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 --- arch/arm/kernel/hw_breakpoint.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c index 28f3c62..f031a4f 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, };
+#ifdef CONFIG_CPU_PM +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); +} +#else +static inline void pm_init(void) +{ +} +#endif + 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. */ register_cpu_notifier(&dbg_reset_nb); + + pm_init(); return 0; } arch_initcall(arch_hw_breakpoint_init);