diff options
| -rw-r--r-- | drivers/usb/dwc2/core.h | 1 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd.c | 7 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd.h | 9 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd_intr.c | 20 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd_queue.c | 81 |
5 files changed, 114 insertions, 4 deletions
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h index f22f2e9d0759..2ed3b01f7d5b 100644 --- a/drivers/usb/dwc2/core.h +++ b/drivers/usb/dwc2/core.h @@ -968,6 +968,7 @@ struct dwc2_hsotg { } flags; struct list_head non_periodic_sched_inactive; + struct list_head non_periodic_sched_waiting; struct list_head non_periodic_sched_active; struct list_head *non_periodic_qh_ptr; struct list_head periodic_sched_inactive; diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index 7b6eb0ad513b..a5d72fcd1603 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -659,6 +659,10 @@ static void dwc2_dump_channel_info(struct dwc2_hsotg *hsotg, list_for_each_entry(qh, &hsotg->non_periodic_sched_inactive, qh_list_entry) dev_dbg(hsotg->dev, " %p\n", qh); + dev_dbg(hsotg->dev, " NP waiting sched:\n"); + list_for_each_entry(qh, &hsotg->non_periodic_sched_waiting, + qh_list_entry) + dev_dbg(hsotg->dev, " %p\n", qh); dev_dbg(hsotg->dev, " NP active sched:\n"); list_for_each_entry(qh, &hsotg->non_periodic_sched_active, qh_list_entry) @@ -1818,6 +1822,7 @@ static void dwc2_qh_list_free(struct dwc2_hsotg *hsotg, static void dwc2_kill_all_urbs(struct dwc2_hsotg *hsotg) { dwc2_kill_urbs_in_qh_list(hsotg, &hsotg->non_periodic_sched_inactive); + dwc2_kill_urbs_in_qh_list(hsotg, &hsotg->non_periodic_sched_waiting); dwc2_kill_urbs_in_qh_list(hsotg, &hsotg->non_periodic_sched_active); dwc2_kill_urbs_in_qh_list(hsotg, &hsotg->periodic_sched_inactive); dwc2_kill_urbs_in_qh_list(hsotg, &hsotg->periodic_sched_ready); @@ -4998,6 +5003,7 @@ static void dwc2_hcd_free(struct dwc2_hsotg *hsotg) /* Free memory for QH/QTD lists */ dwc2_qh_list_free(hsotg, &hsotg->non_periodic_sched_inactive); + dwc2_qh_list_free(hsotg, &hsotg->non_periodic_sched_waiting); dwc2_qh_list_free(hsotg, &hsotg->non_periodic_sched_active); dwc2_qh_list_free(hsotg, &hsotg->periodic_sched_inactive); dwc2_qh_list_free(hsotg, &hsotg->periodic_sched_ready); @@ -5159,6 +5165,7 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg) /* Initialize the non-periodic schedule */ INIT_LIST_HEAD(&hsotg->non_periodic_sched_inactive); + INIT_LIST_HEAD(&hsotg->non_periodic_sched_waiting); INIT_LIST_HEAD(&hsotg->non_periodic_sched_active); /* Initialize the periodic schedule */ diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h index 78e9e01051b5..ad60e46e66e1 100644 --- a/drivers/usb/dwc2/hcd.h +++ b/drivers/usb/dwc2/hcd.h @@ -314,12 +314,16 @@ struct dwc2_hs_transfer_time { * descriptor and indicates original XferSize value for the * descriptor * @unreserve_timer: Timer for releasing periodic reservation. + * @wait_timer: Timer used to wait before re-queuing. * @dwc2_tt: Pointer to our tt info (or NULL if no tt). * @ttport: Port number within our tt. * @tt_buffer_dirty True if clear_tt_buffer_complete is pending * @unreserve_pending: True if we planned to unreserve but haven't yet. * @schedule_low_speed: True if we have a low/full speed component (either the * host is in low/full speed mode or do_split). + * @want_wait: We should wait before re-queuing; only matters for non- + * periodic transfers and is ignored for periodic ones. + * @wait_timer_cancel: