From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] net: mvpp2: avoid bouncing buffers Date: Mon, 27 Aug 2018 08:48:43 -0700 Message-ID: <20180827154843.GA25821@infradead.org> References: <20180820024730.9147-1-brian.brooks@linaro.org> <20180819.195505.1988137313680465320.davem@davemloft.net> <20180820062326.GA22222@infradead.org> <20180827135524.fv4mxkwjn5bv7p5e@di3> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , David Miller , antoine.tenart@bootlin.com, maxime.chevallier@bootlin.com, ymarkman@marvell.com, stefanc@marvell.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bjorn.topel@intel.com, brian.brooks@arm.com To: Brian Brooks Return-path: Received: from bombadil.infradead.org ([198.137.202.133]:56804 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727065AbeH0Tf5 (ORCPT ); Mon, 27 Aug 2018 15:35:57 -0400 Content-Disposition: inline In-Reply-To: <20180827135524.fv4mxkwjn5bv7p5e@di3> Sender: netdev-owner@vger.kernel.org List-ID: WE should basically never have dev->dma_mask = &dev->coherent_dma_mask, so until that is the case you are doctoring around the symptoms and not the problem. Does the patch below help your case? ---- >>From 6294e0e330851ee06e66ab85b348f1d92d375d7a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 27 Aug 2018 17:23:24 +0200 Subject: driver core: initialize a default DMA mask for platform device We still treat devices without a DMA mask as defaulting to 32-bits for both mask, but a few releases ago we've started warning about such cases, as they require special cases to work around this sloppyness. Add a dma_mask field to struct platform_object so that we can initialize the dma_mask pointer in struct device and initialize both masks to 32-bits by default. Architectures can still override this in arch_setup_pdev_archdata if needed. Note that the code looks a little odd with the various conditionals because we have to support platform_device structures that are statically allocated. Signed-off-by: Christoph Hellwig --- drivers/base/platform.c | 15 +++++++++++++-- include/linux/platform_device.h | 1 + 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/base/platform.c b/drivers/base/platform.c index dff82a3c2caa..baf4b06cf2d9 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -225,6 +225,17 @@ struct platform_object { char name[]; }; +static void setup_pdev_archdata(struct platform_device *pdev) +{ + if (!pdev->dev.coherent_dma_mask) + pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); + if (!pdev->dma_mask) + pdev->dma_mask = DMA_BIT_MASK(32); + if (!pdev->dev.dma_mask) + pdev->dev.dma_mask = &pdev->dma_mask; + arch_setup_pdev_archdata(pdev); +}; + /** * platform_device_put - destroy a platform device * @pdev: platform device to free @@ -271,7 +282,7 @@ struct platform_device *platform_device_alloc(const char *name, int id) pa->pdev.id = id; device_initialize(&pa->pdev.dev); pa->pdev.dev.release = platform_device_release; - arch_setup_pdev_archdata(&pa->pdev); + setup_pdev_archdata(&pa->pdev); } return pa ? &pa->pdev : NULL; @@ -472,7 +483,7 @@ EXPORT_SYMBOL_GPL(platform_device_del); int platform_device_register(struct platform_device *pdev) { device_initialize(&pdev->dev); - arch_setup_pdev_archdata(pdev); + setup_pdev_archdata(pdev); return platform_device_add(pdev); } EXPORT_SYMBOL_GPL(platform_device_register); diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 1a9f38f27f65..d84ec1de6022 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -25,6 +25,7 @@ struct platform_device { int id; bool id_auto; struct device dev; + dma_addr_t dma_mask; u32 num_resources; struct resource *resource; -- 2.18.0