staticvoid clk_pm_runtime_put(struct clk_core *core)
{ if (!core->rpm_enabled) return;
pm_runtime_put_sync(core->dev);
}
/** * clk_pm_runtime_get_all() - Runtime "get" all clk provider devices * * Call clk_pm_runtime_get() on all runtime PM enabled clks in the clk tree so * that disabling unused clks avoids a deadlock where a device is runtime PM * resuming/suspending and the runtime PM callback is trying to grab the * prepare_lock for something like clk_prepare_enable() while * clk_disable_unused_subtree() holds the prepare_lock and is trying to runtime * PM resume/suspend the device as well. * * Context: Acquires the 'clk_rpm_list_lock' and returns with the lock held on * success. Otherwise the lock is released on failure. * * Return: 0 on success, negative errno otherwise.
*/ staticint clk_pm_runtime_get_all(void)
{ int ret; struct clk_core *core, *failed;
/* * Grab the list lock to prevent any new clks from being registered * or unregistered until clk_pm_runtime_put_all().
*/
mutex_lock(&clk_rpm_list_lock);
/* * Runtime PM "get" all the devices that are needed for the clks * currently registered. Do this without holding the prepare_lock, to * avoid the deadlock.
*/
hlist_for_each_entry(core, &clk_rpm_list, rpm_node) {
ret = clk_pm_runtime_get(core); if (ret) {
failed = core;
pr_err("clk: Failed to runtime PM get '%s' for clk '%s'\n",
dev_name(failed->dev), failed->name); goto err;
}
}
return 0;
err:
hlist_for_each_entry(core, &clk_rpm_list, rpm_node) { if (core == failed) break;
/** * clk_pm_runtime_put_all() - Runtime "put" all clk provider devices * * Put the runtime PM references taken in clk_pm_runtime_get_all() and release * the 'clk_rpm_list_lock'.
*/ staticvoid clk_pm_runtime_put_all(void)
{ struct clk_core *core;
/* * On UP systems, spin_trylock_irqsave() always returns true, even if * we already hold the lock. So, in that case, we rely only on * reference counting.
*/ if (!IS_ENABLED(CONFIG_SMP) ||
!spin_trylock_irqsave(&enable_lock, flags)) { if (enable_owner == current) {
enable_refcnt++;
__acquire(enable_lock); if (!IS_ENABLED(CONFIG_SMP))
local_save_flags(flags); return flags;
}
spin_lock_irqsave(&enable_lock, flags);
}
WARN_ON_ONCE(enable_owner != NULL);
WARN_ON_ONCE(enable_refcnt != 0);
enable_owner = current;
enable_refcnt = 1; return flags;
}
staticbool clk_core_is_prepared(struct clk_core *core)
{ bool ret = false;
/* * .is_prepared is optional for clocks that can prepare * fall back to software usage counter if it is missing
*/ if (!core->ops->is_prepared) return core->prepare_count;
if (!clk_pm_runtime_get(core)) {
ret = core->ops->is_prepared(core->hw);
clk_pm_runtime_put(core);
}
return ret;
}
staticbool clk_core_is_enabled(struct clk_core *core)
{ bool ret = false;
/* * .is_enabled is only mandatory for clocks that gate * fall back to software usage counter if .is_enabled is missing
*/ if (!core->ops->is_enabled) return core->enable_count;
/* * Check if clock controller's device is runtime active before * calling .is_enabled callback. If not, assume that clock is * disabled, because we might be called from atomic context, from * which pm_runtime_get() is not allowed. * This function is called mainly from clk_disable_unused_subtree, * which ensures proper runtime pm activation of controller before * taking enable spinlock, but the below check is needed if one tries * to call it from other places.
*/ if (core->rpm_enabled) {
pm_runtime_get_noresume(core->dev); if (!pm_runtime_active(core->dev)) {
ret = false; goto done;
}
}
/* * This could be called with the enable lock held, or from atomic * context. If the parent isn't enabled already, we can't do * anything here. We can also assume this clock isn't enabled.
*/ if ((core->flags & CLK_OPS_PARENT_ENABLE) && core->parent) if (!clk_core_is_enabled(core->parent)) {
ret = false; goto done;
}
ret = core->ops->is_enabled(core->hw);
done: if (core->rpm_enabled)
pm_runtime_put(core->dev);
/* search the 'proper' clk tree first */
hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
ret = __clk_lookup_subtree(name, root_clk); if (ret) return ret;
}
/* if not found, then search the orphan tree */
hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
ret = __clk_lookup_subtree(name, root_clk); if (ret) return ret;
}
/** * clk_core_get - Find the clk_core parent of a clk * @core: clk to find parent of * @p_index: parent index to search for * * This is the preferred method for clk providers to find the parent of a * clk when that parent is external to the clk controller. The parent_names * array is indexed and treated as a local name matching a string in the device * node's 'clock-names' property or as the 'con_id' matching the device's * dev_name() in a clk_lookup. This allows clk providers to use their own * namespace instead of looking for a globally unique parent string. * * For example the following DT snippet would allow a clock registered by the * clock-controller@c001 that has a clk_init_data::parent_data array * with 'xtal' in the 'name' member to find the clock provided by the * clock-controller@f00abcd without needing to get the globally unique name of * the xtal clk. * * parent: clock-controller@f00abcd { * reg = <0xf00abcd 0xabcd>; * #clock-cells = <0>; * }; * * clock-controller@c001 { * reg = <0xc001 0xf00d>; * clocks = <&parent>; * clock-names = "xtal"; * #clock-cells = <1>; * }; * * Returns: -ENOENT when the provider can't be found or the clk doesn't * exist in the provider or the name can't be found in the DT node or * in a clkdev lookup. NULL when the provider knows about the clk but it * isn't provided on this system. * A valid clk_core pointer when the clk can be found in the provider.
*/ staticstruct clk_core *clk_core_get(struct clk_core *core, u8 p_index)
{ constchar *name = core->parents[p_index].fw_name; int index = core->parents[p_index].index; struct clk_hw *hw = ERR_PTR(-ENOENT); struct device *dev = core->dev; constchar *dev_id = dev ? dev_name(dev) : NULL; struct device_node *np = core->of_node; struct of_phandle_args clkspec;
if (np && (name || index >= 0) &&
!of_parse_clkspec(np, index, name, &clkspec)) {
hw = of_clk_get_hw_from_clkspec(&clkspec);
of_node_put(clkspec.np);
} elseif (name) { /* * If the DT search above couldn't find the provider fallback to * looking up via clkdev based clk_lookups.
*/
hw = clk_find_hw(dev_id, name);
}
/* * We have a direct reference but it isn't registered yet? * Orphan it and let clk_reparent() update the orphan status * when the parent is registered.
*/ if (!parent)
parent = ERR_PTR(-EPROBE_DEFER);
/* Only cache it if it's not an error */ if (!IS_ERR(parent))
entry->core = parent;
}
staticstruct clk_core *clk_core_get_parent_by_index(struct clk_core *core,
u8 index)
{ if (!core || index >= core->num_parents || !core->parents) return NULL;
if (!core->parents[index].core)
clk_core_fill_parent_index(core, index);
staticunsignedlong clk_core_get_rate_nolock(struct clk_core *core)
{ if (!core) return 0;
if (!core->num_parents || core->parent) return core->rate;
/* * Clk must have a parent because num_parents > 0 but the parent isn't * known yet. Best to return 0 as the rate of this clk until we can * properly recalc the rate based on the parent's rate.
*/ return 0;
}
ret = clk_core_round_rate_nolock(parent, &parent_req); if (ret) return ret;
trace_clk_rate_request_done(&parent_req);
best = parent_req.rate;
} elseif (parent) {
best = clk_core_get_rate_nolock(parent);
} else {
best = clk_core_get_rate_nolock(core);
}
req->best_parent_rate = best;
req->rate = best;
return 0;
}
int clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request *req, unsignedlong flags)
{ struct clk_core *core = hw->core, *parent, *best_parent = NULL; int i, num_parents, ret; unsignedlong best = 0;
/* if NO_REPARENT flag set, pass through to current parent */ if (core->flags & CLK_SET_RATE_NO_REPARENT) return clk_core_determine_rate_no_reparent(hw, req);
/* find the parent that can provide the fastest rate <= rate */
num_parents = core->num_parents; for (i = 0; i < num_parents; i++) { unsignedlong parent_rate;
parent = clk_core_get_parent_by_index(core, i); if (!parent) continue;
if (core->flags & CLK_SET_RATE_PARENT) { struct clk_rate_request parent_req;
/* * clk_hw_get_rate_range() - returns the clock rate range for a hw clk * @hw: the hw clk we want to get the range from * @min_rate: pointer to the variable that will hold the minimum * @max_rate: pointer to the variable that will hold the maximum * * Fills the @min_rate and @max_rate variables with the minimum and * maximum that clock can reach.
*/ void clk_hw_get_rate_range(struct clk_hw *hw, unsignedlong *min_rate, unsignedlong *max_rate)
{
clk_core_get_boundaries(hw->core, min_rate, max_rate);
}
EXPORT_SYMBOL_GPL(clk_hw_get_rate_range);
/* * __clk_mux_determine_rate - clk_ops::determine_rate implementation for a mux type clk * @hw: mux type clk to determine rate on * @req: rate request, also used to return preferred parent and frequencies * * Helper for finding best parent to provide a given frequency. This can be used * directly as a determine_rate callback (e.g. for a mux), or from a more * complex clock that may combine a mux with other operations. * * Returns: 0 on success, -EERROR value on error
*/ int __clk_mux_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
{ return clk_mux_determine_rate_flags(hw, req, 0);
}
EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
/* * clk_hw_determine_rate_no_reparent - clk_ops::determine_rate implementation for a clk that doesn't reparent * @hw: mux type clk to determine rate on * @req: rate request, also used to return preferred frequency * * Helper for finding best parent rate to provide a given frequency. * This can be used directly as a determine_rate callback (e.g. for a * mux), or from a more complex clock that may combine a mux with other * operations. * * Returns: 0 on success, -EERROR value on error
*/ int clk_hw_determine_rate_no_reparent(struct clk_hw *hw, struct clk_rate_request *req)
{ return clk_core_determine_rate_no_reparent(hw, req);
}
EXPORT_SYMBOL_GPL(clk_hw_determine_rate_no_reparent);
if (WARN(core->protect_count == 0, "%s already unprotected\n", core->name)) return;
if (--core->protect_count > 0) return;
clk_core_rate_unprotect(core->parent);
}
staticint clk_core_rate_nuke_protect(struct clk_core *core)
{ int ret;
lockdep_assert_held(&prepare_lock);
if (!core) return -EINVAL;
if (core->protect_count == 0) return 0;
ret = core->protect_count;
core->protect_count = 1;
clk_core_rate_unprotect(core);
return ret;
}
/** * clk_rate_exclusive_put - release exclusivity over clock rate control * @clk: the clk over which the exclusivity is released * * clk_rate_exclusive_put() completes a critical section during which a clock * consumer cannot tolerate any other consumer making any operation on the * clock which could result in a rate change or rate glitch. Exclusive clocks * cannot have their rate changed, either directly or indirectly due to changes * further up the parent chain of clocks. As a result, clocks up parent chain * also get under exclusive control of the calling consumer. * * If exlusivity is claimed more than once on clock, even by the same consumer, * the rate effectively gets locked as exclusivity can't be preempted. * * Calls to clk_rate_exclusive_put() must be balanced with calls to * clk_rate_exclusive_get(). Calls to this function may sleep, and do not return * error status.
