Re: [PATCH 3/9] ARM: tegra: # of CPU cores detection w/ & w/oHAVE_ARM_SCU

From: Hiroshi Doyu
Date: Thu Dec 20 2012 - 06:22:13 EST


Felipe Balbi <balbi@xxxxxx> wrote @ Thu, 20 Dec 2012 11:06:25 +0100:
...
> > @@ -149,7 +154,26 @@ done:
> > */
> > static void __init tegra_smp_init_cpus(void)
> > {
> > - unsigned int i, ncores = scu_get_core_count(scu_base);
> > + unsigned int i, cpu_id, ncores;
> > + u32 l2ctlr;
> > + phys_addr_t pa;
> > +
> > + cpu_id = read_cpuid(CPUID_ID) & CPU_MASK;
> > + switch (cpu_id) {
> > + case CPU_CORTEX_A15:
> > + asm("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
> > + ncores = ((l2ctlr >> 24) & 3) + 1;
> > + break;
> > + case CPU_CORTEX_A9:
> > + /* Get SCU physical base */
> > + asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (pa));
> > + scu_base = IO_ADDRESS(pa);
> > + ncores = scu_get_core_count(scu_base);
> > + break;
> > + default:
> > + BUG();
>
> instead of bugging out, how about setting ncores to 1 instead ?

Maybe that would be useful in the case of adding new ARM core in the
future.
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