/*      $NetBSD: mca_machdep.c,v 1.6 2024/07/02 06:07:12 rin Exp $      */

/*-
 * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
 * Copyright (c) 1996-1999 Scott D. Telford.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Scott Telford <s.telford@ed.ac.uk> and Jaromir Dolecek
 * <jdolecek@NetBSD.org>.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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-specific functions for MCA autoconfiguration.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mca_machdep.c,v 1.6 2024/07/02 06:07:12 rin Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/systm.h>
#include <sys/syslog.h>
#include <sys/time.h>
#include <sys/kernel.h>

#include <powerpc/pio.h>
#define _POWERPC_BUS_DMA_PRIVATE
#include <sys/bus.h>

#include <dev/mca/mcavar.h>
#include <dev/mca/mcareg.h>

#include "opt_mcaverbose.h"

#ifdef UNUSED
static void     _mca_bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t,
                    bus_addr_t, bus_size_t, int);
#endif

/*
 * For now, we use MCA DMA to 0-16M always. Some IBM PS/2 have 32bit MCA bus,
 * but majority of them have 24bit only.
 */
#define MCA_DMA_BOUNCE_THRESHOLD        (16 * 1024 * 1024)

/* Updated in mca_busprobe() if appropriate. */
int MCA_system = 0;

//static bus_space_handle_t dmaiot, dmacmdh, dmaexech;

#define MAX_SLAVE_CHANNELS      8
#define MAX_DMA_CHANNELS        16

#define INIT_DMA_CHN_BITMASK()  (0xFFFFFFFF << (32 - MAX_DMA_CHANS))
#define INIT_SLAVE_CHN_BITMASK(slaves)  (0xFFFFFFFF << (32 - (slaves))

#define DMA_AVAIL(chn, bitmask) ((bitmask) & (1 << (31 - (chn))))
#define DMA_ALLOC(chn, bitmask) ((bitmask) &= ~(1 << (31 - (chn))))
#define DMA_FREE(chn, bitmask)  ((bitmask) |= (1 << (31 - (chn))))

/*
 * MCA DMA controller commands. The exact sense of individual bits
 * are from Tymm Twillman <tymm@computer.org>, who worked on Linux MCA DMA
 * support.
 */
#define DMACMD_SET_IO           0x00    /* set port (16bit) for i/o transfer */
#define DMACMD_SET_ADDR         0x20    /* set addr (24bit) for i/o transfer */
#define DMACMD_GET_ADDR         0x30    /* get addr (24bit) for i/o transfer */
#define DMACMD_SET_CNT          0x40    /* set memory size for DMA (16b) */
#define DMACMD_GET_CNT          0x50    /* get count of remaining bytes in DMA*/
#define DMACMD_GET_STATUS       0x60    /* ?? */
#define DMACMD_SET_MODE         0x70    /* set DMA mode */
# define DMACMD_MODE_XFER       0x04    /* do transfer, read by default */
# define DMACMD_MODE_READ       0x08    /* read transfer */
# define DMACMD_MODE_WRITE      0x00    /* write transfer */
# define DMACMD_MODE_IOPORT     0x01    /* DMA from/to IO register */
# define DMACMD_MODE_16BIT      0x40    /* 16bit transfers (default 8bit) */
#define DMACMD_SET_ARBUS        0x80    /* ?? */
#define DMACMD_MASK             0x90    /* command mask */
#define DMACMD_RESET_MASK       0xA0    /* reset */
#define DMACMD_MASTER_CLEAR     0xD0    /* ?? */

const struct evcnt *
mca_intr_evcnt(mca_chipset_tag_t ic, int irq)
{
        /* XXX for now, no evcnt parent reported */
        return NULL;
}

/*
 * Map the MCA DMA controller registers.
 */
void
mca_attach_hook(device_t parent, device_t self, struct mcabus_attach_args *mba)
{
#if 0
        dmaiot = mba->mba_iot;

        if (bus_space_map(dmaiot, DMA_CMD, 1, 0, &dmacmdh)
            || bus_space_map(dmaiot, DMA_EXEC, 1, 0, &dmaexech))
                panic("mca: couldn't map DMA registers");
#endif
}

/*
 * Read value of MCA POS register "reg" in slot "slot".
 */

int
mca_conf_read(mca_chipset_tag_t mc, int slot, int reg)
{
        int     data;

        slot &= 15;     /* slot must be in range 0-15 */
        data = inb(RS6000_BUS_SPACE_IO + MCA_POS_REG(reg) + (slot<<16));
        return data;
}


