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clk: xilinx: Optimize divisor search in clk_wzrd_get_divisors_ver()

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Optimise the clock wizard divisor calculation by eliminating the innermost
loop over output divider o. Earlier there was an error that is returned
if the WZRD_MIN_ERR is not achieved error is returned now it computes
the best possible frequency.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Shubhrajyoti Datta
2025-07-29 10:38:42 +05:30
committed by Stephen Boyd
parent 8f5ae30d69
commit e0a94c6bb5
1 changed files with 17 additions and 13 deletions
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30
drivers/clk/xilinx/clk-xlnx-clock-wizard.c
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@@ -340,7 +340,7 @@ static int clk_wzrd_get_divisors_ver(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
u64 vco_freq, freq, diff, vcomin, vcomax;
u64 vco_freq, freq, diff, vcomin, vcomax, best_diff = -1ULL;
u32 m, d, o;
u32 mmin, mmax, dmin, dmax, omin, omax;
@@ -356,22 +356,26 @@ static int clk_wzrd_get_divisors_ver(struct clk_hw *hw, unsigned long rate,
for (m = mmin; m <= mmax; m++) {
for (d = dmin; d <= dmax; d++) {
vco_freq = DIV_ROUND_CLOSEST((parent_rate * m), d);
if (vco_freq >= vcomin && vco_freq <= vcomax) {
for (o = omin; o <= omax; o++) {
freq = DIV_ROUND_CLOSEST_ULL(vco_freq, o);
diff = abs(freq - rate);
if (vco_freq < vcomin || vco_freq > vcomax)
continue;
if (diff < WZRD_MIN_ERR) {
divider->m = m;
divider->d = d;
divider->o = o;
return 0;
}
}
o = DIV_ROUND_CLOSEST_ULL(vco_freq, rate);
if (o < omin || o > omax)
continue;
freq = DIV_ROUND_CLOSEST_ULL(vco_freq, o);
diff = abs(freq - rate);
if (diff < best_diff) {
best_diff = diff;
divider->m = m;
divider->d = d;
divider->o = o;
if (!diff)
return 0;
}
}
}
return -EBUSY;
return 0;
}
static int clk_wzrd_get_divisors(struct clk_hw *hw, unsigned long rate,