delay.c 812 B

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  1. // SPDX-License-Identifier: GPL-2.0
  2. // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
  3. #include <linux/kernel.h>
  4. #include <linux/module.h>
  5. #include <linux/init.h>
  6. #include <linux/delay.h>
  7. void __delay(unsigned long loops)
  8. {
  9. asm volatile (
  10. "mov r0, r0\n"
  11. "1:declt %0\n"
  12. "bf 1b"
  13. : "=r"(loops)
  14. : "0"(loops));
  15. }
  16. EXPORT_SYMBOL(__delay);
  17. void __const_udelay(unsigned long xloops)
  18. {
  19. unsigned long long loops;
  20. loops = (unsigned long long)xloops * loops_per_jiffy * HZ;
  21. __delay(loops >> 32);
  22. }
  23. EXPORT_SYMBOL(__const_udelay);
  24. void __udelay(unsigned long usecs)
  25. {
  26. __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
  27. }
  28. EXPORT_SYMBOL(__udelay);
  29. void __ndelay(unsigned long nsecs)
  30. {
  31. __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
  32. }
  33. EXPORT_SYMBOL(__ndelay);