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| author | Max Filippov <jcmvbkbc@gmail.com> | 2014-01-10 09:02:18 +0100 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2014-01-14 21:28:10 +0100 |
| commit | 58f60c222e8d4503a4be654cbd6d4e190dc1a7d8 (patch) | |
| tree | cde29de11e157697767bff7e94de7ea4a712f408 /arch/xtensa | |
| parent | xtensa: enable HAVE_PERF_EVENTS (diff) | |
| download | linux-58f60c222e8d4503a4be654cbd6d4e190dc1a7d8.tar.xz linux-58f60c222e8d4503a4be654cbd6d4e190dc1a7d8.zip | |
xtensa: clean up udelay
Replace division with shift, use ccount_freq instead of loops_per_jiffy.
Introduce __MAX_UDELAY and (undefined) __bad_udelay, break build for too
big udelay constants.
Remove irrelevant comment, clean up code style.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
| -rw-r--r-- | arch/xtensa/include/asm/delay.h | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/arch/xtensa/include/asm/delay.h b/arch/xtensa/include/asm/delay.h index 742b89f3ca2c..69ba4629bed0 100644 --- a/arch/xtensa/include/asm/delay.h +++ b/arch/xtensa/include/asm/delay.h @@ -27,18 +27,27 @@ static inline void __delay(unsigned long loops) : "+r" (loops)); } -/* For SMP/NUMA systems, change boot_cpu_data to something like - * local_cpu_data->... where local_cpu_data points to the current - * cpu. */ +/* Undefined function to get compile-time error */ +void __bad_udelay(void); -static __inline__ void udelay (unsigned long usecs) +#define __MAX_UDELAY 30000 + +static inline void __udelay(unsigned long usecs) { unsigned long start = get_ccount(); - unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ)); + unsigned long cycles = (usecs * (ccount_freq >> 15)) >> 5; /* Note: all variables are unsigned (can wrap around)! */ while (((unsigned long)get_ccount()) - start < cycles) - ; + cpu_relax(); +} + +static inline void udelay(unsigned long usec) +{ + if (__builtin_constant_p(usec) && usec >= __MAX_UDELAY) + __bad_udelay(); + else + __udelay(usec); } #endif |