Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751545AbdILKpd (ORCPT ); Tue, 12 Sep 2017 06:45:33 -0400 Received: from lelnx193.ext.ti.com ([198.47.27.77]:26760 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751370AbdILKpC (ORCPT ); Tue, 12 Sep 2017 06:45:02 -0400 From: Peter Ujfalusi To: , CC: , , , , Subject: [PATCH 4/5] dmaengine: edma: Implement device_get_max_len callback Date: Tue, 12 Sep 2017 13:44:23 +0300 Message-ID: <20170912104424.18495-5-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 Content-Type: text/plain; charset="utf-8" X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8CAjdrd015439 Content-Length: 1710 Lines: 56 eDMA can support maximum of 65535 number of bursts in one transfer. The limitation is because the CCNT counter is 16bit unsigned. Signed-off-by: Peter Ujfalusi --- drivers/dma/edma.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 6970355abdc9..14c52574262c 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -900,6 +900,28 @@ static int edma_slave_config(struct dma_chan *chan, return 0; } +static u32 edma_get_max_len(struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + struct edma_chan *echan = to_edma_chan(chan); + enum dma_slave_buswidth dev_width; + u32 burst; + + if (!is_slave_direction(dir)) + return 0; + + if (dir == DMA_DEV_TO_MEM) { + dev_width = echan->cfg.src_addr_width; + burst = echan->cfg.src_maxburst; + } else { + burst = echan->cfg.dst_maxburst; + dev_width = echan->cfg.dst_addr_width; + } + + /* CCNT: 16bit unsigned. Number of bursts */ + return dev_width * burst * (SZ_64K - 1); +} + static int edma_dma_pause(struct dma_chan *chan) { struct edma_chan *echan = to_edma_chan(chan); @@ -1850,6 +1872,7 @@ static void edma_dma_init(struct edma_cc *ecc, bool legacy_mode) s_ddev->device_issue_pending = edma_issue_pending; s_ddev->device_tx_status = edma_tx_status; s_ddev->device_config = edma_slave_config; + s_ddev->device_get_max_len = edma_get_max_len; s_ddev->device_pause = edma_dma_pause; s_ddev->device_resume = edma_dma_resume; s_ddev->device_terminate_all = edma_terminate_all; -- 2.14.1 Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki