Messages in this thread |  | | | Subject | Re: [PATCH 01/13] [RFC] ipath basic headers | | From | Arjan van de Ven <> | | Date | Sat, 17 Dec 2005 23:25:23 +0100 |
On Sat, 2005-12-17 at 14:19 -0800, Robert Walsh wrote: > > > +{ > > > + void *ssv, *dsv; > > > + uint32_t csv; > > > + __asm__ __volatile__("cld\n\trep\n\tmovsb":"=&c"(csv), "=&D"(dsv), > > > + "=&S"(ssv) > > > + :"0"(cnt), "1"(dest), "2"(src) > > > + :"memory"); > > > +} > > > > No way we're gonna put assembler code into such a driver. > > Why not? The chip (and therefore the driver) only works with Opterons. > It's tied to the HT bus, but PCI or anything like that.
and opterons can already run 2 architectures. And the HT bus is a generic bus.. with public specs. Others than just AMD use it as well.
also.. what is wrong with memcpy and co ?
> > > +static __inline__ uint32_t ipath_kget_kreg32(const ipath_type stype, > > > + ipath_kreg regno) > > > +{ > > > + volatile uint32_t *kreg32; > > > + > > > + if (!devdata[stype].ipath_kregbase) > > > + return ~0; > > > + > > > + kreg32 = (volatile uint32_t *)&devdata[stype].ipath_kregbase[regno]; > > > > volatile use is probably always wrong. but this whole functions looks like > > a very odd wrapper anyway? > > The volatile is there so the compiler doesn't optimize away the read. > This is important, because reads of our hardware have side-effects and > cannot be optimized out.
then you need to use readl() and family most like; they already take care of this anyway.
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