USB: xhci: Bandwidth allocation support

Since the xHCI host controller hardware (xHC) has an internal schedule, it
needs a better representation of what devices are consuming bandwidth on
the bus.  Each device is represented by a device context, with data about
the device, endpoints, and pointers to each endpoint ring.

We need to update the endpoint information for a device context before a
new configuration or alternate interface setting is selected.  We setup an
input device context with modified endpoint information and newly
allocated endpoint rings, and then submit a Configure Endpoint Command to
the hardware.

The host controller can reject the new configuration if it exceeds the bus
bandwidth, or the host controller doesn't have enough internal resources
for the configuration.  If the command fails, we still have the older
device context with the previous configuration.  If the command succeeds,
we free the old endpoint rings.

The root hub isn't a real device, so always say yes to any bandwidth
changes for it.

The USB core will enable, disable, and then enable endpoint 0 several
times during the initialization sequence.  The device will always have an
endpoint ring for endpoint 0 and bandwidth allocated for that, unless the
device is disconnected or gets a SetAddress 0 request.  So we don't pay
attention for when xhci_check_bandwidth() is called for a re-add of
endpoint 0.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 572 insertions, 5 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 5d94b4f..50ab525 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -530,6 +530,26 @@ unsigned int xhci_get_endpoint_index(struct usb_endpoint_descriptor *desc)
 	return index;
 }
 
+/* Find the flag for this endpoint (for use in the control context).  Use the
+ * endpoint index to create a bitmask.  The slot context is bit 0, endpoint 0 is
+ * bit 1, etc.
+ */
+unsigned int xhci_get_endpoint_flag(struct usb_endpoint_descriptor *desc)
+{
+	return 1 << (xhci_get_endpoint_index(desc) + 1);
+}
+
+/* Compute the last valid endpoint context index.  Basically, this is the
+ * endpoint index plus one.  For slot contexts with more than valid endpoint,
+ * we find the most significant bit set in the added contexts flags.
+ * e.g. ep 1 IN (with epnum 0x81) => added_ctxs = 0b1000
+ * fls(0b1000) = 4, but the endpoint context index is 3, so subtract one.
+ */
+static inline unsigned int xhci_last_valid_endpoint(u32 added_ctxs)
+{
+	return fls(added_ctxs) - 1;
+}
+
 /* Returns 1 if the arguments are OK;
  * returns 0 this is a root hub; returns -EINVAL for NULL pointers.
  */
@@ -602,6 +622,349 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 	return -ENOSYS;
 }
 
