1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Precise Delay Loops for SuperH 4 * 5 * Copyright (C) 1999 Niibe Yutaka & Kaz Kojima 6 */ 7 8 #include <linux/sched.h> 9 #include <linux/delay.h> 10 11 void __delay(unsigned long loops) 12 { 13 __asm__ __volatile__( 14 /* 15 * ST40-300 appears to have an issue with this code, 16 * normally taking two cycles each loop, as with all 17 * other SH variants. If however the branch and the 18 * delay slot straddle an 8 byte boundary, this increases 19 * to 3 cycles. 20 * This align directive ensures this doesn't occur. 21 */ 22 ".balign 8\n\t" 23 24 "tst %0, %0\n\t" 25 "1:\t" 26 "bf/s 1b\n\t" 27 " dt %0" 28 : "=r" (loops) 29 : "0" (loops) 30 : "t"); 31 } 32 EXPORT_SYMBOL(__delay); 33 34 inline void __const_udelay(unsigned long xloops) 35 { 36 xloops *= 4; 37 __asm__("dmulu.l %0, %2\n\t" 38 "sts mach, %0" 39 : "=r" (xloops) 40 : "0" (xloops), 41 "r" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)) 42 : "macl", "mach"); 43 __delay(++xloops); 44 } 45 46 void __udelay(unsigned long usecs) 47 { 48 __const_udelay(usecs * 0x000010c6); /* 2**32 / 1000000 */ 49 } 50 51 void __ndelay(unsigned long nsecs) 52 { 53 __const_udelay(nsecs * 0x00000005); 54 } 55 56