On Mon, 2010-09-27 at 20:33 -0700, Stephen Boyd wrote: > Some machines want to implement their own __delay() routine based > on fixed 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. Say "This allows developers to implement their own __delay() ..." > Russell expressed concern that using a timer based __delay() > would cause problems where an iomapped device isn't mapped in > before a delay call was 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 > > Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > Reviewed-by: Saravana Kannan <skannan@xxxxxxxxxxxxxx> > --- > arch/arm/include/asm/delay.h | 2 ++ > arch/arm/lib/delay.c | 21 ++++++++++++++++++--- > 2 files changed, 20 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/include/asm/delay.h b/arch/arm/include/asm/delay.h > index ccc5ed5..7c732b5 100644 > --- a/arch/arm/include/asm/delay.h > +++ b/arch/arm/include/asm/delay.h > @@ -40,5 +40,7 @@ extern void __const_udelay(unsigned long); > __const_udelay((n) * ((2199023U*HZ)>>11))) : \ > __udelay(n)) > > +extern void set_delay_fn(void (*fn)(unsigned long)); > + > #endif /* defined(_ARM_DELAY_H) */ > > diff --git a/arch/arm/lib/delay.c b/arch/arm/lib/delay.c > index 5ee0adc..b307fcc 100644 > --- a/arch/arm/lib/delay.c > +++ b/arch/arm/lib/delay.c > @@ -3,6 +3,8 @@ > * > * Copyright (C) 1995, 1996 Russell King > * Copyright (c) 2010, Code Aurora Forum. All rights reserved. > + * Copyright (C) 1993 Linus Torvalds > + * Copyright (C) 1997 Martin Mares <mj@xxxxxxxxxxxxxxxxxxxxxxxx> Who is Martin Mares? Why are you adding these? Daniel -- Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
