Messages in this thread | | | Date | Thu, 27 Aug 2020 15:11:49 +0200 | From | Paul Cercueil <> | Subject | Re: [PATCH 1/1] USB: PHY: JZ4770: Fix uninitialized value written to HW register |
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Hi Felipe,
Le jeu. 27 août 2020 à 15:58, Felipe Balbi <balbi@kernel.org> a écrit : > > Hi, > > Paul Cercueil <paul@crapouillou.net> writes: >> The 'reg' value was written to a hardware register in >> ingenic_usb_phy_init(), while not being initialized anywhere. > > your patch does a lot more than fix the bug :-) > >> Fixes: 2a6c0b82e651 ("USB: PHY: JZ4770: Add support for new Ingenic >> SoCs.") >> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >> --- >> drivers/usb/phy/phy-jz4770.c | 28 +++++++++++----------------- >> 1 file changed, 11 insertions(+), 17 deletions(-) >> >> diff --git a/drivers/usb/phy/phy-jz4770.c >> b/drivers/usb/phy/phy-jz4770.c >> index d4ee3cb721ea..58771a8688f2 100644 >> --- a/drivers/usb/phy/phy-jz4770.c >> +++ b/drivers/usb/phy/phy-jz4770.c >> @@ -97,7 +97,7 @@ enum ingenic_usb_phy_version { >> struct ingenic_soc_info { >> enum ingenic_usb_phy_version version; >> >> - void (*usb_phy_init)(struct usb_phy *phy); >> + u32 (*usb_phy_init)(struct usb_phy *phy); > > this is not fixing any bug > >> @@ -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.
> >> @@ -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.
Cheers, -Paul
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