PM debug: allow configurable wakeup from suspend on OMAP GPtimer

Using debugfs, export a configurable wakeup timer to be used to
wakeup system from suspend.

If a non-zero value is written to
/debug/pm_debug/wakeup_timer_seconds, A timer wakeup event will wake
the system and resume after the configured number of seconds.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index ade2e4a6bb7d..ff818aaec6c5 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -36,6 +36,7 @@
 #include <plat/prcm.h>
 #include <plat/gpmc.h>
 #include <plat/dma.h>
+#include <plat/dmtimer.h>
 
 #include <asm/tlbflush.h>
 
@@ -60,6 +61,7 @@
 
 u32 enable_off_mode;
 u32 sleep_while_idle;
+u32 wakeup_timer_seconds;
 
 struct power_state {
 	struct powerdomain *pwrdm;
@@ -535,6 +537,22 @@ out:
 #ifdef CONFIG_SUSPEND
 static suspend_state_t suspend_state;
 
+static void omap2_pm_wakeup_on_timer(u32 seconds)
+{
+	u32 tick_rate, cycles;
+
+	if (!seconds)
+		return;
+
+	tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gptimer_wakeup));
+	cycles = tick_rate * seconds;
+	omap_dm_timer_stop(gptimer_wakeup);
+	omap_dm_timer_set_load_start(gptimer_wakeup, 0, 0xffffffff - cycles);
+
+	pr_info("PM: Resume timer in %d secs (%d ticks at %d ticks/sec.)\n",
+		seconds, cycles, tick_rate);
+}
+
 static int omap3_pm_prepare(void)
 {
 	disable_hlt();
@@ -546,6 +564,9 @@ static int omap3_pm_suspend(void)
 	struct power_state *pwrst;
 	int state, ret = 0;
 
+	if (wakeup_timer_seconds)
+		omap2_pm_wakeup_on_timer(wakeup_timer_seconds);
+
 	/* Read current next_pwrsts */
 	list_for_each_entry(pwrst, &pwrst_list, node)
 		pwrst->saved_state = pwrdm_read_next_pwrst(pwrst->pwrdm);