From patchwork Tue Sep 12 10:44:22 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Peter Ujfalusi X-Patchwork-Id: 812764 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.infradead.org (client-ip=65.50.211.133; helo=bombadil.infradead.org; envelope-from=linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="AnWZJI8e"; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=ti.com header.i=@ti.com header.b="ieo5D2BP"; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3xs1gH1fjSz9s7g for ; 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Tue, 12 Sep 2017 05:44:33 -0500 Received: from dlep32.itg.ti.com (157.170.170.100) by DLEE112.ent.ti.com (157.170.170.23) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.845.34 via Frontend Transport; Tue, 12 Sep 2017 05:44:33 -0500 Received: from feketebors.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep32.itg.ti.com (8.14.3/8.13.8) with ESMTP id v8CAiOu4007788; Tue, 12 Sep 2017 05:44:31 -0500 From: Peter Ujfalusi To: , Subject: [PATCH 3/5] dmaengine: Support for querying maximum trasnfer length (of an SG element) Date: Tue, 12 Sep 2017 13:44:22 +0300 Message-ID: <20170912104424.18495-4-peter.ujfalusi@ti.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170912104424.18495-1-peter.ujfalusi@ti.com> References: <20170912104424.18495-1-peter.ujfalusi@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170912_034455_545181_6C38262C X-CRM114-Status: GOOD ( 10.49 ) X-Spam-Score: -2.0 (--) X-Spam-Report: SpamAssassin version 3.4.1 on bombadil.infradead.org summary: Content analysis details: (-2.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [198.47.27.80 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dmaengine@vger.kernel.org, t-kristo@ti.com, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org Certain DMA engines have limitation on the maximum size of a transfer they can support. This size limitation is per SG element or for period length in cyclic transfers. In TI's eDMA and sDMA this limitation is not really a length limit, but it is the number of bursts that we can support in one transfer. With this callback the DMA drivers can provide hints to clients on how they should set up their buffers (sglist, cyclic buffer). Without this the clients must have open coded workarounds in place for each and every DMA engine they might be interfacing with to have correct length for the transfers. Signed-off-by: Peter Ujfalusi --- include/linux/dmaengine.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 8319101170fc..739824b94c1b 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -705,6 +705,9 @@ struct dma_filter { * @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst address * @device_config: Pushes a new configuration to a channel, return 0 or an error * code + * @device_get_max_len: Get the maximum supported length in bytes of a slave + * transfer based on the set dma_slave_config. The length limitation + * applies to each SG element's length. * @device_pause: Pauses any transfer happening on a channel. Returns * 0 or an error code * @device_resume: Resumes any transfer on a channel previously @@ -792,6 +795,8 @@ struct dma_device { int (*device_config)(struct dma_chan *chan, struct dma_slave_config *config); + u32 (*device_get_max_len)(struct dma_chan *chan, + enum dma_transfer_direction dir); int (*device_pause)(struct dma_chan *chan); int (*device_resume)(struct dma_chan *chan); int (*device_terminate_all)(struct dma_chan *chan); @@ -812,6 +817,15 @@ static inline int dmaengine_slave_config(struct dma_chan *chan, return -ENOSYS; } +static inline u32 dmaengine_slave_get_max_len(struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + if (chan->device->device_get_max_len) + return chan->device->device_get_max_len(chan, dir); + + return 0; +} + static inline bool is_slave_direction(enum dma_transfer_direction direction) { return (direction == DMA_MEM_TO_DEV) || (direction == DMA_DEV_TO_MEM);