inode.c

LINUX2.4.18内核下的usb GADGET驱动程序

	}
	buf += 4;
	len -= 4;

	/* NOTE:  audio endpoint extensions not accepted here;
	 * just don't include the extra bytes.
	 */

	/* full/low speed descriptor, then high speed */
	if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
		goto fail1;
	}
	if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
			|| data->desc.bDescriptorType != USB_DT_ENDPOINT)
		goto fail0;
	if (len != USB_DT_ENDPOINT_SIZE) {
		if (len != 2 * USB_DT_ENDPOINT_SIZE)
			goto fail0;
		if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
					USB_DT_ENDPOINT_SIZE)) {
			goto fail1;
		}
		if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
				|| data->hs_desc.bDescriptorType
					!= USB_DT_ENDPOINT) {
			DBG(data->dev, "config %s, bad hs length or type\n",
					data->name);
			goto fail0;
		}
	}
	value = len;

	spin_lock_irq (&data->dev->lock);
	if (data->dev->state == STATE_DEV_UNBOUND) {
		value = -ENOENT;
		goto gone;
	} else if ((ep = data->ep) == NULL) {
		value = -ENODEV;
		goto gone;
	}
	switch (data->dev->gadget->speed) {
	case USB_SPEED_LOW:
	case USB_SPEED_FULL:
		value = usb_ep_enable (ep, &data->desc);
		if (value == 0)
			data->state = STATE_EP_ENABLED;
		break;
#ifdef	HIGHSPEED
	case USB_SPEED_HIGH:
		/* fails if caller didn't provide that descriptor... */
		value = usb_ep_enable (ep, &data->hs_desc);
		if (value == 0)
			data->state = STATE_EP_ENABLED;
		break;
#endif
	default:
		DBG (data->dev, "unconnected, %s init deferred\n",
				data->name);
		data->state = STATE_EP_DEFER_ENABLE;
	}
	if (value == 0)
		fd->f_op = &ep_io_operations;
gone:
	spin_unlock_irq (&data->dev->lock);
	if (value < 0) {
fail:
		data->desc.bDescriptorType = 0;
		data->hs_desc.bDescriptorType = 0;
	}
	up (&data->lock);
	return value;
fail0:
	value = -EINVAL;
	goto fail;
fail1:
	value = -EFAULT;
	goto fail;
}

static int
ep_open (struct inode *inode, struct file *fd)
{
	struct ep_data		*data = inode->u.generic_ip;
	int			value = -EBUSY;

	if (down_interruptible (&data->lock) != 0)
		return -EINTR;
	spin_lock_irq (&data->dev->lock);
	if (data->dev->state == STATE_DEV_UNBOUND)
		value = -ENOENT;
	else if (data->state == STATE_EP_DISABLED) {
		value = 0;
		data->state = STATE_EP_READY;
		get_ep (data);
		fd->private_data = data;
		VDEBUG (data->dev, "%s ready\n", data->name);
	} else
		DBG (data->dev, "%s state %d\n",
			data->name, data->state);
	spin_unlock_irq (&data->dev->lock);
	up (&data->lock);
	return value;
}

/* used before endpoint configuration */
static struct file_operations ep_config_operations = {
	.owner =	THIS_MODULE,
	.open =		ep_open,
	.write =	ep_config,
	.release =	ep_release,
};

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

/* EP0 IMPLEMENTATION can be partly in userspace.
 *
 * Drivers that use this facility receive various events, including
 * control requests the kernel doesn't handle.  Drivers that don't
 * use this facility may be too simple-minded for real applications.
 */

static inline void ep0_readable (struct dev_data *dev)
{
	wake_up (&dev->wait);
	kill_fasync (&dev->fasync, SIGIO, POLL_IN);
}

static void clean_req (struct usb_ep *ep, struct usb_request *req)
{
	struct dev_data		*dev = ep->driver_data;

	if (req->buf != dev->rbuf) {
		usb_ep_free_buffer (ep, req->buf, req->dma, req->length);
		req->buf = dev->rbuf;
		req->dma = DMA_ADDR_INVALID;
	}
	req->complete = epio_complete;
	dev->setup_out_ready = 0;
}

static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
{
	struct dev_data		*dev = ep->driver_data;
	int			free = 1;

	/* for control OUT, data must still get to userspace */
	if (!dev->setup_in) {
		dev->setup_out_error = (req->status != 0);
		if (!dev->setup_out_error)
			free = 0;
		dev->setup_out_ready = 1;
		ep0_readable (dev);
	} else if (dev->state == STATE_SETUP)
		dev->state = STATE_CONNECTED;

