blob: 39f1ac9995b42b86841aba148b11ddc89c20010c [file] [log] [blame]
Jesper Nilsson48c87a42008-01-25 17:31:38 +01001/*
2 * Precise Delay Loops for ETRAX FS
3 *
4 * Copyright (C) 2006 Axis Communications AB.
5 *
6 */
7
8#include <hwregs/reg_map.h>
9#include <hwregs/reg_rdwr.h>
10#include <hwregs/timer_defs.h>
11#include <linux/types.h>
12#include <linux/delay.h>
13#include <linux/module.h>
14
15/*
16 * On ETRAX FS, we can check the free-running read-only 100MHz timer
17 * getting 32-bit 10ns precision, theoretically good for 42.94967295
18 * seconds. Unsigned arithmetic and careful expression handles
19 * wrapping.
20 */
21
22void cris_delay10ns(u32 n10ns)
23{
24 u32 t0 = REG_RD(timer, regi_timer0, r_time);
25 while (REG_RD(timer, regi_timer0, r_time) - t0 < n10ns)
26 ;
27}
28EXPORT_SYMBOL(cris_delay10ns);