/*      $NetBSD: atari5380.c,v 1.67 2026/04/26 10:52:14 thorpej Exp $   */

/*
 * Copyright (c) 1995 Leo Weppelman.
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: atari5380.c,v 1.67 2026/04/26 10:52:14 thorpej Exp $");

#include "opt_atariscsi.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsi_message.h>
#include <dev/scsipi/scsiconf.h>

#include <uvm/uvm_extern.h>

#include <m68k/asm_single.h>
#include <m68k/cpu.h>
#include <m68k/cacheops.h>

#include <atari/atari/stalloc.h>

/*
 * Include the driver definitions
 */
#include <atari/dev/ncr5380reg.h>

#include <machine/iomap.h>
#include <machine/mfp.h>
#include <machine/intr.h>

#if defined(FALCON_SCSI)
#include <machine/dma.h>
#endif

/*
 * Set the various driver options
 */
#define NREQ            18      /* Size of issue queue                  */
#define AUTO_SENSE      1       /* Automatically issue a request-sense  */

#define DRNAME          ncrscsi /* used in various prints               */
#undef  DBG_SEL                 /* Show the selection process           */
#undef  DBG_REQ                 /* Show enqueued/ready requests         */
#undef  DBG_ERR_RET             /* Show requests with != 0 return code  */
#undef  DBG_NOWRITE             /* Do not allow writes to the targets   */
#undef  DBG_PIO                 /* Show the polled-I/O process          */
#undef  DBG_INF                 /* Show information transfer process    */
#define DBG_NOSTATIC            /* No static functions, all in DDB trace*/
#define DBG_PID         15      /* Keep track of driver                 */
#define REAL_DMA                /* Use DMA if sensible                  */
#if defined(FALCON_SCSI)
#define REAL_DMA_POLL   1       /* 1: Poll for end of DMA-transfer      */
#else
#define REAL_DMA_POLL   0       /* 1: Poll for end of DMA-transfer      */
#endif
#undef  USE_PDMA                /* Use special pdma-transfer function   */
#define MIN_PHYS        65536   /*BARF!!!!*/

/*
 * Include more driver definitions
 */
#include <atari/dev/ncr5380var.h>

/*
 * The atari specific driver options
 */
#undef  NO_TTRAM_DMA            /* Do not use DMA to TT-ram. This       */
                                /*    fails on older atari's            */
#define ENABLE_NCR5380(sc)      cur_softc = sc;

static uint8_t  *alloc_bounceb(u_long);
static void     free_bounceb(uint8_t *);
static int      machine_match(device_t, cfdata_t, void *, struct cfdriver *);

void    scsi_ctrl(int);
void    scsi_dma(int);

/*
 * Functions that do nothing on the atari
 */
#define pdma_ready()            0

#if defined(TT_SCSI)

void    ncr5380_drq_intr(int);

/*
 * Define all the things we need of the DMA-controller
 */
#define SCSI_DMA        ((struct scsi_dma *)AD_SCSI_DMA)
#define SCSI_5380       ((struct scsi_5380 *)AD_NCR5380)

struct scsi_dma {
        volatile uint8_t        s_dma_ptr[8];   /* use only the odd bytes */
        volatile uint8_t        s_dma_cnt[8];   /* use only the odd bytes */
        volatile uint8_t        s_dma_res[4];   /* data residue register  */
        volatile uint8_t        s_dma_gap;      /* not used               */
        volatile uint8_t        s_dma_ctrl;     /* control register       */
        volatile uint8_t        s_dma_gap2;     /* not used               */
        volatile uint8_t        s_hdma_ctrl;    /* Hades control register */
};

static inline void set_scsi_dma(volatile uint8_t *, u_long);
static inline u_long get_scsi_dma(volatile uint8_t *);

static inline void
set_scsi_dma(volatile uint8_t *addr, u_long val)
{
        volatile uint8_t *address;

        address = addr + 1;
        __asm("movepl   %0, %1@(0)": :"d" (val), "a" (address));
}

static inline u_long
get_scsi_dma(volatile uint8_t *addr)
{
        volatile uint8_t *address;
        u_long  nval;

