[PATCH] S3C: serial: Modify UART low-level debug port initialization procedure.

[PATCH] S3C: serial: Modify UART low-level debug port initialization procedure.

[Thomas Abraham]

The s3c24xx_serial_init_ports function is called only during low-level
debug port initialization. This function intializes all the available
uart ports when called, but it can be reduced to initializing just the
port needed for debug message output.

This patch modifies the s3c24xx_serial_init_ports to initialize only the
uart port that will be used for low-level debug output. The UART port
that is used for low-level debug output is found from the config option
S3C_LOWLEVEL_UART_PORT.

Since the functionlity of the s3c24xx_serial_init_ports function has
changed, it has been renamed as s3c24xx_serial_init_console_port by
this patch.

This patch is required on platforms that use different platform
configuration for available instances of UART module. For instance,
FIFO sizes could be different for each instance of UART. Such platforms
pass mutiple instances of platform configuration to the serial driver
instead of just one. The serial console init can then be specified as
below in the platform specific code.

s3c24xx_console_init(&s5p_serial_drv, \
	&s5p_uart_inf[CONFIG_S3C_LOWLEVEL_UART_PORT]);

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
---
 drivers/serial/samsung.c |   22 ++++++++++------------
 1 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/serial/samsung.c b/drivers/serial/samsung.c
index 52e3df1..dc9c51e 100644
--- a/drivers/serial/samsung.c
+++ b/drivers/serial/samsung.c
@@ -1368,26 +1368,24 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 
 }
 
-/* s3c24xx_serial_init_ports
+/* s3c24xx_serial_init_console_port
  *
- * initialise the serial ports from the machine provided initialisation
- * data.
+ * initialise the serial port, which used as console, from the machine 
+ * provided initialisation data.
 */
 
-static int s3c24xx_serial_init_ports(struct s3c24xx_uart_info *info)
+static int s3c24xx_serial_init_console_port(struct s3c24xx_uart_info *info)
 {
 	struct s3c24xx_uart_port *ptr = s3c24xx_serial_ports;
 	struct platform_device **platdev_ptr;
-	int i;
 
-	dbg("s3c24xx_serial_init_ports: initialising ports...\n");
+	dbg("s3c24xx_serial_init_console_port: initialising ports...\n");
 
 	platdev_ptr = s3c24xx_uart_devs;
-
-	for (i = 0; i < CONFIG_SERIAL_SAMSUNG_UARTS; i++, ptr++, platdev_ptr++) {
-		s3c24xx_serial_init_port(ptr, info, *platdev_ptr);
-	}
-
+	ptr += CONFIG_S3C_LOWLEVEL_UART_PORT;
+	platdev_ptr += CONFIG_S3C_LOWLEVEL_UART_PORT;
+	
+	s3c24xx_serial_init_port(ptr, info, *platdev_ptr);
 	return 0;
 }
 
@@ -1469,7 +1467,7 @@ int s3c24xx_serial_initconsole(struct platform_driver *drv,
 		return 0;
 
 	s3c24xx_serial_console.data = &s3c24xx_uart_drv;
-	s3c24xx_serial_init_ports(info);
+	s3c24xx_serial_init_console_port(info);
 
 	register_console(&s3c24xx_serial_console);
 	return 0;
-- 
1.6.3.3

Re: [PATCH] S3C: serial: Modify UART low-level debug port initialization procedure.

[Ben Dooks]

On Wed, Jan 13, 2010 at 09:10:20AM +0900, Thomas Abraham wrote:
> The s3c24xx_serial_init_ports function is called only during low-level
> debug port initialization. This function intializes all the available
> uart ports when called, but it can be reduced to initializing just the
> port needed for debug message output.
> 
> This patch modifies the s3c24xx_serial_init_ports to initialize only the
> uart port that will be used for low-level debug output. The UART port
> that is used for low-level debug output is found from the config option
> S3C_LOWLEVEL_UART_PORT.

