/*

 * Machine dependent access functions for RTC registers.

 */

#ifndef _ASM_X86_MC146818RTC_H

#define _ASM_X86_MC146818RTC_H

#include <asm/io.h>

#include <asm/system.h>

#include <asm/processor.h>

#include <linux/mc146818rtc.h>

#ifndef RTC_PORT

#define RTC_PORT(x)	(0x70 + (x))

#define RTC_ALWAYS_BCD	1	/* RTC operates in binary mode */

#endif

#if defined(CONFIG_X86_32) && defined(__HAVE_ARCH_CMPXCHG)

/*

 * This lock provides nmi access to the CMOS/RTC registers.  It has some

 * special properties.  It is owned by a CPU and stores the index register

 * currently being accessed (if owned).  The idea here is that it works

 * like a normal lock (normally).  However, in an NMI, the NMI code will

 * first check to see if its CPU owns the lock, meaning that the NMI

 * interrupted during the read/write of the device.  If it does, it goes ahead

 * and performs the access and then restores the index register.  If it does

 * not, it locks normally.

 *

 * Note that since we are working with NMIs, we need this lock even in

 * a non-SMP machine just to mark that the lock is owned.

 *

 * This only works with compare-and-swap.  There is no other way to

 * atomically claim the lock and set the owner.

 */

#include <linux/smp.h>

extern volatile unsigned long cmos_lock;

/*

 * All of these below must be called with interrupts off, preempt

 * disabled, etc.

 */

static inline void lock_cmos(unsigned char reg)

{

	unsigned long new;

	new = ((smp_processor_id() + 1) << 8) | reg;

	for (;;) {

		if (cmos_lock) {

			cpu_relax();

			continue;

		}

		if (__cmpxchg(&cmos_lock, 0, new, sizeof(cmos_lock)) == 0)

			return;

	}

}

static inline void unlock_cmos(void)

{

	cmos_lock = 0;

}

static inline int do_i_have_lock_cmos(void)

{

	return (cmos_lock >> 8) == (smp_processor_id() + 1);

}

static inline unsigned char current_lock_cmos_reg(void)

{

	return cmos_lock & 0xff;

}

#define lock_cmos_prefix(reg)			\

	do {					\

		unsigned long cmos_flags;	\

		local_irq_save(cmos_flags);	\

		lock_cmos(reg)

#define lock_cmos_suffix(reg)			\

	unlock_cmos();				\

	local_irq_restore(cmos_flags);		\

	} while (0)

#else

#define lock_cmos_prefix(reg) do {} while (0)

#define lock_cmos_suffix(reg) do {} while (0)

#define lock_cmos(reg)

#define unlock_cmos()

#define do_i_have_lock_cmos() 0

#define current_lock_cmos_reg() 0

#endif

/*

 * The yet supported machines all access the RTC index register via

 * an ISA port access but the way to access the date register differs ...

 */

#define CMOS_READ(addr) rtc_cmos_read(addr)

#define CMOS_WRITE(val, addr) rtc_cmos_write(val, addr)

unsigned char rtc_cmos_read(unsigned char addr);

void rtc_cmos_write(unsigned char val, unsigned char addr);

extern int mach_set_rtc_mmss(unsigned long nowtime);

extern unsigned long mach_get_cmos_time(void);

#define RTC_IRQ 8

#endif /* _ASM_X86_MC146818RTC_H */