+/* Drop an endpoint from a new bandwidth configuration for this device.
+ * Only one call to this function is allowed per endpoint before
+ * check_bandwidth() or reset_bandwidth() must be called.
+ * A call to xhci_drop_endpoint() followed by a call to xhci_add_endpoint() will
+ * add the endpoint to the schedule with possibly new parameters denoted by a
+ * different endpoint descriptor in usb_host_endpoint.
+ * A call to xhci_add_endpoint() followed by a call to xhci_drop_endpoint() is
+ * not allowed.
+ */
+int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	unsigned long flags;
+	struct xhci_hcd *xhci;
+	struct xhci_device_control *in_ctx;
+	unsigned int last_ctx;
+	unsigned int ep_index;
+	struct xhci_ep_ctx *ep_ctx;
+	u32 drop_flag;
+	u32 new_add_flags, new_drop_flags, new_slot_info;
+	int ret;
+
+	ret = xhci_check_args(hcd, udev, ep, 1, __func__);
+	xhci_dbg(xhci, "%s called for udev %#x\n", __func__, (unsigned int) udev);
+	if (ret <= 0)
+		return ret;
+	xhci = hcd_to_xhci(hcd);
+
+	drop_flag = xhci_get_endpoint_flag(&ep->desc);
+	if (drop_flag == SLOT_FLAG || drop_flag == EP0_FLAG) {
+		xhci_dbg(xhci, "xHCI %s - can't drop slot or ep 0 %#x\n",
+				__func__, drop_flag);
+		return 0;
+	}
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (!xhci->devs || !xhci->devs[udev->slot_id]) {
+		xhci_warn(xhci, "xHCI %s called with unaddressed device\n",
+				__func__);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return -EINVAL;
+	}
+
+	in_ctx = xhci->devs[udev->slot_id]->in_ctx;
+	ep_index = xhci_get_endpoint_index(&ep->desc);
+	ep_ctx = &xhci->devs[udev->slot_id]->out_ctx->ep[ep_index];
+	/* If the HC already knows the endpoint is disabled,
+	 * or the HCD has noted it is disabled, ignore this request
+	 */
+	if ((ep_ctx->ep_info & EP_STATE_MASK) == EP_STATE_DISABLED ||
+			in_ctx->drop_flags & xhci_get_endpoint_flag(&ep->desc)) {
+		xhci_warn(xhci, "xHCI %s called with disabled ep %#x\n",
+				__func__, (unsigned int) ep);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return 0;
+	}
+
+	in_ctx->drop_flags |= drop_flag;
+	new_drop_flags = in_ctx->drop_flags;
+
+	in_ctx->add_flags = ~drop_flag;
+	new_add_flags = in_ctx->add_flags;
+
+	last_ctx = xhci_last_valid_endpoint(in_ctx->add_flags);
+	/* Update the last valid endpoint context, if we deleted the last one */
+	if ((in_ctx->slot.dev_info & LAST_CTX_MASK) > LAST_CTX(last_ctx)) {
+		in_ctx->slot.dev_info &= ~LAST_CTX_MASK;
+		in_ctx->slot.dev_info |= LAST_CTX(last_ctx);
+	}
+	new_slot_info = in_ctx->slot.dev_info;
+
+	xhci_endpoint_zero(xhci, xhci->devs[udev->slot_id], ep);
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	xhci_dbg(xhci, "drop ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x, new slot info = %#x\n",
+			(unsigned int) ep->desc.bEndpointAddress,
+			udev->slot_id,
+			(unsigned int) new_drop_flags,
+			(unsigned int) new_add_flags,
+			(unsigned int) new_slot_info);
+	return 0;
+}
+
+/* Add an endpoint to a new possible bandwidth configuration for this device.
+ * Only one call to this function is allowed per endpoint before
+ * check_bandwidth() or reset_bandwidth() must be called.
+ * A call to xhci_drop_endpoint() followed by a call to xhci_add_endpoint() will
+ * add the endpoint to the schedule with possibly new parameters denoted by a
+ * different endpoint descriptor in usb_host_endpoint.
+ * A call to xhci_add_endpoint() followed by a call to xhci_drop_endpoint() is
+ * not allowed.
+ */
+int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	unsigned long flags;
+	struct xhci_hcd *xhci;
+	struct xhci_device_control *in_ctx;
+	unsigned int ep_index;
+	struct xhci_ep_ctx *ep_ctx;
+	u32 added_ctxs;
+	unsigned int last_ctx;
+	u32 new_add_flags, new_drop_flags, new_slot_info;
+	int ret = 0;
+
+	ret = xhci_check_args(hcd, udev, ep, 1, __func__);
+	if (ret <= 0)
+		return ret;
+	xhci = hcd_to_xhci(hcd);
+
+	added_ctxs = xhci_get_endpoint_flag(&ep->desc);
+	last_ctx = xhci_last_valid_endpoint(added_ctxs);
+	if (added_ctxs == SLOT_FLAG || added_ctxs == EP0_FLAG) {
