Re: [PATCH v3 02/28] clk: sunxi-ng: Adjust MP clock parent rate when allowed

Jernej Škrabec
2019-01-10T17:10:59Z

Dne četrtek, 10. januar 2019 ob 10:15:48 CET je Priit Laes napisal(a):
> On Sun, Nov 04, 2018 at 07:26:39PM +0100, Jernej Skrabec wrote:
> > Currently MP clocks don't consider adjusting parent rate even if they
> > are allowed to do so. Such behaviour considerably lowers amount of
> > possible rates, which is very inconvenient when such clock is used for
> > pixel clock, for example.
> >
> > In order to improve the situation, adjusting parent rate is considered
> > when allowed.
> >
> > This code is inspired by clk_divider_bestdiv() function, which does
> > basically the same thing for different clock type.
>
> This patch seems to break the eMMC support on Olinuxino-Lime2-eMMC boards:
>
> EXT4-fs (mmcblk1p4): INFO: recovery required on readonly filesystem
> EXT4-fs (mmcblk1p4): write access will be enabled during recovery
> sunxi-mmc 1c11000.mmc: data error, sending stop command
> sunxi-mmc 1c11000.mmc: send stop command failed
>

I'm not familiar with A20. What is interesting is that emmc clocks don't have
CLK_SET_RATE_PARENT flag set, so you shouldn't see any difference.

Can you post content of clk_summary with and without this patch?

