linux-kernel - RE: [PATCH] tty: goldfish: Enable 'earlycon' only if built-in

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Date:   Thu, 30 Nov 2017 09:04:57 +0000
From:   Miodrag Dinic <Miodrag.Dinic@...s.com>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Aleksandar Markovic <Aleksandar.Markovic@...s.com>,
        Goran Ferenc <Goran.Ferenc@...s.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.cz>
Subject: RE: [PATCH] tty: goldfish: Enable 'earlycon' only if built-in

Thank you Sebastian,

Reviewed-by: Miodrag Dinic <miodrag.dinic@...s.com>
Acked-by: Miodrag Dinic <miodrag.dinic@...s.com>

Kind regards,
Miodrag

________________________________________
From: Sebastian Andrzej Siewior
Sent: Thursday, November 30, 2017 9:16:31 AM (UTC+01:00) Belgrade, Bratislava, Budapest, Ljubljana, Prague
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman; Jiri Slaby; Miodrag Dinic; Goran Ferenc; Aleksandar Markovic; Sebastian Andrzej Siewior
Subject: [PATCH] tty: goldfish: Enable 'earlycon' only if built-in

Commit 3840ed9548f7 ("tty: goldfish: Implement support for kernel
'earlycon' parameter") breaks an allmodconfig config on x86:
|  LD      vmlinux.o
|  MODPOST vmlinux.o
|drivers/tty/serial/earlycon.o: In function `parse_options':
|drivers/tty/serial/earlycon.c:97: undefined reference to `uart_parse_earlycon'
|Makefile:1005: recipe for target 'vmlinux' failed

earlycon.c::parse_options() invokes uart_parse_earlycon() from serial_core.c
which is compiled=m because GOLDFISH_TTY itself (and most others) are =m.
To avoid that, I'm adding the _CONSOLE config option which is selected if the
GOLDFISH module itself is =y since it doesn't need the early bits for the =m
case (other drivers do the same dance).
The alternative would be to move uart_parse_earlycon() from
serial_core.c to earlycon.c (we don't have that many users of that
function).

Fixes: 3840ed9548f7 ("tty: goldfish: Implement support for kernel
       'earlycon' parameter")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 drivers/tty/Kconfig    | 6 +++++-
 drivers/tty/goldfish.c | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index cc2b4d9433ed..b811442c5ce6 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -394,10 +394,14 @@ config GOLDFISH_TTY
        depends on GOLDFISH
        select SERIAL_CORE
        select SERIAL_CORE_CONSOLE
-       select SERIAL_EARLYCON
        help
          Console and system TTY driver for the Goldfish virtual platform.

+config GOLDFISH_TTY_EARLY_CONSOLE
+       bool
+       default y if GOLDFISH_TTY=y
+       select SERIAL_EARLYCON
+
 config DA_TTY
        bool "DA TTY"
        depends on METAG_DA
diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 381e981dee06..85a500ddbcaa 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -442,6 +442,7 @@ static int goldfish_tty_remove(struct platform_device *pdev)
        return 0;
 }

+#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
 static void gf_early_console_putchar(struct uart_port *port, int ch)
 {
        __raw_writel(ch, port->membase);
@@ -465,6 +466,7 @@ static int __init gf_earlycon_setup(struct earlycon_device *device,
 }

 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
+#endif

 static const struct of_device_id goldfish_tty_of_match[] = {
        { .compatible = "google,goldfish-tty", },
--
2.15.0