+		/* FIXME when we have to issue an evaluate endpoint command to
+		 * deal with ep0 max packet size changing once we get the
+		 * descriptors
+		 */
+		xhci_dbg(xhci, "xHCI %s - can't add slot or ep 0 %#x\n",
+				__func__, added_ctxs);
+		return 0;
+	}
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (!xhci->devs || !xhci->devs[udev->slot_id]) {
+		xhci_warn(xhci, "xHCI %s called with unaddressed device\n",
+				__func__);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return -EINVAL;
+	}
+
+	in_ctx = xhci->devs[udev->slot_id]->in_ctx;
+	ep_index = xhci_get_endpoint_index(&ep->desc);
+	ep_ctx = &xhci->devs[udev->slot_id]->out_ctx->ep[ep_index];
+	/* If the HCD has already noted the endpoint is enabled,
+	 * ignore this request.
+	 */
+	if (in_ctx->add_flags & xhci_get_endpoint_flag(&ep->desc)) {
+		xhci_warn(xhci, "xHCI %s called with enabled ep %#x\n",
+				__func__, (unsigned int) ep);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return 0;
+	}
+
+	if (xhci_endpoint_init(xhci, xhci->devs[udev->slot_id], udev, ep) < 0) {
+		dev_dbg(&udev->dev, "%s - could not initialize ep %#x\n",
+				__func__, ep->desc.bEndpointAddress);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return -ENOMEM;
+	}
+
+	in_ctx->add_flags |= added_ctxs;
+	new_add_flags = in_ctx->add_flags;
+
+	/* If xhci_endpoint_disable() was called for this endpoint, but the
+	 * xHC hasn't been notified yet through the check_bandwidth() call,
+	 * this re-adds a new state for the endpoint from the new endpoint
+	 * descriptors.  We must drop and re-add this endpoint, so we leave the
+	 * drop flags alone.
+	 */
+	new_drop_flags = in_ctx->drop_flags;
+
+	/* Update the last valid endpoint context, if we just added one past */
+	if ((in_ctx->slot.dev_info & LAST_CTX_MASK) < LAST_CTX(last_ctx)) {
+		in_ctx->slot.dev_info &= ~LAST_CTX_MASK;
+		in_ctx->slot.dev_info |= LAST_CTX(last_ctx);
+	}
+	new_slot_info = in_ctx->slot.dev_info;
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x, new slot info = %#x\n",
+			(unsigned int) ep->desc.bEndpointAddress,
+			udev->slot_id,
+			(unsigned int) new_drop_flags,
+			(unsigned int) new_add_flags,
+			(unsigned int) new_slot_info);
+	return 0;
+}
+
+static void xhci_zero_in_ctx(struct xhci_virt_device *virt_dev)
+{
+	struct xhci_ep_ctx *ep_ctx;
+	int i;
+
+	/* When a device's add flag and drop flag are zero, any subsequent
+	 * configure endpoint command will leave that endpoint's state
+	 * untouched.  Make sure we don't leave any old state in the input
+	 * endpoint contexts.
+	 */
+	virt_dev->in_ctx->drop_flags = 0;
+	virt_dev->in_ctx->add_flags = 0;
+	virt_dev->in_ctx->slot.dev_info &= ~LAST_CTX_MASK;
+	/* Endpoint 0 is always valid */
+	virt_dev->in_ctx->slot.dev_info |= LAST_CTX(1);
+	for (i = 1; i < 31; ++i) {
+		ep_ctx = &virt_dev->in_ctx->ep[i];
+		ep_ctx->ep_info = 0;
+		ep_ctx->ep_info2 = 0;
+		ep_ctx->deq[0] = 0;
+		ep_ctx->deq[1] = 0;
+		ep_ctx->tx_info = 0;
+	}
+}
+
+int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	int i;
+	int ret = 0;
+	int timeleft;
+	unsigned long flags;
+	struct xhci_hcd *xhci;
+	struct xhci_virt_device	*virt_dev;
+
+	ret = xhci_check_args(hcd, udev, NULL, 0, __func__);
+	if (ret <= 0)
+		return ret;
+	xhci = hcd_to_xhci(hcd);
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (!udev->slot_id || !xhci->devs || !xhci->devs[udev->slot_id]) {
+		xhci_warn(xhci, "xHCI %s called with unaddressed device\n",
+				__func__);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return -EINVAL;
+	}
+	xhci_dbg(xhci, "%s called for udev %#x\n", __func__, (unsigned int) udev);
+	virt_dev = xhci->devs[udev->slot_id];
+
+	/* See section 4.6.6 - A0 = 1; A1 = D0 = D1 = 0 */
+	virt_dev->in_ctx->add_flags |= SLOT_FLAG;
+	virt_dev->in_ctx->add_flags &= ~EP0_FLAG;
+	virt_dev->in_ctx->drop_flags &= ~SLOT_FLAG;
+	virt_dev->in_ctx->drop_flags &= ~EP0_FLAG;
+	xhci_dbg(xhci, "New Input Control Context:\n");
+	xhci_dbg_ctx(xhci, virt_dev->in_ctx, virt_dev->in_ctx_dma,
