xhci: Track interval bandwidth tables per port/TT.

In order to update the root port or TT's bandwidth interval table, we will
need to keep track of a list of endpoints, per interval.  That way we can
easily know the new largest max packet size when we have to remove an
endpoint.

Add an endpoint list for each root port or TT structure, sorted by
endpoint max packet size.  Insert new endpoints into the list such that
the head of the list always has the endpoint with the greatest max packet
size.  Only insert endpoints and update the interval table with new
information when those endpoints are periodic.

Make sure to update the number of active TTs when we add or drop periodic
endpoints.  A TT is only considered active if it has one or more periodic
endpoints attached (control and bulk are best effort, and counted in the
20% reserved on the high speed bus).  If the number of active endpoints
for a TT was zero, and it's now non-zero, increment the number of active
TTs for the rootport.  If the number of active endpoints was non-zero, and
it's now zero, decrement the number of active TTs.

We have to be careful when we're checking the bandwidth for a new
configuration/alt setting.  If we don't have enough bandwidth, we need to
be able to "roll back" the bandwidth information stored in the endpoint
and the root port/TT interval bandwidth table.  We can't just create a
copy of the interval bandwidth table, modify it, and check the bandwidth
with the copy because we have lists of endpoints and entries can't be on
more than one list.  Instead, we copy the old endpoint bandwidth
information, and use it to revert the interval table when the bandwidth
check fails.

We don't check the bandwidth after endpoints are dropped from the interval
table when a device is reset or freed after a disconnect, because having
endpoints use less bandwidth should not push the bandwidth usage over the
limits.  Besides which, we can't fail a device disconnect.
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

@@ -783,6 +783,7 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
 {
 	struct xhci_virt_device *dev;
 	int i;
+	int old_active_eps = 0;
 
 	/* Slot ID 0 is reserved */
 	if (slot_id == 0 || !xhci->devs[slot_id])
@@ -793,15 +794,29 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
 	if (!dev)
 		return;
 
+	if (dev->tt_info)
+		old_active_eps = dev->tt_info->active_eps;
+
 	for (i = 0; i < 31; ++i) {
 		if (dev->eps[i].ring)
 			xhci_ring_free(xhci, dev->eps[i].ring);
 		if (dev->eps[i].stream_info)
 			xhci_free_stream_info(xhci,
 					dev->eps[i].stream_info);
+		/* Endpoints on the TT/root port lists should have been removed
+		 * when usb_disable_device() was called for the device.
+		 * We can't drop them anyway, because the udev might have gone
+		 * away by this point, and we can't tell what speed it was.
+		 */
+		if (!list_empty(&dev->eps[i].bw_endpoint_list))
+			xhci_warn(xhci, "Slot %u endpoint %u "
+					"not removed from BW list!\n",
+					slot_id, i);
 	}
 	/* If this is a hub, free the TT(s) from the TT list */
 	xhci_free_tt_info(xhci, dev, slot_id);
+	/* If necessary, update the number of active TTs on this root port */
+	xhci_update_tt_active_eps(xhci, dev, old_active_eps);
 
 	if (dev->ring_cache) {
 		for (i = 0; i < dev->num_rings_cached; i++)
@@ -855,6 +870,7 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
 	for (i = 0; i < 31; i++) {
 		xhci_init_endpoint_timer(xhci, &dev->eps[i]);
 		INIT_LIST_HEAD(&dev->eps[i].cancelled_td_list);
+		INIT_LIST_HEAD(&dev->eps[i].bw_endpoint_list);
 	}
 
 	/* Allocate endpoint 0 ring */
@@ -1994,7 +2010,7 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 	__le32 __iomem *addr;
 	u32 offset;
 	unsigned int num_ports;
-	int i, port_index;
+	int i, j, port_index;
 
 	addr = &xhci->cap_regs->hcc_params;
 	offset = XHCI_HCC_EXT_CAPS(xhci_readl(xhci, addr));
@@ -2012,8 +2028,14 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 	xhci->rh_bw = kzalloc(sizeof(*xhci->rh_bw)*num_ports, flags);
 	if (!xhci->rh_bw)
 		return -ENOMEM;
-	for (i = 0; i < num_ports; i++)
+	for (i = 0; i < num_ports; i++) {
+		struct xhci_interval_bw_table *bw_table;
+
 		INIT_LIST_HEAD(&xhci->rh_bw[i].tts);
+		bw_table = &xhci->rh_bw[i].bw_table;
+		for (j = 0; j < XHCI_MAX_INTERVAL; j++)
+			INIT_LIST_HEAD(&bw_table->interval_bw[j].endpoints);
+	}
 