	/* clean up as appropriate */
	if (free && req->buf != &dev->rbuf)
		clean_req (ep, req);
	req->complete = epio_complete;
}

static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
{
	struct dev_data	*dev = ep->driver_data;

	if (dev->setup_out_ready) {
		DBG (dev, "ep0 request busy!\n");
		return -EBUSY;
	}
	if (len > sizeof (dev->rbuf))
		req->buf = usb_ep_alloc_buffer (ep, len, &req->dma, GFP_ATOMIC);
	if (req->buf == 0) {
		req->buf = dev->rbuf;
		return -ENOMEM;
	}
	req->complete = ep0_complete;
	req->length = len;
	return 0;
}

static ssize_t
ep0_read (struct file *fd, char *buf, size_t len, loff_t *ptr)
{
	struct dev_data			*dev = fd->private_data;
	ssize_t				retval;
	enum ep0_state			state;

	spin_lock_irq (&dev->lock);

	/* report fd mode change before acting on it */
	if (dev->setup_abort) {
		dev->setup_abort = 0;
		retval = -EIDRM;
		goto done;
	}

	/* control DATA stage */
	if ((state = dev->state) == STATE_SETUP) {

		if (dev->setup_in) {		/* stall IN */
			VDEBUG(dev, "ep0in stall\n");
			(void) usb_ep_set_halt (dev->gadget->ep0);
			retval = -EL2HLT;
			dev->state = STATE_CONNECTED;

		} else if (len == 0) {		/* ack SET_CONFIGURATION etc */
			struct usb_ep		*ep = dev->gadget->ep0;
			struct usb_request	*req = dev->req;

			if ((retval = setup_req (ep, req, 0)) == 0)
				retval = usb_ep_queue (ep, req, GFP_ATOMIC);
			dev->state = STATE_CONNECTED;

		} else {			/* collect OUT data */
			if ((fd->f_flags & O_NONBLOCK) != 0
					&& !dev->setup_out_ready) {
				retval = -EAGAIN;
				goto done;
			}
			spin_unlock_irq (&dev->lock);
			retval = wait_event_interruptible (dev->wait,
					dev->setup_out_ready != 0);

			/* FIXME state could change from under us */
			spin_lock_irq (&dev->lock);
			if (retval)
				goto done;
			if (dev->setup_out_error)
				retval = -EIO;
			else {
				len = min (len, dev->req->actual);
// FIXME don't call this with the spinlock held ...
				if (copy_to_user (buf, &dev->req->buf, len))
					retval = -EFAULT;
				clean_req (dev->gadget->ep0, dev->req);
				/* NOTE userspace can't yet choose to stall */
			}
		}
		goto done;
	}

	/* else normal: return event data */
	if (len < sizeof dev->event [0]) {
		retval = -EINVAL;
		goto done;
	}
	len -= len % sizeof (struct usb_gadgetfs_event);
	dev->usermode_setup = 1;

scan:
	/* return queued events right away */
	if (dev->ev_next != 0) {
		unsigned		i, n;
		int			tmp = dev->ev_next;

		len = min (len, tmp * sizeof (struct usb_gadgetfs_event));
		n = len / sizeof (struct usb_gadgetfs_event);

		/* ep0 can't deliver events when STATE_SETUP */
		for (i = 0; i < n; i++) {
			if (dev->event [i].type == GADGETFS_SETUP) {
				len = n = i + 1;
				len *= sizeof (struct usb_gadgetfs_event);
				n = 0;
				break;
			}
		}
		spin_unlock_irq (&dev->lock);
		if (copy_to_user (buf, &dev->event, len))
			retval = -EFAULT;
		else
			retval = len;
		if (len > 0) {
			len /= sizeof (struct usb_gadgetfs_event);

			/* NOTE this doesn't guard against broken drivers;
			 * concurrent ep0 readers may lose events.
			 */
			spin_lock_irq (&dev->lock);
			dev->ev_next -= len;
			if (dev->ev_next != 0)
				memmove (&dev->event, &dev->event [len],
					sizeof (struct usb_gadgetfs_event)
						* (tmp - len));
			if (n == 0)
				dev->state = STATE_SETUP;
			spin_unlock_irq (&dev->lock);
		}
		return retval;
	}
	if (fd->f_flags & O_NONBLOCK) {
		retval = -EAGAIN;
		goto done;
	}

	switch (state) {
	default:
		DBG (dev, "fail %s, state %d\n", __FUNCTION__, state);
		retval = -ESRCH;
		break;
	case STATE_UNCONNECTED:
	case STATE_CONNECTED:
		spin_unlock_irq (&dev->lock);
		DBG (dev, "%s wait\n", __FUNCTION__);

