net: atm: remove the ambassador driver

The driver for ATM Ambassador devices spews build warnings on
microblaze. The virt_to_bus() calls discard the volatile keyword.
The right thing to do would be to migrate this driver to a modern
DMA API but it seems unlikely anyone is actually using it.
There had been no fixes or functional changes here since
the git era begun.

In fact it sounds like the FW loading was broken from 2008
'til 2012 - see commit fcdc90b ("atm: forever loop loading
ambassador firmware").

Let's remove this driver, there isn't much changing in the APIs,
if users come forward we can apologize and revert.

Link: https://lore.kernel.org/all/20220321144013.440d7fc0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/mips/configs/gpr_defconfig

@@ -182,7 +182,6 @@ CONFIG_ATM_FIRESTREAM=m
 CONFIG_ATM_ZATM=m
 CONFIG_ATM_NICSTAR=m
 CONFIG_ATM_IDT77252=m
-CONFIG_ATM_AMBASSADOR=m
 CONFIG_ATM_HORIZON=m
 CONFIG_ATM_IA=m
 CONFIG_ATM_FORE200E=m

arch/mips/configs/mtx1_defconfig

@@ -259,7 +259,6 @@ CONFIG_ATM_FIRESTREAM=m
 CONFIG_ATM_ZATM=m
 CONFIG_ATM_NICSTAR=m
 CONFIG_ATM_IDT77252=m
-CONFIG_ATM_AMBASSADOR=m
 CONFIG_ATM_HORIZON=m
 CONFIG_ATM_IA=m
 CONFIG_ATM_FORE200E=m

drivers/atm/Kconfig

@@ -244,31 +244,6 @@ config ATM_IDT77252_USE_SUNI
 	depends on ATM_IDT77252
 	default y
 
-config ATM_AMBASSADOR
-	tristate "Madge Ambassador (Collage PCI 155 Server)"
-	depends on PCI && VIRT_TO_BUS
-	select BITREVERSE
-	help
-	  This is a driver for ATMizer based ATM card produced by Madge
-	  Networks Ltd. Say Y (or M to compile as a module named ambassador)
-	  here if you have one of these cards.
-
-config ATM_AMBASSADOR_DEBUG
-	bool "Enable debugging messages"
-	depends on ATM_AMBASSADOR
-	help
-	  Somewhat useful debugging messages are available. The choice of
-	  messages is controlled by a bitmap.  This may be specified as a
-	  module argument (kernel command line argument as well?), changed
-	  dynamically using an ioctl (not yet) or changed by sending the
-	  string "Dxxxx" to VCI 1023 (where x is a hex digit).  See the file
-	  <file:drivers/atm/ambassador.h> for the meanings of the bits in the
-	  mask.
-
-	  When active, these messages can have a significant impact on the
-	  speed of the driver, and the size of your syslog files! When
-	  inactive, they will have only a modest impact on performance.
-
 config ATM_HORIZON
 	tristate "Madge Horizon [Ultra] (Collage PCI 25 and Collage PCI 155 Client)"
 	depends on PCI && VIRT_TO_BUS

drivers/atm/Makefile

@@ -7,7 +7,6 @@ fore_200e-y	:= fore200e.o
 
 obj-$(CONFIG_ATM_ZATM)		+= zatm.o uPD98402.o
 obj-$(CONFIG_ATM_NICSTAR)	+= nicstar.o
-obj-$(CONFIG_ATM_AMBASSADOR)	+= ambassador.o
 obj-$(CONFIG_ATM_HORIZON)	+= horizon.o
 obj-$(CONFIG_ATM_IA)		+= iphase.o suni.o
 obj-$(CONFIG_ATM_FORE200E)	+= fore_200e.o