[PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Geert Uytterhoeven]

Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
added compile-test support to the Freescale 16550 driver.  However, as
SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
now enables this driver.

Fix this by dropping the COMPILE_TEST default again, but making the
SERIAL_8250_FSL symbol visible instead.

Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 808268edd2e82a45..0af96f3adab517f6 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
 	  If unsure, say N.
 
 config SERIAL_8250_FSL
-	bool
+	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64 || COMPILE_TEST
+	default PPC || ARM || ARM64
+	help
+	  Selecting this option will add support for the 16550-style serial
+	  port hardware found on Freescale SoCs.
 
 config SERIAL_8250_DW
 	tristate "Support for Synopsys DesignWare 8250 quirks"
-- 
2.25.1

[PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Geert Uytterhoeven]

Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
added compile-test support to the Freescale 16550 driver.  However, as
SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
now enables this driver.

Fix this by dropping the COMPILE_TEST default again, but making the
SERIAL_8250_FSL symbol visible instead.

Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 808268edd2e82a45..0af96f3adab517f6 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
 	  If unsure, say N.
 
 config SERIAL_8250_FSL
-	bool
+	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64 || COMPILE_TEST
+	default PPC || ARM || ARM64
+	help
+	  Selecting this option will add support for the 16550-style serial
+	  port hardware found on Freescale SoCs.
 
 config SERIAL_8250_DW
 	tristate "Support for Synopsys DesignWare 8250 quirks"
-- 
2.25.1

[PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Geert Uytterhoeven]

Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
added compile-test support to the Freescale 16550 driver.  However, as
SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
now enables this driver.

Fix this by dropping the COMPILE_TEST default again, but making the
SERIAL_8250_FSL symbol visible instead.

Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 808268edd2e82a45..0af96f3adab517f6 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
 	  If unsure, say N.
 
 config SERIAL_8250_FSL
-	bool
+	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64 || COMPILE_TEST
+	default PPC || ARM || ARM64
+	help
+	  Selecting this option will add support for the 16550-style serial
+	  port hardware found on Freescale SoCs.
 
 config SERIAL_8250_DW
 	tristate "Support for Synopsys DesignWare 8250 quirks"
-- 
2.25.1


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[PATCH v2 2/2] serial: 8250: SERIAL_8250_FSL should depend on Freescale platforms

[Geert Uytterhoeven]

The Freescale 16550-style UART is only present on some Freescale SoCs.
Hence tighten the dependencies to prevent asking the user about this
driver, and possibly defaulting it to be enabled, when configuring a
kernel without appropriate Freescale SoC or ACPI support.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 0af96f3adab517f6..a2978b31144e94f2 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -363,7 +363,8 @@ config SERIAL_8250_BCM2835AUX
 config SERIAL_8250_FSL
 	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64
+	depends on FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI) || COMPILE_TEST
+	default FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI)
 	help
 	  Selecting this option will add support for the 16550-style serial
 	  port hardware found on Freescale SoCs.
-- 
2.25.1

[PATCH v2 2/2] serial: 8250: SERIAL_8250_FSL should depend on Freescale platforms

[Geert Uytterhoeven]

The Freescale 16550-style UART is only present on some Freescale SoCs.
Hence tighten the dependencies to prevent asking the user about this
driver, and possibly defaulting it to be enabled, when configuring a
kernel without appropriate Freescale SoC or ACPI support.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 0af96f3adab517f6..a2978b31144e94f2 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -363,7 +363,8 @@ config SERIAL_8250_BCM2835AUX
 config SERIAL_8250_FSL
 	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64
+	depends on FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI) || COMPILE_TEST
+	default FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI)
 	help
 	  Selecting this option will add support for the 16550-style serial
 	  port hardware found on Freescale SoCs.
-- 
2.25.1

[PATCH v2 2/2] serial: 8250: SERIAL_8250_FSL should depend on Freescale platforms

[Geert Uytterhoeven]