		/* wait for events */
		retval = wait_event_interruptible (dev->wait,
				dev->ev_next != 0);
		if (retval < 0)
			return retval;
		spin_lock_irq (&dev->lock);
		goto scan;
	}

done:
	spin_unlock_irq (&dev->lock);
	return retval;
}

static struct usb_gadgetfs_event *
next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
{
	struct usb_gadgetfs_event	*event;
	unsigned			i;

	switch (type) {
	/* these events purge the queue */
	case GADGETFS_DISCONNECT:
		if (dev->state == STATE_SETUP)
			dev->setup_abort = 1;
		// FALL THROUGH
	case GADGETFS_CONNECT:
		dev->ev_next = 0;
		break;
	case GADGETFS_SETUP:		/* previous request timed out */
	case GADGETFS_SUSPEND:		/* same effect */
		/* these events can't be repeated */
		for (i = 0; i != dev->ev_next; i++) {
			if (dev->event [i].type != type)
				continue;
			DBG (dev, "discard old event %d\n", type);
			dev->ev_next--;
			if (i == dev->ev_next)
				break;
			/* indices start at zero, for simplicity */
			memmove (&dev->event [i], &dev->event [i + 1],
				sizeof (struct usb_gadgetfs_event)
					* (dev->ev_next - i));
		}
		break;
	default:
		BUG ();
	}
	event = &dev->event [dev->ev_next++];
	BUG_ON (dev->ev_next > N_EVENT);
	VDEBUG (dev, "ev %d, next %d\n", type, dev->ev_next);
	memset (event, 0, sizeof *event);
	event->type = type;
	return event;
}

static ssize_t
ep0_write (struct file *fd, const char *buf, size_t len, loff_t *ptr)
{
	struct dev_data		*dev = fd->private_data;
	ssize_t			retval = -ESRCH;

	spin_lock_irq (&dev->lock);

	/* report fd mode change before acting on it */
	if (dev->setup_abort) {
		dev->setup_abort = 0;
		retval = -EIDRM;

	/* data and/or status stage for control request */
	} else if (dev->state == STATE_SETUP) {

		/* IN DATA+STATUS caller makes len <= wLength */
		if (dev->setup_in) {
			retval = setup_req (dev->gadget->ep0, dev->req, len);
			if (retval == 0) {
				spin_unlock_irq (&dev->lock);
				if (copy_from_user (dev->req->buf, buf, len))
					retval = -EFAULT;
				else
					retval = usb_ep_queue (
						dev->gadget->ep0, dev->req,
						GFP_KERNEL);
				if (retval < 0) {
					spin_lock_irq (&dev->lock);
					clean_req (dev->gadget->ep0, dev->req);
					spin_unlock_irq (&dev->lock);
				} else
					retval = len;

				return retval;
			}

		/* can stall some OUT transfers */
		} else if (dev->setup_can_stall) {
			VDEBUG(dev, "ep0out stall\n");
			(void) usb_ep_set_halt (dev->gadget->ep0);
			retval = -EL2HLT;
			dev->state = STATE_CONNECTED;
		} else {
			DBG(dev, "bogus ep0out stall!\n");
		}
	} else
		DBG (dev, "fail %s, state %d\n", __FUNCTION__, dev->state);

	spin_unlock_irq (&dev->lock);
	return retval;
}

static int
ep0_fasync (int f, struct file *fd, int on)
{
	struct dev_data		*dev = fd->private_data;
	// caller must F_SETOWN before signal delivery happens
	VDEBUG (dev, "%s %s\n", __FUNCTION__, on ? "on" : "off");
	return fasync_helper (f, fd, on, &dev->fasync);
}

static struct usb_gadget_driver gadgetfs_driver;

static int
dev_release (struct inode *inode, struct file *fd)
{
	struct dev_data		*dev = fd->private_data;

	/* closing ep0 === shutdown all */

	usb_gadget_unregister_driver (&gadgetfs_driver);

	/* at this point "good" hardware has disconnected the
	 * device from USB; the host won't see it any more.
	 * alternatively, all host requests will time out.
	 */

	fasync_helper (-1, fd, 0, &dev->fasync);
	kfree (dev->buf);
	dev->buf = 0;
	put_dev (dev);

	/* other endpoints were all decoupled from this device */
	dev->state = STATE_DEV_DISABLED;
	return 0;
}

static int dev_ioctl (struct inode *inode, struct file *fd,
		unsigned code, unsigned long value)
{
	struct dev_data		*dev = fd->private_data;
	struct usb_gadget	*gadget = dev->gadget;

	if (gadget->ops->ioctl)
		return gadget->ops->ioctl (gadget, code, value);
	return -ENOTTY;
}

