[PATCH 1/4] OF: Add helper for matching against linux,stdout-path

From: Sascha Hauer <redacted>

devicetrees may have a linux,stdout-path or stdout-path property
in the chosen node describing the console device. This adds a helper
function to match a device against this property and retrieve the options
so a driver can call add_preferred_console for a matching device.

Signed-off-by: Sascha Hauer <redacted>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>
Cc: linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Greg Kroah-Hartman <redacted>
Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org
Cc: Alan Cox <alan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: Nicolas Ferre <redacted>
---
 drivers/of/base.c  |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |    7 +++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index f2f63c8..72c49ce 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c

@@ -1470,3 +1470,49 @@ const char *of_prop_next_string(struct property *prop, const char *cur)
 	return curv;
 }
 EXPORT_SYMBOL_GPL(of_prop_next_string);
+
+/**
+ * of_device_is_stdout_path - check if a device node matches the
+ *			      linux,stdout-path property
+ * @np:		Pointer to the given device_node
+ * @option:	parsed option
+ *
+ * Check if this device node matches the linux,stdout-path property
+ * in the chosen node. return true if yes, false otherwise.
+ */
+int of_device_is_stdout_path(struct device_node *dn, char **option)
+{
+	const char *name;
+	struct device_node *dn_stdout;
+	bool is_stdout = 0;
+	const char *tmp;
+	const char *tmp_option;
+
+	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+	if (name == NULL)
+		name = of_get_property(of_chosen, "stdout-path", NULL);
+
+	if (name == NULL)
+		return 0;
+
+	tmp_option = strchr(name, ':');
+
+	tmp = kstrndup(name, strlen(name) - strlen(tmp_option), GFP_KERNEL);
+	if (!tmp)
+		return 0;
+
+	dn_stdout = of_find_node_by_path(tmp);
+
+	if (dn_stdout && dn_stdout == dn) {
+		is_stdout = 1;
+		tmp_option++;
+		*option = kstrdup(tmp_option, GFP_KERNEL);
+	}
+
+	of_node_put(dn_stdout);
+
+	kfree(tmp);
+
+	return is_stdout;
+}
+EXPORT_SYMBOL_GPL(of_device_is_stdout_path);

diff --git a/include/linux/of.h b/include/linux/of.h
index 681a6c8..6a82e3f 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h

@@ -323,6 +323,8 @@ const char *of_prop_next_string(struct property *prop, const char *cur);
 		s;						\
 		s = of_prop_next_string(prop, s))
 
+int of_device_is_stdout_path(struct device_node *dn, char **option);
+
 #else /* CONFIG_OF */
 
 static inline const char* of_node_full_name(struct device_node *np)

@@ -450,6 +452,11 @@ static inline int of_machine_is_compatible(const char *compat)
 	return 0;
 }
 
+static inline int of_device_is_stdout_path(struct device_node *dn, char **option)
+{
+	return 0;
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #define of_property_for_each_u32(np, propname, prop, p, u) \

-- 
1.7.10.4

From: Sascha Hauer <s.hauer@pengutronix.de>

Traditionally console support is optional for serial drivers. This
makes it non optional for the i.MX driver since it's not worth
asking questions for a feature virtually every user of this driver
wants to have.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-serial@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: kernel@pengutronix.de
Cc: Alan Cox <redacted>
Cc: Grant Likely <redacted>
Cc: Nicolas Ferre <redacted>
---
 drivers/tty/serial/Kconfig |   16 +---------------
 drivers/tty/serial/imx.c   |    8 +-------
 2 files changed, 2 insertions(+), 22 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index b176801..10e5eec 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig

@@ -541,26 +541,12 @@ config SERIAL_IMX
 	bool "IMX serial port support"
 	depends on ARCH_MXC
 	select SERIAL_CORE
+	select SERIAL_CORE_CONSOLE
 	select RATIONAL
 	help
 	  If you have a machine based on a Motorola IMX CPU you
 	  can enable its onboard serial port by enabling this option.
 
-config SERIAL_IMX_CONSOLE
-	bool "Console on IMX serial port"
-	depends on SERIAL_IMX
-	select SERIAL_CORE_CONSOLE
-	help
-	  If you have enabled the serial port on the Motorola IMX
-	  CPU you can make it the console by answering Y to this option.
-
-	  Even if you say Y here, the currently visible virtual console
-	  (/dev/tty0) will still be used as the system console by default, but
-	  you can alter that using a kernel command line option such as
-	  "console=ttySA0". (Try "man bootparam" or see the documentation of
-	  your boot loader (lilo or loadlin) about how to pass options to the
-	  kernel at boot time.)
-
 config SERIAL_UARTLITE
 	tristate "Xilinx uartlite serial port support"
 	depends on PPC32 || MICROBLAZE || MFD_TIMBERDALE

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 5981912..07a8ca1 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c

@@ -1192,7 +1192,6 @@ static struct uart_ops imx_pops = {
 
 static struct imx_port *imx_ports[UART_NR];
 
