cr50: remove the pullup on sys_rst on kevin

There is leakage on SYS_RST_ODL from the internal pullup cr50 has on
DIOM0. This change removes the internal pullup on reef.

On Kevin there is a bug preventing the EC from being able to pull
sys_rst_l up high enoug for cr50 to detect that it is pulled high. This
change adds an internal pullup back when cr50 detects that it is on a
kevin or gru.

BUG=chrome-os-partner:56945
BUG=chrome-os-partner:53544
BRANCH=none
TEST=On gru and kevin remove servo verify when apreset is run on the EC
it resets cr50 and the AP. Run pinmux and check that there is a pullup
on diom0 on kevin but not on gru.

Change-Id: Ica4f557745967b93e0bd9c8462916b1f735756ac
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/381322
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

3 files changed, 19 insertions, 6 deletions

diff --git a/board/cr50/board.c b/board/cr50/board.c
index 83d8957e5b..fc0b87dc69 100644
--- a/board/cr50/board.c
+++ b/board/cr50/board.c
@@ -193,9 +193,17 @@ static void init_runlevel(const enum permission_level desired_level)
 	}
 }
 
+static void configure_board_specific_gpios(void)
+{
+	/* Add a pullup to sys_rst_l */
+	if (system_get_board_properties() & BOARD_NEEDS_SYS_RST_PULL_UP)
+		GWRITE_FIELD(PINMUX, DIOM0_CTL, PU, 1);
+}
+
 /* Initialize board. */
 static void board_init(void)
 {
+	configure_board_specific_gpios();
 	init_pmu();
 	init_interrupts();
 	init_trng();
@@ -551,10 +559,16 @@ void system_init_board_properties(void)
 		properties = 0;
 
 		/* Read DIOA1 strap pin */
-		if (gpio_get_level(GPIO_STRAP0))
+		if (gpio_get_level(GPIO_STRAP0)) {
 			/* Strap is pulled high -> Kevin SPI TPM option */
 			properties |= BOARD_SLAVE_CONFIG_SPI;
-		else {
+			/* Add an internal pull up on sys_rst_l */
+			/*
+			 * TODO(crosbug.com/p/54059): Remove once SYS_RST_L can
+			 * be pulled up externally.
+			 */
+			properties |= BOARD_NEEDS_SYS_RST_PULL_UP;
+		} else {
 			/* Strap is low -> Reef I2C TPM option */
 			properties |= BOARD_SLAVE_CONFIG_I2C;
 			/* One PHY is connected to the AP */
diff --git a/board/cr50/gpio.inc b/board/cr50/gpio.inc
index e68124d561..454fe729bc 100644
--- a/board/cr50/gpio.inc
+++ b/board/cr50/gpio.inc
@@ -11,11 +11,8 @@
  * We can assert SYS_RST_L but so can the EC, so we need react if it's pulled
  * low. The ARM core can't trigger an interrupt if it's driving it as an output
  * so we attach two internal GPIOs to the same pad.
- * TODO: Remove this internal pullup at some point. It's only here so that
- * boards that don't have an external pullup don't trigger due to noise.
  */
-GPIO_INT(SYS_RST_L_IN,    PIN(1, 0),  GPIO_INT_FALLING | GPIO_PULL_UP,
-	sys_rst_asserted)
+GPIO_INT(SYS_RST_L_IN,    PIN(1, 0),  GPIO_INT_FALLING, sys_rst_asserted)
 GPIO_INT(AP_ON,           PIN(1, 1),  GPIO_INT_RISING, device_state_on)
 GPIO_INT(EC_ON,           PIN(1, 2),  GPIO_INT_RISING, device_state_on)
 GPIO_INT(SERVO_UART1_ON,  PIN(1, 3),  GPIO_INT_RISING | GPIO_PULL_DOWN,
diff --git a/include/system.h b/include/system.h
index 5bca2c6321..12f771df8d 100644
--- a/include/system.h
+++ b/include/system.h
@@ -478,6 +478,8 @@ void system_clear_retry_counter(void);
 #define BOARD_DISABLE_UART0_RX       (1 << 3)   /* Disable UART0 RX */
 #define BOARD_MARK_UPDATE_ON_USB_REQ (1 << 4)   /* update is good once the   */
 						/* controller gets a request */
+/* TODO(crosbug.com/p/54059): Remove when sys_rst_l has an external pullup */
+#define BOARD_NEEDS_SYS_RST_PULL_UP  (1 << 5)   /* Add a pullup to sys_rst_l */
 
 /**
  * Get board properites