/*      $NetBSD: ctu.c,v 1.9 2017/05/22 16:59:32 ragge Exp $ */
/*
 * Copyright (c) 1996 Ludd, University of Lule}, Sweden.
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR 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.
 */

/*
 * Standalone device driver for 11/750 Console TU58.
 * It can only handle reads, and doesn't calculate checksum.
 */

#include <sys/param.h>

#include <lib/libsa/stand.h>

#include <machine/mtpr.h>
#include <machine/rsp.h>

#include "vaxstand.h"

static short ctu_cksum(unsigned short *, int);

enum tu_state {
        SC_INIT,
        SC_READY,
        SC_SEND_CMD,
        SC_GET_RESP,
};

volatile struct tu_softc {
        enum    tu_state sc_state;
        char    sc_rsp[15];     /* Should be struct rsb; but don't work */
        u_char  *sc_xfptr;      /* Current char to xfer */
        int     sc_nbytes;      /* Number of bytes to xfer */
        int     sc_xbytes;      /* Number of xfer'd bytes */
        int     sc_bbytes;      /* Number of xfer'd bytes this block */
} tu_sc;

void    ctutintr(void);
void    cturintr(void);

int
ctuopen(struct open_file *f, int adapt, int ctlr, int unit, int part)
{

        tu_sc.sc_state = SC_INIT;

        mtpr(RSP_TYP_INIT, PR_CSTD);
        cturintr();
        tu_sc.sc_state = SC_READY;
        return 0;

}

int
ctustrategy(void *f, int func, daddr_t dblk, size_t size, void *buf, size_t *rsize)
{
        struct rsp *rsp = (struct rsp *)tu_sc.sc_rsp;

        tu_sc.sc_xfptr = buf;
        tu_sc.sc_nbytes = size;
        tu_sc.sc_xbytes = tu_sc.sc_bbytes = 0;

        rsp->rsp_typ = RSP_TYP_COMMAND;
        rsp->rsp_sz = 012;
        rsp->rsp_op = RSP_OP_READ;
        rsp->rsp_mod = 0;
        rsp->rsp_drv = 0;
        rsp->rsp_sw = rsp->rsp_xx1 = rsp->rsp_xx2 = 0;
        rsp->rsp_cnt = tu_sc.sc_nbytes;
        rsp->rsp_blk = dblk;
        rsp->rsp_sum = ctu_cksum((u_short *)rsp, 6);
        tu_sc.sc_state = SC_SEND_CMD;
        while (tu_sc.sc_state != SC_GET_RESP)
                ctutintr();
        while (tu_sc.sc_state != SC_READY)
                cturintr();
        *rsize = size;
        return 0;
}

void
cturintr(void)
{
        int     status;

        while ((mfpr(PR_CSRS) & 0x80) == 0)
                ;

        status = mfpr(PR_CSRD);

        switch (tu_sc.sc_state) {

        case SC_INIT:
                break;

        case SC_GET_RESP:
                if (tu_sc.sc_xbytes == tu_sc.sc_nbytes) {
                        tu_sc.sc_bbytes++;
                        if (tu_sc.sc_bbytes == 146)
                                tu_sc.sc_state = SC_READY;
                        break;
                }
                tu_sc.sc_bbytes++;
                if (tu_sc.sc_bbytes <  3) /* Data header */
                        break;
                if (tu_sc.sc_bbytes == 132) { /* Finished */
                        tu_sc.sc_bbytes = 0;
                        break;
                }
                if (tu_sc.sc_bbytes == 131) /* First checksum */
                        break;
                tu_sc.sc_xfptr[tu_sc.sc_xbytes++] = status;
                break;

        case SC_READY:
        case SC_SEND_CMD:
                break;
        }

}

void
ctutintr(void)
{
        int     c;

        while ((mfpr(PR_CSTS) & 0x80) == 0)
                ;

        c = tu_sc.sc_rsp[tu_sc.sc_xbytes++] & 0xff;
        mtpr(c, PR_CSTD);
        if (tu_sc.sc_xbytes > 13) {
                tu_sc.sc_state = SC_GET_RESP;
                tu_sc.sc_xbytes = 0;
        }
}

short
ctu_cksum(unsigned short *buf, int words)
{
        int i, cksum;

        for (i = cksum = 0; i < words; i++)
                cksum += buf[i];

hej:    if (cksum > 65535) {
                cksum = (cksum & 65535) + (cksum >> 16);
                goto hej;
        }
        return cksum;
}