Clean up EC hibernate logic

system_hibernate(0, 0) now hibernates until a wake pin assert, with no
RTC wake.

BUG=none
TEST=manual

command -> expected reset flags from 'sysinfo'
1. reboot -> soft
2. reboot hard -> power-on hard
3. hibernate (and press power button) -> power-on wake-pin
4. hibernate 3 (and wait for timeout) -> power-on rtc-alarm
5. hibernate 10 (and press power button before 10 sec) -> power-on wake-pin

hibdelay 10
then shut system down and run on battery
10 sec later, system should hibernate.

Change-Id: I399413d265f6fcf808adf9ed1db7b812a1b12fc2
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/29923
Reviewed-by: Vic Yang <victoryang@chromium.org>

chip/lm4/system.c

@@ -210,13 +210,26 @@ void system_set_rtc(uint32_t seconds)
  *
  * @param seconds      Number of seconds to sleep before RTC alarm
  * @param microseconds Number of microseconds to sleep before RTC alarm
- * @param flags        Hibernate wake flags
+ * @param flags        Additional hibernate wake flags
  */
 static void hibernate(uint32_t seconds, uint32_t microseconds, uint32_t flags)
 {
 	uint32_t rtc, rtcss;
 	uint32_t hibctl;
 
+	/* Set up wake reasons and hibernate flags */
+	hibctl = LM4_HIBERNATE_HIBCTL | LM4_HIBCTL_PINWEN;
+	flags |= HIBDATA_WAKE_PIN;
+
+	if (seconds || microseconds) {
+		hibctl |= LM4_HIBCTL_RTCWEN;
+		flags |= HIBDATA_WAKE_RTC;
+	} else {
+		hibctl &= ~LM4_HIBCTL_RTCWEN;
+	}
+	wait_for_hibctl_wc();
+	LM4_HIBERNATE_HIBCTL = hibctl;
+
 	/* Store hibernate flags */
 	hibdata_write(HIBDATA_INDEX_WAKE, flags);
 
@@ -224,10 +237,6 @@ static void hibernate(uint32_t seconds, uint32_t microseconds, uint32_t flags)
 	wait_for_hibctl_wc();
 	LM4_HIBERNATE_HIBIC = LM4_HIBERNATE_HIBRIS;
 
-	/* TODO: PRESERVE RESET FLAGS */
-
-	/* TODO: If sleeping forever, only wake on wake pin. */
-
 	/* Add expected overhead for hibernate register writes */
 	microseconds += HIB_WAIT_USEC * 4;
 
@@ -254,17 +263,15 @@ static void hibernate(uint32_t seconds, uint32_t microseconds, uint32_t flags)
 	wait_for_hibctl_wc();
 	LM4_HIBERNATE_HIBRTCSS = rtcss << 16;
 
-	/* Go to hibernation and wake on RTC match or WAKE pin */
-	hibctl = (LM4_HIBERNATE_HIBCTL | LM4_HIBCTL_RTCWEN |
-		  LM4_HIBCTL_PINWEN | LM4_HIBCTL_HIBREQ);
 	wait_for_hibctl_wc();
-	__enter_hibernate(hibctl);
+	__enter_hibernate(hibctl | LM4_HIBCTL_HIBREQ);
 }
 
-
 void system_hibernate(uint32_t seconds, uint32_t microseconds)
 {
-	hibernate(seconds, microseconds, HIBDATA_WAKE_RTC | HIBDATA_WAKE_PIN);
+	/* Flush console before hibernating */
+	cflush();
+	hibernate(seconds, microseconds, 0);
 }
 
 int system_pre_init(void)

common/system_common.c

@@ -607,24 +607,25 @@ DECLARE_CONSOLE_COMMAND(scratchpad, command_scratchpad,
 
 static int command_hibernate(int argc, char **argv)
 {
-	int seconds;
+	int seconds = 0;
 	int microseconds = 0;
 
-	if (argc < 2)
-		return EC_ERROR_PARAM_COUNT;
-	seconds = strtoi(argv[1], NULL, 0);
+	if (argc >= 2)
+		seconds = strtoi(argv[1], NULL, 0);
 	if (argc >= 3)
 		microseconds = strtoi(argv[2], NULL, 0);
 
-	ccprintf("Hibernating for %d.%06d s\n", seconds, microseconds);
-	cflush();
+	if (seconds || microseconds)
+		ccprintf("Hibernating for %d.%06d s\n", seconds, microseconds);
+	else
+		ccprintf("Hibernating until wake pin asserted.\n");
 
 	system_hibernate(seconds, microseconds);
 
 	return EC_SUCCESS;
 }
 DECLARE_CONSOLE_COMMAND(hibernate, command_hibernate,
-			"sec [usec]",
+			"[sec] [usec]",
 			"Hibernate the EC",
 			NULL);
 

common/x86_power.c

@@ -444,9 +444,10 @@ void x86_power_task(void)
 						hibernate_delay * 1000000ull;
 				time_now = get_time().val;
 				if (time_now > target_time) {
-					/* Time's up. Hibernate as long as
-					 * possible. */
-					system_hibernate(0xffffffff, 0);
+					/* Time's up.  Hibernate until wake pin
+					 * asserted. */
+					CPRINTF("[%T x86 hibernating]\n");
+					system_hibernate(0, 0);
 				}
 				else {
 					/* Wait for a message */

include/system.h

@@ -169,11 +169,21 @@ const char *system_get_chip_vendor(void);
 const char *system_get_chip_name(void);
 const char *system_get_chip_revision(void);
 
-/* TODO: request sleep.  How do we want to handle transitioning
- * to/from low-power states? */
-
-/* Put the EC in hibernate (lowest EC power state) for the specified
- * duration.  Note that this is NOT the same as chipset S4/hibernate. */
+/**
+ * Put the EC in hibernate (lowest EC power state).
+ *
+ * @param seconds	Number of seconds to hibernate.
+ * @param microseconds	Number of microseconds to hibernate.
+ *
+ * The EC will hibernate until the wake pin is asserted.  If seconds and/or
+ * microseconds is non-zero, the EC will also automatically wake after that
+ * period.  If both are zero, the EC will only wake on a wake pin assert.  Very
+ * short hibernation delays do not work well; if non-zero, the delays must be
+ * at least SYSTEM_HIB_MINIMUM_DURATION.
+ *
+ * Note although the name is similar, EC hibernate is NOT the same as chipset
+ * S4/hibernate.
+ */
 void system_hibernate(uint32_t seconds, uint32_t microseconds);
 
 /* Minimum duration to get proper hibernation */