When finding the best rate for a NKM clock, consider rates that are
higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
set.
Accommodate ccu_mux_helper_determine_rate to this change.
Signed-off-by: Frank Oltmanns <[email protected]>
---
drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
2 files changed, 54 insertions(+), 17 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
index 1d557e323169..8594d6a4addd 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.c
+++ b/drivers/clk/sunxi-ng/ccu_mux.c
@@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
}
for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
- unsigned long tmp_rate, parent_rate;
+ unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
struct clk_hw *parent;
parent = clk_hw_get_parent_by_index(hw, i);
@@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
goto out;
}
- if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
- best_rate = tmp_rate;
- best_parent_rate = parent_rate;
- best_parent = parent;
+ if (common->features & CCU_FEATURE_CLOSEST_RATE) {
+ unsigned long tmp_diff = req->rate > tmp_rate ?
+ req->rate - tmp_rate :
+ tmp_rate - req->rate;
+
+ if (tmp_diff < best_diff) {
+ best_rate = tmp_rate;
+ best_parent_rate = parent_rate;
+ best_parent = parent;
+ best_diff = tmp_diff;
+ }
+ } else {
+ if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
+ best_rate = tmp_rate;
+ best_parent_rate = parent_rate;
+ best_parent = parent;
+ }
}
}
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index d83843e69c25..36d9e987e4d8 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -18,9 +18,11 @@ struct _ccu_nkm {
};
static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
- struct _ccu_nkm *nkm, struct clk_hw *phw)
+ struct _ccu_nkm *nkm, struct clk_hw *phw,
+ unsigned long features)
{
- unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
+ unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
+ unsigned long best_diff = ULONG_MAX;
unsigned long best_n = 0, best_k = 0, best_m = 0;
unsigned long _n, _k, _m;
@@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
unsigned long tmp_rate;
+ unsigned long tmp_diff;
tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
tmp_rate = tmp_parent * _n * _k / _m;
- if (tmp_rate > rate)
- continue;
- if ((rate - tmp_rate) < (rate - best_rate)) {
+ if (features & CCU_FEATURE_CLOSEST_RATE) {
+ tmp_diff = rate > tmp_rate ?
+ rate - tmp_rate :
+ tmp_rate - rate;
+ } else {
+ if (tmp_rate > rate)
+ continue;
+ tmp_diff = rate - tmp_diff;
+ }
+
+ if (tmp_diff < best_diff) {
best_rate = tmp_rate;
best_parent_rate = tmp_parent;
+ best_diff = tmp_diff;
best_n = _n;
best_k = _k;
best_m = _m;
@@ -56,9 +68,10 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
}
static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
- struct _ccu_nkm *nkm)
+ struct _ccu_nkm *nkm, unsigned long features)
{
unsigned long best_rate = 0;
+ unsigned long best_diff = ULONG_MAX;
unsigned long best_n = 0, best_k = 0, best_m = 0;
unsigned long _n, _k, _m;
@@ -66,13 +79,23 @@ static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
unsigned long tmp_rate;
+ unsigned long tmp_diff;
tmp_rate = parent * _n * _k / _m;
- if (tmp_rate > rate)
- continue;
- if ((rate - tmp_rate) < (rate - best_rate)) {
+ if (features & CCU_FEATURE_CLOSEST_RATE) {
+ tmp_diff = rate > tmp_rate ?
