[PATCH] phy: rockchip: inno-usb2: fix hang when multiple controllers exit

[Peter Robinson]

On Tue, Apr 6, 2021 at 4:11 PM Icenowy Zheng <icenowy at aosc.io> wrote:
>
> The OHCI and EHCI controllers are both bound to the same PHY. They will
> both do init and power_on operations when the controller is brought up
> and both do power_off and exit when the controller is stopped. However,
> the PHY uclass of U-Boot is not as sane as we thought -- they won't
> maintain a status mark for PHYs, and thus the functions of the PHYs
> could be called for multiple times. Calling init/power_on for multiple
> times have no severe problems, however calling power_off/exit for
> multiple times have a problem -- the first exit call will stop the PHY
> clock, and power_off/exit calls after it still trying to write to PHY
> registers. The write operation to PHY registers will fail because clock
> is already stopped.
>
> Adapt the count mechanism from phy-sun4i-usb to both init/exit and
> power_on/power_off functions to phy-rockchip-inno-usb2 to fix this
> problem. With this stopping USB controllers (manually or before booting
> a kernel) will work.
>
> Signed-off-by: Icenowy Zheng <icenowy at aosc.io>
> Fixes: ac97a9ece14e ("phy: rockchip: Add Rockchip USB2PHY driver")
Tested-by: Peter Robinson <pbrobinson at gmail.com>

Tested on Rock960 and Pinebook Pro with both USB1 and USB2 devices
connected and it fixes issues I have seen. Thanks!

> ---
>  drivers/phy/rockchip/phy-rockchip-inno-usb2.c | 21 +++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> index 62b8ba3a4a..be9cc99d90 100644
> --- a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> +++ b/drivers/phy/rockchip/phy-rockchip-inno-usb2.c
> @@ -62,6 +62,8 @@ struct rockchip_usb2phy {
>         void *reg_base;
>         struct clk phyclk;
>         const struct rockchip_usb2phy_cfg *phy_cfg;
> +       int init_count;
> +       int power_on_count;
>  };
>
>  static inline int property_enable(void *reg_base,
> @@ -92,6 +94,10 @@ static int rockchip_usb2phy_power_on(struct phy *phy)
>         struct rockchip_usb2phy *priv = dev_get_priv(parent);
>         const struct rockchip_usb2phy_port_cfg *port_cfg = us2phy_get_port(phy);
>
> +       priv->power_on_count++;
> +       if (priv->power_on_count != 1)
> +               return 0;
> +
>         property_enable(priv->reg_base, &port_cfg->phy_sus, false);
>
>         /* waiting for the utmi_clk to become stable */
> @@ -106,6 +112,10 @@ static int rockchip_usb2phy_power_off(struct phy *phy)
>         struct rockchip_usb2phy *priv = dev_get_priv(parent);
>         const struct rockchip_usb2phy_port_cfg *port_cfg = us2phy_get_port(phy);
>
> +       priv->power_on_count--;
> +       if (priv->power_on_count != 0)
> +               return 0;
> +
>         property_enable(priv->reg_base, &port_cfg->phy_sus, true);
>
>         return 0;
> @@ -118,6 +128,10 @@ static int rockchip_usb2phy_init(struct phy *phy)
>         const struct rockchip_usb2phy_port_cfg *port_cfg = us2phy_get_port(phy);
>         int ret;
>
> +       priv->init_count++;
> +       if (priv->init_count != 1)
> +               return 0;
> +
>         ret = clk_enable(&priv->phyclk);
>         if (ret) {
>                 dev_err(phy->dev, "failed to enable phyclk (ret=%d)\n", ret);
> @@ -140,6 +154,10 @@ static int rockchip_usb2phy_exit(struct phy *phy)
>         struct udevice *parent = dev_get_parent(phy->dev);
>         struct rockchip_usb2phy *priv = dev_get_priv(parent);
>
> +       priv->init_count--;
> +       if (priv->init_count != 0)
> +               return 0;
> +
>         clk_disable(&priv->phyclk);
>
>         return 0;
> @@ -212,6 +230,9 @@ static int rockchip_usb2phy_probe(struct udevice *dev)
>                 return ret;
>         }
>
> +       priv->power_on_count = 0;
> +       priv->init_count = 0;
> +
>         return 0;
>  }
>
> --
> 2.30.2