From: Sean Anderson <seanga2@gmail.com>
To: u-boot@lists.denx.de, Leo Liang <ycliang@andestech.com>
Cc: Bin Meng <bmeng.cn@gmail.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Lukasz Majewski <lukma@denx.de>,
Sean Anderson <seanga2@gmail.com>
Subject: [PATCH v2 2/4] k210: clk: Refactor out_of_spec tests
Date: Sat, 11 Sep 2021 13:20:01 -0400 [thread overview]
Message-ID: <20210911172003.899301-2-seanga2@gmail.com> (raw)
In-Reply-To: <20210911172003.899301-1-seanga2@gmail.com>
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>
---
(no changes since v1)
drivers/clk/clk_kendryte.c | 105 ++++++++++++++++++-------------------
1 file changed, 52 insertions(+), 53 deletions(-)
diff --git a/drivers/clk/clk_kendryte.c b/drivers/clk/clk_kendryte.c
index 2caa21aec9..69691c4a04 100644
--- a/drivers/clk/clk_kendryte.c
+++ b/drivers/clk/clk_kendryte.c
@@ -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;
}
--
2.33.0
next prev parent reply other threads:[~2021-09-11 17:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 17:20 [PATCH v2 1/4] clk: k210: Fix checking if ulongs are less than 0 Sean Anderson
2021-09-11 17:20 ` Sean Anderson [this message]
2021-09-14 8:45 ` [PATCH v2 2/4] k210: clk: Refactor out_of_spec tests Leo Liang
2021-09-11 17:20 ` [PATCH v2 3/4] test: dm: k210: Reduce duplication in test cases Sean Anderson
2021-09-14 8:48 ` Leo Liang
2021-09-11 17:20 ` [PATCH v2 4/4] clk: k210: Try harder to get the best config Sean Anderson
2021-09-30 4:08 ` Simon Glass
2021-09-14 8:39 ` [PATCH v2 1/4] clk: k210: Fix checking if ulongs are less than 0 Leo Liang
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