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

Felipe Balbi [off-list ref] wrote @ Thu, 20 Dec 2012 11:06:25 +0100:
...

quoted

@@ -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.