Set to true to cancel the wait_timer. * * A Queue Head (QH) holds the static characteristics of an endpoint and * maintains a list of transfers (QTDs) for that endpoint. A QH structure may @@ -354,11 +358,14 @@ struct dwc2_qh { u32 desc_list_sz; u32 *n_bytes; struct timer_list unreserve_timer; + struct timer_list wait_timer; struct dwc2_tt *dwc_tt; int ttport; unsigned tt_buffer_dirty:1; unsigned unreserve_pending:1; unsigned schedule_low_speed:1; + unsigned want_wait:1; + unsigned wait_timer_cancel:1; }; /** @@ -389,6 +396,7 @@ struct dwc2_qh { * @n_desc: Number of DMA descriptors for this QTD * @isoc_frame_index_last: Last activated frame (packet) index, used in * descriptor DMA mode only + * @num_naks: Number of NAKs received on this QTD. * @urb: URB for this transfer * @qh: Queue head for this QTD * @qtd_list_entry: For linking to the QH's list of QTDs @@ -419,6 +427,7 @@ struct dwc2_qtd { u8 error_count; u8 n_desc; u16 isoc_frame_index_last; + u16 num_naks; struct dwc2_hcd_urb *urb; struct dwc2_qh *qh; struct list_head qtd_list_entry; diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c index 916d991b96b8..a5dfd9d8bd9a 100644 --- a/drivers/usb/dwc2/hcd_intr.c +++ b/drivers/usb/dwc2/hcd_intr.c @@ -53,6 +53,12 @@ #include "core.h" #include "hcd.h" +/* + * If we get this many NAKs on a split transaction we'll slow down + * retransmission. A 1 here means delay after the first NAK. + */ +#define DWC2_NAKS_BEFORE_DELAY 3 + /* This function is for debug only */ static void dwc2_track_missed_sofs(struct dwc2_hsotg *hsotg) { @@ -1201,11 +1207,25 @@ static void dwc2_hc_nak_intr(struct dwc2_hsotg *hsotg, /* * Handle NAK for IN/OUT SSPLIT/CSPLIT transfers, bulk, control, and * interrupt. Re-start the SSPLIT transfer. + * + * Normally for non-periodic transfers we'll retry right away, but to + * avoid interrupt storms we'll wait before retrying if we've got + * several NAKs. If we didn't do this we'd retry directly from the + * interrupt handler and could end up quickly getting another + * interrupt (another NAK), which we'd retry. + * + * Note that in DMA mode software only gets involved to re-send NAKed + * transfers for split transactions, so we only need to apply this + * delaying logic when handling splits. In non-DMA mode presumably we + * might want a similar delay if someone can demonstrate this problem + * affects that code path too. */ if (chan->do_split) { if (chan->complete_split) qtd->error_count = 0; qtd->complete_split = 0; + qtd->num_naks++; + qtd->qh->want_wait = qtd->num_naks >= DWC2_NAKS_BEFORE_DELAY; dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NAK); goto handle_nak_done; } diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c index fcd1676c7f0b..e34ad5e65350 100644 --- a/drivers/usb/dwc2/hcd_queue.c +++ b/drivers/usb/dwc2/hcd_queue.c @@ -58,6 +58,9 @@ /* Wait this long before releasing periodic reservation */ #define DWC2_UNRESERVE_DELAY (msecs_to_jiffies(5)) +/* If we get a NAK, wait this long before retrying */ +#define DWC2_RETRY_WAIT_DELAY (msecs_to_jiffies(1)) + /** * dwc2_periodic_channel_available() - Checks that a channel is available for a * periodic transfer @@ -1441,6 +1444,55 @@ static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg, } /** + * dwc2_wait_timer_fn() - Timer function to re-queue after waiting + * + * As per the spec, a NAK indicates that "a function is temporarily unable to + * transmit or receive data, but will eventually be able to do so without need + * of host