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-rw-r--r--arch/blackfin/include/asm/delay.h35
1 files changed, 6 insertions, 29 deletions
diff --git a/arch/blackfin/include/asm/delay.h b/arch/blackfin/include/asm/delay.h
index 0889c3abb593..c31f91cc1d5d 100644
--- a/arch/blackfin/include/asm/delay.h
+++ b/arch/blackfin/include/asm/delay.h
@@ -13,29 +13,7 @@
13 13
14static inline void __delay(unsigned long loops) 14static inline void __delay(unsigned long loops)
15{ 15{
16 if (ANOMALY_05000312) { 16__asm__ __volatile__ (
17 /* Interrupted loads to loop registers -> bad */
18 unsigned long tmp;
19 __asm__ __volatile__(
20 "[--SP] = LC0;"
21 "[--SP] = LT0;"
22 "[--SP] = LB0;"
23 "LSETUP (1f,1f) LC0 = %1;"
24 "1: NOP;"
25 /* We take advantage of the fact that LC0 is 0 at
26 * the end of the loop. Otherwise we'd need some
27 * NOPs after the CLI here.
28 */
29 "CLI %0;"
30 "LB0 = [SP++];"
31 "LT0 = [SP++];"
32 "LC0 = [SP++];"
33 "STI %0;"
34 : "=d" (tmp)
35 : "a" (loops)
36 );
37 } else
38 __asm__ __volatile__ (
39 "LSETUP(1f, 1f) LC0 = %0;" 17 "LSETUP(1f, 1f) LC0 = %0;"
40 "1: NOP;" 18 "1: NOP;"
41 : 19 :
@@ -47,16 +25,15 @@ static inline void __delay(unsigned long loops)
47#include <linux/param.h> /* needed for HZ */ 25#include <linux/param.h> /* needed for HZ */
48 26
49/* 27/*
50 * Use only for very small delays ( < 1 msec). Should probably use a 28 * close approximation borrowed from m68knommu to avoid 64-bit math
51 * lookup table, really, as the multiplications take much too long with
52 * short delays. This is a "reasonable" implementation, though (and the
53 * first constant multiplications gets optimized away if the delay is
54 * a constant)
55 */ 29 */
30
31#define HZSCALE (268435456 / (1000000/HZ))
32
56static inline void udelay(unsigned long usecs) 33static inline void udelay(unsigned long usecs)
57{ 34{
58 extern unsigned long loops_per_jiffy; 35 extern unsigned long loops_per_jiffy;
59 __delay(usecs * loops_per_jiffy / (1000000 / HZ)); 36 __delay((((usecs * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6);
60} 37}
61 38
62#endif 39#endif