net-caif-driver: add CAIF serial driver (ldisc)

Add CAIF Serial driver. This driver is implemented as a line discipline.

caif_serial uses the following module parameters:
ser_use_stx - specifies if STart of frame eXtension is in use.
ser_loop    - sets the interface in loopback mode.

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -2837,6 +2837,8 @@ source "drivers/ieee802154/Kconfig"
 
 source "drivers/s390/net/Kconfig"
 
+source "drivers/net/caif/Kconfig"
+
 config XEN_NETDEV_FRONTEND
 	tristate "Xen network device frontend driver"
 	depends on XEN

drivers/net/Makefile

@@ -290,5 +290,6 @@ obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
 obj-$(CONFIG_SFC) += sfc/
 
 obj-$(CONFIG_WIMAX) += wimax/
+obj-$(CONFIG_CAIF) += caif/
 
 obj-$(CONFIG_OCTEON_MGMT_ETHERNET) += octeon/

drivers/net/caif/Kconfig

@@ -0,0 +1,17 @@
+#
+# CAIF physical drivers
+#
+
+if CAIF
+
+comment "CAIF transport drivers"
+
+config CAIF_TTY
+	tristate "CAIF TTY transport driver"
+	default n
+	---help---
+	The CAIF TTY transport driver is a Line Discipline (ldisc)
+	identified as N_CAIF. When this ldisc is opened from user space
+	it will redirect the TTY's traffic into the CAIF stack.
+
+endif # CAIF

drivers/net/caif/Makefile

@@ -0,0 +1,12 @@
+ifeq ($(CONFIG_CAIF_DEBUG),1)
+CAIF_DBG_FLAGS := -DDEBUG
+endif
+
+KBUILD_EXTRA_SYMBOLS=net/caif/Module.symvers
+
+ccflags-y := $(CAIF_FLAGS) $(CAIF_DBG_FLAGS)
+clean-dirs:= .tmp_versions
+clean-files:= Module.symvers modules.order *.cmd *~ \
+
+# Serial interface
+obj-$(CONFIG_CAIF_TTY) += caif_serial.o