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powerpc: Fix delay functions for 601 processors

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My earlier merge of delay.h introduced a timebase-based udelay for
32-bit machines but also broke the 601, which doesn't have the
timebase register.  This fixes it by using the 601's RTC register on
the 601, and also moves __delay() and udelay() to be out-of-line in
arch/powerpc/kernel/time.c.  These functions aren't really performance
critical, after all.

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2005-11-18 13:44:17 +11:00
parent fe7bce5ef7
commit 6defa38b37
3 changed files with 30 additions and 46 deletions
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8
arch/powerpc/kernel/misc_32.S
View file

@ -27,14 +27,6 @@
.text
.align 5
_GLOBAL(__delay)
cmpwi 0,r3,0
mtctr r3
beqlr
1: bdnz 1b
blr
/*
* This returns the high 64 bits of the product of two 64-bit numbers.
*/

28
arch/powerpc/kernel/time.c
View file

@ -130,6 +130,34 @@ unsigned long tb_last_stamp;
*/
DEFINE_PER_CPU(unsigned long, last_jiffy);
void __delay(unsigned long loops)
{
unsigned long start;
int diff;
if (__USE_RTC()) {
start = get_rtcl();
do {
/* the RTCL register wraps at 1000000000 */
diff = get_rtcl() - start;
if (diff < 0)
diff += 1000000000;
} while (diff < loops);
} else {
start = get_tbl();
while (get_tbl() - start < loops)
HMT_low();
HMT_medium();
}
}
EXPORT_SYMBOL(__delay);
void udelay(unsigned long usecs)
{
__delay(tb_ticks_per_usec * usecs);
}
EXPORT_SYMBOL(udelay);
static __inline__ void timer_check_rtc(void)
{
/*

40
include/asm-powerpc/delay.h
View file

@ -13,43 +13,7 @@
* Anton Blanchard.
*/
extern unsigned long tb_ticks_per_usec;
#ifdef CONFIG_PPC64
/* define these here to prevent circular dependencies */
/* these instructions control the thread priority on multi-threaded cpus */
#define __HMT_low() asm volatile("or 1,1,1")
#define __HMT_medium() asm volatile("or 2,2,2")
#else
#define __HMT_low()
#define __HMT_medium()
#endif
#define __barrier() asm volatile("" ::: "memory")
static inline unsigned long __get_tb(void)
{
unsigned long rval;
asm volatile("mftb %0" : "=r" (rval));
return rval;
}
static inline void __delay(unsigned long loops)
{
unsigned long start = __get_tb();
while((__get_tb() - start) < loops)
__HMT_low();
__HMT_medium();
__barrier();
}
static inline void udelay(unsigned long usecs)
{
unsigned long loops = tb_ticks_per_usec * usecs;
__delay(loops);
}
extern void __delay(unsigned long loops);
extern void udelay(unsigned long usecs);
#endif /* _ASM_POWERPC_DELAY_H */