diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/dwc2/hcd.h | 6 | ||||
| -rw-r--r-- | drivers/usb/dwc2/hcd_queue.c | 237 |
2 files changed, 187 insertions, 56 deletions
diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h index 809bc4ff9116..79473ea35bd6 100644 --- a/drivers/usb/dwc2/hcd.h +++ b/drivers/usb/dwc2/hcd.h @@ -215,6 +215,7 @@ enum dwc2_transaction_type { /** * struct dwc2_qh - Software queue head structure * + * @hsotg: The HCD state structure for the DWC OTG controller * @ep_type: Endpoint type. One of the following values: * - USB_ENDPOINT_XFER_CONTROL * - USB_ENDPOINT_XFER_BULK @@ -252,13 +253,16 @@ enum dwc2_transaction_type { * @n_bytes: Xfer Bytes array. Each element corresponds to a transfer * descriptor and indicates original XferSize value for the * descriptor + * @unreserve_timer: Timer for releasing periodic reservation. * @tt_buffer_dirty True if clear_tt_buffer_complete is pending + * @unreserve_pending: True if we planned to unreserve but haven't yet. * * 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 * be entered in either the non-periodic or periodic schedule. */ struct dwc2_qh { + struct dwc2_hsotg *hsotg; u8 ep_type; u8 ep_is_in; u16 maxp; @@ -281,7 +285,9 @@ struct dwc2_qh { dma_addr_t desc_list_dma; u32 desc_list_sz; u32 *n_bytes; + struct timer_list unreserve_timer; unsigned tt_buffer_dirty:1; + unsigned unreserve_pending:1; }; /** diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c index 0e9faa75593c..b9e4867e1afd 100644 --- a/drivers/usb/dwc2/hcd_queue.c +++ b/drivers/usb/dwc2/hcd_queue.c @@ -53,6 +53,94 @@ #include "core.h" #include "hcd.h" +/* Wait this long before releasing periodic reservation */ +#define DWC2_UNRESERVE_DELAY (msecs_to_jiffies(5)) + +/** + * dwc2_do_unreserve() - Actually release the periodic reservation + * + * This function actually releases the periodic bandwidth that was reserved + * by the given qh. + * + * @hsotg: The HCD state structure for the DWC OTG controller + * @qh: QH for the periodic transfer. + */ +static void dwc2_do_unreserve(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) +{ + assert_spin_locked(&hsotg->lock); + + WARN_ON(!qh->unreserve_pending); + + /* No more unreserve pending--we're doing it */ + qh->unreserve_pending = false; + + if (WARN_ON(!list_empty(&qh->qh_list_entry))) + list_del_init(&qh->qh_list_entry); + + /* Update claimed usecs per (micro)frame */ + hsotg->periodic_usecs -= qh->usecs; + + if (hsotg->core_params->uframe_sched > 0) { + int i; + + for (i = 0; i < 8; i++) { + hsotg->frame_usecs[i] += qh->frame_usecs[i]; + qh->frame_usecs[i] = 0; + } + } else { + /* Release periodic channel reservation */ + hsotg->periodic_channels--; + } +} + +/** + * dwc2_unreserve_timer_fn() - Timer function to release periodic reservation + * + * According to the kernel doc for usb_submit_urb() (specifically the part about + * "Reserved Bandwidth Transfers"), we need to keep a reservation active as + * long as a device driver keeps submitting. Since we're using HCD_BH to give + * back the URB we need to give the driver a little bit of time before we + * release the reservation. This worker is called after the appropriate + * delay. + * + * @work: Pointer to a qh unreserve_work. + */ +static void dwc2_unreserve_timer_fn(unsigned long data) +{ + struct dwc2_qh *qh = (struct dwc2_qh *)data; + struct dwc2_hsotg *hsotg = qh->hsotg; + unsigned long flags; + + /* + * Wait for the lock, or for us to be scheduled again. We + * could be scheduled again if: + * - We started executing but didn't get the lock yet. + * - A new reservation came in, but cancel didn't take effect + * because we already started executing. + * - The timer has been kicked again. + * In that case cancel and wait for the next call. + */ + while (!spin_trylock_irqsave(&hsotg->lock, flags)) { + if (timer_pending(&qh->unreserve_timer)) + return; + } + + /* + * Might be no more unreserve pending if: + * - We started executing but didn't get the lock yet. + * - A new reservation came in, but cancel didn't take effect + * because we already started executing. + * + * We can't put this in the loop above because unreserve_pending needs + * to be accessed under lock, so we can only check it once we got the + * lock. + */ + if (qh->unreserve_pending) + dwc2_do_unreserve(hsotg, qh); + + spin_unlock_irqrestore(&hsotg->lock, flags); +} + /** * dwc2_qh_init() - Initializes a QH structure * @@ -71,6 +159,9 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh, dev_vdbg(hsotg->dev, "%s()\n", __func__); /* Initialize QH */ + qh->hsotg = hsotg; + setup_timer(&qh->unreserve_timer, dwc2_unreserve_timer_fn, + (unsigned long)qh); qh->ep_type = dwc2_hcd_get_pipe_type(&urb->pipe_info); qh->ep_is_in = dwc2_hcd_is_pipe_in(&urb->pipe_info) ? 