/*
 * Write "data" to MCA POS register "reg" in slot "slot".
 */

void
mca_conf_write(mca_chipset_tag_t mc, int slot, int reg, int data)
{
        slot &= 15;     /* slot must be in range 0-15 */
        outb(RS6000_BUS_SPACE_IO + MCA_POS_REG(reg) + (slot<<16), data);
}


void *
mca_intr_establish(mca_chipset_tag_t mc, mca_intr_handle_t ih,
    int level, int (*func)(void *), void *arg)
{
        if (ih == 0 || ih >= ICU_LEN)
                panic("mca_intr_establish: bogus handle 0x%x", ih);

        /* MCA interrupts are always level-triggered */
        return intr_establish(ih, IST_LEVEL, level, func, arg);
}

void
mca_intr_disestablish(mca_chipset_tag_t mc, void *cookie)
{
        intr_disestablish(cookie);
}
        

/*
 * GCC 12 blames pointer reference to 0-th page, [0, 0xfff].
 * XXX map to higher address as done for, e.g., arm by devmap?
 */
#pragma GCC diagnostic push                                     /* XXX { */
#pragma GCC diagnostic ignored "-Warray-bounds"

/*
 * Handle a NMI.
 * return true to panic system, false to ignore.
 */
int
mca_nmi(void)
{
        /*
        * PS/2 MCA devices can generate NMIs - we can find out which
        * slot generated it from the POS registers.
        */
 
        int     slot, mcanmi=0;

        /* if there is no MCA bus, call x86_nmi() */
        if (!MCA_system)
                goto out;

        /* ensure motherboard setup is disabled */
        outb(MCA_MB_SETUP_REG, 0xff);

        /* find if an MCA slot has the CHCK bit asserted (low) in POS 5 */
        for(slot=0; slot<MCA_MAX_SLOTS; slot++) {
                outb(MCA_ADAP_SETUP_REG, slot | MCA_ADAP_SET);
                if ((inb(MCA_POS_REG(5)) & MCA_POS5_CHCK) == 0) {
                        mcanmi = 1;
                        /* find if CHCK status is available in POS 6/7 */
                        if((inb(MCA_POS_REG(5)) & MCA_POS5_CHCK_STAT) == 0)
                                log(LOG_CRIT, "MCA NMI: slot %d, POS6=0x%02x, POS7=0x%02x\n",
                                        slot+1, inb(MCA_POS_REG(6)),
                                                inb(MCA_POS_REG(7)));
                        else
                                log(LOG_CRIT, "MCA NMI: slot %d\n", slot+1);
                }
        }
        outb(MCA_ADAP_SETUP_REG, 0);

   out:
        if (!mcanmi) {
                /* no CHCK bits asserted, assume ISA NMI */
                //return (x86_nmi());
                return 0;
        } else
                return(0);
}

/*
 * Realistically, we should probe for the presence of an MCA bus here, and
 * return a reasonable value.  However, this port is never expected to run
 * on anything other than MCA, so rather than write a bunch of complex code
 * to find that we indeed have a bus, lets just assume we do.
 */
void
mca_busprobe(void)
{
        MCA_system = 1;
}

#define PORT_DISKLED    0x92
#define DISKLED_ON      0x40

/*
 * Light disk busy LED on IBM PS/2.
 */
void
mca_disk_busy(void)
{
        outb(PORT_DISKLED, inb(PORT_DISKLED) | DISKLED_ON);
}

/*
 * Turn off disk LED on IBM PS/2.
 */
void
mca_disk_unbusy(void)
{
        outb(PORT_DISKLED, inb(PORT_DISKLED) & ~DISKLED_ON);
}

#pragma GCC diagnostic pop                                      /* XXX } */

/*
 * -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 * MCA DMA specific stuff. We use ISA routines for bulk of the work,
 * since MCA shares much of the charasteristics with it. We just hook
 * the DMA channel initialization and kick MCA DMA controller appropriately.
 * -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 */

#ifdef NOTYET
/*
 * Synchronize a MCA DMA map.
 */
static void
_mca_bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        struct rs6000_dma_cookie *cookie;
        bus_addr_t phys;
        bus_size_t cnt;
        int dmach, mode;

        _bus_dmamap_sync(t, map, offset, len, ops);

        /*
         * Don't do anything if not using the DMA controller.
         */
        if ((map->_dm_flags & _MCABUS_DMA_USEDMACTRL) == 0)
                return;

