From patchwork Sun Jul 21 06:58:45 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 2830902 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 C62839F4D4 for ; Sun, 21 Jul 2013 07:03:59 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CBE9B20168 for ; Sun, 21 Jul 2013 07:03:58 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CEF232013C for ; Sun, 21 Jul 2013 07:03:56 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V0nd3-00038e-2U; Sun, 21 Jul 2013 07:00:26 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1V0ncC-0006uD-CC; Sun, 21 Jul 2013 06:59:32 +0000 Received: from arroyo.ext.ti.com ([192.94.94.40]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V0nbz-0006qV-4I for linux-arm-kernel@lists.infradead.org; Sun, 21 Jul 2013 06:59:21 +0000 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id r6L6wlpE011990; Sun, 21 Jul 2013 01:58:47 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id r6L6wlm0000783; Sun, 21 Jul 2013 01:58:47 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by DFLE73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.2.342.3; Sun, 21 Jul 2013 01:58:47 -0500 Received: from joel-laptop.itg.ti.com (h56-25.vpn.ti.com [172.24.56.25]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id r6L6wjF5011880; Sun, 21 Jul 2013 01:58:46 -0500 From: Joel Fernandes To: Tony Lindgren , Sekhar Nori , Santosh Shilimkar , Sricharan R , Rajendra Nayak , Lokesh Vutla , Matt Porter , Grant Likely , Rob Herring , Vinod Koul , Dan Williams , Mark Brown , Benoit Cousson , Russell King , Arnd Bergmann , Balaji TK , Gururaja Hebbar , Chris Ball , Jason Kridner Subject: [RFC 5/5] DMA: EDMA: Leave linked to Null slot instead of DUMMY slot Date: Sun, 21 Jul 2013 01:58:45 -0500 Message-ID: <1374389925-32667-1-git-send-email-joelf@ti.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130721_025919_282362_9428916F X-CRM114-Status: GOOD ( 11.44 ) X-Spam-Score: -7.3 (-------) Cc: Linux DaVinci Kernel List , Joel Fernandes , Linux MMC List , Linux Kernel Mailing List , Linux OMAP List , Linux ARM Kernel List 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, 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 Dummy slot has been used as a way for missed-events not to be reported as missing. This has been particularly troublesome for cases where we might want to temporarily pause all incoming events. For EDMA DMAC, there is no way to do any such pausing of events as the occurence of the "next" event is not software controlled. Using "edma_pause" in IRQ handlers doesn't help as by then the event in concern from the slave is already missed. Linking a dummy slot, is seen to absorb these events which we didn't want to miss. So we don't link to dummy, but instead leave it linked to NULL set, allow an error condition and detect the channel that missed it. Signed-off-by: Joel Fernandes --- drivers/dma/edma.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index b0b5bcd..e9f1f27 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -160,9 +160,6 @@ static void edma_execute(struct edma_chan *echan) /* Link to the previous slot if not the last set */ if (i != (total_process - 1)) edma_link(echan->slot[i], echan->slot[i+1]); - /* Final pset links to the dummy pset */ - else - edma_link(echan->slot[i], echan->ecc->dummy_slot); } edesc->total_processed += total_process;