linux-kernel - Re: [PATCH v7 00/42] ARM: davinci: convert to common clock framework

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Date:   Wed, 21 Feb 2018 11:05:41 -0600
From:   David Lechner <david@...hnology.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     linux-clk@...r.kernel.org, devicetree <devicetree@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Adam Ford <aford173@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 00/42] ARM: davinci: convert to common clock framework

On 02/21/2018 06:01 AM, Bartosz Golaszewski wrote:
> 2018-02-20 19:39 GMT+01:00 David Lechner <david@...hnology.com>:
>> On 02/20/2018 07:33 AM, Bartosz Golaszewski wrote:
>>>
>>> 2018-02-19 21:21 GMT+01:00 David Lechner <david@...hnology.com>:
>>>>
>>>> This series converts mach-davinci to use the common clock framework.
>>>>
>>>>
>>>
>>> Hi David,
>>>
>>> just some quick results from today's playing with v7.
>>>
>>> I started out with da850-lcdk with my standard rootfs over NFS. I was
>>> not able to boot to console so far. The first problem is that mdio
>>> fails to probe:
>>>
>>> libphy: Fixed MDIO Bus: probed
>>> davinci_mdio 1e24000.mdio: davinci mdio revision 1.5, bus freq 2200000
>>> davinci_mdio 1e24000.mdio: no live phy, scanning all
>>> davinci_mdio: probe of 1e24000.mdio failed with error -5> After some
>>> digging I noticed that the supplied clock rate differs
>>> between mainline (114000000Hz) vs common-clock-v7 (18000000). Since
>>> we're not setting the rate in mdio, using LPSC_SET_RATE_PARENT would
>>> not help like with lcdc.
>>
>>
>> Can you post the output of this command so that I can see how your
>> clocks are setup:
>>
>> cat /sys/kernel/debug/clk/clk_summary
>>
>>
>>>
>>> After that, the boot just hangs without ever getting to emac's probe.
>>
>>
>> Using your workaround, can you run:
>>
>> cat /sys/kernel/debug/pm_genpd/pm_genpd_summary
>>
>> If you see:
>>    1e27000.clock-controller: emac  off-0
>>
>> then genpd is not working like it is supposed to. You should see something
>> like this for device that are working:
>>            1e27000.clock-controller: uart2  on
>>      /devices/platform/soc@...0000/1d0d000.serial        active
>>
>>
>>>
>>> Once I set the emac clock to always enabled (a workaround that was
>>> necessary with v6, but could be dropped with my first
>>> genpd-in-a-separate-driver attempt), I'm getting a rather strange NULL
>>> pointer dereference:
>>
>>
>> I noticed this too when adding the power-domains property to some device
>> tree nodes. This is part of the reason why I didn't add it everywhere.
>> I wasn't able to figure out the cause of this yet. As a work around
>> though, please try removing the power-domains property from the emac
>> and mdio nodes and use your previous workaround of having an always
>> enabled clock.
>>
>>
> 
> When I use any of the workarounds I just keep getting more problems
> (e.g. [1] from blk and pinctrl). I only had a couple hours today to
> play with it but it seems to me we have some memory corruption
> somewhere. I'll check the initialization order of all the frameworks
> involved tomorrow.
> 
> Best regards,
> Bartosz
> 
> [1] https://pastebin.com/75mkkuJL
> 

I wonder if we need to delete all of the __init and __initconst attributes
now that this has been converted to platform devices.