diff options
| author | Aaro Koskinen <aaro.koskinen@nokia.com> | 2010-04-07 13:57:22 +0400 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2010-04-23 04:32:36 +0400 |
| commit | 2decb12e3ebec556520dd92178572449af8ed617 (patch) | |
| tree | 53eb4aa1479fff629c1b9005ad6b602d0e8e044a /arch/arm/plat-omap/common.c | |
| parent | e2bca7c76a79b68506bfc3699beb74c0d41fe230 (diff) | |
| download | linux-2decb12e3ebec556520dd92178572449af8ed617.tar.xz | |
omap: fix clocksource_32k to start from zero
When the 32k sync timer is used for sched_clock(), it should count
time from the kernel boot (clocksource init) instead of the last HW
reset. Otherwise printk.time values will jump suddenly during the boot:
[ 0.000000] calling omap2_clk_arch_init+0x0/0x138 @ 1
[ 0.000000] initcall omap2_clk_arch_init+0x0/0x138 returned -22 after 0 usecs
[ 0.000000] initcall omap2_clk_arch_init+0x0/0x138 returned with error code -22
[ 0.000000] calling omap_init_clocksource_32k+0x0/0x98 @ 1
[ 508.697937] initcall omap_init_clocksource_32k+0x0/0x98 returned 0 after 0 usecs
[ 508.697967] calling omap_init_devices+0x0/0x38 @ 1
[ 508.698425] initcall omap_init_devices+0x0/0x38 returned 0 after 0 usecs
This will confuse tools such as scripts/bootgraph.pl.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm/plat-omap/common.c')
| -rw-r--r-- | arch/arm/plat-omap/common.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c index 088c1a03b946..01cbb48442ac 100644 --- a/arch/arm/plat-omap/common.c +++ b/arch/arm/plat-omap/common.c @@ -100,10 +100,17 @@ EXPORT_SYMBOL(omap_get_var_config); #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 omap16xx_32k_read(struct clocksource *cs) { - return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED); + return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED) - offset_32k; } #else #define omap16xx_32k_read NULL @@ -112,7 +119,7 @@ static cycle_t omap16xx_32k_read(struct clocksource *cs) #ifdef CONFIG_ARCH_OMAP2420 static cycle_t omap2420_32k_read(struct clocksource *cs) { - return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10); + return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10) - offset_32k; } #else #define omap2420_32k_read NULL @@ -121,7 +128,7 @@ static cycle_t omap2420_32k_read(struct clocksource *cs) #ifdef CONFIG_ARCH_OMAP2430 static cycle_t omap2430_32k_read(struct clocksource *cs) { - return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10); + return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10) - offset_32k; } #else #define omap2430_32k_read NULL @@ -130,7 +137,7 @@ static cycle_t omap2430_32k_read(struct clocksource *cs) #ifdef CONFIG_ARCH_OMAP3 static cycle_t omap34xx_32k_read(struct clocksource *cs) { - return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10); + return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10) - offset_32k; } #else #define omap34xx_32k_read NULL @@ -139,7 +146,7 @@ static cycle_t omap34xx_32k_read(struct clocksource *cs) #ifdef CONFIG_ARCH_OMAP4 static cycle_t omap44xx_32k_read(struct clocksource *cs) { - return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10); + return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10) - offset_32k; } #else #define omap44xx_32k_read NULL @@ -227,6 +234,8 @@ static int __init omap_init_clocksource_32k(void) clocksource_32k.mult = clocksource_hz2mult(32768, clocksource_32k.shift); + offset_32k = clocksource_32k.read(&clocksource_32k); + if (clocksource_register(&clocksource_32k)) printk(err, clocksource_32k.name); } |