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>

1 files changed, 173 insertions, 1 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 6ff2e298bff..8cd55f03ea2 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);