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ARM: shmobile: Check r8a7791 MD21 at SMP boot

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On r8a7791 the hardware boot mode bit MD21 indicates if hardware
debug mode is enabled or not. In case hardware debug mode is enabled
print a warning and refrain from booting secondary CPU cores.

Without this patch Koelsch with SW8-4 set to OFF will hang at SMP boot.

Signed-off-by: Magnus Damm <damm@opensource.se>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Magnus Damm 2014-02-26 18:59:16 +09:00 committed by Simon Horman
parent 835d737d66
commit 277efd30cf
1 changed files with 14 additions and 1 deletions
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15
arch/arm/mach-shmobile/smp-r8a7791.c
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@ -20,6 +20,7 @@
#include <asm/smp_plat.h>
#include <mach/common.h>
#include <mach/r8a7791.h>
#include <mach/rcar-gen2.h>
#define RST 0xe6160000
#define CA15BAR 0x0020
@ -51,9 +52,21 @@ static void __init r8a7791_smp_prepare_cpus(unsigned int max_cpus)
iounmap(p);
}
static int r8a7791_smp_boot_secondary(unsigned int cpu,
struct task_struct *idle)
{
/* Error out when hardware debug mode is enabled */
if (rcar_gen2_read_mode_pins() & BIT(21)) {
pr_warn("Unable to boot CPU%u when MD21 is set\n", cpu);
return -ENOTSUPP;
}
return shmobile_smp_apmu_boot_secondary(cpu, idle);
}
struct smp_operations r8a7791_smp_ops __initdata = {
.smp_prepare_cpus = r8a7791_smp_prepare_cpus,
.smp_boot_secondary = shmobile_smp_apmu_boot_secondary,
.smp_boot_secondary = r8a7791_smp_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_disable = shmobile_smp_cpu_disable,
.cpu_die = shmobile_smp_apmu_cpu_die,