diff options
Diffstat (limited to 'arch/blackfin/include/asm/delay.h')
| -rw-r--r-- | arch/blackfin/include/asm/delay.h | 35 |
1 files changed, 6 insertions, 29 deletions
diff --git a/arch/blackfin/include/asm/delay.h b/arch/blackfin/include/asm/delay.h index 0889c3abb593..c31f91cc1d5d 100644 --- a/arch/blackfin/include/asm/delay.h +++ b/arch/blackfin/include/asm/delay.h @@ -13,29 +13,7 @@ static inline void __delay(unsigned long loops) { - if (ANOMALY_05000312) { - /* Interrupted loads to loop registers -> bad */ - unsigned long tmp; - __asm__ __volatile__( - "[--SP] = LC0;" - "[--SP] = LT0;" - "[--SP] = LB0;" - "LSETUP (1f,1f) LC0 = %1;" - "1: NOP;" - /* We take advantage of the fact that LC0 is 0 at - * the end of the loop. Otherwise we'd need some - * NOPs after the CLI here. - */ - "CLI %0;" - "LB0 = [SP++];" - "LT0 = [SP++];" - "LC0 = [SP++];" - "STI %0;" - : "=d" (tmp) - : "a" (loops) - ); - } else - __asm__ __volatile__ ( +__asm__ __volatile__ ( "LSETUP(1f, 1f) LC0 = %0;" "1: NOP;" : @@ -47,16 +25,15 @@ static inline void __delay(unsigned long loops) #include <linux/param.h> /* needed for HZ */ /* - * Use only for very small delays ( < 1 msec). Should probably use a - * lookup table, really, as the multiplications take much too long with - * short delays. This is a "reasonable" implementation, though (and the - * first constant multiplications gets optimized away if the delay is - * a constant) + * close approximation borrowed from m68knommu to avoid 64-bit math */ + +#define HZSCALE (268435456 / (1000000/HZ)) + static inline void udelay(unsigned long usecs) { extern unsigned long loops_per_jiffy; - __delay(usecs * loops_per_jiffy / (1000000 / HZ)); + __delay((((usecs * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6); } #endif |