From mboxrd@z Thu Jan 1 00:00:00 1970 From: drake@endlessm.com (Daniel Drake) Date: Thu, 7 May 2015 07:21:18 -0600 Subject: dma_alloc_coherent versus streaming DMA, neither works satisfactory In-Reply-To: <554B49F0.1090100@topic.nl> References: <5538DD02.6050401@topic.nl> <3382997.5hgfVKmNXP@wuerfel> <5540D356.50708@topic.nl> <9622793.RaVBbeJMCx@wuerfel> <554B49F0.1090100@topic.nl> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, May 7, 2015 at 5:18 AM, Mike Looijmans wrote: > I reverted all my patches and workarounds. Indeed, the kernel needs a > "coherent" version of the dma_mmap routine, as the current version will map > it as non-cachable, resulting in a big performance hit (and nullifying the > whole idea behind it). > > I'll test it further on my 'hardware' and cook up a patch that correctly > maps the coherent pages. Sorry that I have only read this thread briefly, but I wonder if this is what you are looking for: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-February/325489.html Thanks Daniel