From: Atsushi Nemoto Date: Wed, 16 Dec 2009 00:46:04 +0000 (-0800) Subject: rtc-stk17ta8: fix races around device registration X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3151520d88b27b9dd4fb1c1f89a94807f0ad7ef1;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git rtc-stk17ta8: fix races around device registration - Call dev_set_drvdata before rtc device creation. - Use its own spinlock instead of rtc->irq_lock. Because pdata->rtc must be initialized to use the irq_lock (pdata->rtc->irq_lock). There is a small window which rtc methods can be called before pdata->rtc is initialized. And there is no need use the irq_lock to protect hardware registers. The driver's own spinlock shoule be enough. - Check pdata->rtc before calling rtc_update_irq. - Use alarm_irq_enable and remove ioctl routine. - Use devres APIs and simplify error/remove path. These fixes are ported from ds1553 driver and just compile-tested only. Signed-off-by: Atsushi Nemoto Cc: Alessandro Zummo Cc: Thomas Hommel Cc: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/rtc/rtc-stk17ta8.c b/drivers/rtc/rtc-stk17ta8.c index 62c2969436a8..31ea22070e3d 100644 --- a/drivers/rtc/rtc-stk17ta8.c +++ b/drivers/rtc/rtc-stk17ta8.c @@ -62,7 +62,6 @@ struct rtc_plat_data { struct rtc_device *rtc; void __iomem *ioaddr; - unsigned long baseaddr; unsigned long last_jiffies; int irq; unsigned int irqen; @@ -70,6 +69,7 @@ struct rtc_plat_data { int alrm_min; int alrm_hour; int alrm_mday; + spinlock_t lock; }; static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm) @@ -142,7 +142,7 @@ static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) unsigned long irqflags; u8 flags; - spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags); + spin_lock_irqsave(&pdata->lock, irqflags); flags = readb(ioaddr + RTC_FLAGS); writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); @@ -162,7 +162,7 @@ static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); readb(ioaddr + RTC_FLAGS); /* clear interrupts */ writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); - spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags); + spin_unlock_irqrestore(&pdata->lock, irqflags); } static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) @@ -202,48 +202,45 @@ static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) struct platform_device *pdev = dev_id; struct rtc_plat_data *pdata = platform_get_drvdata(pdev); void __iomem *ioaddr = pdata->ioaddr; - unsigned long events = RTC_IRQF; + unsigned long events = 0; + spin_lock(&pdata->lock); /* read and clear interrupt */ - if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF)) - return IRQ_NONE; - if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) - events |= RTC_UF; - else - events |= RTC_AF; - rtc_update_irq(pdata->rtc, 1, events); - return IRQ_HANDLED; + if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { + events = RTC_IRQF; + if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) + events |= RTC_UF; + else + events |= RTC_AF; + if (likely(pdata->rtc)) + rtc_update_irq(pdata->rtc, 1, events); + } + spin_unlock(&pdata->lock); + return events ? IRQ_HANDLED : IRQ_NONE; } -static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd, - unsigned long arg) +static int stk17ta8_rtc_alarm_irq_enable(struct device *dev, + unsigned int enabled) { struct platform_device *pdev = to_platform_device(dev); struct rtc_plat_data *pdata = platform_get_drvdata(pdev); if (pdata->irq <= 0) - return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */ - switch (cmd) { - case RTC_AIE_OFF: - pdata->irqen &= ~RTC_AF; - stk17ta8_rtc_update_alarm(pdata); - break; - case RTC_AIE_ON: + return -EINVAL; + if (enabled) pdata->irqen |= RTC_AF; - stk17ta8_rtc_update_alarm(pdata); - break; - default: - return -ENOIOCTLCMD; - } + else + pdata->irqen &= ~RTC_AF; + stk17ta8_rtc_update_alarm(pdata); return 0; } static const struct rtc_class_ops stk17ta8_rtc_ops = { - .read_time = stk17ta8_rtc_read_time, - .set_time = stk17ta8_rtc_set_time, - .read_alarm = stk17ta8_rtc_read_alarm, - .set_alarm = stk17ta8_rtc_set_alarm, - .ioctl = stk17ta8_rtc_ioctl, + .read_time = stk17ta8_rtc_read_time, + .set_time = stk17ta8_rtc_set_time, + .read_alarm = stk17ta8_rtc_read_alarm, + .set_alarm = stk17ta8_rtc_set_alarm, + .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, }; static ssize_t stk17ta8_nvram_read(struct kobject *kobj, @@ -292,26 +289,22 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) unsigned int cal; unsigned int flags; struct rtc_plat_data *pdata; - void __iomem *ioaddr = NULL; + void __iomem *ioaddr; int ret = 0; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENODEV; - pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; - if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) { - ret = -EBUSY; - goto out; - } - pdata->baseaddr = res->start; - ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE); - if (!ioaddr) { - ret = -ENOMEM; - goto out; - } + if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE, + pdev->name)) + return -EBUSY; + ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE); + if (!ioaddr) + return -ENOMEM; pdata->ioaddr = ioaddr; pdata->irq = platform_get_irq(pdev, 0); @@ -327,9 +320,13 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) dev_warn(&pdev->dev, "voltage-low detected.\n"); + spin_lock_init(&pdata->lock); + pdata->last_jiffies = jiffies; + platform_set_drvdata(pdev, pdata); if (pdata->irq > 0) { writeb(0, ioaddr + RTC_INTERRUPTS); - if (request_irq(pdata->irq, stk17ta8_rtc_interrupt, + if (devm_request_irq(&pdev->dev, pdata->irq, + stk17ta8_rtc_interrupt, IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) { dev_warn(&pdev->dev, "interrupt not available.\n"); @@ -337,30 +334,14 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) } } - pdata->last_jiffies = jiffies; - platform_set_drvdata(pdev, pdata); - pdata->rtc = rtc_device_register(pdev->name, &pdev->dev, &stk17ta8_rtc_ops, THIS_MODULE); - if (IS_ERR(pdata->rtc)) { - ret = PTR_ERR(pdata->rtc); - goto out; - } + if (IS_ERR(pdata->rtc)) + return PTR_ERR(pdata->rtc); ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); - if (ret) { + if (ret) rtc_device_unregister(pdata->rtc); - goto out; - } - return 0; - out: - if (pdata->irq > 0) - free_irq(pdata->irq, pdev); - if (ioaddr) - iounmap(ioaddr); - if (pdata->baseaddr) - release_mem_region(pdata->baseaddr, RTC_REG_SIZE); - kfree(pdata); return ret; } @@ -370,13 +351,8 @@ static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev) sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr); rtc_device_unregister(pdata->rtc); - if (pdata->irq > 0) { + if (pdata->irq > 0) writeb(0, pdata->ioaddr + RTC_INTERRUPTS); - free_irq(pdata->irq, pdev); - } - iounmap(pdata->ioaddr); - release_mem_region(pdata->baseaddr, RTC_REG_SIZE); - kfree(pdata); return 0; }