diff options
| -rw-r--r-- | drivers/usb/dwc2/hcd.h | 10 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd_queue.c | 351 |
2 files changed, 272 insertions, 89 deletions
diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h index 10c35585a2bd..fd266ac53a28 100644 --- a/drivers/usb/dwc2/hcd.h +++ b/drivers/usb/dwc2/hcd.h @@ -244,8 +244,11 @@ enum dwc2_transaction_type { * the bus. We'll move the qh to active here. If the * host is in high speed mode this will be a uframe. If * the host is in low speed mode this will be a full frame. + * @start_active_frame: If we are partway through a split transfer, this will be + * what next_active_frame was when we started. Otherwise + * it should always be the same as next_active_frame. + * @assigned_uframe: The uframe (0 -7) assigned by dwc2_find_uframe(). * @frame_usecs: Internal variable used by the microframe scheduler - * @start_split_frame: (Micro)frame at which last start split was initialized * @ntd: Actual number of transfer descriptors in a list * @qtd_list: List of QTDs for this QH * @channel: Host channel currently processing transfers for this QH @@ -279,8 +282,9 @@ struct dwc2_qh { u16 host_us; u16 host_interval; u16 next_active_frame; + u16 start_active_frame; + u16 assigned_uframe; u16 frame_usecs[8]; - u16 start_split_frame; u16 ntd; struct list_head qtd_list; struct dwc2_host_chan *channel; @@ -746,7 +750,7 @@ do { \ _qtd_ = list_entry((_qh_)->qtd_list.next, struct dwc2_qtd, \ qtd_list_entry); \ if (usb_pipeint(_qtd_->urb->pipe) && \ - (_qh_)->start_split_frame != 0 && !_qtd_->complete_split) { \ + (_qh_)->start_active_frame != 0 && !_qtd_->complete_split) { \ _hfnum_.d32 = dwc2_readl((_hcd_)->regs + HFNUM); \ switch (_hfnum_.b.frnum & 0x7) { \ case 7: \ diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c index 9ce407e5017d..9b3c435339ee 100644 --- a/drivers/usb/dwc2/hcd_queue.c +++ b/drivers/usb/dwc2/hcd_queue.c @@ -38,6 +38,7 @@ * This file contains the functions to manage Queue Heads and Queue * Transfer Descriptors for Host mode */ +#include <linux/gcd.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/spinlock.h> @@ -245,6 +246,96 @@ static int dwc2_find_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) } /** + * dwc2_pick_first_frame() - Choose 1st frame for qh that's already scheduled + * + * Takes a qh that has already been scheduled (which means we know we have the + * bandwdith reserved for us) and set the next_active_frame and the + * start_active_frame. + * + * This is expected to be called on qh's that weren't previously actively + * running. It just picks the next frame that we can fit into without any + * thought about the past. + * + * @hsotg: The HCD state structure for the DWC OTG controller + * @qh: QH for a periodic endpoint + * + */ +static void dwc2_pick_first_frame(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) +{ + u16 frame_number; + u16 earliest_frame; + u16 next_active_frame; + u16 interval; + + /* + * Use the real frame number rather than the cached value as of the + * last SOF to give us a little extra slop. + */ + frame_number = dwc2_hcd_get_frame_number(hsotg); + + /* + * We wouldn't want to start any earlier than the next frame just in + * case the frame number ticks as we're doing this calculation. + * + * NOTE: if we could quantify how long till we actually get scheduled + * we might be able to avoid the "+ 1" by looking at the upper part of + * HFNUM (the FRREM field). For now we'll just use the + 1 though. + */ + earliest_frame = dwc2_frame_num_inc(frame_number, 1); + next_active_frame = earliest_frame; + + /* Get the "no microframe schduler" out of the way... */ + if (hsotg->core_params->uframe_sched <= 0) { + if (qh->do_split) + /* Splits are active at microframe 0 minus 1 */ + next_active_frame |= 0x7; + goto exit; + } + + /* Adjust interval as per high speed schedule which has 8 uFrame */ + interval = gcd(qh->host_interval, 8); + + /* + * We know interval must divide (HFNUM_MAX_FRNUM + 1) now that we've + * done the gcd(), so it's safe to move to the beginning of the current + * interval like this. + * + * After this we might be before earliest_frame, but don't worry, + * we'll fix it... + */ + next_active_frame = (next_active_frame / interval) * interval; + + /* + * Actually choose to start at the frame number we've been + * scheduled for. + */ + next_active_frame = dwc2_frame_num_inc(next_active_frame, + qh->assigned_uframe); + + /* + * We actually need 1 frame before since the next_active_frame is + * the frame number we'll be put on the ready list and we won't be on + * the bus until 1 frame later. + */ + next_active_frame = dwc2_frame_num_dec(next_active_frame, 1); + + /* + * By now we might actually be before the earliest_frame. Let's move + * up intervals until we're not. + */ + while (dwc2_frame_num_gt(earliest_frame, next_active_frame)) + next_active_frame = dwc2_frame_num_inc(next_active_frame, + interval); + +exit: + qh->next_active_frame = next_active_frame; + qh->start_active_frame = next_active_frame; + + dwc2_sch_vdbg(hsotg, "QH=%p First fn=%04x nxt=%04x\n", + qh, frame_number, qh->next_active_frame); +} + +/** * dwc2_do_reserve() - Make a periodic reservation * * Try to allocate space in the periodic schedule. Depending on parameters @@ -260,25 +351,9 @@ static int dwc2_do_reserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) int status; if (hsotg->core_params->uframe_sched > 0) { - int frame = -1; - status = dwc2_find_uframe(hsotg, qh); - if (status == 0) - frame = 7; - else if (status > 0) - frame = status - 1; - - /* Set the new frame up */ - if (frame >= 0) { - qh->next_active_frame &= ~0x7; - qh->next_active_frame |= (frame & 7); - dwc2_sch_dbg(hsotg, - "QH=%p sched_p nxt=%04x, uf=%d\n", - qh, qh->next_active_frame, frame); - } - - if (status > 0) - status = 0; + if (status >= 0) + qh->assigned_uframe = status; } else { status = dwc2_periodic_channel_available(hsotg); if (status) { @@ -305,6 +380,8 @@ static int dwc2_do_reserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) /* Update claimed usecs per (micro)frame */ hsotg->periodic_usecs += qh->host_us; + dwc2_pick_first_frame(hsotg, qh); + return 0; } @@ -460,6 +537,16 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) status = dwc2_do_reserve(hsotg, qh); if (status) return status; + } else { + /* + * It might have been a while, so make sure that frame_number + * is still good. Note: we could also try to use the similar + * dwc2_next_periodic_start() but that schedules much more + * tightly and we might need to hurry and queue things up. + */ + if (dwc2_frame_num_le(qh->next_active_frame, + hsotg->frame_number)) + dwc2_pick_first_frame(hsotg, qh); } qh->unreserve_pending = 0; @@ -520,7 +607,6 @@ static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg, * @urb: Holds the information about the device/endpoint needed to initialize * the QH */ -#define SCHEDULE_SLOP 10 static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, struct dwc2_hcd_urb *urb) { @@ -569,11 +655,6 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, qh->ep_type == USB_ENDPOINT_XFER_ISOC, bytecount)); - /* Ensure frame_number corresponds to the reality */ - hsotg->frame_number = dwc2_hcd_get_frame_number(hsotg); - /* Start in a slightly future (micro)frame */ - qh->next_active_frame = dwc2_frame_num_inc(hsotg->frame_number, - SCHEDULE_SLOP); qh->host_interval = urb->interval; dwc2_sch_dbg(hsotg, "QH=%p init nxt=%04x, fn=%04x, int=%#x\n", qh, qh->next_active_frame, hsotg->frame_number, @@ -589,8 +670,6 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, (dev_speed == USB_SPEED_LOW || dev_speed == USB_SPEED_FULL)) { qh->host_interval *= 8; - qh->next_active_frame |= 0x7; - qh->start_split_frame = qh->next_active_frame; dwc2_sch_dbg(hsotg, "QH=%p init*8 nxt=%04x, fn=%04x, int=%#x\n", qh, qh->next_active_frame, @@ -738,22 +817,12 @@ int dwc2_hcd_qh_add(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) /* QH already in a schedule */ return 0; - if (!dwc2_frame_num_le(qh->next_active_frame, hsotg->frame_number) && - !hsotg->frame_number) { - u16 new_frame; - - dev_dbg(hsotg->dev, - "reset frame number counter\n"); - new_frame = dwc2_frame_num_inc(hsotg->frame_number, - SCHEDULE_SLOP); - - dwc2_sch_vdbg(hsotg, "QH=%p reset nxt=%04x=>%04x\n", - qh, qh->next_active_frame, new_frame); - qh->next_active_frame = new_frame; - } - /* Add the new QH to the appropriate schedule */ if (dwc2_qh_is_non_per(qh)) { + /* Schedule right away */ + qh->start_active_frame = hsotg->frame_number; + qh->next_active_frame = qh->start_active_frame; + /* Always start in inactive schedule */ list_add_tail(&qh->qh_list_entry, &hsotg->non_periodic_sched_inactive); @@ -807,46 +876,145 @@ void dwc2_hcd_qh_unlink(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) } } -/* - * Schedule the next continuing periodic split transfer +/** + * dwc2_next_for_periodic_split() - Set next_active_frame midway thru a split. + * + * This is called for setting next_active_frame for periodic splits for all but + * the first packet of the split. Confusing? I thought so... + * + * Periodic splits are single low/full speed transfers that we end up splitting + * up into several high speed transfers. They always fit into one full (1 ms) + * frame but might be split over several microframes (125 us each). We to put + * each of the parts on a very specific high speed frame. + * + * This function figures out where the next active uFrame needs to be. + * + * @hsotg: The HCD state structure + * @qh: QH for the periodic transfer. + * @frame_number: The current frame number. + * + * Return: number missed by (or 0 if we didn't miss). */ -static void dwc2_sched_periodic_split(struct dwc2_hsotg *hsotg, - struct dwc2_qh *qh, u16 frame_number, - int sched_next_periodic_split) +static int dwc2_next_for_periodic_split(struct dwc2_hsotg *hsotg, + struct dwc2_qh *qh, u16 frame_number) { - u16 incr; u16 old_frame = qh->next_active_frame; + u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1); + int missed = 0; + u16 incr; + + /* + * Basically: increment 1 normally, but 2 right after the start split + * (except for ISOC out). + */ + if (old_frame == qh->start_active_frame && + !(qh->ep_type == USB_ENDPOINT_XFER_ISOC && !qh->ep_is_in)) + incr = 2; + else + incr = 1; + + qh->next_active_frame = dwc2_frame_num_inc(old_frame, incr); - if (sched_next_periodic_split) { + /* + * Note that it's OK for frame_number to be 1 frame past + * next_active_frame. Remember that next_active_frame is supposed to + * be 1 frame _before_ when we want to be scheduled. If we're 1 frame + * past it just means schedule ASAP. + * + * It's _not_ OK, however, if we're more than one frame past. + */ + if (dwc2_frame_num_gt(prev_frame_number, qh->next_active_frame)) { + /* + * OOPS, we missed. That's actually pretty bad since + * the hub will be unhappy; try ASAP I guess. + */ + missed = dwc2_frame_num_dec(prev_frame_number, + qh->next_active_frame); qh->next_active_frame = frame_number; - incr = dwc2_frame_num_inc(qh->start_split_frame, 1); - if (dwc2_frame_num_le(frame_number, incr)) { - /* - * Allow one frame to elapse after start split - * microframe before scheduling complete split, but - * DON'T if we are doing the next start split in the - * same frame for an ISOC out - */ - if (qh->ep_type != USB_ENDPOINT_XFER_ISOC || - qh->ep_is_in != 0) { - qh->next_active_frame = dwc2_frame_num_inc( - qh->next_active_frame, 1); - } - } - } else { - qh->next_active_frame = - dwc2_frame_num_inc(qh->start_split_frame, - qh->host_interval); - if (dwc2_frame_num_le(qh->next_active_frame, frame_number)) - qh->next_active_frame = frame_number; - qh->next_active_frame |= 0x7; - qh->start_split_frame = qh->next_active_frame; } - dwc2_sch_vdbg(hsotg, "QH=%p next(%d) fn=%04x, nxt=%04x=>%04x (%+d)\n", - qh, sched_next_periodic_split, frame_number, old_frame, - qh->next_active_frame, - dwc2_frame_num_dec(qh->next_active_frame, old_frame)); + return missed; +} + +/** + * dwc2_next_periodic_start() - Set next_active_frame for next transfer start + * + * This is called for setting next_active_frame for a periodic transfer for + * all cases other than midway through a periodic split. This will also update + * start_active_frame. + * + * Since we _always_ keep start_active_frame as the start of the previous + * transfer this is normally pretty easy: we just add our interval to + * start_active_frame and we've got our answer. + * + * The tricks come into play if we miss. In that case we'll look for the next + * slot we can fit into. + * + * @hsotg: The HCD state structure + * @qh: QH for the periodic transfer. + * @frame_number: The current frame number. + * + * Return: number missed by (or 0 if we didn't miss). + */ +static int dwc2_next_periodic_start(struct dwc2_hsotg *hsotg, + struct dwc2_qh *qh, u16 frame_number) +{ + int missed = 0; + u16 interval = qh->host_interval; + u16 prev_frame_number = dwc2_frame_num_dec(frame_number, 1); + + qh->start_active_frame = dwc2_frame_num_inc(qh->start_active_frame, + interval); + + /* + * The dwc2_frame_num_gt() function used below won't work terribly well + * with if we just incremented by a really large intervals since the + * frame counter only goes to 0x3fff. It's terribly unlikely that we + * will have missed in this case anyway. Just go to exit. If we want + * to try to do better we'll need to keep track of a bigger counter + * somewhere in the driver and handle overflows. + */ + if (interval >= 0x1000) + goto exit; + + /* + * Test for misses, which is when it's too late to schedule. + * + * A few things to note: + * - We compare against prev_frame_number since start_active_frame + * and next_active_frame are always 1 frame before we want things + * to be active and we assume we can still get scheduled in the + * current frame number. + * - Some misses are expected. Specifically, in order to work + * perfectly dwc2 really needs quite spectacular interrupt latency + * requirements. It needs to be able to handle its interrupts + * completely within 125 us of them being asserted. That not only + * means that the dwc2 interrupt handler needs to be fast but it + * means that nothing else in the system has to block dwc2 for a long + * time. We can help with the dwc2 parts of this, but it's hard to + * guarantee that a system will have interrupt latency < 125 us, so + * we have to be robust to some misses. + */ + if (dwc2_frame_num_gt(prev_frame_number, qh->start_active_frame)) { + u16 ideal_start = qh->start_active_frame; + + /* Adjust interval as per gcd with plan length. */ + interval = gcd(interval, 8); + + do { + qh->start_active_frame = dwc2_frame_num_inc( + qh->start_active_frame, interval); + } while (dwc2_frame_num_gt(prev_frame_number, + qh->start_active_frame)); + + missed = dwc2_frame_num_dec(qh->start_active_frame, + ideal_start); + } + +exit: + qh->next_active_frame = qh->start_active_frame; + + return missed; } /* @@ -865,7 +1033,9 @@ static void dwc2_sched_periodic_split(struct dwc2_hsotg *hsotg, void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, int sched_next_periodic_split) { + u16 old_frame = qh->next_active_frame; u16 frame_number; + int missed; if (dbg_qh(qh)) dev_vdbg(hsotg->dev, "%s()\n", __func__); @@ -878,30 +1048,39 @@ void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, return; } + /* + * Use the real frame number rather than the cached value as of the + * last SOF just to get us a little closer to reality. Note that + * means we don't actually know if we've already handled the SOF + * interrupt for this frame. + */ frame_number = dwc2_hcd_get_frame_number(hsotg); - if (qh->do_split) { - dwc2_sched_periodic_split(hsotg, qh, frame_number, - sched_next_periodic_split); - } else { - qh->next_active_frame = dwc2_frame_num_inc( - qh->next_active_frame, qh->host_interval); - if (dwc2_frame_num_le(qh->next_active_frame, frame_number)) - qh->next_active_frame = frame_number; - } + if (sched_next_periodic_split) + missed = dwc2_next_for_periodic_split(hsotg, qh, frame_number); + else + missed = dwc2_next_periodic_start(hsotg, qh, frame_number); + + dwc2_sch_vdbg(hsotg, + "QH=%p next(%d) fn=%04x, sch=%04x=>%04x (%+d) miss=%d %s\n", + qh, sched_next_periodic_split, frame_number, old_frame, + qh->next_active_frame, + dwc2_frame_num_dec(qh->next_active_frame, old_frame), + missed, missed ? "MISS" : ""); if (list_empty(&qh->qtd_list)) { dwc2_hcd_qh_unlink(hsotg, qh); return; } + /* * Remove from periodic_sched_queued and move to * appropriate queue + * + * Note: we purposely use the frame_number from the "hsotg" structure + * since we know SOF interrupt will handle future frames. */ - if ((hsotg->core_params->uframe_sched > 0 && - dwc2_frame_num_le(qh->next_active_frame, frame_number)) || - (hsotg->core_params->uframe_sched <= 0 && - qh->next_active_frame == frame_number)) + if (dwc2_frame_num_le(qh->next_active_frame, hsotg->frame_number)) list_move_tail(&qh->qh_list_entry, &hsotg->periodic_sched_ready); else |