Change in coreboot[master]: chromeec: Add google_chromeec_wait_for_display

[Daisuke Nojiri (Code Review)]

Daisuke Nojiri has uploaded this change for review. ( https://review.coreboot.org/23745

Change subject: chromeec: Add google_chromeec_wait_for_display
......................................................................

chromeec: Add google_chromeec_wait_for_display

The google_chromeec_wait_for_displa API checks whether a display is
ready or not. It waits in a loop until EC says it entered DisplayPort
alternative mode or times out in 2 seconds.

BUG=b:72387533
BRANCH=none
TEST=Boot Fizz in manual recovery mode. Verify recovery screen is
displayed.

Change-Id: Ieee5db77bd6e147936ea8fc735dcbeffec98c0f8
Signed-off-by: Daisuke Nojiri 
---
M src/ec/google/chromeec/ec.c
M src/ec/google/chromeec/ec.h
2 files changed, 17 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/45/23745/1

diff --git a/src/ec/google/chromeec/ec.c b/src/ec/google/chromeec/ec.c
index 229a710..156357a 100644
--- a/src/ec/google/chromeec/ec.c
+++ b/src/ec/google/chromeec/ec.c
@@ -953,3 +953,19 @@

return 0;
 }
+
+#define  USB_SID_DISPLAYPORT 0xff01
+void google_chromeec_wait_for_display(void)
+{
+	int count = 0;
+	printk(BIOS_INFO, "Waiting for display.");
+	while (google_chromeec_get_alternate_mode(USB_SID_DISPLAYPORT) != 1) {
+		if (count++ > 10) {
+			printk(BIOS_WARNING, " Not ready\n");
+			return;
+		}
+		udelay(200000);
+		printk(BIOS_INFO, ".");
+	}
+	printk(BIOS_INFO, " Ready\n");
+}
diff --git a/src/ec/google/chromeec/ec.h b/src/ec/google/chromeec/ec.h
index dde23c1..45d6f55 100644
--- a/src/ec/google/chromeec/ec.h
+++ b/src/ec/google/chromeec/ec.h
@@ -37,6 +37,7 @@
 int google_ec_running_ro(void);
 void google_chromeec_init(void);
 int google_chromeec_get_alternate_mode(uint16_t svid);
+void google_chromeec_wait_for_display(void);

/* Device events */
 uint64_t google_chromeec_get_device_enabled_events(void);