+			LAST_CTX_TO_EP_NUM(virt_dev->in_ctx->slot.dev_info));
+
+	ret = queue_configure_endpoint(xhci, virt_dev->in_ctx_dma, udev->slot_id);
+	if (ret < 0) {
+		xhci_dbg(xhci, "FIXME allocate a new ring segment\n");
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return -ENOMEM;
+	}
+	ring_cmd_db(xhci);
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	/* Wait for the configure endpoint command to complete */
+	timeleft = wait_for_completion_interruptible_timeout(
+			&virt_dev->cmd_completion,
+			USB_CTRL_SET_TIMEOUT);
+	if (timeleft <= 0) {
+		xhci_warn(xhci, "%s while waiting for configure endpoint command\n",
+				timeleft == 0 ? "Timeout" : "Signal");
+		/* FIXME cancel the configure endpoint command */
+		return -ETIME;
+	}
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	switch (virt_dev->cmd_status) {
+	case COMP_ENOMEM:
+		dev_warn(&udev->dev, "Not enough host controller resources "
+				"for new device state.\n");
+		ret = -ENOMEM;
+		/* FIXME: can we allocate more resources for the HC? */
+		break;
+	case COMP_BW_ERR:
+		dev_warn(&udev->dev, "Not enough bandwidth "
+				"for new device state.\n");
+		ret = -ENOSPC;
+		/* FIXME: can we go back to the old state? */
+		break;
+	case COMP_TRB_ERR:
+		/* the HCD set up something wrong */
+		dev_warn(&udev->dev, "ERROR: Endpoint drop flag = 0, add flag = 1, "
+				"and endpoint is not disabled.\n");
+		ret = -EINVAL;
+		break;
+	case COMP_SUCCESS:
+		dev_dbg(&udev->dev, "Successful Endpoint Configure command\n");
+		break;
+	default:
+		xhci_err(xhci, "ERROR: unexpected command completion "
+				"code 0x%x.\n", virt_dev->cmd_status);
+		ret = -EINVAL;
+		break;
+	}
+	if (ret) {
+		/* Callee should call reset_bandwidth() */
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return ret;
+	}
+
+	xhci_dbg(xhci, "Output context after successful config ep cmd:\n");
+	xhci_dbg_ctx(xhci, virt_dev->out_ctx, virt_dev->out_ctx_dma,
+			LAST_CTX_TO_EP_NUM(virt_dev->in_ctx->slot.dev_info));
+
+	xhci_zero_in_ctx(virt_dev);
+	/* Free any old rings */
+	for (i = 1; i < 31; ++i) {
+		if (virt_dev->new_ep_rings[i]) {
+			xhci_ring_free(xhci, virt_dev->ep_rings[i]);
+			virt_dev->ep_rings[i] = virt_dev->new_ep_rings[i];
+			virt_dev->new_ep_rings[i] = NULL;
+		}
+	}
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	return ret;
+}
+
+void xhci_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	unsigned long flags;
+	struct xhci_hcd *xhci;
+	struct xhci_virt_device	*virt_dev;
+	int i, ret;
+
+	ret = xhci_check_args(hcd, udev, NULL, 0, __func__);
+	if (ret <= 0)
+		return;
+	xhci = hcd_to_xhci(hcd);
+
+	spin_lock_irqsave(&xhci->lock, flags);
+	if (!xhci->devs || !xhci->devs[udev->slot_id]) {
+		xhci_warn(xhci, "xHCI %s called with unaddressed device\n",
+				__func__);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		return;
+	}
+	xhci_dbg(xhci, "%s called for udev %#x\n", __func__, (unsigned int) udev);
+	virt_dev = xhci->devs[udev->slot_id];
+	/* Free any rings allocated for added endpoints */
+	for (i = 0; i < 31; ++i) {
+		if (virt_dev->new_ep_rings[i]) {
+			xhci_ring_free(xhci, virt_dev->new_ep_rings[i]);
+			virt_dev->new_ep_rings[i] = NULL;
+		}
+	}
+	xhci_zero_in_ctx(virt_dev);
+	spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
 /*
  * At this point, the struct usb_device is about to go away, the device has
  * disconnected, and all traffic has been stopped and the endpoints have been
@@ -783,7 +1146,12 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
 	 * address given back to us by the HC.
 	 */
 	udev->devnum = (virt_dev->out_ctx->slot.dev_state & DEV_ADDR_MASK) + 1;
-	/* FIXME: Zero the input context control for later use? */
+	/* Zero the input context control for later use */
+	virt_dev->in_ctx->add_flags = 0;
+	virt_dev->in_ctx->drop_flags = 0;
+	/* Mirror flags in the output context for future ep enable/disable */
+	virt_dev->out_ctx->add_flags = SLOT_FLAG | EP0_FLAG;
+	virt_dev->out_ctx->drop_flags = 0;
 	spin_unlock_irqrestore(&xhci->lock, flags);
 
