inode.c

linux下面gadget设备驱动

	if (likely(epdata && epdata->ep && priv->req))
		value = usb_ep_dequeue (epdata->ep, priv->req);
	else
		value = -EINVAL;
	// spin_unlock(&epdata->dev->lock);
	local_irq_enable();

	aio_put_req(iocb);
	return value;
}

static ssize_t ep_aio_read_retry(struct kiocb *iocb)
{
	struct kiocb_priv	*priv = iocb->private;
	ssize_t			len, total;
	void			*to_copy;
	int			i;

	/* we "retry" to get the right mm context for this: */

	/* copy stuff into user buffers */
	total = priv->actual;
	len = 0;
	to_copy = priv->buf;
	for (i=0; i < priv->nr_segs; i++) {
		ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);

		if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
			if (len == 0)
				len = -EFAULT;
			break;
		}

		total -= this;
		len += this;
		to_copy += this;
		if (total == 0)
			break;
	}
	kfree(priv->buf);
	kfree(priv);
	return len;
}

static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct kiocb		*iocb = req->context;
	struct kiocb_priv	*priv = iocb->private;
	struct ep_data		*epdata = priv->epdata;

	/* lock against disconnect (and ideally, cancel) */
	spin_lock(&epdata->dev->lock);
	priv->req = NULL;
	priv->epdata = NULL;

	/* if this was a write or a read returning no data then we
	 * don't need to copy anything to userspace, so we can
	 * complete the aio request immediately.
	 */
	if (priv->iv == NULL || unlikely(req->actual == 0)) {
		kfree(req->buf);
		kfree(priv);
		iocb->private = NULL;
		/* aio_complete() reports bytes-transferred _and_ faults */
		aio_complete(iocb, req->actual ? req->actual : req->status,
				req->status);
	} else {
		/* retry() won't report both; so we hide some faults */
		if (unlikely(0 != req->status))
			DBG(epdata->dev, "%s fault %d len %d\n",
				ep->name, req->status, req->actual);

		priv->buf = req->buf;
		priv->actual = req->actual;
		kick_iocb(iocb);
	}
	spin_unlock(&epdata->dev->lock);

	usb_ep_free_request(ep, req);
	put_ep(epdata);
}

static ssize_t
ep_aio_rwtail(
	struct kiocb	*iocb,
	char		*buf,
	size_t		len,
	struct ep_data	*epdata,
	const struct iovec *iv,
	unsigned long	nr_segs
)
{
	struct kiocb_priv	*priv;
	struct usb_request	*req;
	ssize_t			value;

	priv = kmalloc(sizeof *priv, GFP_KERNEL);
	if (!priv) {
		value = -ENOMEM;
fail:
		kfree(buf);
		return value;
	}
	iocb->private = priv;
	priv->iv = iv;
	priv->nr_segs = nr_segs;

	value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
	if (unlikely(value < 0)) {
		kfree(priv);
		goto fail;
	}

	iocb->ki_cancel = ep_aio_cancel;
	get_ep(epdata);
	priv->epdata = epdata;
	priv->actual = 0;

	/* each kiocb is coupled to one usb_request, but we can't
	 * allocate or submit those if the host disconnected.
	 */
	spin_lock_irq(&epdata->dev->lock);
	if (likely(epdata->ep)) {
		req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
		if (likely(req)) {
			priv->req = req;
			req->buf = buf;
			req->length = len;
			req->complete = ep_aio_complete;
			req->context = iocb;
			value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
			if (unlikely(0 != value))
				usb_ep_free_request(epdata->ep, req);
		} else
			value = -EAGAIN;
	} else
		value = -ENODEV;
	spin_unlock_irq(&epdata->dev->lock);

	up(&epdata->lock);

	if (unlikely(value)) {
		kfree(priv);
		put_ep(epdata);
	} else
		value = (iv ? -EIOCBRETRY : -EIOCBQUEUED);
	return value;
}

static ssize_t
ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
		unsigned long nr_segs, loff_t o)
{
	struct ep_data		*epdata = iocb->ki_filp->private_data;
	char			*buf;

	if (unlikely(epdata->desc.bEndpointAddress & USB_DIR_IN))
		return -EINVAL;

	buf = kmalloc(iocb->ki_left, GFP_KERNEL);
	if (unlikely(!buf))
		return -ENOMEM;