The Freescale 16550-style UART is only present on some Freescale SoCs.
Hence tighten the dependencies to prevent asking the user about this
driver, and possibly defaulting it to be enabled, when configuring a
kernel without appropriate Freescale SoC or ACPI support.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Split in two parts.
---
 drivers/tty/serial/8250/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 0af96f3adab517f6..a2978b31144e94f2 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -363,7 +363,8 @@ config SERIAL_8250_BCM2835AUX
 config SERIAL_8250_FSL
 	bool "Freescale 16550-style UART support (8250 based driver)"
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64
+	depends on FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI) || COMPILE_TEST
+	default FSL_SOC || ARCH_LAYERSCAPE || SOC_LS1021A || (ARM64 && ACPI)
 	help
 	  Selecting this option will add support for the 16550-style serial
 	  port hardware found on Freescale SoCs.
-- 
2.25.1


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Re: [PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Johan Hovold]

On Fri, Sep 24, 2021 at 09:12:30AM +0200, Geert Uytterhoeven wrote:
> Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> added compile-test support to the Freescale 16550 driver.  However, as
> SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
> now enables this driver.
> 
> Fix this by dropping the COMPILE_TEST default again, but making the
> SERIAL_8250_FSL symbol visible instead.
> 
> Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> v2:
>   - Split in two parts.

I realised that we can do better than this. I've prepared a patch that
preserves the old behaviour of always enabling the option on platforms
that may need it while also not enabling it by default when compile
testing.

Note that SERIAL_8250_FSL only enables a workaround for an erratum in
the Freescale UARTs in the 8250 driver (leaving the later added ACPI
support aside) and we shouldn't make it easier to disable it by mistake.

> ---
>  drivers/tty/serial/8250/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index 808268edd2e82a45..0af96f3adab517f6 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
>  	  If unsure, say N.
>  
>  config SERIAL_8250_FSL
> -	bool
> +	bool "Freescale 16550-style UART support (8250 based driver)"
>  	depends on SERIAL_8250_CONSOLE
> -	default PPC || ARM || ARM64 || COMPILE_TEST
> +	default PPC || ARM || ARM64
> +	help
> +	  Selecting this option will add support for the 16550-style serial
> +	  port hardware found on Freescale SoCs.
>  
>  config SERIAL_8250_DW
>  	tristate "Support for Synopsys DesignWare 8250 quirks"

Johan

Re: [PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Johan Hovold]

On Fri, Sep 24, 2021 at 09:12:30AM +0200, Geert Uytterhoeven wrote:
> Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> added compile-test support to the Freescale 16550 driver.  However, as
> SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
> now enables this driver.
> 
> Fix this by dropping the COMPILE_TEST default again, but making the
> SERIAL_8250_FSL symbol visible instead.
> 
> Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> v2:
>   - Split in two parts.

I realised that we can do better than this. I've prepared a patch that
preserves the old behaviour of always enabling the option on platforms
that may need it while also not enabling it by default when compile
testing.

Note that SERIAL_8250_FSL only enables a workaround for an erratum in
the Freescale UARTs in the 8250 driver (leaving the later added ACPI
support aside) and we shouldn't make it easier to disable it by mistake.

> ---
>  drivers/tty/serial/8250/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index 808268edd2e82a45..0af96f3adab517f6 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
>  	  If unsure, say N.
>  
>  config SERIAL_8250_FSL
> -	bool
> +	bool "Freescale 16550-style UART support (8250 based driver)"
>  	depends on SERIAL_8250_CONSOLE
> -	default PPC || ARM || ARM64 || COMPILE_TEST
> +	default PPC || ARM || ARM64
> +	help
> +	  Selecting this option will add support for the 16550-style serial
> +	  port hardware found on Freescale SoCs.
>  
>  config SERIAL_8250_DW
>  	tristate "Support for Synopsys DesignWare 8250 quirks"

Johan

Re: [PATCH v2 1/2] serial: 8250: SERIAL_8250_FSL should not default to y when compile-testing

[Johan Hovold]

On Fri, Sep 24, 2021 at 09:12:30AM +0200, Geert Uytterhoeven wrote:
> Commit b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> added compile-test support to the Freescale 16550 driver.  However, as
> SERIAL_8250_FSL is an invisible symbol, merely enabling compile-testing
> now enables this driver.
> 
> Fix this by dropping the COMPILE_TEST default again, but making the
> SERIAL_8250_FSL symbol visible instead.
> 
> Fixes: b1442c55ce8977aa ("serial: 8250: extend compile-test coverage")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> v2:
>   - Split in two parts.

