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linux-next/arch/blackfin/kernel/time.c
Stephen Warren 7b1f62076b 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: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2012-12-24 09:36:07 -07:00

161 lines
3.8 KiB
C

/*
* arch/blackfin/kernel/time.c
*
* This file contains the Blackfin-specific time handling details.
* Most of the stuff is located in the machine specific files.
*
* Copyright 2004-2008 Analog Devices Inc.
* Licensed under the GPL-2 or later.
*/
#include <linux/module.h>
#include <linux/profile.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <asm/blackfin.h>
#include <asm/time.h>
#include <asm/gptimers.h>
/* This is an NTP setting */
#define TICK_SIZE (tick_nsec / 1000)
static struct irqaction bfin_timer_irq = {
.name = "Blackfin Timer Tick",
};
#if defined(CONFIG_IPIPE)
void __init setup_system_timer0(void)
{
/* Power down the core timer, just to play safe. */
bfin_write_TCNTL(0);
disable_gptimers(TIMER0bit);
set_gptimer_status(0, TIMER_STATUS_TRUN0);
while (get_gptimer_status(0) & TIMER_STATUS_TRUN0)
udelay(10);
set_gptimer_config(0, 0x59); /* IRQ enable, periodic, PWM_OUT, SCLKed, OUT PAD disabled */
set_gptimer_period(TIMER0_id, get_sclk() / HZ);
set_gptimer_pwidth(TIMER0_id, 1);
SSYNC();
enable_gptimers(TIMER0bit);
}
#else
void __init setup_core_timer(void)
{
u32 tcount;
/* power up the timer, but don't enable it just yet */
bfin_write_TCNTL(TMPWR);
CSYNC();
/* the TSCALE prescaler counter */
bfin_write_TSCALE(TIME_SCALE - 1);
tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
bfin_write_TPERIOD(tcount);
bfin_write_TCOUNT(tcount);
/* now enable the timer */
CSYNC();
bfin_write_TCNTL(TAUTORLD | TMREN | TMPWR);
}
#endif
static void __init
time_sched_init(irqreturn_t(*timer_routine) (int, void *))
{
#if defined(CONFIG_IPIPE)
setup_system_timer0();
bfin_timer_irq.handler = timer_routine;
setup_irq(IRQ_TIMER0, &bfin_timer_irq);
#else
setup_core_timer();
bfin_timer_irq.handler = timer_routine;
setup_irq(IRQ_CORETMR, &bfin_timer_irq);
#endif
}
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
/*
* Should return useconds since last timer tick
*/
static u32 blackfin_gettimeoffset(void)
{
unsigned long offset;
unsigned long clocks_per_jiffy;
#if defined(CONFIG_IPIPE)
clocks_per_jiffy = bfin_read_TIMER0_PERIOD();
offset = bfin_read_TIMER0_COUNTER() / \
(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);
if ((get_gptimer_status(0) & TIMER_STATUS_TIMIL0) && offset < (100000 / HZ / 2))
offset += (USEC_PER_SEC / HZ);
#else
clocks_per_jiffy = bfin_read_TPERIOD();
offset = (clocks_per_jiffy - bfin_read_TCOUNT()) / \
(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);
/* Check if we just wrapped the counters and maybe missed a tick */
if ((bfin_read_ILAT() & (1 << IRQ_CORETMR))
&& (offset < (100000 / HZ / 2)))
offset += (USEC_PER_SEC / HZ);
#endif
return offset;
}
#endif
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "xtime_update()" routine every clocktick
*/
#ifdef CONFIG_CORE_TIMER_IRQ_L1
__attribute__((l1_text))
#endif
irqreturn_t timer_interrupt(int irq, void *dummy)
{
xtime_update(1);
#ifdef CONFIG_IPIPE
update_root_process_times(get_irq_regs());
#else
update_process_times(user_mode(get_irq_regs()));
#endif
profile_tick(CPU_PROFILING);
return IRQ_HANDLED;
}
void read_persistent_clock(struct timespec *ts)
{
time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
ts->tv_sec = secs_since_1970;
ts->tv_nsec = 0;
}
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
* 2^31 seconds (which uClibc cannot cope with yet)
*/
if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
bfin_write_RTC_STAT(0);
}
#endif
time_sched_init(timer_interrupt);
}