[U-Boot] [PATCH v2 2/9] Introduce common timer functions

Rob Herring
2013-10-04T15:22:41Z

Many platforms duplicate pretty much the same timer code yet they all have
a 32-bit freerunning counter register. Create a common implementation that
minimally requires 2 or 3 defines to add timer support:

CONFIG_SYS_TIMER_RATE - Clock rate of the timer counter
CONFIG_SYS_TIMER_COUNTER - Address of 32-bit counter
CONFIG_SYS_TIMER_COUNTS_DOWN - Define if counter counts down

All functions are weak or ifdef'ed so they can still be overriden by any
platform.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
v2:
- Move to common location for all arches
- Add extern timer_read_counter declaration
- Add new global data timebase_h and timebase_l

include/asm-generic/global_data.h | 2 ++
lib/time.c | 73 +++++++++++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+)

diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 77e06fb..0de0bea 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -72,6 +72,8 @@ typedef struct global_data {
#if defined(CONFIG_SYS_I2C)
int cur_i2c_bus; /* current used i2c bus */
#endif
+ unsigned long timebase_h;
+ unsigned long timebase_l;
struct arch_global_data arch; /* architecture-specific data */
} gd_t;
#endif
diff --git a/lib/time.c b/lib/time.c
index 68b8ff4..761272a 100644
--- a/lib/time.c
+++ b/lib/time.c
@@ -7,11 +7,84 @@

#include <common.h>
#include <watchdog.h>
+#include <div64.h>
+#include <asm/io.h>

#ifndef CONFIG_WD_PERIOD
# define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default*/
#endif

+DECLARE_GLOBAL_DATA_PTR;
+
+#ifdef CONFIG_SYS_TIMER_RATE
+ulong notrace get_tbclk(void)
+{
+ return CONFIG_SYS_TIMER_RATE;
+}
+#endif
+
+#ifdef CONFIG_SYS_TIMER_COUNTER
+unsigned long notrace timer_read_counter(void)
+{
+#ifdef CONFIG_SYS_TIMER_COUNTS_DOWN
+ return ~readl(CONFIG_SYS_TIMER_COUNTER);
+#else
+ return readl(CONFIG_SYS_TIMER_COUNTER);
+#endif
+}
+#else
+extern unsigned long timer_read_counter(void);
+#endif
+
+unsigned long long __weak notrace get_ticks(void)
+{
+ unsigned long now = timer_read_counter();
+
+ /* increment tbu if tbl has rolled over */
+ if (now < gd->timebase_l)
+ gd->timebase_h++;
+ gd->timebase_l = now;
+ return ((unsigned long long)gd->timebase_h << 32) | gd->timebase_l;
+}
+
+static unsigned long long notrace tick_to_time(unsigned long long tick)
+{
+ unsigned int div = get_tbclk();
+
+ tick *= CONFIG_SYS_HZ;
+ do_div(tick, div);
+ return tick;
+}
+
+ulong __weak get_timer(ulong base)
+{
+ return tick_to_time(get_ticks()) - base;
+}
+
+unsigned long __weak notrace timer_get_us(void)
+{
+ return tick_to_time(get_ticks() * 1000);
+}
+static unsigned long long usec_to_tick(unsigned long usec)
+{
+ unsigned long long tick = usec * get_tbclk();
+ usec *= get_tbclk();
+ do_div(tick, 1000000);
+ return tick;
+}
+
+void __weak __udelay(unsigned long usec)
+{
+ unsigned long long tmp;
+ ulong tmo;
+
+ tmo = usec_to_tick(usec);
+ tmp = get_ticks() + tmo; /* get current timestamp */
+
+ while (get_ticks() < tmp) /* loop till event */
+ /*NOP*/;
+}
+
/* ------------------------------------------------------------------------- */

void udelay(unsigned long usec)
--
1.8.1.2