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linux-next/include/linux/rtc.h
John Stultz f6d5b33125 RTC: Fix early irqs caused by calling rtc_set_alarm too early 
When we register an rtc device at boot, we read the alarm value
in hardware and set the rtc device's aie_timer to that value.

The initial method to do this was to simply call rtc_set_alarm()
with the value read from hardware. However, this may cause problems
as rtc_set_alarm may enable interupts, and the RTC alarm might fire,
which can cause invalid pointer dereferencing since the RTC registration
is not complete.

This patch solves the issue by initializing the rtc_device.aie_timer
y hand via rtc_initialize_alarm(). This avoids any calls to the RTC
hardware which might enable interrupts too early.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-03-29 18:44:05 -07:00

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/*
* Generic RTC interface.
* This version contains the part of the user interface to the Real Time Clock
* service. It is used with both the legacy mc146818 and also EFI
* Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
* from <linux/mc146818rtc.h> to this file for 2.4 kernels.
*
* Copyright (C) 1999 Hewlett-Packard Co.
* Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
*/
#ifndef _LINUX_RTC_H_
#define _LINUX_RTC_H_
/*
* The struct used to pass data via the following ioctl. Similar to the
* struct tm in <time.h>, but it needs to be here so that the kernel
* source is self contained, allowing cross-compiles, etc. etc.
*/
struct rtc_time {
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
int tm_yday;
int tm_isdst;
};
/*
* This data structure is inspired by the EFI (v0.92) wakeup
* alarm API.
*/
struct rtc_wkalrm {
unsigned char enabled; /* 0 = alarm disabled, 1 = alarm enabled */
unsigned char pending; /* 0 = alarm not pending, 1 = alarm pending */
struct rtc_time time; /* time the alarm is set to */
};
/*
* Data structure to control PLL correction some better RTC feature
* pll_value is used to get or set current value of correction,
* the rest of the struct is used to query HW capabilities.
* This is modeled after the RTC used in Q40/Q60 computers but
* should be sufficiently flexible for other devices
*
* +ve pll_value means clock will run faster by
* pll_value*pll_posmult/pll_clock
* -ve pll_value means clock will run slower by
* pll_value*pll_negmult/pll_clock
*/
struct rtc_pll_info {
int pll_ctrl; /* placeholder for fancier control */
int pll_value; /* get/set correction value */
int pll_max; /* max +ve (faster) adjustment value */
int pll_min; /* max -ve (slower) adjustment value */
int pll_posmult; /* factor for +ve correction */
int pll_negmult; /* factor for -ve correction */
long pll_clock; /* base PLL frequency */
};
/*
* ioctl calls that are permitted to the /dev/rtc interface, if
* any of the RTC drivers are enabled.
*/
#define RTC_AIE_ON _IO('p', 0x01) /* Alarm int. enable on */
#define RTC_AIE_OFF _IO('p', 0x02) /* ... off */
#define RTC_UIE_ON _IO('p', 0x03) /* Update int. enable on */
#define RTC_UIE_OFF _IO('p', 0x04) /* ... off */
#define RTC_PIE_ON _IO('p', 0x05) /* Periodic int. enable on */
#define RTC_PIE_OFF _IO('p', 0x06) /* ... off */
#define RTC_WIE_ON _IO('p', 0x0f) /* Watchdog int. enable on */
#define RTC_WIE_OFF _IO('p', 0x10) /* ... off */
#define RTC_ALM_SET _IOW('p', 0x07, struct rtc_time) /* Set alarm time */
#define RTC_ALM_READ _IOR('p', 0x08, struct rtc_time) /* Read alarm time */
#define RTC_RD_TIME _IOR('p', 0x09, struct rtc_time) /* Read RTC time */
#define RTC_SET_TIME _IOW('p', 0x0a, struct rtc_time) /* Set RTC time */
#define RTC_IRQP_READ _IOR('p', 0x0b, unsigned long) /* Read IRQ rate */
#define RTC_IRQP_SET _IOW('p', 0x0c, unsigned long) /* Set IRQ rate */
#define RTC_EPOCH_READ _IOR('p', 0x0d, unsigned long) /* Read epoch */
#define RTC_EPOCH_SET _IOW('p', 0x0e, unsigned long) /* Set epoch */
#define RTC_WKALM_SET _IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/
#define RTC_WKALM_RD _IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/
#define RTC_PLL_GET _IOR('p', 0x11, struct rtc_pll_info) /* Get PLL correction */
#define RTC_PLL_SET _IOW('p', 0x12, struct rtc_pll_info) /* Set PLL correction */
/* interrupt flags */
#define RTC_IRQF 0x80 /* any of the following is active */
#define RTC_PF 0x40
#define RTC_AF 0x20
#define RTC_UF 0x10
#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/interrupt.h>
extern int rtc_month_days(unsigned int month, unsigned int year);
extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
extern int rtc_valid_tm(struct rtc_time *tm);
extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
