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.
+unsigned int xhci_get_block_size(struct usb_device *udev)
+{
+ switch (udev->speed) {
+ case USB_SPEED_LOW:
+ case USB_SPEED_FULL:
+ return FS_BLOCK;
+ case USB_SPEED_HIGH:
+ return HS_BLOCK;
+ case USB_SPEED_SUPER:
+ return SS_BLOCK;
+ case USB_SPEED_UNKNOWN:
+ case USB_SPEED_WIRELESS:
+ default:
+ /* Should never happen */
+ return 1;
+ }
+}
+
+unsigned int xhci_get_largest_overhead(struct xhci_interval_bw *interval_bw)
+{
+ if (interval_bw->overhead[LS_OVERHEAD_TYPE])
+ return LS_OVERHEAD;
+ if (interval_bw->overhead[FS_OVERHEAD_TYPE])
+ return FS_OVERHEAD;
+ return HS_OVERHEAD;
+}
+
+/* If we are changing a LS/FS device under a HS hub,
+ * make sure (if we are activating a new TT) that the HS bus has enough
+ * bandwidth for this new TT.
+ */
+static int xhci_check_tt_bw_table(struct xhci_hcd *xhci,
+ struct xhci_virt_device *virt_dev,
+ int old_active_eps)
+{
+ struct xhci_interval_bw_table *bw_table;
+ struct xhci_tt_bw_info *tt_info;
+
+ /* Find the bandwidth table for the root port this TT is attached to. */
+ bw_table = &xhci->rh_bw[virt_dev->real_port - 1].bw_table;
+ tt_info = virt_dev->tt_info;
+ /* If this TT already had active endpoints, the bandwidth for this TT
+ * has already been added. Removing all periodic endpoints (and thus
+ * making the TT enactive) will only decrease the bandwidth used.
+ */
+ if (old_active_eps)
+ return 0;
+ if (old_active_eps == 0 && tt_info->active_eps != 0) {
+ if (bw_table->bw_used + TT_HS_OVERHEAD > HS_BW_LIMIT)
+ return -ENOMEM;
+ return 0;
+ }
+ /* Not sure why we would have no new active endpoints...
+ *
+ * Maybe because of an Evaluate Context change for a hub update or a
+ * control endpoint 0 max packet size change?
+ * FIXME: skip the bandwidth calculation in that case.
+ */
+ return 0;
+}
+
+/*
+ * This algorithm is a very conservative estimate of the worst-case scheduling
+ * scenario for any one interval. The hardware dynamically schedules the
+ * packets, so we can't tell which microframe could be the limiting factor in
+ * the bandwidth scheduling. This only takes into account periodic endpoints.
+ *
+ * Obviously, we can't solve an NP complete problem to find the minimum worst
+ * case scenario. Instead, we come up with an estimate that is no less than
+ * the worst case bandwidth used for any one microframe, but may be an
+ * over-estimate.
+ *
+ * We walk the requirements for each endpoint by interval, starting with the
+ * smallest interval, and place packets in the schedule where there is only one
+ * possible way to schedule packets for that interval. In order to simplify
+ * this algorithm, we record the largest max packet size for each interval, and
+ * assume all packets will be that size.
+ *
+ * For interval 0, we obviously must schedule all packets for each interval.
+ * The bandwidth for interval 0 is just the amount of data to be transmitted
+ * (the sum of all max ESIT payload sizes, plus any overhead per packet times
+ * the number of packets).
+ *
+ * For interval 1, we have two possible microframes to schedule those packets
+ * in. For this algorithm, if we can schedule the same number of packets for
+ * each possible scheduling opportunity (each microframe), we will do so. The
+ * remaining number of packets will be saved to be transmitted in the gaps in
+ * the next interval's scheduling sequence.
+ *
+ * As we move those remaining packets to be scheduled with interval 2 packets,
+ * we have to double the number of remaining packets to transmit. This is
+ * because the intervals are actually powers of 2, and we would be transmitting
+ * the previous interval's packets twice in this interval. We also have to be
+ * sure that when we look at the largest max packet size for this interval, we
+ * also look at the largest max packet size for the remaining packets and take
+ * the greater of the two.
+ *
+ * The algorithm continues to evenly distribute packets in each scheduling
+ * opportunity, and push the remaining packets out, until we get to the last
+ * interval. Then those packets and their associated overhead are just added
+ * to the bandwidth used.
