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authorJesper Nilsson <jesper.nilsson@axis.com>2008-01-25 11:31:38 -0500
committerJesper Nilsson <jesper.nilsson@axis.com>2008-02-08 05:06:35 -0500
commit48c87a4483d9146d9f23198163d6ee621535702d (patch)
tree1499bd32160b41a5524ee8b44adf41df35fa37ba /arch/cris
parenta474de0a02ee9093af96414a30f69d433201d002 (diff)
CRIS v32: Add precise delay loops for ETRAX FS and ARTPEC-3.
Implements cris_delay10ns.
Diffstat (limited to 'arch/cris')
-rw-r--r--arch/cris/arch-v32/lib/delay.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/cris/arch-v32/lib/delay.c b/arch/cris/arch-v32/lib/delay.c
new file mode 100644
index 000000000000..39f1ac9995b4
--- /dev/null
+++ b/arch/cris/arch-v32/lib/delay.c
@@ -0,0 +1,28 @@
1/*
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);