Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756309AbbBFPMX (ORCPT ); Fri, 6 Feb 2015 10:12:23 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:42337 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752389AbbBFPMW (ORCPT ); Fri, 6 Feb 2015 10:12:22 -0500 Date: Fri, 6 Feb 2015 15:12:10 +0000 From: Catalin Marinas To: Murali Karicheri Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "devicetree@vger.kernel.org" , "linux-pci@vger.kernel.org" , Russell King , Arnd Bergmann , Joerg Roedel , Will Deacon , Rob Herring , Bjorn Helgaas , "suravee.suthikulpanit@amd.com" , "grant.likely@linaro.org" Subject: Re: [PATCH v6 3/7] of: fix size when dma-range is not used Message-ID: <20150206151210.GC23190@e104818-lin.cambridge.arm.com> References: <1423173179-10227-1-git-send-email-m-karicheri2@ti.com> <1423173179-10227-4-git-send-email-m-karicheri2@ti.com> <20150206143812.GB20549@localhost> <54D4D59F.6050408@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54D4D59F.6050408@ti.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3097 Lines: 83 On Fri, Feb 06, 2015 at 02:54:23PM +0000, Murali Karicheri wrote: > On 02/06/2015 09:38 AM, Catalin Marinas wrote: > > On Thu, Feb 05, 2015 at 09:52:55PM +0000, 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. Also add > >> code to check invalid values of size configured in DT and log error. > >> > >> 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 | 17 ++++++++++++++++- > >> 1 file changed, 16 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/of/device.c b/drivers/of/device.c > >> index 2de320d..314c8a9 100644 > >> --- a/drivers/of/device.c > >> +++ b/drivers/of/device.c > >> @@ -105,9 +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) { > >> + dev_warn(dev, "Invalid size 0x%llx for dma-range\n", > >> + size); > >> + size = size + 1; > >> + } > >> + > >> + if (!size) { > >> + dev_err(dev, "Adjusted size 0x%llx invalid\n", size); > >> + return; > >> + } > > > > Would it make sense to set coherent_dma_mask to 0 here to make this more > > noticeable? It can be done together with the mask calculation from size. > > I guess you are the following in the code. > > if (!size) { > dev->coherent_dma_mask = 0; > dev_err(dev, "Adjusted size 0x%llx invalid\n", size); > return; > } > > Not sure how this is going to help and how this get handled by the > caller and subsequent logic. Probably it will cause probe to fail, with > some helpful error code. Not sure how it will fail, maybe the driver figures out that DMA isn't available and say something or switch to PIO. I guess you can leave it as 32-bit mask by default for now even in case of size == 0. BTW, since pci_device_add() already sets coherent_dma_mask, you could add another check at the beginning of of_dma_configure(): if (!dev->coherent_dma_mask) dev->coherent_dma_mask = DMA_BIT_MASK(32); That's more of a nitpick as the values are both the same. -- Catalin -- 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/