USB3 regression in RK3399

[Vicente Bergas]

(cut)
>>>>> testing on the Sapphire board, which uses the RK3399 SoC, a regression
>>>>> has been found in v4.16-rc2 wrt v4.15.4 regarding the USB3 type-A port:
>>>>> In v4.15.4 it works in USB2-only mode.
>>>>> In v4.16-rc2 it does not work.
(cut)
>>>> Hmm, I'd guess the main issue would be a missing typec-phy driver
>>>> in your kernel (see drivers/phy/rockchip/phy-rockchip-typec.c
(cut)
>> I suspect that what Heiko says is right and typec-phy fails probing. Could you
(cut)

Hello,
this is the patch to blame for the regression:

>From c301b327aea898af558b2387252a2f5fc0117dee Mon Sep 17 00:00:00 2001
From: Enric Balletbo i Serra <enric.balletbo at collabora.com>
Date: Fri, 15 Dec 2017 12:00:03 +0100
Subject: [PATCH] arm64: dts: rockchip: add usb3-phy otg-port support for rk3399

Add the usb3 phyter for the USB3.0 OTG controller.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>
Signed-off-by: Heiko Stuebner <heiko at sntech.de>
---
 arch/arm64/boot/dts/rockchip/rk3399.dtsi | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
index b4511503878b..7aa2144e0d47 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
@@ -411,8 +411,8 @@
             reg = <0x0 0xfe800000 0x0 0x100000>;
             interrupts = <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH 0>;
             dr_mode = "otg";
-            phys = <&u2phy0_otg>;
-            phy-names = "usb2-phy";
+            phys = <&u2phy0_otg>, <&tcphy0_usb3>;
+            phy-names = "usb2-phy", "usb3-phy";
             phy_type = "utmi_wide";
             snps,dis_enblslpm_quirk;
             snps,dis-u2-freeclk-exists-quirk;
@@ -444,8 +444,8 @@
             reg = <0x0 0xfe900000 0x0 0x100000>;
             interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH 0>;
             dr_mode = "otg";
-            phys = <&u2phy1_otg>;
-            phy-names = "usb2-phy";
+            phys = <&u2phy1_otg>, <&tcphy1_usb3>;
+            phy-names = "usb2-phy", "usb3-phy";
             phy_type = "utmi_wide";
             snps,dis_enblslpm_quirk;
             snps,dis-u2-freeclk-exists-quirk;
-- 
2.16.2


Before that patch, in dwc3_core_get_phy in drivers/usb/dwc3/core.c
  if (IS_ERR(dwc->usb3_generic_phy)) {
    ret = PTR_ERR(dwc->usb3_generic_phy);
    if (ret == -ENOSYS || ret == -ENODEV) {
      dwc->usb3_generic_phy = NULL;
      // USB3 phy not in device tree, OK, continue without.
    } else if (ret == -EPROBE_DEFER) {
    } else {
    }
  }


After that patch, in dwc3_core_get_phy in drivers/usb/dwc3/core.c
  if (IS_ERR(dwc->usb3_generic_phy)) {
    ret = PTR_ERR(dwc->usb3_generic_phy);
    if (ret == -ENOSYS || ret == -ENODEV) {
      // USB3 phy is in device tree now, this branch is no longer taken.
    } else if (ret == -EPROBE_DEFER) {
      return ret;
      // No usb3_phy found, ERROR, bail out.
      // At this point it could continue in degraded usb2 mode,
      //   but it does not.
    } else {
    }
  }

An usb3 phy is not found because no usb3 phy is being registered.
No usb3 phy is being registered because no usb3 phy is being probed at all.
I do not know why it is not being probed.
In the configuration file, CONFIG_PHY_ROCKCHIP_TYPEC is set to y.

So, all in all, there are two bugs:
 1.- The regression: usb3 mode is new and does not work, BUT this
     makes the usb2 mode to be discarded.
 2.- The new feature: usb3 mode does not work.

Regards,
  Vicente.