[coreboot-gerrit] Change in coreboot[master]: chromeec: Make google_chromeec_wait_for_display wait for HPD

[Daisuke Nojiri (Code Review)]

Daisuke Nojiri has uploaded this change for review. ( https://review.coreboot.org/23801

Change subject: chromeec: Make google_chromeec_wait_for_display wait for HPD
......................................................................

chromeec: Make google_chromeec_wait_for_display wait for 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.

This patch makes google_chromeec_wait_for_display wait until
EC_CMD_GET_HPD returns EC_RES_SUCCESS.

BUG=b:72387533
BRANCH=none
TEST=Verify Depthcharge can show dev warning screen on a type-c
monitor.

Change-Id: I07aee3bcca3bca93db66578014500b578402a4de
Signed-off-by: Daisuke Nojiri 
---
M src/ec/google/chromeec/ec.c
M src/ec/google/chromeec/ec_commands.h
2 files changed, 38 insertions(+), 4 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/01/23801/1

diff --git a/src/ec/google/chromeec/ec.c b/src/ec/google/chromeec/ec.c
index c902c3f..1005266 100644
--- a/src/ec/google/chromeec/ec.c
+++ b/src/ec/google/chromeec/ec.c
@@ -986,7 +986,25 @@
    return 0;
 }

-const static long wait_for_display_timeout_ms = 2000;
+static int google_chromeec_get_hpd(void)
+{
+	struct chromeec_command cmd;
+	cmd.cmd_code = EC_CMD_GET_HPD;
+	cmd.cmd_version = 0;
+	cmd.cmd_data_in = NULL;
+	cmd.cmd_size_in = 0;
+	cmd.cmd_data_out = NULL;
+	cmd.cmd_size_out = 0;
+	cmd.cmd_dev_index = 0;
+	return google_chromeec_command(&cmd) == EC_RES_SUCCESS ? 1 : 0;
+}
+
+/*
+ * TODO: If no monitor is plugged in or other monitor port (e.g. HDMI) is used,
+ * this timeout always needs to expire. Make EC detect type-c device presence
+ * and abort earlier when waiting does not make sense.
+ */
+const static long wait_for_display_timeout_ms = 3000;

#define USB_SID_DISPLAYPORT 0xff01

@@ -994,17 +1012,31 @@
 {
    struct stopwatch sw;

-	printk(BIOS_INFO, "Waiting for display\n");
+	printk(BIOS_INFO, "Waiting for DisplayPort\n");
    stopwatch_init_msecs_expire(&sw, wait_for_display_timeout_ms);
    while (google_chromeec_pd_get_amode(USB_SID_DISPLAYPORT) != 1) {
    	if (stopwatch_expired(&sw)) {
    		printk(BIOS_WARNING,
-			       "Display not ready after %ldms. Abort.\n",
+			       "DisplayPort not ready after %ldms. Abort.\n",
    		       wait_for_display_timeout_ms);
    		return;
    	}
    	mdelay(200);
    }
-	printk(BIOS_INFO, "Display ready after %lu ms\n",
+	printk(BIOS_INFO, "DisplayPort ready after %lu ms\n",
+	       stopwatch_duration_msecs(&sw));
+
+	printk(BIOS_INFO, "Waiting for HPD\n");
+	stopwatch_init_msecs_expire(&sw, wait_for_display_timeout_ms);
+	while (!google_chromeec_get_hpd()) {
+		if (stopwatch_expired(&sw)) {
+			printk(BIOS_WARNING,
+			       "HPD not ready after %ldms. Abort.\n",
+			       wait_for_display_timeout_ms);
+			return;
+		}
+		mdelay(200);
+	}
+	printk(BIOS_INFO, "HPD ready after %lu ms\n",
           stopwatch_duration_msecs(&sw));
 }
diff --git a/src/ec/google/chromeec/ec_commands.h b/src/ec/google/chromeec/ec_commands.h
index 4f46fab..a5a5623 100644
--- a/src/ec/google/chromeec/ec_commands.h
+++ b/src/ec/google/chromeec/ec_commands.h
@@ -4420,6 +4420,8 @@
    uint8_t data[];		/* For string and raw data */
 };

+#define EC_CMD_GET_HPD 0x0121
+
 /*****************************************************************************/
 /* The command range 0x200-0x2FF is reserved for Rotor. */