/*-
 * Copyright (c) 1998, Michael Smith
 * Copyright (c) 1996, Sujal M. Patel
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 */

/*
 * Machine-independent ISA PnP enumerator implementing a subset of the
 * ISA PnP specification.
 */
#include <stand.h>
#include <string.h>
#include <bootstrap.h>
#include <isapnp.h>

#define inb(x)          (archsw.arch_isainb((x)))
#define outb(x,y)       (archsw.arch_isaoutb((x),(y)))

static void     isapnp_write(int d, int r);
static void     isapnp_send_Initiation_LFSR(void);
static int      isapnp_get_serial(uint8_t *p);
static int      isapnp_isolation_protocol(void);
static void     isapnp_enumerate(void);

/* PnP read data port */
int             isapnp_readport = 0;

#define _PNP_ID_LEN     9

struct pnphandler isapnphandler =
{
    "ISA bus",
    isapnp_enumerate
};

static void
isapnp_write(int d, int r)
{
    outb (_PNP_ADDRESS, d);
    outb (_PNP_WRITE_DATA, r);
}

/*
 * Send Initiation LFSR as described in "Plug and Play ISA Specification",
 * Intel May 94.
 */
static void
isapnp_send_Initiation_LFSR(void)
{
    int cur, i;

    /* Reset the LSFR */
    outb(_PNP_ADDRESS, 0);
    outb(_PNP_ADDRESS, 0); /* yes, we do need it twice! */

    cur = 0x6a;
    outb(_PNP_ADDRESS, cur);

    for (i = 1; i < 32; i++) {
        cur = (cur >> 1) | (((cur ^ (cur >> 1)) << 7) & 0xff);
        outb(_PNP_ADDRESS, cur);
    }
}

/*
 * Get the device's serial number.  Returns 1 if the serial is valid.
 */
static int
isapnp_get_serial(uint8_t *data)
{
    int         i, bit, valid = 0, sum = 0x6a;

    bzero(data, _PNP_ID_LEN);
    outb(_PNP_ADDRESS, SERIAL_ISOLATION);
    for (i = 0; i < 72; i++) {
        bit = inb(isapnp_readport) == 0x55;
        delay(250);     /* Delay 250 usec */

        /* Can't Short Circuit the next evaluation, so 'and' is last */
        bit = (inb(isapnp_readport) == 0xaa) && bit;
        delay(250);     /* Delay 250 usec */

        valid = valid || bit;

        if (i < 64)
            sum = (sum >> 1) |
                (((sum ^ (sum >> 1) ^ bit) << 7) & 0xff);

        data[i / 8] = (data[i / 8] >> 1) | (bit ? 0x80 : 0);
    }

    valid = valid && (data[8] == sum);

    return valid;
}

/*
 * Fills the buffer with resource info from the device.
 * Returns nonzero if the device fails to report
 */
static int
isapnp_get_resource_info(uint8_t *buffer, int len)
{
    int         i, j;
    u_char      temp;

    for (i = 0; i < len; i++) {
        outb(_PNP_ADDRESS, STATUS);
        for (j = 0; j < 100; j++) {
            if ((inb(isapnp_readport)) & 0x1)
                break;
            delay(1);
        }
        if (j == 100) {
            printf("PnP device failed to report resource data\n");
            return(1);
        }
        outb(_PNP_ADDRESS, RESOURCE_DATA);
        temp = inb(isapnp_readport);
        if (buffer != NULL)
            buffer[i] = temp;
    }
    return(0);
}

/*
 * Scan Resource Data for useful information.
 *
 * We scan the resource data for compatible device IDs and
 * identifier strings; we only take the first identifier string
 * and assume it's for the card as a whole.
 *
 * Returns 0 if the scan completed OK, nonzero on error.
 */
static int
isapnp_scan_resdata(struct pnpinfo *pi)
{
    u_char      tag, resinfo[8];
    u_int       limit;
    size_t      large_len;
    u_char      *str;

    limit = 1000;
    while ((limit-- > 0) && !isapnp_get_resource_info(&tag, 1)) {
        if (PNP_RES_TYPE(tag) == 0) {
            /* Small resource */
            switch (PNP_SRES_NUM(tag)) {

