diff options
authorDietmar Eggemann <dietmar.eggemann@arm.com>2012-10-14 22:25:37 +0100
committerViresh Kumar <viresh.kumar@linaro.org>2013-01-08 16:20:16 +0530
commita59eed9aca511151189f929f9cc7fc694fe76718 (patch)
parent677c0295a1a7e60f990c52e0925440e010093622 (diff)
ARM: hw_breakpoint: Debug powerdown support for self-hosted debug
This patch introduces debug powerdown support for self-hosted debug for v7 and v7.1 debug architecture for a SinglePower system, i.e. a system without a separate core and debug power domain. On a SinglePower system the OS Lock is lost over a powerdown. If CONFIG_CPU_PM is set the new function pm_init() registers hw_breakpoint with CPU PM for a system supporting OS Save and Restore. Receiving a CPU PM EXIT notifier indicates that a single CPU has exited a low power state. A call to reset_ctrl_regs() is hooked into the CPU PM EXIT notifier chain. This function makes sure that the sticky power-down is clear (only v7 debug), the OS Double Lock is clear (only v7.1 debug) and it clears the OS Lock for v7 debug (for a system supporting OS Save and Restore) and v7.1 debug. Furthermore, it clears any vector-catch events and all breakpoint/watchpoint control/value registers for v7 and v7.1 debug. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 28f3c62b365..f031a4f8293 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -28,6 +28,7 @@
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include <linux/smp.h>
+#include <linux/cpu_pm.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
@@ -1031,6 +1032,31 @@ static struct notifier_block __cpuinitdata dbg_reset_nb = {
.notifier_call = dbg_reset_notify,
+static int dbg_cpu_pm_notify(struct notifier_block *self, unsigned long action,
+ void *v)
+ if (action == CPU_PM_EXIT)
+ reset_ctrl_regs(NULL);
+ return NOTIFY_OK;
+static struct notifier_block __cpuinitdata dbg_cpu_pm_nb = {
+ .notifier_call = dbg_cpu_pm_notify,
+static void __init pm_init(void)
+ if (has_ossr)
+ cpu_pm_register_notifier(&dbg_cpu_pm_nb);
+static inline void pm_init(void)
static int __init arch_hw_breakpoint_init(void)
debug_arch = get_debug_arch();
@@ -1082,6 +1108,8 @@ static int __init arch_hw_breakpoint_init(void)
/* Register hotplug notifier. */
+ pm_init();
return 0;