Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751493AbdILKpE (ORCPT ); Tue, 12 Sep 2017 06:45:04 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:52436 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbdILKo7 (ORCPT ); Tue, 12 Sep 2017 06:44:59 -0400 From: Peter Ujfalusi To: , CC: , , , , Subject: [PATCH 5/5] dmaengine: omap-dma: Implement device_get_max_len callback Date: Tue, 12 Sep 2017 13:44:24 +0300 Message-ID: <20170912104424.18495-6-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 v8CAjN5S015432 Content-Length: 1795 Lines: 56 sDMA can support maximum of 65535 number of bursts in one transfer. The limitation is because the CFN counter is 16bit unsigned. Signed-off-by: Peter Ujfalusi --- drivers/dma/omap-dma.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index f6dd849159d8..6418be98a782 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -1297,6 +1297,28 @@ static int omap_dma_slave_config(struct dma_chan *chan, struct dma_slave_config return 0; } +static u32 omap_dma_get_max_len(struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + struct omap_chan *c = to_omap_dma_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 = c->cfg.src_addr_width; + burst = c->cfg.src_maxburst; + } else { + burst = c->cfg.dst_maxburst; + dev_width = c->cfg.dst_addr_width; + } + + /* CFN: 16bit unsigned. Number of bursts */ + return dev_width * burst * (SZ_64K - 1); +} + static int omap_dma_terminate_all(struct dma_chan *chan) { struct omap_chan *c = to_omap_dma_chan(chan); @@ -1478,6 +1500,7 @@ static int omap_dma_probe(struct platform_device *pdev) od->ddev.device_prep_dma_memcpy = omap_dma_prep_dma_memcpy; od->ddev.device_prep_interleaved_dma = omap_dma_prep_dma_interleaved; od->ddev.device_config = omap_dma_slave_config; + od->ddev.device_get_max_len = omap_dma_get_max_len; od->ddev.device_pause = omap_dma_pause; od->ddev.device_resume = omap_dma_resume; od->ddev.device_terminate_all = omap_dma_terminate_all; -- 2.14.1 Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki