[PATCH v3 0/5] serial: 8250: fixes for modular build

[PATCH v3 0/5] serial: 8250: fixes for modular build

[Arnd Bergmann]

Hi Greg,

This is a resend of my last week's 8250 series, with a couple of
issues fixed as pointed out by Paul Gortmaker.

Masahiro Yamada had an idea for a nicer solution to the problem of
a modular build, but after some back and forth, the conclusion was
that this does not work any more after the rework done by
Peter Hurley, so we are back to my original approach.

I've done many compile tests over the last week and found another
corner case in the Ingenic driver patch, which is now also fixed,
and I'm no longer getting any invalid symbol references here or
in other drivers.

	Arnd

[PATCH v3 1/5] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Arnd Bergmann]

This reverts commit d72d391c126e ("drivers/tty/serial: make
8250/8250_mtk.c explicitly non-modular"), which intended to remove dead
code but did not have the desired effect when the main 8250 driver was
a module itself.

This would normally result in a link error, but as the entire
drivers/tty/serial/8250/ directory is only entered when CONFIG_SERIAL_8250
is set, we never notice that the driver does not get built in this
configuration.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/tty/serial/8250/8250_mtk.c | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 9038843cadc7..6ecc6e3e82dc 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -16,7 +16,7 @@
  */
 #include <linux/clk.h>
 #include <linux/io.h>
-#include <linux/init.h>
+#include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
@@ -245,6 +245,23 @@ static int mtk8250_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int mtk8250_remove(struct platform_device *pdev)
+{
+	struct mtk8250_data *data = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	serial8250_unregister_port(data->line);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		mtk8250_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
 static int __maybe_unused mtk8250_suspend(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
@@ -273,18 +290,18 @@ static const struct of_device_id mtk8250_of_match[] = {
 	{ .compatible = "mediatek,mt6577-uart" },
 	{ /* Sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, mtk8250_of_match);
 
 static struct platform_driver mtk8250_platform_driver = {
 	.driver = {
-		.name			= "mt6577-uart",
-		.pm			= &mtk8250_pm_ops,
-		.of_match_table		= mtk8250_of_match,
-		.suppress_bind_attrs	= true,
-
+		.name		= "mt6577-uart",
+		.pm		= &mtk8250_pm_ops,
+		.of_match_table	= mtk8250_of_match,
 	},
 	.probe			= mtk8250_probe,
+	.remove			= mtk8250_remove,
 };
-builtin_platform_driver(mtk8250_platform_driver);
+module_platform_driver(mtk8250_platform_driver);
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 static int __init early_mtk8250_setup(struct earlycon_device *device,
@@ -300,3 +317,7 @@ static int __init early_mtk8250_setup(struct earlycon_device *device,
 
 OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
 #endif
+
+MODULE_AUTHOR("Matthias Brugger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
-- 
2.7.0

[PATCH v3 2/5] Revert "drivers/tty/serial: make 8250/8250_ingenic.c explicitly non-modular"

[Arnd Bergmann]

This reverts commit cafe1ac64023  ("drivers/tty: make serial
8250_ingenic.c explicitly non-modular"), which attempted to remove dead
code but did not have the desired effect when the main 8250 driver was
a loadable module itself.

This would normally result in a link error, but as the entire
drivers/tty/serial/8250/ directory is only entered when CONFIG_SERIAL_8250
is set, we never notice that the driver does not get built in this
configuration.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/tty/serial/8250/8250_ingenic.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index b4e1d39805b2..97b78558caed 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -4,8 +4,6 @@
  *
  * Ingenic SoC UART support
  *
- * Author: Paul Burton <paul.burton@imgtec.com>
- *
  * This program is free software; you can redistribute	 it and/or modify it
  * under  the terms of	 the GNU General  Public License as published by the
  * Free Software Foundation;  either version 2 of the	License, or (at your
@@ -20,7 +18,7 @@
 #include <linux/console.h>
 #include <linux/io.h>
 #include <linux/libfdt.h>
-#include <linux/init.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/of_device.h>
@@ -303,6 +301,16 @@ out:
 	return err;
 }
 
+static int ingenic_uart_remove(struct platform_device *pdev)
+{
+	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
+
+	serial8250_unregister_port(data->line);
+	clk_disable_unprepare(data->clk_module);
+	clk_disable_unprepare(data->clk_baud);
+	return 0;
+}
+
 static const struct ingenic_uart_config jz4740_uart_config = {
 	.tx_loadsz = 8,
 	.fifosize = 16,
@@ -325,13 +333,19 @@ static const struct of_device_id of_match[] = {
 	{ .compatible = "ingenic,jz4780-uart", .data = &jz4780_uart_config },
 	{ /* sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, of_match);
 
 static struct platform_driver ingenic_uart_platform_driver = {
 	.driver = {
-		.name			= "ingenic-uart",
-		.of_match_table		= of_match,
-		.suppress_bind_attrs	= true,
+		.name		= "ingenic-uart",
+		.of_match_table	= of_match,
 	},
 	.probe			= ingenic_uart_probe,
+	.remove			= ingenic_uart_remove,
 };
-builtin_platform_driver(ingenic_uart_platform_driver);
+
+module_platform_driver(ingenic_uart_platform_driver);
+
+MODULE_AUTHOR("Paul Burton");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Ingenic SoC UART driver");
-- 
2.7.0

[PATCH v3 3/5] serial: 8250/uniphier: fix modular build

[Arnd Bergmann]

The newly added uniphier serial port driver fails to build as
a loadable module when the base 8250 driver is built-in and
its console support enabled:

ERROR: "early_serial8250_setup" [drivers/tty/serial/8250/8250_uniphier.ko] undefined!

This changes the driver to only provide the early console support
if it is built-in itself as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/tty/serial/8250/8250_uniphier.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index bab6b3ae2540..1b7bd26555b7 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -35,7 +35,7 @@ struct uniphier8250_priv {
 	spinlock_t atomic_write_lock;
 };
 
-#ifdef CONFIG_SERIAL_8250_CONSOLE
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE)
 static int __init uniphier_early_console_setup(struct earlycon_device *device,
 					       const char *options)
 {
-- 
2.7.0

[PATCH v3 4/5] serial: 8250/ingenic: fix building with SERIAL_8250=m

[Arnd Bergmann]

The Ingenic 8250 driver has a 'bool' Kconfig symbol, but that
breaks when SERIAL_8250 is a loadable module:

drivers/tty/built-in.o: In function `ingenic_uart_probe':
8250_ingenic.c:(.text+0x1c1a0): undefined reference to `serial8250_register_8250_port'

This changes the symbol to a 'tristate', plus a dependency on
SERIAL_8250, which makes it work again. Unlike the other
soc-specific backends, this one has no dependency on an
architecture or a platform. I'm adding a dependency on
MIPS || COMPILE_TEST as well here, to avoid showing the driver
on architectures that are not interested in it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/tty/serial/8250/8250_ingenic.c | 2 +-
 drivers/tty/serial/8250/Kconfig        | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index 97b78558caed..b0677f610863 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -48,7 +48,7 @@ static const struct of_device_id of_match[];
 #define UART_MCR_MDCE	BIT(7)
 #define UART_MCR_FCM	BIT(6)
 
-#ifdef CONFIG_SERIAL_EARLYCON
+#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 static struct earlycon_device *early_device;
 
 static uint8_t __init early_in(struct uart_port *port, int offset)
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 67ad6b0d595b..1b0638511ac1 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -384,9 +384,10 @@ config SERIAL_8250_UNIPHIER
 	  serial ports, say Y to this option. If unsure, say N.
 
 config SERIAL_8250_INGENIC
-	bool "Support for Ingenic SoC serial ports"
-	depends on OF_FLATTREE
-	select LIBFDT
+	tristate "Support for Ingenic SoC serial ports"
+	depends on SERIAL_8250
+	depends on (OF_FLATTREE && SERIAL_8250_CONSOLE) || !SERIAL_EARLYCON
+	depends on MIPS || COMPILE_TEST
 	help
 	  If you have a system using an Ingenic SoC and wish to make use of
 	  its UARTs, say Y to this option. If unsure, say N.
-- 
2.7.0

[PATCH v3 5/5] serial: 8250/mediatek: fix building with SERIAL_8250=m

[Arnd Bergmann]

The Mediatek 8250 driver has a 'bool' Kconfig symbol, but that
breaks when SERIAL_8250 is a loadable module:

drivers/tty/built-in.o: In function `mtk8250_set_termios':
:(.text+0x1bee8): undefined reference to `serial8250_do_set_termios'
:(.text+0x1bf10): undefined reference to `uart_get_baud_rate'
:(.text+0x1c09c): undefined reference to `uart_get_divisor'
drivers/tty/built-in.o: In function `mtk8250_do_pm':
:(.text+0x1c0d0): undefined reference to `serial8250_do_pm'
drivers/tty/built-in.o: In function `mtk8250_probe':
:(.text+0x1c2e4): undefined reference to `serial8250_register_8250_port'
serial/8250/8250_mtk.c:287:242: error: data definition has no type or storage class [-Werror]
serial/8250/8250_mtk.c:287:122: error: 'mtk8250_platform_driver_init' defined but not used [-Werror=unused-function]

