diff options
| -rw-r--r-- | drivers/usb/host/xhci.c | 268 | ||||
| -rw-r--r-- | drivers/usb/host/xhci.h | 46 |
2 files changed, 312 insertions, 2 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 51c4d385b77..40b82f7e429 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1747,13 +1747,275 @@ 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. +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; } @@ -1888,9 +2150,11 @@ void xhci_update_tt_active_eps(struct xhci_hcd *xhci, 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; } } diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 050f07b1e79..b224b20b078 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -756,6 +756,49 @@ struct xhci_bw_info { 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 */ @@ -823,6 +866,8 @@ struct xhci_interval_bw { 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; }; @@ -1397,6 +1442,7 @@ struct xhci_hcd { #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 */ |