*/ void clk_rate_exclusive_put(struct clk *clk)
{ if (!clk) return;
clk_prepare_lock();
/* * if there is something wrong with this consumer protect count, stop * here before messing with the provider
*/ if (WARN_ON(clk->exclusive_count <= 0)) goto out;
/** * clk_rate_exclusive_get - get exclusivity over the clk rate control * @clk: the clk over which the exclusity of rate control is requested * * clk_rate_exclusive_get() begins a critical section during which a clock * consumer cannot tolerate any other consumer making any operation on the * clock which could result in a rate change or rate glitch. Exclusive clocks * cannot have their rate changed, either directly or indirectly due to changes * further up the parent chain of clocks. As a result, clocks up parent chain * also get under exclusive control of the calling consumer. * * If exlusivity is claimed more than once on clock, even by the same consumer, * the rate effectively gets locked as exclusivity can't be preempted. * * Calls to clk_rate_exclusive_get() should be balanced with calls to * clk_rate_exclusive_put(). Calls to this function may sleep. * Returns 0 on success, -EERROR otherwise
*/ int clk_rate_exclusive_get(struct clk *clk)
{ if (!clk) return 0;
/** * clk_unprepare - undo preparation of a clock source * @clk: the clk being unprepared * * clk_unprepare may sleep, which differentiates it from clk_disable. In a * simple case, clk_unprepare can be used instead of clk_disable to gate a clk * if the operation may sleep. One example is a clk which is accessed over * I2c. In the complex case a clk gate operation may require a fast and a slow * part. It is this reason that clk_unprepare and clk_disable are not mutually * exclusive. In fact clk_disable must be called before clk_unprepare.
*/ void clk_unprepare(struct clk *clk)
{ if (IS_ERR_OR_NULL(clk)) return;
staticint clk_core_prepare(struct clk_core *core)
{ int ret = 0;
lockdep_assert_held(&prepare_lock);
if (!core) return 0;
if (core->prepare_count == 0) {
ret = clk_pm_runtime_get(core); if (ret) return ret;
ret = clk_core_prepare(core->parent); if (ret) goto runtime_put;
trace_clk_prepare(core);
if (core->ops->prepare)
ret = core->ops->prepare(core->hw);
trace_clk_prepare_complete(core);
if (ret) goto unprepare;
}
core->prepare_count++;
/* * CLK_SET_RATE_GATE is a special case of clock protection * Instead of a consumer claiming exclusive rate control, it is * actually the provider which prevents any consumer from making any * operation which could result in a rate change or rate glitch while * the clock is prepared.
*/ if (core->flags & CLK_SET_RATE_GATE)
clk_core_rate_protect(core);
staticint clk_core_prepare_lock(struct clk_core *core)
{ int ret;
clk_prepare_lock();
ret = clk_core_prepare(core);
clk_prepare_unlock();
return ret;
}
/** * clk_prepare - prepare a clock source * @clk: the clk being prepared * * clk_prepare may sleep, which differentiates it from clk_enable. In a simple * case, clk_prepare can be used instead of clk_enable to ungate a clk if the * operation may sleep. One example is a clk which is accessed over I2c. In * the complex case a clk ungate operation may require a fast and a slow part. * It is this reason that clk_prepare and clk_enable are not mutually * exclusive. In fact clk_prepare must be called before clk_enable. * Returns 0 on success, -EERROR otherwise.
*/ int clk_prepare(struct clk *clk)
{ if (!clk) return 0;
/** * clk_disable - gate a clock * @clk: the clk being gated * * clk_disable must not sleep, which differentiates it from clk_unprepare. In * a simple case, clk_disable can be used instead of clk_unprepare to gate a * clk if the operation is fast and will never sleep. One example is a * SoC-internal clk which is controlled via simple register writes. In the * complex case a clk gate operation may require a fast and a slow part. It is * this reason that clk_unprepare and clk_disable are not mutually exclusive. * In fact clk_disable must be called before clk_unprepare.
*/ void clk_disable(struct clk *clk)
{ if (IS_ERR_OR_NULL(clk)) return;
staticint clk_core_enable(struct clk_core *core)
{ int ret = 0;
lockdep_assert_held(&enable_lock);
if (!core) return 0;
if (WARN(core->prepare_count == 0, "Enabling unprepared %s\n", core->name)) return -ESHUTDOWN;
if (core->enable_count == 0) {
ret = clk_core_enable(core->parent);
if (ret) return ret;
trace_clk_enable(core);
if (core->ops->enable)
ret = core->ops->enable(core->hw);
trace_clk_enable_complete(core);
if (ret) {
clk_core_disable(core->parent); return ret;
}
}
core->enable_count++; return 0;
}
staticint clk_core_enable_lock(struct clk_core *core)
{ unsignedlong flags; int ret;
flags = clk_enable_lock();
ret = clk_core_enable(core);
clk_enable_unlock(flags);
return ret;
}
/** * clk_gate_restore_context - restore context for poweroff * @hw: the clk_hw pointer of clock whose state is to be restored * * The clock gate restore context function enables or disables * the gate clocks based on the enable_count. This is done in cases * where the clock context is lost and based on the enable_count * the clock either needs to be enabled/disabled. This * helps restore the state of gate clocks.
*/ void clk_gate_restore_context(struct clk_hw *hw)
{ struct clk_core *core = hw->core;
if (core->enable_count)
core->ops->enable(hw); else
core->ops->disable(hw);
}
EXPORT_SYMBOL_GPL(clk_gate_restore_context);
staticint clk_core_save_context(struct clk_core *core)
{ struct clk_core *child; int ret = 0;
hlist_for_each_entry(child, &core->children, child_node) {
ret = clk_core_save_context(child); if (ret < 0) return ret;
}
if (core->ops && core->ops->save_context)
ret = core->ops->save_context(core->hw);
/** * clk_save_context - save clock context for poweroff * * Saves the context of the clock register for powerstates in which the * contents of the registers will be lost. Occurs deep within the suspend * code. Returns 0 on success.
*/ int clk_save_context(void)
{ struct clk_core *clk; int ret;
hlist_for_each_entry(clk, &clk_root_list, child_node) {
ret = clk_core_save_context(clk); if (ret < 0) return ret;
}
hlist_for_each_entry(clk, &clk_orphan_list, child_node) {
ret = clk_core_save_context(clk); if (ret < 0) return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(clk_save_context);
/** * clk_restore_context - restore clock context after poweroff * * Restore the saved clock context upon resume. *
*/ void clk_restore_context(void)
{ struct clk_core *core;
/** * clk_enable - ungate a clock * @clk: the clk being ungated * * clk_enable must not sleep, which differentiates it from clk_prepare. In a * simple case, clk_enable can be used instead of clk_prepare to ungate a clk * if the operation will never sleep. One example is a SoC-internal clk which * is controlled via simple register writes. In the complex case a clk ungate * operation may require a fast and a slow part. It is this reason that * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare * must be called before clk_enable. Returns 0 on success, -EERROR * otherwise.
*/ int clk_enable(struct clk *clk)
{ if (!clk) return 0;
/** * clk_is_enabled_when_prepared - indicate if preparing a clock also enables it. * @clk: clock source * * Returns true if clk_prepare() implicitly enables the clock, effectively * making clk_enable()/clk_disable() no-ops, false otherwise. * * This is of interest mainly to power management code where actually * disabling the clock also requires unpreparing it to have any material * effect. * * Regardless of the value returned here, the caller must always invoke * clk_enable() or clk_prepare_enable() and counterparts for usage counts * to be right.
*/ bool clk_is_enabled_when_prepared(struct clk *clk)
{ return clk && !(clk->core->ops->enable && clk->core->ops->disable);
}
EXPORT_SYMBOL_GPL(clk_is_enabled_when_prepared);
staticint clk_core_prepare_enable(struct clk_core *core)
{ int ret;
ret = clk_core_prepare_lock(core); if (ret) return ret;
ret = clk_core_enable_lock(core); if (ret)
clk_core_unprepare_lock(core);
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_prepare_enable(core->parent);
flags = clk_enable_lock();
if (core->enable_count) goto unlock_out;
if (core->flags & CLK_IGNORE_UNUSED) goto unlock_out;
/* * some gate clocks have special needs during the disable-unused * sequence. call .disable_unused if available, otherwise fall * back to .disable
*/ if (clk_core_is_enabled(core)) {
trace_clk_disable(core); if (core->ops->disable_unused)
core->ops->disable_unused(core->hw); elseif (core->ops->disable)
core->ops->disable(core->hw);
trace_clk_disable_complete(core);
}
unlock_out:
clk_enable_unlock(flags); if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(core->parent);
}
staticint __init clk_disable_unused(void)
{ struct clk_core *core; int ret;
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n"); return 0;
}
pr_info("clk: Disabling unused clocks\n");
ret = clk_pm_runtime_get_all(); if (ret) return ret; /* * Grab the prepare lock to keep the clk topology stable while iterating * over clks.
