Re: [PATCH] ata: dwc: add DMADEVICES dependency

From	Måns Rullgård <mans@mansr.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] ata: dwc: add DMADEVICES dependency
Date	2016-05-11 15:20 +0200
Message-ID	<rxCds-zl-9@gated-at.bofh.it> (permalink)
References	<rxBKq-8nL-3@gated-at.bofh.it> <rxBU7-8tb-25@gated-at.bofh.it> <rxCdt-zl-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Arnd Bergmann <arnd@arndb.de> writes:

> On Wednesday 11 May 2016 13:57:08 Måns Rullgård wrote:
>> > diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
>> > index 41b0725e58ad..8f7a4a4d2566 100644
>> > --- a/drivers/ata/Kconfig
>> > +++ b/drivers/ata/Kconfig
>> > @@ -322,7 +322,7 @@ config SATA_DWC
>> >
>> >  config SATA_DWC_OLD_DMA
>> >       bool "Support old device trees"
>> > -     depends on SATA_DWC
>> > +     depends on SATA_DWC && DMADEVICES
>> >       select DW_DMAC_CORE
>> >       default y if 460EX
>> >       help
>> > -- 
>> 
>> Isn't the proper fix here to have DW_DMAC_CORE select DMADEVICES?
>
> No, all dmaengine drivers depend on DMADEVICES, so that would
> cause a circular dependency.
>
> The normal behavior for DMA slave drivers is to use the generic
> DMA API and have a dependency on DMADEVICES but not on a particular
> DMA engine implementation. In this case, the driver uses an exported
> interface of the dw_dma driver directly, so we also need to select
> that one, but it doesn't mean we can skip the normal dependency.

OK, but then shouldn't the main SATA_DWC have this dependency since it
uses the DMA API?

-- 
Måns Rullgård

Thread

[PATCH] ata: dwc: add DMADEVICES dependency Arnd Bergmann <arnd@arndb.de> - 2016-05-11 14:50 +0200
  Re: [PATCH] ata: dwc: add DMADEVICES dependency Måns Rullgård <mans@mansr.com> - 2016-05-11 15:00 +0200
    Re: [PATCH] ata: dwc: add DMADEVICES dependency Måns Rullgård <mans@mansr.com> - 2016-05-11 15:20 +0200
      Re: [PATCH] ata: dwc: add DMADEVICES dependency Arnd Bergmann <arnd@arndb.de> - 2016-05-11 15:40 +0200
    Re: [PATCH] ata: dwc: add DMADEVICES dependency Arnd Bergmann <arnd@arndb.de> - 2016-05-11 15:20 +0200

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