*/
static int xhci_check_bw_table(struct xhci_hcd *xhci,
struct xhci_virt_device *virt_dev,
int old_active_eps)
{
+ unsigned int bw_reserved;
+ unsigned int max_bandwidth;
+ unsigned int bw_used;
+ unsigned int block_size;
+ struct xhci_interval_bw_table *bw_table;
+ unsigned int packet_size = 0;
+ unsigned int overhead = 0;
+ unsigned int packets_transmitted = 0;
+ unsigned int packets_remaining = 0;
+ unsigned int i;
+
+ if (virt_dev->udev->speed == USB_SPEED_HIGH) {
+ max_bandwidth = HS_BW_LIMIT;
+ /* Convert percent of bus BW reserved to blocks reserved */
+ bw_reserved = DIV_ROUND_UP(HS_BW_RESERVED * max_bandwidth, 100);
+ } else {
+ max_bandwidth = FS_BW_LIMIT;
+ bw_reserved = DIV_ROUND_UP(FS_BW_RESERVED * max_bandwidth, 100);
+ }
+
+ bw_table = virt_dev->bw_table;
+ /* We need to translate the max packet size and max ESIT payloads into
+ * the units the hardware uses.
+ */
+ block_size = xhci_get_block_size(virt_dev->udev);
+
+ /* If we are manipulating a LS/FS device under a HS hub, double check
+ * that the HS bus has enough bandwidth if we are activing a new TT.
+ */
+ if (virt_dev->tt_info) {
+ xhci_dbg(xhci, "Recalculating BW for rootport %u\n",
+ virt_dev->real_port);
+ if (xhci_check_tt_bw_table(xhci, virt_dev, old_active_eps)) {
+ xhci_warn(xhci, "Not enough bandwidth on HS bus for "
+ "newly activated TT.\n");
+ return -ENOMEM;
+ }
+ xhci_dbg(xhci, "Recalculating BW for TT slot %u port %u\n",
+ virt_dev->tt_info->slot_id,
+ virt_dev->tt_info->ttport);
+ } else {
+ xhci_dbg(xhci, "Recalculating BW for rootport %u\n",
+ virt_dev->real_port);
+ }
+
+ /* Add in how much bandwidth will be used for interval zero, or the
+ * rounded max ESIT payload + number of packets * largest overhead.
+ */
+ bw_used = DIV_ROUND_UP(bw_table->interval0_esit_payload, block_size) +
+ bw_table->interval_bw[0].num_packets *
+ xhci_get_largest_overhead(&bw_table->interval_bw[0]);
+
+ for (i = 1; i < XHCI_MAX_INTERVAL; i++) {
+ unsigned int bw_added;
+ unsigned int largest_mps;
+ unsigned int interval_overhead;
+
+ /*
+ * How many packets could we transmit in this interval?
+ * If packets didn't fit in the previous interval, we will need
+ * to transmit that many packets twice within this interval.
+ */
+ packets_remaining = 2 * packets_remaining +
+ bw_table->interval_bw[i].num_packets;
+
+ /* Find the largest max packet size of this or the previous
+ * interval.
+ */
+ if (list_empty(&bw_table->interval_bw[i].endpoints))
+ largest_mps = 0;
+ else {
+ struct xhci_virt_ep *virt_ep;
+ struct list_head *ep_entry;
+
+ ep_entry = bw_table->interval_bw[i].endpoints.next;
+ virt_ep = list_entry(ep_entry,
+ struct xhci_virt_ep, bw_endpoint_list);
+ /* Convert to blocks, rounding up */
+ largest_mps = DIV_ROUND_UP(
+ virt_ep->bw_info.max_packet_size,
+ block_size);
+ }
+ if (largest_mps > packet_size)
+ packet_size = largest_mps;
+
+ /* Use the larger overhead of this or the previous interval. */
+ interval_overhead = xhci_get_largest_overhead(
+ &bw_table->interval_bw[i]);
+ if (interval_overhead > overhead)
+ overhead = interval_overhead;
+
+ /* How many packets can we evenly distribute across
+ * (1 << (i + 1)) possible scheduling opportunities?
+ */
+ packets_transmitted = packets_remaining >> (i + 1);
+
+ /* Add in the bandwidth used for those scheduled packets */
+ bw_added = packets_transmitted * (overhead + packet_size);
+
+ /* How many packets do we have remaining to transmit? */
+ packets_remaining = packets_remaining % (1 << (i + 1));
+
+ /* What largest max packet size should those packets have? */
+ /* If we've transmitted all packets, don't carry over the
+ * largest packet size.
+ */
+ if (packets_remaining == 0) {
+ packet_size = 0;
+ overhead = 0;
+ } else if (packets_transmitted > 0) {
+ /* Otherwise if we do have remaining packets, and we've
+ * scheduled some packets in this interval, take the
+ * largest max packet size from endpoints with this
+ * interval.
+ */
+ packet_size = largest_mps;
+ overhead = interval_overhead;
+ }
+ /* Otherwise carry over packet_size and overhead from the last
+ * time we had a remainder.