 	xhci_dbg(xhci, "Device address = %d\n", udev->devnum);
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 6ff2e29..8cd55f0 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -103,7 +103,7 @@ static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
 }
 
 /* XXX: Do we need the hcd structure in all these functions? */
-static void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
+void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
 {
 	struct xhci_segment *seg;
 	struct xhci_segment *first_seg;
@@ -257,6 +257,8 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
 	if (!dev->ep_rings[0])
 		goto fail;
 
+	init_completion(&dev->cmd_completion);
+
 	/*
 	 * Point to output device context in dcbaa; skip the output control
 	 * context, which is eight 32 bit fields (or 32 bytes long)
@@ -366,6 +368,176 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud
 	return 0;
 }
 
+/* Return the polling or NAK interval.
+ *
+ * The polling interval is expressed in "microframes".  If xHCI's Interval field
+ * is set to N, it will service the endpoint every 2^(Interval)*125us.
+ *
+ * The NAK interval is one NAK per 1 to 255 microframes, or no NAKs if interval
+ * is set to 0.
+ */
+static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	unsigned int interval = 0;
+
+	switch (udev->speed) {
+	case USB_SPEED_HIGH:
+		/* Max NAK rate */
+		if (usb_endpoint_xfer_control(&ep->desc) ||
+				usb_endpoint_xfer_bulk(&ep->desc))
+			interval = ep->desc.bInterval;
+		/* Fall through - SS and HS isoc/int have same decoding */
+	case USB_SPEED_SUPER:
+		if (usb_endpoint_xfer_int(&ep->desc) ||
+				usb_endpoint_xfer_isoc(&ep->desc)) {
+			if (ep->desc.bInterval == 0)
+				interval = 0;
+			else
+				interval = ep->desc.bInterval - 1;
+			if (interval > 15)
+				interval = 15;
+			if (interval != ep->desc.bInterval + 1)
+				dev_warn(&udev->dev, "ep %#x - rounding interval to %d microframes\n",
+						ep->desc.bEndpointAddress, 1 << interval);
+		}
+		break;
+	/* Convert bInterval (in 1-255 frames) to microframes and round down to
+	 * nearest power of 2.
+	 */
+	case USB_SPEED_FULL:
+	case USB_SPEED_LOW:
+		if (usb_endpoint_xfer_int(&ep->desc) ||
+				usb_endpoint_xfer_isoc(&ep->desc)) {
+			interval = fls(8*ep->desc.bInterval) - 1;
+			if (interval > 10)
+				interval = 10;
+			if (interval < 3)
+				interval = 3;
+			if ((1 << interval) != 8*ep->desc.bInterval)
+				dev_warn(&udev->dev, "ep %#x - rounding interval to %d microframes\n",
+						ep->desc.bEndpointAddress, 1 << interval);
+		}
+		break;
+	default:
+		BUG();
+	}
+	return EP_INTERVAL(interval);
+}
+
+static inline u32 xhci_get_endpoint_type(struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	int in;
+	u32 type;
+
+	in = usb_endpoint_dir_in(&ep->desc);
+	if (usb_endpoint_xfer_control(&ep->desc)) {
+		type = EP_TYPE(CTRL_EP);
+	} else if (usb_endpoint_xfer_bulk(&ep->desc)) {
+		if (in)
+			type = EP_TYPE(BULK_IN_EP);
+		else
+			type = EP_TYPE(BULK_OUT_EP);
+	} else if (usb_endpoint_xfer_isoc(&ep->desc)) {
+		if (in)
+			type = EP_TYPE(ISOC_IN_EP);
+		else
+			type = EP_TYPE(ISOC_OUT_EP);
