linux-kernel - Re: [PATCH] pinctrl: qcom: use scm

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Message-ID: <CACRpkdYvCHB_1FkHft3875iNZm9cGizFVLQQR56Lr95tEB_kwg@mail.gmail.com>
Date:   Thu, 26 Mar 2020 00:31:57 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Ansuel Smith <ansuelsmth@...il.com>
Cc:     Andy Gross <agross@...nel.org>,
        Ajay Kishore <akisho@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        MSM <linux-arm-msm@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: qcom: use scm_call to route GPIO irq to Apps

On Fri, Mar 13, 2020 at 8:15 PM Ansuel Smith <ansuelsmth@...il.com> wrote:

> For IPQ806x targets, TZ protects the registers that are used to
> configure the routing of interrupts to a target processor.
> To resolve this, this patch uses scm call to route GPIO interrupts
> to application processor. Also the scm call interface is changed.
>
> Signed-off-by: Ajay Kishore <akisho@...eaurora.org>
> Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>

That's advanced. I'd really like Bjorn's review on this.

> +       ret = of_device_is_compatible(pctrl->dev->of_node,
> +                                       "qcom,ipq8064-pinctrl");
>         /* Route interrupts to application cpu */
> -       val = msm_readl_intr_target(pctrl, g);
> -       val &= ~(7 << g->intr_target_bit);
> -       val |= g->intr_target_kpss_val << g->intr_target_bit;
> -       msm_writel_intr_target(val, pctrl, g);
> +       if (!ret) {

Can't you just:

if (!of_device_is_compatible(pctrl->dev->of_node, "qcom,ipq8064-pinctrl")) {

OK maybe nitpicky.

> +               val = msm_readl_intr_target(pctrl, g);
> +               val &= ~(7 << g->intr_target_bit);
> +               val |= g->intr_target_kpss_val << g->intr_target_bit;
> +               msm_writel_intr_target(val, pctrl, g);
> +       } else {
> +               const __be32 *reg = of_get_property(pctrl->dev->of_node,
> +                                                   "reg", NULL);
> +
> +               if (reg) {
> +                       u32 addr = be32_to_cpup(reg) + g->intr_target_reg;
> +
> +                       qcom_scm_io_readl(addr, &val);
> +                       __iormb();
> +
> +                       val &= ~(7 << g->intr_target_bit);
> +                       val |= g->intr_target_kpss_val << g->intr_target_bit;
> +
> +                       __iowmb();
> +                       ret = qcom_scm_io_writel(addr, val);
> +                       if (ret)
> +                               pr_err("\n Routing interrupts to Apps proc failed");
> +               }

Can we at least put a little comment on top here and explain what is
going on?

Yours,
Linus Walleij