Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756692AbbLARZl (ORCPT ); Tue, 1 Dec 2015 12:25:41 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:52273 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756663AbbLARZi (ORCPT ); Tue, 1 Dec 2015 12:25:38 -0500 Date: Tue, 1 Dec 2015 11:25:35 -0600 From: Andy Gross To: Arnd Bergmann Cc: Stanimir Varbanov , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, dmaengine@vger.kernel.org, Vinod Koul , Rob Herring , Rob Herring , Mark Rutland , Pawel Moll , Ian Campbell , Archit Taneja Subject: Re: [PATCH 3/4] dmaengine: qcom_bam_dma: use correct pipe FIFO size Message-ID: <20151201172535.GB26687@Agamemnon.attlocal.net> References: <1448961299-15161-1-git-send-email-stanimir.varbanov@linaro.org> <1448961299-15161-4-git-send-email-stanimir.varbanov@linaro.org> <1971752.Auss6gPApO@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1971752.Auss6gPApO@wuerfel> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1542 Lines: 31 On Tue, Dec 01, 2015 at 11:28:32AM +0100, Arnd Bergmann wrote: > On Tuesday 01 December 2015 11:14:58 Stanimir Varbanov wrote: > > > > diff --git a/drivers/dma/qcom_bam_dma.c b/drivers/dma/qcom_bam_dma.c > > index 0f06f3b7a72b..6d290de9ab2b 100644 > > --- a/drivers/dma/qcom_bam_dma.c > > +++ b/drivers/dma/qcom_bam_dma.c > > @@ -458,7 +458,7 @@ static void bam_chan_init_hw(struct bam_chan *bchan, > > */ > > writel_relaxed(ALIGN(bchan->fifo_phys, sizeof(struct bam_desc_hw)), > > bam_addr(bdev, bchan->id, BAM_P_DESC_FIFO_ADDR)); > > - writel_relaxed(BAM_DESC_FIFO_SIZE, > > + writel_relaxed(BAM_MAX_DATA_SIZE, > > bam_addr(bdev, bchan->id, BAM_P_FIFO_SIZES)); > > > > /* enable the per pipe interrupts, enable EOT, ERR, and INT irqs */ > > I'm looking at that now and fail to see why these have to use writel_relaxed(). At some point I believe I got a comment about using (readl/writel)_relaxed instead of readl/writel. So I used these instead. Has the wind direction changed? =) Using the readl/writel is nice w.r.t. having the implicit barriers, especially with the funky 1K boundary on reordering of operations that can occur on Kraits. This can hit you on accesses even within the same IP block. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/