[coreboot-gerrit] New patch to review for coreboot: google/gru: Power-cycle USB ports in developer/recovery modes

[Patrick Georgi (pgeorgi@google.com)]

Patrick Georgi (pgeorgi at google.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17628

-gerrit

commit b02c66a82d452a22109224d2c69ab2bb7ae34525
Author: Julius Werner <jwerner at chromium.org>
Date:   Mon Nov 21 20:14:18 2016 -0800

    google/gru: Power-cycle USB ports in developer/recovery modes
    
    Gru only uses USB 2.0 in firmware to avoid all the madness associated
    with Type-C port orientation and USB 3.0 tuning. We do this by isolating
    the SuperSpeed lines in the Type-C PHY so it looks like they aren't
    connected to the device.
    
    Unfortunately, some devices seem to already get "locked" into SuperSpeed
    mode as soon as they detect Rx terminations once, and can never snap out
    again on their own. Since the terminations are already connected during
    power-on reset we cannot disable them fast enough to prevent this, and
    the only solution we found to date is to power-cycle the whole USB port.
    
    Now, Gru's USB port power is controlled by the EC, and unfortunately we
    have no direct host command to control it. We do however have a command
    to force a certain USB PD "role", and forcing our host into "sink" mode
    makes it stop sourcing power to the port. So for lack of a saner
    solution we'll use this to work around our problem.
    
    BRANCH=gru
    BUG=chrome-os-partner:59346
    TEST=Booted Kevin in recovery mode, confirmed that my "problem stick"
    gets detected immediately (whereas previously I had to unplug/replug
    it). Booted Kevin to OS in both developer and normal mode and confirmed
    that USB still seems to work.
    
    Change-Id: Ib3cceba9baa170b13f01bd5c01bd413be5b441ba
    Signed-off-by: Patrick Georgi <pgeorgi at chromium.org>
    Original-Commit-Id: cd695eda33299e50362f1096c46f2f5260c49036
    Original-Change-Id: I2db3d6d3710d18a8b8030e94eb1ac2e931f22638
    Original-Signed-off-by: Julius Werner <jwerner at chromium.org>
    Original-Reviewed-on: https://chromium-review.googlesource.com/413031
---
 src/mainboard/google/gru/mainboard.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/mainboard/google/gru/mainboard.c b/src/mainboard/google/gru/mainboard.c
index 7e360e7..dd986c4 100644
--- a/src/mainboard/google/gru/mainboard.c
+++ b/src/mainboard/google/gru/mainboard.c
@@ -15,9 +15,11 @@
  */
 
 #include <boardid.h>
+#include <console/console.h>
 #include <delay.h>
 #include <device/device.h>
 #include <device/i2c.h>
+#include <ec/google/chromeec/ec.h>
 #include <gpio.h>
 #include <soc/bl31_plat_params.h>
 #include <soc/clock.h>
@@ -230,6 +232,17 @@ static void configure_display(void)
 	gpio_output(GPIO(4, D, 3), 1); /* CPU3_EDP_VDDEN for P3.3V_DISP */
 }
 
+static void usb_power_cycle(int port)
+{
+	if (google_chromeec_set_usb_pd_role(port, USB_PD_CTRL_ROLE_FORCE_SINK))
+		printk(BIOS_ERR, "ERROR: Cannot force USB%d PD sink\n", port);
+
+	mdelay(10);	/* Make sure USB stick is fully depowered. */
+
+	if (google_chromeec_set_usb_pd_role(port, USB_PD_CTRL_ROLE_TOGGLE_ON))
+		printk(BIOS_ERR, "ERROR: Cannot restore USB%d PD mode\n", port);
+}
+
 static void setup_usb(void)
 {
 	/* A few magic PHY tuning values that improve eye diagram amplitude
@@ -269,6 +282,17 @@ static void setup_usb(void)
 
 	setup_usb_otg0();
 	setup_usb_otg1();
+
+	/*
+	 * Need to power-cycle USB ports for use in firmware, since some devices
+	 * can't fall back to USB 2.0 after they saw SuperSpeed terminations.
+	 * This takes about a dozen milliseconds, so only do it in boot modes
+	 * that have firmware UI (which one could select USB boot from).
+	 */
+	if (display_init_required()) {
+		usb_power_cycle(0);
+		usb_power_cycle(1);
+	}
 }
 
 static void mainboard_init(device_t dev)