Date: Wed, 9 Oct 2013 14:46:16 -0600 From: Warner Losh <imp@bsdimp.com> To: Adrian Chadd <adrian@FreeBSD.org> Cc: "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: [rfc] implement busdma barrier operation Message-ID: <0ABAE1CE-C4C3-4A3E-843E-E9B450559012@bsdimp.com> In-Reply-To: <CAJ-Vmo=Vyz_QzSki=rV5WX1LxCma7w=52rKOQ6JVsy0zQTRjbg@mail.gmail.com>
index | next in thread | previous in thread | raw e-mail
On Oct 8, 2013, at 6:33 PM, Adrian Chadd wrote: > > I'd like to implement the busdma barrier operation. You'd like to improve the bus space read and write barrier implementation on MIPS. > This is required for > (at least) correct behaviour of devices on the ar9344 (mips74k) core, as > now I actually need to care about the order of device operations. Yup. We should have had something like this all along. You can get rid, I think, of the cache invalidation and write back too, since that's such a huge hit we'll never do that in a generic implementation. The rest of the change looks good to me. Warner > This (and some local uncommitted changes) are required for the ar9344 > ethernet and switchport devices to correctly function. > > I've tested this on the other mips24k hardware I have and it works. But > nothing else (including ath, grr) explicitly uses read/write barriers. I'll > eventually add them. > > I'd like to bounce this to re@ ASAP to get the approval to commit. > > Thanks, > > > -adrian > > > Index: sys/mips/mips/bus_space_generic.c > =================================================================== > --- sys/mips/mips/bus_space_generic.c (revision 256173) > +++ sys/mips/mips/bus_space_generic.c (working copy) > @@ -749,4 +749,8 @@ > if (flags & BUS_SPACE_BARRIER_WRITE) > mips_dcache_wbinv_all(); > #endif > + if (flags & BUS_SPACE_BARRIER_READ) > + rmb(); > + if (flags & BUS_SPACE_BARRIER_WRITE) > + wmb(); > } > _______________________________________________ > freebsd-mips@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-mips > To unsubscribe, send any mail to "freebsd-mips-unsubscribe@freebsd.org"home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?0ABAE1CE-C4C3-4A3E-843E-E9B450559012>