104 lines
2.8 KiB
C
Executable file
104 lines
2.8 KiB
C
Executable file
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Machine dependent access functions for RTC registers.
|
|
*/
|
|
#ifndef _ASM_X86_MC146818RTC_H
|
|
#define _ASM_X86_MC146818RTC_H
|
|
|
|
#include <asm/io.h>
|
|
#include <asm/processor.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)
|
|
/*
|
|
* 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) do { } while (0)
|
|
#define unlock_cmos() do { } while (0)
|
|
#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(const struct timespec64 *now);
|
|
extern void mach_get_cmos_time(struct timespec64 *now);
|
|
|
|
#define RTC_IRQ 8
|
|
|
|
#endif /* _ASM_X86_MC146818RTC_H */
|