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

From: Peter Hurley
Date: Wed Feb 25 2015 - 08:03:13 EST

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@xxxxxxxxxxxxxxxxxx>
> ---
> 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,
>

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