+ rate - tmp_rate :
+ tmp_rate - rate;
+ } else {
+ if (tmp_rate > rate)
+ continue;
+ tmp_diff = rate - tmp_diff;
+ }
+
+ if (tmp_diff < best_diff) {
best_rate = tmp_rate;
+ best_diff = tmp_diff;
best_n = _n;
best_k = _k;
best_m = _m;
@@ -164,9 +187,10 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
rate *= nkm->fixed_post_div;
if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
- rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
+ rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm, nkm->common.features);
else
- rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw);
+ rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw,
+ nkm->common.features);
if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nkm->fixed_post_div;
@@ -201,7 +225,7 @@ static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
_nkm.min_m = 1;
_nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
- ccu_nkm_find_best(&parent_rate, rate, &_nkm);
+ ccu_nkm_find_best(parent_rate, rate, &_nkm, nkm->common.features);
spin_lock_irqsave(nkm->common.lock, flags);
--
2.41.0
Hi Frank,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 6995e2de6891c724bfeb2db33d7b87775f913ad1]
url: https://github.com/intel-lab-lkp/linux/commits/Frank-Oltmanns/clk-sunxi-ng-nkm-consider-alternative-parent-rates-when-determining-rate/20230703-015726
base: 6995e2de6891c724bfeb2db33d7b87775f913ad1
patch link: https://lore.kernel.org/r/20230702-pll-mipi_set_rate_parent-v3-5-46dcb8aa9cbc%40oltmanns.dev
patch subject: [PATCH v3 5/8] clk: sunxi-ng: nkm: Support finding closest rate
config: riscv-rv32_defconfig (https://download.01.org/0day-ci/archive/20230703/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230703/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
>> drivers/clk/sunxi-ng/ccu_nkm.c:46:24: warning: variable 'tmp_diff' is uninitialized when used here [-Wuninitialized]
46 | tmp_diff = rate - tmp_diff;
| ^~~~~~~~
drivers/clk/sunxi-ng/ccu_nkm.c:33:27: note: initialize the variable 'tmp_diff' to silence this warning
33 | unsigned long tmp_diff;
| ^
| = 0
drivers/clk/sunxi-ng/ccu_nkm.c:93:24: warning: variable 'tmp_diff' is uninitialized when used here [-Wuninitialized]
93 | tmp_diff = rate - tmp_diff;
| ^~~~~~~~
drivers/clk/sunxi-ng/ccu_nkm.c:82:27: note: initialize the variable 'tmp_diff' to silence this warning
82 | unsigned long tmp_diff;
| ^
| = 0
2 warnings generated.
vim +/tmp_diff +46 drivers/clk/sunxi-ng/ccu_nkm.c
19
20 static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
21 struct _ccu_nkm *nkm, struct clk_hw *phw,
22 unsigned long features)
23 {
24 unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
25 unsigned long best_diff = ULONG_MAX;
26 unsigned long best_n = 0, best_k = 0, best_m = 0;
27 unsigned long _n, _k, _m;
28
29 for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
30 for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
31 for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
32 unsigned long tmp_rate;
33 unsigned long tmp_diff;
34
35 tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
36
37 tmp_rate = tmp_parent * _n * _k / _m;
38
39 if (features & CCU_FEATURE_CLOSEST_RATE) {
40 tmp_diff = rate > tmp_rate ?
41 rate - tmp_rate :
42 tmp_rate - rate;
43 } else {
44 if (tmp_rate > rate)
45 continue;
> 46 tmp_diff = rate - tmp_diff;
47 }
48
49 if (tmp_diff < best_diff) {
50 best_rate = tmp_rate;
51 best_parent_rate = tmp_parent;
52 best_diff = tmp_diff;
53 best_n = _n;
54 best_k = _k;
55 best_m = _m;
56 }
57 }
58 }
59 }
60
61 nkm->n = best_n;
62 nkm->k = best_k;
63 nkm->m = best_m;
64
65 *parent = best_parent_rate;
66
67 return best_rate;
68 }
69
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On 2023-07-02 at 19:55:24 +0200, Frank Oltmanns <[email protected]> wrote:
> When finding the best rate for a NKM clock, consider rates that are
> higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
> set.
>
> Accommodate ccu_mux_helper_determine_rate to this change.
