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Convert OMAPs 32kHz clocksource implementation to use the generic MMIO

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clocksource support.  This achieves several things:

1. It means we get rid of all these helper functions which frankly should
   never have been necessary.
2. It means omap_readl() inside these helper functions does not appear in
   ftrace output.

Another plus is that we avoid the overhead of calculating the address to
read each time, but a minus is that we use readl() which has a barrier.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[tony@atomide.com: updated to use ioremap]
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Russell King - ARM Linux 2011-07-10 23:05:34 -07:00 committed by Tony Lindgren
parent 727e18b429
commit 354a183f53
2 changed files with 35 additions and 87 deletions
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1
arch/arm/Kconfig
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@ -852,6 +852,7 @@ config ARCH_OMAP
select HAVE_CLK
select ARCH_REQUIRE_GPIOLIB
select ARCH_HAS_CPUFREQ
select CLKSRC_MMIO
select GENERIC_CLOCKEVENTS
select HAVE_SCHED_CLOCK
select ARCH_HAS_HOLES_MEMORYMODEL

121
arch/arm/plat-omap/counter_32k.c
View File

@ -18,6 +18,7 @@
#include <linux/err.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
#include <asm/sched_clock.h>
@ -26,87 +27,16 @@
#include <plat/clock.h>
/*
* 32KHz clocksource ... always available, on pretty most chips except
* OMAP 730 and 1510. Other timers could be used as clocksources, with
* higher resolution in free-running counter modes (e.g. 12 MHz xtal),
* but systems won't necessarily want to spend resources that way.
*/
static void __iomem *timer_32k_base;
#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410
#include <linux/clocksource.h>
/*
* offset_32k holds the init time counter value. It is then subtracted
* from every counter read to achieve a counter that counts time from the
* kernel boot (needed for sched_clock()).
*/
static u32 offset_32k __read_mostly;
#ifdef CONFIG_ARCH_OMAP16XX
static cycle_t notrace omap16xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED) - offset_32k;
}
#else
#define omap16xx_32k_read NULL
#endif
#ifdef CONFIG_SOC_OMAP2420
static cycle_t notrace omap2420_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap2420_32k_read NULL
#endif
#ifdef CONFIG_SOC_OMAP2430
static cycle_t notrace omap2430_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap2430_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP3
static cycle_t notrace omap34xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap34xx_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP4
static cycle_t notrace omap44xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap44xx_32k_read NULL
#endif
/*
* Kernel assumes that sched_clock can be called early but may not have
* things ready yet.
*/
static cycle_t notrace omap_32k_read_dummy(struct clocksource *cs)
{
return 0;
}
static struct clocksource clocksource_32k = {
.name = "32k_counter",
.rating = 250,
.read = omap_32k_read_dummy,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* Returns current time from boot in nsecs. It's OK for this to wrap
* around for now, as it's just a relative time stamp.
@ -122,7 +52,7 @@ static DEFINE_CLOCK_DATA(cd);
static inline unsigned long long notrace _omap_32k_sched_clock(void)
{
u32 cyc = clocksource_32k.read(&clocksource_32k);
u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}
@ -140,7 +70,7 @@ unsigned long long notrace omap_32k_sched_clock(void)
static void notrace omap_update_sched_clock(void)
{
u32 cyc = clocksource_32k.read(&clocksource_32k);
u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
update_sched_clock(&cd, cyc, (u32)~0);
}
@ -153,6 +83,7 @@ static void notrace omap_update_sched_clock(void)
*/
static struct timespec persistent_ts;
static cycles_t cycles, last_cycles;
static unsigned int persistent_mult, persistent_shift;
void read_persistent_clock(struct timespec *ts)
{
unsigned long long nsecs;
@ -160,11 +91,10 @@ void read_persistent_clock(struct timespec *ts)
struct timespec *tsp = &persistent_ts;
last_cycles = cycles;
cycles = clocksource_32k.read(&clocksource_32k);
cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
delta = cycles - last_cycles;
nsecs = clocksource_cyc2ns(delta,
clocksource_32k.mult, clocksource_32k.shift);
nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift);
timespec_add_ns(tsp, nsecs);
*ts = *tsp;
@ -176,29 +106,46 @@ int __init omap_init_clocksource_32k(void)
"%s: can't register clocksource!\n";
if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
u32 pbase;
unsigned long size = SZ_4K;
void __iomem *base;
struct clk *sync_32k_ick;
if (cpu_is_omap16xx())
clocksource_32k.read = omap16xx_32k_read;
else if (cpu_is_omap2420())
clocksource_32k.read = omap2420_32k_read;
if (cpu_is_omap16xx()) {
pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
size = SZ_1K;
} else if (cpu_is_omap2420())
pbase = OMAP2420_32KSYNCT_BASE + 0x10;
else if (cpu_is_omap2430())
clocksource_32k.read = omap2430_32k_read;
pbase = OMAP2430_32KSYNCT_BASE + 0x10;
else if (cpu_is_omap34xx())
clocksource_32k.read = omap34xx_32k_read;
pbase = OMAP3430_32KSYNCT_BASE + 0x10;
else if (cpu_is_omap44xx())
clocksource_32k.read = omap44xx_32k_read;
pbase = OMAP4430_32KSYNCT_BASE + 0x10;
else
return -ENODEV;
/* For this to work we must have a static mapping in io.c for this area */
base = ioremap(pbase, size);
if (!base)
return -ENODEV;
sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
if (!IS_ERR(sync_32k_ick))
clk_enable(sync_32k_ick);
offset_32k = clocksource_32k.read(&clocksource_32k);
timer_32k_base = base;
if (clocksource_register_hz(&clocksource_32k, 32768))
printk(err, clocksource_32k.name);
/*
* 120000 rough estimate from the calculations in
* __clocksource_updatefreq_scale.
*/
clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
32768, NSEC_PER_SEC, 120000);
if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
clocksource_mmio_readl_up))
printk(err, "32k_counter");
init_fixed_sched_clock(&cd, omap_update_sched_clock, 32,
32768, SC_MULT, SC_SHIFT);