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Date:   Thu, 12 Jul 2018 17:02:29 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Ludovic Desroches <ludovic.desroches@microchip.com>
Cc:     linux-serial@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, jslaby@suse.com,
        arnd@arndb.de, richard.genoud@gmail.com,
        nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] tty/serial_core: add ISO7816 infrastructure
Message-ID: <20180712150229.GE22502@kroah.com>
References: <20180711131638.12622-1-ludovic.desroches@microchip.com>
 <20180711131638.12622-2-ludovic.desroches@microchip.com>
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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(+)
> 
> 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;
> +	spin_unlock_irqrestore(&port->lock, flags);
> +
> +	if (copy_to_user(iso7816, &aux, sizeof(aux)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
> +static int uart_set_iso7816_config(struct uart_port *port,
> +				   struct serial_iso7816 __user *iso7816_user)
> +{
> +	struct serial_iso7816 iso7816;
> +	int ret;
> +	unsigned long flags;
> +
> +	if (!port->iso7816_config)
> +		return -ENOIOCTLCMD;
> +
> +	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
> +		return -EFAULT;
> +
> +	spin_lock_irqsave(&port->lock, flags);
> +	ret = port->iso7816_config(port, &iso7816);
> +	spin_unlock_irqrestore(&port->lock, flags);
> +	if (ret)
> +		return ret;
> +
> +	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>  /*
>   * Called via sys_ioctl.  We can use spin_lock_irq() here.
>   */
> @@ -1385,6 +1426,14 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
>  	case TIOCSRS485:
>  		ret = uart_set_rs485_config(uport, uarg);
>  		break;
> +
> +	case TIOCSISO7816:
> +		ret = uart_set_iso7816_config(state->uart_port, uarg);
> +		break;
> +
> +	case TIOCGISO7816:
> +		ret = uart_get_iso7816_config(state->uart_port, uarg);
> +		break;
>  	default:
>  		if (uport->ops->ioctl)
>  			ret = uport->ops->ioctl(uport, cmd, arg);
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 06ea4eeb09ab..d6e7747ffd46 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -137,6 +137,8 @@ struct uart_port {
>  	void			(*handle_break)(struct uart_port *);
>  	int			(*rs485_config)(struct uart_port *,
>  						struct serial_rs485 *rs485);
> +	int			(*iso7816_config)(struct uart_port *,
> +						  struct serial_iso7816 *iso7816);
>  	unsigned int		irq;			/* irq number */
>  	unsigned long		irqflags;		/* irq flags  */
>  	unsigned int		uartclk;		/* base uart clock */
> @@ -253,6 +255,7 @@ struct uart_port {
>  	struct attribute_group	*attr_group;		/* port specific attributes */
>  	const struct attribute_group **tty_groups;	/* all attributes (serial core use only) */
>  	struct serial_rs485     rs485;
> +	struct serial_iso7816   iso7816;
>  	void			*private_data;		/* generic platform data pointer */
>  };
>  
> diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
> index 040651735662..0e5c79726c2d 100644
> --- 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
>  #define TIOCGPTN	_IOR('T', 0x30, unsigned int) /* Get Pty Number (of pty-mux device) */
>  #define TIOCSPTLCK	_IOW('T', 0x31, int)  /* Lock/unlock Pty */
>  #define TIOCGDEV	_IOR('T', 0x32, unsigned int) /* Get primary device node of /dev/console */
> diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
> index 3fdd0dee8b41..93eb3c496ff1 100644
> --- a/include/uapi/linux/serial.h
> +++ b/include/uapi/linux/serial.h
> @@ -132,4 +132,21 @@ struct serial_rs485 {
>  					   are a royal PITA .. */
>  };
>  
> +/*
> + * Serial interface for controlling ISO7816 settings on chips with suitable
> + * support. Set with TIOCSISO7816 and get with TIOCGISO7816 if supported by
> + * your platform.
> + */
> +struct serial_iso7816 {
> +	__u32	flags;			/* ISO7816 feature flags */
> +#define SER_ISO7816_ENABLED		(1 << 0)
> +#define SER_ISO7816_T_PARAM		(0x0f << 4)
> +#define SER_ISO7816_T(t)		(((t) & 0x0f) << 4)
> +	__u32	tg;
> +	__u32	sc_fi;
> +	__u32	sc_di;
> +	__u32	clk;
> +	__u32	reserved[5];

You need to verify that reserved[] is all set to 0, otherwise people
will put crud in there and you can never use it for anything in the
future.

thanks,

greg k-h