usb: raw-gadget: support stalling/halting/wedging endpoints

Raw Gadget is currently unable to stall/halt/wedge gadget endpoints,
which is required for proper emulation of certain USB classes.

This patch adds a few more ioctls:

- USB_RAW_IOCTL_EP0_STALL allows to stall control endpoint #0 when
  there's a pending setup request for it.
- USB_RAW_IOCTL_SET/CLEAR_HALT/WEDGE allow to set/clear halt/wedge status
  on non-control non-isochronous endpoints.

Fixes: f2c2e71764 ("usb: gadget: add raw-gadget interface")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Documentation/usb/raw-gadget.rst

@@ -52,8 +52,6 @@ The typical usage of Raw Gadget looks like:
 Potential future improvements
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-- Implement ioctl's for setting/clearing halt status on endpoints.
-
 - Reporting more events (suspend, resume, etc.) through
   USB_RAW_IOCTL_EVENT_FETCH.
 

drivers/usb/gadget/legacy/raw_gadget.c

@@ -204,7 +204,7 @@ static void dev_free(struct kref *kref)
 	}
 	raw_event_queue_destroy(&dev->queue);
 	for (i = 0; i < dev->eps_num; i++) {
-		if (dev->eps[i].state != STATE_EP_ENABLED)
+		if (dev->eps[i].state == STATE_EP_DISABLED)
 			continue;
 		usb_ep_disable(dev->eps[i].ep);
 		usb_ep_free_request(dev->eps[i].ep, dev->eps[i].req);
@@ -704,6 +704,50 @@ free:
 	return ret;
 }
 
+static int raw_ioctl_ep0_stall(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	if (value)
+		return -EINVAL;
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (dev->ep0_urb_queued) {
+		dev_dbg(&dev->gadget->dev, "fail, urb already queued\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (!dev->ep0_in_pending && !dev->ep0_out_pending) {
+		dev_dbg(&dev->gadget->dev, "fail, no request pending\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	ret = usb_ep_set_halt(dev->gadget->ep0);
+	if (ret < 0)
+		dev_err(&dev->gadget->dev,
+				"fail, usb_ep_set_halt returned %d\n", ret);
+
+	if (dev->ep0_in_pending)
+		dev->ep0_in_pending = false;
+	else
+		dev->ep0_out_pending = false;
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
 static int raw_ioctl_ep_enable(struct raw_dev *dev, unsigned long value)
 {
 	int ret = 0, i;
@@ -798,7 +842,7 @@ static int raw_ioctl_ep_disable(struct raw_dev *dev, unsigned long value)
 		ret = -EBUSY;
 		goto out_unlock;
 	}
-	if (dev->eps[i].state != STATE_EP_ENABLED) {
+	if (dev->eps[i].state == STATE_EP_DISABLED) {
 		dev_dbg(&dev->gadget->dev, "fail, endpoint is not enabled\n");
 		ret = -EINVAL;
 		goto out_unlock;
@@ -832,6 +876,74 @@ out_unlock:
 	return ret;
 }
 
+static int raw_ioctl_ep_set_clear_halt_wedge(struct raw_dev *dev,
+		unsigned long value, bool set, bool halt)
+{
+	int ret = 0, i = value;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (i < 0 || i >= dev->eps_num) {
+		dev_dbg(dev->dev, "fail, invalid endpoint\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (dev->eps[i].state == STATE_EP_DISABLED) {
+		dev_dbg(&dev->gadget->dev, "fail, endpoint is not enabled\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (dev->eps[i].disabling) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, disable is in progress\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (dev->eps[i].urb_queued) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, waiting for urb completion\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (usb_endpoint_xfer_isoc(dev->eps[i].ep->desc)) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, can't halt/wedge ISO endpoint\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (set && halt) {
+		ret = usb_ep_set_halt(dev->eps[i].ep);
+		if (ret < 0)
+			dev_err(&dev->gadget->dev,
+				"fail, usb_ep_set_halt returned %d\n", ret);
+	} else if (!set && halt) {
+		ret = usb_ep_clear_halt(dev->eps[i].ep);
+		if (ret < 0)
+			dev_err(&dev->gadget->dev,
+				"fail, usb_ep_clear_halt returned %d\n", ret);
+	} else if (set && !halt) {
+		ret = usb_ep_set_wedge(dev->eps[i].ep);
+		if (ret < 0)
+			dev_err(&dev->gadget->dev,
+				"fail, usb_ep_set_wedge returned %d\n", ret);
+	}
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
 static void gadget_ep_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct raw_ep *r_ep = (struct raw_ep *)ep->driver_data;
@@ -1128,6 +1240,21 @@ static long raw_ioctl(struct file *fd, unsigned int cmd, unsigned long value)
 	case USB_RAW_IOCTL_EPS_INFO:
 		ret = raw_ioctl_eps_info(dev, value);
 		break;
+	case USB_RAW_IOCTL_EP0_STALL:
+		ret = raw_ioctl_ep0_stall(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP_SET_HALT:
+		ret = raw_ioctl_ep_set_clear_halt_wedge(
+					dev, value, true, true);
+		break;
+	case USB_RAW_IOCTL_EP_CLEAR_HALT:
+		ret = raw_ioctl_ep_set_clear_halt_wedge(
+					dev, value, false, true);
+		break;
+	case USB_RAW_IOCTL_EP_SET_WEDGE:
+		ret = raw_ioctl_ep_set_clear_halt_wedge(
+					dev, value, true, false);
+		break;
 	default:
 		ret = -EINVAL;
 	}

include/uapi/linux/usb/raw_gadget.h

@@ -231,4 +231,19 @@ struct usb_raw_eps_info {
  */
 #define USB_RAW_IOCTL_EPS_INFO		_IOR('U', 11, struct usb_raw_eps_info)
 
+/*
+ * Stalls a pending control request on endpoint 0.
+ * Returns 0 on success or negative error code on failure.
+ */
+#define USB_RAW_IOCTL_EP0_STALL		_IO('U', 12)
+
+/*
+ * Sets or clears halt or wedge status of the endpoint.
+ * Accepts endpoint handle as an argument.
+ * Returns 0 on success or negative error code on failure.
+ */
+#define USB_RAW_IOCTL_EP_SET_HALT	_IOW('U', 13, __u32)
+#define USB_RAW_IOCTL_EP_CLEAR_HALT	_IOW('U', 14, __u32)
+#define USB_RAW_IOCTL_EP_SET_WEDGE	_IOW('U', 15, __u32)
+
 #endif /* _UAPI__LINUX_USB_RAW_GADGET_H */