From patchwork Thu Jul 18 16:46:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 2829731 Return-Path: X-Original-To: patchwork-linux-mmc@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 E06689F967 for ; Thu, 18 Jul 2013 16:48:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E980B201EF for ; Thu, 18 Jul 2013 16:48:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F58F201EA for ; Thu, 18 Jul 2013 16:48:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759171Ab3GRQrm (ORCPT ); Thu, 18 Jul 2013 12:47:42 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:50410 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759216Ab3GRQrj (ORCPT ); Thu, 18 Jul 2013 12:47:39 -0400 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id r6IGkpKC026553; Thu, 18 Jul 2013 11:46:51 -0500 Received: from DLEE70.ent.ti.com (dlee70.ent.ti.com [157.170.170.113]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id r6IGkoRA013431; Thu, 18 Jul 2013 11:46:50 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by DLEE70.ent.ti.com (157.170.170.113) with Microsoft SMTP Server id 14.2.342.3; Thu, 18 Jul 2013 11:46:50 -0500 Received: from joel-laptop.am.dhcp.ti.com (joel-laptop.am.dhcp.ti.com [10.247.24.76]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id r6IGkjSp021186; Thu, 18 Jul 2013 11:46:50 -0500 From: Joel Fernandes To: Tony Lindgren , Sekhar Nori , Matt Porter , Grant Likely , Rob Herring , Vinod Koul , Mark Brown , Benoit Cousson , Russell King , Balaji TK , Gururaja Hebbar , Chris Ball CC: Jason Kridner , Mark Jackson , Devicetree Discuss , Linux OMAP List , Linux ARM Kernel List , Linux DaVinci Kernel List , Linux Kernel Mailing List , Linux Documentation List , Linux MMC List , Linux SPI Devel List , Arnd Bergmann , Joel Fernandes Subject: [PATCH 1/3] dmaengine: add dma_get_slave_sg_limits() Date: Thu, 18 Jul 2013 11:46:39 -0500 Message-ID: <1374166001-31340-2-git-send-email-joelf@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1374166001-31340-1-git-send-email-joelf@ti.com> References: <1374166001-31340-1-git-send-email-joelf@ti.com> MIME-Version: 1.0 Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Spam-Status: No, score=-7.2 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 From: Matt Porter Add a dmaengine API to retrieve slave SG transfer limits. The API is optionally implemented by dmaengine drivers and when unimplemented will return a NULL pointer. A client driver using this API provides the required dma channel, address width, and burst size of the transfer. dma_get_slave_sg_limits() returns an SG limits structure with the maximum number and size of SG segments that the given channel can handle. [Joel Fernandes : Changes to allocate limits structure in client and fill up in DMAEngine implementation.] Signed-off-by: Matt Porter Signed-off-by: Joel Fernandes Cc: Mark Jackson --- include/linux/dmaengine.h | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 96d3e4a..2985878 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -371,6 +371,18 @@ struct dma_slave_config { unsigned int slave_id; }; +/* struct dma_slave_sg_limits - expose SG transfer limits of a channel + * + * @max_seg_nr: maximum number of SG segments supported on a SG/SLAVE + * channel (0 for no maximum or not a SG/SLAVE channel) + * @max_seg_len: maximum length of SG segments supported on a SG/SLAVE + * channel (0 for no maximum or not a SG/SLAVE channel) + */ +struct dma_slave_sg_limits { + u32 max_seg_nr; + u32 max_seg_len; +}; + static inline const char *dma_chan_name(struct dma_chan *chan) { return dev_name(&chan->dev->device); @@ -534,6 +546,7 @@ struct dma_tx_state { * struct with auxiliary transfer status information, otherwise the call * will just return a simple status code * @device_issue_pending: push pending transactions to hardware + * @device_slave_sg_limits: return the slave SG capabilities */ struct dma_device { @@ -602,6 +615,10 @@ struct dma_device { dma_cookie_t cookie, struct dma_tx_state *txstate); void (*device_issue_pending)(struct dma_chan *chan); + int (*device_slave_sg_limits)(struct dma_chan *chan, + enum dma_slave_buswidth addr_width, + u32 maxburst, + struct dma_slave_sg_limits *sg_limits); }; static inline int dmaengine_device_control(struct dma_chan *chan, @@ -963,6 +980,34 @@ dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used, } } +/** + * dma_get_slave_sg_limits - get DMAC SG transfer capabilities + * @chan: target DMA channel + * @addr_width: address width of the DMA transfer + * @maxburst: maximum DMA transfer burst size + * @sg_limits: point to sg_limits struct to populate with limit info + * + * Get SG transfer capabilities for a specified channel. If the dmaengine + * driver does not implement SG transfer capabilities then NULL is + * returned. + */ +static inline int +dma_get_slave_sg_limits(struct dma_chan *chan, + enum dma_slave_buswidth addr_width, + u32 maxburst, + struct dma_slave_sg_limits *sg_limits) + +{ + + if (chan->device->device_slave_sg_limits && sg_limits) + return chan->device->device_slave_sg_limits(chan, + addr_width, + maxburst, + sg_limits); + + return -EINVAL; +} + enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie); #ifdef CONFIG_DMA_ENGINE enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);