zero.c

ARM S3C2410 USB SLAVE LINUX驱动

	/* two configurations will always be index 0 and index 1 */
	if (index > 1)
		return -EINVAL;
	is_source_sink = loopdefault ? (index == 1) : (index == 0);

#ifdef CONFIG_USB_GADGET_DUALSPEED
	if (type == USB_DT_OTHER_SPEED_CONFIG)
		hs = !hs;
	if (hs)
		function = is_source_sink
			? hs_source_sink_function
			: hs_loopback_function;
	else
#endif
		function = is_source_sink
			? fs_source_sink_function
			: fs_loopback_function;

	/* for now, don't advertise srp-only devices */
	if (!gadget->is_otg)
		function++;

	len = usb_gadget_config_buf (is_source_sink
					? &source_sink_config
					: &loopback_config,
			buf, USB_BUFSIZ, function);
	if (len < 0)
		return len;
	((struct usb_config_descriptor *) buf)->bDescriptorType = type;
	return len;
}

/*-------------------------------------------------------------------------*/

static struct usb_request *
alloc_ep_req (struct usb_ep *ep, unsigned length)
{
	struct usb_request	*req;

	req = usb_ep_alloc_request (ep, GFP_ATOMIC);
	if (req) {
		req->length = length;
		req->buf = usb_ep_alloc_buffer (ep, length,
				&req->dma, GFP_ATOMIC);
		if (!req->buf) {
			usb_ep_free_request (ep, req);
			req = NULL;
		}
	}
	return req;
}

static void free_ep_req (struct usb_ep *ep, struct usb_request *req)
{
	if (req->buf)
		usb_ep_free_buffer (ep, req->buf, req->dma, req->length);
	usb_ep_free_request (ep, req);
}

/*-------------------------------------------------------------------------*/

/* optionally require specific source/sink data patterns  */

static int
check_read_data (
	struct zero_dev		*dev,
	struct usb_ep		*ep,
	struct usb_request	*req
)
{
	unsigned	i;
	u8		*buf = req->buf;

	for (i = 0; i < req->actual; i++, buf++) {
		switch (pattern) {
		/* all-zeroes has no synchronization issues */
		case 0:
			if (*buf == 0)
				continue;
			break;
		/* mod63 stays in sync with short-terminated transfers,
		 * or otherwise when host and gadget agree on how large
		 * each usb transfer request should be.  resync is done
		 * with set_interface or set_config.
		 */
		case 1:
			if (*buf == (u8)(i % 63))
				continue;
			break;
		}
		ERROR (dev, "bad OUT byte, buf [%d] = %d\n", i, *buf);
		usb_ep_set_halt (ep);
		return -EINVAL;
	}
	return 0;
}

static void
reinit_write_data (
	struct zero_dev		*dev,
	struct usb_ep		*ep,
	struct usb_request	*req
)
{
	unsigned	i;
	u8		*buf = req->buf;

	switch (pattern) {
	case 0:
		memset (req->buf, 0, req->length);
		break;
	case 1:
		for  (i = 0; i < req->length; i++)
			*buf++ = (u8) (i % 63);
		break;
	}
}

/* if there is only one request in the queue, there'll always be an
 * irq delay between end of one request and start of the next.
 * that prevents using hardware dma queues.
 */
static void source_sink_complete (struct usb_ep *ep, struct usb_request *req)
{
	struct zero_dev	*dev = ep->driver_data;
	int		status = req->status;

	switch (status) {

	case 0: 			/* normal completion? */
		if (ep == dev->out_ep)
			check_read_data (dev, ep, req);
		else
			reinit_write_data (dev, ep, req);
		break;

