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rtc-ds1553: fix races around device registration
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* Call dev_set_drvdata before rtc device creation
* Use its own spinlock instead of rtc->irq_lock
* Check pdata->rtc before calling rtc_update_irq
* Use {alarm,update}_irq_enable and remove ioctl routine
* Use devres APIs and simplify error/remove path

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Atsushi Nemoto authored and Linus Torvalds committed Dec 16, 2009
1 parent af69a18 commit 618161f
Showing 1 changed file with 64 additions and 77 deletions.
141 changes: 64 additions & 77 deletions drivers/rtc/rtc-ds1553.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@
#include <linux/platform_device.h>
#include <linux/io.h>

#define DRV_VERSION "0.2"
#define DRV_VERSION "0.3"

#define RTC_REG_SIZE 0x2000
#define RTC_OFFSET 0x1ff0
Expand Down Expand Up @@ -61,14 +61,14 @@
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
resource_size_t baseaddr;
unsigned long last_jiffies;
int irq;
unsigned int irqen;
int alrm_sec;
int alrm_min;
int alrm_hour;
int alrm_mday;
spinlock_t lock;
};

static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
Expand Down Expand Up @@ -139,7 +139,7 @@ static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
void __iomem *ioaddr = pdata->ioaddr;
unsigned long flags;

spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
spin_lock_irqsave(&pdata->lock, flags);
writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_mday),
ioaddr + RTC_DATE_ALARM);
Expand All @@ -154,7 +154,7 @@ static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
ioaddr + RTC_SECONDS_ALARM);
writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
readb(ioaddr + RTC_FLAGS); /* clear interrupts */
spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
spin_unlock_irqrestore(&pdata->lock, flags);
}

static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
Expand Down Expand Up @@ -194,56 +194,61 @@ static irqreturn_t ds1553_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 ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
static int ds1553_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;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_AIE_ON:
return -EINVAL;
if (enabled)
pdata->irqen |= RTC_AF;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_UIE_OFF:
pdata->irqen &= ~RTC_UF;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_UIE_ON:
else
pdata->irqen &= ~RTC_AF;
ds1553_rtc_update_alarm(pdata);
return 0;
}

static int ds1553_rtc_update_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 -EINVAL;
if (enabled)
pdata->irqen |= RTC_UF;
ds1553_rtc_update_alarm(pdata);
break;
default:
return -ENOIOCTLCMD;
}
else
pdata->irqen &= ~RTC_UF;
ds1553_rtc_update_alarm(pdata);
return 0;
}

static const struct rtc_class_ops ds1553_rtc_ops = {
.read_time = ds1553_rtc_read_time,
.set_time = ds1553_rtc_set_time,
.read_alarm = ds1553_rtc_read_alarm,
.set_alarm = ds1553_rtc_set_alarm,
.ioctl = ds1553_rtc_ioctl,
.read_time = ds1553_rtc_read_time,
.set_time = ds1553_rtc_set_time,
.read_alarm = ds1553_rtc_read_alarm,
.set_alarm = ds1553_rtc_set_alarm,
.alarm_irq_enable = ds1553_rtc_alarm_irq_enable,
.update_irq_enable = ds1553_rtc_update_irq_enable,
};

static ssize_t ds1553_nvram_read(struct kobject *kobj,
Expand Down Expand Up @@ -291,26 +296,23 @@ static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
struct rtc_device *rtc;
struct resource *res;
unsigned int cen, sec;
struct rtc_plat_data *pdata = NULL;
void __iomem *ioaddr = NULL;
struct rtc_plat_data *pdata;
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);

Expand All @@ -326,9 +328,13 @@ static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
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, ds1553_rtc_interrupt,
if (devm_request_irq(&pdev->dev, pdata->irq,
ds1553_rtc_interrupt,
IRQF_DISABLED, pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
Expand All @@ -337,27 +343,13 @@ static int __devinit ds1553_rtc_probe(struct platform_device *pdev)

rtc = rtc_device_register(pdev->name, &pdev->dev,
&ds1553_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
goto out;
}
if (IS_ERR(rtc))
return PTR_ERR(rtc);
pdata->rtc = rtc;
pdata->last_jiffies = jiffies;
platform_set_drvdata(pdev, pdata);

ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
if (ret)
goto out;
return 0;
out:
if (pdata->rtc)
rtc_device_unregister(pdata->rtc);
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);
rtc_device_unregister(rtc);
return ret;
}

Expand All @@ -367,13 +359,8 @@ static int __devexit ds1553_rtc_remove(struct platform_device *pdev)

sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_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;
}

Expand Down

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