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linux/drivers/rtc/rtc-tps65910.c
Thierry Reding 9f7d7a1d0f drivers/rtc/rtc-tps65910.c: fix potential NULL-pointer dereference 
The interrupt handler gets the driver data associated with the RTC
device and doesn't check it for validity.  This can cause a NULL pointer
being dereferenced when and interrupt fires before the driver data was
properly set up.

Fix this by setting the driver data earlier (before the interrupt is
requested).

Signed-off-by: Thierry Reding <treding@nvidia.com>
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>
2014-08-08 15:57:20 -07:00

339 lines
8.6 KiB
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/*
* rtc-tps65910.c -- TPS65910 Real Time Clock interface
*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
* Author: Venu Byravarasu <vbyravarasu@nvidia.com>
*
* Based on original TI driver rtc-twl.c
* Copyright (C) 2007 MontaVista Software, Inc
* Author: Alexandre Rusev <source@mvista.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/mfd/tps65910.h>
struct tps65910_rtc {
struct rtc_device *rtc;
int irq;
};
/* Total number of RTC registers needed to set time*/
#define NUM_TIME_REGS (TPS65910_YEARS - TPS65910_SECONDS + 1)
static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
{
struct tps65910 *tps = dev_get_drvdata(dev->parent);
u8 val = 0;
if (enabled)
val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
}
/*
* Gets current tps65910 RTC time and date parameters.
*
* The RTC's time/alarm representation is not what gmtime(3) requires
* Linux to use:
*
* - Months are 1..12 vs Linux 0-11
* - Years are 0..99 vs Linux 1900..N (we assume 21st century)
*/
static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char rtc_data[NUM_TIME_REGS];
struct tps65910 *tps = dev_get_drvdata(dev->parent);
int ret;
/* Copy RTC counting registers to static registers or latches */
ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
if (ret < 0) {
dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
return ret;
}
ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "reading from RTC failed with err:%d\n", ret);
return ret;
}
tm->tm_sec = bcd2bin(rtc_data[0]);
tm->tm_min = bcd2bin(rtc_data[1]);
tm->tm_hour = bcd2bin(rtc_data[2]);
tm->tm_mday = bcd2bin(rtc_data[3]);
tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
tm->tm_year = bcd2bin(rtc_data[5]) + 100;
return ret;
}
static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char rtc_data[NUM_TIME_REGS];
struct tps65910 *tps = dev_get_drvdata(dev->parent);
int ret;
rtc_data[0] = bin2bcd(tm->tm_sec);
rtc_data[1] = bin2bcd(tm->tm_min);
rtc_data[2] = bin2bcd(tm->tm_hour);
rtc_data[3] = bin2bcd(tm->tm_mday);
rtc_data[4] = bin2bcd(tm->tm_mon + 1);
rtc_data[5] = bin2bcd(tm->tm_year - 100);
/* Stop RTC while updating the RTC time registers */
ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
TPS65910_RTC_CTRL_STOP_RTC, 0);
if (ret < 0) {
dev_err(dev, "RTC stop failed with err:%d\n", ret);
return ret;
}
/* update all the time registers in one shot */
ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "rtc_set_time error %d\n", ret);
return ret;
}
/* Start back RTC */
ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
TPS65910_RTC_CTRL_STOP_RTC, 1);
if (ret < 0)
dev_err(dev, "RTC start failed with err:%d\n", ret);
return ret;
}
/*
* Gets current tps65910 RTC alarm time.
*/
static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char alarm_data[NUM_TIME_REGS];
u32 int_val;
struct tps65910 *tps = dev_get_drvdata(dev->parent);
int ret;
ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
NUM_TIME_REGS);
if (ret < 0) {
dev_err(dev, "rtc_read_alarm error %d\n", ret);
return ret;
}
alm->time.tm_sec = bcd2bin(alarm_data[0]);
alm->time.tm_min = bcd2bin(alarm_data[1]);
alm->time.tm_hour = bcd2bin(alarm_data[2]);
alm->time.tm_mday = bcd2bin(alarm_data[3]);
alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
if (ret < 0)
return ret;
