Commit 7b1f6207 authored by Stephen Warren's avatar Stephen Warren
Browse files

time: convert arch_gettimeoffset to a pointer 



Currently, whenever CONFIG_ARCH_USES_GETTIMEOFFSET is enabled, each
arch core provides a single implementation of arch_gettimeoffset(). In
many cases, different sub-architectures, different machines, or
different timer providers exist, and so the arch ends up implementing
arch_gettimeoffset() as a call-through-pointer anyway. Examples are
ARM, Cris, M68K, and it's arguable that the remaining architectures,
M32R and Blackfin, should be doing this anyway.

Modify arch_gettimeoffset so that it itself is a function pointer, which
the arch initializes. This will allow later changes to move the
initialization of this function into individual machine support or timer
drivers. This is particularly useful for code in drivers/clocksource
which should rely on an arch-independant mechanism to register their
implementation of arch_gettimeoffset().

This patch also converts the Cris architecture to set arch_gettimeoffset
directly to the final implementation in time_init(), because Cris already
had separate time_init() functions per sub-architecture. M68K and ARM
are converted to set arch_gettimeoffset to the final implementation in
later patches, because they already have function pointers in place for
this purpose.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: default avatarJohn Stultz <johnstul@us.ibm.com>
Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
parent 547046f2

arch/arm/kernel/time.c

+5 −1
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ EXPORT_SYMBOL(profile_pc); 
#endif



#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET

u32 arch_gettimeoffset(void)

static u32 arm_gettimeoffset(void)

{

	if (system_timer->offset != NULL)

		return system_timer->offset() * 1000;
@@ -164,6 +164,10 @@ device_initcall(timer_init_syscore_ops); 


void __init time_init(void)

{

#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET

	arch_gettimeoffset = arm_gettimeoffset;

#endif



	system_timer = machine_desc->timer;

	system_timer->init();

	sched_clock_postinit();

arch/blackfin/kernel/time.c

+5 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ time_sched_init(irqreturn_t(*timer_routine) (int, void *)) 
/*

 * Should return useconds since last timer tick

 */

u32 arch_gettimeoffset(void)

static u32 blackfin_gettimeoffset(void)

{

	unsigned long offset;

	unsigned long clocks_per_jiffy;
@@ -141,6 +141,10 @@ void read_persistent_clock(struct timespec *ts) 


void __init time_init(void)

{

#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET

	arch_gettimeoffset = blackfin_gettimeoffset;

#endif



#ifdef CONFIG_RTC_DRV_BFIN

	/* [#2663] hack to filter junk RTC values that would cause

	 * userspace to have to deal with time values greater than

arch/cris/arch-v10/kernel/time.c

+4 −2
Original line number Diff line number Diff line
@@ -55,9 +55,9 @@ unsigned long get_ns_in_jiffie(void) 
	return ns;

}



unsigned long do_slow_gettimeoffset(void)

static u32 cris_v10_gettimeoffset(void)

{

	unsigned long count;

	u32 count;



	/* The timer interrupt comes from Etrax timer 0. In order to get

	 * better precision, we check the current value. It might have
@@ -191,6 +191,8 @@ static struct irqaction irq2 = { 
void __init

time_init(void)

{	

	arch_gettimeoffset = cris_v10_gettimeoffset;



	/* probe for the RTC and read it if it exists 

	 * Before the RTC can be probed the loops_per_usec variable needs 

	 * to be initialized to make usleep work. A better value for

arch/cris/kernel/time.c

+0 −11
Original line number Diff line number Diff line
@@ -39,17 +39,6 @@ 
extern unsigned long loops_per_jiffy; /* init/main.c */

unsigned long loops_per_usec;





#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET

extern unsigned long do_slow_gettimeoffset(void);

static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;



u32 arch_gettimeoffset(void)

{

	return do_gettimeoffset();

}

#endif



int set_rtc_mmss(unsigned long nowtime)

{

	D(printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime));

arch/m32r/kernel/time.c

+3 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ extern void smp_local_timer_interrupt(void); 


static unsigned long latch;



u32 arch_gettimeoffset(void)

static u32 m32r_gettimeoffset(void)

{

	unsigned long  elapsed_time = 0;  /* [us] */
@@ -165,6 +165,8 @@ void read_persistent_clock(struct timespec *ts) 


void __init time_init(void)

{

	arch_gettimeoffset = m32r_gettimeoffset;



#if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) \

	|| defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) \

	|| defined(CONFIG_CHIP_OPSP) || defined(CONFIG_CHIP_M32104)

CRA Git | Maintained and supported by SUSTech CRA and CCSE