Best regards,
Jernej

>
> $ git bisect log
> git bisect start
> # good: [3df407b2a5346db1c48809706ece7a8616c79e0b] mmc: dw_mmc-bluefield:
> simplify the probe() function git bisect good
> 3df407b2a5346db1c48809706ece7a8616c79e0b
> # bad: [00d59fde8532b2d42e80909d2e58678755e04da9] Merge tag 'mmc-v4.21' of
> git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc git bisect bad
> 00d59fde8532b2d42e80909d2e58678755e04da9
> # good: [01e421feec0817bb3141eaae4c517410d193d440] Merge branch 'fixes' into
> next git bisect good 01e421feec0817bb3141eaae4c517410d193d440
> # bad: [1eefdec18eded41833401cfd64749643ff72e7da] Merge branch
> 'locking-core-for-linus' of
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect bad
> 1eefdec18eded41833401cfd64749643ff72e7da
> # good: [eaa76499711535fd64d747cc4ef0d78ab0fd41c6] Merge tag 'mtd/for-4.21'
> of git://git.infradead.org/linux-mtd git bisect good
> eaa76499711535fd64d747cc4ef0d78ab0fd41c6
> # good: [4e4390ad067a61ce4e7607bd0df31f19a4caa36a] Merge tag
> 'leds-for-4.21-rc1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds git
> bisect good 4e4390ad067a61ce4e7607bd0df31f19a4caa36a
> # bad: [c2f1f3e0e17d94ab0c66d83e669492cb9e9a3698] Merge
> git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next git bisect
> bad c2f1f3e0e17d94ab0c66d83e669492cb9e9a3698
> # bad: [e4b99d415c3908581d4703203e1e805f043a3e71] Merge branch
> 'irq-core-for-linus' of
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect bad
> e4b99d415c3908581d4703203e1e805f043a3e71
> # bad: [ffe05540d18013db62c43627836a3638e9a2c7aa] Merge branches
> 'clk-renesas', 'clk-allwinner', 'clk-tegra', 'clk-meson' and 'clk-rockchip'
> into clk-next git bisect bad ffe05540d18013db62c43627836a3638e9a2c7aa
> # good: [1a501c8defe950571316d5ddd917bf44f5ed7bd4] Merge branches
> 'clk-managed-registration', 'clk-spdx', 'clk-remove-basic' and
> 'clk-ops-const' into clk-next git bisect good
> 1a501c8defe950571316d5ddd917bf44f5ed7bd4
> # good: [e74581b79ddd9b49b8c61e2791fc4dffc0245afb] Merge tag
> 'meson-clk-4.21-2' of https://github.com/BayLibre/clk-meson into clk-meson
> git bisect good e74581b79ddd9b49b8c61e2791fc4dffc0245afb
> # good: [60baf75e3f5b76043c25328ac0c5320aaef5ea41] Merge tag
> 'clk-renesas-for-v4.21-tag2' of
> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers into
> clk-renesas git bisect good 60baf75e3f5b76043c25328ac0c5320aaef5ea41
> # bad: [a41f85b6017ee20952a60e4330bcae2527fe2c2a] Merge tag
> 'sunxi-clk-for-4.21' of
> https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux into
> clk-allwinner git bisect bad a41f85b6017ee20952a60e4330bcae2527fe2c2a
> # bad: [ee678706e46d0d185c27cc214ad97828e0643159] clk: sunxi-ng: a64: Fix
> gate bit of DSI DPHY git bisect bad
> ee678706e46d0d185c27cc214ad97828e0643159
> # bad: [65b6657672388b72822e0367f06d41c1e3ffb5bb] clk: sunxi-ng: Use u64 for
> calculation of NM rate git bisect bad
> 65b6657672388b72822e0367f06d41c1e3ffb5bb
> # good: [db7548934603d9eda12649dff97ea5c29884405d] clk: sunxi-ng: sun50i:
> h6: Fix MMC clock mux width git bisect good
> db7548934603d9eda12649dff97ea5c29884405d
> # bad: [3f790433c3cb27ecaf2ca0e07ac25964e4fd9f15] clk: sunxi-ng: Adjust MP
> clock parent rate when allowed git bisect bad
> 3f790433c3cb27ecaf2ca0e07ac25964e4fd9f15
> # first bad commit: [3f790433c3cb27ecaf2ca0e07ac25964e4fd9f15] clk:
> sunxi-ng: Adjust MP clock parent rate when allowed
> > Signed-off-by: Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org>
> > ---
> >
> > drivers/clk/sunxi-ng/ccu_mp.c | 64 +++++++++++++++++++++++++++++++++--
> > 1 file changed, 62 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/clk/sunxi-ng/ccu_mp.c b/drivers/clk/sunxi-ng/ccu_mp.c
> > index 5d0af4051737..0357349eb767 100644
> > --- a/drivers/clk/sunxi-ng/ccu_mp.c
> > +++ b/drivers/clk/sunxi-ng/ccu_mp.c
> > @@ -40,6 +40,61 @@ static void ccu_mp_find_best(unsigned long parent,
> > unsigned long rate,>
> > *p = best_p;
> >
> > }
> >
> > +static unsigned long ccu_mp_find_best_with_parent_adj(struct clk_hw *hw,
> > +
unsigned long *parent,
> > +
unsigned long rate,
> > +
unsigned int max_m,
> > +
unsigned int max_p)
> > +{
> > + unsigned long parent_rate_saved;
> > + unsigned long parent_rate, now;
> > + unsigned long best_rate = 0;
> > + unsigned int _m, _p, div;
> > + unsigned long maxdiv;
> > +
> > + parent_rate_saved = *parent;
> > +
> > + /*
> > + * The maximum divider we can use without overflowing
> > + * unsigned long in rate * m * p below
> > + */
> > + maxdiv = max_m * max_p;
> > + maxdiv = min(ULONG_MAX / rate, maxdiv);
> > +
> > + for (_p = 1; _p <= max_p; _p <<= 1) {
> > + for (_m = 1; _m <= max_m; _m++) {
> > + div = _m * _p;
> > +
> > + if (div > maxdiv)
> > + break;
> > +
> > + if (rate * div == parent_rate_saved) {
> > + /*
> > + * It's the most ideal case if
the requested
> > + * rate can be divided from
parent clock without
> > + * needing to change parent rate,
so return the
> > + * divider immediately.
> > + */
> > + *parent = parent_rate_saved;
> > + return rate;
> > + }
> > +
> > + parent_rate = clk_hw_round_rate(hw, rate *
div);
> > + now = parent_rate / div;
> > +
> > + if (now <= rate && now > best_rate) {
> > + best_rate = now;
> > + *parent = parent_rate;
> > +
> > + if (now == rate)
> > + return rate;
> > + }
> > + }
> > + }
> > +
> > + return best_rate;
> > +}
> > +
> >
> > static unsigned long ccu_mp_round_rate(struct ccu_mux_internal *mux,
> >
> > struct clk_hw *hw,
> > unsigned long
*parent_rate,
> >
> > @@ -56,8 +111,13 @@ static unsigned long ccu_mp_round_rate(struct
> > ccu_mux_internal *mux,>
> > max_m = cmp->m.max ?: 1 << cmp->m.width;
> > max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1);
> >
> > - ccu_mp_find_best(*parent_rate, rate, max_m, max_p, &m, &p);
> > - rate = *parent_rate / p / m;
> > + if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
> > + ccu_mp_find_best(*parent_rate, rate, max_m, max_p, &m,
&p);
> > + rate = *parent_rate / p / m;
> > + } else {
> > + rate = ccu_mp_find_best_with_parent_adj(hw, parent_rate,
rate,
> > +
max_m, max_p);
> > + }
> >
> > if (cmp->common.features & CCU_FEATURE_FIXED_POSTDIV)
> >
> > rate /= cmp->fixed_post_div;

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