diff options
Diffstat (limited to 'include/asm-x86/mc146818rtc_32.h')
| -rw-r--r-- | include/asm-x86/mc146818rtc_32.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/include/asm-x86/mc146818rtc_32.h b/include/asm-x86/mc146818rtc_32.h new file mode 100644 index 00000000000..1613b42eaf5 --- /dev/null +++ b/include/asm-x86/mc146818rtc_32.h @@ -0,0 +1,97 @@ +/* + * Machine dependent access functions for RTC registers. + */ +#ifndef _ASM_MC146818RTC_H +#define _ASM_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 + +#ifdef __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); + +#define RTC_IRQ 8 + +#endif /* _ASM_MC146818RTC_H */ |