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 <z...@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-unsubscr...@freebsd.org"
