On 02.10.2012 18:41, Matt Porter wrote: > On Tue, Oct 02, 2012 at 03:42:47PM +0200, Daniel Mack wrote: >> On 02.10.2012 13:06, Sekhar Nori wrote: >>> On 10/2/2012 4:03 PM, Daniel Mack wrote: >>>> On 02.10.2012 11:37, Mark Brown wrote: >>>>> On Tue, Oct 02, 2012 at 10:48:53AM +0300, Peter Ujfalusi wrote: >>>>> >>>>>> I also agree that ifdef is not a good solution. >>>>>> It is better to have this information passed as device_data and via DT >>>>>> it can >>>>>> be decided based on the compatible property for the device. >>>>> >>>>> That's not really the problem here - the problem is that the APIs used >>>>> to get the SRAM are DaVinci only so it's not possible to build on OMAP >>>>> or other platforms. The SRAM code needs to move to a standard API. >>>> >>>> What about following Matt Porter's idea and ignore the SRAM code >>>> entirely and port the entire PCM code to generic dmaengine code first? >>>> The EDMA driver needs to learn support for cyclic DMA for that, and I >>>> might give that a try in near future. >>>> >>>> Later on, the SRAM ping-pong code can get added back using genalloc >>>> functions, as Sekhar proposed. That needs to be done by someone who has >>>> access to a Davinci board though, I only have a AM33xx/OMAP here. >>> >>> We cannot "get rid" of SRAM code and add it back "later". It is required >>> for most DaVinci parts. The SRAM code can be converted to use genalloc >>> (conversion should be straightforward and I can help test it) and the >>> code that uses SRAM can probably keep using the private EDMA API till >>> the dmaengine EDMA driver has cyclic DMA support. Matt has already >>> posted patches to move private EDMA APIs to a common location. That >>> should keep AM335x build from breaking. Is this something that is feasible? >> >> Yes - by "later" I just meant in a subsequent patch. But you're probably >> right, we can also do that first. >> >> I'm looking at that right now and the problem seems that we don't have a >> sane way to dynamically look up gen_pools independently of the actual >> run-time platform. All users of gen_pools seem to know which platform >> they run on and access a platform-specific pool. So I don't currently >> see how we could implement multi-platform code, gen_pools are fine but >> don't solve the problem here. >> >> Would it be an idea to add a char* member to gen_pools and a function >> that can be used to dynamically look it up again? If a buffer with a >> certain name exists, we can use it and install that ping-pong buffer, >> otherwise we just don't. While that would be easy to do, it's a >> tree-wide change. >> >> Is there a better way that I miss? > > At the high level there's two platform models we have to handle, the > boot from board file !DT case, and then the boot from DT case. Since > Davinci is just starting DT conversion, we mostly care about the !DT > base in which the struct gen_pool * is passed in pdata to the ASoC > driver. It is then selectable on a per-platform basis where the decision > should be made. > > Given a separate discussion with Sekhar, we're only going to have one > SRAM pool on any DaVinci part right now...this was only a question on > L138 anyway. But regardless, the created gen_pool will be passed via > pdata.
I thought about this too, as mmp does it that way. > Since DT conversion is starting and we need to consider that now, > the idea there is to use the DT-based generic sram driver [1] such that > when we do boot from DT on Davinci, the genpool is provided via phandle > and the pointer extracted with the OF helpers that are part of the > series. A phandle is the cleanest way I think, yes. > That's pretty much it. I'm reworking the backend support as discussed > with Sekhar wrt to my uio_pruss series. I can post a standalone series > that just replaces sram_* with genalloc for davinci ASoC. As you can also test it, it would be easiest if you came up with a patch for that, yes. I can have a look at the dma bits laters, once my OMAP board finally works with the code as it currently stands. I'm still fighting with the mcasp driver right now ... Daniel _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