I realised that we can do better than this. I've prepared a patch that
preserves the old behaviour of always enabling the option on platforms
that may need it while also not enabling it by default when compile
testing.

Note that SERIAL_8250_FSL only enables a workaround for an erratum in
the Freescale UARTs in the 8250 driver (leaving the later added ACPI
support aside) and we shouldn't make it easier to disable it by mistake.

> ---
>  drivers/tty/serial/8250/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index 808268edd2e82a45..0af96f3adab517f6 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -361,9 +361,12 @@ config SERIAL_8250_BCM2835AUX
>  	  If unsure, say N.
>  
>  config SERIAL_8250_FSL
> -	bool
> +	bool "Freescale 16550-style UART support (8250 based driver)"
>  	depends on SERIAL_8250_CONSOLE
> -	default PPC || ARM || ARM64 || COMPILE_TEST
> +	default PPC || ARM || ARM64
> +	help
> +	  Selecting this option will add support for the 16550-style serial
> +	  port hardware found on Freescale SoCs.
>  
>  config SERIAL_8250_DW
>  	tristate "Support for Synopsys DesignWare 8250 quirks"

Johan

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[PATCH] serial: 8250: allow disabling of Freescale 16550 compile test

[Johan Hovold]

The SERIAL_8250_FSL option is used to enable a workaround for a
break-detection erratum for Freescale 16550 UARTs in the 8250 driver and
is currently also used to enable support for ACPI enumeration.

It is enabled on PPC, ARM and ARM64 whenever 8250 console support is
enabled (since the quirk is needed for sysrq handling).

Commit b1442c55ce89 ("serial: 8250: extend compile-test coverage")
enabled compile testing of the code in question but did not provide a
means to disable the option when COMPILE_TEST is enabled.

Add a conditional input prompt instead so that SERIAL_8250_FSL is no
longer enabled by default when compile testing while continuing to
always enable the quirk for platforms that may need it.

Fixes: b1442c55ce89 ("serial: 8250: extend compile-test coverage")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/tty/serial/8250/Kconfig | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 71ae16de0f90..39fc96dc2531 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -361,9 +361,13 @@ config SERIAL_8250_BCM2835AUX
 	  If unsure, say N.
 
 config SERIAL_8250_FSL
-	bool
+	bool "Freescale 16550 UART support" if COMPILE_TEST && !(PPC || ARM || ARM64)
 	depends on SERIAL_8250_CONSOLE
-	default PPC || ARM || ARM64 || COMPILE_TEST
+	default PPC || ARM || ARM64
+	help
+	  Selecting this option enables a workaround for a break-detection
+	  erratum for Freescale 16550 UARTs in the 8250 driver. It also
+	  enables support for ACPI enumeration.
 
 config SERIAL_8250_DW
 	tristate "Support for Synopsys DesignWare 8250 quirks"
-- 
2.32.0

Re: [PATCH] serial: 8250: allow disabling of Freescale 16550 compile test

[Geert Uytterhoeven]

On Fri, Sep 24, 2021 at 4:13 PM Johan Hovold <johan@kernel.org> wrote:
> The SERIAL_8250_FSL option is used to enable a workaround for a
> break-detection erratum for Freescale 16550 UARTs in the 8250 driver and
> is currently also used to enable support for ACPI enumeration.
>
> It is enabled on PPC, ARM and ARM64 whenever 8250 console support is
> enabled (since the quirk is needed for sysrq handling).
>
> Commit b1442c55ce89 ("serial: 8250: extend compile-test coverage")
> enabled compile testing of the code in question but did not provide a
> means to disable the option when COMPILE_TEST is enabled.
>
> Add a conditional input prompt instead so that SERIAL_8250_FSL is no
> longer enabled by default when compile testing while continuing to
> always enable the quirk for platforms that may need it.
>
> Fixes: b1442c55ce89 ("serial: 8250: extend compile-test coverage")
> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds