diff options
| author | Stephen Boyd <sboyd@codeaurora.org> | 2010-12-20 14:20:31 -0800 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@stericsson.com> | 2011-09-19 15:14:40 +0200 |
| commit | 455c58c736507b3cd29d6c107890f936f48edc78 (patch) | |
| tree | 5e667482d3f78430fa10123b6d6fc9682eb9f11a /arch/arm/include | |
| parent | ab9297b12831514794afa9c0d8c78a2773ea45d0 (diff) | |
ARM: Allow machines to override __delay()
Some machines want to implement their own __delay() routine based
on fixed rate timers. Expose functionality to set the __delay()
routine at runtime. This should allow two machines with different
__delay() routines to happily co-exist within the same kernel
with minimal overhead.
Russell expressed concern that using a timer based __delay()
would cause problems when an iomapped device isn't mapped in
prior to a delay call being made (see
http://article.gmane.org/gmane.linux.ports.arm.kernel/78543 for
more info). We can sidestep that issue with this approach since
the __delay() routine _should_ only be pointed to a timer based
delay once the timer has been properly mapped. Up until that
point __delay() and udelay() will use delay_loop() which is
always safe to call.
This patch is inspired by x86's delay.c
Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Change-Id: I269f101b40ba50c2b635dc92d50f6e82bb934b32
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/13563
Tested-by: Mattias WALLIN <mattias.wallin@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Diffstat (limited to 'arch/arm/include')
| -rw-r--r-- | arch/arm/include/asm/delay.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm/include/asm/delay.h b/arch/arm/include/asm/delay.h index ccc5ed573fa..82ef82a417b 100644 --- a/arch/arm/include/asm/delay.h +++ b/arch/arm/include/asm/delay.h @@ -40,5 +40,12 @@ extern void __const_udelay(unsigned long); __const_udelay((n) * ((2199023U*HZ)>>11))) : \ __udelay(n)) +extern void (*delay_fn)(unsigned long); + +static inline void set_delay_fn(void (*fn)(unsigned long)) +{ + delay_fn = fn; +} + #endif /* defined(_ARM_DELAY_H) */ |