linux-kernel - Re: [PATCH v3 08/11] PCI: imx6: Simplify pcie_phy_poll

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Date:   Sun, 14 Apr 2019 11:46:52 -0700
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     Lucas Stach <l.stach@...gutronix.de>
Cc:     linux-pci@...r.kernel.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Fabio Estevam <fabio.estevam@....com>,
        Chris Healy <cphealy@...il.com>,
        Leonard Crestez <leonard.crestez@....com>,
        "A.s. Dong" <aisheng.dong@....com>,
        Richard Zhu <hongxing.zhu@....com>,
        dl-linux-imx <linux-imx@....com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 08/11] PCI: imx6: Simplify pcie_phy_poll_ack()

On Fri, Apr 12, 2019 at 9:12 AM Lucas Stach <l.stach@...gutronix.de> wrote:
>
> Am Sonntag, den 31.03.2019, 21:25 -0700 schrieb Andrey Smirnov:
> > Simplify pcie_phy_poll_ack() by incorporating shifting into constant
> > definition and convert the code to use 'bool'. No functional change
> > intended.
> >
> > > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> > > Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> > > Cc: Fabio Estevam <fabio.estevam@....com>
> > > Cc: Chris Healy <cphealy@...il.com>
> > > Cc: Lucas Stach <l.stach@...gutronix.de>
> > > Cc: Leonard Crestez <leonard.crestez@....com>
> > > Cc: "A.s. Dong" <aisheng.dong@....com>
> > > Cc: Richard Zhu <hongxing.zhu@....com>
> > Cc: linux-imx@....com
> > Cc: linux-arm-kernel@...ts.infradead.org
> > Cc: linux-kernel@...r.kernel.org
> > Cc: linux-pci@...r.kernel.org
> > > Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> > index a49e5e491e12..7c3ffb751002 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -112,7 +112,7 @@ struct imx6_pcie {
> > >  #define PCIE_PHY_CTRL_RD           BIT(19)
> >
> >  #define PCIE_PHY_STAT (PL_OFFSET + 0x110)
> > -#define PCIE_PHY_STAT_ACK_LOC 16
> > > +#define PCIE_PHY_STAT_ACK          BIT(16)
> >
> > >  #define PCIE_LINK_WIDTH_SPEED_CONTROL      0x80C
> >
> > @@ -151,16 +151,16 @@ struct imx6_pcie {
> > >  #define PHY_RX_OVRD_IN_LO_RX_DATA_EN               BIT(5)
> > >  #define PHY_RX_OVRD_IN_LO_RX_PLL_EN                BIT(3)
> >
> > -static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, int exp_val)
> > +static int pcie_phy_poll_ack(struct imx6_pcie *imx6_pcie, bool exp_val)
>
> This looks like only going half the way to me. The parameter type is
> changed to bool, but the callers still use 0 and 1 directly. If we use
> bool here the callers should be changed to true/false.
>

OK, will change in next version.

> >  {
> >       struct dw_pcie *pci = imx6_pcie->pci;
> > -     u32 val;
> > +     bool val;
> >       u32 max_iterations = 10;
> >       u32 wait_counter = 0;
> >
> >       do {
> > -             val = dw_pcie_readl_dbi(pci, PCIE_PHY_STAT);
> > -             val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
> > +             val = dw_pcie_readl_dbi(pci, PCIE_PHY_STAT) &
> > +                     PCIE_PHY_STAT_ACK;
>
> I think this needs to be
> val = !!(dw_pcie_readl_dbi(pci, PCIE_PHY_STAT) & PCIE_PHY_STAT_ACK);
> as the ACK bit isn't shifted down into bit position 0 anymore.
>

That should already be taken care of by conversion to bool/_Bool(see
"Using bool" in Documentation/process/coding-style.rst) and was one of
the reasons I converted "val" to that type.

Thanks,
Andrey Smirnov