Not always, console=ttySAC<x> could also be used to find the console.

We could change the s3c24xx_serial_initconsole() call to take a
'struct s3c24xx_uart_info **info'and change init_ports to take the
same. This does unfortunately mean that each of the s3cxxx.c serial
drivers will need to be changed.

You could change s3c24xx_console_init() to fill an array of info before
calling s3c24xx_serial_initconsole() in drivers/serial/samsung.h and
then have the s5pc110 serial code do its own console initialisation
without using the s3c24xx_console_init() macro.

If you don't want to change s3c24xx_console_init() to create an array,
then you could always change s3c24xx_serial_initconsole() to take
a third argument, so it would be:

s3c24xx_serial_initconsole(struct platform_driver *drv,
		           struct s3c24xx_uart_info *info,
			   struct s3c24xx_uart_info *infos)

and then change the behaviour of s3c24xx_serial_init_ports() if infos is
NULL, use the info field, otherwise take the info from infos+hwport.
 
There may of course be other options.

> Since the functionlity of the s3c24xx_serial_init_ports function has
> changed, it has been renamed as s3c24xx_serial_init_console_port by
> this patch.
> 
> This patch is required on platforms that use different platform
> configuration for available instances of UART module. For instance,
> FIFO sizes could be different for each instance of UART. Such platforms
> pass mutiple instances of platform configuration to the serial driver
> instead of just one. The serial console init can then be specified as
> below in the platform specific code.
> 
> s3c24xx_console_init(&s5p_serial_drv, \
> 	&s5p_uart_inf[CONFIG_S3C_LOWLEVEL_UART_PORT]);
> 
> Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
> ---
>  drivers/serial/samsung.c |   22 ++++++++++------------
>  1 files changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/serial/samsung.c b/drivers/serial/samsung.c
> index 52e3df1..dc9c51e 100644
> --- a/drivers/serial/samsung.c
> +++ b/drivers/serial/samsung.c
> @@ -1368,26 +1368,24 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
>  
>  }
>  
> -/* s3c24xx_serial_init_ports
> +/* s3c24xx_serial_init_console_port
>   *
> - * initialise the serial ports from the machine provided initialisation
> - * data.
> + * initialise the serial port, which used as console, from the machine 
> + * provided initialisation data.
>  */
>  
> -static int s3c24xx_serial_init_ports(struct s3c24xx_uart_info *info)
> +static int s3c24xx_serial_init_console_port(struct s3c24xx_uart_info *info)
>  {
>  	struct s3c24xx_uart_port *ptr = s3c24xx_serial_ports;
>  	struct platform_device **platdev_ptr;
> -	int i;
>  
> -	dbg("s3c24xx_serial_init_ports: initialising ports...\n");
> +	dbg("s3c24xx_serial_init_console_port: initialising ports...\n");
>  
>  	platdev_ptr = s3c24xx_uart_devs;
> -
> -	for (i = 0; i < CONFIG_SERIAL_SAMSUNG_UARTS; i++, ptr++, platdev_ptr++) {
> -		s3c24xx_serial_init_port(ptr, info, *platdev_ptr);
> -	}
> -
> +	ptr += CONFIG_S3C_LOWLEVEL_UART_PORT;
> +	platdev_ptr += CONFIG_S3C_LOWLEVEL_UART_PORT;
> +	
> +	s3c24xx_serial_init_port(ptr, info, *platdev_ptr);
>  	return 0;
>  }
>  
> @@ -1469,7 +1467,7 @@ int s3c24xx_serial_initconsole(struct platform_driver *drv,
>  		return 0;
>  
>  	s3c24xx_serial_console.data = &s3c24xx_uart_drv;
> -	s3c24xx_serial_init_ports(info);
> +	s3c24xx_serial_init_console_port(info);
>  
>  	register_console(&s3c24xx_serial_console);
>  	return 0;
> -- 
> 1.6.3.3
> 
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-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.