mainboard/google/fizz: Check HDMI HPD and DisplayPort HPD

Some type-c monitors do not immediately assert HPD. If we continue
to boot without HPD asserted, Depthcharge fails to show pictures
on a monitor even if HPD is asserted later.

Also, if an HDMI monitor is connected, no wait is needed. If only
an HDMI monitor is connected, currently the API always loops until
the stopwatch expires.

This patch will make the AP skip DisplayPort wait loop if it detects
an HDMI monitor. And if an HDMI monitor is not detected, the AP will
wait for DisplayPort mode (like before) but also its HPD signal.

This patch also extends the wait loop time-out to 3 seconds.

BUG=b:72387533
BRANCH=none
TEST=Verify firmware screen is displayed even when a type-c monitor
does not immediately assert HPD. Verify if HDMI monitor is connected,
AP does not wait (and firmware screen is displayed on HDMI monitor).

Change-Id: I0e1afdffbebf4caf35bbb792e7f4637fae89fa49
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://review.coreboot.org/23816
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

1 files changed, 40 insertions, 2 deletions

diff --git a/src/mainboard/google/fizz/ramstage.c b/src/mainboard/google/fizz/ramstage.c
index e5215f87d8..231ed87973 100644
--- a/src/mainboard/google/fizz/ramstage.c
+++ b/src/mainboard/google/fizz/ramstage.c
@@ -14,15 +14,53 @@
  */
 
 #include <bootmode.h>
+#include <console/console.h>
+#include <delay.h>
 #include <ec/google/chromeec/ec.h>
+#include <gpio.h>
+#include <mainboard/google/fizz/gpio.h>
+#include <soc/gpio.h>
 #include <soc/ramstage.h>
+#include <timer.h>
 
 #include "gpio.h"
 
+#define GPIO_HDMI_HPD		GPP_E13
+#define GPIO_DP_HPD		GPP_E14
+
+/* TODO: This can be moved to common directory */
+static void wait_for_hpd(gpio_t gpio, long timeout)
+{
+	struct stopwatch sw;
+
+	printk(BIOS_INFO, "Waiting for HPD\n");
+	gpio_input(gpio);
+
+	stopwatch_init_msecs_expire(&sw, timeout);
+	while (!gpio_get(gpio)) {
+		if (stopwatch_expired(&sw)) {
+			printk(BIOS_WARNING,
+			       "HPD not ready after %ldms. Abort.\n", timeout);
+			return;
+		}
+		mdelay(200);
+	}
+	printk(BIOS_INFO, "HPD ready after %lu ms\n",
+	       stopwatch_duration_msecs(&sw));
+}
+
 void mainboard_silicon_init_params(FSP_SIL_UPD *params)
 {
-	if (display_init_required())
+	static const long display_timeout_ms = 3000;
+
+	/* This is reconfigured back to whatever FSP-S expects by
+	   gpio_configure_pads. */
+	gpio_input(GPIO_HDMI_HPD);
+	if (display_init_required() && !gpio_get(GPIO_HDMI_HPD)) {
 		/* This has to be done before FSP-S runs. */
-		google_chromeec_wait_for_display();
+		if (google_chromeec_wait_for_displayport(display_timeout_ms))
+			wait_for_hpd(GPIO_DP_HPD, display_timeout_ms);
+	}
+
 	gpio_configure_pads(gpio_table, ARRAY_SIZE(gpio_table));
 }