From b82f2922c7fce3ca6b2797a8d9775e9db2817fe9 Mon Sep 17 00:00:00 2001
From: Ryan Lin <ryan.lin@intel.com>
Date: Mon, 22 Sep 2014 23:29:16 -0700
Subject: [PATCH] superio: ite8772f: Exit extemp busy state

It causes fan top speed due to this bug + our board-specific workaround,
and causes invalid temperature sensor readings.

Therefore, re-configure the register "External Temperature Sensor Host
Control Register" to terminate processes when this issue happens.

BUG=chromium:402204
TEST=ran suspend_stress_test 500 times

Change-Id: I6e71b6a46a31b00e541c304f1ed58c1678c1d42e
Signed-off-by: Ryan Lin <ryan.lin@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/219445
Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>
---
 src/superio/ite/it8772f/it8772f.h |  1 +
 src/superio/ite/it8772f/superio.c | 36 +++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/superio/ite/it8772f/it8772f.h b/src/superio/ite/it8772f/it8772f.h
index f881d7a92a..fd676d536a 100644
--- a/src/superio/ite/it8772f/it8772f.h
+++ b/src/superio/ite/it8772f/it8772f.h
@@ -72,6 +72,7 @@
 #define  IT8772F_FAN_CTL_AUTO_SMOOTHING_DIS	(0 << 7)
 #define  IT8772F_FAN_CTL_AUTO_SMOOTHING_EN	(1 << 7)
 #define IT8772F_EXTEMP_STATUS			0x88
+#define  IT8772F_EXTEMP_STATUS_HOST_BUSY		(1 << 0)
 #define IT8772F_EXTEMP_ADDRESS			0x89
 #define IT8772F_EXTEMP_WRITE_LENGTH		0x8a
 #define IT8772F_EXTEMP_READ_LENGTH		0x8b
diff --git a/src/superio/ite/it8772f/superio.c b/src/superio/ite/it8772f/superio.c
index b18d4ab422..10729339ce 100644
--- a/src/superio/ite/it8772f/superio.c
+++ b/src/superio/ite/it8772f/superio.c
@@ -26,6 +26,7 @@
 #include <stdlib.h>
 #include "chip.h"
 #include "it8772f.h"
+#include "delay.h"
 
 static void pnp_enter_ext_func_mode(device_t dev)
 {
@@ -54,6 +55,34 @@ static inline void it8772f_envc_write(struct resource *res, u8 addr, u8 value)
 	outb(value, res->base + 6);
 }
 
+static void it8772f_extemp_force_idle_status(struct resource *res)
+{
+	u8 reg;
+	int retries = 10;
+
+	/* Wait up to 10ms for non-busy state. */
+	while (retries > 0) {
+		reg = it8772f_envc_read(res, IT8772F_EXTEMP_STATUS);
+
+		if ((reg & IT8772F_EXTEMP_STATUS_HOST_BUSY) == 0x0)
+			break;
+
+		retries--;
+
+		mdelay(1);
+	}
+
+	if (retries == 0 && (reg & IT8772F_EXTEMP_STATUS_HOST_BUSY) == 0x1) {
+		/*
+		 * SIO is busy due to unfinished peci transaction.
+		 * Re-configure Register 0x8E to terminate processes.
+		 */
+		it8772f_envc_write(res, IT8772F_EXTEMP_CONTROL,
+			IT8772F_EXTEMP_CONTROL_AUTO_4HZ |
+			IT8772F_EXTEMP_CONTROL_AUTO_START);
+	}
+}
+
 /*
  * Setup External Temperature to read via PECI into TMPINx register
  */
@@ -156,6 +185,13 @@ static void it8772f_init(device_t dev)
 			it8772f_enable_fan(res, 2);
 		if (conf->fan3_enable)
 			it8772f_enable_fan(res, 3);
+
+		/*
+		 * System may get wrong temperature data when SIO is in
+		 * busy state. Therefore, check the status and terminate
+		 * processes if needed.
+		 */
+		it8772f_extemp_force_idle_status(res);
 		break;
 	case IT8772F_GPIO:
 		/* Set GPIO output levels */