From patchwork Thu Jun 9 11:41:43 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Reichl X-Patchwork-Id: 9166771 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DDE14604DB for ; Thu, 9 Jun 2016 11:48:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CDF802833F for ; Thu, 9 Jun 2016 11:48:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C2DB328341; Thu, 9 Jun 2016 11:48:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4D5DD2833F for ; Thu, 9 Jun 2016 11:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751322AbcFILrZ (ORCPT ); Thu, 9 Jun 2016 07:47:25 -0400 Received: from mail.horus.com ([78.46.148.228]:58206 "EHLO mail.horus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751286AbcFILrY (ORCPT ); Thu, 9 Jun 2016 07:47:24 -0400 Received: from [192.168.1.20] (85-127-114-243.dynamic.xdsl-line.inode.at [85.127.114.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "E-Mail Matthias Reichl", Issuer "HiassofT CA 2014" (verified OK)) by mail.horus.com (Postfix) with ESMTPS id 68E2064092; Thu, 9 Jun 2016 13:41:45 +0200 (CEST) Received: by camel2.lan (Postfix, from userid 1000) id E846B1C7307; Thu, 9 Jun 2016 13:41:44 +0200 (CEST) From: Matthias Reichl To: Vinod Koul , Stephen Warren , Lee Jones , Eric Anholt Cc: Martin Sperl , Clive Messer , dmaengine@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] dmaengine: bcm2835: Fix cyclic DMA period splitting Date: Thu, 9 Jun 2016 13:41:43 +0200 Message-Id: <1465472504-10191-2-git-send-email-hias@horus.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1465472504-10191-1-git-send-email-hias@horus.com> References: <1465472504-10191-1-git-send-email-hias@horus.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The code responsible for splitting periods into chunks that can be handled by the DMA controller missed to update total_len, the number of bytes processed in the current period, when there are more chunks to follow. Therefore total_len was stuck at 0 and the code didn't work at all. This resulted in a wrong control block layout and audio issues because the cyclic DMA callback wasn't executing on period boundaries. Fix this by adding the missing total_len update. Signed-off-by: Matthias Reichl Signed-off-by: Martin Sperl Tested-by: Clive Messer Reviewed-by: Eric Anholt --- drivers/dma/bcm2835-dma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index 6149b27..344bcf92 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -251,8 +251,11 @@ static void bcm2835_dma_create_cb_set_length( */ /* have we filled in period_length yet? */ - if (*total_len + control_block->length < period_len) + if (*total_len + control_block->length < period_len) { + /* update number of bytes in this period so far */ + *total_len += control_block->length; return; + } /* calculate the length that remains to reach period_length */ control_block->length = period_len - *total_len;