platform/chrome: cros_ec: Shutdown on EC Panic

When an EC panic is reported, attempt an orderly shutdown.
Force a shutdown after a brief timeout if the orderly shutdown
fails for any reason.

Using the common hw_protection_shutdown utility function since
an EC panic has the potential to cause hw damage.

This is all best effort. EC should also force a hard reset after a
short timeout.
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20230104011524.369764-3-robbarnes@google.com

drivers/platform/chrome/cros_ec_lpc.c

@@ -21,6 +21,7 @@
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
 #include <linux/printk.h>
+#include <linux/reboot.h>
 #include <linux/suspend.h>
 
 #include "cros_ec.h"
@@ -323,6 +324,8 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
 	if (value == ACPI_NOTIFY_CROS_EC_PANIC) {
 		dev_emerg(ec_dev->dev, "CrOS EC Panic Reported. Shutdown is imminent!");
 		blocking_notifier_call_chain(&ec_dev->panic_notifier, 0, ec_dev);
+		/* Begin orderly shutdown. Force shutdown after 1 second. */
+		hw_protection_shutdown("CrOS EC Panic", 1000);
 		/* Do not query for other events after a panic is reported */
 		return;
 	}