From: Sam Protsenko <semen.protsenko@linaro.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Rob Herring <robh+dt@kernel.org>, Mark Brown <broonie@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jaewon Kim <jaewon02.kim@samsung.com>,
Chanho Park <chanho61.park@samsung.com>,
David Virag <virag.david003@gmail.com>,
Youngmin Nam <youngmin.nam@samsung.com>,
devicetree@vger.kernel.org, linux-spi@vger.kernel.org,
linux-serial@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
linux-i2c@vger.kernel.org
Subject: Re: [PATCH 5/8] tty: serial: samsung: Enable console as module
Date: Mon, 29 Nov 2021 22:18:31 +0200 [thread overview]
Message-ID: <CAPLW+4=Xp0m3ycm5c1WSJGtr6vRxx1fsW0MOo65fXMfaB1sR+w@mail.gmail.com> (raw)
In-Reply-To: <9a51b37b-d2c4-fb73-bd3f-447c94a66c82@canonical.com>
On Mon, 29 Nov 2021 at 10:52, Krzysztof Kozlowski
<krzysztof.kozlowski@canonical.com> wrote:
>
> On 27/11/2021 23:32, Sam Protsenko wrote:
> > Enable serial driver to be built as a module. To do so, init the console
> > support on driver/module load instead of using console_initcall().
> >
> > This is needed for proper support of USIv2 driver (which can be built as
> > a module, which in turn makes SERIAL_SAMSUNG be a module too). It also
> > might be useful for Android GKI modularization efforts.
> >
> > Inspired by commit 87a0b9f98ac5 ("tty: serial: meson: enable console as
> > module").
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> > ---
> > drivers/tty/serial/Kconfig | 2 +-
> > drivers/tty/serial/samsung_tty.c | 21 +++++++++++++++++++--
> > 2 files changed, 20 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > index fc543ac97c13..0e5ccb25bdb1 100644
> > --- a/drivers/tty/serial/Kconfig
> > +++ b/drivers/tty/serial/Kconfig
> > @@ -263,7 +263,7 @@ config SERIAL_SAMSUNG_UARTS
> >
> > config SERIAL_SAMSUNG_CONSOLE
> > bool "Support for console on Samsung SoC serial port"
> > - depends on SERIAL_SAMSUNG=y
> > + depends on SERIAL_SAMSUNG
> > select SERIAL_CORE_CONSOLE
> > select SERIAL_EARLYCON
> > help
> > diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> > index f986a9253dc8..92a63e9392ed 100644
> > --- a/drivers/tty/serial/samsung_tty.c
> > +++ b/drivers/tty/serial/samsung_tty.c
> > @@ -1720,10 +1720,10 @@ static int __init s3c24xx_serial_console_init(void)
> > register_console(&s3c24xx_serial_console);
> > return 0;
> > }
> > -console_initcall(s3c24xx_serial_console_init);
> >
> > #define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
> > #else
> > +static inline int s3c24xx_serial_console_init(void) { return 0; }
> > #define S3C24XX_SERIAL_CONSOLE NULL
> > #endif
> >
> > @@ -2898,7 +2898,24 @@ static struct platform_driver samsung_serial_driver = {
> > },
> > };
> >
> > -module_platform_driver(samsung_serial_driver);
> > +static int __init samsung_serial_init(void)
> > +{
> > + int ret;
> > +
> > + ret = s3c24xx_serial_console_init();
> > + if (ret)
> > + return ret;
>
> This will trigger warns on module re-loading, won't it? Either suppress
> unbind or cleanup in module exit.
>
I guess that's already taken care of in samsung_serial_remove(): it's
doing uart_remove_one_port(), which in turn does unregister_console().
So I don't think anything extra should be done on module exit. Or I'm
missing something?
That case (unload/load) actually doesn't work well in my case: serial
console doesn't work after doing "modprobe -r samsung_tty; modprobe
samsung_tty" (but it works fine e.g. in case of i2c_exynos5 driver).
Not sure what is wrong, but I can see that my board keeps running
(heartbeat LED is still blinking). Not even sure if that use case
(unload/load) was ever functional before.
Anyway, please let me know if you think something should be done about
this particular patch. Right now I don't see anything missing.
> > +
> > + return platform_driver_register(&samsung_serial_driver);
> > +}
> > +
> > +static void __exit samsung_serial_exit(void)
> > +{
> > + platform_driver_unregister(&samsung_serial_driver);
> > +}
> > +
> > +module_init(samsung_serial_init);
> > +module_exit(samsung_serial_exit);
> >
> > #ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
> > /*
> >
>
>
> Best regards,
> Krzysztof
next prev parent reply other threads:[~2021-11-29 22:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-27 22:32 [PATCH 0/8] soc: samsung: Add USIv2 driver Sam Protsenko
2021-11-27 22:32 ` [PATCH 1/8] dt-bindings: soc: samsung: Add Exynos USIv2 bindings Sam Protsenko
2021-11-27 22:32 ` [PATCH 2/8] dt-bindings: soc: samsung: Add Exynos USIv2 bindings doc Sam Protsenko
2021-11-29 8:33 ` Krzysztof Kozlowski
2021-11-27 22:32 ` [PATCH 3/8] soc: samsung: Add USIv2 driver Sam Protsenko
2021-11-29 8:49 ` Krzysztof Kozlowski
2021-11-27 22:32 ` [PATCH 4/8] tty: serial: samsung: Remove USI initialization Sam Protsenko
2021-11-28 14:28 ` Greg Kroah-Hartman
2021-11-28 16:26 ` Sam Protsenko
2021-11-28 17:03 ` Sam Protsenko
2021-11-27 22:32 ` [PATCH 5/8] tty: serial: samsung: Enable console as module Sam Protsenko
2021-11-29 8:52 ` Krzysztof Kozlowski
2021-11-29 20:18 ` Sam Protsenko [this message]
2021-11-29 20:38 ` Sam Protsenko
2021-11-27 22:32 ` [PATCH 6/8] tty: serial: Make SERIAL_SAMSUNG=y impossible when EXYNOS_USI_V2=m Sam Protsenko
2021-11-28 14:27 ` Greg Kroah-Hartman
2021-11-28 23:54 ` Sam Protsenko
2021-11-27 22:32 ` [PATCH 7/8] i2c: Make I2C_EXYNOS5=y " Sam Protsenko
2021-11-29 0:02 ` Sam Protsenko
2021-11-27 22:32 ` [PATCH 8/8] spi: Make SPI_S3C64XX=y " Sam Protsenko
2021-11-29 0:02 ` Sam Protsenko
2021-11-28 3:15 ` [PATCH 0/8] soc: samsung: Add USIv2 driver David Virag
2021-11-29 9:02 ` Krzysztof Kozlowski
2021-11-29 13:56 ` Sam Protsenko
2021-11-29 17:35 ` Krzysztof Kozlowski
2021-11-29 19:19 ` David Virag
2021-11-30 0:01 ` Sam Protsenko
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