*/
clk_prepare_lock();
staticint clk_core_determine_round_nolock(struct clk_core *core, struct clk_rate_request *req)
{ long rate;
lockdep_assert_held(&prepare_lock);
if (!core) return 0;
/* * Some clock providers hand-craft their clk_rate_requests and * might not fill min_rate and max_rate. * * If it's the case, clamping the rate is equivalent to setting * the rate to 0 which is bad. Skip the clamping but complain so * that it gets fixed, hopefully.
*/ if (!req->min_rate && !req->max_rate)
pr_warn("%s: %s: clk_rate_request has initialized min or max rate.\n",
__func__, core->name); else
req->rate = clamp(req->rate, req->min_rate, req->max_rate);
/* * At this point, core protection will be disabled * - if the provider is not protected at all * - if the calling consumer is the only one which has exclusivity * over the provider
*/ if (clk_core_rate_is_protected(core)) {
req->rate = core->rate;
} elseif (core->ops->determine_rate) { return core->ops->determine_rate(core->hw, req);
} elseif (core->ops->round_rate) {
rate = core->ops->round_rate(core->hw, req->rate,
&req->best_parent_rate); if (rate < 0) return rate;
/** * clk_hw_init_rate_request - Initializes a clk_rate_request * @hw: the clk for which we want to submit a rate request * @req: the clk_rate_request structure we want to initialise * @rate: the rate which is to be requested * * Initializes a clk_rate_request structure to submit to * __clk_determine_rate() or similar functions.
*/ void clk_hw_init_rate_request(conststruct clk_hw *hw, struct clk_rate_request *req, unsignedlong rate)
{ if (WARN_ON(!hw || !req)) return;
/** * clk_hw_forward_rate_request - Forwards a clk_rate_request to a clock's parent * @hw: the original clock that got the rate request * @old_req: the original clk_rate_request structure we want to forward * @parent: the clk we want to forward @old_req to * @req: the clk_rate_request structure we want to initialise * @parent_rate: The rate which is to be requested to @parent * * Initializes a clk_rate_request structure to submit to a clock parent * in __clk_determine_rate() or similar functions.
*/ void clk_hw_forward_rate_request(conststruct clk_hw *hw, conststruct clk_rate_request *old_req, conststruct clk_hw *parent, struct clk_rate_request *req, unsignedlong parent_rate)
{ if (WARN_ON(!hw || !old_req || !parent || !req)) return;
/** * __clk_determine_rate - get the closest rate actually supported by a clock * @hw: determine the rate of this clock * @req: target rate request * * Useful for clk_ops such as .set_rate and .determine_rate.
*/ int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
{ if (!hw) {
req->rate = 0; return 0;
}
/** * clk_hw_round_rate() - round the given rate for a hw clk * @hw: the hw clk for which we are rounding a rate * @rate: the rate which is to be rounded * * Takes in a rate as input and rounds it to a rate that the clk can actually * use. * * Context: prepare_lock must be held. * For clk providers to call from within clk_ops such as .round_rate, * .determine_rate. * * Return: returns rounded rate of hw clk if clk supports round_rate operation * else returns the parent rate.
*/ unsignedlong clk_hw_round_rate(struct clk_hw *hw, unsignedlong rate)
{ int ret; struct clk_rate_request req;
clk_core_init_rate_req(hw->core, &req, rate);
trace_clk_rate_request_start(&req);
ret = clk_core_round_rate_nolock(hw->core, &req); if (ret) return 0;
/** * clk_round_rate - round the given rate for a clk * @clk: the clk for which we are rounding a rate * @rate: the rate which is to be rounded * * Takes in a rate as input and rounds it to a rate that the clk can actually * use which is then returned. If clk doesn't support round_rate operation * then the parent rate is returned.
*/ long clk_round_rate(struct clk *clk, unsignedlong rate)
{ struct clk_rate_request req; int ret;
if (!clk) return 0;
clk_prepare_lock();
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
clk_core_init_rate_req(clk->core, &req, rate);
trace_clk_rate_request_start(&req);
ret = clk_core_round_rate_nolock(clk->core, &req);
trace_clk_rate_request_done(&req);
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
/** * __clk_notify - call clk notifier chain * @core: clk that is changing rate * @msg: clk notifier type (see include/linux/clk.h) * @old_rate: old clk rate * @new_rate: new clk rate * * Triggers a notifier call chain on the clk rate-change notification * for 'clk'. Passes a pointer to the struct clk and the previous * and current rates to the notifier callback. Intended to be called by * internal clock code only. Returns NOTIFY_DONE from the last driver * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if * a driver returns that.
*/ staticint __clk_notify(struct clk_core *core, unsignedlong msg, unsignedlong old_rate, unsignedlong new_rate)
{ struct clk_notifier *cn; struct clk_notifier_data cnd; int ret = NOTIFY_DONE;
cnd.old_rate = old_rate;
cnd.new_rate = new_rate;
list_for_each_entry(cn, &clk_notifier_list, node) { if (cn->clk->core == core) {
cnd.clk = cn->clk;
ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
&cnd); if (ret & NOTIFY_STOP_MASK) return ret;
}
}
return ret;
}
/** * __clk_recalc_accuracies * @core: first clk in the subtree * * Walks the subtree of clks starting with clk and recalculates accuracies as * it goes. Note that if a clk does not implement the .recalc_accuracy * callback then it is assumed that the clock will take on the accuracy of its * parent.
*/ staticvoid __clk_recalc_accuracies(struct clk_core *core)
{ unsignedlong parent_accuracy = 0; struct clk_core *child;
lockdep_assert_held(&prepare_lock);
if (core->parent)
parent_accuracy = core->parent->accuracy;
if (core->ops->recalc_accuracy)
core->accuracy = core->ops->recalc_accuracy(core->hw,
parent_accuracy); else
core->accuracy = parent_accuracy;
/** * clk_get_accuracy - return the accuracy of clk * @clk: the clk whose accuracy is being returned * * Simply returns the cached accuracy of the clk, unless * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be * issued. * If clk is NULL then returns 0.
*/ long clk_get_accuracy(struct clk *clk)
{ long accuracy;
/** * __clk_recalc_rates * @core: first clk in the subtree * @update_req: Whether req_rate should be updated with the new rate * @msg: notification type (see include/linux/clk.h) * * Walks the subtree of clks starting with clk and recalculates rates as it * goes. Note that if a clk does not implement the .recalc_rate callback then * it is assumed that the clock will take on the rate of its parent. * * clk_recalc_rates also propagates the POST_RATE_CHANGE notification, * if necessary.
*/ staticvoid __clk_recalc_rates(struct clk_core *core, bool update_req, unsignedlong msg)
{ unsignedlong old_rate; unsignedlong parent_rate = 0; struct clk_core *child;
lockdep_assert_held(&prepare_lock);
old_rate = core->rate;
if (core->parent)
parent_rate = core->parent->rate;
core->rate = clk_recalc(core, parent_rate); if (update_req)
core->req_rate = core->rate;
/* * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE * & ABORT_RATE_CHANGE notifiers
*/ if (core->notifier_count && msg)
__clk_notify(core, msg, old_rate, core->rate);
/** * clk_get_rate - return the rate of clk * @clk: the clk whose rate is being returned * * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag * is set, which means a recalc_rate will be issued. Can be called regardless of * the clock enabledness. If clk is NULL, or if an error occurred, then returns * 0.
*/ unsignedlong clk_get_rate(struct clk *clk)
{ unsignedlong rate;
staticint clk_fetch_parent_index(struct clk_core *core, struct clk_core *parent)
{ int i;
if (!parent) return -EINVAL;
for (i = 0; i < core->num_parents; i++) { /* Found it first try! */ if (core->parents[i].core == parent) return i;
/* Something else is here, so keep looking */ if (core->parents[i].core) continue;
/* Maybe core hasn't been cached but the hw is all we know? */ if (core->parents[i].hw) { if (core->parents[i].hw == parent->hw) break;
/* Didn't match, but we're expecting a clk_hw */ continue;
}
/* Maybe it hasn't been cached (clk_set_parent() path) */ if (parent == clk_core_get(core, i)) break;
/* Fallback to comparing globally unique names */ if (core->parents[i].name &&
!strcmp(parent->name, core->parents[i].name)) break;
}
if (i == core->num_parents) return -EINVAL;
core->parents[i].core = parent; return i;
}
/** * clk_hw_get_parent_index - return the index of the parent clock * @hw: clk_hw associated with the clk being consumed * * Fetches and returns the index of parent clock. Returns -EINVAL if the given * clock does not have a current parent.
*/ int clk_hw_get_parent_index(struct clk_hw *hw)
{ struct clk_hw *parent = clk_hw_get_parent(hw);
/* * Update the orphan status of @core and all its children.
*/ staticvoid clk_core_update_orphan_status(struct clk_core *core, bool is_orphan)
{ struct clk_core *child;
/* * 1. enable parents for CLK_OPS_PARENT_ENABLE clock * * 2. Migrate prepare state between parents and prevent race with * clk_enable(). * * If the clock is not prepared, then a race with * clk_enable/disable() is impossible since we already have the * prepare lock (future calls to clk_enable() need to be preceded by * a clk_prepare()). * * If the clock is prepared, migrate the prepared state to the new * parent and also protect against a race with clk_enable() by * forcing the clock and the new parent on. This ensures that all * future calls to clk_enable() are practically NOPs with respect to * hardware and software states. * * See also: Comment for clk_set_parent() below.
*/
/* enable old_parent & parent if CLK_OPS_PARENT_ENABLE is set */ if (core->flags & CLK_OPS_PARENT_ENABLE) {
clk_core_prepare_enable(old_parent);
clk_core_prepare_enable(parent);
}
/* migrate prepare count if > 0 */ if (core->prepare_count) {
clk_core_prepare_enable(parent);
clk_core_enable_lock(core);
}
/* update the clk tree topology */
flags = clk_enable_lock();
clk_reparent(core, parent);
clk_enable_unlock(flags);
return old_parent;
}
staticvoid __clk_set_parent_after(struct clk_core *core, struct clk_core *parent, struct clk_core *old_parent)
{ /* * Finish the migration of prepare state and undo the changes done * for preventing a race with clk_enable().