        address = addr + 1;
        __asm("movepl   %1@(0), %0": "=d" (nval) : "a" (address));

        return nval;
}

/*
 * Defines for TT-DMA control register
 */
#define SD_BUSERR       0x80            /* 1 = transfer caused bus error*/
#define SD_ZERO         0x40            /* 1 = byte counter is zero     */
#define SD_ENABLE       0x02            /* 1 = Enable DMA               */
#define SD_OUT          0x01            /* Direction: memory to SCSI    */
#define SD_IN           0x00            /* Direction: SCSI to memory    */

/*
 * Defines for Hades-DMA control register
 */
#define SDH_BUSERR      0x02            /* 1 = Bus error                */
#define SDH_EOP         0x01            /* 1 = Signal EOP on 5380       */
#define SDH_ZERO        0x40            /* 1 = Byte counter is zero     */

/*
 * Define the 5380 register set
 */
struct scsi_5380 {
        volatile uint8_t scsi_5380[16]; /* use only the odd bytes       */
};
#endif /* TT_SCSI */

/**********************************************
 * Variables present for both TT and Falcon.  *
 **********************************************/

/*
 * Softc of currently active controller (a bit of fake; we only have one)
 */
static struct ncr_softc *cur_softc;

#if defined(TT_SCSI) && !defined(FALCON_SCSI)
/*
 * We can be more efficient for some functions when only TT_SCSI is selected
 */
#define GET_5380_REG(rnum)      SCSI_5380->scsi_5380[(rnum << 1) | 1]
#define SET_5380_REG(rnum,val)  (SCSI_5380->scsi_5380[(rnum << 1) | 1] = val)

#define scsi_mach_init(sc)      scsi_tt_init(sc)
#define scsi_ienable()          scsi_tt_ienable()
#define scsi_idisable()         scsi_tt_idisable()
#define scsi_clr_ipend()        scsi_tt_clr_ipend()
#define scsi_ipending()         (GET_5380_REG(NCR5380_DMSTAT) & SC_IRQ_SET)
#define scsi_dma_setup(r,p,m)   scsi_tt_dmasetup(r, p, m)
#define wrong_dma_range(r,d)    tt_wrong_dma_range(r, d)
#define poll_edma(reqp)         tt_poll_edma(reqp)
#define get_dma_result(r, b)    tt_get_dma_result(r, b)
#define can_access_5380()       1
#define emulated_dma()          ((machineid & ATARI_HADES) ? 1 : 0)

#define fair_to_keep_dma()      1
#define claimed_dma()           1
#define reconsider_dma()

#endif /* defined(TT_SCSI) && !defined(FALCON_SCSI) */

#if defined(TT_SCSI)

/*
 * Prototype functions defined below
 */
#ifdef NO_TTRAM_DMA
static int tt_wrong_dma_range(SC_REQ *, struct dma_chain *);
#endif
static void     scsi_tt_init(struct ncr_softc *);
static uint8_t  get_tt_5380_reg(u_short);
static void     set_tt_5380_reg(u_short, u_short);
static void     scsi_tt_dmasetup(SC_REQ *, u_int, uint8_t);
static int      tt_poll_edma(SC_REQ *);
static uint8_t  *ptov(SC_REQ *, u_long*);
static int      tt_get_dma_result(SC_REQ *, u_long *);

void    scsi_tt_ienable(void);
void    scsi_tt_idisable(void);
void    scsi_tt_clr_ipend(void);

/*
 * Define these too, so we can use them locally...
 */
#define GET_TT_REG(rnum)        SCSI_5380->scsi_5380[(rnum << 1) | 1]
#define SET_TT_REG(rnum,val)    (SCSI_5380->scsi_5380[(rnum << 1) | 1] = val)

