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From:   Quentin Schulz <foss+kernel@0leil.net>
To:     Minas Harutyunyan <hminas@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Quentin Schulz <quentin.schulz@theobroma-systems.com>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        William Wu <william.wu@rock-chips.com>,
        Bin Yang <yangbin@rock-chips.com>,
        Frank Wang <frank.wang@rock-chips.com>
Subject: [PATCH 0/3] usb: dwc2: fix USB peripheral role in dual-role mode on PX30
Date:   Wed,  7 Dec 2022 14:19:15 +0100
Message-Id: <20221206-dwc2-gadget-dual-role-v1-0-36515e1092cd@theobroma-systems.com>
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From: Quentin Schulz <quentin.schulz@theobroma-systems.com>

On Theobroma Ringneck SoM, USB peripheral role when in dual-role mode does not
work and displays the following error message:
dwc2 ff300000.usb: dwc2_core_reset: HANG! Soft Reset timeout GRSTCTL_CSFTRST

The USB sniffer shows nothing and dumping the host registers is stuck on
HCDMA(0) register.

Note that for some reason it works "fine" on PX30-EVB (there's another issue but
not related to/fixed in this patch series).

Since there's no documentation available for this IP, this patch series is
basically just slightly adapted downstream BSP vendor kernel patches and I
cannot unfortunately give more information than what I have.

This patch series was tested on Theobroma Ringneck SoM on Haikou devkit and PX30
EVB. It fixes Ringneck support and does not break PX30-EVB's.

For reference, the content of those commits can be found in tag
linux-5.10-gen-rkr1, and the following commits have been used:
964d50060bf53a8defd1fc561b9261424f25ddad
ad81c375602819a538ad68d979906c05663046e2
6e6adab8f735bc4fe27a67bdc3144d8fa89250d4
7c3a4e60247fd7f7b04d95d15cb12c63a5c20408

Note that Rockchip kernel called a slightly different implementation of
__dwc2_lowlevel_hw_enable instead of dwc2_lowlevel_hw_enable but it seemed more
right to me to call dwc2_lowlevel_hw_enable as done for the forced peripheral
mode.

I'm assuming the patch disabling phy initialization might need to be made
Rockchip-specific?

To: Minas Harutyunyan <hminas@synopsys.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: William Wu <william.wu@rock-chips.com>
Cc: Frank Wang <frank.wang@rock-chips.com>
Cc: Bin Yang <yangbin@rock-chips.com>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>

---
Bin Yang (1):
      usb: dwc2: prevent core phy initialisation

Quentin Schulz (2):
      usb: dwc2: disable lpm feature on Rockchip SoCs
      usb: dwc2: power on/off phy for peripheral mode in dual-role mode

 drivers/usb/dwc2/gadget.c   | 6 ++++--
 drivers/usb/dwc2/hcd.c      | 7 +++++++
 drivers/usb/dwc2/params.c   | 4 ++++
 drivers/usb/dwc2/platform.c | 3 ++-
 4 files changed, 17 insertions(+), 3 deletions(-)
---
base-commit: 76dcd734eca23168cb008912c0f69ff408905235
change-id: 20221206-dwc2-gadget-dual-role-aac67e6d42fd

Best regards,
-- 
Quentin Schulz <quentin.schulz@theobroma-systems.com>