*/ if (core->prepare_count) {
clk_core_disable_lock(core);
clk_core_disable_unprepare(old_parent);
}
/* re-balance ref counting if CLK_OPS_PARENT_ENABLE is set */ if (core->flags & CLK_OPS_PARENT_ENABLE) {
clk_core_disable_unprepare(parent);
clk_core_disable_unprepare(old_parent);
}
}
staticint __clk_set_parent(struct clk_core *core, struct clk_core *parent,
u8 p_index)
{ unsignedlong flags; int ret = 0; struct clk_core *old_parent;
/* change clock input source */ if (parent && core->ops->set_parent)
ret = core->ops->set_parent(core->hw, p_index);
trace_clk_set_parent_complete(core, parent);
if (ret) {
flags = clk_enable_lock();
clk_reparent(core, old_parent);
clk_enable_unlock(flags);
__clk_set_parent_after(core, old_parent, parent);
return ret;
}
__clk_set_parent_after(core, parent, old_parent);
return 0;
}
/** * __clk_speculate_rates * @core: first clk in the subtree * @parent_rate: the "future" rate of clk's parent * * Walks the subtree of clks starting with clk, speculating rates as it * goes and firing off PRE_RATE_CHANGE notifications as necessary. * * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending * pre-rate change notifications and returns early if no clks in the * subtree have subscribed to the notifications. Note that if a clk does not * implement the .recalc_rate callback then it is assumed that the clock will * take on the rate of its parent.
*/ staticint __clk_speculate_rates(struct clk_core *core, unsignedlong parent_rate)
{ struct clk_core *child; unsignedlong new_rate; int ret = NOTIFY_DONE;
lockdep_assert_held(&prepare_lock);
new_rate = clk_recalc(core, parent_rate);
/* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */ if (core->notifier_count)
ret = __clk_notify(core, PRE_RATE_CHANGE, core->rate, new_rate);
if (ret & NOTIFY_STOP_MASK) {
pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
__func__, core->name, ret); goto out;
}
hlist_for_each_entry(child, &core->children, child_node) {
ret = __clk_speculate_rates(child, new_rate); if (ret & NOTIFY_STOP_MASK) break;
}
/* some clocks must be gated to change parent */ if (parent != old_parent &&
(core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
pr_debug("%s: %s not gated but wants to reparent\n",
__func__, core->name); return NULL;
}
/* try finding the new parent index */ if (parent && core->num_parents > 1) {
p_index = clk_fetch_parent_index(core, parent); if (p_index < 0) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, core->name); return NULL;
}
}
if ((core->flags & CLK_SET_RATE_PARENT) && parent &&
best_parent_rate != parent->rate)
top = clk_calc_new_rates(parent, best_parent_rate);
/* * Notify about rate changes in a subtree. Always walk down the whole tree * so that in case of an error we can walk down the whole tree again and * abort the change.
*/ staticstruct clk_core *clk_propagate_rate_change(struct clk_core *core, unsignedlong event)
{ struct clk_core *child, *tmp_clk, *fail_clk = NULL; int ret = NOTIFY_DONE;
if (core->rate == core->new_rate) return NULL;
if (core->notifier_count) {
ret = __clk_notify(core, event, core->rate, core->new_rate); if (ret & NOTIFY_STOP_MASK)
fail_clk = core;
}
hlist_for_each_entry(child, &core->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != core) continue;
tmp_clk = clk_propagate_rate_change(child, event); if (tmp_clk)
fail_clk = tmp_clk;
}
/* handle the new child who might not be in core->children yet */ if (core->new_child) {
tmp_clk = clk_propagate_rate_change(core->new_child, event); if (tmp_clk)
fail_clk = tmp_clk;
}
return fail_clk;
}
/* * walk down a subtree and set the new rates notifying the rate * change on the way
*/ staticvoid clk_change_rate(struct clk_core *core)
{ struct clk_core *child; struct hlist_node *tmp; unsignedlong old_rate; unsignedlong best_parent_rate = 0; bool skip_set_rate = false; struct clk_core *old_parent; struct clk_core *parent = NULL;
if (core->flags & CLK_SET_RATE_UNGATE) {
clk_core_disable_lock(core);
clk_core_unprepare(core);
}
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(parent);
if (core->notifier_count && old_rate != core->rate)
__clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate);
if (core->flags & CLK_RECALC_NEW_RATES)
(void)clk_calc_new_rates(core, core->new_rate);
/* * Use safe iteration, as change_rate can actually swap parents * for certain clock types.
*/
hlist_for_each_entry_safe(child, tmp, &core->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != core) continue;
clk_change_rate(child);
}
/* handle the new child who might not be in core->children yet */ if (core->new_child)
clk_change_rate(core->new_child);
/* bail early if nothing to do */ if (rate == clk_core_get_rate_nolock(core)) return 0;
/* fail on a direct rate set of a protected provider */ if (clk_core_rate_is_protected(core)) return -EBUSY;
/* calculate new rates and get the topmost changed clock */
top = clk_calc_new_rates(core, req_rate); if (!top) return -EINVAL;
ret = clk_pm_runtime_get(core); if (ret) return ret;
/* notify that we are about to change rates */
fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); if (fail_clk) {
pr_debug("%s: failed to set %s rate\n", __func__,
fail_clk->name);
clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
ret = -EBUSY; goto err;
}
/** * clk_set_rate - specify a new rate for clk * @clk: the clk whose rate is being changed * @rate: the new rate for clk * * In the simplest case clk_set_rate will only adjust the rate of clk. * * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to * propagate up to clk's parent; whether or not this happens depends on the * outcome of clk's .round_rate implementation. If *parent_rate is unchanged * after calling .round_rate then upstream parent propagation is ignored. If * *parent_rate comes back with a new rate for clk's parent then we propagate * up to clk's parent and set its rate. Upward propagation will continue * until either a clk does not support the CLK_SET_RATE_PARENT flag or * .round_rate stops requesting changes to clk's parent_rate. * * Rate changes are accomplished via tree traversal that also recalculates the * rates for the clocks and fires off POST_RATE_CHANGE notifiers. * * Returns 0 on success, -EERROR otherwise.
*/ int clk_set_rate(struct clk *clk, unsignedlong rate)
{ int ret;
if (!clk) return 0;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
ret = clk_core_set_rate_nolock(clk->core, rate);
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate);
/** * clk_set_rate_exclusive - specify a new rate and get exclusive control * @clk: the clk whose rate is being changed * @rate: the new rate for clk * * This is a combination of clk_set_rate() and clk_rate_exclusive_get() * within a critical section * * This can be used initially to ensure that at least 1 consumer is * satisfied when several consumers are competing for exclusivity over the * same clock provider. * * The exclusivity is not applied if setting the rate failed. * * Calls to clk_rate_exclusive_get() should be balanced with calls to * clk_rate_exclusive_put(). * * Returns 0 on success, -EERROR otherwise.
*/ int clk_set_rate_exclusive(struct clk *clk, unsignedlong rate)
{ int ret;
if (!clk) return 0;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
/* * The temporary protection removal is not here, on purpose * This function is meant to be used instead of clk_rate_protect, * so before the consumer code path protect the clock provider
*/
ret = clk_core_set_rate_nolock(clk->core, rate); if (!ret) {
clk_core_rate_protect(clk->core);
clk->exclusive_count++;
}
staticint clk_set_rate_range_nolock(struct clk *clk, unsignedlong min, unsignedlong max)
{ int ret = 0; unsignedlong old_min, old_max, rate;
lockdep_assert_held(&prepare_lock);
if (!clk) return 0;
trace_clk_set_rate_range(clk->core, min, max);
if (min > max) {
pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
__func__, clk->core->name, clk->dev_id, clk->con_id,
min, max); return -EINVAL;
}
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
/* Save the current values in case we need to rollback the change */
old_min = clk->min_rate;
old_max = clk->max_rate;
clk->min_rate = min;
clk->max_rate = max;
if (!clk_core_check_boundaries(clk->core, min, max)) {
ret = -EINVAL; goto out;
}
rate = clk->core->req_rate; if (clk->core->flags & CLK_GET_RATE_NOCACHE)
rate = clk_core_get_rate_recalc(clk->core);
/* * Since the boundaries have been changed, let's give the * opportunity to the provider to adjust the clock rate based on * the new boundaries. * * We also need to handle the case where the clock is currently * outside of the boundaries. Clamping the last requested rate * to the current minimum and maximum will also handle this. * * FIXME: * There is a catch. It may fail for the usual reason (clock * broken, clock protected, etc) but also because: * - round_rate() was not favorable and fell on the wrong * side of the boundary * - the determine_rate() callback does not really check for * this corner case when determining the rate
*/
rate = clamp(rate, min, max);
ret = clk_core_set_rate_nolock(clk->core, rate); if (ret) { /* rollback the changes */
clk->min_rate = old_min;
clk->max_rate = old_max;
}
out: if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
return ret;
}
/** * clk_set_rate_range - set a rate range for a clock source * @clk: clock source * @min: desired minimum clock rate in Hz, inclusive * @max: desired maximum clock rate in Hz, inclusive * * Return: 0 for success or negative errno on failure.
*/ int clk_set_rate_range(struct clk *clk, unsignedlong min, unsignedlong max)
{ int ret;
/** * clk_set_max_rate - set a maximum clock rate for a clock source * @clk: clock source * @rate: desired maximum clock rate in Hz, inclusive * * Returns success (0) or negative errno.
*/ int clk_set_max_rate(struct clk *clk, unsignedlong rate)
{ if (!clk) return 0;
/** * clk_has_parent - check if a clock is a possible parent for another * @clk: clock source * @parent: parent clock source * * This function can be used in drivers that need to check that a clock can be * the parent of another without actually changing the parent. * * Returns true if @parent is a possible parent for @clk, false otherwise.
