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>

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);

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,
 
 	/*

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));
+}

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,