Re: [PATCH v2 01/11] clk: renesas: rzg2l-cpg: Check reset monitor registers

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Claudiu,

On Thu, Dec 7, 2023 at 8:08 AM Claudiu <claudiu.beznea@xxxxxxxxx> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>
> The hardware manual of both RZ/G2L and RZ/G3S specifies that the 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 their reset
> signal is toggled, leading to failures (on probe or resume from deep sleep
> states).
>
> The same indications are available for RZ/V2M for TYPE-B reset controls.
>
> Fixes: ef3c613ccd68 ("clk: renesas: Add CPG core wrapper for RZ/G2L SoC")
> Fixes: 8090bea32484 ("clk: renesas: rzg2l: Add support for RZ/V2M reset monitor reg")
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> ---
>
> Changes in v2:
> - adapted for CPG versions with monbit (e.g., RZ/V2M)
> - added a fixes tag for RZ/V2M
> - fixed typos in commit description

Thanks for the update!

> --- a/drivers/clk/renesas/rzg2l-cpg.c
> +++ b/drivers/clk/renesas/rzg2l-cpg.c
> @@ -1416,12 +1416,27 @@ 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 mask = BIT(info->resets[id].bit);
> +       s8 monbit = info->resets[id].monbit;
> +       u32 value = mask << 16;
>
>         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) {
> +               reg = CLK_MRST_R(reg);
> +       } else if (monbit >= 0) {
> +               reg = CPG_RST_MON;
> +               mask = BIT(monbit);
> +       } else {
> +               /* Wait for at least one cyc le of the RCLK clock (@ ca. 32 kHz) */

cycle

Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
i.e. will queue in renesas-clk-for-v6.8 with the above fixed.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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