[PATCH 01/18] Virtex: Add uartlite bootwrapper driver

Josh Boyer jwboyer at linux.vnet.ibm.com
Sat Sep 29 06:26:51 EST 2007


On Fri, 28 Sep 2007 14:04:04 -0600
"Grant Likely" <grant.likely at secretlab.ca> wrote:

> On 9/28/07, Arnd Bergmann <arnd at arndb.de> wrote:
> > On Friday 28 September 2007, Grant Likely wrote:
> > > +static void uartlite_putc(unsigned char c)
> > > +{
> > > +while ((in_be32(reg_base + 0x8) & 0x08) != 0); /* spin */
> > > +out_be32(reg_base + 0x4, c);
> > > +}
> >
> > When coding a spin-loop, it's better to do a cpu_relax() between
> > each attempt.
> 
> Is cpu_relax even implemented in the bootwrapper?

No.  And it doesn't need to be :)

josh



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