2 * (C) Copyright 2000, 2001
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * SPDX-License-Identifier: GPL-2.0+
11 /* ------------------------------------------------------------------------- */
14 * This function is intended for SHORT delays only.
15 * It will overflow at around 10 seconds @ 400MHz,
16 * or 20 seconds @ 200MHz.
18 unsigned long usec2ticks(unsigned long usec)
23 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
25 ticks = ((usec / 10) * (get_tbclk() / 100000));
31 /* ------------------------------------------------------------------------- */
34 * We implement the delay by converting the delay (the number of
35 * microseconds to wait) into a number of time base ticks; then we
36 * watch the time base until it has incremented by that amount.
38 void __udelay(unsigned long usec)
40 ulong ticks = usec2ticks (usec);
44 /* ------------------------------------------------------------------------- */
45 #ifndef CONFIG_NAND_SPL
46 unsigned long ticks2usec(unsigned long ticks)
48 ulong tbclk = get_tbclk();
50 /* usec = ticks * 1000000 / tbclk
51 * Multiplication would overflow at ~4.2e3 ticks,
52 * so we break it up into
53 * usec = ( ( ticks * 1000) / tbclk ) * 1000;
59 return ((ulong)ticks);
62 /* ------------------------------------------------------------------------- */
69 asm volatile("li %0,0 ; mttbl %0 ; mttbu %0;"
74 /* ------------------------------------------------------------------------- */