/* used after device configuration */
static struct file_operations ep0_io_operations = {
	.owner =	THIS_MODULE,
	.read =		ep0_read,
	.write =	ep0_write,
	.fasync =	ep0_fasync,
	// .poll =	ep0_poll,
	.ioctl =	dev_ioctl,
	.release =	dev_release,
};

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

/* The in-kernel gadget driver handles most ep0 issues, in particular
 * enumerating the single configuration (as provided from user space).
 *
 * Unrecognized ep0 requests may be handled in user space.
 */

#ifdef	HIGHSPEED
static void make_qualifier (struct dev_data *dev)
{
	struct usb_qualifier_descriptor		qual;
	struct usb_device_descriptor		*desc;

	qual.bLength = sizeof qual;
	qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
	qual.bcdUSB = __constant_cpu_to_le16 (0x0200);

	desc = dev->dev;
	qual.bDeviceClass = desc->bDeviceClass;
	qual.bDeviceSubClass = desc->bDeviceSubClass;
	qual.bDeviceProtocol = desc->bDeviceProtocol;

	/* assumes ep0 uses the same value for both speeds ... */
	qual.bMaxPacketSize0 = desc->bMaxPacketSize0;

	qual.bNumConfigurations = 1;
	qual.bRESERVED = 0;

	memcpy (dev->rbuf, &qual, sizeof qual);
}
#endif

static int
config_buf (struct dev_data *dev, u8 type, unsigned index)
{
	int		len;
#ifdef HIGHSPEED
	int		hs;
#endif

	/* only one configuration */
	if (index > 0)
		return -EINVAL;

#ifdef HIGHSPEED
	hs = (dev->gadget->speed == USB_SPEED_HIGH);
	if (type == USB_DT_OTHER_SPEED_CONFIG)
		hs = !hs;
	if (hs) {
		dev->req->buf = dev->hs_config;
		len = le16_to_cpup (&dev->hs_config->wTotalLength);
	} else
#endif
	{
		dev->req->buf = dev->config;
		len = le16_to_cpup (&dev->config->wTotalLength);
	}
	((u8 *)dev->req->buf) [1] = type;
	return len;
}

static int
gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
{
	struct dev_data			*dev = get_gadget_data (gadget);
	struct usb_request		*req = dev->req;
	int				value = -EOPNOTSUPP;
	struct usb_gadgetfs_event	*event;

	spin_lock (&dev->lock);
	dev->setup_abort = 0;
	if (dev->state == STATE_UNCONNECTED) {
		struct usb_ep	*ep;
		struct ep_data	*data;

		dev->state = STATE_CONNECTED;
		dev->dev->bMaxPacketSize0 = gadget->ep0->maxpacket;

#ifdef	HIGHSPEED
		if (gadget->speed == USB_SPEED_HIGH && dev->hs_config == 0) {
			ERROR (dev, "no high speed config??\n");
			return -EINVAL;
		}
#endif	/* HIGHSPEED */

		INFO (dev, "connected\n");
		event = next_event (dev, GADGETFS_CONNECT);
		event->u.speed = gadget->speed;
		ep0_readable (dev);

		list_for_each_entry (ep, &gadget->ep_list, ep_list) {
			data = ep->driver_data;
			/* ... down_trylock (&data->lock) ... */
			if (data->state != STATE_EP_DEFER_ENABLE)
				continue;
#ifdef	HIGHSPEED
			if (gadget->speed == USB_SPEED_HIGH)
				value = usb_ep_enable (ep, &data->hs_desc);
			else
#endif	/* HIGHSPEED */
				value = usb_ep_enable (ep, &data->desc);
			if (value) {
				ERROR (dev, "deferred %s enable --> %d\n",
					data->name, value);
				continue;
			}
			data->state = STATE_EP_ENABLED;
			wake_up (&data->wait);
			DBG (dev, "woke up %s waiters\n", data->name);
		}

	/* host may have given up waiting for response.  we can miss control
	 * requests handled lower down (device/endpoint status and features);
	 * then ep0_{read,write} will report the wrong status. controller
	 * driver will have aborted pending i/o.
	 */
	} else if (dev->state == STATE_SETUP)
		dev->setup_abort = 1;

	req->buf = dev->rbuf;
	req->dma = DMA_ADDR_INVALID;
	req->context = 0;
	value = -EOPNOTSUPP;
	switch (ctrl->bRequest) {

	case USB_REQ_GET_DESCRIPTOR:
		if (ctrl->bRequestType != USB_DIR_IN)
			goto unrecognized;
		switch (ctrl->wValue >> 8) {

		case USB_DT_DEVICE: