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Code

rtc-ds1511: 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.  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,update}_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 <anemo@mba.ocn.ne.jp>
Cc: Andrew Sharp <andy.sharp@lsi.com>
Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Atsushi Nemoto 2009-12-15 16:45:58 -08:00 committed by Linus Torvalds
parent a8462ef63c
commit ba4f3e47cb
1 changed files with 60 additions and 88 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

148
drivers/rtc/rtc-ds1511.c
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@ -87,7 +87,6 @@ enum ds1511reg {
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr; /* virtual base address */
unsigned long baseaddr; /* physical base address */
int size; /* amount of memory mapped */
int irq;
unsigned int irqen;
@ -95,6 +94,7 @@ struct rtc_plat_data {
int alrm_min;
int alrm_hour;
int alrm_mday;
spinlock_t lock;
};
static DEFINE_SPINLOCK(ds1511_lock);
@ -302,7 +302,7 @@ ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
{
unsigned long flags;
spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
spin_lock_irqsave(&pdata->lock, flags);
rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
RTC_ALARM_DATE);
@ -317,7 +317,7 @@ ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
RTC_ALARM_SEC);
rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
rtc_read(RTC_CMD1); /* clear interrupts */
spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
spin_unlock_irqrestore(&pdata->lock, flags);
}
static int
@ -362,61 +362,63 @@ ds1511_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
unsigned long events = RTC_IRQF;
unsigned long events = 0;
spin_lock(&pdata->lock);
/*
* read and clear interrupt
*/
if (!(rtc_read(RTC_CMD1) & DS1511_IRQF)) {
return IRQ_NONE;
if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
events = RTC_IRQF;
if (rtc_read(RTC_ALARM_SEC) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
if (likely(pdata->rtc))
rtc_update_irq(pdata->rtc, 1, events);
}
if (rtc_read(RTC_ALARM_SEC) & 0x80) {
events |= RTC_UF;
} else {
events |= RTC_AF;
}
rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
spin_unlock(&pdata->lock);
return events ? IRQ_HANDLED : IRQ_NONE;
}
static int
ds1511_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
static int ds1511_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;
ds1511_rtc_update_alarm(pdata);
break;
case RTC_AIE_ON:
if (pdata->irq <= 0)
return -EINVAL;
if (enabled)
pdata->irqen |= RTC_AF;
ds1511_rtc_update_alarm(pdata);
break;
case RTC_UIE_OFF:
pdata->irqen &= ~RTC_UF;
ds1511_rtc_update_alarm(pdata);
break;
case RTC_UIE_ON:
else
pdata->irqen &= ~RTC_AF;
ds1511_rtc_update_alarm(pdata);
return 0;
}
static int ds1511_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;
ds1511_rtc_update_alarm(pdata);
break;
default:
return -ENOIOCTLCMD;
}
else
pdata->irqen &= ~RTC_UF;
ds1511_rtc_update_alarm(pdata);
return 0;
}
static const struct rtc_class_ops ds1511_rtc_ops = {
.read_time = ds1511_rtc_read_time,
.set_time = ds1511_rtc_set_time,
.read_alarm = ds1511_rtc_read_alarm,
.set_alarm = ds1511_rtc_set_alarm,
.ioctl = ds1511_rtc_ioctl,
.read_time = ds1511_rtc_read_time,
.set_time = ds1511_rtc_set_time,
.read_alarm = ds1511_rtc_read_alarm,
.set_alarm = ds1511_rtc_set_alarm,
.alarm_irq_enable = ds1511_rtc_alarm_irq_enable,
.update_irq_enable = ds1511_rtc_update_irq_enable,
};
static ssize_t
@ -492,29 +494,23 @@ ds1511_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct resource *res;
struct rtc_plat_data *pdata = NULL;
struct rtc_plat_data *pdata;
int ret = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
return -ENODEV;
}
pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
if (!pdata) {
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
}
pdata->size = res->end - res->start + 1;
if (!request_mem_region(res->start, pdata->size, pdev->name)) {
ret = -EBUSY;
goto out;
}
pdata->baseaddr = res->start;
pdata->size = pdata->size;
ds1511_base = ioremap(pdata->baseaddr, pdata->size);
if (!ds1511_base) {
ret = -ENOMEM;
goto out;
}
if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
pdev->name))
return -EBUSY;
ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
if (!ds1511_base)
return -ENOMEM;
pdata->ioaddr = ds1511_base;
pdata->irq = platform_get_irq(pdev, 0);
@ -540,13 +536,15 @@ ds1511_rtc_probe(struct platform_device *pdev)
dev_warn(&pdev->dev, "voltage-low detected.\n");
}
spin_lock_init(&pdata->lock);
platform_set_drvdata(pdev, pdata);
/*
* if the platform has an interrupt in mind for this device,
* then by all means, set it
*/
if (pdata->irq > 0) {
rtc_read(RTC_CMD1);
if (request_irq(pdata->irq, ds1511_interrupt,
if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
@ -556,33 +554,13 @@ ds1511_rtc_probe(struct platform_device *pdev)
rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_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;
platform_set_drvdata(pdev, pdata);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_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 (ds1511_base) {
iounmap(ds1511_base);
ds1511_base = NULL;
}
if (pdata->baseaddr) {
release_mem_region(pdata->baseaddr, pdata->size);
}
kfree(pdata);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
if (ret)
rtc_device_unregister(pdata->rtc);
return ret;
}
@ -593,19 +571,13 @@ ds1511_rtc_remove(struct platform_device *pdev)
sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
rtc_device_unregister(pdata->rtc);
pdata->rtc = NULL;
if (pdata->irq > 0) {
/*
* disable the alarm interrupt
*/
rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
rtc_read(RTC_CMD1);
free_irq(pdata->irq, pdev);
}
iounmap(pdata->ioaddr);
ds1511_base = NULL;
release_mem_region(pdata->baseaddr, pdata->size);
kfree(pdata);
return 0;
}