arch/x86/include/asm/mc146818rtc.h

Source file repositories/reference/linux-study-clean/arch/x86/include/asm/mc146818rtc.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/mc146818rtc.h
Extension
.h
Size
2836 bytes
Lines
104
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

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_cmos_time(const struct timespec64 *now);
extern void mach_get_cmos_time(struct timespec64 *now);

#define RTC_IRQ 8

#endif /* _ASM_X86_MC146818RTC_H */

Annotation

Implementation Notes