linux-kernel - Re: [PATCH 2/2] ARM: highbank: fix of node handling in highbank_init

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Message-ID: <20221220132513.38d956e0@donnerap.cambridge.arm.com>
Date:   Tue, 20 Dec 2022 13:25:13 +0000
From:   Andre Przywara <andre.przywara@....com>
To:     Martin Kaiser <martin@...ser.cx>
Cc:     Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] ARM: highbank: fix of node handling in
 highbank_init_irq

On Sun, 18 Dec 2022 15:26:47 +0100
Martin Kaiser <martin@...ser.cx> wrote:

Hi Martin,

thanks for taking care of this.

> highbank_init calls of_find_compatible_node and discards the returned
> node. We should save the node and call of_node_put on it when finished.
> 
> Signed-off-by: Martin Kaiser <martin@...ser.cx>
> ---
>  arch/arm/mach-highbank/highbank.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-highbank/highbank.c b/arch/arm/mach-highbank/highbank.c
> index 97ccb8c1b3cd..54eb1422ef8f 100644
> --- a/arch/arm/mach-highbank/highbank.c
> +++ b/arch/arm/mach-highbank/highbank.c
> @@ -50,10 +50,16 @@ static void highbank_l2c310_write_sec(unsigned long val, unsigned reg)
>  
>  static void __init highbank_init_irq(void)
>  {
> +	struct device_node *np;
> +
>  	irqchip_init();
>  
> -	if (of_find_compatible_node(NULL, NULL, "arm,cortex-a9"))
> -		highbank_scu_map_io();
> +	np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9");
> +	if (!np)
> +		return;
> +
> +	highbank_scu_map_io();
> +	of_node_put(np);

Technically the of_node_put() could happen even earlier, since we
use the of_find_compatible_node() call only to figure out if this is the
Cotex-A15 or the A9 part. But it doesn't really matter, and is correct
anyways:

Reviewed-by: Andre Przywara <andre.przywara@....com>

I also quickly boot tested this on a Midway(A15), but don't have a
Highbank(A9) readily set up at the moment.

Cheers,
Andre


>  }
>  
>  static void highbank_power_off(void)