>
> Signed-off-by: Frank Oltmanns <[email protected]>
> ---
> drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
> drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
> 2 files changed, 54 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 1d557e323169..8594d6a4addd 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> }
>
> for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> - unsigned long tmp_rate, parent_rate;
> + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
> struct clk_hw *parent;
>
> parent = clk_hw_get_parent_by_index(hw, i);
> @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> goto out;
> }
>
> - if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> - best_rate = tmp_rate;
> - best_parent_rate = parent_rate;
> - best_parent = parent;
> + if (common->features & CCU_FEATURE_CLOSEST_RATE) {
> + unsigned long tmp_diff = req->rate > tmp_rate ?
> + req->rate - tmp_rate :
> + tmp_rate - req->rate;
> +
> + if (tmp_diff < best_diff) {
> + best_rate = tmp_rate;
> + best_parent_rate = parent_rate;
> + best_parent = parent;
> + best_diff = tmp_diff;
> + }
> + } else {
> + if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> + best_rate = tmp_rate;
> + best_parent_rate = parent_rate;
> + best_parent = parent;
> + }
> }
> }
>
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index d83843e69c25..36d9e987e4d8 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -18,9 +18,11 @@ struct _ccu_nkm {
> };
>
> static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
> - struct _ccu_nkm *nkm, struct clk_hw *phw)
> + struct _ccu_nkm *nkm, struct clk_hw *phw,
> + unsigned long features)
> {
> - unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
> + unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
> + unsigned long best_diff = ULONG_MAX;
> unsigned long best_n = 0, best_k = 0, best_m = 0;
> unsigned long _n, _k, _m;
>
> @@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
> for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
> for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
> unsigned long tmp_rate;
> + unsigned long tmp_diff;
>
> tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
>
> tmp_rate = tmp_parent * _n * _k / _m;
> - if (tmp_rate > rate)
> - continue;
>
> - if ((rate - tmp_rate) < (rate - best_rate)) {
> + if (features & CCU_FEATURE_CLOSEST_RATE) {
> + tmp_diff = rate > tmp_rate ?
> + rate - tmp_rate :
> + tmp_rate - rate;
> + } else {
> + if (tmp_rate > rate)
> + continue;
> + tmp_diff = rate - tmp_diff;
Sorry, this should of course be tmp_diff = rate - tmp_rate. I'll fix
that in v4. Also I'll do tests on my phone where
CCU_FEATURE_CLOSEST_RATE is not set (i.e., without PATCH 8), so see if
it replicates the old behaviour. I'll also look into adding kunit tests,
so that this doesn't happen again. I'm not sure if this is feasible, but
I'll ask here for advise, if/when I encounter obstacles.
Best regards,
Frank
> + }
> +
> + if (tmp_diff < best_diff) {
> best_rate = tmp_rate;
> best_parent_rate = tmp_parent;
> + best_diff = tmp_diff;
> best_n = _n;
> best_k = _k;
> best_m = _m;
> @@ -56,9 +68,10 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
> }
>
> static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
> - struct _ccu_nkm *nkm)
> + struct _ccu_nkm *nkm, unsigned long features)
> {
> unsigned long best_rate = 0;
> + unsigned long best_diff = ULONG_MAX;
> unsigned long best_n = 0, best_k = 0, best_m = 0;
> unsigned long _n, _k, _m;
>
> @@ -66,13 +79,23 @@ static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
> for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
> for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
> unsigned long tmp_rate;
> + unsigned long tmp_diff;
>
> tmp_rate = parent * _n * _k / _m;
>
> - if (tmp_rate > rate)
> - continue;
> - if ((rate - tmp_rate) < (rate - best_rate)) {
> + if (features & CCU_FEATURE_CLOSEST_RATE) {
> + tmp_diff = rate > tmp_rate ?
> + rate - tmp_rate :
> + tmp_rate - rate;
> + } else {
> + if (tmp_rate > rate)
> + continue;
> + tmp_diff = rate - tmp_diff;
> + }
> +
> + if (tmp_diff < best_diff) {
> best_rate = tmp_rate;
> + best_diff = tmp_diff;
> best_n = _n;
> best_k = _k;
> best_m = _m;
> @@ -164,9 +187,10 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
> rate *= nkm->fixed_post_div;
>
> if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
> - rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
> + rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm, nkm->common.features);
> else
> - rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw);
> + rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw,
> + nkm->common.features);
>
> if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
> rate /= nkm->fixed_post_div;
> @@ -201,7 +225,7 @@ static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
> _nkm.min_m = 1;
> _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
>
> - ccu_nkm_find_best(&parent_rate, rate, &_nkm);
> + ccu_nkm_find_best(parent_rate, rate, &_nkm, nkm->common.features);
>
> spin_lock_irqsave(nkm->common.lock, flags);
On Sun, Jul 02, 2023 at 07:55:24PM +0200, Frank Oltmanns wrote:
> When finding the best rate for a NKM clock, consider rates that are
> higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
> set.
>
> Accommodate ccu_mux_helper_determine_rate to this change.
>
> Signed-off-by: Frank Oltmanns <[email protected]>
> ---
> drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
> drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
> 2 files changed, 54 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 1d557e323169..8594d6a4addd 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> }
>
> for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> - unsigned long tmp_rate, parent_rate;
> + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
> struct clk_hw *parent;
>
> parent = clk_hw_get_parent_by_index(hw, i);
> @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> goto out;
> }
>
> - if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> - best_rate = tmp_rate;
> - best_parent_rate = parent_rate;
> - best_parent = parent;
> + if (common->features & CCU_FEATURE_CLOSEST_RATE) {
> + unsigned long tmp_diff = req->rate > tmp_rate ?
> + req->rate - tmp_rate :
> + tmp_rate - req->rate;
> +
> + if (tmp_diff < best_diff) {
> + best_rate = tmp_rate;
> + best_parent_rate = parent_rate;
> + best_parent = parent;
> + best_diff = tmp_diff;
> + }
> + } else {
> + if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> + best_rate = tmp_rate;
> + best_parent_rate = parent_rate;
> + best_parent = parent;
> + }
> }
> }
Like I said in the previous patch, I think we could do something like:
bool ccu_is_better_rate(struct ccu_common *common,
unsigned long target_rate,
unsigned long current_rate,
unsigned long best_rate)
{
if (common->features & CCU_FEATURE_CLOSEST_RATE)
return abs(current_rate - target_rate) < abs(best_rate - target_rate);
return current_rate <= target_rate && current_rate > best_rate;
}
Then, the code above would look like:
if (ccu_is_better_rate(common, req->rate, tmp_rate, best_rate)) {
best_rate = tmp_rate;
best_parent_rate = parent_rate;
best_parent = parent;
}
It's simpler, and we can share it easily between drivers.
Maxime
On Mon, Jul 03, 2023 at 09:17:43AM +0200, Frank Oltmanns wrote:
>
> On 2023-07-02 at 19:55:24 +0200, Frank Oltmanns <[email protected]> wrote:
> > When finding the best rate for a NKM clock, consider rates that are
> > higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
> > set.
> >
> > Accommodate ccu_mux_helper_determine_rate to this change.
> >
> > Signed-off-by: Frank Oltmanns <[email protected]>
> > ---
> > drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
> > drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
> > 2 files changed, 54 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> > index 1d557e323169..8594d6a4addd 100644
> > --- a/drivers/clk/sunxi-ng/ccu_mux.c
> > +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> > @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> > }
> >
> > for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> > - unsigned long tmp_rate, parent_rate;
> > + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
> > struct clk_hw *parent;
> >
> > parent = clk_hw_get_parent_by_index(hw, i);
> > @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> > goto out;
> > }
> >
> > - if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> > - best_rate = tmp_rate;
> > - best_parent_rate = parent_rate;
> > - best_parent = parent;
> > + if (common->features & CCU_FEATURE_CLOSEST_RATE) {
> > + unsigned long tmp_diff = req->rate > tmp_rate ?
