1 /* 2 * Precise Delay Loops for SuperH 3 * 4 * Copyright (C) 1999 Niibe Yutaka & Kaz Kojima 5 */ 6 7 #include <linux/sched.h> 8 #include <linux/delay.h> 9 10 void __delay(unsigned long loops) 11 { 12 __asm__ __volatile__( 13 /* 14 * ST40-300 appears to have an issue with this code, 15 * normally taking two cycles each loop, as with all 16 * other SH variants. If however the branch and the 17 * delay slot straddle an 8 byte boundary, this increases 18 * to 3 cycles. 19 * This align directive ensures this doesn't occur. 20 */ 21 ".balign 8\n\t" 22 23 "tst %0, %0\n\t" 24 "1:\t" 25 "bf/s 1b\n\t" 26 " dt %0" 27 : "=r" (loops) 28 : "0" (loops) 29 : "t"); 30 } 31 32 inline void __const_udelay(unsigned long xloops) 33 { 34 xloops *= 4; 35 __asm__("dmulu.l %0, %2\n\t" 36 "sts mach, %0" 37 : "=r" (xloops) 38 : "0" (xloops), 39 "r" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)) 40 : "macl", "mach"); 41 __delay(++xloops); 42 } 43 44 void __udelay(unsigned long usecs) 45 { 46 __const_udelay(usecs * 0x000010c6); /* 2**32 / 1000000 */ 47 } 48 49 void __ndelay(unsigned long nsecs) 50 { 51 __const_udelay(nsecs * 0x00000005); 52 } 53 54