diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:33 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:33 +0200 |
commit | 44f0257fc316ff4b33aa3438dd8d891b7d6d72b9 (patch) | |
tree | c1a9a571db37d631489f18e1dfe5554874b19027 /arch/x86/lib/delay_32.c | |
parent | da957e111bb0c189a4a3bf8a00caaecb59ed94ca (diff) |
i386: move lib
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/delay_32.c')
-rw-r--r-- | arch/x86/lib/delay_32.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c new file mode 100644 index 00000000000..f6edb11364d --- /dev/null +++ b/arch/x86/lib/delay_32.c @@ -0,0 +1,103 @@ +/* + * Precise Delay Loops for i386 + * + * Copyright (C) 1993 Linus Torvalds + * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * + * The __delay function must _NOT_ be inlined as its execution time + * depends wildly on alignment on many x86 processors. The additional + * jump magic is needed to get the timing stable on all the CPU's + * we have to worry about. + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/delay.h> + +#include <asm/processor.h> +#include <asm/delay.h> +#include <asm/timer.h> + +#ifdef CONFIG_SMP +# include <asm/smp.h> +#endif + +/* simple loop based delay: */ +static void delay_loop(unsigned long loops) +{ + int d0; + + __asm__ __volatile__( + "\tjmp 1f\n" + ".align 16\n" + "1:\tjmp 2f\n" + ".align 16\n" + "2:\tdecl %0\n\tjns 2b" + :"=&a" (d0) + :"0" (loops)); +} + +/* TSC based delay: */ +static void delay_tsc(unsigned long loops) +{ + unsigned long bclock, now; + + rdtscl(bclock); + do { + rep_nop(); + rdtscl(now); + } while ((now-bclock) < loops); +} + +/* + * Since we calibrate only once at boot, this + * function should be set once at boot and not changed + */ +static void (*delay_fn)(unsigned long) = delay_loop; + +void use_tsc_delay(void) +{ + delay_fn = delay_tsc; +} + +int read_current_timer(unsigned long *timer_val) +{ + if (delay_fn == delay_tsc) { + rdtscl(*timer_val); + return 0; + } + return -1; +} + +void __delay(unsigned long loops) +{ + delay_fn(loops); +} + +inline void __const_udelay(unsigned long xloops) +{ + int d0; + + xloops *= 4; + __asm__("mull %0" + :"=d" (xloops), "=&a" (d0) + :"1" (xloops), "0" + (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4))); + + __delay(++xloops); +} + +void __udelay(unsigned long usecs) +{ + __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ +} + +void __ndelay(unsigned long nsecs) +{ + __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ +} + +EXPORT_SYMBOL(__delay); +EXPORT_SYMBOL(__const_udelay); +EXPORT_SYMBOL(__udelay); +EXPORT_SYMBOL(__ndelay); |