> > + req->rate - tmp_rate :
> > + tmp_rate - req->rate;
> > +
> > + if (tmp_diff < best_diff) {
> > + best_rate = tmp_rate;
> > + best_parent_rate = parent_rate;
> > + best_parent = parent;
> > + best_diff = tmp_diff;
> > + }
> > + } else {
> > + if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> > + best_rate = tmp_rate;
> > + best_parent_rate = parent_rate;
> > + best_parent = parent;
> > + }
> > }
> > }
> >
> > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> > index d83843e69c25..36d9e987e4d8 100644
> > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> > @@ -18,9 +18,11 @@ struct _ccu_nkm {
> > };
> >
> > static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
> > - struct _ccu_nkm *nkm, struct clk_hw *phw)
> > + struct _ccu_nkm *nkm, struct clk_hw *phw,
> > + unsigned long features)
> > {
> > - unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
> > + unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
> > + unsigned long best_diff = ULONG_MAX;
> > unsigned long best_n = 0, best_k = 0, best_m = 0;
> > unsigned long _n, _k, _m;
> >
> > @@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
> > for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
> > for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
> > unsigned long tmp_rate;
> > + unsigned long tmp_diff;
> >
> > tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
> >
> > tmp_rate = tmp_parent * _n * _k / _m;
> > - if (tmp_rate > rate)
> > - continue;
> >
> > - if ((rate - tmp_rate) < (rate - best_rate)) {
> > + if (features & CCU_FEATURE_CLOSEST_RATE) {
> > + tmp_diff = rate > tmp_rate ?
> > + rate - tmp_rate :
> > + tmp_rate - rate;
> > + } else {
> > + if (tmp_rate > rate)
> > + continue;
> > + tmp_diff = rate - tmp_diff;
>
> Sorry, this should of course be tmp_diff = rate - tmp_rate. I'll fix
> that in v4. Also I'll do tests on my phone where
> CCU_FEATURE_CLOSEST_RATE is not set (i.e., without PATCH 8), so see if
> it replicates the old behaviour. I'll also look into adding kunit tests,
> so that this doesn't happen again. I'm not sure if this is feasible, but
> I'll ask here for advise, if/when I encounter obstacles.
While this would obviously be great, I don't think we have the
infrastructure just yet to allow to easily add kunit tests for entire
clocks.
Maxime
On 2023-07-03 at 09:25:59 +0200, Maxime Ripard <[email protected]> wrote:
> [[PGP Signed Part:Undecided]]
> On Mon, Jul 03, 2023 at 09:17:43AM +0200, Frank Oltmanns wrote:
>>
>> On 2023-07-02 at 19:55:24 +0200, Frank Oltmanns <[email protected]> wrote:
>> > When finding the best rate for a NKM clock, consider rates that are
>> > higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
>> > set.
>> >
>> > Accommodate ccu_mux_helper_determine_rate to this change.
>> >
>> > Signed-off-by: Frank Oltmanns <[email protected]>
>> > ---
>> > drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
>> > drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
>> > 2 files changed, 54 insertions(+), 17 deletions(-)
>> >
>> > diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
>> > index 1d557e323169..8594d6a4addd 100644
>> > --- a/drivers/clk/sunxi-ng/ccu_mux.c
>> > +++ b/drivers/clk/sunxi-ng/ccu_mux.c
>> > @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>> > }
>> >
>> > for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
>> > - unsigned long tmp_rate, parent_rate;
>> > + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
>> > struct clk_hw *parent;
>> >
>> > parent = clk_hw_get_parent_by_index(hw, i);
>> > @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>> > goto out;
>> > }
>> >
>> > - if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
>> > - best_rate = tmp_rate;
>> > - best_parent_rate = parent_rate;
>> > - best_parent = parent;
>> > + if (common->features & CCU_FEATURE_CLOSEST_RATE) {
>> > + unsigned long tmp_diff = req->rate > tmp_rate ?