*/ bool clk_has_parent(conststruct clk *clk, conststruct clk *parent)
{ /* NULL clocks should be nops, so return success if either is NULL. */ if (!clk || !parent) returntrue;
staticint clk_core_set_parent_nolock(struct clk_core *core, struct clk_core *parent)
{ int ret = 0; int p_index = 0; unsignedlong p_rate = 0;
lockdep_assert_held(&prepare_lock);
if (!core) return 0;
if (core->parent == parent) return 0;
/* verify ops for multi-parent clks */ if (core->num_parents > 1 && !core->ops->set_parent) return -EPERM;
/* check that we are allowed to re-parent if the clock is in use */ if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) return -EBUSY;
if (clk_core_rate_is_protected(core)) return -EBUSY;
/* try finding the new parent index */ if (parent) {
p_index = clk_fetch_parent_index(core, parent); if (p_index < 0) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, core->name); return p_index;
}
p_rate = parent->rate;
}
ret = clk_pm_runtime_get(core); if (ret) return ret;
/* propagate PRE_RATE_CHANGE notifications */
ret = __clk_speculate_rates(core, p_rate);
/* abort if a driver objects */ if (ret & NOTIFY_STOP_MASK) goto runtime_put;
/* do the re-parent */
ret = __clk_set_parent(core, parent, p_index);
/** * clk_set_parent - switch the parent of a mux clk * @clk: the mux clk whose input we are switching * @parent: the new input to clk * * Re-parent clk to use parent as its new input source. If clk is in * prepared state, the clk will get enabled for the duration of this call. If * that's not acceptable for a specific clk (Eg: the consumer can't handle * that, the reparenting is glitchy in hardware, etc), use the * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared. * * After successfully changing clk's parent clk_set_parent will update the * clk topology, sysfs topology and propagate rate recalculation via * __clk_recalc_rates. * * Returns 0 on success, -EERROR otherwise.
*/ int clk_set_parent(struct clk *clk, struct clk *parent)
{ int ret;
if (!clk) return 0;
clk_prepare_lock();
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
ret = clk_core_set_parent_nolock(clk->core,
parent ? parent->core : NULL);
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);
staticint clk_core_set_phase_nolock(struct clk_core *core, int degrees)
{ int ret = -EINVAL;
lockdep_assert_held(&prepare_lock);
if (!core) return 0;
if (clk_core_rate_is_protected(core)) return -EBUSY;
trace_clk_set_phase(core, degrees);
if (core->ops->set_phase) {
ret = core->ops->set_phase(core->hw, degrees); if (!ret)
core->phase = degrees;
}
trace_clk_set_phase_complete(core, degrees);
return ret;
}
/** * clk_set_phase - adjust the phase shift of a clock signal * @clk: clock signal source * @degrees: number of degrees the signal is shifted * * Shifts the phase of a clock signal by the specified * degrees. Returns 0 on success, -EERROR otherwise. * * This function makes no distinction about the input or reference * signal that we adjust the clock signal phase against. For example * phase locked-loop clock signal generators we may shift phase with * respect to feedback clock signal input, but for other cases the * clock phase may be shifted with respect to some other, unspecified * signal. * * Additionally the concept of phase shift does not propagate through * the clock tree hierarchy, which sets it apart from clock rates and * clock accuracy. A parent clock phase attribute does not have an * impact on the phase attribute of a child clock.
*/ int clk_set_phase(struct clk *clk, int degrees)
{ int ret;
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
ret = clk_core_set_phase_nolock(clk->core, degrees);
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_phase);
staticint clk_core_get_phase(struct clk_core *core)
{ int ret;
lockdep_assert_held(&prepare_lock); if (!core->ops->get_phase) return 0;
/* Always try to update cached phase if possible */
ret = core->ops->get_phase(core->hw); if (ret >= 0)
core->phase = ret;
return ret;
}
/** * clk_get_phase - return the phase shift of a clock signal * @clk: clock signal source * * Returns the phase shift of a clock node in degrees, otherwise returns * -EERROR.
*/ int clk_get_phase(struct clk *clk)
{ int ret;
if (!clk) return 0;
clk_prepare_lock();
ret = clk_core_get_phase(clk->core);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_get_phase);
staticvoid clk_core_reset_duty_cycle_nolock(struct clk_core *core)
{ /* Assume a default value of 50% */
core->duty.num = 1;
core->duty.den = 2;
}
staticint clk_core_set_duty_cycle_nolock(struct clk_core *core, struct clk_duty *duty)
{ int ret;
lockdep_assert_held(&prepare_lock);
if (clk_core_rate_is_protected(core)) return -EBUSY;
trace_clk_set_duty_cycle(core, duty);
if (!core->ops->set_duty_cycle) return clk_core_set_duty_cycle_parent_nolock(core, duty);
ret = core->ops->set_duty_cycle(core->hw, duty); if (!ret)
memcpy(&core->duty, duty, sizeof(*duty));
trace_clk_set_duty_cycle_complete(core, duty);
return ret;
}
staticint clk_core_set_duty_cycle_parent_nolock(struct clk_core *core, struct clk_duty *duty)
{ int ret = 0;
if (core->parent &&
core->flags & (CLK_DUTY_CYCLE_PARENT | CLK_SET_RATE_PARENT)) {
ret = clk_core_set_duty_cycle_nolock(core->parent, duty);
memcpy(&core->duty, &core->parent->duty, sizeof(core->duty));
}
return ret;
}
/** * clk_set_duty_cycle - adjust the duty cycle ratio of a clock signal * @clk: clock signal source * @num: numerator of the duty cycle ratio to be applied * @den: denominator of the duty cycle ratio to be applied * * Apply the duty cycle ratio if the ratio is valid and the clock can * perform this operation * * Returns (0) on success, a negative errno otherwise.
*/ int clk_set_duty_cycle(struct clk *clk, unsignedint num, unsignedint den)
{ int ret; struct clk_duty duty;
if (!clk) return 0;
/* sanity check the ratio */ if (den == 0 || num > den) return -EINVAL;
duty.num = num;
duty.den = den;
clk_prepare_lock();
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
ret = clk_core_set_duty_cycle_nolock(clk->core, &duty);
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
ret = clk_core_update_duty_cycle_nolock(core); if (!ret)
ret = mult_frac(scale, duty->num, duty->den);
clk_prepare_unlock();
return ret;
}
/** * clk_get_scaled_duty_cycle - return the duty cycle ratio of a clock signal * @clk: clock signal source * @scale: scaling factor to be applied to represent the ratio as an integer * * Returns the duty cycle ratio of a clock node multiplied by the provided * scaling factor, or negative errno on error.
*/ int clk_get_scaled_duty_cycle(struct clk *clk, unsignedint scale)
{ if (!clk) return 0;
/** * clk_is_match - check if two clk's point to the same hardware clock * @p: clk compared against q * @q: clk compared against p * * Returns true if the two struct clk pointers both point to the same hardware * clock node. Put differently, returns true if struct clk *p and struct clk *q * share the same struct clk_core object. * * Returns false otherwise. Note that two NULL clks are treated as matching.
*/ bool clk_is_match(conststruct clk *p, conststruct clk *q)
{ /* trivial case: identical struct clk's or both NULL */ if (p == q) returntrue;
/* true if clk->core pointers match. Avoid dereferencing garbage */ if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q)) if (p->core == q->core) returntrue;
#undef CLOCK_ALLOW_WRITE_DEBUGFS #ifdef CLOCK_ALLOW_WRITE_DEBUGFS /* * This can be dangerous, therefore don't provide any real compile time * configuration option for this feature. * People who want to use this will need to modify the source code directly.
*/ staticint clk_rate_set(void *data, u64 val)
{ struct clk_core *core = data; int ret;
clk_prepare_lock();
ret = clk_core_set_rate_nolock(core, val);
clk_prepare_unlock();
return ret;
}
#define clk_rate_mode 0644
staticint clk_phase_set(void *data, u64 val)
{ struct clk_core *core = data; int degrees = do_div(val, 360); int ret;
clk_prepare_lock();
ret = clk_core_set_phase_nolock(core, degrees);
clk_prepare_unlock();
return ret;
}
#define clk_phase_mode 0644
staticint clk_prepare_enable_set(void *data, u64 val)
{ struct clk_core *core = data; int ret = 0;
if (val)
ret = clk_prepare_enable(core->hw->clk); else
clk_disable_unprepare(core->hw->clk);
/* * Go through the following options to fetch a parent's name. * * 1. Fetch the registered parent clock and use its name * 2. Use the global (fallback) name if specified * 3. Use the local fw_name if provided * 4. Fetch parent clock's clock-output-name if DT index was set * * This may still fail in some cases, such as when the parent is * specified directly via a struct clk_hw pointer, but it isn't * registered (yet).
*/
parent = clk_core_get_parent_by_index(core, i); if (parent) {
seq_puts(s, parent->name);
} elseif (core->parents[i].name) {
seq_puts(s, core->parents[i].name);
} elseif (core->parents[i].fw_name) {
seq_printf(s, "<%s>(fw)", core->parents[i].fw_name);
} else { if (core->parents[i].index >= 0)
name = of_clk_get_parent_name(core->of_node, core->parents[i].index); if (!name)
name = "(missing)";
if (core->num_parents > 1)
debugfs_create_file("clk_parent", 0644, root, core,
¤t_parent_rw_fops); else #endif if (core->num_parents > 0)
debugfs_create_file("clk_parent", 0444, root, core,
¤t_parent_fops);
if (core->num_parents > 1)
debugfs_create_file("clk_possible_parents", 0444, root, core,
&possible_parents_fops);
if (core->ops->debug_init)
core->ops->debug_init(core->hw, core->dentry);
}
/** * clk_debug_register - add a clk node to the debugfs clk directory * @core: the clk being added to the debugfs clk directory * * Dynamically adds a clk to the debugfs clk directory if debugfs has been * initialized. Otherwise it bails out early since the debugfs clk directory * will be created lazily by clk_debug_init as part of a late_initcall.
*/ staticvoid clk_debug_register(struct clk_core *core)
{
mutex_lock(&clk_debug_lock);
hlist_add_head(&core->debug_node, &clk_debug_list); if (inited)
clk_debug_create_one(core, rootdir);
mutex_unlock(&clk_debug_lock);
}
/** * clk_debug_unregister - remove a clk node from the debugfs clk directory * @core: the clk being removed from the debugfs clk directory * * Dynamically removes a clk and all its child nodes from the * debugfs clk directory if clk->dentry points to debugfs created by * clk_debug_register in __clk_core_init.
