Revert "npcx: ensure we don't unlock watchdog too soon"

This reverts commit 031c5d2d62dd891622ded885756c03021e934ef2.

Reason for revert: introduced compilation errors:

chip/npcx/spiflashfw/npcx_monitor.c: In function 'sspi_flash_upload':
chip/npcx/spiflashfw/npcx_monitor.c:290:2: error: implicit declaration of function 'watchdog_stop_and_unlock' [-Werror=implicit-function-declaration]
  watchdog_stop_and_unlock();
  ^~~~~~~~~~~~~~~~~~~~~~~~


Original change's description:
> npcx: ensure we don't unlock watchdog too soon
> 
> We cannot unlock the watchdog timer with 3 watch dog ticks of touching
> it per the datasheet. This is actually around 100ms so we should protect
> against this.
> 
> BRANCH=none
> BUG=b:140207603
> TEST=eliminates cold reset issue.
> 
> Change-Id: Iaef59dad9f5640d64d5d430aea87bd16c2efd30d
> Signed-off-by: Jett Rink <jettrink@chromium.org>
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1790302
> Reviewed-by: Scott Collyer <scollyer@chromium.org>
> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
> Reviewed-by: ML Chao <mlchao@nuvoton.corp-partner.google.com>
> Reviewed-by: Furquan Shaikh <furquan@chromium.org>
> Tested-by: Furquan Shaikh <furquan@chromium.org>
> Commit-Queue: Furquan Shaikh <furquan@chromium.org>

Bug: b:140207603
Change-Id: I540fa53c2c568cb789400d55b807a672b182302a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1799293
Reviewed-by: Caveh Jalali <caveh@google.com>
Commit-Queue: Caveh Jalali <caveh@google.com>
Tested-by: Caveh Jalali <caveh@google.com>

4 files changed, 13 insertions, 32 deletions

diff --git a/chip/npcx/spiflashfw/npcx_monitor.c b/chip/npcx/spiflashfw/npcx_monitor.c
index cc327e3440..a0b011476d 100644
--- a/chip/npcx/spiflashfw/npcx_monitor.c
+++ b/chip/npcx/spiflashfw/npcx_monitor.c
@@ -287,7 +287,9 @@ sspi_flash_upload(int spi_offset, int spi_size)
 	}
 
 	/* Unlock & stop watchdog */
-	watchdog_stop_and_unlock();
+	NPCX_WDSDM = 0x87;
+	NPCX_WDSDM = 0x61;
+	NPCX_WDSDM = 0x63;
 
 	/* UMA Unlock */
 	CLEAR_BIT(NPCX_UMA_ECTS, NPCX_UMA_ECTS_UMA_LOCK);
diff --git a/chip/npcx/system.c b/chip/npcx/system.c
index e7895dc3dc..ff18334533 100644
--- a/chip/npcx/system.c
+++ b/chip/npcx/system.c
@@ -44,7 +44,9 @@
 void system_watchdog_reset(void)
 {
 	/* Unlock & stop watchdog registers */
-	watchdog_stop_and_unlock();
+	NPCX_WDSDM = 0x87;
+	NPCX_WDSDM = 0x61;
+	NPCX_WDSDM = 0x63;
 
 	/* Reset TWCFG */
 	NPCX_TWCFG = 0;
@@ -498,7 +500,9 @@ void __enter_hibernate(uint32_t seconds, uint32_t microseconds)
 	CLEAR_BIT(NPCX_ITCTS(ITIM_WDG_NO), NPCX_ITCTS_ITEN);
 
 	/* Unlock & stop watchdog */
-	watchdog_stop_and_unlock();
+	NPCX_WDSDM = 0x87;
+	NPCX_WDSDM = 0x61;
+	NPCX_WDSDM = 0x63;
 
 	/* Initialize watchdog */
 	NPCX_TWCFG = 0; /* Select T0IN clock as watchdog prescaler clock */
diff --git a/chip/npcx/system_chip.h b/chip/npcx/system_chip.h
index 2836a1e4f7..5ca686a86f 100644
--- a/chip/npcx/system_chip.h
+++ b/chip/npcx/system_chip.h
@@ -30,12 +30,9 @@ enum bbram_data_index {
 	BBRM_DATA_INDEX_PANIC_BKUP = 36,       /* Panic data (index 35-63)*/
 };
 
-/* Issue a watchdog reset */
+/* Issue a watchdog reset*/
 void system_watchdog_reset(void);
 
-/* Stops the watchdog timer and unlocks configuration. */
-void watchdog_stop_and_unlock(void);
-
 /*
  * Configure the specific memory addresses in the the MPU
  * (Memory Protection Unit) for Nuvoton different chip series.
diff --git a/chip/npcx/watchdog.c b/chip/npcx/watchdog.c
index 233c875643..44a980326b 100644
--- a/chip/npcx/watchdog.c
+++ b/chip/npcx/watchdog.c
@@ -58,27 +58,6 @@ static uint8_t watchdog_count(void)
 	return cnt;
 }
 
-static timestamp_t last_watchdog_touch;
-void watchdog_stop_and_unlock(void)
-{
-	/*
-	 * Ensure we have waited at least 3 watchdog ticks since touching WD
-	 * timer. 3 / (32768 / 1024) HZ = 93.75ms
-	 */
-	while (time_since32(last_watchdog_touch) < (100 * MSEC))
-		continue;
-
-	NPCX_WDSDM = 0x87;
-	NPCX_WDSDM = 0x61;
-	NPCX_WDSDM = 0x63;
-}
-
-static void touch_watchdog_count(void)
-{
-	NPCX_WDSDM = 0x5C;
-	last_watchdog_touch = get_time();
-}
-
 void __keep watchdog_check(uint32_t excep_lr, uint32_t excep_sp)
 {
 	int  wd_cnt;
@@ -96,8 +75,7 @@ void __keep watchdog_check(uint32_t excep_lr, uint32_t excep_sp)
 		 * Touch watchdog to let UART have enough time
 		 * to print panic info
 		 */
-		touch_watchdog_count();
-
+		NPCX_WDSDM = 0x5C;
 		/* Print panic info */
 		watchdog_trace(excep_lr, excep_sp);
 		cflush();
@@ -134,7 +112,7 @@ void watchdog_reload(void)
 
 #if 1 /* mark this for testing watchdog */
 	/* Touch watchdog & reset software counter */
-	touch_watchdog_count();
+	NPCX_WDSDM = 0x5C;
 #endif
 
 	/* Enable watchdog interrupt */
@@ -147,7 +125,7 @@ int watchdog_init(void)
 #if SUPPORT_WDG
 	/* Touch watchdog before init if it is already running */
 	if (IS_BIT_SET(NPCX_T0CSR, NPCX_T0CSR_WD_RUN))
-		touch_watchdog_count();
+		NPCX_WDSDM = 0x5C;
 
 	/* Keep prescaler ratio timer0 clock to 1:1024 */
 	NPCX_TWCP = 0x0A;