From 277efd30cfc72ec2f44a9bc95d93807b867bd9e9 Mon Sep 17 00:00:00 2001 From: Magnus Damm Date: Wed, 26 Feb 2014 18:59:16 +0900 Subject: [PATCH] ARM: shmobile: Check r8a7791 MD21 at SMP boot 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 Tested-by: Geert Uytterhoeven Signed-off-by: Simon Horman --- arch/arm/mach-shmobile/smp-r8a7791.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-shmobile/smp-r8a7791.c b/arch/arm/mach-shmobile/smp-r8a7791.c index 2df5bd190fe4..ec979529f30f 100644 --- a/arch/arm/mach-shmobile/smp-r8a7791.c +++ b/arch/arm/mach-shmobile/smp-r8a7791.c @@ -20,6 +20,7 @@ #include #include #include +#include #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, -- 2.34.1