On Mon, Jun 22, 2015 at 02:31:00PM +0300, Peter Ujfalusi wrote: > On 06/12/2015 03:58 PM, Vinod Koul wrote: > > Sorry this slipped thru > > I was away for a week anyways ;) > > > Thinking about it again, I think we should coverge to two APIs and mark the > > legacy depracuated and look to convert folks and phase that out > > Currently, w/o this series we have these APIs: > /* to be used with DT/ACPI */ > dma_request_slave_channel(dev, name) /* NULL on failure */ > dma_request_slave_channel_reason(dev, name) /* error code on failure */ > > /* Legacy mode only - no DT/ACPI lookup */ > dma_request_channel(mask, fn, fn_param) /* NULL on failure */ > > /* to be used with DT/ACPI or legacy boot */ > dma_request_slave_channel_compat(mask, fn, fn_param, dev, name) /* NULL on > failure */ > > To request _any_ channel to be used for memcpy one has to use > dma_request_channel(mask, NULL, NULL); > > If I did not missed something. I dont think so :) > As we need different types of parameters for DT/ACPI and legacy (non DT/ACPI > lookup) and the good API names are already taken, we might need to settle: > > /* to be used with DT/ACPI */ > dma_request_slave_channel(dev, name) /* error code on failure */ > - Convert users to check IS_ERR_OR_NULL() instead against NULL > - Mark dma_request_slave_channel_reason() deprecated and convert the current users > > /* to be used with DT/ACPI or legacy boot */ > dma_request_slave_channel_compat(mask, fn, fn_param, dev, name) /* error code > on failure */ > - Convert users to check IS_ERR_OR_NULL() instead against NULL > - Do not try legacy mode if either OF or ACPI failed because of real error Should we keep the filter fn and an API for this, I am still not too sure about that part. Anyway users should be on DT/ACPI. if someone wants filter then let them use dma_request_channel() > > /* Legacy mode only - no DT/ACPI lookup */ > dma_request_channel_legacy(mask, fn, fn_param) /* error code on failure */ > - convert users of dma_request_channel() > - mark dma_request_channel() deprecated Why should we create a new API, how about marking dma_request_channel() as legacy and generic memcpy API and let other users be migrated? > > /* to be used to get a channel for memcpy for example */ > dma_request_any_channel(mask) /* error code on failure */ > - Convert current dma_request_channel(mask, NULL, NULL) users > I know, any of the other function could be prepared to handle this when > parameters are missing, but it is a bit cleaner to have separate API for this. Though it has merits but adds another API. We cna have internal _dma_request_xxx API where parameters are missing and clean but to users single API might be a better idea > > It would be nice to find another name for the > dma_request_slave_channel_compat() so with the new name we could have chance > to rearrange the parameters: (dev, name, mask, fn, fn_param) > > We would end up with the following APIs, all returning with error code on failure: > dma_request_slave_channel(dev, name); > dma_request_channel_legacy(mask, fn, fn_param); > dma_request_slave_channel_compat(mask, fn, fn_param, dev, name); > dma_request_any_channel(mask); This is good idea but still we end up with 4 APIs. Why not just converge to two API, one legacy + memcpy + filer fn and one untimate API for slave? Internally we may have 4 APIs for cleaner handling... Thoughts... ?? -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
