Date: Mon, 3 Apr 2017 15:16:45 +0200 From: Marcin Wojtas <mw@semihalf.com> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: Coherent bus_dma for ARMv7 Message-ID: <CAPv3WKez8ZP=xONvPWGiyL5pQDKO4wGF_qQn=eT1S_LzrGJ74g@mail.gmail.com> In-Reply-To: <CAJ-Vmo=UC9K3e0TJGU86JZ6npzRevjpC3UEwgWrrh9mjCELKMg@mail.gmail.com> References: <CAPv3WKejupH4JG1=_XV6PknnKifxbF0qoVubtMRVtZWEoBZ7xg@mail.gmail.com> <CAPv3WKcG_Y=5zPk-2vGbQfCpiNcWvuUymY8EHRnWsM2FUzcG4Q@mail.gmail.com> <CAJ-Vmo=UC9K3e0TJGU86JZ6npzRevjpC3UEwgWrrh9mjCELKMg@mail.gmail.com>
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Hi Adrian, Frankly we are not such experts in armv6 bus_dma, which looks more complicated than one in arm64, so we thought it's much safer no to mix the two solutions and leave for the user a single switch to decide, which one to pick. Afaik Andrew Turner did the oposite for arm64 (implement not coherent solution on top of coherent bus_dma), however I'm not sure if it's possible here in an easy way - there's also pretty significant risk of regression for all platforms. Please let me know your opinion. Do you think some sort of update of armv6 is doable? Marcin 2017-04-02 2:00 GMT+02:00 Adrian Chadd <adrian.chadd@gmail.com>: > hiya, > > so why's this need to be different? can't it somehow be merged with > the existing busdma code? > > > > -adrian > > > On 31 March 2017 at 07:05, Marcin Wojtas <mw@semihalf.com> wrote: >> Patch with the coherent bus_dma support attached. >> >> Marcin >> >> 2017-03-31 16:01 GMT+02:00 Marcin Wojtas <mw@semihalf.com>: >>> Hi, >>> >>> In current FreeBSD-HEAD ARMv7 platforms, which support hardware IO >>> cache coherency cannot make use of this feature. In our project we >>> implemented coherent variant bus_dma, which is basing on x86 and arm64 >>> approach. Using of above solution is not obligatory and depends on >>> setting newly added option for that purpose. >>> >>> Needless to say, our platform (Marvell Armada 38x) IO performance >>> boosted after switching to it. Do you wish to enable such option in >>> HEAD? >>> >>> Regards, >>> Marcin >> >> _______________________________________________ >> freebsd-arm@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-arm >> To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"
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