Re: [PATCH -next 01/13] serial: earlycon: Refactor parse_options into serial core

[Peter Hurley <peter@hurleysoftware.com>]

Hi Joe,

checkpatch warns on the line below:

On 02/24/2015 11:36 AM, Peter Hurley wrote:
> Prepare to support console-defined matching; refactor the command
> line parameter string processing from parse_options() into a
> new core function, uart_parse_earlycon(), which decodes command line
> parameters of the form:
>    earlycon=<name>,io|mmio|mmio32,<addr>,<options>
>    console=<name>,io|mmio|mmio32,<addr>,<options>
>    earlycon=<name>,0x<addr>,<options>
>    console=<name>,0x<addr>,<options>
> 
> Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> ---
>  drivers/tty/serial/earlycon.c    | 39 ++++++++++++----------------------
>  drivers/tty/serial/serial_core.c | 46 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/serial_core.h      |  2 ++
>  3 files changed, 61 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> index 64fe25a..58d6bcd 100644
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -54,44 +54,31 @@ static void __iomem * __init earlycon_map(unsigned long paddr, size_t size)
>  	return base;
>  }
>  
> -static int __init parse_options(struct earlycon_device *device,
> -				char *options)
> +static int __init parse_options(struct earlycon_device *device, char *options)
>  {
>  	struct uart_port *port = &device->port;
> -	int mmio, mmio32, length;
> +	int length;
>  	unsigned long addr;
>  
> -	if (!options)
> -		return -ENODEV;
> +	if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
> +		return -EINVAL;
>  
> -	mmio = !strncmp(options, "mmio,", 5);
> -	mmio32 = !strncmp(options, "mmio32,", 7);
> -	if (mmio || mmio32) {
> -		port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
> -		options += mmio ? 5 : 7;
> -		addr = simple_strtoul(options, NULL, 0);
> +	switch (port->iotype) {
> +	case UPIO_MEM32:
> +		port->regshift = 2;	/* fall-through */
> +	case UPIO_MEM:
>  		port->mapbase = addr;
> -		if (mmio32)
> -			port->regshift = 2;
> -	} else if (!strncmp(options, "io,", 3)) {
> -		port->iotype = UPIO_PORT;
> -		options += 3;
> -		addr = simple_strtoul(options, NULL, 0);
> +		break;
> +	case UPIO_PORT:
>  		port->iobase = addr;
> -		mmio = 0;
> -	} else if (!strncmp(options, "0x", 2)) {
> -		port->iotype = UPIO_MEM;
> -		addr = simple_strtoul(options, NULL, 0);
> -		port->mapbase = addr;
> -	} else {
> +		break;
> +	default:
>  		return -EINVAL;
>  	}
>  
>  	port->uartclk = BASE_BAUD * 16;
>  
> -	options = strchr(options, ',');
>  	if (options) {
> -		options++;
>  		device->baud = simple_strtoul(options, NULL, 0);
>  		length = min(strcspn(options, " ") + 1,
>  			     (size_t)(sizeof(device->options)));
> @@ -100,7 +87,7 @@ static int __init parse_options(struct earlycon_device *device,
>  
>  	if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32)
>  		pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",
> -			mmio32 ? "32" : "",
> +			(port->iotype == UPIO_MEM32) ? "32" : "",
>  			(unsigned long long)port->mapbase,
>  			device->options);
>  	else
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 6a1055a..3f823c26 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1810,6 +1810,52 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
>  }
>  
>  /**
> + *	uart_parse_earlycon - Parse earlycon options
> + *	@p:	  ptr to 2nd field (ie., just beyond '<name>,')
> + *	@iotype:  ptr for decoded iotype (out)
> + *	@addr:    ptr for decoded mapbase/iobase (out)
> + *	@options: ptr for <options> field; NULL if not present (out)
> + *
> + *	Decodes earlycon kernel command line parameters of the form
> + *	   earlycon=<name>,io|mmio|mmio32,<addr>,<options>
> + *	   console=<name>,io|mmio|mmio32,<addr>,<options>
> + *
> + *	The optional form
> + *	   earlycon=<name>,0x<addr>,<options>
> + *	   console=<name>,0x<addr>,<options>
> + *	is also accepted; the returned @iotype will be UPIO_MEM.
> + *
> + *	Returns 0 on success or -EINVAL on failure
> + */
> +int uart_parse_earlycon(char *p, unsigned char *iotype, unsigned long *addr,
> +			char **options)
> +{
> +	if (strncmp(p, "mmio,", 5) == 0) {
> +		*iotype = UPIO_MEM;
> +		p += 5;
> +	} else if (strncmp(p, "mmio32,", 7) == 0) {
> +		*iotype = UPIO_MEM32;
> +		p += 7;
> +	} else if (strncmp(p, "io,", 3) == 0) {
> +		*iotype = UPIO_PORT;
> +		p += 3;
> +	} else if (strncmp(p, "0x", 2) == 0) {
> +		*iotype = UPIO_MEM;
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	*addr = simple_strtoul(p, NULL, 0);

WARNING: simple_strtoul is obsolete, use kstrtoul instead
#136: FILE: drivers/tty/serial/serial_core.c:1848:
+	*addr = simple_strtoul(p, NULL, 0);


simple_strtoul() is _not_ obsolete.
kstrtoul() cannot parse the <addr> field in a string of the form:

	console=<name>,io|mmio|mmio32,<addr>,<options>

kstrtoul() returns EINVAL without the result.

It was pretty fun debugging that without a console :/

Regards,
Peter Hurley

> +	p = strchr(p, ',');
> +	if (p)
> +		p++;
> +
> +	*options = p;
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(uart_parse_earlycon);
> +
> +/**
>   *	uart_parse_options - Parse serial port baud/parity/bits/flow control.
>   *	@options: pointer to option string
>   *	@baud: pointer to an 'int' variable for the baud rate.
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index baf3e1d..cc5c506 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -354,6 +354,8 @@ early_param("earlycon", name ## _setup_earlycon);
>  
>  struct uart_port *uart_get_console(struct uart_port *ports, int nr,
>  				   struct console *c);
> +int uart_parse_earlycon(char *p, unsigned char *iotype, unsigned long *addr,
> +			char **options);
>  void uart_parse_options(char *options, int *baud, int *parity, int *bits,
>  			int *flow);
>  int uart_set_options(struct uart_port *port, struct console *co, int baud,
>