arch/c6x/include/asm/delay.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  Port on Texas Instruments TMS320C6x architecture
   4  *
   5  *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
   6  *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
   7  */
   8 #ifndef _ASM_C6X_DELAY_H
   9 #define _ASM_C6X_DELAY_H
  10
  11 #include <linux/kernel.h>
  12
  13 extern unsigned int ticks_per_ns_scaled;
  14
  15 static inline void __delay(unsigned long loops)
  16 {
  17         uint32_t tmp;
  18
  19         /* 6 cycles per loop */
  20         asm volatile ("        mv    .s1  %0,%1\n"
  21                       "0: [%1] b     .s1  0b\n"
  22                       "        add   .l1  -6,%0,%0\n"
  23                       "        cmplt .l1  1,%0,%1\n"
  24                       "        nop   3\n"
  25                       : "+a"(loops), "=A"(tmp));
  26 }
  27
  28 static inline void _c6x_tickdelay(unsigned int x)
  29 {
  30         uint32_t cnt, endcnt;
  31
  32         asm volatile ("        mvc   .s2   TSCL,%0\n"
  33                       "        add   .s2x  %0,%1,%2\n"
  34                       " ||     mvk   .l2   1,B0\n"
  35                       "0: [B0] b     .s2   0b\n"
  36                       "        mvc   .s2   TSCL,%0\n"
  37                       "        sub   .s2   %0,%2,%0\n"
  38                       "        cmpgt .l2   0,%0,B0\n"
  39                       "        nop   2\n"
  40                       : "=b"(cnt), "+a"(x), "=b"(endcnt) : : "B0");
  41 }
  42
  43 /* use scaled math to avoid slow division */
  44 #define C6X_NDELAY_SCALE 10
  45
  46 static inline void _ndelay(unsigned int n)
  47 {
  48         _c6x_tickdelay((ticks_per_ns_scaled * n) >> C6X_NDELAY_SCALE);
  49 }
  50
  51 static inline void _udelay(unsigned int n)
  52 {
  53         while (n >= 10) {
  54                 _ndelay(10000);
  55                 n -= 10;
  56         }
  57         while (n-- > 0)
  58                 _ndelay(1000);
  59 }
  60
  61 #define udelay(x) _udelay((unsigned int)(x))
  62 #define ndelay(x) _ndelay((unsigned int)(x))
  63
  64 #endif /* _ASM_C6X_DELAY_H */