Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756021AbbLAKNW (ORCPT ); Tue, 1 Dec 2015 05:13:22 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:42447 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752542AbbLAKNS (ORCPT ); Tue, 1 Dec 2015 05:13:18 -0500 Subject: Re: [RFC v02 00/15] dmaengine: New 'universal' API for requesting channel To: Arnd Bergmann , References: <1448891145-10766-1-git-send-email-peter.ujfalusi@ti.com> <13562653.8QgTG33tZS@wuerfel> CC: , , , , , , , From: Peter Ujfalusi X-Enigmail-Draft-Status: N1110 Message-ID: <565D729F.2000104@ti.com> Date: Tue, 1 Dec 2015 12:12:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <13562653.8QgTG33tZS@wuerfel> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2547 Lines: 58 On 11/30/2015 04:18 PM, Arnd Bergmann wrote: > On Monday 30 November 2015 15:45:30 Peter Ujfalusi wrote: >> Changes since RFC v01: >> - dma_request_chan(); lost the mask parameter >> - The new API does not rely on RESOURCE_DMA, instead the dma_filter_map table >> will be used to provide the needed information to the filter function in >> legacy mode >> - Extended the example patches to convert most of daVinci to use the new API to >> request the DMA channels. > > Very nice overall. Just a few minor comments. > >> static struct dma_filter_map da830_edma_map[] = { >> DMA_FILTER_ENTRY("davinci-mcasp.0", "rx", EDMA_CTLR_CHAN(0, 0)), >> DMA_FILTER_ENTRY("davinci-mcasp.0", "tx", EDMA_CTLR_CHAN(0, 1)), >> DMA_FILTER_ENTRY("davinci-mcasp.1", "rx", EDMA_CTLR_CHAN(0, 2)), >> DMA_FILTER_ENTRY("davinci-mcasp.1", "tx", EDMA_CTLR_CHAN(0, 3)), >> DMA_FILTER_ENTRY("davinci-mcasp.2", "rx", EDMA_CTLR_CHAN(0, 4)), >> DMA_FILTER_ENTRY("davinci-mcasp.2", "tx", EDMA_CTLR_CHAN(0, 5)), >> DMA_FILTER_ENTRY("spi_davinci.0", "rx", EDMA_CTLR_CHAN(0, 14)), >> DMA_FILTER_ENTRY("spi_davinci.0", "tx", EDMA_CTLR_CHAN(0, 15)), >> DMA_FILTER_ENTRY("da830-mmc.0", "rx", EDMA_CTLR_CHAN(0, 16)), >> DMA_FILTER_ENTRY("da830-mmc.0", "tx", EDMA_CTLR_CHAN(0, 17)), >> DMA_FILTER_ENTRY("spi_davinci.1", "rx", EDMA_CTLR_CHAN(0, 18)), >> DMA_FILTER_ENTRY("spi_davinci.1", "tx", EDMA_CTLR_CHAN(0, 19)), >> }; > > I wonder if we should mandate that the lookup table is 'const'. I had been wondering the same, I'll make it const for the next round. > We could also drop the DMA_FILTER_ENTRY() macro above, and open-code the > table like > > static struct dma_filter_map da830_edma_map[] = { > { "davinci-mcasp.0", "rx", EDMA_CTLR_CHAN(0, 0)}, > { "davinci-mcasp.0", "tx", EDMA_CTLR_CHAN(0, 1)}, > { "davinci-mcasp.1", "rx", EDMA_CTLR_CHAN(0, 2)}, > ... > }; > > which is a little more compact and more obvious, but loses the > named initializers. We would need: { "da830-mmc.0", "rx", (void*)EDMA_CTLR_CHAN(0, 16) }, { "da830-mmc.0", "tx", (void*)EDMA_CTLR_CHAN(0, 17) }, as we need to cast the param. It is still compact, but having to add the (void*) casting makes it a bit ugly. -- P?ter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/