 	/*
 	 * For whatever reason, the first capability offset is from the

drivers/usb/host/xhci.c

@@ -1747,6 +1747,241 @@ static void xhci_finish_resource_reservation(struct xhci_hcd *xhci,
 				xhci->num_active_eps);
 }
 
+/* Run the algorithm on the bandwidth table.  If this table is part of a
+ * TT, see if we need to update the number of active TTs.
+ */
+static int xhci_check_bw_table(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		int old_active_eps)
+{
+	return 0;
+}
+
+static bool xhci_is_async_ep(unsigned int ep_type)
+{
+	return (ep_type != ISOC_OUT_EP && ep_type != INT_OUT_EP &&
+					ep_type != ISOC_IN_EP &&
+					ep_type != INT_IN_EP);
+}
+
+void xhci_drop_ep_from_interval_table(struct xhci_hcd *xhci,
+		struct xhci_bw_info *ep_bw,
+		struct xhci_interval_bw_table *bw_table,
+		struct usb_device *udev,
+		struct xhci_virt_ep *virt_ep,
+		struct xhci_tt_bw_info *tt_info)
+{
+	struct xhci_interval_bw	*interval_bw;
+	int normalized_interval;
+
+	if (xhci_is_async_ep(ep_bw->type) ||
+			list_empty(&virt_ep->bw_endpoint_list))
+		return;
+
+	/* For LS/FS devices, we need to translate the interval expressed in
+	 * microframes to frames.
+	 */
+	if (udev->speed == USB_SPEED_HIGH)
+		normalized_interval = ep_bw->ep_interval;
+	else
+		normalized_interval = ep_bw->ep_interval - 3;
+
+	if (normalized_interval == 0)
+		bw_table->interval0_esit_payload -= ep_bw->max_esit_payload;
+	interval_bw = &bw_table->interval_bw[normalized_interval];
+	interval_bw->num_packets -= ep_bw->num_packets;
+	switch (udev->speed) {
+	case USB_SPEED_LOW:
+		interval_bw->overhead[LS_OVERHEAD_TYPE] -= 1;
+		break;
+	case USB_SPEED_FULL:
+		interval_bw->overhead[FS_OVERHEAD_TYPE] -= 1;
+		break;
+	case USB_SPEED_HIGH:
+		interval_bw->overhead[HS_OVERHEAD_TYPE] -= 1;
+		break;
+	case USB_SPEED_SUPER:
+	case USB_SPEED_UNKNOWN:
+	case USB_SPEED_WIRELESS:
+		/* Should never happen because only LS/FS/HS endpoints will get
+		 * added to the endpoint list.
+		 */
+		return;
+	}
+	if (tt_info)
+		tt_info->active_eps -= 1;
+	list_del_init(&virt_ep->bw_endpoint_list);
+}
+
+static void xhci_add_ep_to_interval_table(struct xhci_hcd *xhci,
+		struct xhci_bw_info *ep_bw,
+		struct xhci_interval_bw_table *bw_table,
+		struct usb_device *udev,
+		struct xhci_virt_ep *virt_ep,
+		struct xhci_tt_bw_info *tt_info)
+{
+	struct xhci_interval_bw	*interval_bw;
+	struct xhci_virt_ep *smaller_ep;
+	int normalized_interval;
+
+	if (xhci_is_async_ep(ep_bw->type))
+		return;
+
+	/* For LS/FS devices, we need to translate the interval expressed in
+	 * microframes to frames.
+	 */
+	if (udev->speed == USB_SPEED_HIGH)
+		normalized_interval = ep_bw->ep_interval;
+	else
+		normalized_interval = ep_bw->ep_interval - 3;
+
+	if (normalized_interval == 0)
+		bw_table->interval0_esit_payload += ep_bw->max_esit_payload;
+	interval_bw = &bw_table->interval_bw[normalized_interval];
+	interval_bw->num_packets += ep_bw->num_packets;
+	switch (udev->speed) {
+	case USB_SPEED_LOW:
+		interval_bw->overhead[LS_OVERHEAD_TYPE] += 1;
+		break;
+	case USB_SPEED_FULL:
+		interval_bw->overhead[FS_OVERHEAD_TYPE] += 1;
+		break;
+	case USB_SPEED_HIGH:
+		interval_bw->overhead[HS_OVERHEAD_TYPE] += 1;
+		break;
+	case USB_SPEED_SUPER:
+	case USB_SPEED_UNKNOWN:
+	case USB_SPEED_WIRELESS:
+		/* Should never happen because only LS/FS/HS endpoints will get
+		 * added to the endpoint list.
+		 */
+		return;
+	}
+
+	if (tt_info)
+		tt_info->active_eps += 1;
+	/* Insert the endpoint into the list, largest max packet size first. */
+	list_for_each_entry(smaller_ep, &interval_bw->endpoints,
+			bw_endpoint_list) {
+		if (ep_bw->max_packet_size >=
+				smaller_ep->bw_info.max_packet_size) {
+			/* Add the new ep before the smaller endpoint */
+			list_add_tail(&virt_ep->bw_endpoint_list,
+					&smaller_ep->bw_endpoint_list);
