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k210: clk: Refactor out_of_spec tests

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Everything here sits in a while (true) loop. However, this introduces a
couple of layers of indentation. We can simplify the code by introducing a
single goto instead of using continue/break. This will also make adding
loops in the next patch easier.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
This commit is contained in:
Sean Anderson 2021-09-11 13:20:01 -04:00 • committed by Leo Yu-Chi Liang
parent 54d5d2d56b
commit 4970874970
1 changed files with 52 additions and 53 deletions
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105
drivers/clk/clk_kendryte.c
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@ -709,6 +709,10 @@ TEST_STATIC int k210_pll_calc_config(u32 rate, u32 rate_in,
* Whether we swapped r and od while enforcing frequency limits
*/
bool swapped = false;
/*
* Whether the intermediate frequencies are out-of-spec
*/
bool out_of_spec;
u64 last_od = od;
u64 last_r = r;
@ -767,76 +771,71 @@ TEST_STATIC int k210_pll_calc_config(u32 rate, u32 rate_in,
* aren't in spec, try swapping r and od. If everything is
* in-spec, calculate the relative error.
*/
while (true) {
again:
out_of_spec = false;
if (r > max_r) {
out_of_spec = true;
} else {
/*
* Whether the intermediate frequencies are out-of-spec
* There is no way to only divide once; we need
* to examine the frequency with and without the
* effect of od.
*/
bool out_of_spec = false;
u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
if (r > max_r) {
if (vco > 1750000000 || vco < 340000000)
out_of_spec = true;
} else {
/*
* There is no way to only divide once; we need
* to examine the frequency with and without the
* effect of od.
*/
u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
}
if (vco > 1750000000 || vco < 340000000)
out_of_spec = true;
if (out_of_spec) {
u64 new_r, new_od;
if (!swapped) {
u64 tmp = r;
r = od;
od = tmp;
swapped = true;
goto again;
}
if (out_of_spec) {
if (!swapped) {
u64 tmp = r;
r = od;
od = tmp;
swapped = true;
continue;
} else {
/*
* Try looking ahead to see if there are
* additional factors for the same
* product.
*/
if (i + 1 < ARRAY_SIZE(factors)) {
u64 new_r, new_od;
i++;
new_r = UNPACK_R(factors[i]);
new_od = UNPACK_OD(factors[i]);
if (r * od == new_r * new_od) {
r = new_r;
od = new_od;
swapped = false;
continue;
}
i--;
}
break;
/*
* Try looking ahead to see if there are additional
* factors for the same product.
*/
if (i + 1 < ARRAY_SIZE(factors)) {
i++;
new_r = UNPACK_R(factors[i]);
new_od = UNPACK_OD(factors[i]);
if (r * od == new_r * new_od) {
r = new_r;
od = new_od;
swapped = false;
goto again;
}
i--;
}
error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio, r * od);
/* The lower 16 bits are spurious */
error = abs((error - BIT(32))) >> 16;
/* We ran out of things to try */
continue;
}
if (error < best_error) {
best->r = r;
best->f = f;
best->od = od;
best_error = error;
}
break;
error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio, r * od);
/* The lower 16 bits are spurious */
error = abs((error - BIT(32))) >> 16;
if (error < best_error) {
best->r = r;
best->f = f;
best->od = od;
best_error = error;
}
} while (f < 64 && i + 1 < ARRAY_SIZE(factors) && error != 0);
log_debug("best error %lld\n", best_error);
if (best_error == S64_MAX)
return -EINVAL;
log_debug("best error %lld\n", best_error);
return 0;
}