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| author | Simon Glass <sjg@chromium.org> | 2016-02-24 09:14:49 -0700 |
|---|---|---|
| committer | Simon Glass <sjg@chromium.org> | 2016-02-26 08:53:10 -0700 |
| commit | c95fec31928d7e2596364ee1d226b52ffd7793f2 (patch) | |
| tree | 07972d661c4ce017dbaa2d5e8ce488717aed6cdd | |
| parent | 4f051824b5c2a6bf8d3114c772676977fb95969a (diff) | |
| download | u-boot-imx-c95fec31928d7e2596364ee1d226b52ffd7793f2.zip u-boot-imx-c95fec31928d7e2596364ee1d226b52ffd7793f2.tar.gz u-boot-imx-c95fec31928d7e2596364ee1d226b52ffd7793f2.tar.bz2 | |
timer: Provide an early timer
In some cases the timer must be accessible before driver model is active.
Examples include when using CONFIG_TRACE to trace U-Boot's execution before
driver model is set up. Enable this option to use an early timer. These
functions must be supported by your timer driver: timer_early_get_count()
and timer_early_get_rate().
Signed-off-by: Simon Glass <sjg@chromium.org>
| -rw-r--r-- | drivers/timer/Kconfig | 10 | ||||
| -rw-r--r-- | include/timer.h | 21 | ||||
| -rw-r--r-- | lib/time.c | 28 |
3 files changed, 52 insertions, 7 deletions
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig index ff65a73..cb18f12 100644 --- a/drivers/timer/Kconfig +++ b/drivers/timer/Kconfig @@ -9,6 +9,16 @@ config TIMER will be used. The timer is usually a 32 bits free-running up counter. There may be no real tick, and no timer interrupt. +config TIMER_EARLY + bool "Allow timer to be used early in U-Boot" + depends on TIMER + help + In some cases the timer must be accessible before driver model is + active. Examples include when using CONFIG_TRACE to trace U-Boot's + execution before driver model is set up. Enable this option to + use an early timer. These functions must be supported by your timer + driver: timer_early_get_count() and timer_early_get_rate(). + config ALTERA_TIMER bool "Altera timer support" depends on TIMER diff --git a/include/timer.h b/include/timer.h index f14725c..dcc803c 100644 --- a/include/timer.h +++ b/include/timer.h @@ -67,4 +67,25 @@ struct timer_dev_priv { unsigned long clock_rate; }; +/** + * timer_early_get_count() - Implement timer_get_count() before driver model + * + * If CONFIG_TIMER_EARLY is enabled, this function wil be called to return + * the current timer value before the proper driver model timer is ready. + * It should be implemented by one of the timer values. This is mostly useful + * for tracing. + */ +u64 timer_early_get_count(void); + +/** + * timer_early_get_rate() - Get the timer rate before driver model + * + * If CONFIG_TIMER_EARLY is enabled, this function wil be called to return + * the current timer rate in Hz before the proper driver model timer is ready. + * It should be implemented by one of the timer values. This is mostly useful + * for tracing. This corresponds to the clock_rate value in struct + * timer_dev_priv. + */ +unsigned long timer_early_get_rate(void); + #endif /* _TIMER_H_ */ @@ -43,11 +43,17 @@ extern unsigned long __weak timer_read_counter(void); #ifdef CONFIG_TIMER ulong notrace get_tbclk(void) { - int ret; + if (!gd->timer) { +#ifdef CONFIG_TIMER_EARLY + return timer_early_get_rate(); +#else + int ret; - ret = dm_timer_init(); - if (ret) - return ret; + ret = dm_timer_init(); + if (ret) + return ret; +#endif + } return timer_get_rate(gd->timer); } @@ -57,9 +63,17 @@ uint64_t notrace get_ticks(void) u64 count; int ret; - ret = dm_timer_init(); - if (ret) - return ret; + if (!gd->timer) { +#ifdef CONFIG_TIMER_EARLY + return timer_early_get_count(); +#else + int ret; + + ret = dm_timer_init(); + if (ret) + return ret; +#endif + } ret = timer_get_count(gd->timer, &count); if (ret) |