Re: [PATCH v3 6/8] usb: dwc2: host: Assume all devices are on one single_tt hub

From: Felipe Balbi
Date: Thu Nov 19 2015 - 10:34:58 EST



Hi,

Douglas Anderson <dianders@xxxxxxxxxxxx> writes:
> Until we have logic to determine which devices share the same TT let's
> add logic to assume that all devices on a given dwc2 controller are on
> one single_tt hub. This is better than the previous code that assumed
> that all devices were on one multi_tt hub, since single_tt hubs
> appear (in my experience) to be much more common and any schedule that
> would work on a single_tt hub will also work on a multi_tt hub. This
> will prevent more than 8 total low/full speed devices to be on the bus
> at one time, but that's a reasonable restriction until we've made things
> smarter.
>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> Changes in v3:
> - Assuming single_tt is new for v3; not terribly well tested (yet).
>
> Changes in v2: None
>
> drivers/usb/dwc2/core.h | 1 +
> drivers/usb/dwc2/hcd_queue.c | 40 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 567ee2c9e69f..09aa2b5ae29e 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -782,6 +782,7 @@ struct dwc2_hsotg {
> u16 periodic_usecs;
> unsigned long periodic_bitmap[DIV_ROUND_UP(TOTAL_PERIODIC_USEC,
> BITS_PER_LONG)];
> + bool has_split[8];

why don't you use a u8 instead then just set each bit for each
"has_split" you need to take care of. This array is kinda ugly.

> @@ -386,6 +409,13 @@ static int dwc2_find_multi_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
> bitmap_set(hsotg->periodic_bitmap, start, qh->usecs);
> qh->start_usecs = start;
>
> + if (qh->do_split) {
> + for (i = start / EARLY_FRAME_USEC;
> + i < DIV_ROUND_UP(start + utime - 1, EARLY_FRAME_USEC);
> + i++)
> + hsotg->has_split[i] = true;

hsotg->has_split |= BIT(i);

> @@ -546,6 +577,13 @@ static void dwc2_deschedule_periodic(struct dwc2_hsotg *hsotg,
> }
>
> bitmap_clear(hsotg->periodic_bitmap, start, utime);
> +
> + if (qh->do_split) {
> + for (i = start / EARLY_FRAME_USEC;
> + i < DIV_ROUND_UP(start + utime - 1, EARLY_FRAME_USEC);
> + i++)
> + hsotg->has_split[i] = false;

hsotg->has_split &= ~BIT(i);

--
balbi

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