Commit 1bdbdaac authored by Bernhard Walle's avatar Bernhard Walle Committed by Ingo Molnar
Browse files

x86, rtc: make CONFIG_HPET_EMULATE_RTC usable from modules 



enabled, then interrupts don't work for the rtc-cmos driver which results in
RTC_AIE*, RTC_PIE* and RTC_ALM being unusable.  This affects hwclock from
util-linux-ng at least on i386 since that uses RTC_PIE_ON.  (For x86-64, a
polling method is used for unknown reasons.)

This patch series now

  1. export the functions from arch/x86/kernel/hpet.c that the old char/rtc
     driver uses to work around that problem,

  2. makes it possible to compile the old rtc driver as module, while still
     having CONFIG_HPET_EMULATE_RTC enabled and

  3. makes use of the exported functions in (1) in the new rtc-cmos driver.

This patch:

This patch makes the RTC emulation functions in arch/x86/kernel/hpet.c usable
for kernel modules. It

  - exports the functions (EXPORT_SYMBOL_GPL()),
  - adds an interface to register the interrupt callback function
    instead of using only a fixed callback function and
  - replaces the rtc_get_rtc_time() function which depends on
    CONFIG_RTC with a call to get_rtc_time() which is defined in
    include/asm-generic/rtc.h.

The only dependency to CONFIG_RTC is the call to rtc_interrupt() which is
removed by the next patch. After this, there's no (code) dependency of
this functions to CONFIG_RTC=y any more.

Signed-off-by: default avatarBernhard Walle <bwalle@suse.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Robert Picco <Robert.Picco@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 8b2f7fff

arch/x86/kernel/hpet.c

+46 −1
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ int is_hpet_enabled(void) 
{

	return is_hpet_capable() && hpet_legacy_int_enabled;

}

EXPORT_SYMBOL_GPL(is_hpet_enabled);



/*

 * When the hpet driver (/dev/hpet) is enabled, we need to reserve
@@ -475,6 +476,7 @@ void hpet_disable(void) 
 */

#include <linux/mc146818rtc.h>

#include <linux/rtc.h>

#include <asm/rtc.h>



#define DEFAULT_RTC_INT_FREQ	64

#define DEFAULT_RTC_SHIFT	6
@@ -489,6 +491,38 @@ static unsigned long hpet_default_delta; 
static unsigned long hpet_pie_delta;

static unsigned long hpet_pie_limit;



static rtc_irq_handler irq_handler;



/*

 * Registers a IRQ handler.

 */

int hpet_register_irq_handler(rtc_irq_handler handler)

{

	if (!is_hpet_enabled())

		return -ENODEV;

	if (irq_handler)

		return -EBUSY;



	irq_handler = handler;



	return 0;

}

EXPORT_SYMBOL_GPL(hpet_register_irq_handler);



/*

 * Deregisters the IRQ handler registered with hpet_register_irq_handler()

 * and does cleanup.

 */

void hpet_unregister_irq_handler(rtc_irq_handler handler)

{

	if (!is_hpet_enabled())

		return;



	irq_handler = NULL;

	hpet_rtc_flags = 0;

}

EXPORT_SYMBOL_GPL(hpet_unregister_irq_handler);



/*

 * Timer 1 for RTC emulation. We use one shot mode, as periodic mode

 * is not supported by all HPET implementations for timer 1.
@@ -530,6 +564,7 @@ int hpet_rtc_timer_init(void) 


	return 1;

}

EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);



/*

 * The functions below are called from rtc driver.
@@ -544,6 +579,7 @@ int hpet_mask_rtc_irq_bit(unsigned long bit_mask) 
	hpet_rtc_flags &= ~bit_mask;

	return 1;

}

EXPORT_SYMBOL_GPL(hpet_mask_rtc_irq_bit);



int hpet_set_rtc_irq_bit(unsigned long bit_mask)

{
@@ -559,6 +595,7 @@ int hpet_set_rtc_irq_bit(unsigned long bit_mask) 


	return 1;

}

EXPORT_SYMBOL_GPL(hpet_set_rtc_irq_bit);



int hpet_set_alarm_time(unsigned char hrs, unsigned char min,

			unsigned char sec)
@@ -572,6 +609,7 @@ int hpet_set_alarm_time(unsigned char hrs, unsigned char min, 


	return 1;

}

EXPORT_SYMBOL_GPL(hpet_set_alarm_time);



int hpet_set_periodic_freq(unsigned long freq)

{
@@ -590,11 +628,13 @@ int hpet_set_periodic_freq(unsigned long freq) 
	}

	return 1;

}

EXPORT_SYMBOL_GPL(hpet_set_periodic_freq);



int hpet_rtc_dropped_irq(void)

{

	return is_hpet_enabled();

}

EXPORT_SYMBOL_GPL(hpet_rtc_dropped_irq);



static void hpet_rtc_timer_reinit(void)

{
@@ -638,9 +678,10 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) 
	unsigned long rtc_int_flag = 0;



	hpet_rtc_timer_reinit();

	memset(&curr_time, 0, sizeof(struct rtc_time));



	if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))

		rtc_get_rtc_time(&curr_time);

		get_rtc_time(&curr_time);



	if (hpet_rtc_flags & RTC_UIE &&

	    curr_time.tm_sec != hpet_prev_update_sec) {
@@ -662,8 +703,12 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) 


	if (rtc_int_flag) {

		rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));

		if (irq_handler)

			irq_handler(rtc_int_flag, dev_id);



		rtc_interrupt(rtc_int_flag, dev_id);

	}

	return IRQ_HANDLED;

}

EXPORT_SYMBOL_GPL(hpet_rtc_interrupt);

#endif

include/asm-x86/hpet.h

+3 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ extern void force_hpet_resume(void); 


#include <linux/interrupt.h>



typedef irqreturn_t (*rtc_irq_handler)(int interrupt, void *cookie);

extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);

extern int hpet_set_rtc_irq_bit(unsigned long bit_mask);

extern int hpet_set_alarm_time(unsigned char hrs, unsigned char min,
@@ -77,6 +78,8 @@ extern int hpet_set_periodic_freq(unsigned long freq); 
extern int hpet_rtc_dropped_irq(void);

extern int hpet_rtc_timer_init(void);

extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);

extern int hpet_register_irq_handler(rtc_irq_handler handler);

extern void hpet_unregister_irq_handler(rtc_irq_handler handler);



#endif /* CONFIG_HPET_EMULATE_RTC */

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