forked from Minki/linux
5ab788d738
Drivers should not really include stuff from asm-generic directly, and the PC-style cmos rtc driver does this in order to reuse the mc146818 implementation of get_rtc_time/set_rtc_time rather than the architecture specific one for the architecture it gets built for. To make it more obvious what is going on, this moves and renames the two functions into include/linux/mc146818rtc.h, which holds the other mc146818 specific code. Ideally it would be in a .c file, but that would require extra infrastructure as the functions are called by multiple drivers with conflicting dependencies. With this change, the asm-generic/rtc.h header also becomes much more generic, so it can be reused more easily across any architecture that still relies on the genrtc driver. The only caller of the internal __get_rtc_time/__set_rtc_time functions is in arch/alpha/kernel/rtc.c, and we just change those over to the new naming. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
/*
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* Machine dependent access functions for RTC registers.
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*/
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#ifndef _ASM_X86_MC146818RTC_H
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#define _ASM_X86_MC146818RTC_H
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#include <asm/io.h>
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#include <asm/processor.h>
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#ifndef RTC_PORT
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#define RTC_PORT(x) (0x70 + (x))
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#define RTC_ALWAYS_BCD 1 /* RTC operates in binary mode */
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#endif
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#if defined(CONFIG_X86_32)
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/*
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* This lock provides nmi access to the CMOS/RTC registers. It has some
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* special properties. It is owned by a CPU and stores the index register
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* currently being accessed (if owned). The idea here is that it works
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* like a normal lock (normally). However, in an NMI, the NMI code will
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* first check to see if its CPU owns the lock, meaning that the NMI
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* interrupted during the read/write of the device. If it does, it goes ahead
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* and performs the access and then restores the index register. If it does
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* not, it locks normally.
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*
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* Note that since we are working with NMIs, we need this lock even in
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* a non-SMP machine just to mark that the lock is owned.
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*
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* This only works with compare-and-swap. There is no other way to
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* atomically claim the lock and set the owner.
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*/
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#include <linux/smp.h>
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extern volatile unsigned long cmos_lock;
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/*
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* All of these below must be called with interrupts off, preempt
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* disabled, etc.
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*/
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static inline void lock_cmos(unsigned char reg)
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{
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unsigned long new;
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new = ((smp_processor_id() + 1) << 8) | reg;
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for (;;) {
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if (cmos_lock) {
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cpu_relax();
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continue;
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}
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if (__cmpxchg(&cmos_lock, 0, new, sizeof(cmos_lock)) == 0)
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return;
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}
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}
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static inline void unlock_cmos(void)
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{
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cmos_lock = 0;
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}
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static inline int do_i_have_lock_cmos(void)
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{
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return (cmos_lock >> 8) == (smp_processor_id() + 1);
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}
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static inline unsigned char current_lock_cmos_reg(void)
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{
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return cmos_lock & 0xff;
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}
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#define lock_cmos_prefix(reg) \
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do { \
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unsigned long cmos_flags; \
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local_irq_save(cmos_flags); \
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lock_cmos(reg)
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#define lock_cmos_suffix(reg) \
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unlock_cmos(); \
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local_irq_restore(cmos_flags); \
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} while (0)
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#else
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#define lock_cmos_prefix(reg) do {} while (0)
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#define lock_cmos_suffix(reg) do {} while (0)
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#define lock_cmos(reg) do { } while (0)
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#define unlock_cmos() do { } while (0)
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#define do_i_have_lock_cmos() 0
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#define current_lock_cmos_reg() 0
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#endif
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/*
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* The yet supported machines all access the RTC index register via
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* an ISA port access but the way to access the date register differs ...
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*/
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#define CMOS_READ(addr) rtc_cmos_read(addr)
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#define CMOS_WRITE(val, addr) rtc_cmos_write(val, addr)
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unsigned char rtc_cmos_read(unsigned char addr);
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void rtc_cmos_write(unsigned char val, unsigned char addr);
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extern int mach_set_rtc_mmss(const struct timespec *now);
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extern void mach_get_cmos_time(struct timespec *now);
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#define RTC_IRQ 8
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#endif /* _ASM_X86_MC146818RTC_H */
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