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

[Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>]

From: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
[ludovic.desroches@xxxxxxxxxxxxx: squash and rebase, removal of gpios, checkpatch fixes]
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
---
 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];
+};
+
 #endif /* _UAPI_LINUX_SERIAL_H */
-- 
2.12.2