Re: [PATCH] soc: renesas: rcar-sysc: Use readl_poll_timeout_atomic()

From: "Niklas Söderlund" <niklas.soderlund@ragnatech.se>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Magnus Damm <magnus.damm@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	linux-renesas-soc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] soc: renesas: rcar-sysc: Use readl_poll_timeout_atomic()
Date: Fri, 22 Jan 2021 20:04:17 +0100	[thread overview]
Message-ID: <YAshsZKxlmjjKJTH@oden.dyn.berto.se> (raw)
In-Reply-To: <20210122113637.2833489-1-geert+renesas@glider.be>

Hi Geert,

Thanks for your patch.

On 2021-01-22 12:36:37 +0100, Geert Uytterhoeven wrote:
> Replace the open-coded polling loops by calls to the
> readl_poll_timeout_atomic() helper macro.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>  drivers/soc/renesas/rcar-sysc.c | 33 ++++++++++++++-------------------
>  1 file changed, 14 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/soc/renesas/rcar-sysc.c b/drivers/soc/renesas/rcar-sysc.c
> index a00bb098e1fe7488..4ff2671a699a4a3b 100644
> --- a/drivers/soc/renesas/rcar-sysc.c
> +++ b/drivers/soc/renesas/rcar-sysc.c
> @@ -15,6 +15,7 @@
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/soc/renesas/rcar-sysc.h>
>  
>  #include "rcar-sysc.h"
> @@ -44,13 +45,13 @@
>  #define PWRER_OFFS		0x14	/* Power Shutoff/Resume Error */
>  
>  
> -#define SYSCSR_RETRIES		100
> +#define SYSCSR_TIMEOUT		100
>  #define SYSCSR_DELAY_US		1
>  
>  #define PWRER_RETRIES		100
>  #define PWRER_DELAY_US		1
>  
> -#define SYSCISR_RETRIES		1000
> +#define SYSCISR_TIMEOUT		1000
>  #define SYSCISR_DELAY_US	1
>  
>  #define RCAR_PD_ALWAYS_ON	32	/* Always-on power area */
> @@ -68,7 +69,8 @@ static u32 rcar_sysc_extmask_offs, rcar_sysc_extmask_val;
>  static int rcar_sysc_pwr_on_off(const struct rcar_sysc_ch *sysc_ch, bool on)
>  {
>  	unsigned int sr_bit, reg_offs;
> -	int k;
> +	u32 val;
> +	int ret;
>  
>  	if (on) {
>  		sr_bit = SYSCSR_PONENB;
> @@ -79,13 +81,10 @@ static int rcar_sysc_pwr_on_off(const struct rcar_sysc_ch *sysc_ch, bool on)
>  	}
>  
>  	/* Wait until SYSC is ready to accept a power request */
> -	for (k = 0; k < SYSCSR_RETRIES; k++) {
> -		if (ioread32(rcar_sysc_base + SYSCSR) & BIT(sr_bit))
> -			break;
> -		udelay(SYSCSR_DELAY_US);
> -	}
> -
> -	if (k == SYSCSR_RETRIES)
> +	ret = readl_poll_timeout_atomic(rcar_sysc_base + SYSCSR, val,
> +					val & BIT(sr_bit), SYSCSR_DELAY_US,
> +					SYSCSR_TIMEOUT);
> +	if (ret)
>  		return -EAGAIN;
>  
>  	/* Submit power shutoff or power resume request */
> @@ -101,8 +100,7 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
>  	unsigned int chan_mask = BIT(sysc_ch->chan_bit);
>  	unsigned int status;
>  	unsigned long flags;
> -	int ret = 0;
> -	int k;
> +	int k, ret;

nit: I would make k an unsigned as it's now only used in incremental 
loops starting at 0.

With or without this unrelated nit,

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

>  
>  	spin_lock_irqsave(&rcar_sysc_lock, flags);
>  
> @@ -145,13 +143,10 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
>  	}
>  
>  	/* Wait until the power shutoff or resume request has completed * */
> -	for (k = 0; k < SYSCISR_RETRIES; k++) {
> -		if (ioread32(rcar_sysc_base + SYSCISR) & isr_mask)
> -			break;
> -		udelay(SYSCISR_DELAY_US);
> -	}
> -
> -	if (k == SYSCISR_RETRIES)
> +	ret = readl_poll_timeout_atomic(rcar_sysc_base + SYSCISR, status,
> +					status & isr_mask, SYSCISR_DELAY_US,
> +					SYSCISR_TIMEOUT);
> +	if (ret)
>  		ret = -EIO;
>  
>  	iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
> -- 
> 2.25.1
> 

-- 
Regards,
Niklas Söderlund