	/* this endpoint is normally active while we're configured */
	case -ECONNABORTED: 		/* hardware forced ep reset */
	case -ECONNRESET:		/* request dequeued */
	case -ESHUTDOWN:		/* disconnect from host */
		VDBG (dev, "%s gone (%d), %d/%d\n", ep->name, status,
				req->actual, req->length);
		if (ep == dev->out_ep)
			check_read_data (dev, ep, req);
		free_ep_req (ep, req);
		return;

	case -EOVERFLOW:		/* buffer overrun on read means that
					 * we didn't provide a big enough
					 * buffer.
					 */
	default:
#if 1
		DBG (dev, "%s complete --> %d, %d/%d\n", ep->name,
				status, req->actual, req->length);
#endif
	case -EREMOTEIO:		/* short read */
		break;
	}

	status = usb_ep_queue (ep, req, GFP_ATOMIC);
	if (status) {
		ERROR (dev, "kill %s:  resubmit %d bytes --> %d\n",
				ep->name, req->length, status);
		usb_ep_set_halt (ep);
		/* FIXME recover later ... somehow */
	}
}

static struct usb_request *
source_sink_start_ep (struct usb_ep *ep, unsigned gfp_flags)
{
	struct usb_request	*req;
	int			status;

	req = alloc_ep_req (ep, buflen);
	if (!req)
		return NULL;

	memset (req->buf, 0, req->length);
	req->complete = source_sink_complete;

	if (strcmp (ep->name, EP_IN_NAME) == 0)
		reinit_write_data (ep->driver_data, ep, req);

	status = usb_ep_queue (ep, req, gfp_flags);
	if (status) {
		struct zero_dev	*dev = ep->driver_data;

		ERROR (dev, "start %s --> %d\n", ep->name, status);
		free_ep_req (ep, req);
		req = NULL;
	}

	return req;
}

static int
set_source_sink_config (struct zero_dev *dev, unsigned gfp_flags)
{
	int			result = 0;
	struct usb_ep		*ep;
	struct usb_gadget	*gadget = dev->gadget;

	gadget_for_each_ep (ep, gadget) {
		const struct usb_endpoint_descriptor	*d;

		/* one endpoint writes (sources) zeroes in (to the host) */
		if (strcmp (ep->name, EP_IN_NAME) == 0) {
			d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
			result = usb_ep_enable (ep, d);
			if (result == 0) {
				ep->driver_data = dev;
				if (source_sink_start_ep (ep, gfp_flags) != 0) {
					dev->in_ep = ep;
					continue;
				}
				usb_ep_disable (ep);
				result = -EIO;
			}

		/* one endpoint reads (sinks) anything out (from the host) */
		} else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
			d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
			result = usb_ep_enable (ep, d);
			if (result == 0) {
				ep->driver_data = dev;
				if (source_sink_start_ep (ep, gfp_flags) != 0) {
					dev->out_ep = ep;
					continue;
				}
				usb_ep_disable (ep);
				result = -EIO;
			}

		/* ignore any other endpoints */
		} else
			continue;

		/* stop on error */
		ERROR (dev, "can't start %s, result %d\n", ep->name, result);
		break;
	}
	if (result == 0)
		DBG (dev, "buflen %d\n", buflen);

	/* caller is responsible for cleanup on error */
	return result;
}

/*-------------------------------------------------------------------------*/

static void loopback_complete (struct usb_ep *ep, struct usb_request *req)
{
	struct zero_dev	*dev = ep->driver_data;
	int		status = req->status;

	switch (status) {

	case 0: 			/* normal completion? */
		if (ep == dev->out_ep) {
			/* loop this OUT packet back IN to the host */
			req->zero = (req->actual < req->length);
			req->length = req->actual;
			status = usb_ep_queue (dev->in_ep, req, GFP_ATOMIC);
			if (status == 0)
				return;

			/* "should never get here" */
			ERROR (dev, "can't loop %s to %s: %d\n",
				ep->name, dev->in_ep->name,
				status);
		}

		/* queue the buffer for some later OUT packet */
		req->length = buflen;
		status = usb_ep_queue (dev->out_ep, req, GFP_ATOMIC);
		if (status == 0)
			return;

		/* "should never get here" */
		/* FALLTHROUGH */

	default:
		ERROR (dev, "%s loop complete --> %d, %d/%d\n", ep->name,
				status, req->actual, req->length);
		/* FALLTHROUGH */

