From patchwork Mon Feb 10 15:57:04 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 3620011 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 6FD6F9F382 for ; Mon, 10 Feb 2014 16:11:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 71CE620148 for ; Mon, 10 Feb 2014 16:11:16 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 83DE22013D for ; Mon, 10 Feb 2014 16:11:15 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WCtQj-0001VD-TX; Mon, 10 Feb 2014 16:09:58 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WCtG8-0000jo-Td; Mon, 10 Feb 2014 15:59:00 +0000 Received: from pandora.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WCtEd-0000UU-EE for linux-arm-kernel@lists.infradead.org; Mon, 10 Feb 2014 15:57:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora; h=Date:Sender:Message-Id:Subject:Cc:To:From:References:In-Reply-To; bh=ncVKpSRIPKw3kmuS+5BlzMN9SL5o91rC/WwDPOysfmY=; b=EAxnLz/Yxrxh87r79DYIo2exjlmuy7T5bmutsesjoiOOnIi+idC1cCcntmiqlI74qgHuub75Has2DQYcIwbYBvhqxTmUxeSr6ljSGqn0fG5dmj8QShLEa3NJGNvC5zMTKtcnS3i8F6aQoIf1GX2WYyFp6WCr8ySExCJSmVJAJGM=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:49382 helo=rmk-PC.arm.linux.org.uk) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.76) (envelope-from ) id 1WCtEH-000548-8Y; Mon, 10 Feb 2014 15:57:05 +0000 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.76) (envelope-from ) id 1WCtEG-0006Ww-Sb; Mon, 10 Feb 2014 15:57:04 +0000 In-Reply-To: <20140210155531.GB26684@n2100.arm.linux.org.uk> References: <20140210155531.GB26684@n2100.arm.linux.org.uk> From: Russell King To: dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org Subject: [PATCH 14/26] dmaengine: omap-dma: move barrier to omap_dma_start_desc() Message-Id: Date: Mon, 10 Feb 2014 15:57:04 +0000 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140210_105727_872209_7AFCCC5C X-CRM114-Status: GOOD ( 10.51 ) X-Spam-Score: -2.6 (--) Cc: Vinod Koul , Dan Williams X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We don't need to issue a barrier for every segment of a DMA transfer; doing this just once per descriptor will do. Signed-off-by: Russell King --- drivers/dma/omap-dma.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index 49609275b2e7..49b303296d75 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -195,7 +195,6 @@ static void omap_dma_start(struct omap_chan *c, struct omap_desc *d) val = c->plat->dma_read(CCR, c->dma_ch); val |= CCR_ENABLE; - mb(); c->plat->dma_write(val, CCR, c->dma_ch); } @@ -301,6 +300,13 @@ static void omap_dma_start_desc(struct omap_chan *c) c->desc = d = to_omap_dma_desc(&vd->tx); c->sgidx = 0; + /* + * This provides the necessary barrier to ensure data held in + * DMA coherent memory is visible to the DMA engine prior to + * the transfer starting. + */ + mb(); + c->plat->dma_write(d->ccr, CCR, c->dma_ch); if (dma_omap1()) c->plat->dma_write(d->ccr >> 16, CCR2, c->dma_ch);