[PATCH] ARM: shmobile: Check r8a7791 MD21 at SMP boot
Magnus Damm
magnus.damm at gmail.com
Wed Feb 26 04:59:16 EST 2014
From: Magnus Damm <damm at opensource.se>
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 at opensource.se>
---
This is a reworked version of the APMU patch previously posted as
[PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Written against renesas-devel-v3.14-rc4-20140226
arch/arm/mach-shmobile/smp-r8a7791.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
--- 0001/arch/arm/mach-shmobile/smp-r8a7791.c
+++ work/arch/arm/mach-shmobile/smp-r8a7791.c 2014-02-26 18:49:39.000000000 +0900
@@ -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_c
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,
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