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>

1 files changed, 24 insertions, 2 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 9451d94b78d..1c5c9ba141d 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/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