*/ staticvoid clk_debug_unregister(struct clk_core *core)
{
mutex_lock(&clk_debug_lock);
hlist_del_init(&core->debug_node);
debugfs_remove_recursive(core->dentry);
core->dentry = NULL;
mutex_unlock(&clk_debug_lock);
}
/** * clk_debug_init - lazily populate the debugfs clk directory * * clks are often initialized very early during boot before memory can be * dynamically allocated and well before debugfs is setup. This function * populates the debugfs clk directory once at boot-time when we know that * debugfs is setup. It should only be called once at boot-time, all other clks * added dynamically will be done so with clk_debug_register.
*/ staticint __init clk_debug_init(void)
{ struct clk_core *core;
#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
pr_warn("\n");
pr_warn("********************************************************************\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("** **\n");
pr_warn("** WRITEABLE clk DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL **\n");
pr_warn("** **\n");
pr_warn("** This means that this kernel is built to expose clk operations **\n");
pr_warn("** such as parent or rate setting, enabling, disabling, etc. **\n");
pr_warn("** to userspace, which may compromise security on your system. **\n");
pr_warn("** **\n");
pr_warn("** If you see this message and you are not debugging the **\n");
pr_warn("** kernel, report this immediately to your vendor! **\n");
pr_warn("** **\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("********************************************************************\n"); #endif
/* * walk the list of orphan clocks and reparent any that newly finds a * parent.
*/
hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { struct clk_core *parent = __clk_init_parent(orphan);
/* * We need to use __clk_set_parent_before() and _after() to * properly migrate any prepare/enable count of the orphan * clock. This is important for CLK_IS_CRITICAL clocks, which * are enabled during init but might not have a parent yet.
*/ if (parent) { /* update the clk tree topology */
__clk_set_parent_before(orphan, parent);
__clk_set_parent_after(orphan, parent, NULL);
__clk_recalc_accuracies(orphan);
__clk_recalc_rates(orphan, true, 0);
/* * __clk_init_parent() will set the initial req_rate to * 0 if the clock doesn't have clk_ops::recalc_rate and * is an orphan when it's registered. * * 'req_rate' is used by clk_set_rate_range() and * clk_put() to trigger a clk_set_rate() call whenever * the boundaries are modified. Let's make sure * 'req_rate' is set to something non-zero so that * clk_set_rate_range() doesn't drop the frequency.
*/
orphan->req_rate = orphan->rate;
}
}
}
/** * __clk_core_init - initialize the data structures in a struct clk_core * @core: clk_core being initialized * * Initializes the lists in struct clk_core, queries the hardware for the * parent and rate and sets them both.
*/ staticint __clk_core_init(struct clk_core *core)
{ int ret; struct clk_core *parent; unsignedlong rate; int phase;
clk_prepare_lock();
/* * Set hw->core after grabbing the prepare_lock to synchronize with * callers of clk_core_fill_parent_index() where we treat hw->core * being NULL as the clk not being registered yet. This is crucial so * that clks aren't parented until their parent is fully registered.
*/
core->hw->core = core;
ret = clk_pm_runtime_get(core); if (ret) goto unlock;
/* check to see if a clock with this name is already registered */ if (clk_core_lookup(core->name)) {
pr_debug("%s: clk %s already initialized\n",
__func__, core->name);
ret = -EEXIST; goto out;
}
/* check that clk_ops are sane. See Documentation/driver-api/clk.rst */ if (core->ops->set_rate &&
!((core->ops->round_rate || core->ops->determine_rate) &&
core->ops->recalc_rate)) {
pr_err("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
__func__, core->name);
ret = -EINVAL; goto out;
}
if (core->ops->set_parent && !core->ops->get_parent) {
pr_err("%s: %s must implement .get_parent & .set_parent\n",
__func__, core->name);
ret = -EINVAL; goto out;
}
if (core->ops->set_parent && !core->ops->determine_rate) {
pr_err("%s: %s must implement .set_parent & .determine_rate\n",
__func__, core->name);
ret = -EINVAL; goto out;
}
if (core->num_parents > 1 && !core->ops->get_parent) {
pr_err("%s: %s must implement .get_parent as it has multi parents\n",
__func__, core->name);
ret = -EINVAL; goto out;
}
if (core->ops->set_rate_and_parent &&
!(core->ops->set_parent && core->ops->set_rate)) {
pr_err("%s: %s must implement .set_parent & .set_rate\n",
__func__, core->name);
ret = -EINVAL; goto out;
}
/* * optional platform-specific magic * * The .init callback is not used by any of the basic clock types, but * exists for weird hardware that must perform initialization magic for * CCF to get an accurate view of clock for any other callbacks. It may * also be used needs to perform dynamic allocations. Such allocation * must be freed in the terminate() callback. * This callback shall not be used to initialize the parameters state, * such as rate, parent, etc ... * * If it exist, this callback should called before any other callback of * the clock
*/ if (core->ops->init) {
ret = core->ops->init(core->hw); if (ret) goto out;
}
parent = core->parent = __clk_init_parent(core);
/* * Populate core->parent if parent has already been clk_core_init'd. If * parent has not yet been clk_core_init'd then place clk in the orphan * list. If clk doesn't have any parents then place it in the root * clk list. * * Every time a new clk is clk_init'd then we walk the list of orphan * clocks and re-parent any that are children of the clock currently * being clk_init'd.
*/ if (parent) {
hlist_add_head(&core->child_node, &parent->children);
core->orphan = parent->orphan;
} elseif (!core->num_parents) {
hlist_add_head(&core->child_node, &clk_root_list);
core->orphan = false;
} else {
hlist_add_head(&core->child_node, &clk_orphan_list);
core->orphan = true;
}
/* * Set clk's accuracy. The preferred method is to use * .recalc_accuracy. For simple clocks and lazy developers the default * fallback is to use the parent's accuracy. If a clock doesn't have a * parent (or is orphaned) then accuracy is set to zero (perfect * clock).
*/ if (core->ops->recalc_accuracy)
core->accuracy = core->ops->recalc_accuracy(core->hw,
clk_core_get_accuracy_no_lock(parent)); elseif (parent)
core->accuracy = parent->accuracy; else
core->accuracy = 0;
/* * Set clk's phase by clk_core_get_phase() caching the phase. * Since a phase is by definition relative to its parent, just * query the current clock phase, or just assume it's in phase.
*/
phase = clk_core_get_phase(core); if (phase < 0) {
ret = phase;
pr_warn("%s: Failed to get phase for clk '%s'\n", __func__,
core->name); goto out;
}
/* * Set clk's duty cycle.
*/
clk_core_update_duty_cycle_nolock(core);
/* * Set clk's rate. The preferred method is to use .recalc_rate. For * simple clocks and lazy developers the default fallback is to use the * parent's rate. If a clock doesn't have a parent (or is orphaned) * then rate is set to zero.
*/ if (core->ops->recalc_rate)
rate = core->ops->recalc_rate(core->hw,
clk_core_get_rate_nolock(parent)); elseif (parent)
rate = parent->rate; else
rate = 0;
core->rate = core->req_rate = rate;
/* * Enable CLK_IS_CRITICAL clocks so newly added critical clocks * don't get accidentally disabled when walking the orphan tree and * reparenting clocks
*/ if (core->flags & CLK_IS_CRITICAL) {
ret = clk_core_prepare(core); if (ret) {
pr_warn("%s: critical clk '%s' failed to prepare\n",
__func__, core->name); goto out;
}
ret = clk_core_enable_lock(core); if (ret) {
pr_warn("%s: critical clk '%s' failed to enable\n",
__func__, core->name);
clk_core_unprepare(core); goto out;
}
}
/** * clk_core_link_consumer - Add a clk consumer to the list of consumers in a clk_core * @core: clk to add consumer to * @clk: consumer to link to a clk
*/ staticvoid clk_core_link_consumer(struct clk_core *core, struct clk *clk)
{
clk_prepare_lock();
hlist_add_head(&clk->clks_node, &core->clks);
clk_prepare_unlock();
}
/** * clk_core_unlink_consumer - Remove a clk consumer from the list of consumers in a clk_core * @clk: consumer to unlink
*/ staticvoid clk_core_unlink_consumer(struct clk *clk)
{
lockdep_assert_held(&prepare_lock);
hlist_del(&clk->clks_node);
}
/** * alloc_clk - Allocate a clk consumer, but leave it unlinked to the clk_core * @core: clk to allocate a consumer for * @dev_id: string describing device name * @con_id: connection ID string on device * * Returns: clk consumer left unlinked from the consumer list
*/ staticstruct clk *alloc_clk(struct clk_core *core, constchar *dev_id, constchar *con_id)
{ struct clk *clk;
clk = kzalloc(sizeof(*clk), GFP_KERNEL); if (!clk) return ERR_PTR(-ENOMEM);
/** * free_clk - Free a clk consumer * @clk: clk consumer to free * * Note, this assumes the clk has been unlinked from the clk_core consumer * list.
*/ staticvoid free_clk(struct clk *clk)
{
kfree_const(clk->con_id);
kfree(clk);
}
/** * clk_hw_create_clk: Allocate and link a clk consumer to a clk_core given * a clk_hw * @dev: clk consumer device * @hw: clk_hw associated with the clk being consumed * @dev_id: string describing device name * @con_id: connection ID string on device * * This is the main function used to create a clk pointer for use by clk * consumers. It connects a consumer to the clk_core and clk_hw structures * used by the framework and clk provider respectively.
*/ struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw, constchar *dev_id, constchar *con_id)
{ struct clk *clk; struct clk_core *core;
/* This is to allow this function to be chained to others */ if (IS_ERR_OR_NULL(hw)) return ERR_CAST(hw);
/** * clk_hw_get_clk - get clk consumer given an clk_hw * @hw: clk_hw associated with the clk being consumed * @con_id: connection ID string on device * * Returns: new clk consumer * This is the function to be used by providers which need * to get a consumer clk and act on the clock element * Calls to this function must be balanced with calls clk_put()
*/ struct clk *clk_hw_get_clk(struct clk_hw *hw, constchar *con_id)
{ struct device *dev = hw->core->dev; constchar *name = dev ? dev_name(dev) : NULL;
/* * Avoid unnecessary string look-ups of clk_core's possible parents by * having a cache of names/clk_hw pointers to clk_core pointers.
