Commit dd23c2cd authored by Maxime COQUELIN's avatar Maxime COQUELIN Committed by Mike Turquette
Browse files

clk: divider: Fix best div calculation for power-of-two and table dividers 



The divider returned by clk_divider_bestdiv() is likely to be invalid in case
of power-of-two and table dividers when CLK_SET_RATE_PARENT flag isn't set.

Fixes boot on STiH416 platform.

Signed-off-by: default avatarMaxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: trivial merge conflict & updated changelog]
parent e813d49d

drivers/clk/clk-divider.c

+36 −1
Original line number Diff line number Diff line
@@ -144,6 +144,37 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div) 
	return true;

}



static int _round_up_table(const struct clk_div_table *table, int div)

{

	const struct clk_div_table *clkt;

	int up = _get_table_maxdiv(table);



	for (clkt = table; clkt->div; clkt++) {

		if (clkt->div == div)

			return clkt->div;

		else if (clkt->div < div)

			continue;



		if ((clkt->div - div) < (up - div))

			up = clkt->div;

	}



	return up;

}



static int _div_round_up(struct clk_divider *divider,

		unsigned long parent_rate, unsigned long rate)

{

	int div = DIV_ROUND_UP(parent_rate, rate);



	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)

		div = __roundup_pow_of_two(div);

	if (divider->table)

		div = _round_up_table(divider->table, div);



	return div;

}



static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,

		unsigned long *best_parent_rate)

{
@@ -159,7 +190,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, 


	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {

		parent_rate = *best_parent_rate;

		bestdiv = DIV_ROUND_UP(parent_rate, rate);

		bestdiv = _div_round_up(divider, parent_rate, rate);

		bestdiv = bestdiv == 0 ? 1 : bestdiv;

		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;

		return bestdiv;
@@ -219,6 +250,10 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, 
	u32 val;



	div = DIV_ROUND_UP(parent_rate, rate);



	if (!_is_valid_div(divider, div))

		return -EINVAL;



	value = _get_val(divider, div);



	if (value > div_mask(divider))

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