From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754554AbcHSBAQ (ORCPT ); Thu, 18 Aug 2016 21:00:16 -0400 Received: from mail-pf0-f170.google.com ([209.85.192.170]:35866 "EHLO mail-pf0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753902AbcHSBAN (ORCPT ); Thu, 18 Aug 2016 21:00:13 -0400 From: Stephen Barber To: Vinod Koul Cc: Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, Douglas Anderson , Hsin-Yu Chao , Stephen Barber Subject: [PATCH] dmaengine: pl330: fix residual for non-running BUSY descriptors Date: Thu, 18 Aug 2016 17:59:59 -0700 Message-Id: <1471568399-35770-1-git-send-email-smbarber@chromium.org> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Only one descriptor in the work list should be running at any given time, but it's possible to have an enqueued BUSY descriptor that has not yet transferred any data, or for a BUSY descriptor to linger briefly before transitioning to DONE. These cases should be handled to keep residual calculations consistent even with the non-running BUSY descriptors in the work list. Signed-off-by: Stephen Barber --- drivers/dma/pl330.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 372b435..ff8f889 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2274,7 +2274,7 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, { enum dma_status ret; unsigned long flags; - struct dma_pl330_desc *desc, *running = NULL; + struct dma_pl330_desc *desc, *running = NULL, *last_enq = NULL; struct dma_pl330_chan *pch = to_pchan(chan); unsigned int transferred, residual = 0; @@ -2291,6 +2291,8 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, if (pch->thread->req_running != -1) running = pch->thread->req[pch->thread->req_running].desc; + last_enq = pch->thread->req[pch->thread->lstenq].desc; + /* Check in pending list */ list_for_each_entry(desc, &pch->work_list, node) { if (desc->status == DONE) @@ -2298,6 +2300,15 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, else if (running && desc == running) transferred = pl330_get_current_xferred_count(pch, desc); + else if (desc->status == BUSY) + /* + * Busy but not running means either just enqueued, + * or finished and not yet marked done + */ + if (desc == last_enq) + transferred = 0; + else + transferred = desc->bytes_requested; else transferred = 0; residual += desc->bytes_requested - transferred; -- 2.8.0.rc3.226.g39d4020