linux-kernel - Re: [PATCH 02/17] clocksource: davinci-timer: new driver

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Date:   Tue, 22 Jan 2019 16:30:07 -0800
From:   Kevin Hilman <khilman@...libre.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>, Sekhar Nori <nsekhar@...com>
Cc:     Kevin Hilman <khilman@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 02/17] clocksource: davinci-timer: new driver

Bartosz Golaszewski <brgl@...ev.pl> writes:

> pon., 14 sty 2019 o 13:20 Sekhar Nori <nsekhar@...com> napisał(a):
>>
>> Hi Bartosz,
>>
>> On 11/01/19 10:51 PM, Bartosz Golaszewski wrote:
>> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>> >
>> > Currently the clocksource and clockevent support for davinci platforms
>> > lives in mach-davinci. It hard-codes many things, used global variables,
>> > implements functionalities unused by any platform and has code fragments
>> > scattered across many (often unrelated) files.
>> >
>> > Implement a new, modern and simplified timer driver and put it into
>> > drivers/clocksource. We still need to support legacy board files so
>> > export a config structure and a function that allows machine code to
>> > register the timer.
>> >
>> > We don't check the return values of regmap reads and writes since with
>> > mmio it's only likely to fail due to programmer's errors.
>> >
>> > We also don't bother freeing resources on errors in
>> > davinci_timer_register() as the system won't boot without a timer anyway.
>> >
>> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
>>
>> With this series, DA830 fails to boot. Rest of the devices are okay from
>> boot perspective.
>>
>> DA830 is pretty unique because it uses the same timer-half for both
>> clocksource and clockevent. May be you can set the same configuration on
>> your DA850 to see the same issue? Else, I will enable low-level debug
>> and try to provide more debug data.
>>
>
> I can't boot da850 with the same config as da830 (0x60 compare
> register, compare irq 74) even with the old timer code. Just to make
> sure: does da830 boot fine with mainline v5.0-rc2?
>
>> Some minor comments below from quick look:
>>
>> > diff --git a/drivers/clocksource/timer-davinci.c b/drivers/clocksource/timer-davinci.c
>> > new file mode 100644
>> > index 000000000000..7282a1fda80f
>> > --- /dev/null
>> > +++ b/drivers/clocksource/timer-davinci.c
>> > @@ -0,0 +1,415 @@
>> > +// SPDX-License-Identifier: GPL-2.0+
>> > +/*
>> > + * TI DaVinci clocksource driver
>> > + *
>> > + * Copyright (C) 2019 Texas Instruments
>> > + * Author: Bartosz Golaszewski <bgolaszewski@...libre.com>
>> > + * (with some parts adopted from code by Kevin Hilman <khilman@...libre.com>)
>>
>> Did you really intend GPL v2 or later? The original code referred to
>> above is marked 2.0 only.
>>
>
> I'm not sure. Should it be GPLv2 only? I'm not well versed with licensing.

I guess it's up to you since you're the author of this new, reworked
driver, but the original one I wrote was GPLv2 only.

Note however that that the choice of v2 only was not out of objection to
v2+ but because I wrote that in 2007, when there was no "+" ;)

Kevin