forked from Minki/linux
clk: core: clk_calc_new_rates handles NULL parents
It is possible to call clk_set_rate on a clock with a NULL parent. One such example is an adjustable-rate root clock. Ensure that clk_calc_new_rates does not dereference parent without checking first and also handle the corner cases gracefully. Reported-by: Rajendra Nayak <rnayak@ti.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
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@ -763,25 +763,38 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
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static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
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{
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struct clk *top = clk;
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unsigned long best_parent_rate = clk->parent->rate;
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unsigned long best_parent_rate;
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unsigned long new_rate;
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if (!clk->ops->round_rate && !(clk->flags & CLK_SET_RATE_PARENT)) {
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clk->new_rate = clk->rate;
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/* sanity */
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if (IS_ERR_OR_NULL(clk))
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return NULL;
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/* never propagate up to the parent */
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if (!(clk->flags & CLK_SET_RATE_PARENT)) {
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if (!clk->ops->round_rate) {
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clk->new_rate = clk->rate;
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return NULL;
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} else {
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new_rate = clk->ops->round_rate(clk->hw, rate, NULL);
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goto out;
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}
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}
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/* need clk->parent from here on out */
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if (!clk->parent) {
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pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
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return NULL;
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}
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if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) {
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if (!clk->ops->round_rate) {
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top = clk_calc_new_rates(clk->parent, rate);
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new_rate = clk->new_rate = clk->parent->new_rate;
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goto out;
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}
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if (clk->flags & CLK_SET_RATE_PARENT)
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new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
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else
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new_rate = clk->ops->round_rate(clk->hw, rate, NULL);
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new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
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if (best_parent_rate != clk->parent->rate) {
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top = clk_calc_new_rates(clk->parent, best_parent_rate);
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