/*      $NetBSD: weaselreg.h,v 1.8 2022/04/11 20:57:38 andvar Exp $     */

/*-
 * Copyright (c) 2000 Zembu Labs, Inc.
 * All rights reserved.
 *
 * Author: Jason R. Thorpe <thorpej@zembu.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Zembu Labs, Inc.
 * 4. Neither the name of Zembu Labs nor the names of its employees may
 *    be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY ZEMBU LABS, INC. ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAR-
 * RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DIS-
 * CLAIMED.  IN NO EVENT SHALL ZEMBU LABS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Register and firmware communication definitions for the
 * Middle Digital, Inc. PC-Weasel serial console board.
 */

/*
 * Current versions of the PC-Weasel emulate a Monochrome Display
 * Adapter.  The framebuffer is at the standard ISA framebuffer
 * location (0xb0000).  At the end of the viewable framebuffer area
 * is a control register space.
 */

#define WEASEL_WDT_SEMAPHORE            0x0fa0

#define WEASEL_CONFIG_BLOCK             0x0fa1

#define WEASEL_WDT_TICKLE               0x0fa2

#define WEASEL_MISC_COMMAND             0x0fcd

#define WEASEL_MISC_RESPONSE            0x0fce

/*
 * Layout of the PC-Weasel configuration block.  This is taken
 * more or less right out of the PC-Weasel manual, page 52.
 */
struct weasel_config_block {
        u_int8_t        cfg_version;    /* configuration version */

#define CFG_VERSION_1_0         0x01
#define CFG_VERSION_1_1         0x02

        u_int8_t        weasel_attn;    /* Weasel attention character */
        u_int8_t        debug;          /* debug level */
        u_int8_t        reset_pc_on_boot;/* reset PC on Weasel boot */
        u_int8_t        duart_baud;     /* baud rate of DUART */
        u_int8_t        duart_parity;   /* 0 none, 1 even, 2 odd */
        u_int8_t        duart_bits;     /* 7 or 8 */

        /*
         * Unfortunately, between cfg_version 1 and 2, the semantics
         * of this variable changed.
         *
         *      cfg_version 1:
         *
         *              0 == always emulate
         *              1 == autoswitch
         *
         *      cfg_version 2:
         *
         *              0 == always emulate
         *              1 == always serial
         *              2 == autoswitch
         */
        u_int8_t        enable_duart_switching;
        u_int8_t        wdt_allow;      /* 0 disable, 1 allow */
        u_int16_t       wdt_msec;       /* watchdog timer period */
        u_int8_t        duart_flow;     /* 1 rts/cts, 0 none */
        u_int8_t        break_passthru; /* BREAK is passed through */
        u_int8_t        obsolete[30];   /* reserved for future use */
        u_int8_t        cksum;          /* arithmetic sum -> reserved */
} __packed;

/*
 * Commands that can be written to the MISC_COMMAND register.
 */

#define OS_READY        0x00            /* ready for commands */

#define OS_UART_CLEAR   0x01            /* clear response for OS_UART_QUERY */

#define OS_UART_QUERY   0x02            /* query Weasel UART setting */
#define UART_QUERY_DIS  0x00            /* UART is disabled */
#define UART_QUERY_3f8  0x01            /* UART at 0x3f8 */
#define UART_QUERY_2F8  0x02            /* UART at 0x2f8 */
#define UART_QUERY_3e8  0x03            /* UART at 0x3e8 */
#define UART_QUERY_2e8  0x04            /* UART at 0x2e8 */

#define OS_CONFIG_COPY  0x03            /* copy config to offscreen space */
#define OS_WDT_QUERY    0x04            /* query watchdog state. 0=off 1=on */

#define OS_NOP          0x07

/*
 * The watchdog timer on the PC-Weasel is enabled/disabled (it's a toggle)
 * using the WDT_SEMAPHORE register in the offscreen area.  The semaphore
 * is also used to service the watchdog.
 *
 * To toggle the watchdog:
 *
 *      for (new_state = old_state; new_state == old_state;) {
 *              WDT_SEMAPHORE = 0x22;
 *              delay(1500);
 *              if (WDT_SEMAPHORE == 0xea) {
 *                      WDT_SEMAPHORE = 0x2f;
 *                      delay(1500);
 *                      if (WDT_SEMAPHORE == 0xae) {
 *                              WDT_SEMAPHORE = 0x37;
 *                              delay(1500);
 *                              new_state = WDT_SEMAPHORE;
 *                      }
 *              }
 *      }
 *
 * To service the watchdog when armed:
 *
 *      tmp = WDT_SEMPAPHORE;
 *      WDT_SEMAPHORE ~= tmp;
 */
#define WDT_ATTENTION   0x22    /* get the attention of the WDT state engine */
#define WDT_OK          0xae    /* we get back an acknowledgement */
#define WDT_ENABLE      0xf1    /* the command to arm to watchdog. */
#define WDT_DISABLE     0xf4    /* the command to disarm the watchdog. */