This changes the symbol to a 'tristate', so the dependency on
SERIAL_8250 also works when that is set to 'm'.
To actually build the driver, we also need to include <linux/module.h>.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
---
 drivers/tty/serial/8250/8250_mtk.c | 2 +-
 drivers/tty/serial/8250/Kconfig    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 6ecc6e3e82dc..a0294f3de4f8 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -303,7 +303,7 @@ static struct platform_driver mtk8250_platform_driver = {
 };
 module_platform_driver(mtk8250_platform_driver);
 
-#ifdef CONFIG_SERIAL_8250_CONSOLE
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && !defined(MODULE)
 static int __init early_mtk8250_setup(struct earlycon_device *device,
 					const char *options)
 {
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 1b0638511ac1..c45a02a7f9e2 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -370,7 +370,7 @@ config SERIAL_8250_LPC18XX
 	  serial port, say Y to this option. If unsure, say Y.
 
 config SERIAL_8250_MT6577
-	bool "Mediatek serial port support"
+	tristate "Mediatek serial port support"
 	depends on SERIAL_8250 && ARCH_MEDIATEK
 	help
 	  If you have a Mediatek based board and want to use the
-- 
2.7.0

Re: [PATCH v3 1/5] Revert "drivers/tty/serial: make 8250/8250_mtk.c explicitly non-modular"

[Matthias Brugger]

On 17/02/16 16:02, Arnd Bergmann wrote:
> This reverts commit d72d391c126e ("drivers/tty/serial: make
> 8250/8250_mtk.c explicitly non-modular"), which intended to remove dead
> code but did not have the desired effect when the main 8250 driver was
> a module itself.
>
> This would normally result in a link error, but as the entire
> drivers/tty/serial/8250/ directory is only entered when CONFIG_SERIAL_8250
> is set, we never notice that the driver does not get built in this
> configuration.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

Acked-by: Matthias Brugger <matthias.bgg@gmail.com>

>   drivers/tty/serial/8250/8250_mtk.c | 35 ++++++++++++++++++++++++++++-------
>   1 file changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 9038843cadc7..6ecc6e3e82dc 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -16,7 +16,7 @@
>    */
>   #include <linux/clk.h>
>   #include <linux/io.h>
> -#include <linux/init.h>
> +#include <linux/module.h>
>   #include <linux/of_irq.h>
>   #include <linux/of_platform.h>
>   #include <linux/platform_device.h>
> @@ -245,6 +245,23 @@ static int mtk8250_probe(struct platform_device *pdev)
>   	return 0;
>   }
>
> +static int mtk8250_remove(struct platform_device *pdev)
> +{
> +	struct mtk8250_data *data = platform_get_drvdata(pdev);
> +
> +	pm_runtime_get_sync(&pdev->dev);
> +
> +	serial8250_unregister_port(data->line);
> +
> +	pm_runtime_disable(&pdev->dev);
> +	pm_runtime_put_noidle(&pdev->dev);
> +
> +	if (!pm_runtime_status_suspended(&pdev->dev))
> +		mtk8250_runtime_suspend(&pdev->dev);
> +
> +	return 0;
> +}
> +
>   static int __maybe_unused mtk8250_suspend(struct device *dev)
>   {
>   	struct mtk8250_data *data = dev_get_drvdata(dev);
> @@ -273,18 +290,18 @@ static const struct of_device_id mtk8250_of_match[] = {
>   	{ .compatible = "mediatek,mt6577-uart" },
>   	{ /* Sentinel */ }
>   };
> +MODULE_DEVICE_TABLE(of, mtk8250_of_match);
>
>   static struct platform_driver mtk8250_platform_driver = {
>   	.driver = {
> -		.name			= "mt6577-uart",
> -		.pm			= &mtk8250_pm_ops,
> -		.of_match_table		= mtk8250_of_match,
> -		.suppress_bind_attrs	= true,
> -
> +		.name		= "mt6577-uart",
> +		.pm		= &mtk8250_pm_ops,
> +		.of_match_table	= mtk8250_of_match,
>   	},
>   	.probe			= mtk8250_probe,
> +	.remove			= mtk8250_remove,
>   };
> -builtin_platform_driver(mtk8250_platform_driver);
> +module_platform_driver(mtk8250_platform_driver);
>
>   #ifdef CONFIG_SERIAL_8250_CONSOLE
>   static int __init early_mtk8250_setup(struct earlycon_device *device,
> @@ -300,3 +317,7 @@ static int __init early_mtk8250_setup(struct earlycon_device *device,
>
>   OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup);
>   #endif
> +
> +MODULE_AUTHOR("Matthias Brugger");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
>