1/* 2 * Machine dependent access functions for RTC registers. 3 */ 4#ifndef _ASM_X86_MC146818RTC_H 5#define _ASM_X86_MC146818RTC_H 6 7#include <asm/io.h> 8#include <asm/system.h> 9#include <asm/processor.h> 10#include <linux/mc146818rtc.h> 11 12#ifndef RTC_PORT 13#define RTC_PORT(x) (0x70 + (x)) 14#define RTC_ALWAYS_BCD 1 /* RTC operates in binary mode */ 15#endif 16 17#if defined(CONFIG_X86_32) && defined(__HAVE_ARCH_CMPXCHG) 18/* 19 * This lock provides nmi access to the CMOS/RTC registers. It has some 20 * special properties. It is owned by a CPU and stores the index register 21 * currently being accessed (if owned). The idea here is that it works 22 * like a normal lock (normally). However, in an NMI, the NMI code will 23 * first check to see if its CPU owns the lock, meaning that the NMI 24 * interrupted during the read/write of the device. If it does, it goes ahead 25 * and performs the access and then restores the index register. If it does 26 * not, it locks normally. 27 * 28 * Note that since we are working with NMIs, we need this lock even in 29 * a non-SMP machine just to mark that the lock is owned. 30 * 31 * This only works with compare-and-swap. There is no other way to 32 * atomically claim the lock and set the owner. 33 */ 34#include <linux/smp.h> 35extern volatile unsigned long cmos_lock; 36 37/* 38 * All of these below must be called with interrupts off, preempt 39 * disabled, etc. 40 */ 41 42static inline void lock_cmos(unsigned char reg) 43{ 44 unsigned long new; 45 new = ((smp_processor_id() + 1) << 8) | reg; 46 for (;;) { 47 if (cmos_lock) { 48 cpu_relax(); 49 continue; 50 } 51 if (__cmpxchg(&cmos_lock, 0, new, sizeof(cmos_lock)) == 0) 52 return; 53 } 54} 55 56static inline void unlock_cmos(void) 57{ 58 cmos_lock = 0; 59} 60 61static inline int do_i_have_lock_cmos(void) 62{ 63 return (cmos_lock >> 8) == (smp_processor_id() + 1); 64} 65 66static inline unsigned char current_lock_cmos_reg(void) 67{ 68 return cmos_lock & 0xff; 69} 70 71#define lock_cmos_prefix(reg) \ 72 do { \ 73 unsigned long cmos_flags; \ 74 local_irq_save(cmos_flags); \ 75 lock_cmos(reg) 76 77#define lock_cmos_suffix(reg) \ 78 unlock_cmos(); \ 79 local_irq_restore(cmos_flags); \ 80 } while (0) 81#else 82#define lock_cmos_prefix(reg) do {} while (0) 83#define lock_cmos_suffix(reg) do {} while (0) 84#define lock_cmos(reg) 85#define unlock_cmos() 86#define do_i_have_lock_cmos() 0 87#define current_lock_cmos_reg() 0 88#endif 89 90/* 91 * The yet supported machines all access the RTC index register via 92 * an ISA port access but the way to access the date register differs ... 93 */ 94#define CMOS_READ(addr) rtc_cmos_read(addr) 95#define CMOS_WRITE(val, addr) rtc_cmos_write(val, addr) 96unsigned char rtc_cmos_read(unsigned char addr); 97void rtc_cmos_write(unsigned char val, unsigned char addr); 98 99extern int mach_set_rtc_mmss(unsigned long nowtime); 100extern unsigned long mach_get_cmos_time(void); 101 102#define RTC_IRQ 8 103 104#endif /* _ASM_X86_MC146818RTC_H */ 105