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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: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: trivial merge conflict & updated changelog]
hifive-unleashed-5.1
Maxime COQUELIN 2014-01-29 17:24:06 +01:00 committed by Mike Turquette
parent e813d49d2a
commit dd23c2cd38
1 changed files with 36 additions and 1 deletions
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37
drivers/clk/clk-divider.c
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@ -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))