\ *****************************************************************************
\ * Copyright (c) 2016 IBM Corporation
\ * All rights reserved.
\ * This program and the accompanying materials
\ * are made available under the terms of the BSD License
\ * which accompanies this distribution, and is available at
\ * http://www.opensource.org/licenses/bsd-license.php
\ *
\ * Contributors:
\ *     IBM Corporation - initial implementation
\ ****************************************************************************/

s" serial" device-type

FALSE VALUE initialized?

virtio-setup-vd VALUE virtiodev

\ Quiescence the virtqueue of this device so that no more background
\ transactions can be pending.
: shutdown  ( -- )
    initialized? IF
        virtiodev virtio-serial-shutdown
        FALSE to initialized?
        0 to virtiodev
    THEN
;

: virtio-serial-term-emit
    virtiodev SWAP virtio-serial-putchar
;

: virtio-serial-term-key?  virtiodev virtio-serial-haschar ;
: virtio-serial-term-key   BEGIN virtio-serial-term-key? UNTIL virtiodev virtio-serial-getchar ;

: virtio-serial-close-stdout s" stdout" get-chosen IF decode-int nip nip close-dev THEN ;

\ Basic device initialization - which has only to be done once
: init  ( -- )
virtiodev virtio-serial-init drop
    TRUE to initialized?
    \ Linux closes stdin at some point in prom_init(). This internally triggers a
    \ quiesce in SLOF. We must ensure stdout gets closed as well otherwise the
    \ device cannot be reset properly and the boot will hang.
    ['] virtio-serial-close-stdout add-quiesce-xt
;

0 VALUE open-count

\ Standard node "open" function
: open  ( -- okay? )
    open-count 0= IF
        open IF initialized? 0= IF init THEN
            true
        ELSE false exit
        THEN
    ELSE true THEN
    open-count 1 + to open-count
;

: close
    open-count 0> IF
        open-count 1 - dup to open-count
        0= IF shutdown THEN
    THEN
    close
;

: write ( addr len -- actual )
    virtiodev 0= IF nip EXIT THEN
    tuck
    0 ?DO
        dup c@ virtiodev SWAP virtio-serial-putchar
        1 +
    LOOP
    drop
;

: read ( addr len -- actual )
    0= IF drop 0 EXIT THEN
    virtiodev 0= IF nip EXIT THEN
    virtiodev virtio-serial-haschar 0= IF 0 swap c! -2 EXIT THEN
    virtiodev virtio-serial-getchar swap c! 1
;

: setup-alias
    " vsterm" find-alias 0= IF
        " vsterm" get-node node>path set-alias
    ELSE drop THEN
;
setup-alias