>> > + req->rate - tmp_rate :
>> > + tmp_rate - req->rate;
>> > +
>> > + if (tmp_diff < best_diff) {
>> > + best_rate = tmp_rate;
>> > + best_parent_rate = parent_rate;
>> > + best_parent = parent;
>> > + best_diff = tmp_diff;
>> > + }
>> > + } else {
>> > + if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
>> > + best_rate = tmp_rate;
>> > + best_parent_rate = parent_rate;
>> > + best_parent = parent;
>> > + }
>> > }
>> > }
>> >
>> > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
>> > index d83843e69c25..36d9e987e4d8 100644
>> > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
>> > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
>> > @@ -18,9 +18,11 @@ struct _ccu_nkm {
>> > };
>> >
>> > static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
>> > - struct _ccu_nkm *nkm, struct clk_hw *phw)
>> > + struct _ccu_nkm *nkm, struct clk_hw *phw,
>> > + unsigned long features)
>> > {
>> > - unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
>> > + unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
>> > + unsigned long best_diff = ULONG_MAX;
>> > unsigned long best_n = 0, best_k = 0, best_m = 0;
>> > unsigned long _n, _k, _m;
>> >
>> > @@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
>> > for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
>> > for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
>> > unsigned long tmp_rate;
>> > + unsigned long tmp_diff;
>> >
>> > tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
>> >
>> > tmp_rate = tmp_parent * _n * _k / _m;
>> > - if (tmp_rate > rate)
>> > - continue;
>> >
>> > - if ((rate - tmp_rate) < (rate - best_rate)) {
>> > + if (features & CCU_FEATURE_CLOSEST_RATE) {
>> > + tmp_diff = rate > tmp_rate ?
>> > + rate - tmp_rate :
>> > + tmp_rate - rate;
>> > + } else {
>> > + if (tmp_rate > rate)
>> > + continue;
>> > + tmp_diff = rate - tmp_diff;
>>
>> Sorry, this should of course be tmp_diff = rate - tmp_rate. I'll fix
>> that in v4. Also I'll do tests on my phone where
>> CCU_FEATURE_CLOSEST_RATE is not set (i.e., without PATCH 8), so see if
>> it replicates the old behaviour. I'll also look into adding kunit tests,
>> so that this doesn't happen again. I'm not sure if this is feasible, but
>> I'll ask here for advise, if/when I encounter obstacles.
>
> While this would obviously be great, I don't think we have the
> infrastructure just yet to allow to easily add kunit tests for entire
> clocks.
I think, clk_test.c provides a good blueprint. I tried to do that for
clk-fractional-divider [1], but Stephen wanted to go a different route,
so I dropped it. You could look at clk_fd_test_init() in [1]. A similar
approach might work for the sunxi-ng clocks. I don't see any real
blockers, but maybe that's me being naive.
[1]: https://lore.kernel.org/all/[email protected]/
Best regards,
Frank
>
> Maxime
>
> [[End of PGP Signed Part]]
On Mon, Jul 03, 2023 at 10:59:43AM +0200, Frank Oltmanns wrote:
>
> On 2023-07-03 at 09:25:59 +0200, Maxime Ripard <[email protected]> wrote:
> > [[PGP Signed Part:Undecided]]
> > On Mon, Jul 03, 2023 at 09:17:43AM +0200, Frank Oltmanns wrote:
> >>
> >> On 2023-07-02 at 19:55:24 +0200, Frank Oltmanns <[email protected]> wrote:
> >> > When finding the best rate for a NKM clock, consider rates that are
> >> > higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
> >> > set.
> >> >
> >> > Accommodate ccu_mux_helper_determine_rate to this change.
