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i.MX: Allow GPT timer to rollover.

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GPT timer need to rollover when it reaches 0xffffffff.

It also need to reset to 0 when in "restart mode" and crossing the
compare 1 register.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jean-Christophe Dubois <jcd@tribudubois.net>
Message-id: 6e2b36117a249a78bf822dd59a390368f407136e.1456868959.git.jcd@tribudubois.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Jean-Christophe Dubois 2016-03-16 17:05:59 +00:00 committed by Peter Maydell
parent 9c94d8e6c9
commit 4833e15f74
1 changed files with 15 additions and 12 deletions
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27
hw/timer/imx_gpt.c
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@ -134,7 +134,7 @@ static inline uint32_t imx_gpt_find_limit(uint32_t count, uint32_t reg,
static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event) static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event)
{ {
uint32_t timeout = GPT_TIMER_MAX; uint32_t timeout = GPT_TIMER_MAX;
uint32_t count = 0; uint32_t count;
long long limit; long long limit;
if (!(s->cr & GPT_CR_EN)) { if (!(s->cr & GPT_CR_EN)) {
@ -142,20 +142,23 @@ static void imx_gpt_compute_next_timeout(IMXGPTState *s, bool event)
return; return;
} }
/* update the count */
count = imx_gpt_update_count(s);
if (event) { if (event) {
/* This is a timer event */ /*
* This is an event (the ptimer reached 0 and stopped), and the
if ((s->cr & GPT_CR_FRR) && (s->next_timeout != GPT_TIMER_MAX)) { * timer counter is now equal to s->next_timeout.
/* */
* if we are in free running mode and we have not reached if (!(s->cr & GPT_CR_FRR) && (count == s->ocr1)) {
* the GPT_TIMER_MAX limit, then update the count /* We are in restart mode and we crossed the compare channel 1
* value. We need to reset the counter to 0.
*/ */
count = imx_gpt_update_count(s); count = s->cnt = s->next_timeout = 0;
} else if (count == GPT_TIMER_MAX) {
/* We reached GPT_TIMER_MAX so we need to rollover */
count = s->cnt = s->next_timeout = 0;
} }
} else {
/* not a timer event, then just update the count */
count = imx_gpt_update_count(s);
} }
/* now, find the next timeout related to count */ /* now, find the next timeout related to count */