/* * delay.h - delay functions * * Copyright (c) 2004-2007 Analog Devices Inc. * * Licensed under the GPL-2 or later. */ #ifndef __ASM_DELAY_H__ #define __ASM_DELAY_H__ #include <asm/mach/anomaly.h> 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__ ( "LSETUP(1f, 1f) LC0 = %0;" "1: NOP;" : : "a" (loops) : "LT0", "LB0", "LC0" ); } #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) */ static inline void udelay(unsigned long usecs) { extern unsigned long loops_per_jiffy; __delay(usecs * loops_per_jiffy / (1000000 / HZ)); } #endif