[rtc-linux] Re: [PATCH 2/2] rtc: asm9260: rework locking
On 31/08/2016 at 17:14:27 +0200, Oleksij Rempel wrote :
> Hi
>
> Am 31.08.2016 um 02:18 schrieb Alexandre Belloni:
> > The rtc-asm9260 driver uses a discrete spinlock (wrongly uninitialized).
> > Use the rtc mutex to lock mmio accesses instead.
> >
> > Signed-off-by: Alexandre Belloni
> > ---
> > drivers/rtc/rtc-asm9260.c | 16 ++--
> > 1 file changed, 2 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-asm9260.c b/drivers/rtc/rtc-asm9260.c
> > index 5219916ce11d..812f131da694 100644
> > --- a/drivers/rtc/rtc-asm9260.c
> > +++ b/drivers/rtc/rtc-asm9260.c
> > @@ -112,8 +112,6 @@ struct asm9260_rtc_priv {
> > void __iomem*iobase;
> > struct rtc_device *rtc;
> > struct clk *clk;
> > - /* io lock */
> > - spinlock_t lock;
> > };
> >
> > static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
> > @@ -122,11 +120,13 @@ static irqreturn_t asm9260_rtc_irq(int irq, void
> > *dev_id)
> > u32 isr;
> > unsigned long events = 0;
> >
> > + mutex_lock(&priv->rtc->ops_lock);
> > isr = ioread32(priv->iobase + HW_CIIR);
> > if (!isr)
> > return IRQ_NONE;
> >
> > iowrite32(0, priv->iobase + HW_CIIR);
> > + mutex_unlock(&priv->rtc->ops_lock);
>
> This means if we have shared or spurious interrupt we will get a
> deadlock here?
>
True, I'll fix that. I actually got it right at first and then I toyed
with sparse/smatch to see whether it was properly checking the locking.
Seems like my setup was not correct. Thanks for the review !
>
> > events |= RTC_AF | RTC_IRQF;
> >
> > @@ -139,9 +139,7 @@ static int asm9260_rtc_read_time(struct device *dev,
> > struct rtc_time *tm)
> > {
> > struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> > u32 ctime0, ctime1, ctime2;
> > - unsigned long irq_flags;
> >
> > - spin_lock_irqsave(&priv->lock, irq_flags);
> > ctime0 = ioread32(priv->iobase + HW_CTIME0);
> > ctime1 = ioread32(priv->iobase + HW_CTIME1);
> > ctime2 = ioread32(priv->iobase + HW_CTIME2);
> > @@ -155,7 +153,6 @@ static int asm9260_rtc_read_time(struct device *dev,
> > struct rtc_time *tm)
> > ctime1 = ioread32(priv->iobase + HW_CTIME1);
> > ctime2 = ioread32(priv->iobase + HW_CTIME2);
> > }
> > - spin_unlock_irqrestore(&priv->lock, irq_flags);
> >
> > tm->tm_sec = (ctime0 >> BM_CTIME0_SEC_S) & BM_CTIME0_SEC_M;
> > tm->tm_min = (ctime0 >> BM_CTIME0_MIN_S) & BM_CTIME0_MIN_M;
> > @@ -174,9 +171,7 @@ static int asm9260_rtc_read_time(struct device *dev,
> > struct rtc_time *tm)
> > static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
> > {
> > struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> > - unsigned long irq_flags;
> >
> > - spin_lock_irqsave(&priv->lock, irq_flags);
> > /*
> > * make sure SEC counter will not flip other counter on write time,
> > * real value will be written at the enf of sequence.
> > @@ -191,7 +186,6 @@ static int asm9260_rtc_set_time(struct device *dev,
> > struct rtc_time *tm)
> > iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
> > iowrite32(tm->tm_min, priv->iobase + HW_MIN);
> > iowrite32(tm->tm_sec, priv->iobase + HW_SEC);
> > - spin_unlock_irqrestore(&priv->lock, irq_flags);
> >
> > return 0;
> > }
> > @@ -199,9 +193,7 @@ static int asm9260_rtc_set_time(struct device *dev,
> > struct rtc_time *tm)
> > static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm
> > *alrm)
> > {
> > struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> > - unsigned long irq_flags;
> >
> > - spin_lock_irqsave(&priv->lock, irq_flags);
> > alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
> > alrm->time.tm_mon = ioread32(priv->iobase + HW_ALMON);
> > alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
> > @@ -213,7 +205,6 @@ static int asm9260_rtc_read_alarm(struct device *dev,
> > struct rtc_wkalrm *alrm)
> >
> > alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
> > alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
> > - spin_unlock_irqrestore(&priv->lock, irq_flags);
> >
> > return rtc_valid_tm(&alrm->time);
> > }
> > @@ -221,9 +212,7 @@ static int asm9260_rtc_read_alarm(struct device *dev,
> > struct rtc_wkalrm *alrm)
> > static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm
> > *alrm)
> > {
> > struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> > - unsigned long irq_flags;
> >
> > - spin_lock_irqsave(&priv->lock, irq_flags);
> > iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
> > iowrite32(alrm->time.tm_mon, priv->iobase + HW_ALMON);
> > iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
> > @@ -234,7 +223,6 @@ static int asm9260_rtc_set_alarm(struct device *dev,
> > struct rtc_wkalrm *alrm)
> > iowrite32(alrm->time.tm_sec, priv->iobase + HW_ALSEC);
> >
> > iowr
[rtc-linux] Re: [PATCH 2/2] rtc: asm9260: rework locking
Hi
Am 31.08.2016 um 02:18 schrieb Alexandre Belloni:
> The rtc-asm9260 driver uses a discrete spinlock (wrongly uninitialized).
