From c4233573f6ee611033faa9116fc7003775a450b9 Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Thu, 12 May 2016 14:08:34 +0300 Subject: [PATCH] usb: dwc3: gadget: prepare TRBs on update transfers too If we're updating transfers, we can also prepare as many TRBs as we can fit in the ring. Let's start doing that. This patch 'solves' a limitation of how many TRBs we can prepare when we're getting close the end of the ring. Instead driver to prepare only up to end of the ring, we check if we have space to wrap around the ring properly. Note that this only happens when our enqueue and dequeue pointers are equal (which is the case for bulk endpoints after an XferComplete event). Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/gadget.c | 50 +++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 21 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index ae55f500cdbd..236c231114df 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -880,16 +880,40 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep, trace_dwc3_prepare_trb(dep, trb); } +static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep) +{ + struct dwc3_trb *tmp; + + /* + * If enqueue & dequeue are equal than it is either full or empty. + * + * One way to know for sure is if the TRB right before us has HWO bit + * set or not. If it has, then we're definitely full and can't fit any + * 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; + } + + return DWC3_TRB_NUM - 1; + } + + return dep->trb_dequeue - dep->trb_enqueue; +} + /* * dwc3_prepare_trbs - setup TRBs from requests * @dep: endpoint for which requests are being prepared - * @starting: true if the endpoint is idle and no requests are queued. * * The function goes through the requests list and sets up TRBs for the * transfers. The function returns once there are no more TRBs available or * it runs out of requests. */ -static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting) +static void dwc3_prepare_trbs(struct dwc3_ep *dep) { struct dwc3_request *req, *n; u32 trbs_left; @@ -897,23 +921,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting) BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM); - trbs_left = dep->trb_dequeue - dep->trb_enqueue; - - /* - * If enqueue & dequeue are equal than it is either full or empty. If we - * are starting to process requests then we are empty. Otherwise we are - * full and don't do anything - */ - if (!trbs_left) { - if (!starting) - return; - - trbs_left = DWC3_TRB_NUM; - } - - /* The last TRB is a link TRB, not used for xfer */ - if (trbs_left <= 1) - return; + trbs_left = dwc3_calc_trbs_left(dep); list_for_each_entry_safe(req, n, &dep->pending_list, list) { unsigned length; @@ -996,12 +1004,12 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param, */ if (start_new) { if (list_empty(&dep->started_list)) - dwc3_prepare_trbs(dep, start_new); + dwc3_prepare_trbs(dep); /* req points to the first request which will be sent */ req = next_request(&dep->started_list); } else { - dwc3_prepare_trbs(dep, start_new); + dwc3_prepare_trbs(dep); /* * req points to the first request where HWO changed from 0 to 1 -- 2.20.1