arch/c6x/include/asm/delay.h

   1 /*
   2  *  Port on Texas Instruments TMS320C6x architecture
   3  *
   4  *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
   5  *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  */
  11 #ifndef _ASM_C6X_DELAY_H
  12 #define _ASM_C6X_DELAY_H
  13
  14 #include <linux/kernel.h>
  15
  16 extern unsigned int ticks_per_ns_scaled;
  17
  18 static inline void __delay(unsigned long loops)
  19 {
  20         uint32_t tmp;
  21
  22         /* 6 cycles per loop */
  23         asm volatile ("        mv    .s1  %0,%1\n"
  24                       "0: [%1] b     .s1  0b\n"
  25                       "        add   .l1  -6,%0,%0\n"
  26                       "        cmplt .l1  1,%0,%1\n"
  27                       "        nop   3\n"
  28                       : "+a"(loops), "=A"(tmp));
  29 }
  30
  31 static inline void _c6x_tickdelay(unsigned int x)
  32 {
  33         uint32_t cnt, endcnt;
  34
  35         asm volatile ("        mvc   .s2   TSCL,%0\n"
  36                       "        add   .s2x  %0,%1,%2\n"
  37                       " ||     mvk   .l2   1,B0\n"
  38                       "0: [B0] b     .s2   0b\n"
  39                       "        mvc   .s2   TSCL,%0\n"
  40                       "        sub   .s2   %0,%2,%0\n"
  41                       "        cmpgt .l2   0,%0,B0\n"
  42                       "        nop   2\n"
  43                       : "=b"(cnt), "+a"(x), "=b"(endcnt) : : "B0");
  44 }
  45
  46 /* use scaled math to avoid slow division */
  47 #define C6X_NDELAY_SCALE 10
  48
  49 static inline void _ndelay(unsigned int n)
  50 {
  51         _c6x_tickdelay((ticks_per_ns_scaled * n) >> C6X_NDELAY_SCALE);
  52 }
  53
  54 static inline void _udelay(unsigned int n)
  55 {
  56         while (n >= 10) {
  57                 _ndelay(10000);
  58                 n -= 10;
  59         }
  60         while (n-- > 0)
  61                 _ndelay(1000);
  62 }
  63
  64 #define udelay(x) _udelay((unsigned int)(x))
  65 #define ndelay(x) _ndelay((unsigned int)(x))
  66
  67 #endif /* _ASM_C6X_DELAY_H */