* 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>
return ret;
}
+/**
+ * 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
*
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) {
/* Update claimed usecs per (micro)frame */
hsotg->periodic_usecs += qh->host_us;
+ dwc2_pick_first_frame(hsotg, qh);
+
return 0;
}
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;
* @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)
{
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,
(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,
/* 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);
}
}
-/*
- * 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;
}
/*
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__);
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
projects / GitHub / LineageOS / G12 / android_kernel_amlogic_linux-4.9.git / commitdiff