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powerpc: Don't do generic calibrate_delay() 

Currently we are wasting time calling the generic calibrate_delay()
function. We don't need it since our implementation of __delay() is
based on the CPU timebase. So instead, we use our own small
implementation that initializes loops_per_jiffy to something sensible
to make the few users like spinlock debug be happy

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt 2009-06-09 21:12:00 +00:00
parent 529273c1ad
commit 177996e6e2
2 changed files with 10 additions and 4 deletions
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4
arch/powerpc/Kconfig
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@ -93,10 +93,6 @@ config GENERIC_HWEIGHT
bool bool
default y default y
config GENERIC_CALIBRATE_DELAY
bool
default y
config GENERIC_FIND_NEXT_BIT config GENERIC_FIND_NEXT_BIT
bool bool
default y default y

10
arch/powerpc/kernel/time.c
View File

@ -52,6 +52,7 @@
#include <linux/jiffies.h> #include <linux/jiffies.h>
#include <linux/posix-timers.h> #include <linux/posix-timers.h>
#include <linux/irq.h> #include <linux/irq.h>
#include <linux/delay.h>
#include <asm/io.h> #include <asm/io.h>
#include <asm/processor.h> #include <asm/processor.h>
@ -1143,6 +1144,15 @@ void div128_by_32(u64 dividend_high, u64 dividend_low,
} }
/* We don't need to calibrate delay, we use the CPU timebase for that */
void calibrate_delay(void)
{
/* Some generic code (such as spinlock debug) use loops_per_jiffy
* as the number of __delay(1) in a jiffy, so make it so
*/
loops_per_jiffy = tb_ticks_per_jiffy;
}
static int __init rtc_init(void) static int __init rtc_init(void)
{ {
struct platform_device *pdev; struct platform_device *pdev;