1 : 0; @@ -240,6 +331,15 @@ struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg, */ void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) { + /* Make sure any unreserve work is finished. */ + if (del_timer_sync(&qh->unreserve_timer)) { + unsigned long flags; + + spin_lock_irqsave(&hsotg->lock, flags); + dwc2_do_unreserve(hsotg, qh); + spin_unlock_irqrestore(&hsotg->lock, flags); + } + if (qh->desc_list) dwc2_hcd_qh_free_ddma(hsotg, qh); kfree(qh); @@ -477,51 +577,74 @@ static int dwc2_schedule_periodic(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->sched_frame &= ~0x7; - qh->sched_frame |= (frame & 7); - dwc2_sch_dbg(hsotg, "QH=%p sched_p sch=%04x, uf=%d\n", - qh, qh->sched_frame, frame); + status = dwc2_check_max_xfer_size(hsotg, qh); + if (status) { + dev_dbg(hsotg->dev, + "%s: Channel max transfer size too small for periodic transfer\n", + __func__); + return status; + } + + /* Cancel pending unreserve; if canceled OK, unreserve was pending */ + if (del_timer(&qh->unreserve_timer)) + WARN_ON(!qh->unreserve_pending); + + /* + * Only need to reserve if there's not an unreserve pending, since if an + * unreserve is pending then by definition our old reservation is still + * valid. Unreserve might still be pending even if we didn't cancel if + * dwc2_unreserve_timer_fn() already started. Code in the timer handles + * that case. + */ + if (!qh->unreserve_pending) { + 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->sched_frame &= ~0x7; + qh->sched_frame |= (frame & 7); + dwc2_sch_dbg(hsotg, + "QH=%p sched_p sch=%04x, uf=%d\n", + qh, qh->sched_frame, frame); + } + + if (status > 0) + status = 0; + } else { + status = dwc2_periodic_channel_available(hsotg); + if (status) { + dev_info(hsotg->dev, + "%s: No host channel available for periodic transfer\n", + __func__); + return status; + } + + status = dwc2_check_periodic_bandwidth(hsotg, qh); } - if (status > 0) - status = 0; - } else { - status = dwc2_periodic_channel_available(hsotg); if (status) { - dev_info(hsotg->dev, - "%s: No host channel available for periodic transfer\n", - __func__); + dev_dbg(hsotg->dev, + "%s: Insufficient periodic bandwidth for periodic transfer\n", + __func__); return status; } - status = dwc2_check_periodic_bandwidth(hsotg, qh); - } + if (hsotg->core_params->uframe_sched <= 0) + /* Reserve periodic channel */ + hsotg->periodic_channels++; - if (status) { - dev_dbg(hsotg->dev, - "%s: Insufficient periodic bandwidth for periodic transfer\n", - __func__); - return status; + /* Update claimed usecs per (micro)frame */ + hsotg->periodic_usecs += qh->usecs; } - status = dwc2_check_max_xfer_size(hsotg, qh); - if (status) { - dev_dbg(hsotg->dev, - "%s: Channel max transfer size too small for periodic transfer\n", - __func__); - return status; - } + qh->unreserve_pending = 0; if (hsotg->core_params->dma_desc_enable > 0) /* Don't rely on SOF and start in ready schedule */ @@ -531,13 +654,6 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) list_add_tail(&qh->qh_list_entry, &hsotg->periodic_sched_inactive); - if (hsotg->core_params->uframe_sched <= 0) - /* Reserve periodic channel */ - hsotg->periodic_channels++; - - /* Update claimed usecs per (micro)frame */ - hsotg->periodic_usecs += qh->usecs; - return status; } @@ -551,22 +667,31 @@ static int dwc2_schedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh) { - int i; + bool did_modify; - list_del_init(&qh->qh_list_entry); + assert_spin_locked(&hsotg->lock); - /* Update claimed usecs per (micro)frame */ - hsotg->periodic_usecs -= qh->usecs; + /* + * Schedule the unreserve to happen in a little bit. Cases here: + * - Unreserve worker might be sitting there waiting to grab the lock. + * In this case it will notice it's been schedule again and will + * quit. + * - Unreserve worker might not be scheduled. + * + * We should never already be scheduled since dwc2_schedule_periodic() + * should have canceled the scheduled unreserve timer (hence the + * warning on did_modify). + * + * We add + 1 to the timer to guarantee that at least 1 jiffy has + * passed (otherwise if the jiffy counter might tick right after we + * read it and we'll get no delay). + */ + did_modify = mod_timer(&qh->unreserve_timer, + jiffies + DWC2_UNRESERVE_DELAY + 1); + WARN_ON(did_modify); + qh->unreserve_pending = 1; - if (hsotg->core_params->uframe_sched > 0) { - for (i = 0; i < 8; i++) { - hsotg->frame_usecs[i] += qh->frame_usecs[i]; - qh->frame_usecs[i] = 0; - } - } else { - /* Release periodic channel reservation */ - hsotg->periodic_channels--; - } + list_del_init(&qh->qh_list_entry); } /** |