Unverified Commit e0a94c6b authored by Shubhrajyoti Datta's avatar Shubhrajyoti Datta Committed by Stephen Boyd
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clk: xilinx: Optimize divisor search in clk_wzrd_get_divisors_ver() 



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: default avatarShubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 8f5ae30d

drivers/clk/xilinx/clk-xlnx-clock-wizard.c

+18 −14
Original line number Diff line number Diff line
@@ -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++) {

			if (vco_freq < vcomin || vco_freq > vcomax)

				continue;



			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 < WZRD_MIN_ERR) {

			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,