#ifdef NO_TTRAM_DMA
static int
tt_wrong_dma_range(SC_REQ *reqp, struct dma_chain *dm)
{

        if (dm->dm_addr & 0xff000000) {
                reqp->dr_flag |= DRIVER_BOUNCING;
                return 1;
        }
        return 0;
}
#else
#define tt_wrong_dma_range(reqp, dm)    0
#endif

static void
scsi_tt_init(struct ncr_softc *sc)
{

        /*
         * Enable SCSI-related interrupts
         */
        MFP2->mf_aer  |= 0x80;          /* SCSI IRQ goes HIGH!!!!!      */

        if (machineid & ATARI_TT) {
                /* SCSI-DMA interrupts          */
                MFP2->mf_ierb |= IB_SCDM;
                MFP2->mf_iprb  = (uint8_t)~IB_SCDM;
                MFP2->mf_imrb |= IB_SCDM;
        } else if (machineid & ATARI_HADES) {
                SCSI_DMA->s_hdma_ctrl = 0;

                if (intr_establish(2, AUTO_VEC, 0,
                    (hw_ifun_t)ncr5380_drq_intr, NULL) == NULL)
                panic("scsi_tt_init: Can't establish drq-interrupt");
        } else
                panic("scsi_tt_init: should not come here");

        MFP2->mf_iera |= IA_SCSI;       /* SCSI-5380 interrupts         */
        MFP2->mf_ipra  = (uint8_t)~IA_SCSI;
        MFP2->mf_imra |= IA_SCSI;

        /*
         * LWP: DMA transfers to TT-ram causes data to be garbled
         * without notice on some TT-mainboard revisions.
         * If programs generate mysterious Segmentations faults,
         * try enabling NO_TTRAM_DMA.
         */
#ifdef NO_TTRAM_DMA
        printf(": DMA to TT-RAM is disabled!");
#endif
}

static uint8_t
get_tt_5380_reg(u_short rnum)
{

        return SCSI_5380->scsi_5380[(rnum << 1) | 1];
}

static void
set_tt_5380_reg(u_short rnum, u_short val)
{

        SCSI_5380->scsi_5380[(rnum << 1) | 1] = val;
}

static inline void
scsi_tt_ienable(void)
{

        if (machineid & ATARI_TT)
                single_inst_bset_b(MFP2->mf_imrb, IB_SCDM);
        single_inst_bset_b(MFP2->mf_imra, IA_SCSI);
}

static inline void
scsi_tt_idisable(void)
{

        if (machineid & ATARI_TT)
                single_inst_bclr_b(MFP2->mf_imrb, IB_SCDM);
        single_inst_bclr_b(MFP2->mf_imra, IA_SCSI);
}

static inline void
scsi_tt_clr_ipend(void)
{
        SCSI_DMA->s_dma_ctrl = 0;
        GET_TT_REG(NCR5380_IRCV);
        if (machineid & ATARI_TT)
                MFP2->mf_iprb = (uint8_t)~IB_SCDM;
        MFP2->mf_ipra = (uint8_t)~IA_SCSI;

        /*
         * Remove interrupts already scheduled.
         */
        rem_sicallback((si_farg)ncr_ctrl_intr);
        rem_sicallback((si_farg)ncr_dma_intr);
}

static void
scsi_tt_dmasetup(SC_REQ *reqp, u_int phase, uint8_t mode)
{

        if (PH_IN(phase)) {
                SCSI_DMA->s_dma_ctrl = SD_IN;
                if (machineid & ATARI_HADES)
                        SCSI_DMA->s_hdma_ctrl &= ~(SDH_BUSERR|SDH_EOP);
                set_scsi_dma(SCSI_DMA->s_dma_ptr, reqp->dm_cur->dm_addr);
                set_scsi_dma(SCSI_DMA->s_dma_cnt, reqp->dm_cur->dm_count);
                SET_TT_REG(NCR5380_ICOM, 0);
                SET_TT_REG(NCR5380_MODE, mode);
                SCSI_DMA->s_dma_ctrl = SD_ENABLE;
                SET_TT_REG(NCR5380_IRCV, 0);
        } else {
                SCSI_DMA->s_dma_ctrl = SD_OUT;
                if (machineid & ATARI_HADES)
                        SCSI_DMA->s_hdma_ctrl &= ~(SDH_BUSERR|SDH_EOP);
                set_scsi_dma(SCSI_DMA->s_dma_ptr, reqp->dm_cur->dm_addr);
                set_scsi_dma(SCSI_DMA->s_dma_cnt, reqp->dm_cur->dm_count);
                SET_TT_REG(NCR5380_MODE, mode);
                SET_TT_REG(NCR5380_ICOM, SC_ADTB);
                SET_TT_REG(NCR5380_DMSTAT, 0);
                SCSI_DMA->s_dma_ctrl = SD_ENABLE|SD_OUT;
        }
}