*/
parents = kcalloc(num_parents, sizeof(*parents), GFP_KERNEL);
core->parents = parents; if (!parents) return -ENOMEM;
/* Copy everything over because it might be __initdata */ for (i = 0, parent = parents; i < num_parents; i++, parent++) {
parent->index = -1; if (parent_names) { /* throw a WARN if any entries are NULL */
WARN(!parent_names[i], "%s: invalid NULL in %s's .parent_names\n",
__func__, core->name);
ret = clk_cpy_name(&parent->name, parent_names[i], true);
} elseif (parent_data) {
parent->hw = parent_data[i].hw;
parent->index = parent_data[i].index;
ret = clk_cpy_name(&parent->fw_name,
parent_data[i].fw_name, false); if (!ret)
ret = clk_cpy_name(&parent->name,
parent_data[i].name, false);
} elseif (parent_hws) {
parent->hw = parent_hws[i];
} else {
ret = -EINVAL;
WARN(1, "Must specify parents if num_parents > 0\n");
}
if (ret) { do {
kfree_const(parents[i].name);
kfree_const(parents[i].fw_name);
} while (--i >= 0);
kfree(parents);
return ret;
}
}
return 0;
}
staticvoid clk_core_free_parent_map(struct clk_core *core)
{ int i = core->num_parents;
if (!core->num_parents) return;
while (--i >= 0) {
kfree_const(core->parents[i].name);
kfree_const(core->parents[i].fw_name);
}
/* * The init data is not supposed to be used outside of registration path. * Set it to NULL so that provider drivers can't use it either and so that * we catch use of hw->init early on in the core.
*/
hw->init = NULL;
core = kzalloc(sizeof(*core), GFP_KERNEL); if (!core) {
ret = -ENOMEM; goto fail_out;
}
kref_init(&core->ref);
core->name = kstrdup_const(init->name, GFP_KERNEL); if (!core->name) {
ret = -ENOMEM; goto fail_name;
}
if (WARN_ON(!init->ops)) {
ret = -EINVAL; goto fail_ops;
}
core->ops = init->ops;
ret = clk_core_populate_parent_map(core, init); if (ret) goto fail_parents;
INIT_HLIST_HEAD(&core->clks);
/* * Don't call clk_hw_create_clk() here because that would pin the * provider module to itself and prevent it from ever being removed.
*/
hw->clk = alloc_clk(core, NULL, NULL); if (IS_ERR(hw->clk)) {
ret = PTR_ERR(hw->clk); goto fail_create_clk;
}
clk_core_link_consumer(core, hw->clk);
ret = __clk_core_init(core); if (!ret) return hw->clk;
/** * dev_or_parent_of_node() - Get device node of @dev or @dev's parent * @dev: Device to get device node of * * Return: device node pointer of @dev, or the device node pointer of * @dev->parent if dev doesn't have a device node, or NULL if neither * @dev or @dev->parent have a device node.
*/ staticstruct device_node *dev_or_parent_of_node(struct device *dev)
{ struct device_node *np;
if (!dev) return NULL;
np = dev_of_node(dev); if (!np)
np = dev_of_node(dev->parent);
return np;
}
/** * clk_register - allocate a new clock, register it and return an opaque cookie * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * clk_register is the *deprecated* interface for populating the clock tree with * new clock nodes. Use clk_hw_register() instead. * * Returns: a pointer to the newly allocated struct clk which * cannot be dereferenced by driver code but may be used in conjunction with the * rest of the clock API. In the event of an error clk_register will return an * error code; drivers must test for an error code after calling clk_register.
*/ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
{ return __clk_register(dev, dev_or_parent_of_node(dev), hw);
}
EXPORT_SYMBOL_GPL(clk_register);
/** * clk_hw_register - register a clk_hw and return an error code * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * clk_hw_register is the primary interface for populating the clock tree with * new clock nodes. It returns an integer equal to zero indicating success or * less than zero indicating failure. Drivers must test for an error code after * calling clk_hw_register().
*/ int clk_hw_register(struct device *dev, struct clk_hw *hw)
{ return PTR_ERR_OR_ZERO(__clk_register(dev, dev_or_parent_of_node(dev),
hw));
}
EXPORT_SYMBOL_GPL(clk_hw_register);
/* * of_clk_hw_register - register a clk_hw and return an error code * @node: device_node of device that is registering this clock * @hw: link to hardware-specific clock data * * of_clk_hw_register() is the primary interface for populating the clock tree * with new clock nodes when a struct device is not available, but a struct * device_node is. It returns an integer equal to zero indicating success or * less than zero indicating failure. Drivers must test for an error code after * calling of_clk_hw_register().
*/ int of_clk_hw_register(struct device_node *node, struct clk_hw *hw)
{ return PTR_ERR_OR_ZERO(__clk_register(NULL, node, hw));
}
EXPORT_SYMBOL_GPL(of_clk_hw_register);
/* * Empty clk_ops for unregistered clocks. These are used temporarily * after clk_unregister() was called on a clock and until last clock * consumer calls clk_put() and the struct clk object is freed.
*/ staticint clk_nodrv_prepare_enable(struct clk_hw *hw)
{ return -ENXIO;
}
/** * clk_unregister - unregister a currently registered clock * @clk: clock to unregister
*/ void clk_unregister(struct clk *clk)
{ unsignedlong flags; conststruct clk_ops *ops;
if (!clk || WARN_ON_ONCE(IS_ERR(clk))) return;
clk_debug_unregister(clk->core);
clk_prepare_lock();
ops = clk->core->ops; if (ops == &clk_nodrv_ops) {
pr_err("%s: unregistered clock: %s\n", __func__,
clk->core->name);
clk_prepare_unlock(); return;
} /* * Assign empty clock ops for consumers that might still hold * a reference to this clock.
*/
flags = clk_enable_lock();
clk->core->ops = &clk_nodrv_ops;
clk_enable_unlock(flags);
if (ops->terminate)
ops->terminate(clk->core->hw);
if (!hlist_empty(&clk->core->children)) { struct clk_core *child; struct hlist_node *t;
/* Reparent all children to the orphan list. */
hlist_for_each_entry_safe(child, t, &clk->core->children,
child_node)
clk_core_set_parent_nolock(child, NULL);
}
clk_core_evict_parent_cache(clk->core);
hlist_del_init(&clk->core->child_node);
if (clk->core->prepare_count)
pr_warn("%s: unregistering prepared clock: %s\n",
__func__, clk->core->name);
if (clk->core->protect_count)
pr_warn("%s: unregistering protected clock: %s\n",
__func__, clk->core->name);
clk_prepare_unlock();
/** * devm_clk_register - resource managed clk_register() * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * Managed clk_register(). This function is *deprecated*, use devm_clk_hw_register() instead. * * Clocks returned from this function are automatically clk_unregister()ed on * driver detach. See clk_register() for more information.
*/ struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
{ struct clk *clk; struct clk **clkp;
clkp = devres_alloc(devm_clk_unregister_cb, sizeof(*clkp), GFP_KERNEL); if (!clkp) return ERR_PTR(-ENOMEM);
/** * devm_clk_hw_register - resource managed clk_hw_register() * @dev: device that is registering this clock * @hw: link to hardware-specific clock data * * Managed clk_hw_register(). Clocks registered by this function are * automatically clk_hw_unregister()ed on driver detach. See clk_hw_register() * for more information.
*/ int devm_clk_hw_register(struct device *dev, struct clk_hw *hw)
{ struct clk_hw **hwp; int ret;
hwp = devres_alloc(devm_clk_hw_unregister_cb, sizeof(*hwp), GFP_KERNEL); if (!hwp) return -ENOMEM;
ret = clk_hw_register(dev, hw); if (!ret) {
*hwp = hw;
devres_add(dev, hwp);
} else {
devres_free(hwp);
}
/** * devm_clk_hw_get_clk - resource managed clk_hw_get_clk() * @dev: device that is registering this clock * @hw: clk_hw associated with the clk being consumed * @con_id: connection ID string on device * * Managed clk_hw_get_clk(). Clocks got with this function are * automatically clk_put() on driver detach. See clk_put() * for more information.
*/ struct clk *devm_clk_hw_get_clk(struct device *dev, struct clk_hw *hw, constchar *con_id)
{ struct clk *clk; struct clk **clkp;
/* This should not happen because it would mean we have drivers * passing around clk_hw pointers instead of having the caller use * proper clk_get() style APIs
*/
WARN_ON_ONCE(dev != hw->core->dev);
clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL); if (!clkp) return ERR_PTR(-ENOMEM);
/* * Before calling clk_put, all calls to clk_rate_exclusive_get() from a * given user should be balanced with calls to clk_rate_exclusive_put() * and by that same consumer
*/ if (WARN_ON(clk->exclusive_count)) { /* We voiced our concern, let's sanitize the situation */
clk->core->protect_count -= (clk->exclusive_count - 1);
clk_core_rate_unprotect(clk->core);
clk->exclusive_count = 0;
}
clk_core_unlink_consumer(clk);
/* If we had any boundaries on that clock, let's drop them. */ if (clk->min_rate > 0 || clk->max_rate < ULONG_MAX)
clk_set_rate_range_nolock(clk, 0, ULONG_MAX);
/** * clk_notifier_register - add a clk rate change notifier * @clk: struct clk * to watch * @nb: struct notifier_block * with callback info * * Request notification when clk's rate changes. This uses an SRCU * notifier because we want it to block and notifier unregistrations are * uncommon. The callbacks associated with the notifier must not * re-enter into the clk framework by calling any top-level clk APIs; * this will cause a nested prepare_lock mutex. * * In all notification cases (pre, post and abort rate change) the original * clock rate is passed to the callback via struct clk_notifier_data.old_rate * and the new frequency is passed via struct clk_notifier_data.new_rate. * * clk_notifier_register() must be called from non-atomic context. * Returns -EINVAL if called with null arguments, -ENOMEM upon * allocation failure; otherwise, passes along the return value of * srcu_notifier_chain_register().