intervention". + * + * That means that when we encounter a NAK we're supposed to retry. + * + * ...but if we retry right away (from the interrupt handler that saw the NAK) + * then we can end up with an interrupt storm (if the other side keeps NAKing + * us) because on slow enough CPUs it could take us longer to get out of the + * interrupt routine than it takes for the device to send another NAK. That + * leads to a constant stream of NAK interrupts and the CPU locks. + * + * ...so instead of retrying right away in the case of a NAK we'll set a timer + * to retry some time later. This function handles that timer and moves the + * qh back to the "inactive" list, then queues transactions. + * + * @t: Pointer to wait_timer in a qh. + */ +static void dwc2_wait_timer_fn(struct timer_list *t) +{ + struct dwc2_qh *qh = from_timer(qh, t, wait_timer); + struct dwc2_hsotg *hsotg = qh->hsotg; + unsigned long flags; + + spin_lock_irqsave(&hsotg->lock, flags); + + /* + * We'll set wait_timer_cancel to true if we want to cancel this + * operation in dwc2_hcd_qh_unlink(). + */ + if (!qh->wait_timer_cancel) { + enum dwc2_transaction_type tr_type; + + qh->want_wait = false; + + list_move(&qh->qh_list_entry, + &hsotg->non_periodic_sched_inactive); + + tr_type = dwc2_hcd_select_transactions(hsotg); + if (tr_type != DWC2_TRANSACTION_NONE) + dwc2_hcd_queue_transactions(hsotg, tr_type); + } + + spin_unlock_irqrestore(&hsotg->lock, flags); +} + +/** * dwc2_qh_init() - Initializes a QH structure * * @hsotg: The HCD state structure for the DWC OTG controller @@ -1468,6 +1520,7 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, /* Initialize QH */ qh->hsotg = hsotg; timer_setup(&qh->unreserve_timer, dwc2_unreserve_timer_fn, 0); + timer_setup(&qh->wait_timer, dwc2_wait_timer_fn, 0); qh->ep_type = ep_type; qh->ep_is_in = ep_is_in; @@ -1628,6 +1681,16 @@ void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) dwc2_do_unreserve(hsotg, qh); spin_unlock_irqrestore(&hsotg->lock, flags); } + + /* + * We don't have the lock so we can safely wait until the wait timer + * finishes. Of course, at this point in time we'd better have set + * wait_timer_active to false so if this timer was still pending it + * won't do anything anyway, but we want it to finish before we free + * memory. + */ + del_timer_sync(&qh->wait_timer); + dwc2_host_put_tt_info(hsotg, qh->dwc_tt); if (qh->desc_list) @@ -1663,9 +1726,16 @@ int dwc2_hcd_qh_add(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) 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); + if (qh->want_wait) { + list_add_tail(&qh->qh_list_entry, + &hsotg->non_periodic_sched_waiting); + qh->wait_timer_cancel = false; + mod_timer(&qh->wait_timer, + jiffies + DWC2_RETRY_WAIT_DELAY + 1); + } else { + list_add_tail(&qh->qh_list_entry, + &hsotg->non_periodic_sched_inactive); + } return 0; } @@ -1695,6 +1765,9 @@ void dwc2_hcd_qh_unlink(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) dev_vdbg(hsotg->dev, "%s()\n", __func__); + /* If the wait_timer is pending, this will stop it from acting */ + qh->wait_timer_cancel = true; + if (list_empty(&qh->qh_list_entry)) /* QH is not in a schedule */ return; @@ -1903,7 +1976,7 @@ void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, if (dwc2_qh_is_non_per(qh)) { dwc2_hcd_qh_unlink(hsotg, qh); if (!list_empty(&qh->qtd_list)) - /* Add back to inactive non-periodic schedule */ + /* Add back to inactive/waiting non-periodic schedule */ dwc2_hcd_qh_add(hsotg, qh); return; } |