Re: [PATCH] power: reset: at91-reset: Optimize at91_reset()

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 07/03/2025 08:38:09+0300, Alexander Shiyan wrote:
> This patch adds a small optimization to the low-level at91_reset()
> function, which includes:
> - Removes the extra branch, since the following store operations
>   already have proper condition checks.
> - Removes the definition of the clobber register r4, since it is
>   no longer used in the code.
> 
> Fixes: fcd0532fac2a ("power: reset: at91-reset: make at91sam9g45_restart() generic")
> Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
>  drivers/power/reset/at91-reset.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> index 036b18a1f90f..511f5a8f8961 100644
> --- a/drivers/power/reset/at91-reset.c
> +++ b/drivers/power/reset/at91-reset.c
> @@ -129,12 +129,11 @@ static int at91_reset(struct notifier_block *this, unsigned long mode,
>  		"	str	%4, [%0, %6]\n\t"
>  		/* Disable SDRAM1 accesses */
>  		"1:	tst	%1, #0\n\t"
> -		"	beq	2f\n\t"
>  		"	strne	%3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
>  		/* Power down SDRAM1 */
>  		"	strne	%4, [%1, %6]\n\t"
>  		/* Reset CPU */
> -		"2:	str	%5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
> +		"	str	%5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
>  
>  		"	b	.\n\t"
>  		:
> @@ -145,7 +144,7 @@ static int at91_reset(struct notifier_block *this, unsigned long mode,
>  		  "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN),
>  		  "r" (reset->data->reset_args),
>  		  "r" (reset->ramc_lpr)
> -		: "r4");
> +	);
>  
>  	return NOTIFY_DONE;
>  }
> -- 
> 2.39.1
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com