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clk: Fixup errorhandling for clk_set_parent
Fixup the broken feature of allowing reparent of a clk to the orhpan list and vice verse. When operating on a single-parent clk, the .set_parent callback for the clk hw is optional to implement, but for a multi-parent clk it is mandatory. Moreover improve the errorhandling by verifying the prerequisites before triggering clk notifiers. This will prevent unnecessary rollback with ABORT_RATE_CHANGE. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
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b33d212f49
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@ -1332,15 +1332,10 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent)
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__clk_recalc_rates(clk, POST_RATE_CHANGE);
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}
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static int __clk_set_parent(struct clk *clk, struct clk *parent)
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static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
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{
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struct clk *old_parent;
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unsigned long flags;
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int ret = -EINVAL;
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u8 i;
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old_parent = clk->parent;
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if (!clk->parents)
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clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
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GFP_KERNEL);
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@ -1360,11 +1355,14 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
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}
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}
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if (i == clk->num_parents) {
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pr_debug("%s: clock %s is not a possible parent of clock %s\n",
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__func__, parent->name, clk->name);
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goto out;
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}
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return i;
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}
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static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
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{
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unsigned long flags;
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int ret = 0;
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struct clk *old_parent = clk->parent;
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/* migrate prepare and enable */
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if (clk->prepare_count)
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@ -1377,7 +1375,8 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
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clk_enable_unlock(flags);
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/* change clock input source */
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ret = clk->ops->set_parent(clk->hw, i);
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if (parent && clk->ops->set_parent)
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ret = clk->ops->set_parent(clk->hw, p_index);
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/* clean up old prepare and enable */
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flags = clk_enable_lock();
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@ -1388,7 +1387,6 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
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if (clk->prepare_count)
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__clk_unprepare(old_parent);
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out:
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return ret;
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}
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@ -1407,11 +1405,14 @@ out:
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int clk_set_parent(struct clk *clk, struct clk *parent)
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{
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int ret = 0;
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u8 p_index = 0;
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unsigned long p_rate = 0;
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if (!clk || !clk->ops)
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return -EINVAL;
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if (!clk->ops->set_parent)
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/* verify ops for for multi-parent clks */
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if ((clk->num_parents > 1) && (!clk->ops->set_parent))
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return -ENOSYS;
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/* prevent racing with updates to the clock topology */
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@ -1420,19 +1421,34 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
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if (clk->parent == parent)
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goto out;
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/* check that we are allowed to re-parent if the clock is in use */
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if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
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ret = -EBUSY;
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goto out;
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}
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/* try finding the new parent index */
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if (parent) {
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p_index = clk_fetch_parent_index(clk, parent);
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p_rate = parent->rate;
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if (p_index == clk->num_parents) {
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pr_debug("%s: clk %s can not be parent of clk %s\n",
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__func__, parent->name, clk->name);
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ret = -EINVAL;
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goto out;
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}
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}
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/* propagate PRE_RATE_CHANGE notifications */
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if (clk->notifier_count)
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ret = __clk_speculate_rates(clk, parent->rate);
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ret = __clk_speculate_rates(clk, p_rate);
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/* abort if a driver objects */
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if (ret == NOTIFY_STOP)
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goto out;
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/* only re-parent if the clock is not in use */
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if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
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ret = -EBUSY;
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else
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ret = __clk_set_parent(clk, parent);
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/* do the re-parent */
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ret = __clk_set_parent(clk, parent, p_index);
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/* propagate ABORT_RATE_CHANGE if .set_parent failed */
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if (ret) {
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