> >> >
> >> > Signed-off-by: Frank Oltmanns <[email protected]>
> >> > ---
> >> > drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
> >> > drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
> >> > 2 files changed, 54 insertions(+), 17 deletions(-)
> >> >
> >> > diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> >> > index 1d557e323169..8594d6a4addd 100644
> >> > --- a/drivers/clk/sunxi-ng/ccu_mux.c
> >> > +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> >> > @@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> >> > }
> >> >
> >> > for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
> >> > - unsigned long tmp_rate, parent_rate;
> >> > + unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
> >> > struct clk_hw *parent;
> >> >
> >> > parent = clk_hw_get_parent_by_index(hw, i);
> >> > @@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
> >> > goto out;
> >> > }
> >> >
> >> > - if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> >> > - best_rate = tmp_rate;
> >> > - best_parent_rate = parent_rate;
> >> > - best_parent = parent;
> >> > + if (common->features & CCU_FEATURE_CLOSEST_RATE) {
> >> > + unsigned long tmp_diff = req->rate > tmp_rate ?
> >> > + req->rate - tmp_rate :
> >> > + tmp_rate - req->rate;
> >> > +
> >> > + if (tmp_diff < best_diff) {
> >> > + best_rate = tmp_rate;
> >> > + best_parent_rate = parent_rate;
> >> > + best_parent = parent;
> >> > + best_diff = tmp_diff;
> >> > + }
> >> > + } else {
> >> > + if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> >> > + best_rate = tmp_rate;
> >> > + best_parent_rate = parent_rate;
> >> > + best_parent = parent;
> >> > + }
> >> > }
> >> > }
> >> >
> >> > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> >> > index d83843e69c25..36d9e987e4d8 100644
> >> > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> >> > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> >> > @@ -18,9 +18,11 @@ struct _ccu_nkm {
> >> > };
> >> >
> >> > static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
> >> > - struct _ccu_nkm *nkm, struct clk_hw *phw)
> >> > + struct _ccu_nkm *nkm, struct clk_hw *phw,
> >> > + unsigned long features)
> >> > {
> >> > - unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
> >> > + unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
> >> > + unsigned long best_diff = ULONG_MAX;
> >> > unsigned long best_n = 0, best_k = 0, best_m = 0;
> >> > unsigned long _n, _k, _m;
> >> >
> >> > @@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
> >> > for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
> >> > for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
> >> > unsigned long tmp_rate;
> >> > + unsigned long tmp_diff;
> >> >
> >> > tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
> >> >
> >> > tmp_rate = tmp_parent * _n * _k / _m;
> >> > - if (tmp_rate > rate)
> >> > - continue;
> >> >
> >> > - if ((rate - tmp_rate) < (rate - best_rate)) {
> >> > + if (features & CCU_FEATURE_CLOSEST_RATE) {
> >> > + tmp_diff = rate > tmp_rate ?
> >> > + rate - tmp_rate :
> >> > + tmp_rate - rate;
> >> > + } else {
> >> > + if (tmp_rate > rate)
> >> > + continue;
> >> > + tmp_diff = rate - tmp_diff;
> >>
> >> Sorry, this should of course be tmp_diff = rate - tmp_rate. I'll fix
> >> that in v4. Also I'll do tests on my phone where
> >> CCU_FEATURE_CLOSEST_RATE is not set (i.e., without PATCH 8), so see if
> >> it replicates the old behaviour. I'll also look into adding kunit tests,
> >> so that this doesn't happen again. I'm not sure if this is feasible, but
> >> I'll ask here for advise, if/when I encounter obstacles.
> >
> > While this would obviously be great, I don't think we have the
> > infrastructure just yet to allow to easily add kunit tests for entire
> > clocks.
>
> I think, clk_test.c provides a good blueprint. I tried to do that for
> clk-fractional-divider [1], but Stephen wanted to go a different route,
> so I dropped it. You could look at clk_fd_test_init() in [1]. A similar
> approach might work for the sunxi-ng clocks. I don't see any real
> blockers, but maybe that's me being naive.
The main issue will be probing and mocking. Those clocks are meant to be
probed through the device tree and expect to have underlying registers
accessible.
We would need some way to mock / prevent any register access, while
still registering a clock with its device tree node, parent, etc. for
the tests to be meaningful. And that's not going to be an easy thing to
do :)
Maxime