From: Alessandro Rubini <rub...@unipv.it>
Previously the code wrote 0 to reset the counter and used
negation to read an increasing value from the register. However,
a readback before 400us still returned 0, which was reported
as 1780 seconds, thus nand failed to work any now and then.
As suggested by Wolfgang Denk, this changes READ_TIMER to
just return the hardware counter (a declerasing one) and changes
code using the value. Compile-tested only, at this point.
Signed-off-by: Alessandro Rubini <rub...@unipv.it>
Acked-by: Andrea Gallo <andrea.ga...@stericsson.com>
---
Please note that V3 is being posted at the same time. I prefer
V3 to this V2, but V2 is how I've been asked to do things.
cpu/arm926ejs/nomadik/timer.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/cpu/arm926ejs/nomadik/timer.c b/cpu/arm926ejs/nomadik/timer.c
index 16067c9..c7dd65d 100644
--- a/cpu/arm926ejs/nomadik/timer.c
+++ b/cpu/arm926ejs/nomadik/timer.c
@@ -34,8 +34,8 @@
#define TICKS_PER_HZ (TIMER_CLOCK / CONFIG_SYS_HZ)
#define TICKS_TO_HZ(x) ((x) / TICKS_PER_HZ)
-/* macro to read the 32 bit timer: since it decrements, we invert read value */
-#define READ_TIMER() (~readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0)))
+/* macro to read the 32 bit timer: note however that the count decreases */
+#define READ_TIMER() readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0))
/* Configure a free-running, auto-wrap counter with no prescaler */
int timer_init(void)
@@ -46,7 +46,7 @@ int timer_init(void)
return 0;
}
-/* Restart counting from 0 */
+/* Restart counting from 0 (still, it is a decrementing counter) */
void reset_timer(void)
{
writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0)); /* Immediate effect */
@@ -55,7 +55,7 @@ void reset_timer(void)
/* Return how many HZ passed since "base" */
ulong get_timer(ulong base)
{
- return TICKS_TO_HZ(READ_TIMER()) - base;
+ return TICKS_TO_HZ(-READ_TIMER()) - base;
}
/* Delay x useconds */
@@ -63,8 +63,8 @@ void udelay(unsigned long usec)
{
ulong ini, end;
- ini = READ_TIMER();
- end = ini + USEC_TO_COUNT(usec);
- while ((signed)(end - READ_TIMER()) > 0)
+ ini = READ_TIMER(); /* decrementing value */
+ end = ini - USEC_TO_COUNT(usec);
+ while ((signed)(READ_TIMER() - end) > 0)
;
}
--
1.6.0.2
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