+	} else if (usb_endpoint_xfer_int(&ep->desc)) {
+		if (in)
+			type = EP_TYPE(INT_IN_EP);
+		else
+			type = EP_TYPE(INT_OUT_EP);
+	} else {
+		BUG();
+	}
+	return type;
+}
+
+int xhci_endpoint_init(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		struct usb_device *udev,
+		struct usb_host_endpoint *ep)
+{
+	unsigned int ep_index;
+	struct xhci_ep_ctx *ep_ctx;
+	struct xhci_ring *ep_ring;
+	unsigned int max_packet;
+	unsigned int max_burst;
+
+	ep_index = xhci_get_endpoint_index(&ep->desc);
+	ep_ctx = &virt_dev->in_ctx->ep[ep_index];
+
+	/* Set up the endpoint ring */
+	virt_dev->new_ep_rings[ep_index] = xhci_ring_alloc(xhci, 1, true, GFP_KERNEL);
+	if (!virt_dev->new_ep_rings[ep_index])
+		return -ENOMEM;
+	ep_ring = virt_dev->new_ep_rings[ep_index];
+	ep_ctx->deq[1] = 0;
+	ep_ctx->deq[0] = ep_ring->first_seg->dma | ep_ring->cycle_state;
+
+	ep_ctx->ep_info = xhci_get_endpoint_interval(udev, ep);
+
+	/* FIXME dig Mult and streams info out of ep companion desc */
+
+	/* Allow 3 retries for everything but isoc */
+	if (!usb_endpoint_xfer_isoc(&ep->desc))
+		ep_ctx->ep_info2 = ERROR_COUNT(3);
+	else
+		ep_ctx->ep_info2 = ERROR_COUNT(0);
+
+	ep_ctx->ep_info2 |= xhci_get_endpoint_type(udev, ep);
+
+	/* Set the max packet size and max burst */
+	switch (udev->speed) {
+	case USB_SPEED_SUPER:
+		max_packet = ep->desc.wMaxPacketSize;
+		ep_ctx->ep_info2 |= MAX_PACKET(max_packet);
+		/* FIXME dig out burst from ep companion desc */
+		break;
+	case USB_SPEED_HIGH:
+		/* bits 11:12 specify the number of additional transaction
+		 * opportunities per microframe (USB 2.0, section 9.6.6)
+		 */
+		if (usb_endpoint_xfer_isoc(&ep->desc) ||
+				usb_endpoint_xfer_int(&ep->desc)) {
+			max_burst = (ep->desc.wMaxPacketSize & 0x1800) >> 11;
+			ep_ctx->ep_info2 |= MAX_BURST(max_burst);
+		}
+		/* Fall through */
+	case USB_SPEED_FULL:
+	case USB_SPEED_LOW:
+		max_packet = ep->desc.wMaxPacketSize & 0x3ff;
+		ep_ctx->ep_info2 |= MAX_PACKET(max_packet);
+		break;
+	default:
+		BUG();
+	}
+	/* FIXME Debug endpoint context */
+	return 0;
+}
+
+void xhci_endpoint_zero(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		struct usb_host_endpoint *ep)
+{
+	unsigned int ep_index;
+	struct xhci_ep_ctx *ep_ctx;
+
+	ep_index = xhci_get_endpoint_index(&ep->desc);
+	ep_ctx = &virt_dev->in_ctx->ep[ep_index];
+
+	ep_ctx->ep_info = 0;
+	ep_ctx->ep_info2 = 0;
+	ep_ctx->deq[1] = 0;
+	ep_ctx->deq[0] = 0;
+	ep_ctx->tx_info = 0;
+	/* Don't free the endpoint ring until the set interface or configuration
+	 * request succeeds.
+	 */
+}
+
 void xhci_mem_cleanup(struct xhci_hcd *xhci)
 {
 	struct pci_dev	*pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ff9a4ef..1462709 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -115,6 +115,10 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	.urb_dequeue =		xhci_urb_dequeue,
 	.alloc_dev =		xhci_alloc_dev,
 	.free_dev =		xhci_free_dev,
+	.add_endpoint =		xhci_add_endpoint,
+	.drop_endpoint =	xhci_drop_endpoint,
+	.check_bandwidth =	xhci_check_bandwidth,
+	.reset_bandwidth =	xhci_reset_bandwidth,
 	.address_device =	xhci_address_device,
 
