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SubjectRe: [PATCH 1/1] USB: PHY: JZ4770: Fix uninitialized value written to HW register
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Date
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在 2020/8/27 下午9:50, Paul Cercueil 写道:
>
>
> Le jeu. 27 août 2020 à 16:25, Felipe Balbi <balbi@kernel.org> a écrit :
>>
>> Hi,
>>
>> Paul Cercueil <paul@crapouillou.net> writes:
>>>>>   @@ -172,7 +172,8 @@ static int ingenic_usb_phy_init(struct usb_phy
>>>>>  *phy)
>>>>>            return err;
>>>>>        }
>>>>>
>>>>>   -    priv->soc_info->usb_phy_init(phy);
>>>>>   +    reg = priv->soc_info->usb_phy_init(phy);
>>>>>   +    writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>>
>>>>  not fixing any bug.
>>>>
>>>>  Looking at the code, the bug follows after this line. It would
>>>> suffice
>>>>  to read REG_USBPCR_OFFSET in order to initialize reg. This bug fix
>>>>  could
>>>>  have been a one liner.
>>>
>>>  There's no need to re-read a register when you have the value readily
>>>  available. It just needs to be returned from the usb_phy_init
>>>  callbacks. But yes, it's not a one-liner.
>>
>> there's a difference between making a bug fix and reworking the behavior
>> of the driver ;-)
>
> The one-liner is actually what changes the behavior of the driver,
> since previously the code did not read back the register.
>
> In this case I guess it's fine, because the register does not have
> volatile bits.
>
>>>>>   @@ -195,19 +196,15 @@ static void ingenic_usb_phy_remove(void *phy)
>>>>>        usb_remove_phy(phy);
>>>>>    }
>>>>>
>>>>>   -static void jz4770_usb_phy_init(struct usb_phy *phy)
>>>>>   +static u32 jz4770_usb_phy_init(struct usb_phy *phy)
>>>>
>>>>  not a bug fix
>>>>
>>>>>    {
>>>>>   -    struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>>>   -    u32 reg;
>>>>>   -
>>>>>   -    reg = USBPCR_AVLD_REG | USBPCR_COMMONONN |
>>>>> USBPCR_IDPULLUP_ALWAYS
>>>>>  |
>>>>>   +    return USBPCR_AVLD_REG | USBPCR_COMMONONN |
>>>>>  USBPCR_IDPULLUP_ALWAYS |
>>>>>            USBPCR_COMPDISTUNE_DFT | USBPCR_OTGTUNE_DFT |
>>>>>  USBPCR_SQRXTUNE_DFT |
>>>>>            USBPCR_TXFSLSTUNE_DFT | USBPCR_TXRISETUNE_DFT |
>>>>>  USBPCR_TXVREFTUNE_DFT |
>>>>>            USBPCR_POR;
>>>>>   -    writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>>
>>>>  not a bug fix
>>>>
>>>>>    }
>>>>>
>>>>>   -static void jz4780_usb_phy_init(struct usb_phy *phy)
>>>>>   +static u32 jz4780_usb_phy_init(struct usb_phy *phy)
>>>>
>>>>  not a bug fix
>>>>
>>>>>   @@ -216,11 +213,10 @@ static void jz4780_usb_phy_init(struct
>>>>>  usb_phy *phy)
>>>>>            USBPCR1_WORD_IF_16BIT;
>>>>>        writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>>>>
>>>>>   -    reg = USBPCR_TXPREEMPHTUNE | USBPCR_COMMONONN | USBPCR_POR;
>>>>>   -    writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>>>   +    return USBPCR_TXPREEMPHTUNE | USBPCR_COMMONONN | USBPCR_POR;
>>>>
>>>>  not a bug fix
>>>>
>>>>>    }
>>>>>
>>>>>   -static void x1000_usb_phy_init(struct usb_phy *phy)
>>>>>   +static u32 x1000_usb_phy_init(struct usb_phy *phy)
>>>>
>>>>  not a bug fix
>>>>
>>>>>    {
>>>>>        struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>>>        u32 reg;
>>>>>   @@ -228,13 +224,12 @@ static void x1000_usb_phy_init(struct usb_phy
>>>>>  *phy)
>>>>>        reg = readl(priv->base + REG_USBPCR1_OFFSET) |
>>>>>  USBPCR1_WORD_IF_16BIT;
>>>>>        writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>>>>
>>>>>   -    reg = USBPCR_SQRXTUNE_DCR_20PCT | USBPCR_TXPREEMPHTUNE |
>>>>>   +    return USBPCR_SQRXTUNE_DCR_20PCT | USBPCR_TXPREEMPHTUNE |
>>>>>            USBPCR_TXHSXVTUNE_DCR_15MV | USBPCR_TXVREFTUNE_INC_25PPT |
>>>>>            USBPCR_COMMONONN | USBPCR_POR;
>>>>>   -    writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>>
>>>>  not a bug fix
>>>>
>>>>>    }
>>>>>
>>>>>   -static void x1830_usb_phy_init(struct usb_phy *phy)
>>>>>   +static u32 x1830_usb_phy_init(struct usb_phy *phy)
>>>>
>>>>  not a bug fix
>>>>
>>>>>    {
>>>>>        struct jz4770_phy *priv = phy_to_jz4770_phy(phy);
>>>>>        u32 reg;
>>>>>   @@ -246,9 +241,8 @@ static void x1830_usb_phy_init(struct usb_phy
>>>>>  *phy)
>>>>>            USBPCR1_DMPD | USBPCR1_DPPD;
>>>>>        writel(reg, priv->base + REG_USBPCR1_OFFSET);
>>>>>
>>>>>   -    reg = USBPCR_IDPULLUP_OTG | USBPCR_VBUSVLDEXT
>>>>>  |    USBPCR_TXPREEMPHTUNE |
>>>>>   +    return USBPCR_IDPULLUP_OTG | USBPCR_VBUSVLDEXT |
>>>>>  USBPCR_TXPREEMPHTUNE |
>>>>>            USBPCR_COMMONONN | USBPCR_POR;
>>>>>   -    writel(reg, priv->base + REG_USBPCR_OFFSET);
>>>>
>>>>  not a bug fix
>>>
>>>  Well, if you don't like my bug fix, next time wait for my Reviewed-by.
>>
>> why so angry? Take a break every once in a while. Besides, someone else
>> already sent the oneliner before you ;-)
>
> I'm just pissed that this patch has not been tested. I don't like
> sloppy work.
>
This is my fault. This error occurred in the v5 version, but was
corrected in the v6 version, but I don't know why v5 was merged into the
mainline and v6 was not merged, which caused this problem.


>> In any case, why should I wait for your Reviewed-by? Get maintainer
>> doesn't list you as the maintainer for it. Do you want to update
>> MAINTAINERS by any chance?
>
> Yes, I thought I was (I'm maintainer of all Ingenic drivers), that
> also explains why I wasn't Cc'd for the oneliner patch you mentioned...
>
I checked again, get_maintainer did not give the correct information,
which caused my script to not add Paul to the cc list.
> IIRC Zhou has a patch to move the driver to drivers/phy/, I'll add
> myself as maintainer once it's moved there.
>
I'll resend it soon.


Thanks and best regards!

> -Paul
>

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