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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/x86_64/lib/delay.c | |
download | lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/x86_64/lib/delay.c')
-rw-r--r-- | arch/x86_64/lib/delay.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86_64/lib/delay.c b/arch/x86_64/lib/delay.c new file mode 100644 index 000000000000..6e2d66472eb1 --- /dev/null +++ b/arch/x86_64/lib/delay.c @@ -0,0 +1,48 @@ +/* + * Precise Delay Loops for x86-64 + * + * 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. + */ + +#include <linux/config.h> +#include <linux/sched.h> +#include <linux/delay.h> +#include <asm/delay.h> + +#ifdef CONFIG_SMP +#include <asm/smp.h> +#endif + +int x86_udelay_tsc = 0; /* Delay via TSC */ + +void __delay(unsigned long loops) +{ + unsigned bclock, now; + + rdtscl(bclock); + do + { + rep_nop(); + rdtscl(now); + } + while((now-bclock) < loops); +} + +inline void __const_udelay(unsigned long xloops) +{ + __delay(((xloops * cpu_data[_smp_processor_id()].loops_per_jiffy) >> 32) * HZ); +} + +void __udelay(unsigned long usecs) +{ + __const_udelay(usecs * 0x000010c6); /* 2**32 / 1000000 */ +} + +void __ndelay(unsigned long nsecs) +{ + __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ +} |