linux-kernel - Re: [PATCH v2 1/5] bus: ti-sysc: Move check for no-reset-on-init

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Message-ID: <20240410180318.ddpbdlnlss7bqweg@dhruva>
Date: Wed, 10 Apr 2024 23:33:18 +0530
From: Dhruva Gole <d-gole@...com>
To: Tony Lindgren <tony@...mide.com>
CC: <linux-omap@...r.kernel.org>,
        Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/5] bus: ti-sysc: Move check for no-reset-on-init

On Apr 10, 2024 at 09:40:05 +0300, Tony Lindgren wrote:
> We are wrongly checking SYSC_QUIRK_NO_RESET_ON_INIT flag in sysc_reset(),
> it can be called also after init from sysc_reinit_module(). Let's fix the
> issue by moving the check to the init code.

I am not able to understand exactly the potential bug here, what was the
issue exactly?
What I am able to infer is this is more of an improvement than fixing a
bug? Maybe I am missing some context, can you help me understand the
potential bug here?

> 
> Fixes: 6a52bc2b81fa ("bus: ti-sysc: Add quirk handling for reset on re-init")

Fixes tag, you might want to CC stable@...r.kernel.org?

> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>  drivers/bus/ti-sysc.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
> --- a/drivers/bus/ti-sysc.c
> +++ b/drivers/bus/ti-sysc.c
> @@ -2145,8 +2145,7 @@ static int sysc_reset(struct sysc *ddata)
>  	sysc_offset = ddata->offsets[SYSC_SYSCONFIG];
>  
>  	if (ddata->legacy_mode ||
> -	    ddata->cap->regbits->srst_shift < 0 ||
> -	    ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)
> +	    ddata->cap->regbits->srst_shift < 0)
>  		return 0;
>  
>  	sysc_mask = BIT(ddata->cap->regbits->srst_shift);
> @@ -2240,12 +2239,14 @@ static int sysc_init_module(struct sysc *ddata)
>  			goto err_main_clocks;
>  	}
>  
> -	error = sysc_reset(ddata);
> -	if (error)
> -		dev_err(ddata->dev, "Reset failed with %d\n", error);
> +	if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)) {
> +		error = sysc_reset(ddata);
> +		if (error)
> +			dev_err(ddata->dev, "Reset failed with %d\n", error);
>  
> -	if (error && !ddata->legacy_mode)
> -		sysc_disable_module(ddata->dev);
> +		if (error && !ddata->legacy_mode)
> +			sysc_disable_module(ddata->dev);
> +	}
>  

-- 
Best regards,
Dhruva