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

["Jernej Škrabec" <jernej.skrabec@siol.net>]

Dne sreda, 16. januar 2019 ob 13:09:58 CET je Priit Laes napisal(a):
> On Thu, Jan 10, 2019 at 06:10:59PM +0100, Jernej Škrabec wrote:
> > 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?
> 
> In both cases I booted from FEL with rootfs on sdcard and tried to mount
> partition from eMMC to /mnt. With your patch, last step it fails.
> 
> pre-patch working:
> pll-ddr-other[768MHz] -> mmc2[512MHz]. (For some reason ahb-mmc2 is off?)
> 
> post-patch not working:
> pll-periph[600MHz] ->  mmc2[500Mhz], (ahb-mmc2 is enabled)
> 
> Also, attached the logs.

Thanks. Just one more request. Can you enable debug messages in mmc driver? 
I'm interested in output of this line:

dev_dbg(mmc_dev(mmc), "setting clk to %d, rounded %ld\n",
		clock, rate);

Just wondering what it should be.

Best regards,
Jernej

> 
> > 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@siol.net>
> > > > ---
> > > > 
> > > >  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;