Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752807Ab1DSF3t (ORCPT ); Tue, 19 Apr 2011 01:29:49 -0400 Received: from eu1sys200aog106.obsmtp.com ([207.126.144.121]:40557 "EHLO eu1sys200aog106.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631Ab1DSF3r (ORCPT ); Tue, 19 Apr 2011 01:29:47 -0400 Message-ID: <4DAD1DA5.7010801@st.com> Date: Tue, 19 Apr 2011 10:59:09 +0530 From: viresh kumar User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: Linus Walleij Cc: "linux-kernel@vger.kernel.org" , Vinod Koul , Dan Williams , "linux-arm-kernel@lists.infradead.org" , amitgoel , Armando VISCONTI , Shiraz HASHIM , "linux-serial@vger.kernel.org" , "viresh.linux@gmail.com" Subject: Re: [PATCH] dmaengine: implement pause and resume for dw_dmac References: <1303173092-21785-1-git-send-email-linus.walleij@linaro.org> In-Reply-To: <1303173092-21785-1-git-send-email-linus.walleij@linaro.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2123 Lines: 71 On 04/19/2011 06:01 AM, Linus Walleij wrote: > It seems that the SPEAr needs this. > > Signed-off-by: Linus Walleij Thanks for sending this. Actually i wasn't sure that disabling channel will simply pause it, and not finish the transfer. So, didn't went for this change. > --- > drivers/dma/dw_dmac.c | 22 ++++++++++++++++++++-- > drivers/dma/dw_dmac_regs.h | 1 + > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c > index 9c25c7d..60ac779 100644 > --- a/drivers/dma/dw_dmac.c > +++ b/drivers/dma/dw_dmac.c > @@ -801,8 +801,7 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, > struct dw_desc *desc, *_desc; > LIST_HEAD(list); > > - /* Only supports DMA_TERMINATE_ALL */ > - if (cmd != DMA_TERMINATE_ALL) > + if (cmd != DMA_TERMINATE_ALL && cmd != DMA_PAUSE && cmd != DMA_RESUME) > return -ENXIO; > > /* > @@ -813,11 +812,30 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, > */ > spin_lock_bh(&dwc->lock); > > + if (cmd == DMA_RESUME) { > + if (dwc->paused) { > + channel_set_bit(dw, CH_EN, dwc->mask); > + while (!dma_readl(dw, CH_EN) & dwc->mask) Probably should be written as while (!(dma_readl(dw, CH_EN) & dwc->mask)) > + cpu_relax(); > + } Should return error in else part?? > + spin_unlock_bh(&dwc->lock); > + return 0; > + } > + > channel_clear_bit(dw, CH_EN, dwc->mask); > > while (dma_readl(dw, CH_EN) & dwc->mask) > cpu_relax(); > > + if (cmd == DMA_PAUSE) { > + dwc->paused = true; > + spin_unlock_bh(&dwc->lock); I have sent another patchset in which _bh variants are replaced with irqsave variants. To remove any conflicts, i would add your patch in my patchset, with above mentioned changes keeping your authorship intact. Will that be fine?? -- viresh -- 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/