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

[Frank Wang]

Hi,


On 2021/4/7 14:43, Icenowy Zheng wrote:
>
> 于 2021年4月7日 GMT+08:00 下午2:42:34, Frank Wang <frank.wang at rock-chips.com> 写到:
>> 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.
> I'm afraid of breaking existing drivers when implementing it in uclass,
> although I agree this will be more clean.

Why would it break existing drivers?
Refer to clk-uclass, the count mechanism was also introduced later from 
commit "e6849e2fd clk: introduce enable_count".
So fix it in framework codes is much better than in each instance 
drivers just like clk-uclass.

BR.
Frank

>
>>
>> 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 <icenowy at 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;
>>>    }
>>>    
>
>