From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH 7/7] OF: set dma_mask for ARM Date: Wed, 20 Apr 2011 07:06:52 -0500 Message-ID: <4DAECC5C.6040203@gmail.com> References: <4DAE9540.8040006@gaisler.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4DAE9540.8040006-FkzTOoA/JUlBDgjK7y7TUQ@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-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: Kristoffer Glembo Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: devicetree@vger.kernel.org On 04/20/2011 03:11 AM, Kristoffer Glembo wrote: > Hi, > > Have you gotten any feedback on this? I am facing the same decision > on SPARC32. I need to add dma_mask to get USB working on non-PCI > buses and I'm currently thinking about doing it either the PowerPC > way or going with the dma_mask =&coherent_dma_mask route. It would be > nice if we could get some community agreement on which is the proper > way of doing this. > No, only Grant's original comment. I did switch to using a bus notifier callback to set the dma_mask pointer so I don't need to modify the DT or arch code. Rob > Best regards, Kristoffer Glembo > > > On 11/16/2010 11:24 PM, Grant Likely wrote: >>> On Tue, Nov 16, 2010 at 02:33:55PM -0600, Rob Herring wrote: >>>> From: Rob Herring >>>> >>>> Various drivers require dma_mask to be valid, so it needs to be >>>> setup when doing OF probing on ARM. >>>> >>>> Signed-off-by: Rob Herring >>> >>> I'll let patches 6& 7 lay fallow for the moment. I'm not >>> hugely fond of the powerpc approach (which microblaze copies), >>> but I haven't had a chance to look for a better solution. >>> >> >> Looking at this some more, there's a couple of options I see. >> >> Other buses (ISA, PCI, EISA) have a dma_mask in their struct. So >> perhaps platform_device should just have a dma_mask field. >> >> There are several examples of setting dma_mask =&coherent_dma_mask. >> I'm not sure if this is considered correct. At least on ARM, I >> don't think these would need to be different. >> >> Another option would be using bus notifiers to set the dma_mask >> like platform_data. But that doesn't seem like a good long term >> solution. >> >> Rob