linux-kernel - RE: [PATCH v2] alarmtimer: Fix rebind failure

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Date:   Mon, 9 Oct 2023 07:00:34 +0000
From:   Biju Das <biju.das.jz@...renesas.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
CC:     John Stultz <jstultz@...gle.com>, Stephen Boyd <sboyd@...nel.org>,
        Douglas Anderson <dianders@...omium.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Biju Das <biju.das.au@...il.com>,
        "linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>
Subject: RE: [PATCH v2] alarmtimer: Fix rebind failure

Hi all,

Gentle ping. Are we happy with this patch as it fixes re-bind failure on RTC subsystem?

Cheers,
Biju

> From: Biju Das <biju.das.jz@...renesas.com>
> Sent: Friday, September 22, 2023 9:12 AM
> Subject: [PATCH v2] alarmtimer: Fix rebind failure
> 
> The resources allocated in alarmtimer_rtc_add_device() are not freed
> leading to re-bind failure for the endpoint driver. Fix this issue by
> adding alarmtimer_rtc_remove_device().
> 
> Fixes: c79108bd19a8 ("alarmtimer: Make alarmtimer platform device child of
> RTC device")
> Fixes: 7c94caca877b ("alarmtimer: Use wakeup source from alarmtimer
> platform device")
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> ---
> v1->v2:
>  * Add fixes tag.
>  * Replaced the variable rtc_pdev->alarmtimer_pdev
>  * Added the check rtcdev == rtc before unregistering the real alarmtimer.
> Note:
>  This issue is found while adding irq support for built in RTC  found on
> Renesas PMIC RAA215300 device. This issue should present  on all RTC
> drivers which calls device_init_wakeup() in probe().
> ---
>  kernel/time/alarmtimer.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index
> 8d9f13d847f0..04d67de8b1fe 100644
> --- a/kernel/time/alarmtimer.c
> +++ b/kernel/time/alarmtimer.c
> @@ -61,6 +61,7 @@ static DEFINE_SPINLOCK(freezer_delta_lock);
>  /* rtc timer and device for setting alarm wakeups at suspend */
>  static struct rtc_timer		rtctimer;
>  static struct rtc_device	*rtcdev;
> +static struct platform_device	*alarmtimer_pdev;
>  static DEFINE_SPINLOCK(rtcdev_lock);
> 
>  /**
> @@ -109,6 +110,7 @@ static int alarmtimer_rtc_add_device(struct device
> *dev)
>  		}
> 
>  		rtcdev = rtc;
> +		alarmtimer_pdev = pdev;
>  		/* hold a reference so it doesn't go away */
>  		get_device(dev);
>  		pdev = NULL;
> @@ -123,6 +125,22 @@ static int alarmtimer_rtc_add_device(struct device
> *dev)
>  	return ret;
>  }
> 
> +static void alarmtimer_rtc_remove_device(struct device *dev) {
> +	struct rtc_device *rtc = to_rtc_device(dev);
> +
> +	if (rtcdev == rtc) {
> +		module_put(rtc->owner);
> +		if (device_may_wakeup(rtc->dev.parent))
> +			device_init_wakeup(&alarmtimer_pdev->dev, false);
> +
> +		platform_device_unregister(alarmtimer_pdev);
> +		put_device(dev);
> +		alarmtimer_pdev = NULL;
> +		rtcdev = NULL;
> +	}
> +}
> +
>  static inline void alarmtimer_rtc_timer_init(void)  {
>  	rtc_timer_init(&rtctimer, NULL, NULL); @@ -130,6 +148,7 @@ static
> inline void alarmtimer_rtc_timer_init(void)
> 
>  static struct class_interface alarmtimer_rtc_interface = {
>  	.add_dev = &alarmtimer_rtc_add_device,
> +	.remove_dev = &alarmtimer_rtc_remove_device,
>  };
> 
>  static int alarmtimer_rtc_interface_setup(void)
> --
> 2.25.1