From patchwork Thu Jul 23 18:39:50 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vinod Koul X-Patchwork-Id: 6855561 Return-Path: X-Original-To: patchwork-dmaengine@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 5E2AE9F1D4 for ; Thu, 23 Jul 2015 18:38:20 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 89E0020528 for ; Thu, 23 Jul 2015 18:38:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FB6F204AB for ; Thu, 23 Jul 2015 18:38:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753544AbbGWSiR (ORCPT ); Thu, 23 Jul 2015 14:38:17 -0400 Received: from mga02.intel.com ([134.134.136.20]:49503 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753635AbbGWSiP (ORCPT ); Thu, 23 Jul 2015 14:38:15 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP; 23 Jul 2015 11:38:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,532,1432623600"; d="scan'208";a="611678513" Received: from vkoul-udesk7.iind.intel.com ([10.223.84.34]) by orsmga003.jf.intel.com with ESMTP; 23 Jul 2015 11:38:05 -0700 From: Vinod Koul To: dmaengine@vger.kernel.org Cc: Robert Jarzmik , Lars-Peter Clausen , Jun Nie , Vinod Koul Subject: [PATCH 1/3] Documentation: dmaengine: fix the DMA_CTRL_ACK documentation Date: Fri, 24 Jul 2015 00:09:50 +0530 Message-Id: <1437676792-13465-1-git-send-email-vinod.koul@intel.com> X-Mailer: git-send-email 1.9.1 Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Spam-Status: No, score=-8.1 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 As discussed recently the meaning of DMA_CTRL_ACK is that a desc cannot be reused by provider until the client acknowledges receipt, i.e. has has a chance to establish any dependency chains. So update documentation Signed-off-by: Vinod Koul Acked-by: Robert Jarzmik --- Documentation/dmaengine/provider.txt | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index ca67b0f04c6e..8b8eb7c57c1f 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt @@ -345,12 +345,12 @@ where to put them) that abstracts it away. * DMA_CTRL_ACK - - If set, the transfer can be reused after being completed. - - There is a guarantee the transfer won't be freed until it is acked - by async_tx_ack(). - - As a consequence, if a device driver wants to skip the dma_map_sg() and - dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used, - it can resubmit the transfer right after its completion. + - If clear, the descriptor cannot be reused by provider untill the + client acknowledges receipt, i.e. has has a chance to establish any + dependency chains + - This can be acked by invoking async_tx_ack() + - If set, does not mean descriptor can be reused + General Design Notes --------------------