From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2] of: Set the DMA mask to 64 bits when dma_addr_t is 64-bits Date: Fri, 26 Apr 2013 15:03:53 -0500 Message-ID: <517ADDA9.7020701@gmail.com> References: <1366999565-19498-1-git-send-email-lauraa@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1366999565-19498-1-git-send-email-lauraa-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Laura Abbott Cc: Catalin Marinas , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 04/26/2013 01:06 PM, Laura Abbott wrote: > Currently, of_platform_device_create_pdata always sets the > coherent DMA mask to 32 bits. On ARM systems without CONFIG_ZONE_DMA, > arm_dma_limit gets set to ~0 or 0xFFFFFFFFFFFFFFFF on LPAE based > systems. Since arm_dma_limit represents the smallest dma_mask > on the system, the default of 32 bits prevents any dma_coherent > allocation from succeeding unless clients manually set the > dma mask first. Rather than make every client on an LPAE system set > the mask, set the mask to a 64 bit value on systems with 64-bit > dma addresses. > > Signed-off-by: Laura Abbott > --- > drivers/of/platform.c | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 0970505..c669ab4 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -214,7 +214,11 @@ struct platform_device *of_platform_device_create_pdata( > #if defined(CONFIG_MICROBLAZE) > dev->archdata.dma_mask = 0xffffffffUL; > #endif > +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT > + dev->dev.coherent_dma_mask = DMA_BIT_MASK(64); > +#else > dev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > +#endif How about "DMA_BIT_MASK(sizeof(dma_addr_t) * 8))" and avoid the ifdef. Rob