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Subject[PATCH 3/3] rtc-tx4939: Fix races around device registration
From
* Use its own spinlock instead of rtc->irq_lock
* Check pdata->rtc before calling rtc_update_irq
* Disable interrupt after rtc_device_unregister

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
---
drivers/rtc/rtc-tx4939.c | 51 +++++++++++++++++++++++----------------------
1 files changed, 26 insertions(+), 25 deletions(-)
diff --git a/drivers/rtc/rtc-tx4939.c b/drivers/rtc/rtc-tx4939.c
index 4a6ed11..9ee81d8 100644
--- a/drivers/rtc/rtc-tx4939.c
+++ b/drivers/rtc/rtc-tx4939.c
@@ -17,6 +17,7 @@
struct tx4939rtc_plat_data {
struct rtc_device *rtc;
struct tx4939_rtc_reg __iomem *rtcreg;
+ spinlock_t lock;
};

static struct tx4939rtc_plat_data *get_tx4939rtc_plat_data(struct device *dev)
@@ -52,14 +53,14 @@ static int tx4939_rtc_set_mmss(struct device *dev, unsigned long secs)
buf[3] = secs >> 8;
buf[4] = secs >> 16;
buf[5] = secs >> 24;
- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
__raw_writel(0, &rtcreg->adr);
for (i = 0; i < 6; i++)
__raw_writel(buf[i], &rtcreg->dat);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_SETTIME |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return ret;
}

@@ -71,18 +72,18 @@ static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
unsigned long sec;
unsigned char buf[6];

- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_GETTIME |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
if (ret) {
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return ret;
}
__raw_writel(2, &rtcreg->adr);
for (i = 2; i < 6; i++)
buf[i] = __raw_readl(&rtcreg->dat);
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];
rtc_time_to_tm(sec, tm);
return rtc_valid_tm(tm);
@@ -110,13 +111,13 @@ static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
buf[3] = sec >> 8;
buf[4] = sec >> 16;
buf[5] = sec >> 24;
- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
__raw_writel(0, &rtcreg->adr);
for (i = 0; i < 6; i++)
__raw_writel(buf[i], &rtcreg->dat);
ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
(alrm->enabled ? TX4939_RTCCTL_ALME : 0));
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return ret;
}

@@ -129,12 +130,12 @@ static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
unsigned char buf[6];
u32 ctl;

- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
ret = tx4939_rtc_cmd(rtcreg,
TX4939_RTCCTL_COMMAND_GETALARM |
(__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
if (ret) {
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return ret;
}
__raw_writel(2, &rtcreg->adr);
@@ -143,7 +144,7 @@ static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
ctl = __raw_readl(&rtcreg->ctl);
alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];
rtc_time_to_tm(sec, &alrm->time);
return rtc_valid_tm(&alrm->time);
@@ -153,11 +154,11 @@ static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);

- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
tx4939_rtc_cmd(pdata->rtcreg,
TX4939_RTCCTL_COMMAND_NOP |
(enabled ? TX4939_RTCCTL_ALME : 0));
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return 0;
}

@@ -167,13 +168,14 @@ static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
unsigned long events = RTC_IRQF;

- spin_lock(&pdata->rtc->irq_lock);
+ spin_lock(&pdata->lock);
if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
events |= RTC_AF;
tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
}
- spin_unlock(&pdata->rtc->irq_lock);
- rtc_update_irq(pdata->rtc, 1, events);
+ spin_unlock(&pdata->lock);
+ if (likely(pdata->rtc))
+ rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
}

@@ -194,13 +196,13 @@ static ssize_t tx4939_rtc_nvram_read(struct kobject *kobj,
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
ssize_t count;

- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;
count++, size--) {
__raw_writel(pos++, &rtcreg->adr);
*buf++ = __raw_readl(&rtcreg->dat);
}
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return count;
}

@@ -213,13 +215,13 @@ static ssize_t tx4939_rtc_nvram_write(struct kobject *kobj,
struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
ssize_t count;

- spin_lock_irq(&pdata->rtc->irq_lock);
+ spin_lock_irq(&pdata->lock);
for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;
count++, size--) {
__raw_writel(pos++, &rtcreg->adr);
__raw_writel(*buf++, &rtcreg->dat);
}
- spin_unlock_irq(&pdata->rtc->irq_lock);
+ spin_unlock_irq(&pdata->lock);
return count;
}

@@ -259,6 +261,7 @@ static int __init tx4939_rtc_probe(struct platform_device *pdev)
if (!pdata->rtcreg)
return -EBUSY;

+ spin_lock_init(&pdata->lock);
tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
IRQF_DISABLED, pdev->name, &pdev->dev) < 0)
@@ -277,14 +280,12 @@ static int __init tx4939_rtc_probe(struct platform_device *pdev)
static int __exit tx4939_rtc_remove(struct platform_device *pdev)
{
struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
- struct rtc_device *rtc = pdata->rtc;

- spin_lock_irq(&rtc->irq_lock);
- tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
- spin_unlock_irq(&rtc->irq_lock);
sysfs_remove_bin_file(&pdev->dev.kobj, &tx4939_rtc_nvram_attr);
- rtc_device_unregister(rtc);
- platform_set_drvdata(pdev, NULL);
+ rtc_device_unregister(pdata->rtc);
+ spin_lock_irq(&pdata->lock);
+ tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
+ spin_unlock_irq(&pdata->lock);
return 0;
}

--
1.5.6.5



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