#lang scheme/base
(require
 "tethered.ss"
 scheme/system)

(provide
 comm-uart)




;; serial port

(define stty
  (let ((fmt #f)
        (fmts
         '(("Linux"         . "stty -F ~a ~a raw min 1 -echo")
           ("CYGWIN_NT-5.1" . "stty -F ~a ~a min 1 -echo ixon -icanon pass8")
           ("windows"       . "mode ~a: baud=~a parity=n data=8 stop=1 xon=off dtr=off rts=off"))))
    (lambda (name baud)
      (unless fmt
        ;; Fixme: do autodetect using 'uname' or something..
        (set! fmt (cdr (assoc "Linux" fmts))))
      (system (format fmt name baud)))))


(define (comm-uart name baud)

  (define (standard-serial-port)
    (let-values
        (((i o)
          (open-input-output-file name #:exists 'append)))
      (file-stream-buffer-mode o 'none)
      (stty name baud)
      
      (comm-in    (lambda () (d: "in ~x\n"
                                     ;; (read-byte-timeout i 3)
                                     (read-byte i)
                                       )))
      (comm-out   (lambda (b) (write-byte (d: "out ~x\n" b) o)))
      (comm-close (lambda () (close-input-port i) (close-output-port o)))

      ))

  

  ;; FIXME: re-enable pk2 support through external console interface.
  
  ;; '(define (pk2-serial-port)
  ;;   (define (stop)
  ;;     (uart-stop) (target-off) (msleep 300))
  ;;   (define (start)
  ;;     (target-on)
  ;;     (uart-start baud)
  ;;     (comm-in uart-read)
  ;;     (comm-out uart-write)
  ;;     (comm-close
  ;;      (lambda () (stop) (pk2-close)))
  ;;     (comm-reset
  ;;      (lambda ()
  ;;        (printf "PK2: target cold reset.\n")
  ;;        (stop)     ;; don't pk2-close!
  ;;        (sleep 1)  ;; this ensures proper shutdown.  FIXME: fix thread sync!
  ;;        (start)))

  ;;     ;; Hack to start up communication.  For some reason, the first
  ;;     ;; ACK request doesn't seem to get through.  It does work when
  ;;     ;; proper PK2 shutdown is disabled (EXIT_UART_MODE), but then
  ;;     ;; programming doesn't work on next try.  This is probably a
  ;;     ;; glitch on the TX line...
  ;;     (begin
  ;;       (uart-write 1 6)
  ;;       (msleep 100)
  ;;       (let ((ret (uart-try-read)))
  ;;         ;; (printf "usart-start: ~a\n" ret)
  ;;         (unless ret
  ;;           (printf "uart-start hack\n"))))
  ;;     )
  ;;   (pk2-boot)
  ;;   (start))

  

  ((comm-close))


  ;; '(if (equal? "pk2" name)
  ;;      (pk2-serial-port)
  ;;      (standard-serial-port))
  
  (standard-serial-port)


  )