ktime_t rtc_tm_to_ktime(struct rtc_time tm);
struct rtc_time rtc_ktime_to_tm(ktime_t kt);
#include <linux/device.h>
#include <linux/seq_file.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/timerqueue.h>
#include <linux/workqueue.h>
extern struct class *rtc_class;
/*
* For these RTC methods the device parameter is the physical device
* on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
* was passed to rtc_device_register(). Its driver_data normally holds
* device state, including the rtc_device pointer for the RTC.
*
* Most of these methods are called with rtc_device.ops_lock held,
* through the rtc_*(struct rtc_device *, ...) calls.
*
* The (current) exceptions are mostly filesystem hooks:
* - the proc() hook for procfs
* - non-ioctl() chardev hooks: open(), release(), read_callback()
*
* REVISIT those periodic irq calls *do* have ops_lock when they're
* issued through ioctl() ...
*/
struct rtc_class_ops {
int (*open)(struct device *);
void (*release)(struct device *);
int (*ioctl)(struct device *, unsigned int, unsigned long);
int (*read_time)(struct device *, struct rtc_time *);
int (*set_time)(struct device *, struct rtc_time *);
int (*read_alarm)(struct device *, struct rtc_wkalrm *);
int (*set_alarm)(struct device *, struct rtc_wkalrm *);
int (*proc)(struct device *, struct seq_file *);
int (*set_mmss)(struct device *, unsigned long secs);
int (*read_callback)(struct device *, int data);
int (*alarm_irq_enable)(struct device *, unsigned int enabled);
};
#define RTC_DEVICE_NAME_SIZE 20
typedef struct rtc_task {
void (*func)(void *private_data);
void *private_data;
} rtc_task_t;
struct rtc_timer {
struct rtc_task task;
struct timerqueue_node node;
ktime_t period;
int enabled;
};
/* flags */
#define RTC_DEV_BUSY 0
struct rtc_device
{
struct device dev;
struct module *owner;
int id;
char name[RTC_DEVICE_NAME_SIZE];
const struct rtc_class_ops *ops;
struct mutex ops_lock;
struct cdev char_dev;
unsigned long flags;
unsigned long irq_data;
spinlock_t irq_lock;
wait_queue_head_t irq_queue;
struct fasync_struct *async_queue;
struct rtc_task *irq_task;
spinlock_t irq_task_lock;
int irq_freq;
int max_user_freq;
struct timerqueue_head timerqueue;
struct rtc_timer aie_timer;
struct rtc_timer uie_rtctimer;
struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
int pie_enabled;
struct work_struct irqwork;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
/* Those fields are protected by rtc->irq_lock */
unsigned int oldsecs;
unsigned int uie_irq_active:1;
unsigned int stop_uie_polling:1;
unsigned int uie_task_active:1;
unsigned int uie_timer_active:1;
#endif
};
#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
extern struct rtc_device *rtc_device_register(const char *name,
struct device *dev,
const struct rtc_class_ops *ops,
struct module *owner);
extern void rtc_device_unregister(struct rtc_device *rtc);
extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
extern int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs);
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
extern int rtc_read_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_set_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_initialize_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern void rtc_update_irq(struct rtc_device *rtc,
unsigned long num, unsigned long events);
extern struct rtc_device *rtc_class_open(char *name);
extern void rtc_class_close(struct rtc_device *rtc);
extern int rtc_irq_register(struct rtc_device *rtc,
struct rtc_task *task);
extern void rtc_irq_unregister(struct rtc_device *rtc,
struct rtc_task *task);
extern int rtc_irq_set_state(struct rtc_device *rtc,
struct rtc_task *task, int enabled);
extern int rtc_irq_set_freq(struct rtc_device *rtc,
struct rtc_task *task, int freq);
extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
unsigned int enabled);
void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
void rtc_aie_update_irq(void *private);
void rtc_uie_update_irq(void *private);
enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
int rtc_register(rtc_task_t *task);
int rtc_unregister(rtc_task_t *task);
int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data);
int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
ktime_t expires, ktime_t period);
int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer);
void rtc_timer_do_work(struct work_struct *work);
static inline bool is_leap_year(unsigned int year)
{
return (!(year % 4) && (year % 100)) || !(year % 400);
}
#ifdef CONFIG_RTC_HCTOSYS
extern int rtc_hctosys_ret;
#else
#define rtc_hctosys_ret -ENODEV
#endif
#endif /* __KERNEL__ */
#endif /* _LINUX_RTC_H_ */
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