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reset: make shared pulsed reset controls re-triggerable
The current reset framework API does not allow to release what is done by reset_control_reset(), IOW decrement triggered_count. Add the new reset_control_rearm() call to do so. When reset_control_reset() has been called once, the counter triggered_count, in the reset framework, is incremented i.e the resource under the reset is in-use and the reset should not be done again. reset_control_rearm() would be the way to state that the resource is no longer used and, that from the caller's perspective, the reset can be fired again if necessary. Signed-off-by: Amjad Ouled-Ameur <aouledameur@baylibre.com> Reported-by: Jerome Brunet <jbrunet@baylibre.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
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parent
3650b228f8
commit
557acb3d2c
2 changed files with 74 additions and 0 deletions
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@ -208,6 +208,39 @@ static int reset_control_array_reset(struct reset_control_array *resets)
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return 0;
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}
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static int reset_control_array_rearm(struct reset_control_array *resets)
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{
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struct reset_control *rstc;
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int i;
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for (i = 0; i < resets->num_rstcs; i++) {
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rstc = resets->rstc[i];
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if (!rstc)
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continue;
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if (WARN_ON(IS_ERR(rstc)))
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return -EINVAL;
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if (rstc->shared) {
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if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
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return -EINVAL;
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} else {
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if (!rstc->acquired)
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return -EPERM;
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}
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}
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for (i = 0; i < resets->num_rstcs; i++) {
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rstc = resets->rstc[i];
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if (rstc && rstc->shared)
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WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
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}
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return 0;
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}
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static int reset_control_array_assert(struct reset_control_array *resets)
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{
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int ret, i;
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@ -325,6 +358,46 @@ int reset_control_reset(struct reset_control *rstc)
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}
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EXPORT_SYMBOL_GPL(reset_control_reset);
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/**
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* reset_control_rearm - allow shared reset line to be re-triggered"
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* @rstc: reset controller
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*
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* On a shared reset line the actual reset pulse is only triggered once for the
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* lifetime of the reset_control instance, except if this call is used.
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*
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* Calls to this function must be balanced with calls to reset_control_reset,
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* a warning is thrown in case triggered_count ever dips below 0.
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*
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* Consumers must not use reset_control_(de)assert on shared reset lines when
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* reset_control_reset or reset_control_rearm have been used.
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*
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* If rstc is NULL the function will just return 0.
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*/
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int reset_control_rearm(struct reset_control *rstc)
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{
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if (!rstc)
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return 0;
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if (WARN_ON(IS_ERR(rstc)))
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return -EINVAL;
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if (reset_control_is_array(rstc))
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return reset_control_array_rearm(rstc_to_array(rstc));
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if (rstc->shared) {
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if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
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return -EINVAL;
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WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
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} else {
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if (!rstc->acquired)
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return -EPERM;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(reset_control_rearm);
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/**
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* reset_control_assert - asserts the reset line
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* @rstc: reset controller
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@ -13,6 +13,7 @@ struct reset_control;
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#ifdef CONFIG_RESET_CONTROLLER
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int reset_control_reset(struct reset_control *rstc);
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int reset_control_rearm(struct reset_control *rstc);
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int reset_control_assert(struct reset_control *rstc);
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int reset_control_deassert(struct reset_control *rstc);
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int reset_control_status(struct reset_control *rstc);
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