linux-kernel - Re: [PATCH v4 01/10] drivers: qcom: rpmh-rsc: Clean code reading/writing TCS regs/cmds

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Date:   Tue, 14 Apr 2020 10:43:00 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Joe Perches <joe@...ches.com>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Maulik Shah <mkshah@...eaurora.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Evan Green <evgreen@...omium.org>,
        Lina Iyer <ilina@...eaurora.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 01/10] drivers: qcom: rpmh-rsc: Clean code
 reading/writing TCS regs/cmds

Hi,

On Mon, Apr 13, 2020 at 2:35 PM Joe Perches <joe@...ches.com> wrote:
>
> On Mon, 2020-04-13 at 14:18 -0700, Doug Anderson wrote:
> > Hi,
>
> Rehi.
>
> > On Mon, Apr 13, 2020 at 11:21 AM Joe Perches <joe@...ches.com> wrote:
> > > On Mon, 2020-04-13 at 10:04 -0700, Douglas Anderson wrote:
> > > > This patch makes two changes, both of which should be no-ops:
> > > >
> > > > 1. Make read_tcs_reg() / read_tcs_cmd() symmetric to write_tcs_reg() /
> > > >    write_tcs_cmd().
> > > >
> > > > 2. Change the order of operations in the above functions to make it
> > > >    more obvious to me what the math is doing.  Specifically first you
> > > >    want to find the right TCS, then the right register, and then
> > > >    multiply by the command ID if necessary.
> > >
> > > Though these operations are only used a couple times, perhaps
> > > it'd be useful to have static inlines for the calcs.
> > >
> > > > diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> > > []
> > > > @@ -67,28 +67,33 @@
> > > >  #define CMD_STATUS_ISSUED            BIT(8)
> > > >  #define CMD_STATUS_COMPL             BIT(16)
> > >
> > > Maybe something like:
> > >
> > > static inline void __iomem *
> > > tcs_reg_addr(struct rsc_drv drv, int reg, int tcs_id)
> > > {
> > >         return drv->tcs_base + RSC_DRV_TCS_OFFSET * tcs_id + reg;
> > > }
> > >
> > > static inline void __iomem *
> > > tcs_cmd_addr(struct rsc_drv drv, int reg, int tcs_id, int cmd_id)
> > > {
> > >         return tcs_reg_addr(drv, reg, tcs_id) + RSC_DRV_CMD_OFFSET * cmd_id;
> > > }
> > >
> > > > -static u32 read_tcs_reg(struct rsc_drv *drv, int reg, int tcs_id, int cmd_id)
> > > > +static u32 read_tcs_cmd(struct rsc_drv *drv, int reg, int tcs_id, int cmd_id)
> > > >  {
> > > > -     return readl_relaxed(drv->tcs_base + reg + RSC_DRV_TCS_OFFSET * tcs_id +
> > > > +     return readl_relaxed(drv->tcs_base + RSC_DRV_TCS_OFFSET * tcs_id + reg +
> > > >                            RSC_DRV_CMD_OFFSET * cmd_id);
> > >
> > >         return readl_relaxed(tcs_cmd_addr(drv, reg, tcs_id, cmd_id));
> > >
> > > etc...
> >
> > I won't object if you really feel passionately about making that
> > change but at this point it doesn't add tons of extra readability for
> > me personally.
>
> Just a suggestion.

I tried it and after looking at it again, it definitely does make it cleaner.


> > I was kinda hoping that Maulik and my series could
> > land in the next few days since having 16 patches outstanding gets a
> > bit unwieldy.  I'd rather not send out another spin of my series at
> > this point since it's just a bunch more churn in everyone's inboxes.
> > Maybe after they land you can post that as a follow-up cleanup?
>
> If I remember...

http://lore.kernel.org/r/20200414104120.1.Ic70288f256ff0be65cac6a600367212dfe39f6c9@changeid

-Doug