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ARM: 7538/1: delay: add registration mechanism for delay timer sources

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The current timer-based delay loop relies on the architected timer to
initiate the switch away from the polling-based implementation. This is
unfortunate for platforms without the architected timers but with a
suitable delay source (that is, constant frequency, always powered-up
and ticking as long as the CPUs are online).

This patch introduces a registration mechanism for the delay timer
(which provides an unconditional read_current_timer implementation) and
updates the architected timer code to use the new interface.

Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Jonathan Austin
2012-09-21 18:51:44 +01:00
committed by Russell King
parent a1b2dde704
commit 56942fec06
5 changed files with 43 additions and 24 deletions
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17
arch/arm/kernel/arch_timer.c
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@@ -21,6 +21,7 @@
#include <linux/io.h>
#include <asm/cputype.h>
#include <asm/delay.h>
#include <asm/localtimer.h>
#include <asm/arch_timer.h>
#include <asm/system_info.h>
@@ -39,8 +40,7 @@ enum ppi_nr {
static int arch_timer_ppi[MAX_TIMER_PPI];
static struct clock_event_device __percpu **arch_timer_evt;
extern void init_current_timer_delay(unsigned long freq);
static struct delay_timer arch_delay_timer;
static bool arch_timer_use_virtual = true;
@@ -325,12 +325,9 @@ static cycle_t arch_counter_read(struct clocksource *cs)
return arch_counter_get_cntpct();
}
int read_current_timer(unsigned long *timer_val)
static unsigned long arch_timer_read_current_timer(void)
{
if (!arch_timer_rate)
return -ENXIO;
*timer_val = arch_counter_get_cntpct();
return 0;
return arch_counter_get_cntpct();
}
static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
@@ -441,11 +438,13 @@ static int __init arch_timer_register(void)
arch_timer_global_evt.cpumask = cpumask_of(0);
err = arch_timer_setup(&arch_timer_global_evt);
}
if (err)
goto out_free_irq;
init_current_timer_delay(arch_timer_rate);
/* Use the architected timer for the delay loop. */
arch_delay_timer.read_current_timer = &arch_timer_read_current_timer;
arch_delay_timer.freq = arch_timer_rate;
register_current_timer_delay(&arch_delay_timer);
return 0;
out_free_irq: