From af69a180e0675ce95842adb519079204ee5647ea Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Tue, 15 Dec 2009 16:46:00 -0800 Subject: [PATCH] rtc-tx4939: fix races around device registration * 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 Acked-by: Alessandro Zummo Cc: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-tx4939.c | 51 ++++++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/drivers/rtc/rtc-tx4939.c b/drivers/rtc/rtc-tx4939.c index 4a6ed1104fb..9ee81d8aa7c 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; }