Subject: Re: [PATCH v1 01/10] clk: at91: pmc: Wait for clocks when resuming
To: Romain Izard <romain.izard.pro@gmail.com>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Wenyou Yang <wenyou.yang@atmel.com>,
        Josh Wu <rainyfeeling@outlook.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
        Thierry Reding <thierry.reding@gmail.com>,
        Richard Genoud <richard.genoud@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alan Stern <stern@rowland.harvard.edu>
CC: <linux-clk@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-iio@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
        <linux-pwm@vger.kernel.org>, <linux-serial@vger.kernel.org>,
        <linux-usb@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
References: <20170908153604.28383-1-romain.izard.pro@gmail.com>
 <20170908153604.28383-2-romain.izard.pro@gmail.com>
From: Nicolas Ferre <nicolas.ferre@microchip.com>
Organization: microchip
Message-ID: <14fb5261-bb03-a6bd-6653-2a2c655b04ee@microchip.com>
Date: Wed, 13 Sep 2017 14:15:30 +0200
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On 08/09/2017 at 17:35, Romain Izard wrote:
> Wait for the syncronization of all clocks when resuming, not only the
> UPLL clock. Do not use regmap_read_poll_timeout, as it will call BUG()
> when interrupts are masked, which is the case in here.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> ---
>  drivers/clk/at91/pmc.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 775af473fe11..5c2b26de303e 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -107,10 +107,20 @@ static int pmc_suspend(void)
>  	return 0;
>  }
>  
> +static bool pmc_ready(unsigned int mask)
> +{
> +	unsigned int status;
> +
> +	regmap_read(pmcreg, AT91_PMC_SR, &status);
> +
> +	return ((status & mask) == mask) ? 1 : 0;
> +}
> +
>  static void pmc_resume(void)
>  {
> -	int i, ret = 0;
> +	int i;
>  	u32 tmp;
> +	u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
>  
>  	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
>  	if (pmc_cache.mckr != tmp)
> @@ -134,13 +144,11 @@ static void pmc_resume(void)
>  			     AT91_PMC_PCR_CMD);
>  	}
>  
> -	if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
> -		ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp,
> -					       !(tmp & AT91_PMC_LOCKU),
> -					       10, 5000);
> -		if (ret)
> -			pr_crit("USB PLL didn't lock when resuming\n");
> -	}
> +	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
> +		mask |= AT91_PMC_LOCKU;
> +
> +	while (!pmc_ready(mask))
> +		cpu_relax();

Okay, but I would prefer to keep the timeout property in it. So we may
need to re-implement a timeout way-out here.

Regards,

>  }
>  
>  static struct syscore_ops pmc_syscore_ops = {
> 


-- 
Nicolas Ferre