        /*
         * Don't do anything if not PRE* operation, allow only
         * one of PREREAD and PREWRITE.
         */
        if (ops != BUS_DMASYNC_PREREAD && ops != BUS_DMASYNC_PREWRITE)
                return;

        cookie = (struct rs6000_dma_cookie *)map->_dm_cookie;
        dmach = (cookie->id_flags & 0xf0) >> 4;

        phys = map->dm_segs[0].ds_addr;
        cnt = map->dm_segs[0].ds_len;

        mode = DMACMD_MODE_XFER;
        mode |= (ops == BUS_DMASYNC_PREREAD)
                        ? DMACMD_MODE_READ : DMACMD_MODE_WRITE;
        if (map->_dm_flags & MCABUS_DMA_IOPORT)
                mode |= DMACMD_MODE_IOPORT;

        /* Use 16bit DMA if requested */
        if (map->_dm_flags & MCABUS_DMA_16BIT) {
#ifdef DIAGNOSTIC
                if ((cnt % 2) != 0) {
                        panic("_mca_bus_dmamap_sync: 16bit DMA and cnt %lu odd",
                                cnt);
                }
#endif 
                mode |= DMACMD_MODE_16BIT;
                cnt /= 2;
        }

        /*
         * Initialize the MCA DMA controller appropriately. The exact
         * sequence to setup the controller is taken from Minix.
         */

        /* Disable access to DMA channel. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_MASK | dmach);

        /* Set the transfer mode. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_MODE | dmach);
        bus_space_write_1(dmaiot, dmaexech, 0, mode);

        /* Set the address byte pointer. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_ADDR | dmach);
        /* address bits 0..7   */
        bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 0) & 0xff);
        /* address bits 8..15  */
        bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 8) & 0xff);
        /* address bits 16..23  */
        bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 16) & 0xff);

        /* Set the count byte pointer */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_CNT | dmach);
        /* count bits 0..7     */
        bus_space_write_1(dmaiot, dmaexech, 0, ((cnt - 1) >> 0) & 0xff);        
        /* count bits 8..15    */
        bus_space_write_1(dmaiot, dmaexech, 0, ((cnt - 1) >> 8) & 0xff);        

        /* Enable access to DMA channel. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_RESET_MASK | dmach);
}
#endif

/*
 * Allocate a DMA map, and set up DMA channel.
 */
int
mca_dmamap_create(bus_dma_tag_t t, bus_size_t size, int flags,
    bus_dmamap_t *dmamp, int dmach)
{
#if 0
        int error;
        struct rs6000_dma_cookie *cookie;

#ifdef DEBUG
        /* Sanity check */
        if (dmach < 0 || dmach >= MAX_DMA_CHANNELS) {
                printf("mcadma_create: invalid DMA channel %d\n",
                        dmach);
                return (EINVAL);
        }

        if (size > 65536) {
                panic("mca_dmamap_create: dmamap sz %ld > 65536",
                    (long) size);
        }
#endif

        /*
         * MCA DMA transfer can be maximum 65536 bytes long and must
         * be in one chunk. No specific boundary constraints are present.
         */
        if ((error = _bus_dmamap_create(t, size, 1, 65536, 0, flags, dmamp)))
                return (error);

        cookie = (struct rs6000_dma_cookie *) (*dmamp)->_dm_cookie;

        if (cookie == NULL) {
                /*
                 * Allocate our cookie if not yet done.
                 */
                cookie = kmem_zalloc(sizeof(struct rs6000_dma_cookie),
                    ((flags & BUS_DMA_NOWAIT) ? KM_SLEEP : KM_NOSLEEP));
                if (cookie == NULL) {
                        
                        return ENOMEM;
                }
                (*dmamp)->_dm_cookie = cookie;
        }


        /* Encode DMA channel */
        cookie->id_flags &= 0x0f;
        cookie->id_flags |= dmach << 4;

        /* Mark the dmamap as using DMA controller. Some devices
         * drive DMA themselves, and don't need the MCA DMA controller.
         * To distinguish the two, use a flag for dmamaps which use the DMA
         * controller.
         */
        (*dmamp)->_dm_flags |= _MCABUS_DMA_USEDMACTRL;
#endif
        return (0);
}

/*
 * Set I/O port for DMA. Implemented separately from _mca_bus_dmamap_sync()
 * so that it's available for one-shot setup.
 */
void
mca_dma_set_ioport(int dma, uint16_t port)
{
#if 0
        /* Disable access to dma channel. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_MASK | dma);

        /* Set I/O port to use for DMA */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_IO | dma);
        bus_space_write_1(dmaiot, dmaexech, 0, port & 0xff);
        bus_space_write_1(dmaiot, dmaexech, 0, (port >> 8) & 0xff);

        /* Enable access to DMA channel. */
        bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_RESET_MASK | dma);
#endif
}