	iocb->ki_retry = ep_aio_read_retry;
	return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
}

static ssize_t
ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
		unsigned long nr_segs, loff_t o)
{
	struct ep_data		*epdata = iocb->ki_filp->private_data;
	char			*buf;
	size_t			len = 0;
	int			i = 0;

	if (unlikely(!(epdata->desc.bEndpointAddress & USB_DIR_IN)))
		return -EINVAL;

	buf = kmalloc(iocb->ki_left, GFP_KERNEL);
	if (unlikely(!buf))
		return -ENOMEM;

	for (i=0; i < nr_segs; i++) {
		if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
				iov[i].iov_len) != 0)) {
			kfree(buf);
			return -EFAULT;
		}
		len += iov[i].iov_len;
	}
	return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
}

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

/* used after endpoint configuration */
static const struct file_operations ep_io_operations = {
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,

	.read =		ep_read,
	.write =	ep_write,
	.ioctl =	ep_ioctl,
	.release =	ep_release,

	.aio_read =	ep_aio_read,
	.aio_write =	ep_aio_write,
};

/* ENDPOINT INITIALIZATION
 *
 *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 *     status = write (fd, descriptors, sizeof descriptors)
 *
 * That write establishes the endpoint configuration, configuring
 * the controller to process bulk, interrupt, or isochronous transfers
 * at the right maxpacket size, and so on.
 *
 * The descriptors are message type 1, identified by a host order u32
 * at the beginning of what's written.  Descriptor order is: full/low
 * speed descriptor, then optional high speed descriptor.
 */
static ssize_t
ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
{
	struct ep_data		*data = fd->private_data;
	struct usb_ep		*ep;
	u32			tag;
	int			value, length = len;

	if ((value = down_interruptible (&data->lock)) < 0)
		return value;

	if (data->state != STATE_EP_READY) {
		value = -EL2HLT;
		goto fail;
	}

	value = len;
	if (len < USB_DT_ENDPOINT_SIZE + 4)
		goto fail0;

	/* we might need to change message format someday */
	if (copy_from_user (&tag, buf, 4)) {
		goto fail1;
	}
	if (tag != 1) {
		DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
		goto fail0;
	}
	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;
		}
	}

	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	CONFIG_USB_GADGET_DUALSPEED
	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 abandoned\n",
				data->name);
		value = -EINVAL;
	}
	if (value == 0) {
		fd->f_op = &ep_io_operations;
		value = length;
	}
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->i_private;
	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 const struct file_operations ep_config_operations = {
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,

	.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) {
		kfree(req->buf);
		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;
	unsigned long		flags;
	int			free = 1;

	/* for control OUT, data must still get to userspace */
	spin_lock_irqsave(&dev->lock, flags);
	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);
	}

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

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 = kmalloc(len, GFP_ATOMIC);
	if (req->buf == NULL) {
		req->buf = dev->rbuf;
		return -ENOMEM;
	}
	req->complete = ep0_complete;
	req->length = len;
	req->zero = 0;
	return 0;
}

static ssize_t
ep0_read (struct file *fd, char __user *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_DEV_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_DEV_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_DEV_CONNECTED;

			/* assume that was SET_CONFIGURATION */
			if (dev->current_config) {
				unsigned power;

				if (gadget_is_dualspeed(dev->gadget)
						&& (dev->gadget->speed
							== USB_SPEED_HIGH))
					power = dev->hs_config->bMaxPower;
				else
					power = dev->config->bMaxPower;
				usb_gadget_vbus_draw(dev->gadget, 2 * power);
			}

		} 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->state != STATE_DEV_SETUP) {
				retval = -ECANCELED;
				goto done;
			}
			dev->state = STATE_DEV_CONNECTED;

			if (dev->setup_out_error)
				retval = -EIO;
			else {
				len = min (len, (size_t)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;

		n = len / sizeof (struct usb_gadgetfs_event);
		if (dev->ev_next < n)
			n = dev->ev_next;

		/* ep0 i/o has special semantics during STATE_DEV_SETUP */
		for (i = 0; i < n; i++) {
			if (dev->event [i].type == GADGETFS_SETUP) {
				dev->state = STATE_DEV_SETUP;
				n = i + 1;