 	/*
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f04162a..b4ccf0d 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -281,6 +281,10 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 		if (xhci->devs[slot_id])
 			xhci_free_virt_device(xhci, slot_id);
 		break;
+	case TRB_TYPE(TRB_CONFIG_EP):
+		xhci->devs[slot_id]->cmd_status = GET_COMP_CODE(event->status);
+		complete(&xhci->devs[slot_id]->cmd_completion);
+		break;
 	case TRB_TYPE(TRB_ADDR_DEV):
 		xhci->devs[slot_id]->cmd_status = GET_COMP_CODE(event->status);
 		complete(&xhci->addr_dev);
@@ -809,3 +813,10 @@ int queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_
 	return queue_command(xhci, in_ctx_ptr, 0, 0,
 			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id));
 }
+
+/* Queue a configure endpoint command TRB */
+int queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_id)
+{
+	return queue_command(xhci, in_ctx_ptr, 0, 0,
+			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id));
+}
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fc8dcd2..1a6fd99 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -486,8 +486,6 @@ struct xhci_slot_ctx {
 #define LAST_CTX_MASK	(0x1f << 27)
 #define LAST_CTX(p)	((p) << 27)
 #define LAST_CTX_TO_EP_NUM(p)	(((p) >> 27) - 1)
-/* Plus one for the slot context flag */
-#define EPI_TO_FLAG(p)	(1 << ((p) + 1))
 #define SLOT_FLAG	(1 << 0)
 #define EP0_FLAG	(1 << 1)
 
@@ -566,7 +564,7 @@ struct xhci_ep_ctx {
 /* bits 10:14 are Max Primary Streams */
 /* bit 15 is Linear Stream Array */
 /* Interval - period between requests to an endpoint - 125u increments. */
-#define EP_INTERVAL		(0xff << 16)
+#define EP_INTERVAL(p)		((p & 0xff) << 16)
 
 /* ep_info2 bitmasks */
 /*
@@ -626,6 +624,11 @@ struct xhci_virt_device {
 	dma_addr_t			in_ctx_dma;
 	/* FIXME when stream support is added */
 	struct xhci_ring		*ep_rings[31];
+	/* Temporary storage in case the configure endpoint command fails and we
+	 * have to restore the device state to the previous state
+	 */
+	struct xhci_ring		*new_ep_rings[31];
+	struct completion		cmd_completion;
 	/* Status of the last command issued for this device */
 	u32				cmd_status;
 };
@@ -1075,6 +1078,10 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id);
 int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, struct usb_device *udev, gfp_t flags);
 int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *udev);
 unsigned int xhci_get_endpoint_index(struct usb_endpoint_descriptor *desc);
+unsigned int xhci_get_endpoint_flag(struct usb_endpoint_descriptor *desc);
+void xhci_endpoint_zero(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev, struct usb_host_endpoint *ep);
+int xhci_endpoint_init(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev, struct usb_device *udev, struct usb_host_endpoint *ep);
+void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring);
 
 #ifdef CONFIG_PCI
 /* xHCI PCI glue */
@@ -1096,6 +1103,10 @@ void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev);
 int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev);
 int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags);
 int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status);
+int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev, struct usb_host_endpoint *ep);
+int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev, struct usb_host_endpoint *ep);
+int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev);
+void xhci_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev);
 
 /* xHCI ring, segment, TRB, and TD functions */
 dma_addr_t trb_virt_to_dma(struct xhci_segment *seg, union xhci_trb *trb);
@@ -1106,6 +1117,7 @@ void set_hc_event_deq(struct xhci_hcd *xhci);
 int queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id);
 int queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_id);
 int queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb, int slot_id, unsigned int ep_index);
+int queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_id);
 
 /* xHCI roothub code */
 int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,