From patchwork Wed Jan 28 11:05:23 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 5731621 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EFF3CBF440 for ; Wed, 28 Jan 2015 21:49:29 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id ECCB020108 for ; Wed, 28 Jan 2015 21:49:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CCAC20219 for ; Wed, 28 Jan 2015 21:49:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112AbbA1VtF (ORCPT ); Wed, 28 Jan 2015 16:49:05 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:45509 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760160AbbA1UdN (ORCPT ); Wed, 28 Jan 2015 15:33:13 -0500 Received: from foss-smtp-na-1.foss.arm.com (unknown [10.80.61.8]) by foss-mx-na.foss.arm.com (Postfix) with ESMTP id 4F5B028E; Wed, 28 Jan 2015 05:05:30 -0600 (CST) Received: from collaborate-mta1.arm.com (highbank-bc01-b06.austin.arm.com [10.112.81.134]) by foss-smtp-na-1.foss.arm.com (Postfix) with ESMTP id C1E075FAD7; Wed, 28 Jan 2015 05:05:27 -0600 (CST) Received: from e104818-lin.cambridge.arm.com (e104818-lin.cambridge.arm.com [10.1.203.148]) by collaborate-mta1.arm.com (Postfix) with ESMTPS id 850F713F87A; Wed, 28 Jan 2015 05:05:25 -0600 (CST) Date: Wed, 28 Jan 2015 11:05:23 +0000 From: Catalin Marinas To: Murali Karicheri Cc: Robin Murphy , "devicetree@vger.kernel.org" , Russell King , Arnd Bergmann , "linux-pci@vger.kernel.org" , Joerg Roedel , Will Deacon , "linux-kernel@vger.kernel.org" , "grant.likely@linaro.org" , "iommu@lists.linux-foundation.org" , Rob Herring , "suravee.suthikulpanit@amd.com" , Bjorn Helgaas , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v4 3/6] of: fix size when dma-range is not used Message-ID: <20150128110523.GC6646@e104818-lin.cambridge.arm.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <1422052359-12384-4-git-send-email-m-karicheri2@ti.com> <54C77616.80301@arm.com> <54C7DF13.20402@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <54C7DF13.20402@ti.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Tue, Jan 27, 2015 at 06:55:15PM +0000, Murali Karicheri wrote: > On 01/27/2015 06:27 AM, Robin Murphy wrote: > > On 23/01/15 22:32, Murali Karicheri wrote: > >> Fix the dma-range size when the DT attribute is missing. i.e set size to > >> dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect > >> overflow when mask is set to max of u64, add a check, log error and > >> return. > >> Some platform use mask format for size in DTS. So add a work around to > >> catch this and fix. > >> > >> Cc: Joerg Roedel > >> Cc: Grant Likely > >> Cc: Rob Herring > >> Cc: Bjorn Helgaas > >> Cc: Will Deacon > >> Cc: Russell King > >> Cc: Arnd Bergmann > >> Cc: Suravee Suthikulpanit > >> > >> Signed-off-by: Murali Karicheri > >> --- > >> drivers/of/device.c | 14 +++++++++++++- > >> 1 file changed, 13 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/of/device.c b/drivers/of/device.c > >> index 2de320d..0a5ff54 100644 > >> --- a/drivers/of/device.c > >> +++ b/drivers/of/device.c > >> @@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct > >> device_node *np) > >> ret = of_dma_get_range(np, &dma_addr, &paddr, &size); > >> if (ret < 0) { > >> dma_addr = offset = 0; > >> - size = dev->coherent_dma_mask; > >> + size = dev->coherent_dma_mask + 1; > >> } else { > >> offset = PFN_DOWN(paddr - dma_addr); > >> + /* > >> + * Add a work around to treat the size as mask + 1 in case > >> + * it is defined in DT as a mask. > >> + */ > >> + if (size & 1) > >> + size = size + 1; > >> dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); > >> } > >> > >> + /* if size is 0, we have an overflow of u64 */ > >> + if (!size) { > >> + dev_err(dev, "invalid size\n"); > >> + return; > >> + } > >> + > > > > This seems potentially fragile to dodgy DTs given that we might also be > > using size to make a mask later. Would it make sense to double-up a > > sanity check as mask-format detection? Something like: > > > > if is_power_of_2(size) > > // use size > > else if is_power_of_2(size + 1) > > // use size + 1 > > else > > // cry > > How about having the logic like this? > > ret = of_dma_get_range(np, &dma_addr, &paddr, &size); > if (ret < 0) { > dma_addr = offset = 0; > size = dev->coherent_dma_mask + 1; > } else { > offset = PFN_DOWN(paddr - dma_addr); > dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset); > } > > if (is_power_of_2(size + 1)) > size = size + 1; > else if (!is_power_of_2(size)) > { > dev_err(dev, "invalid size\n"); > return; > } In of_dma_configure(), we currently assume that the default coherent mask is 32-bit. In this thread: http://article.gmane.org/gmane.linux.kernel/1835096 we talked about setting the coherent mask based on size automatically. I'm not sure about the size but I think we can assume is 32-bit mask + 1 if it is not specified in the DT. Instead of just assuming a default mask, let's assume a default size and create the mask based on this (untested): diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 5b33c6a21807..9ff8d1286b44 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -170,10 +170,10 @@ static void of_dma_configure(struct device *dev) struct iommu_ops *iommu; /* - * Set default dma-mask to 32 bit. Drivers are expected to setup - * the correct supported dma_mask. + * Set default size to cover the 32-bit. Drivers are expected to setup + * the correct size and dma_mask. */ - dev->coherent_dma_mask = DMA_BIT_MASK(32); + size = 1ULL << 32; /* * Set it to coherent_dma_mask by default if the architecture @@ -185,13 +185,24 @@ static void of_dma_configure(struct device *dev) ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size); if (ret < 0) { dma_addr = offset = 0; - size = dev->coherent_dma_mask; } else { offset = PFN_DOWN(paddr - dma_addr); dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset); } dev->dma_pfn_offset = offset; + /* + * Workaround for DTs setting the size to a mask or 0. + */ + if (is_power_of_2(size + 1)) + size += 1; + + /* + * Coherent DMA masks larger than 32-bit must be explicitly set by the + * driver. + */ + dev->coherent_dma_mask = min(DMA_BIT_MASK(32), DMA_BIT_MASK(ilog2(size))); + coherent = of_dma_is_coherent(dev->of_node); dev_dbg(dev, "device is%sdma coherent\n", coherent ? " " : " not ");