From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Roland Vossen" Date: Sun, 31 Jul 2011 08:36:40 +0000 Subject: Sparc, dma mapping and endianness Message-Id: <4E351418.50101@broadcom.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org Hello David, I have got a DMA capable PCI device that writes its data into host memory. The CPU reads that data. For little endian processor this works fine, but for big endian processors the data has to be endianness swapped before interpretation. The broadcom BCM47XX (MIPS) series has a hardware provision for this: its memory controller defines a 'SDRAM swap window'. I read that the Sparc-V9 64 bit architecture also supports endianness swapping of pages. I wonder if it is easy to make use of this functionality in Linux. Also I wonder if Linux supports an arch agnostic API to accomplish this. I did read Documentation/DMA-mapping.txt but that did not provide more information on this subject to me. Thanks, Roland.