From mboxrd@z Thu Jan 1 00:00:00 1970 From: tushar.behera@linaro.org (Tushar Behera) Date: Fri, 09 Aug 2013 17:05:09 +0530 Subject: [PATCH RFC 46/51] ARM: DMA-API: better handing of DMA masks for coherent allocations In-Reply-To: References: <20130801213420.GL23006@n2100.arm.linux.org.uk> Message-ID: <5204D3ED.70504@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/02/2013 03:50 AM, Russell King wrote: > We need to start treating DMA masks as something which is specific to > the bus that the device resides on, otherwise we're going to hit all > sorts of nasty issues with LPAE and 32-bit DMA controllers in >32-bit > systems, where memory is offset from PFN 0. > > In order to start doing this, we convert the DMA mask to a PFN using > the device specific dma_to_pfn() macro. This is the reverse of the > pfn_to_dma() macro which is used to get the DMA address for the device. > > This gives us a PFN mask, which we can then check against the PFN > limit of the DMA zone. > > Signed-off-by: Russell King > --- > arch/arm/mm/dma-mapping.c | 49 ++++++++++++++++++++++++++++++++++++++++---- > arch/arm/mm/init.c | 2 + > arch/arm/mm/mm.h | 2 + > 3 files changed, 48 insertions(+), 5 deletions(-) > Tested on Arndale board with ARM_LPAE enabled. Tested-by: Tushar Behera -- Tushar Behera