+ */
+ bw_used += bw_added;
+ if (bw_used > max_bandwidth) {
+ xhci_warn(xhci, "Not enough bandwidth. "
+ "Proposed: %u, Max: %u\n",
+ bw_used, max_bandwidth);
+ return -ENOMEM;
+ }
+ }
+ /*
+ * Ok, we know we have some packets left over after even-handedly
+ * scheduling interval 15. We don't know which microframes they will
+ * fit into, so we over-schedule and say they will be scheduled every
+ * microframe.
+ */
+ if (packets_remaining > 0)
+ bw_used += overhead + packet_size;
+
+ if (!virt_dev->tt_info && virt_dev->udev->speed == USB_SPEED_HIGH) {
+ unsigned int port_index = virt_dev->real_port - 1;
+
+ /* OK, we're manipulating a HS device attached to a
+ * root port bandwidth domain. Include the number of active TTs
+ * in the bandwidth used.
+ */
+ bw_used += TT_HS_OVERHEAD *
+ xhci->rh_bw[port_index].num_active_tts;
+ }
+
+ xhci_dbg(xhci, "Final bandwidth: %u, Limit: %u, Reserved: %u, "
+ "Available: %u " "percent\n",
+ bw_used, max_bandwidth, bw_reserved,
+ (max_bandwidth - bw_used - bw_reserved) * 100 /
+ max_bandwidth);
+
+ bw_used += bw_reserved;
+ if (bw_used > max_bandwidth) {
+ xhci_warn(xhci, "Not enough bandwidth. Proposed: %u, Max: %u\n",
+ bw_used, max_bandwidth);
+ return -ENOMEM;
+ }
+
+ bw_table->bw_used = bw_used;
return 0;
}
if (old_active_eps == 0 &&
virt_dev->tt_info->active_eps != 0) {
rh_bw_info->num_active_tts += 1;
+ rh_bw_info->bw_table.bw_used += TT_HS_OVERHEAD;
} else if (old_active_eps != 0 &&
virt_dev->tt_info->active_eps == 0) {
rh_bw_info->num_active_tts -= 1;
+ rh_bw_info->bw_table.bw_used -= TT_HS_OVERHEAD;
}
}
unsigned int type;
};
+/* "Block" sizes in bytes the hardware uses for different device speeds.
+ * The logic in this part of the hardware limits the number of bits the hardware
+ * can use, so must represent bandwidth in a less precise manner to mimic what
+ * the scheduler hardware computes.
+ */
+#define FS_BLOCK 1
+#define HS_BLOCK 4
+#define SS_BLOCK 16
+#define DMI_BLOCK 32
+
+/* Each device speed has a protocol overhead (CRC, bit stuffing, etc) associated
+ * with each byte transferred. SuperSpeed devices have an initial overhead to
+ * set up bursts. These are in blocks, see above. LS overhead has already been
+ * translated into FS blocks.
+ */
+#define DMI_OVERHEAD 8
+#define DMI_OVERHEAD_BURST 4
+#define SS_OVERHEAD 8
+#define SS_OVERHEAD_BURST 32
+#define HS_OVERHEAD 26
+#define FS_OVERHEAD 20
+#define LS_OVERHEAD 128
+/* The TTs need to claim roughly twice as much bandwidth (94 bytes per
+ * microframe ~= 24Mbps) of the HS bus as the devices can actually use because
+ * of overhead associated with split transfers crossing microframe boundaries.
+ * 31 blocks is pure protocol overhead.
+ */
+#define TT_HS_OVERHEAD (31 + 94)
+#define TT_DMI_OVERHEAD (25 + 12)
+
+/* Bandwidth limits in blocks */
+#define FS_BW_LIMIT 1285
+#define TT_BW_LIMIT 1320
+#define HS_BW_LIMIT 1607
+#define SS_BW_LIMIT_IN 3906
+#define DMI_BW_LIMIT_IN 3906
+#define SS_BW_LIMIT_OUT 3906
+#define DMI_BW_LIMIT_OUT 3906
+
+/* Percentage of bus bandwidth reserved for non-periodic transfers */
+#define FS_BW_RESERVED 10
+#define HS_BW_RESERVED 20
+
struct xhci_virt_ep {
struct xhci_ring *ring;
/* Related to endpoints that are configured to use stream IDs only */
struct xhci_interval_bw_table {
unsigned int interval0_esit_payload;
struct xhci_interval_bw interval_bw[XHCI_MAX_INTERVAL];
+ /* Includes reserved bandwidth for async endpoints */
+ unsigned int bw_used;
};
#define XHCI_EP_LIMIT_QUIRK (1 << 5)
#define XHCI_BROKEN_MSI (1 << 6)
#define XHCI_RESET_ON_RESUME (1 << 7)
+#define XHCI_SW_BW_CHECKING (1 << 8)
unsigned int num_active_eps;
unsigned int limit_active_eps;
/* There are two roothubs to keep track of bus suspend info for */
projects / linux.git / commitdiff