Re: [PATCH 1/3] tty/serial_core: add ISO7816 infrastructure

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jul 11, 2018 at 03:16:36PM +0200, Ludovic Desroches wrote:
> From: Nicolas Ferre <nicolas.ferre@microchip.com>
> 
> Add the ISO7816 ioctl and associated accessors and data structure.
> Drivers can then use this common implementation to handle ISO7816.
> 
> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> [ludovic.desroches@microchip.com: squash and rebase, removal of gpios, checkpatch fixes]
> Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
> ---
>  drivers/tty/serial/serial_core.c  | 49 +++++++++++++++++++++++++++++++++++++++
>  include/linux/serial_core.h       |  3 +++
>  include/uapi/asm-generic/ioctls.h |  2 ++
>  include/uapi/linux/serial.h       | 17 ++++++++++++++
>  4 files changed, 71 insertions(+)

Note, kbuild found build issues with this, please fix up.

Also, here's some comments:

> 
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 9c14a453f73c..c89ac59f6f8c 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1301,6 +1301,47 @@ static int uart_set_rs485_config(struct uart_port *port,
>  	return 0;
>  }
>  
> +static int uart_get_iso7816_config(struct uart_port *port,
> +				   struct serial_iso7816 __user *iso7816)
> +{
> +	unsigned long flags;
> +	struct serial_iso7816 aux;
> +
> +	spin_lock_irqsave(&port->lock, flags);
> +	aux = port->iso7816;

Don't you want to check to see if there is a function for iso7816 before
copying it?  Otherwise it's just empty, right?

> +	if (!port->iso7816_config)
> +		return -ENOIOCTLCMD;

Why this error value?

> --- a/include/uapi/asm-generic/ioctls.h
> +++ b/include/uapi/asm-generic/ioctls.h
> @@ -66,6 +66,8 @@
>  #ifndef TIOCSRS485
>  #define TIOCSRS485	0x542F
>  #endif
> +#define TIOCGISO7816	0x5430
> +#define TIOCSISO7816	0x5431

Where did you get these numbers from?

thanks,

greg k-h