[PATCH v2 08/13] arm64: kernel: implement debug monitors CPU PM notifiers
From: Lorenzo Pieralisi <hidden>
Date: 2013-10-14 11:03:05
Also in:
linux-pm
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
When a CPU is shutdown either through CPU idle or suspend to RAM, the content of debug monitor registers must be reset or restored to proper values when CPU resume from low power states. This patch implements a CPU PM notifier that allows to restore the content of debug monitor registers to allow proper suspend/resume operations. Signed-off-by: Lorenzo Pieralisi <redacted> --- arch/arm64/kernel/debug-monitors.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index cbfacf7..28ce685 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c@@ -19,6 +19,7 @@ */ #include <linux/cpu.h> +#include <linux/cpu_pm.h> #include <linux/debugfs.h> #include <linux/hardirq.h> #include <linux/init.h>
@@ -154,6 +155,42 @@ static struct notifier_block os_lock_nb = { .notifier_call = os_lock_notify, }; +#ifdef CONFIG_CPU_PM +static DEFINE_PER_CPU(u32, mdscr); + +static int dm_cpu_pm_notify(struct notifier_block *self, unsigned long action, + void *v) +{ + switch (action) { + case CPU_PM_ENTER: + __get_cpu_var(mdscr) = mdscr_read(); + break; + case CPU_PM_EXIT: + clear_os_lock(NULL); + mdscr_write(__get_cpu_var(mdscr)); + break; + case CPU_PM_ENTER_FAILED: + default: + return NOTIFY_DONE; + } + + return NOTIFY_OK; +} + +static struct notifier_block dm_cpu_pm_nb = { + .notifier_call = dm_cpu_pm_notify, +}; + +static void __init debug_monitors_pm_init(void) +{ + cpu_pm_register_notifier(&dm_cpu_pm_nb); +} +#else +static inline void debug_monitors_pm_init(void) +{ +} +#endif + static int debug_monitors_init(void) { /* Clear the OS lock. */
@@ -162,6 +199,7 @@ static int debug_monitors_init(void) /* Register hotplug handler. */ register_cpu_notifier(&os_lock_nb); + debug_monitors_pm_init(); return 0; } postcore_initcall(debug_monitors_init);
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1.8.4