linux-kernel - Re: [PATCH 02/14] clk: renesas: rzg2l-cpg: Check reset monitor registers

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Message-ID: <CAMuHMdXTO+cteN7fW+n3=Vzpa5Nk7oxj+sF2vBMLf2gwS=aNGw@mail.gmail.com>
Date:   Thu, 23 Nov 2023 16:53:17 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Claudiu <claudiu.beznea@...on.dev>
Cc:     s.shtylyov@....ru, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        linux@...linux.org.uk, geert+renesas@...der.be,
        magnus.damm@...il.com, mturquette@...libre.com, sboyd@...nel.org,
        linus.walleij@...aro.org, p.zabel@...gutronix.de, arnd@...db.de,
        m.szyprowski@...sung.com, alexandre.torgue@...s.st.com, afd@...com,
        broonie@...nel.org, alexander.stein@...tq-group.com,
        eugen.hristev@...labora.com, sergei.shtylyov@...il.com,
        prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com, linux-renesas-soc@...r.kernel.org,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 02/14] clk: renesas: rzg2l-cpg: Check reset monitor registers

Hi Claudiu,

On Mon, Nov 20, 2023 at 8:01 AM Claudiu <claudiu.beznea@...on.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>
> Hardware manual of both RZ/G2L and RZ/G3S specifies that reset monitor
> registers need to be interrogated when the reset signals are toggled
> (chapters "Procedures for Supplying and Stopping Reset Signals" and
> "Procedure for Activating Modules"). Without this there is a chance that
> different modules (e.g. Ethernet) to not be ready after reset signal is
> toggled leading to failures (on probe or resume from deep sleep states).
>
> Fixes: ef3c613ccd68 ("clk: renesas: Add CPG core wrapper for RZ/G2L SoC")
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

Thanks for your patch!

> In case you apply this patch and patch 1/13 as is, please add a Depend-on
> tag on this patch to point to patch 1/13 for proper backporting.

There is no such Depend-on tag? Anyway, this patch won't apply if 1/13
is not backported...

> --- a/drivers/clk/renesas/rzg2l-cpg.c
> +++ b/drivers/clk/renesas/rzg2l-cpg.c
> @@ -1416,12 +1416,23 @@ static int rzg2l_cpg_assert(struct reset_controller_dev *rcdev,
>         struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
>         const struct rzg2l_cpg_info *info = priv->info;
>         unsigned int reg = info->resets[id].off;
> -       u32 value = BIT(info->resets[id].bit) << 16;
> +       u32 dis = BIT(info->resets[id].bit);
> +       u32 value = dis << 16;
> +       int ret = 0;
>
>         dev_dbg(rcdev->dev, "assert id:%ld offset:0x%x\n", id, CLK_RST_R(reg));
>
>         writel(value, priv->base + CLK_RST_R(reg));
> -       return 0;
> +
> +       if (info->has_clk_mon_regs) {
> +               ret = readl_poll_timeout_atomic(priv->base + CLK_MRST_R(reg), value,
> +                                               value & dis, 10, 200);
> +       } else {
> +               /* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
> +               udelay(35);
> +       }

I think this should also take into account CPG_RST_MON on RZ/V2M,
cfr. rzg2l_cpg_status().

> +
> +       return ret;
>  }
>
>  static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
> @@ -1432,12 +1443,22 @@ static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
>         unsigned int reg = info->resets[id].off;
>         u32 dis = BIT(info->resets[id].bit);
>         u32 value = (dis << 16) | dis;
> +       int ret = 0;
>
>         dev_dbg(rcdev->dev, "deassert id:%ld offset:0x%x\n", id,
>                 CLK_RST_R(reg));
>
>         writel(value, priv->base + CLK_RST_R(reg));
> -       return 0;
> +
> +       if (info->has_clk_mon_regs) {
> +               ret = readl_poll_timeout_atomic(priv->base + CLK_MRST_R(reg), value,
> +                                               !(value & dis), 10, 200);
> +       } else {
> +               /* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
> +               udelay(35);
> +       }

Likewise.

> +
> +       return ret;
>  }
>
>  static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,

The rest LGTM.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds