1 /* 2 * include/asm-xtensa/delay.h 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (C) 2001 - 2005 Tensilica Inc. 9 * 10 */ 11 12 #ifndef _XTENSA_DELAY_H 13 #define _XTENSA_DELAY_H 14 15 #include <asm/timex.h> 16 #include <asm/param.h> 17 18 extern unsigned long loops_per_jiffy; 19 20 static inline void __delay(unsigned long loops) 21 { 22 if (__builtin_constant_p(loops) && loops < 2) 23 __asm__ __volatile__ ("nop"); 24 else if (loops >= 2) 25 /* 2 cycles per loop. */ 26 __asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b" 27 : "+r" (loops)); 28 } 29 30 /* For SMP/NUMA systems, change boot_cpu_data to something like 31 * local_cpu_data->... where local_cpu_data points to the current 32 * cpu. */ 33 34 static __inline__ void udelay (unsigned long usecs) 35 { 36 unsigned long start = get_ccount(); 37 unsigned long cycles = usecs * (loops_per_jiffy / (1000000UL / HZ)); 38 39 /* Note: all variables are unsigned (can wrap around)! */ 40 while (((unsigned long)get_ccount()) - start < cycles) 41 ; 42 } 43 44 #endif 45