| From 3b637e2f9160e1fea82f7e22f8ac2c2c3a64d8c1 Mon Sep 17 00:00:00 2001 |
| From: Magnus Damm <damm@opensource.se> |
| Date: Wed, 26 Feb 2014 18:59:16 +0900 |
| Subject: 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 <damm@opensource.se> |
| Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> |
| Signed-off-by: Simon Horman <horms+renesas@verge.net.au> |
| (cherry picked from commit 277efd30cfc72ec2f44a9bc95d93807b867bd9e9) |
| Signed-off-by: Simon Horman <horms+renesas@verge.net.au> |
| --- |
| 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 <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, |
| -- |
| 2.1.2 |
| |