-#ifdef CONFIG_SERIAL_IMX_CONSOLE
 static void imx_console_putchar(struct uart_port *port, int ch)
 {
 	struct imx_port *sport = (struct imx_port *)port;

@@ -1348,11 +1347,6 @@ static struct console imx_console = {
 	.data		= &imx_reg,
 };
 
-#define IMX_CONSOLE	&imx_console
-#else
-#define IMX_CONSOLE	NULL
-#endif
-
 static struct uart_driver imx_reg = {
 	.owner          = THIS_MODULE,
 	.driver_name    = DRIVER_NAME,

@@ -1360,7 +1354,7 @@ static struct uart_driver imx_reg = {
 	.major          = SERIAL_IMX_MAJOR,
 	.minor          = MINOR_START,
 	.nr             = ARRAY_SIZE(imx_ports),
-	.cons           = IMX_CONSOLE,
+	.cons           = &imx_console,
 };
 
 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)

-- 
1.7.10.4

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <redacted>
Cc: linux-serial@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: kernel@pengutronix.de
Cc: Alan Cox <redacted>
Cc: Grant Likely <redacted>
Cc: Nicolas Ferre <redacted>
---
 drivers/tty/serial/atmel_serial.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 5608b6b..f62a3c3 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c

@@ -1427,6 +1427,7 @@ static struct uart_ops atmel_pops = {
 static void __devinit atmel_of_init_port(struct atmel_uart_port *atmel_port,
 					 struct device_node *np)
 {
+	char *option = NULL;
 	u32 rs485_delay[2];
 
 	/* DMA/PDC usage specification */

@@ -1453,6 +1454,10 @@ static void __devinit atmel_of_init_port(struct atmel_uart_port *atmel_port,
 
 		if (of_get_property(np, "linux,rs485-enabled-at-boot-time", NULL))
 			rs485conf->flags |= SER_RS485_ENABLED;
+	} else if (of_device_is_stdout_path(np, &option)) {
+		pr_info("add preferred console %s%d option=%s\n",
+			ATMEL_DEVICENAME, atmel_port->uart.line, option);
+		add_preferred_console(ATMEL_DEVICENAME, atmel_port->uart.line, option);
 	}
 }
 

-- 
1.7.10.4

On Wed, Nov 21, 2012 at 04:57:05PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:

tmp_option may be NULL.

+	if (!tmp)
+		return 0;
+
+	dn_stdout = of_find_node_by_path(tmp);
+
+	if (dn_stdout && dn_stdout == dn) {
+		is_stdout = 1;
+		tmp_option++;
+		*option = kstrdup(tmp_option, GFP_KERNEL);
+	}
+
+	of_node_put(dn_stdout);

dn_stdout may be NULL aswell.

Sascha

-- 
Pengutronix e.K.                           |                             |
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Hi,

Sascha Hauer writes:

On Wed, Nov 21, 2012 at 04:57:05PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:

quoted

From: Sascha Hauer <s.hauer@pengutronix.de>

devicetrees may have a linux,stdout-path or stdout-path property
in the chosen node describing the console device. This adds a helper
function to match a device against this property and retrieve the options
so a driver can call add_preferred_console for a matching device.

[...]

quoted

+	if (!tmp)
+		return 0;
+
+	dn_stdout = of_find_node_by_path(tmp);
+
+	if (dn_stdout && dn_stdout == dn) {
+		is_stdout = 1;
+		tmp_option++;
+		*option = kstrdup(tmp_option, GFP_KERNEL);
+	}
+
+	of_node_put(dn_stdout);

dn_stdout may be NULL aswell.

which is handled gracefully by of_node_put()...


Lothar Waßmann
-- 
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On Wed, Nov 21, 2012 at 3:57 PM, Jean-Christophe PLAGNIOL-VILLARD
[off-list ref] wrote:

From: Sascha Hauer <s.hauer@pengutronix.de>

devicetrees may have a linux,stdout-path or stdout-path property
in the chosen node describing the console device. This adds a helper
function to match a device against this property and retrieve the options
so a driver can call add_preferred_console for a matching device.

NIce. Looks like the right behaviour, but is a little inefficient.
Since the stdout property doesn't change this code could be called
once right after the tree is unflattened and then cache the pointer to
the node and arguments. Can you add the code to of_alias_scan()?

g.

--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

On 18:03 Wed 21 Nov     , Grant Likely wrote:

On Wed, Nov 21, 2012 at 3:57 PM, Jean-Christophe PLAGNIOL-VILLARD
[off-list ref] wrote:

quoted

From: Sascha Hauer <s.hauer@pengutronix.de>

devicetrees may have a linux,stdout-path or stdout-path property
in the chosen node describing the console device. This adds a helper
function to match a device against this property and retrieve the options
so a driver can call add_preferred_console for a matching device.

NIce. Looks like the right behaviour, but is a little inefficient.
Since the stdout property doesn't change this code could be called
once right after the tree is unflattened and then cache the pointer to
the node anarguments. Can you add the code to of_alias_scan()?

do we assume that we can have only one stdout-path?

I think we could have more serial, framebuffer console

Best Regards,
J.