nyan: implement chipset_reset() for cold/warm reset

For AP hang detection, the warm reset must be implemented. Since
the cold reset is easy, implement it at the same time.

BUG=chrome-os-partner:23822, chrome-os-partner:24789, chrome-os-partner:24558
BRANCH=nyan
TEST=on nyan rev 3.12
power on/off --> work as usual
power on, then apreset cold --> system is cold reset (off, then on)
power off, then apreset cold --> nothing happens. this is fine.
power on, then apreset warm --> system is warm reset (power trail is kept).
power off, then apreset warm --> nothing happens. this is fine.
power on --> system is back to normal again.

Change-Id: I010793b7a2d309e5d606fbc5877e9e3b07c8c5f3
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/181164
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 18 insertions, 22 deletions

diff --git a/power/tegra.c b/power/tegra.c
index b00ceb498e..a6f3ebb639 100644
--- a/power/tegra.c
+++ b/power/tegra.c
@@ -332,11 +332,7 @@ static int tegra_power_init(void)
 		 * The warm reset triggers AP into the Tegra recovery mode (
 		 * flash SPI from USB).
 		 */
-		CPRINTF("[%T assert GPIO_PMIC_WARM_RESET_L for %d ms]\n",
-				PMIC_WARM_RESET_L_HOLD_TIME / MSEC);
-		gpio_set_level(GPIO_PMIC_WARM_RESET_L, 0);
-		usleep(PMIC_WARM_RESET_L_HOLD_TIME);
-		gpio_set_level(GPIO_PMIC_WARM_RESET_L, 1);
+		chipset_reset(0);
 	}
 
 	/* Leave power off only if requested by reset flags */
@@ -378,23 +374,6 @@ void chipset_exit_hard_off(void)
 	 */
 }
 
-void chipset_reset(int is_cold)
-{
-	/*
-	 * TODO(crosbug.com/p/23822): Implement cold reset.  For now, all
-	 * resets are warm resets.
-	 */
-	CPRINTF("[%T EC triggered warm reboot]\n");
-
-	/*
-	 * This is a hack to do an AP warm reboot while still preserving RAM
-	 * contents. This is useful for looking at kernel log message contents
-	 * from previous boot in cases where the AP/OS is hard hung.
-	 */
-	power_request = POWER_REQ_ON;
-	task_wake(TASK_ID_CHIPSET);
-}
-
 void chipset_force_shutdown(void)
 {
 	/* Release the power button, if it was asserted */
@@ -561,6 +540,23 @@ static void power_off(void)
 	CPRINTF("[%T power shutdown complete]\n");
 }
 
+void chipset_reset(int is_cold)
+{
+	if (is_cold) {
+		CPRINTF("[%T EC triggered cold reboot]\n");
+		power_off();
+		/* After XPSHOLD is dropped off, the system will be on again */
+		power_request = POWER_REQ_ON;
+	} else {
+		CPRINTF("[%T EC triggered warm reboot]\n");
+		CPRINTF("[%T assert GPIO_PMIC_WARM_RESET_L for %d ms]\n",
+				PMIC_WARM_RESET_L_HOLD_TIME / MSEC);
+		gpio_set_level(GPIO_PMIC_WARM_RESET_L, 0);
+		usleep(PMIC_WARM_RESET_L_HOLD_TIME);
+		gpio_set_level(GPIO_PMIC_WARM_RESET_L, 1);
+	}
+}
+
 /*
  * Calculates the delay in microseconds to the next time we have to check
  * for a power event,