+			return;
+		}
+	}
+	/* Add the new endpoint at the end of the list. */
+	list_add_tail(&virt_ep->bw_endpoint_list,
+			&interval_bw->endpoints);
+}
+
+void xhci_update_tt_active_eps(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		int old_active_eps)
+{
+	struct xhci_root_port_bw_info *rh_bw_info;
+	if (!virt_dev->tt_info)
+		return;
+
+	rh_bw_info = &xhci->rh_bw[virt_dev->real_port - 1];
+	if (old_active_eps == 0 &&
+				virt_dev->tt_info->active_eps != 0) {
+		rh_bw_info->num_active_tts += 1;
+	} else if (old_active_eps != 0 &&
+				virt_dev->tt_info->active_eps == 0) {
+		rh_bw_info->num_active_tts -= 1;
+	}
+}
+
+static int xhci_reserve_bandwidth(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		struct xhci_container_ctx *in_ctx)
+{
+	struct xhci_bw_info ep_bw_info[31];
+	int i;
+	struct xhci_input_control_ctx *ctrl_ctx;
+	int old_active_eps = 0;
+
+	if (virt_dev->udev->speed == USB_SPEED_SUPER)
+		return 0;
+
+	if (virt_dev->tt_info)
+		old_active_eps = virt_dev->tt_info->active_eps;
+
+	ctrl_ctx = xhci_get_input_control_ctx(xhci, in_ctx);
+
+	for (i = 0; i < 31; i++) {
+		if (!EP_IS_ADDED(ctrl_ctx, i) && !EP_IS_DROPPED(ctrl_ctx, i))
+			continue;
+
+		/* Make a copy of the BW info in case we need to revert this */
+		memcpy(&ep_bw_info[i], &virt_dev->eps[i].bw_info,
+				sizeof(ep_bw_info[i]));
+		/* Drop the endpoint from the interval table if the endpoint is
+		 * being dropped or changed.
+		 */
+		if (EP_IS_DROPPED(ctrl_ctx, i))
+			xhci_drop_ep_from_interval_table(xhci,
+					&virt_dev->eps[i].bw_info,
+					virt_dev->bw_table,
+					virt_dev->udev,
+					&virt_dev->eps[i],
+					virt_dev->tt_info);
+	}
+	/* Overwrite the information stored in the endpoints' bw_info */
+	xhci_update_bw_info(xhci, virt_dev->in_ctx, ctrl_ctx, virt_dev);
+	for (i = 0; i < 31; i++) {
+		/* Add any changed or added endpoints to the interval table */
+		if (EP_IS_ADDED(ctrl_ctx, i))
+			xhci_add_ep_to_interval_table(xhci,
+					&virt_dev->eps[i].bw_info,
+					virt_dev->bw_table,
+					virt_dev->udev,
+					&virt_dev->eps[i],
+					virt_dev->tt_info);
+	}
+
+	if (!xhci_check_bw_table(xhci, virt_dev, old_active_eps)) {
+		/* Ok, this fits in the bandwidth we have.
+		 * Update the number of active TTs.
+		 */
+		xhci_update_tt_active_eps(xhci, virt_dev, old_active_eps);
+		return 0;
+	}
+
+	/* We don't have enough bandwidth for this, revert the stored info. */
+	for (i = 0; i < 31; i++) {
+		if (!EP_IS_ADDED(ctrl_ctx, i) && !EP_IS_DROPPED(ctrl_ctx, i))
+			continue;
+
+		/* Drop the new copies of any added or changed endpoints from
+		 * the interval table.
+		 */
+		if (EP_IS_ADDED(ctrl_ctx, i)) {
+			xhci_drop_ep_from_interval_table(xhci,
+					&virt_dev->eps[i].bw_info,
+					virt_dev->bw_table,
+					virt_dev->udev,
+					&virt_dev->eps[i],
+					virt_dev->tt_info);
+		}
+		/* Revert the endpoint back to its old information */
+		memcpy(&virt_dev->eps[i].bw_info, &ep_bw_info[i],
+				sizeof(ep_bw_info[i]));
+		/* Add any changed or dropped endpoints back into the table */
+		if (EP_IS_DROPPED(ctrl_ctx, i))
+			xhci_add_ep_to_interval_table(xhci,
+					&virt_dev->eps[i].bw_info,
+					virt_dev->bw_table,
+					virt_dev->udev,
+					&virt_dev->eps[i],
+					virt_dev->tt_info);
+	}
+	return -ENOMEM;
+}
+
+
 /* Issue a configure endpoint command or evaluate context command
  * and wait for it to finish.
  */
@@ -1779,6 +2014,14 @@ static int xhci_configure_endpoint(struct xhci_hcd *xhci,
 				xhci->num_active_eps);
 		return -ENOMEM;
 	}
+	if ((xhci->quirks & XHCI_SW_BW_CHECKING) &&
+			xhci_reserve_bandwidth(xhci, virt_dev, in_ctx)) {
+		if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK))
+			xhci_free_host_resources(xhci, in_ctx);
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		xhci_warn(xhci, "Not enough bandwidth\n");
+		return -ENOMEM;
+	}
 