if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
alm->enabled = 1;
return ret;
}
static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned char alarm_data[NUM_TIME_REGS];
struct tps65910 *tps = dev_get_drvdata(dev->parent);
int ret;
ret = tps65910_rtc_alarm_irq_enable(dev, 0);
if (ret)
return ret;
alarm_data[0] = bin2bcd(alm->time.tm_sec);
alarm_data[1] = bin2bcd(alm->time.tm_min);
alarm_data[2] = bin2bcd(alm->time.tm_hour);
alarm_data[3] = bin2bcd(alm->time.tm_mday);
alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
/* update all the alarm registers in one shot */
ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
alarm_data, NUM_TIME_REGS);
if (ret) {
dev_err(dev, "rtc_set_alarm error %d\n", ret);
return ret;
}
if (alm->enabled)
ret = tps65910_rtc_alarm_irq_enable(dev, 1);
return ret;
}
static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
{
struct device *dev = rtc;
unsigned long events = 0;
struct tps65910 *tps = dev_get_drvdata(dev->parent);
struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
int ret;
u32 rtc_reg;
ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
if (ret)
return IRQ_NONE;
if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
events = RTC_IRQF | RTC_AF;
ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
if (ret)
return IRQ_NONE;
/* Notify RTC core on event */
rtc_update_irq(tps_rtc->rtc, 1, events);
return IRQ_HANDLED;
}
static const struct rtc_class_ops tps65910_rtc_ops = {
.read_time = tps65910_rtc_read_time,
.set_time = tps65910_rtc_set_time,
.read_alarm = tps65910_rtc_read_alarm,
.set_alarm = tps65910_rtc_set_alarm,
.alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
};
static int tps65910_rtc_probe(struct platform_device *pdev)
{
struct tps65910 *tps65910 = NULL;
struct tps65910_rtc *tps_rtc = NULL;
int ret;
int irq;
u32 rtc_reg;
tps65910 = dev_get_drvdata(pdev->dev.parent);
tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
GFP_KERNEL);
if (!tps_rtc)
return -ENOMEM;
/* Clear pending interrupts */
ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
if (ret < 0)
return ret;
ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
if (ret < 0)
return ret;
dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
/* Enable RTC digital power domain */
ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
if (ret < 0)
return ret;
rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, tps_rtc);
irq = platform_get_irq(pdev, 0);
if (irq <= 0) {
dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
irq);
return -ENXIO;
}
ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
tps65910_rtc_interrupt, IRQF_TRIGGER_LOW | IRQF_EARLY_RESUME,
dev_name(&pdev->dev), &pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "IRQ is not free.\n");
return ret;
}
tps_rtc->irq = irq;
device_set_wakeup_capable(&pdev->dev, 1);
tps_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&tps65910_rtc_ops, THIS_MODULE);
if (IS_ERR(tps_rtc->rtc)) {
ret = PTR_ERR(tps_rtc->rtc);
dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
return ret;
}
return 0;
}
/*
* Disable tps65910 RTC interrupts.
* Sets status flag to free.
*/
static int tps65910_rtc_remove(struct platform_device *pdev)
{
tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int tps65910_rtc_suspend(struct device *dev)
{
struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(tps_rtc->irq);
return 0;
}
static int tps65910_rtc_resume(struct device *dev)
{
struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(tps_rtc->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
tps65910_rtc_resume);
static struct platform_driver tps65910_rtc_driver = {
.probe = tps65910_rtc_probe,
.remove = tps65910_rtc_remove,
.driver = {
.owner = THIS_MODULE,
.name = "tps65910-rtc",
.pm = &tps65910_rtc_pm_ops,
},
};
module_platform_driver(tps65910_rtc_driver);
MODULE_ALIAS("platform:rtc-tps65910");
MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
MODULE_LICENSE("GPL");
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