                case COMP_DEVICE_ID:
                    /* Got a compatible device id resource */
                    if (isapnp_get_resource_info(resinfo, PNP_SRES_LEN(tag)))
                        return(1);
                    pnp_addident(pi, pnp_eisaformat(resinfo));

                case END_TAG:
                    return(0);
                    break;

                default:
                    /* Skip this resource */
                    if (isapnp_get_resource_info(NULL, PNP_SRES_LEN(tag)))
                        return(1);
                    break;
            }
        } else {
            /* Large resource */
            if (isapnp_get_resource_info(resinfo, 2))
                return(1);

            large_len = resinfo[1];
            large_len = (large_len << 8) + resinfo[0];

            switch(PNP_LRES_NUM(tag)) {

            case ID_STRING_ANSI:
                str = malloc(large_len + 1);
                if (isapnp_get_resource_info(str, (ssize_t)large_len)) {
                    free(str);
                    return(1);
                }
                str[large_len] = 0;
                if (pi->pi_desc == NULL) {
                    pi->pi_desc = (char *)str;
                } else {
                    free(str);
                }
                break;
                
            default:
                /* Large resource, skip it */
                if (isapnp_get_resource_info(NULL, (ssize_t)large_len))
                    return(1);
            }
        }
    }
    return(1);
}

/*
 * Run the isolation protocol. Upon exiting, all cards are aware that
 * they should use isapnp_readport as the READ_DATA port.
 */
static int
isapnp_isolation_protocol(void)
{
    int                 csn;
    struct pnpinfo      *pi;
    uint8_t             cardid[_PNP_ID_LEN];
    int                 ndevs;

    isapnp_send_Initiation_LFSR();
    ndevs = 0;
    
    isapnp_write(CONFIG_CONTROL, 0x04); /* Reset CSN for All Cards */

    for (csn = 1; ; csn++) {
        /* Wake up cards without a CSN (ie. all of them) */
        isapnp_write(WAKE, 0);
        isapnp_write(SET_RD_DATA, (isapnp_readport >> 2));
        outb(_PNP_ADDRESS, SERIAL_ISOLATION);
        delay(1000);    /* Delay 1 msec */

        if (isapnp_get_serial(cardid)) {
            isapnp_write(SET_CSN, csn);
            pi = pnp_allocinfo();
            ndevs++;
            pnp_addident(pi, pnp_eisaformat(cardid));
            /* scan the card obtaining all the identifiers it holds */
            if (isapnp_scan_resdata(pi)) {
                pnp_freeinfo(pi);       /* error getting data, ignore */
            } else {
                pnp_addinfo(pi);
            }
        } else {
            break;
        }
    }
    /* Move all cards to wait-for-key state */
    while (--csn > 0) {
        isapnp_send_Initiation_LFSR();
        isapnp_write(WAKE, csn);
        isapnp_write(CONFIG_CONTROL, 0x02);
        delay(1000); /* XXX is it really necessary ? */
        csn--;
    }
    return(ndevs);
}

/*
 * Locate ISA-PnP devices and populate the supplied list.
 */
static void
isapnp_enumerate(void) 
{
    int         pnp_rd_port;
    
    /* Check for I/O port access */
    if ((archsw.arch_isainb == NULL) || (archsw.arch_isaoutb == NULL))
        return;

    /* 
     * Validate a possibly-suggested read port value.  If the autoscan failed
     * last time, this will return us to autoscan mode again.
     */
    if ((isapnp_readport > 0) &&
        (((isapnp_readport < 0x203) ||
          (isapnp_readport > 0x3ff) ||
          (isapnp_readport & 0x3) != 0x3)))
         /* invalid, go look for ourselves */
        isapnp_readport = 0;

    if (isapnp_readport < 0) {
        /* someone is telling us there is no ISA in the system */
        return;

    } else if (isapnp_readport > 0) {
        /* Someone has told us where the port is/should be, or we found one last time */
        isapnp_isolation_protocol();

    } else {
        /* No clues, look for it ourselves */
        for (pnp_rd_port = 0x80; pnp_rd_port < 0xff; pnp_rd_port += 0x10) {
            /* Look for something, quit when we find it */
            isapnp_readport = (pnp_rd_port << 2) | 0x3;
            if (isapnp_isolation_protocol() > 0)
                break;
        }
    }
}