net: wan: Delete the DLCI / SDLA drivers

The DLCI driver (dlci.c) implements the Frame Relay protocol. However,
we already have another newer and better implementation of Frame Relay
provided by the HDLC_FR driver (hdlc_fr.c).

The DLCI driver's implementation of Frame Relay is used by only one
hardware driver in the kernel - the SDLA driver (sdla.c).

The SDLA driver provides Frame Relay support for the Sangoma S50x devices.
However, the vendor provides their own driver (along with their own
multi-WAN-protocol implementations including Frame Relay), called WANPIPE.
I believe most users of the hardware would use the vendor-provided WANPIPE
driver instead.

(The WANPIPE driver was even once in the kernel, but was deleted in
commit 8db60bc ("[WAN]: Remove broken and unmaintained Sangoma
drivers.") because the vendor no longer updated the in-kernel WANPIPE
driver.)

Cc: Mike McLagan <mike.mclagan@linux.org>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201114150921.685594-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

CREDITS

@@ -2499,15 +2499,6 @@ W: http://www.rdrop.com/users/paulmck/
 D: RCU and variants
 D: rcutorture module
 
-N: Mike McLagan
-E: mike.mclagan@linux.org
-W: http://www.invlogic.com/~mmclagan
-D: DLCI/FRAD drivers for Sangoma SDLAs
-S: Innovative Logic Corp
-S: Post Office Box 1068
-S: Laurel, Maryland 20732
-S: USA
-
 N: Bradley McLean
 E: brad@bradpc.gaylord.com
 D: Device driver hacker

MAINTAINERS

@@ -6905,12 +6905,6 @@ S:	Maintained
 W:	http://floatingpoint.sourceforge.net/emulator/index.html
 F:	arch/x86/math-emu/
 
-FRAME RELAY DLCI/FRAD (Sangoma drivers too)
-L:	netdev@vger.kernel.org
-S:	Orphan
-F:	drivers/net/wan/dlci.c
-F:	drivers/net/wan/sdla.c
-
 FRAMEBUFFER LAYER
 M:	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
 L:	dri-devel@lists.freedesktop.org

arch/arm/configs/ixp4xx_defconfig

@@ -141,7 +141,6 @@ CONFIG_HDLC_CISCO=m
 CONFIG_HDLC_FR=m
 CONFIG_HDLC_PPP=m
 CONFIG_HDLC_X25=m
-CONFIG_DLCI=m
 CONFIG_WAN_ROUTER_DRIVERS=m
 CONFIG_ATM_TCP=m
 # CONFIG_INPUT_KEYBOARD is not set

arch/mips/configs/gpr_defconfig

@@ -228,7 +228,6 @@ CONFIG_FARSYNC=m
 CONFIG_DSCC4=m
 CONFIG_DSCC4_PCISYNC=y
 CONFIG_DSCC4_PCI_RST=y
-CONFIG_DLCI=m
 CONFIG_LAPBETHER=m
 # CONFIG_INPUT_KEYBOARD is not set
 # CONFIG_INPUT_MOUSE is not set

arch/mips/configs/mtx1_defconfig

@@ -378,7 +378,6 @@ CONFIG_FARSYNC=m
 CONFIG_DSCC4=m
 CONFIG_DSCC4_PCISYNC=y
 CONFIG_DSCC4_PCI_RST=y
-CONFIG_DLCI=m
 CONFIG_LAPBETHER=m
 # CONFIG_KEYBOARD_ATKBD is not set
 CONFIG_KEYBOARD_GPIO=y

drivers/net/wan/Kconfig

@@ -321,51 +321,6 @@ config IXP4XX_HSS
 	  Say Y here if you want to use built-in HSS ports
 	  on IXP4xx processor.
 
-config DLCI
-	tristate "Frame Relay DLCI support"
-	help
-	  Support for the Frame Relay protocol.
-
-	  Frame Relay is a fast low-cost way to connect to a remote Internet
-	  access provider or to form a private wide area network. The one
-	  physical line from your box to the local "switch" (i.e. the entry
-	  point to the Frame Relay network, usually at the phone company) can
-	  carry several logical point-to-point connections to other computers
-	  connected to the Frame Relay network. For a general explanation of
-	  the protocol, check out <http://www.mplsforum.org/>.
-
-	  To use frame relay, you need supporting hardware (called FRAD) and
-	  certain programs from the net-tools package as explained in
-	  <file:Documentation/networking/framerelay.rst>.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called dlci.
-
-config DLCI_MAX
-	int "Max DLCI per device"
-	depends on DLCI
-	default "8"
-	help
-	  How many logical point-to-point frame relay connections (the
-	  identifiers of which are called DCLIs) should be handled by each
-	  of your hardware frame relay access devices.
-
-	  Go with the default.
-
-config SDLA
-	tristate "SDLA (Sangoma S502/S508) support"
-	depends on DLCI && ISA
-	help
-	  Driver for the Sangoma S502A, S502E, and S508 Frame Relay Access
-	  Devices.
-
-	  These are multi-protocol cards, but only Frame Relay is supported
-	  by the driver at this time. Please read
-	  <file:Documentation/networking/framerelay.rst>.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called sdla.
-
 # X.25 network drivers
 config LAPBETHER
 	tristate "LAPB over Ethernet driver"

drivers/net/wan/Makefile

@@ -21,8 +21,6 @@ obj-$(CONFIG_FARSYNC)		+= farsync.o
 
 obj-$(CONFIG_LANMEDIA)		+= lmc/
 
-obj-$(CONFIG_DLCI)		+= dlci.o 
-obj-$(CONFIG_SDLA)		+= sdla.o
 obj-$(CONFIG_LAPBETHER)		+= lapbether.o
 obj-$(CONFIG_SBNI)		+= sbni.o
 obj-$(CONFIG_N2)		+= n2.o