diff options
| -rw-r--r-- | drivers/usb/dwc3/gadget.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 3c4fd4854317..fbc796892f6b 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -842,6 +842,25 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep, trace_dwc3_prepare_trb(dep, trb); } +/** + * dwc3_ep_prev_trb() - Returns the previous TRB in the ring + * @dep: The endpoint with the TRB ring + * @index: The index of the current TRB in the ring + * + * Returns the TRB prior to the one pointed to by the index. If the + * index is 0, we will wrap backwards, skip the link TRB, and return + * the one just before that. + */ +static struct dwc3_trb *dwc3_ep_prev_trb(struct dwc3_ep *dep, u8 index) +{ + if (!index) + index = DWC3_TRB_NUM - 2; + else + index = dep->trb_enqueue - 1; + + return &dep->trb_pool[index]; +} + static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep) { struct dwc3_trb *tmp; @@ -855,12 +874,9 @@ static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep) * more transfers in our ring. */ if (dep->trb_enqueue == dep->trb_dequeue) { - /* If we're full, enqueue/dequeue are > 0 */ - if (dep->trb_enqueue) { - tmp = &dep->trb_pool[dep->trb_enqueue - 1]; - if (tmp->ctrl & DWC3_TRB_CTRL_HWO) - return 0; - } + tmp = dwc3_ep_prev_trb(dep, dep->trb_enqueue); + if (tmp->ctrl & DWC3_TRB_CTRL_HWO) + return 0; return DWC3_TRB_NUM - 1; } |