Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751793AbdIAAfR (ORCPT ); Thu, 31 Aug 2017 20:35:17 -0400 Received: from foss.arm.com ([217.140.101.70]:34238 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbdIAAfQ (ORCPT ); Thu, 31 Aug 2017 20:35:16 -0400 From: Andre Przywara To: =?UTF-8?q?Stefan=20Br=C3=BCns?= Cc: linux-sunxi@googlegroups.com, Maxime Ripard , Chen-Yu Tsai , devicetree@vger.kernel.org, dmaengine@vger.kernel.org, Vinod Koul , Rob Herring , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] dmaengine: sun6i: Add support for Allwinner A64 Date: Fri, 1 Sep 2017 01:31:35 +0100 Message-Id: <20170901003135.10058-1-andre.przywara@arm.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170830233609.13855-4-stefan.bruens@rwth-aachen.de> References: <20170830233609.13855-4-stefan.bruens@rwth-aachen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4203 Lines: 123 Hi, On 31/08/17 00:36, Stefan Brüns wrote: > The A64 SoC has the same dma engine as the H3 (sun8i), with a > reduced amount of physical channels. Add the proper config data > and compatible string to support it. ... > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > index 5f4eee4513e5..6a17c5d63582 100644 > --- a/drivers/dma/sun6i-dma.c > +++ b/drivers/dma/sun6i-dma.c > @@ -1068,6 +1068,12 @@ static struct sun6i_dma_config sun8i_h3_dma_cfg = { > .nr_max_vchans = 34, > .dmac_variant = DMAC_VARIANT_H3, > }; > + > +static struct sun6i_dma_config sun50i_a64_dma_cfg = { > + .nr_max_channels = 8, > + .nr_max_requests = 27, > + .nr_max_vchans = 38, > + .dmac_variant = DMAC_VARIANT_H3, > }; > > static const struct of_device_id sun6i_dma_match[] = { > @@ -1075,6 +1081,7 @@ static const struct of_device_id sun6i_dma_match[] = { > { .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg }, > { .compatible = "allwinner,sun8i-a83t-dma", .data = &sun8i_a83t_dma_cfg }, > { .compatible = "allwinner,sun8i-h3-dma", .data = &sun8i_h3_dma_cfg }, > + { .compatible = "allwinner,sun50i-a64-dma", .data = &sun50i_a64_dma_cfg }, > { /* sentinel */ } > }; > MODULE_DEVICE_TABLE(of, sun6i_dma_match); I was wondering if should use the opportunity to expose those values as DT properties instead of hard-wiring them to a compatible string in the driver every time we add support for a new SoC? We could introduce a new compatible string (say: "allwinner,sunxi-dma"), then describe properties for the number of channels and requests and vchans and parse those from the DT at probe time. With this we might be able to support future SoCs without Linux *driver* changes, by just providing the right DT. This would have worked already for instance for the A83T support, which just changed those values. For instance with this quick patch below (just compile tested, and without your refactoring). The DT node would then read something like: dma: dma-controller@01c02000 { compatible = "allwinner,sun50i-a64-dma", "allwinner,sunxi-dma"; reg = <0x01c02000 0x1000>; interrupts = ; clocks = <&ccu CLK_BUS_DMA>; resets = <&ccu RST_BUS_DMA>; #dma-cells = <1>; allwinner,max_channels = <8>; allwinner,max_requests = <27>; allwinner,max_vchans = <38>; }; Cheers, Andre. diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c index a2358780ab2c..5ae8032f2065 100644 --- a/drivers/dma/sun6i-dma.c +++ b/drivers/dma/sun6i-dma.c @@ -1033,6 +1033,7 @@ static const struct of_device_id sun6i_dma_match[] = { { .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg }, { .compatible = "allwinner,sun8i-a83t-dma", .data = &sun8i_a83t_dma_cfg }, { .compatible = "allwinner,sun8i-h3-dma", .data = &sun8i_h3_dma_cfg }, + { .compatible = "allwinner,sunxi-dma", .data = NULL }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, sun6i_dma_match); @@ -1051,7 +1052,43 @@ static int sun6i_dma_probe(struct platform_device *pdev) device = of_match_device(sun6i_dma_match, &pdev->dev); if (!device) return -ENODEV; - sdc->cfg = device->data; + if (!device->data) { + struct sun6i_dma_config *config; + + config = devm_kmalloc(&pdev->dev, sizeof(*config), GFP_KERNEL); + if (!config) + return -ENOMEM; + + ret = of_property_read_u32(pdev->dev.of_node, + "allwinner,max_channels", + &config->nr_max_channels); + if (ret) { + dev_err(&pdev->dev, + "missing allwinner,max_channels property\n"); + return ret; + } + + ret = of_property_read_u32(pdev->dev.of_node, + "allwinner,max_requests", + &config->nr_max_requests); + if (ret) { + dev_err(&pdev->dev, + "missing allwinner,max_requests property\n"); + return ret; + } + + ret = of_property_read_u32(pdev->dev.of_node, + "allwinner,max_vchans", + &config->nr_max_vchans); + if (ret) { + dev_err(&pdev->dev, + "missing allwinner,max_vchans property\n"); + return ret; + } + sdc->cfg = config; + } else { + sdc->cfg = device->data; + } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); sdc->base = devm_ioremap_resource(&pdev->dev, res); -- 2.14.1