linux/drivers/rtc/rtc-pcap.c
John Stultz 4b3687f9c1 rtc: pcap: Initialize drvdata before registering device
Commit f44f7f96a2 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-05-06 18:02:04 -07:00

222 lines
5.5 KiB
C

/*
* pcap rtc code for Motorola EZX phones
*
* Copyright (c) 2008 guiming zhuo <gmzhuo@gmail.com>
* Copyright (c) 2009 Daniel Ribeiro <drwyrm@gmail.com>
*
* Based on Motorola's rtc.c Copyright (c) 2003-2005 Motorola
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mfd/ezx-pcap.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
struct pcap_rtc {
struct pcap_chip *pcap;
struct rtc_device *rtc;
};
static irqreturn_t pcap_rtc_irq(int irq, void *_pcap_rtc)
{
struct pcap_rtc *pcap_rtc = _pcap_rtc;
unsigned long rtc_events;
if (irq == pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ))
rtc_events = RTC_IRQF | RTC_UF;
else if (irq == pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA))
rtc_events = RTC_IRQF | RTC_AF;
else
rtc_events = 0;
rtc_update_irq(pcap_rtc->rtc, 1, rtc_events);
return IRQ_HANDLED;
}
static int pcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
struct rtc_time *tm = &alrm->time;
unsigned long secs;
u32 tod; /* time of day, seconds since midnight */
u32 days; /* days since 1/1/1970 */
ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_TODA, &tod);
secs = tod & PCAP_RTC_TOD_MASK;
ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_DAYA, &days);
secs += (days & PCAP_RTC_DAY_MASK) * SEC_PER_DAY;
rtc_time_to_tm(secs, tm);
return 0;
}
static int pcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
struct rtc_time *tm = &alrm->time;
unsigned long secs;
u32 tod, days;
rtc_tm_to_time(tm, &secs);
tod = secs % SEC_PER_DAY;
ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_TODA, tod);
days = secs / SEC_PER_DAY;
ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_DAYA, days);
return 0;
}
static int pcap_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
unsigned long secs;
u32 tod, days;
ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_TOD, &tod);
secs = tod & PCAP_RTC_TOD_MASK;
ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_DAY, &days);
secs += (days & PCAP_RTC_DAY_MASK) * SEC_PER_DAY;
rtc_time_to_tm(secs, tm);
return rtc_valid_tm(tm);
}
static int pcap_rtc_set_mmss(struct device *dev, unsigned long secs)
{
struct platform_device *pdev = to_platform_device(dev);
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
u32 tod, days;
tod = secs % SEC_PER_DAY;
ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_TOD, tod);
days = secs / SEC_PER_DAY;
ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_DAY, days);
return 0;
}
static int pcap_rtc_irq_enable(struct device *dev, int pirq, unsigned int en)
{
struct platform_device *pdev = to_platform_device(dev);
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
if (en)
enable_irq(pcap_to_irq(pcap_rtc->pcap, pirq));
else
disable_irq(pcap_to_irq(pcap_rtc->pcap, pirq));
return 0;
}
static int pcap_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
{
return pcap_rtc_irq_enable(dev, PCAP_IRQ_TODA, en);
}
static const struct rtc_class_ops pcap_rtc_ops = {
.read_time = pcap_rtc_read_time,
.read_alarm = pcap_rtc_read_alarm,
.set_alarm = pcap_rtc_set_alarm,
.set_mmss = pcap_rtc_set_mmss,
.alarm_irq_enable = pcap_rtc_alarm_irq_enable,
};
static int __devinit pcap_rtc_probe(struct platform_device *pdev)
{
struct pcap_rtc *pcap_rtc;
int timer_irq, alarm_irq;
int err = -ENOMEM;
pcap_rtc = kmalloc(sizeof(struct pcap_rtc), GFP_KERNEL);
if (!pcap_rtc)
return err;
pcap_rtc->pcap = dev_get_drvdata(pdev->dev.parent);
platform_set_drvdata(pdev, pcap_rtc);
pcap_rtc->rtc = rtc_device_register("pcap", &pdev->dev,
&pcap_rtc_ops, THIS_MODULE);
if (IS_ERR(pcap_rtc->rtc)) {
err = PTR_ERR(pcap_rtc->rtc);
goto fail_rtc;
}
timer_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ);
alarm_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA);
err = request_irq(timer_irq, pcap_rtc_irq, 0, "RTC Timer", pcap_rtc);
if (err)
goto fail_timer;
err = request_irq(alarm_irq, pcap_rtc_irq, 0, "RTC Alarm", pcap_rtc);
if (err)
goto fail_alarm;
return 0;
fail_alarm:
free_irq(timer_irq, pcap_rtc);
fail_timer:
rtc_device_unregister(pcap_rtc->rtc);
fail_rtc:
platform_set_drvdata(pdev, NULL);
kfree(pcap_rtc);
return err;
}
static int __devexit pcap_rtc_remove(struct platform_device *pdev)
{
struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
free_irq(pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ), pcap_rtc);
free_irq(pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA), pcap_rtc);
rtc_device_unregister(pcap_rtc->rtc);
kfree(pcap_rtc);
return 0;
}
static struct platform_driver pcap_rtc_driver = {
.remove = __devexit_p(pcap_rtc_remove),
.driver = {
.name = "pcap-rtc",
.owner = THIS_MODULE,
},
};
static int __init rtc_pcap_init(void)
{
return platform_driver_probe(&pcap_rtc_driver, pcap_rtc_probe);
}
static void __exit rtc_pcap_exit(void)
{
platform_driver_unregister(&pcap_rtc_driver);
}
module_init(rtc_pcap_init);
module_exit(rtc_pcap_exit);
MODULE_DESCRIPTION("Motorola pcap rtc driver");
MODULE_AUTHOR("guiming zhuo <gmzhuo@gmail.com>");
MODULE_LICENSE("GPL");