On Friday 31 August 2012, Stephen Boyd wrote:
> > +static int hvc_dcc_put_chars_v6(uint32_t vt, const char *buf, int count)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < count; i++) {
> > + while (__dcc_getstatus_v6() & DCC_STATUS_TX_V6)
> > + cpu_relax();
> > +
> > + __dcc_putchar_v6(buf[i]);
> > + }
> > +
> > + return count;
> > +}
>
> It's unfortunate that the main logic is duplicated. I wonder if we could
> push the runtime decision slightly lower into the accessor functions
> instead and make some new functions dcc_tx_busy() and dcc_rx_busy() or
> something. Then these loops stay the same.
Agreed. Ideally, you should be able to get the code to be compiled into
the same binary as before for ARMv6+. If only the inline assembly differs,
you can do something like
static inline char __dcc_getchar(void)
{
char __c;
if (__LINUX_ARM_ARCH >= 6)
asm volatile("mrc p14, 0, %0, c0, c5, 0 @ read comms data reg"
: "=r" (__c));
else
asm volatile ("mrc p14, 0, %0, c1, c0 @ read comms data reg"
: "=r" (ret));
isb();
return __c;
}
Arnd
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