dev_port[0];	/* ACM only has one port */

		ret = min(wLength,

			(u16)sizeof(struct usb_cdc_line_coding));

		ret = min_t(int, wLength, sizeof(struct usb_cdc_line_coding));

		if (port) {

			spin_lock(&port->port_lock);

			memcpy(req->buf, &port->port_line_coding, ret);
@@ -1699,15 +1702,27 @@ static int gs_setup_class(struct usb_gadget *gadget, 
		break;



	case USB_CDC_REQ_SET_CONTROL_LINE_STATE:

		/* FIXME Submit req to read the data; have its completion

		 * handler use that to set the state (iff it's valid) and

		 * maybe pass it on.  Until then, fail.

		if (wLength != 0)

			break;

		ret = 0;

		if (port) {

			/* REVISIT:  we currently just remember this data.

			 * If we change that, update whatever hardware needs

			 * updating.

			 */

		pr_warning("gs_setup: set_control_line_state "

				"unuspported\n");

			spin_lock(&port->port_lock);

			port->port_handshake_bits = wValue;

			spin_unlock(&port->port_lock);

		}

		break;



	default:

		/* NOTE:  strictly speaking, we should accept AT-commands

		 * using SEND_ENCPSULATED_COMMAND/GET_ENCAPSULATED_RESPONSE.

		 * But our call management descriptor says we don't handle

		 * call management, so we should be able to get by without

		 * handling those "required" commands (except by stalling).

		 */

		pr_err("gs_setup: unknown class request, "

				"type=%02x, request=%02x, value=%04x, "

				"index=%04x, length=%d\n",
@@ -1719,6 +1734,42 @@ static int gs_setup_class(struct usb_gadget *gadget, 
	return ret;

}



static void gs_setup_complete_set_line_coding(struct usb_ep *ep,

		struct usb_request *req)

{

	struct gs_dev *dev = ep->driver_data;

	struct gs_port *port = dev->dev_port[0]; /* ACM only has one port */



	switch (req->status) {

	case 0:

		/* normal completion */

		if (req->actual != sizeof(port->port_line_coding))

			usb_ep_set_halt(ep);

		else if (port) {

			struct usb_cdc_line_coding	*value = req->buf;



			/* REVISIT:  we currently just remember this data.

			 * If we change that, (a) validate it first, then

			 * (b) update whatever hardware needs updating.

			 */

			spin_lock(&port->port_lock);

			port->port_line_coding = *value;

			spin_unlock(&port->port_lock);

		}

		break;



	case -ESHUTDOWN:

		/* disconnect */

		gs_free_req(ep, req);

		break;



	default:

		/* unexpected */

		break;

	}

	return;

}



/*

 * gs_setup_complete

 */
@@ -1906,6 +1957,11 @@ static int gs_set_config(struct gs_dev *dev, unsigned config) 
		}

	}



	/* REVISIT the ACM mode should be able to actually *issue* some

	 * notifications, for at least serial state change events if

	 * not also for network connection; say so in bmCapabilities.

	 */



	pr_info("gs_set_config: %s configured, %s speed %s config\n",

		GS_LONG_NAME,

		gadget->speed == USB_SPEED_HIGH ? "high" : "full",

CRA Git | Maintained and supported by SUSTech CRA and CCSE