root/arch/unicore32/lib/delay.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * linux/arch/unicore32/lib/delay.S
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #include <linux/linkage.h>
  10 #include <asm/assembler.h>
  11 #include <asm/param.h>
  12                 .text
  13 
  14 .LC0:           .word   loops_per_jiffy
  15 .LC1:           .word   (2199023*HZ)>>11
  16 
  17 /*
  18  * r0  <= 2000
  19  * lpj <= 0x01ffffff (max. 3355 bogomips)
  20  * HZ  <= 1000
  21  */
  22 
  23 ENTRY(__udelay)
  24                 ldw     r2, .LC1
  25                 mul     r0, r2, r0
  26 ENTRY(__const_udelay)                           @ 0 <= r0 <= 0x7fffff06
  27                 ldw     r2, .LC0
  28                 ldw     r2, [r2]                @ max = 0x01ffffff
  29                 mov     r0, r0 >> #14           @ max = 0x0001ffff
  30                 mov     r2, r2 >> #10           @ max = 0x00007fff
  31                 mul     r0, r2, r0              @ max = 2^32-1
  32                 mov.a   r0, r0 >> #6
  33                 cmoveq  pc, lr
  34 
  35 /*
  36  * loops = r0 * HZ * loops_per_jiffy / 1000000
  37  *
  38  * Oh, if only we had a cycle counter...
  39  */
  40 
  41 @ Delay routine
  42 ENTRY(__delay)
  43                 sub.a   r0, r0, #2
  44                 bua     __delay
  45                 mov     pc, lr
  46 ENDPROC(__udelay)
  47 ENDPROC(__const_udelay)
  48 ENDPROC(__delay)