Date:	Wed, 17 Dec 2014 13:11:05 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:	Magnus Damm <magnus.damm@...il.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	SH-Linux <linux-sh@...r.kernel.org>,
	"Simon Horman [Horms]" <horms@...ge.net.au>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] clocksource: sh_tmu: Set cpu_possible_mask to fix SMP broadcast

Hi Laurent,

On Wed, Dec 17, 2014 at 1:04 PM, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
> On Wednesday 17 December 2014 10:42:52 Geert Uytterhoeven wrote:
>> On Wed, Dec 17, 2014 at 9:30 AM, Geert Uytterhoeven wrote:
>> > On Wed, Dec 17, 2014 at 3:08 AM, Laurent Pinchart wrote:
>> >>>> Kzm9g-reference still hangs at "Calibrating local timer..." (it did
>> >>>> work at some point in the past).
>> >>
>> >> kzm9g-reference boots for me with kzm9g_defconfig on Simon's devel branch
>> >> with
>> >>
>> > OK.
>> >
>> > I had expected the breakage to be something in my tree, either an issue in
>> > a -next branch I'm using, an interaction with the CCF patches or so, or a
>> > config issue (e.g. CONFIG_CPU_IDLE became broken lately if the TWD is
>> > not in DT).
>>
>> Kzm9g-reference hangs at "Calibrating local timer..." because I added the
>> TWD to sh73a0.dtsi (http://www.spinics.net/lists/arm-kernel/msg383413.html).
>>
>> As twd_get_clock() does
>>
>>         if (np)
>>                 twd_clk = of_clk_get(np, 0);
>>         else
>>                 twd_clk = clk_get_sys("smp_twd", NULL);
>>
>> it's not DT-without-CCF proof, and kzm9g-reference cannot get its clock :-(
>>
>> So the TWD node should be in sh73a0-kzm9g-multiplatform.dts, and we need
>> more dts files instead of less...
>>
>> Note that I added the TWD node to DT to fix a hang on kzm9g-multiplatform
>> with CONFIG_CPU_IDLE=y (recently introduced "regression" in core code)
>> after:
>>
>>      DMA: preallocated 256 KiB pool for atomic coherent allocations
>>
>> On kzm9g-legacy the TWD is instantiated from C board code
>> (machine_desc.init_time = sh73a0_earlytimer_init), so CONFIG_CPU_IDLE=y
>> does not hang. Despite https://lkml.org/lkml/2014/12/2/339.
>>
>> On kzm9g-reference, the TWD is not instantiated, causing the same hang.
>> If I instantiate the TWD from C board code there, it fails with
>>
>>     twd: can't register interrupt 29 (-22)
>>
>> which looks like a symptom of https://lkml.org/lkml/2014/12/2/339
>>
>> So no cookies for users of several -legacy and -reference platforms in
>> v3.19-rc1 this Monday...
>
> I'm not sure if fixing that would be worth it. Should we instead try to
> replace kzm9g-legacy and kzm9g-reference by kzm9g-multiplatform in v3.20 ?

v3.20 is reasonable. Except that some breakage will arrive in v3.19-rc1.
So there will be a brokenness window for the kzm9g platform between
v3.18 and v3.20.

> What are we missing ?
>
> - The DIV6 multiparent series has been merged by Mike, and the sh73a0 CCF is
> nearly ready.

Yep.

> - We need proper BSC support to get LAN working, although it could be worked
> around temporarily by specifying the BSC clock in the LAN node if I recall
> correctly.

Working on that. I hope to send out v2 later today...

> - Accelerometer and RTC have no DT bindings, but they should work with the I2C
> core OF match support.

I have RTC in my DTS, and it works.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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