Date: Wed, 8 Jul 2015 16:35:50 +0200 From: Zbigniew Bodek <zbb@semihalf.com> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: Zbigniew Bodek <zbb@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r285270 - head/sys/sys Message-ID: <CAG7dG%2Bw3ynVQAegB%2BciR-wB84zMzziWOcR987o=zMF_mjHrXvg@mail.gmail.com> In-Reply-To: <CAJ-Vmoku0OzPU=v6X3jb04EQqXXrgSFC9=iFxO8JYCri=XX4XQ@mail.gmail.com> References: <201507081353.t68Dr0up028388@repo.freebsd.org> <CAJ-Vmoku0OzPU=v6X3jb04EQqXXrgSFC9=iFxO8JYCri=XX4XQ@mail.gmail.com>
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Because machdep header includes this file (not the other way). Best regards zbb 2015-07-08 16:30 GMT+02:00 Adrian Chadd <adrian.chadd@gmail.com>: > Why is this implemented in sys/sys/bus_dma.h, rather than in a machdep header? > > > -a > > > On 8 July 2015 at 06:53, Zbigniew Bodek <zbb@freebsd.org> wrote: >> Author: zbb >> Date: Wed Jul 8 13:52:59 2015 >> New Revision: 285270 >> URL: https://svnweb.freebsd.org/changeset/base/285270 >> >> Log: >> Add memory barrier to bus_dmamap_sync() >> >> On platforms which are fully IO-coherent, the map might be null. >> We need to guarantee that all data is observable after the >> sync operation is called. Add a memory barrier to ensure that on ARM. >> >> Reviewed by: andrew, kib >> Obtained from: Semihalf >> Sponsored by: The FreeBSD Foundation >> Differential Revision: https://reviews.freebsd.org/D3012 >> >> Modified: >> head/sys/sys/bus_dma.h >> >> Modified: head/sys/sys/bus_dma.h >> ============================================================================== >> --- head/sys/sys/bus_dma.h Wed Jul 8 13:19:13 2015 (r285269) >> +++ head/sys/sys/bus_dma.h Wed Jul 8 13:52:59 2015 (r285270) >> @@ -282,13 +282,25 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, >> void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map); >> >> /* >> - * Perform a synchronization operation on the given map. >> + * Perform a synchronization operation on the given map. If the map >> + * is NULL we have a fully IO-coherent system. On every ARM architecture >> + * there must be a memory barrier placed to ensure that all data >> + * accesses are visible before going any further. >> */ >> void _bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t, bus_dmasync_op_t); >> +#if defined(__arm__) >> + #define __BUS_DMAMAP_SYNC_DEFAULT mb(); >> +#elif defined(__aarch64__) >> + #define __BUS_DMAMAP_SYNC_DEFAULT dmb(sy); >> +#else >> + #define __BUS_DMAMAP_SYNC_DEFAULT {} >> +#endif >> #define bus_dmamap_sync(dmat, dmamap, op) \ >> do { \ >> if ((dmamap) != NULL) \ >> _bus_dmamap_sync(dmat, dmamap, op); \ >> + else \ >> + __BUS_DMAMAP_SYNC_DEFAULT \ >> } while (0) >> >> /* >> > _______________________________________________ > svn-src-all@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/svn-src-all > To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
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