From: Guennadi Liakhovetski [EMAIL PROTECTED]
Switch to the standard CFG_HZ=1000 value, while at it, minor white-space
cleanup, remove CFG_CLKS_IN_HZ from config-headers. Tested on mx31ads,
provides 2% or 0.4% precision depending on the
CONFIG_MX31_TIMER_HIGH_PRECISION flag. Measured with stop-watch on 100s
boot-delay.
Signed-off-by: Guennadi Liakhovetski [EMAIL PROTECTED]
---
cpu/arm1136/mx31/interrupts.c | 81 --
include/configs/imx31_litekit.h |4 +-
include/configs/imx31_phycore.h |2 +-
include/configs/mx31ads.h |4 +-
4 files changed, 54 insertions(+), 37 deletions(-)
diff --git a/cpu/arm1136/mx31/interrupts.c b/cpu/arm1136/mx31/interrupts.c
index 6e08c71..4515147 100644
--- a/cpu/arm1136/mx31/interrupts.c
+++ b/cpu/arm1136/mx31/interrupts.c
@@ -27,30 +27,49 @@
#define TIMER_BASE 0x53f9 /* General purpose timer 1 */
/* General purpose timers registers */
-#define GPTCR __REG(TIMER_BASE) /* Control register */
-#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
-#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
-#define GPTCNT __REG(TIMER_BASE + 0x24) /* Counter register */
+#define GPTCR __REG(TIMER_BASE) /* Control register */
+#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
+#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
+#define GPTCNT __REG(TIMER_BASE + 0x24)/* Counter register */
/* General purpose timers bitfields */
-#define GPTCR_SWR (115) /* Software reset */
-#define GPTCR_FRR (19) /* Freerun / restart */
-#define GPTCR_CLKSOURCE_32 (46) /* Clock source */
-#define GPTCR_TEN (1) /* Timer enable */
+#define GPTCR_SWR (1 15) /* Software reset */
+#define GPTCR_FRR (1 9)/* Freerun / restart*/
+#define GPTCR_CLKSOURCE_32 (4 6)/* Clock source */
+#define GPTCR_TEN (1) /* Timer enable */
+
+/* time is measured in 1 / CFG_HZ seconds, tick is internal timer period */
+#ifdef CONFIG_MX31_TIMER_HIGH_PRECISION
+/* ~0.4% error - measured with stop-watch on 100s boot-delay */
+#define TICK_TO_TIME(t)((t) * CFG_HZ / CONFIG_MX31_CLK32)
+#define TIME_TO_TICK(t)((unsigned long long)(t) * CONFIG_MX31_CLK32 /
CFG_HZ)
+#define US_TO_TICK(t) (((unsigned long long)(t) * CONFIG_MX31_CLK32 + \
+ 99) / 100)
+#else
+/* ~2% error */
+#define TICK_PER_TIME ((CONFIG_MX31_CLK32 + CFG_HZ / 2) / CFG_HZ)
+#define US_PER_TICK(100 / CONFIG_MX31_CLK32)
+#define TICK_TO_TIME(t)((t) / TICK_PER_TIME)
+#define TIME_TO_TICK(t)((unsigned long long)(t) * TICK_PER_TIME)
+#define US_TO_TICK(t) (((t) + US_PER_TICK - 1) / US_PER_TICK)
+#endif
static ulong timestamp;
static ulong lastinc;
/* nothing really to do with interrupts, just starts up a counter. */
+/* The 32768Hz 32-bit timer overruns in 131072 seconds */
int interrupt_init (void)
{
int i;
/* setup GP Timer 1 */
GPTCR = GPTCR_SWR;
- for ( i=0; i100; i++) GPTCR = 0; /* We have no udelay by now */
+ for (i = 0; i 100; i++)
+ GPTCR = 0; /* We have no udelay by now */
GPTPR = 0; /* 32Khz */
- GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN; /* Freerun Mode, PERCLK1 input
*/
+ /* Freerun Mode, PERCLK1 input */
+ GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
return 0;
}
@@ -67,9 +86,9 @@ void reset_timer(void)
reset_timer_masked();
}
-ulong get_timer_masked (void)
+unsigned long long get_ticks (void)
{
- ulong now = GPTCNT; /* current tick value */
+ ulong now = GPTCNT;
if (now = lastinc) /* normal mode (non roll) */
/* move stamp forward with absolut diff ticks */
@@ -80,6 +99,17 @@ ulong get_timer_masked (void)
return timestamp;
}
+ulong get_timer_masked (void)
+{
+ /*
+* get_ticks() returns a long long (64 bit), it wraps in
+* 2^64 / CONFIG_MX31_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
+* 5 * 10^9 days... and get_ticks() * CFG_HZ wraps in
+* 5 * 10^6 days - long enough.
+*/
+ return TICK_TO_TIME(get_ticks());
+}
+
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
@@ -87,29 +117,20 @@ ulong get_timer (ulong base)
void set_timer (ulong t)
{
+ timestamp = TIME_TO_TICK(t);
}
/* delay x useconds AND perserve advance timstamp value */
void udelay (unsigned long usec)
{
- ulong tmo, tmp;
-
- if (usec = 1000) { /* if big number, spread
normalization to seconds */
- tmo = usec / 1000; /* start to normalize for usec
to ticks per sec */
- tmo *= CFG_HZ; /* find number of ticks to
wait to achieve target */
- tmo /= 1000;/* finish normalize.