	/* NOTE:  since this driver doesn't maintain an explicit record
	 * of requests it submitted (just maintains qlen count), we
	 * rely on the hardware driver to clean up on disconnect or
	 * endpoint disable.
	 */
	case -ECONNABORTED: 		/* hardware forced ep reset */
	case -ECONNRESET:		/* request dequeued */
	case -ESHUTDOWN:		/* disconnect from host */
		free_ep_req (ep, req);
		return;
	}
}

static int
set_loopback_config (struct zero_dev *dev, unsigned gfp_flags)
{
	int			result = 0;
	struct usb_ep		*ep;
	struct usb_gadget	*gadget = dev->gadget;

	gadget_for_each_ep (ep, gadget) {
		const struct usb_endpoint_descriptor	*d;

		/* one endpoint writes data back IN to the host */
		if (strcmp (ep->name, EP_IN_NAME) == 0) {
			d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
			result = usb_ep_enable (ep, d);
			if (result == 0) {
				ep->driver_data = dev;
				dev->in_ep = ep;
				continue;
			}

		/* one endpoint just reads OUT packets */
		} else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
			d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
			result = usb_ep_enable (ep, d);
			if (result == 0) {
				ep->driver_data = dev;
				dev->out_ep = ep;
				continue;
			}

		/* ignore any other endpoints */
		} else
			continue;

		/* stop on error */
		ERROR (dev, "can't enable %s, result %d\n", ep->name, result);
		break;
	}

	/* allocate a bunch of read buffers and queue them all at once.
	 * we buffer at most 'qlen' transfers; fewer if any need more
	 * than 'buflen' bytes each.
	 */
	if (result == 0) {
		struct usb_request	*req;
		unsigned		i;

		ep = dev->out_ep;
		for (i = 0; i < qlen && result == 0; i++) {
			req = alloc_ep_req (ep, buflen);
			if (req) {
				req->complete = loopback_complete;
				result = usb_ep_queue (ep, req, GFP_ATOMIC);
				if (result)
					DBG (dev, "%s queue req --> %d\n",
							ep->name, result);
			} else
				result = -ENOMEM;
		}
	}
	if (result == 0)
		DBG (dev, "qlen %d, buflen %d\n", qlen, buflen);

	/* caller is responsible for cleanup on error */
	return result;
}

/*-------------------------------------------------------------------------*/

static void zero_reset_config (struct zero_dev *dev)
{
	if (dev->config == 0)
		return;

	DBG (dev, "reset config\n");

	/* just disable endpoints, forcing completion of pending i/o.
	 * all our completion handlers free their requests in this case.
	 */
	if (dev->in_ep) {
		usb_ep_disable (dev->in_ep);
		dev->in_ep = NULL;
	}
	if (dev->out_ep) {
		usb_ep_disable (dev->out_ep);
		dev->out_ep = NULL;
	}
	dev->config = 0;
	del_timer (&dev->resume);
}

/* change our operational config.  this code must agree with the code
 * that returns config descriptors, and altsetting code.
 *
 * it's also responsible for power management interactions. some
 * configurations might not work with our current power sources.
 *
 * note that some device controller hardware will constrain what this
 * code can do, perhaps by disallowing more than one configuration or
 * by limiting configuration choices (like the pxa2xx).
 */
static int
zero_set_config (struct zero_dev *dev, unsigned number, unsigned gfp_flags)
{
	int			result = 0;
	struct usb_gadget	*gadget = dev->gadget;

	if (number == dev->config)
		return 0;

	if (gadget_is_sa1100 (gadget) && dev->config) {
		/* tx fifo is full, but we can't clear it...*/
		INFO (dev, "can't change configurations\n");
		return -ESPIPE;
	}
	zero_reset_config (dev);

	switch (number) {
	case CONFIG_SOURCE_SINK:
		result = set_source_sink_config (dev, gfp_flags);
		break;
	case CONFIG_LOOPBACK:
		result = set_loopback_config (dev, gfp_flags);
		break;
	default:
		result = -EINVAL;
		/* FALL THROUGH */
	case 0:
		return result;
	}

	if (!result && (!dev->in_ep || !dev->out_ep))
		result = -ENODEV;
	if (result)
		zero_reset_config (dev);
	else {
		char *speed;

		switch (gadget->speed) {
		case USB_SPEED_LOW:	speed = "low"; break;
		case USB_SPEED_FULL:	speed = "full"; break;
		case USB_SPEED_HIGH:	speed = "high"; break;
		default: 		speed = "?"; break;