*/ int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
{ struct clk_notifier *cn; int ret = -ENOMEM;
if (!clk || !nb) return -EINVAL;
clk_prepare_lock();
/* search the list of notifiers for this clk */
list_for_each_entry(cn, &clk_notifier_list, node) if (cn->clk == clk) goto found;
/* if clk wasn't in the notifier list, allocate new clk_notifier */
cn = kzalloc(sizeof(*cn), GFP_KERNEL); if (!cn) goto out;
/** * clk_notifier_unregister - remove a clk rate change notifier * @clk: struct clk * * @nb: struct notifier_block * with callback info * * Request no further notification for changes to 'clk' and frees memory * allocated in clk_notifier_register. * * Returns -EINVAL if called with null arguments; otherwise, passes * along the return value of srcu_notifier_chain_unregister().
*/ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
{ struct clk_notifier *cn; int ret = -ENOENT;
if (!clk || !nb) return -EINVAL;
clk_prepare_lock();
list_for_each_entry(cn, &clk_notifier_list, node) { if (cn->clk == clk) {
ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
clk->core->notifier_count--;
/* XXX the notifier code should handle this better */ if (!cn->notifier_head.head) {
srcu_cleanup_notifier_head(&cn->notifier_head);
list_del(&cn->node);
kfree(cn);
} break;
}
}
/** * struct of_clk_provider - Clock provider registration structure * @link: Entry in global list of clock providers * @node: Pointer to device tree node of clock provider * @get: Get clock callback. Returns NULL or a struct clk for the * given clock specifier * @get_hw: Get clk_hw callback. Returns NULL, ERR_PTR or a * struct clk_hw for the given clock specifier * @data: context pointer to be passed into @get callback
*/ struct of_clk_provider { struct list_head link;
/* * We allow a child device to use its parent device as the clock provider node * for cases like MFD sub-devices where the child device driver wants to use * devm_*() APIs but not list the device in DT as a sub-node.
*/ staticstruct device_node *get_clk_provider_node(struct device *dev)
{ struct device_node *np, *parent_np;
if (!of_property_present(np, "#clock-cells")) if (of_property_present(parent_np, "#clock-cells"))
np = parent_np;
return np;
}
/** * devm_of_clk_add_hw_provider() - Managed clk provider node registration * @dev: Device acting as the clock provider (used for DT node and lifetime) * @get: callback for decoding clk_hw * @data: context pointer for @get callback * * Registers clock provider for given device's node. If the device has no DT * node or if the device node lacks of clock provider information (#clock-cells) * then the parent device's node is scanned for this information. If parent node * has the #clock-cells then it is used in registration. Provider is * automatically released at device exit. * * Return: 0 on success or an errno on failure.
*/ int devm_of_clk_add_hw_provider(struct device *dev, struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data), void *data)
{ struct device_node **ptr, *np; int ret;
ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr),
GFP_KERNEL); if (!ptr) return -ENOMEM;
/** * of_parse_clkspec() - Parse a DT clock specifier for a given device node * @np: device node to parse clock specifier from * @index: index of phandle to parse clock out of. If index < 0, @name is used * @name: clock name to find and parse. If name is NULL, the index is used * @out_args: Result of parsing the clock specifier * * Parses a device node's "clocks" and "clock-names" properties to find the * phandle and cells for the index or name that is desired. The resulting clock * specifier is placed into @out_args, or an errno is returned when there's a * parsing error. The @index argument is ignored if @name is non-NULL. * * Example: * * phandle1: clock-controller@1 { * #clock-cells = <2>; * } * * phandle2: clock-controller@2 { * #clock-cells = <1>; * } * * clock-consumer@3 { * clocks = <&phandle1 1 2 &phandle2 3>; * clock-names = "name1", "name2"; * } * * To get a device_node for `clock-controller@2' node you may call this * function a few different ways: * * of_parse_clkspec(clock-consumer@3, -1, "name2", &args); * of_parse_clkspec(clock-consumer@3, 1, NULL, &args); * of_parse_clkspec(clock-consumer@3, 1, "name2", &args); * * Return: 0 upon successfully parsing the clock specifier. Otherwise, -ENOENT * if @name is NULL or -EINVAL if @name is non-NULL and it can't be found in * the "clock-names" property of @np.
*/ staticint of_parse_clkspec(conststruct device_node *np, int index, constchar *name, struct of_phandle_args *out_args)
{ int ret = -ENOENT;
/* Walk up the tree of devices looking for a clock property that matches */ while (np) { /* * For named clocks, first look up the name in the * "clock-names" property. If it cannot be found, then index * will be an error code and of_parse_phandle_with_args() will * return -EINVAL.
*/ if (name)
index = of_property_match_string(np, "clock-names", name);
ret = of_parse_phandle_with_args(np, "clocks", "#clock-cells",
index, out_args); if (!ret) break; if (name && index >= 0) break;
/* * No matching clock found on this node. If the parent node * has a "clock-ranges" property, then we can try one of its * clocks.
*/
np = np->parent; if (np && !of_property_present(np, "clock-ranges")) break;
index = 0;
}
/* Check if node in clkspec is in disabled/fail state */ if (!of_device_is_available(clkspec->np)) return ERR_PTR(-ENOENT);
mutex_lock(&of_clk_mutex);
list_for_each_entry(provider, &of_clk_providers, link) { if (provider->node == clkspec->np) {
hw = __of_clk_get_hw_from_provider(provider, clkspec); if (!IS_ERR(hw)) break;
}
}
mutex_unlock(&of_clk_mutex);
return hw;
}
/** * of_clk_get_from_provider() - Lookup a clock from a clock provider * @clkspec: pointer to a clock specifier data structure * * This function looks up a struct clk from the registered list of clock * providers, an input is a clock specifier data structure as returned * from the of_parse_phandle_with_args() function call.
*/ struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{ struct clk_hw *hw = of_clk_get_hw_from_clkspec(clkspec);
/** * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node * @np: pointer to clock consumer node * @name: name of consumer's clock input, or NULL for the first clock reference * * This function parses the clocks and clock-names properties, * and uses them to look up the struct clk from the registered list of clock * providers.
*/ struct clk *of_clk_get_by_name(struct device_node *np, constchar *name)
{ if (!np) return ERR_PTR(-ENOENT);
/** * of_clk_get_parent_count() - Count the number of clocks a device node has * @np: device node to count * * Returns: The number of clocks that are possible parents of this node
*/ unsignedint of_clk_get_parent_count(conststruct device_node *np)
{ int count;
index = clkspec.args_count ? clkspec.args[0] : 0;
count = 0;
/* if there is an indices property, use it to transfer the index * specified into an array offset for the clock-output-names property.
*/
of_property_for_each_u32(clkspec.np, "clock-indices", pv) { if (index == pv) {
index = count;
found = true; break;
}
count++;
} /* We went off the end of 'clock-indices' without finding it */ if (of_property_present(clkspec.np, "clock-indices") && !found) {
of_node_put(clkspec.np); return NULL;
}
if (of_property_read_string_index(clkspec.np, "clock-output-names",
index,
&clk_name) < 0) { /* * Best effort to get the name if the clock has been * registered with the framework. If the clock isn't * registered, we return the node name as the name of * the clock as long as #clock-cells = 0.
*/
clk = of_clk_get_from_provider(&clkspec); if (IS_ERR(clk)) { if (clkspec.args_count == 0)
clk_name = clkspec.np->name; else
clk_name = NULL;
} else {
clk_name = __clk_get_name(clk);
clk_put(clk);
}
}
/** * of_clk_parent_fill() - Fill @parents with names of @np's parents and return * number of parents * @np: Device node pointer associated with clock provider * @parents: pointer to char array that hold the parents' names * @size: size of the @parents array * * Return: number of parents for the clock node.
*/ int of_clk_parent_fill(struct device_node *np, constchar **parents, unsignedint size)
{ unsignedint i = 0;
while (i < size && (parents[i] = of_clk_get_parent_name(np, i)) != NULL)
i++;
/* * This function looks for a parent clock. If there is one, then it * checks that the provider for this parent clock was initialized, in * this case the parent clock will be ready.
*/ staticint parent_ready(struct device_node *np)
{ int i = 0;
while (true) { struct clk *clk = of_clk_get(np, i);
/* this parent is ready we can check the next one */ if (!IS_ERR(clk)) {
clk_put(clk);
i++; continue;
}
/* at least one parent is not ready, we exit now */ if (PTR_ERR(clk) == -EPROBE_DEFER) return 0;
/* * Here we make assumption that the device tree is * written correctly. So an error means that there is * no more parent. As we didn't exit yet, then the * previous parent are ready. If there is no clock * parent, no need to wait for them, then we can * consider their absence as being ready
*/ return 1;
}
}
/** * of_clk_detect_critical() - set CLK_IS_CRITICAL flag from Device Tree * @np: Device node pointer associated with clock provider * @index: clock index * @flags: pointer to top-level framework flags * * Detects if the clock-critical property exists and, if so, sets the * corresponding CLK_IS_CRITICAL flag. * * Do not use this function. It exists only for legacy Device Tree * bindings, such as the one-clock-per-node style that are outdated. * Those bindings typically put all clock data into .dts and the Linux * driver has no clock data, thus making it impossible to set this flag * correctly from the driver. Only those drivers may call * of_clk_detect_critical from their setup functions. * * Return: error code or zero on success
*/ int of_clk_detect_critical(struct device_node *np, int index, unsignedlong *flags)
{
uint32_t idx;
if (!np || !flags) return -EINVAL;
of_property_for_each_u32(np, "clock-critical", idx) if (index == idx)
*flags |= CLK_IS_CRITICAL;
return 0;
}
/** * of_clk_init() - Scan and init clock providers from the DT * @matches: array of compatible values and init functions for providers. * * This function scans the device tree for matching clock providers * and calls their initialization functions. It also does it by trying * to follow the dependencies.
*/ void __init of_clk_init(conststruct of_device_id *matches)
{ conststruct of_device_id *match; struct device_node *np; struct clock_provider *clk_provider, *next; bool is_init_done; bool force = false;
LIST_HEAD(clk_provider_list);
if (!matches)
matches = &__clk_of_table;
/* First prepare the list of the clocks providers */
for_each_matching_node_and_match(np, matches, &match) { struct clock_provider *parent;
/* * We didn't manage to initialize any of the * remaining providers during the last loop, so now we * initialize all the remaining ones unconditionally * in case the clock parent was not mandatory
*/ if (!is_init_done)
force = true;
}
} #endif
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