> Use the rtc mutex to lock mmio accesses instead.
>
> Signed-off-by: Alexandre Belloni
> ---
> drivers/rtc/rtc-asm9260.c | 16 ++--
> 1 file changed, 2 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/rtc/rtc-asm9260.c b/drivers/rtc/rtc-asm9260.c
> index 5219916ce11d..812f131da694 100644
> --- a/drivers/rtc/rtc-asm9260.c
> +++ b/drivers/rtc/rtc-asm9260.c
> @@ -112,8 +112,6 @@ struct asm9260_rtc_priv {
> void __iomem*iobase;
> struct rtc_device *rtc;
> struct clk *clk;
> - /* io lock */
> - spinlock_t lock;
> };
>
> static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
> @@ -122,11 +120,13 @@ static irqreturn_t asm9260_rtc_irq(int irq, void
> *dev_id)
> u32 isr;
> unsigned long events = 0;
>
> + mutex_lock(&priv->rtc->ops_lock);
> isr = ioread32(priv->iobase + HW_CIIR);
> if (!isr)
> return IRQ_NONE;
>
> iowrite32(0, priv->iobase + HW_CIIR);
> + mutex_unlock(&priv->rtc->ops_lock);
This means if we have shared or spurious interrupt we will get a
deadlock here?
> events |= RTC_AF | RTC_IRQF;
>
> @@ -139,9 +139,7 @@ static int asm9260_rtc_read_time(struct device *dev,
> struct rtc_time *tm)
> {
> struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> u32 ctime0, ctime1, ctime2;
> - unsigned long irq_flags;
>
> - spin_lock_irqsave(&priv->lock, irq_flags);
> ctime0 = ioread32(priv->iobase + HW_CTIME0);
> ctime1 = ioread32(priv->iobase + HW_CTIME1);
> ctime2 = ioread32(priv->iobase + HW_CTIME2);
> @@ -155,7 +153,6 @@ static int asm9260_rtc_read_time(struct device *dev,
> struct rtc_time *tm)
> ctime1 = ioread32(priv->iobase + HW_CTIME1);
> ctime2 = ioread32(priv->iobase + HW_CTIME2);
> }
> - spin_unlock_irqrestore(&priv->lock, irq_flags);
>
> tm->tm_sec = (ctime0 >> BM_CTIME0_SEC_S) & BM_CTIME0_SEC_M;
> tm->tm_min = (ctime0 >> BM_CTIME0_MIN_S) & BM_CTIME0_MIN_M;
> @@ -174,9 +171,7 @@ static int asm9260_rtc_read_time(struct device *dev,
> struct rtc_time *tm)
> static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
> {
> struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> - unsigned long irq_flags;
>
> - spin_lock_irqsave(&priv->lock, irq_flags);
> /*
>* make sure SEC counter will not flip other counter on write time,
>* real value will be written at the enf of sequence.
> @@ -191,7 +186,6 @@ static int asm9260_rtc_set_time(struct device *dev,
> struct rtc_time *tm)
> iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
> iowrite32(tm->tm_min, priv->iobase + HW_MIN);
> iowrite32(tm->tm_sec, priv->iobase + HW_SEC);
> - spin_unlock_irqrestore(&priv->lock, irq_flags);
>
> return 0;
> }
> @@ -199,9 +193,7 @@ static int asm9260_rtc_set_time(struct device *dev,
> struct rtc_time *tm)
> static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm
> *alrm)
> {
> struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> - unsigned long irq_flags;
>
> - spin_lock_irqsave(&priv->lock, irq_flags);
> alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
> alrm->time.tm_mon = ioread32(priv->iobase + HW_ALMON);
> alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
> @@ -213,7 +205,6 @@ static int asm9260_rtc_read_alarm(struct device *dev,
> struct rtc_wkalrm *alrm)
>
> alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
> alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
> - spin_unlock_irqrestore(&priv->lock, irq_flags);
>
> return rtc_valid_tm(&alrm->time);
> }
> @@ -221,9 +212,7 @@ static int asm9260_rtc_read_alarm(struct device *dev,
> struct rtc_wkalrm *alrm)
> static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> {
> struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
> - unsigned long irq_flags;
>
> - spin_lock_irqsave(&priv->lock, irq_flags);
> iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
> iowrite32(alrm->time.tm_mon, priv->iobase + HW_ALMON);
> iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
> @@ -234,7 +223,6 @@ static int asm9260_rtc_set_alarm(struct device *dev,
> struct rtc_wkalrm *alrm)
> iowrite32(alrm->time.tm_sec, priv->iobase + HW_ALSEC);
>
> iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
> - spin_unlock_irqrestore(&priv->lock, irq_flags);
>
> return 0;
> }
>
--
Regards,
Oleksij
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