On 05/16/2012 12:24 PM, Jassi Brar wrote: > On 16 May 2012 22:42, Jon Hunter <jon-hunter@xxxxxx> wrote: > >>>> What is still unclear to me, is if you use this token approach how >>>> readable is the device-tree? For example, if you have a client that can >>>> use one of two dmac and for each dmac the request/channel number is >>>> different, then by using a global token how can I determine what the >>>> options available for this client are? >>>> >>> Simple - you/client need not know about any option at all :) >>> >>> Client driver would simply request some channel and if it >>> doesn't get it, it bails out. >>> >>> It would be the DMACs' DT node that would contain that info. >> >> Yes, but what if I am doing some custom application and want to modify >> the mapping that is being used? So I just wanted to make sure it is easy >> to understand assuming that you understand what your h/w is capable of. >> > Any scenario when a client would want to choose which dma controller > it runs on? > > Because when we say a client could be provided a channel on any of the > two given dmacs, it implies that the client wouldn't feel any difference. That's not my point. I am saying for some reason, maybe QoS, _I_ want to specify which mapping used. I am the one that knows how the h/w is being used and _I_ want to customise the dma/channel mapping in the DT, such that when the client asks for it I know what it is getting. Yes to the client, it does not care, but I do. Jon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
