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

[Frank Wang]

Hi Icenowy Zheng,

In my view, it is better to implement this mechanism in phy-uclass which 
resemble Linux Kernel have implemented that can avoid do duplication of 
work in each SoC's PHY driver.


BR.
Frank

On 2021/4/6 23:10, Icenowy Zheng 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 <icen...@aosc.io>
Fixes: ac97a9ece14e ("phy: rockchip: Add Rockchip USB2PHY driver")
---
  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;
  }