LXR linux/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
  13extern unsigned int ticks_per_ns_scaled;
  14
  15static 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
  28static 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
  46static inline void _ndelay(unsigned int n)
  47{
  48        _c6x_tickdelay((ticks_per_ns_scaled * n) >> C6X_NDELAY_SCALE);
  49}
  50
  51static 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 */
  65