Messages in this thread | | | Date | Thu, 27 Aug 2020 15:50:41 +0200 | From | Paul Cercueil <> | Subject | Re: [PATCH 1/1] USB: PHY: JZ4770: Fix uninitialized value written to HW register |
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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.
> 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...
IIRC Zhou has a patch to move the driver to drivers/phy/, I'll add myself as maintainer once it's moved there.
-Paul
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