zs: move to the serial subsystem

This is a reimplementation of the zs driver for the serial subsystem.  Any
resemblance to the old driver is purely coincidential.  ;-) I do hope I got
the handling of modem lines right -- better do not tackle me about the
issue unless you feel too good...

Any users of the old driver: please note the numbers of the serial lines
have now been swapped, i.e.  ttyS0 <-> ttyS1 and ttyS2 <-> ttyS3.  It has
to do with the modem lines mentioned above; basically the port A in a given
chip has to be initialised before the port B if you want to use the latter
as the serial console (which is usually the case), as operations on modem
lines of the serial line associated with the port B access both ports (see
the comment at the top of the driver for the details of wiring used).
Please update your scripts.

This is also the reason each SCC now requests an IRQ once only (as seen in
"/proc/interrupts") -- the handler takes care of both ports at once as the
line associated with the port B has to take status update interrupts from
both ports (and yet the line of the port A takes its own for itself too).
The old driver never got it right...

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 7fa413ddccf5..18f629706448 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -486,6 +486,36 @@ config SERIAL_DZ_CONSOLE
 
           If unsure, say Y.
 
+config SERIAL_ZS
+        tristate "DECstation Z85C30 serial support"
+        depends on MACH_DECSTATION
+        select SERIAL_CORE
+        default y
+        ---help---
+          Support for the Zilog 85C350 serial communications controller used
+          for serial ports in newer DECstation systems.  These include the
+          DECsystem 5900 and all models of the DECstation and DECsystem 5000
+          systems except from model 200.
+
+          If unsure, say Y.  To compile this driver as a module, choose M here:
+          the module will be called zs.
+
+config SERIAL_ZS_CONSOLE
+        bool "Support for console on a DECstation Z85C30 serial port"
+        depends on SERIAL_ZS=y
+        select SERIAL_CORE_CONSOLE
+        default y
+        ---help---
+          If you say Y here, it will be possible to use a serial port as the
+          system console (the system console is the device which receives all
+          kernel messages and warnings and which allows logins in single user
+          mode).
+
+          Note that the firmware uses ttyS1 as the serial console on the
+          Maxine and ttyS3 on the others using this driver.
+
+          If unsure, say Y.
+
 config SERIAL_21285
         tristate "DC21285 serial port support"
         depends on ARM && FOOTBRIDGE