 	if (command) {
 		cmd_completion = command->completion;
@@ -1912,7 +2155,6 @@ int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
 		    !(le32_to_cpu(ctrl_ctx->add_flags) & (1 << (i + 1))))
 			xhci_free_or_cache_endpoint_ring(xhci, virt_dev, i);
 	}
-	xhci_update_bw_info(xhci, virt_dev->in_ctx, ctrl_ctx, virt_dev);
 	xhci_zero_in_ctx(xhci, virt_dev);
 	/*
 	 * Install any rings for completely new endpoints or changed endpoints,
@@ -2528,6 +2770,7 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
 	int timeleft;
 	int last_freed_endpoint;
 	struct xhci_slot_ctx *slot_ctx;
+	int old_active_eps = 0;
 
 	ret = xhci_check_args(hcd, udev, NULL, 0, false, __func__);
 	if (ret <= 0)
@@ -2669,8 +2912,18 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
 			xhci_free_or_cache_endpoint_ring(xhci, virt_dev, i);
 			last_freed_endpoint = i;
 		}
+		if (!list_empty(&virt_dev->eps[i].bw_endpoint_list))
+			xhci_drop_ep_from_interval_table(xhci,
+					&virt_dev->eps[i].bw_info,
+					virt_dev->bw_table,
+					udev,
+					&virt_dev->eps[i],
+					virt_dev->tt_info);
 		xhci_clear_endpoint_bw_info(&virt_dev->eps[i].bw_info);
 	}
+	/* If necessary, update the number of active TTs on this root port */
+	xhci_update_tt_active_eps(xhci, virt_dev, old_active_eps);
+
 	xhci_dbg(xhci, "Output context after successful reset device cmd:\n");
 	xhci_dbg_ctx(xhci, virt_dev->out_ctx, last_freed_endpoint);
 	ret = 0;

drivers/usb/host/xhci.h

@@ -797,7 +797,9 @@ struct xhci_virt_ep {
 	 * process the missed tds on the endpoint ring.
 	 */
 	bool			skip;
+	/* Bandwidth checking storage */
 	struct xhci_bw_info	bw_info;
+	struct list_head	bw_endpoint_list;
 };
 
 enum xhci_overhead_type {
@@ -808,6 +810,10 @@ enum xhci_overhead_type {
 
 struct xhci_interval_bw {
 	unsigned int		num_packets;
+	/* Sorted by max packet size.
+	 * Head of the list is the greatest max packet size.
+	 */
+	struct list_head	endpoints;
 	/* How many endpoints of each speed are present. */
 	unsigned int		overhead[3];
 };
@@ -1511,6 +1517,15 @@ unsigned int xhci_get_endpoint_flag(struct usb_endpoint_descriptor *desc);
 unsigned int xhci_get_endpoint_flag_from_index(unsigned int ep_index);
 unsigned int xhci_last_valid_endpoint(u32 added_ctxs);
 void xhci_endpoint_zero(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev, struct usb_host_endpoint *ep);
+void xhci_drop_ep_from_interval_table(struct xhci_hcd *xhci,
+		struct xhci_bw_info *ep_bw,
+		struct xhci_interval_bw_table *bw_table,
+		struct usb_device *udev,
+		struct xhci_virt_ep *virt_ep,
+		struct xhci_tt_bw_info *tt_info);
+void xhci_update_tt_active_eps(struct xhci_hcd *xhci,
+		struct xhci_virt_device *virt_dev,
+		int old_active_eps);
 void xhci_clear_endpoint_bw_info(struct xhci_bw_info *bw_info);
 void xhci_update_bw_info(struct xhci_hcd *xhci,
 		struct xhci_container_ctx *in_ctx,