Avoid spurious shutdown on ODROID-XU4 (#1385) (#1386)

It seems that the TPU (thermal monitoring) sometimes reports
unreasonable high temperatures, leading the kernel to trigger a thermal
shutdown. Add a patch which filters out such spurious temperature
readings.

buildroot-external/board/hardkernel/odroid-xu4/patches/linux/0001-ODROID-XU4-Update-hack-avoiding-the-invalid-temperat.patch

@@ -0,0 +1,61 @@
+From d6b82edb420c7df4fa8bb0924dae2476beb649a2 Mon Sep 17 00:00:00 2001
+Message-Id: <d6b82edb420c7df4fa8bb0924dae2476beb649a2.1622398359.git.stefan@agner.ch>
+From: "charles.park" <charles.park@hardkernel.com>
+Date: Fri, 1 Jun 2018 18:12:01 +0900
+Subject: [PATCH] ODROID-XU4: Update hack avoiding the invalid temperature by
+ TMU broken
+
+Change-Id: I6092834427950a50746535458e99bf7089212044
+---
+ drivers/thermal/thermal_helpers.c | 28 ++++++++++++++++++++++++++++
+ 1 file changed, 28 insertions(+)
+
+diff --git a/drivers/thermal/thermal_helpers.c b/drivers/thermal/thermal_helpers.c
+index c94bc824e5d3..2880126c5861 100644
+--- a/drivers/thermal/thermal_helpers.c
++++ b/drivers/thermal/thermal_helpers.c
+@@ -75,6 +75,10 @@ EXPORT_SYMBOL(get_thermal_instance);
+  *
+  * Return: On success returns 0, an error code otherwise
+  */
++
++#define	CRITICAL_TEMP	120000
++int thermal_zone_data[4] = { 0, };
++
+ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
+ {
+ 	int ret = -EINVAL;
+@@ -108,6 +112,30 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
+ 			*temp = tz->emul_temperature;
+ 	}
+ 
++	/* save thermal_zone data */
++	if (!ret)
++		thermal_zone_data[tz->id] = *temp;
++	/*
++	 * This case is that the thermal sensor is broken.
++	 * That's not real temperature. Set the fake temperature value in order to
++	 * avoid reaching the ciritical temperature.
++	 */
++	if ((thermal_zone_data[tz->id] > CRITICAL_TEMP) && (tz->id != 4)) {
++		int i, broken_sensor = 0, correct_temp = 0;
++		for (i = 0; i < 4; i++) {
++			if ((thermal_zone_data[i] <= CRITICAL_TEMP) &&
++			    (correct_temp <= thermal_zone_data[i]))
++				correct_temp = thermal_zone_data[i];
++			if (thermal_zone_data[i] > CRITICAL_TEMP)
++				broken_sensor++;
++		}
++		/*
++		 * if all thermal sensor broken then critical temperature data send
++		 * for system poweroff.
++		 */
++		*temp = (broken_sensor == 4) ? CRITICAL_TEMP : correct_temp;
++	}
++
+ 	mutex_unlock(&tz->lock);
+ exit:
+ 	return ret;
+-- 
+2.31.1
+

buildroot-external/configs/odroid_xu4_defconfig

@@ -3,7 +3,7 @@ BR2_cortex_a7=y
 BR2_DL_DIR="/cache/dl"
 BR2_CCACHE=y
 BR2_CCACHE_DIR="/cache/cc"
-BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_HASSOS_PATH)/patches $(BR2_EXTERNAL_HASSOS_PATH)/board/hardkernel/patches"
+BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_HASSOS_PATH)/patches $(BR2_EXTERNAL_HASSOS_PATH)/board/hardkernel/patches $(BR2_EXTERNAL_HASSOS_PATH)/board/hardkernel/odroid-xu4/patches"
 BR2_TOOLCHAIN_BUILDROOT_GLIBC=y
 BR2_GCC_VERSION_9_X=y
 BR2_OPTIMIZE_2=y