static int
tt_poll_edma(SC_REQ *reqp)
{
        uint8_t dmstat, dmastat;
        int     timeout = 9000; /* XXX */

        /*
         * We wait here until the DMA has finished. This can be
         * achieved by checking the following conditions:
         *   - 5380:
         *      - End of DMA flag is set
         *      - We lost BSY (error!!)
         *      - A phase mismatch has occurred (partial transfer)
         *   - DMA-controller:
         *      - A bus error occurred (Kernel error!!)
         *      - All bytes are transferred
         * If one of the terminating conditions was met, we call
         * 'dma_ready' to check errors and perform the bookkeeping.
         */

        scsi_tt_idisable();
        for (;;) {
                delay(20);
                if (--timeout <= 0) {
                        ncr_tprint(reqp, "timeout on polled transfer\n");
                        reqp->xs->error = XS_TIMEOUT;
                        scsi_tt_ienable();
                        return 0;
                }
                dmstat  = GET_TT_REG(NCR5380_DMSTAT);

                if ((machineid & ATARI_HADES) && (dmstat & SC_DMA_REQ)) {
                        ncr5380_drq_intr(1);
                        dmstat  = GET_TT_REG(NCR5380_DMSTAT);
                }

                dmastat = SCSI_DMA->s_dma_ctrl;
                if (dmstat & (SC_END_DMA|SC_BSY_ERR|SC_IRQ_SET))
                        break;
                if ((dmstat & SC_PHS_MTCH) == 0)
                        break;
                if (dmastat & (SD_BUSERR|SD_ZERO))
                        break;
        }
        scsi_tt_ienable();
        return 1;
}

/*
 * Convert physical DMA address to a virtual address.
 */
static uint8_t *
ptov(SC_REQ *reqp, u_long *phaddr)
{
        struct dma_chain        *dm;
        uint8_t                 *vaddr;

        dm = reqp->dm_chain;
        vaddr = reqp->xdata_ptr;
        for (; dm < reqp->dm_cur; dm++)
                vaddr += dm->dm_count;
        vaddr += (u_long)phaddr - dm->dm_addr;
        return vaddr;
}

static int
tt_get_dma_result(SC_REQ *reqp, u_long *bytes_left)
{
        int     dmastat, dmstat;
        uint8_t *byte_p;
        u_long  leftover;

        dmastat = SCSI_DMA->s_dma_ctrl;
        dmstat  = GET_TT_REG(NCR5380_DMSTAT);
        leftover = get_scsi_dma(SCSI_DMA->s_dma_cnt);
        byte_p = (uint8_t *)get_scsi_dma(SCSI_DMA->s_dma_ptr);

        if (dmastat & SD_BUSERR) {
                /*
                 * The DMA-controller seems to access 8 bytes beyond
                 * its limits on output. Therefore check also the byte
                 * count. If it's zero, ignore the bus error.
                 */
                if (leftover != 0) {
                        ncr_tprint(reqp,
                            "SCSI-DMA buserror - accessing 0x%x\n", byte_p);
                        reqp->xs->error = XS_DRIVER_STUFFUP;
                }
        }

        /*
         * We handle the following special condition below:
         *  -- The device disconnects in the middle of a write operation --
         * In this case, the 5380 has already pre-fetched the next byte from
         * the DMA-controller before the phase mismatch occurs. Therefore,
         * leftover is 1 too low.
         * This does not always happen! Therefore, we only do this when
         * leftover is odd. This assumes that DMA transfers are _even_! This
         * is normally the case on disks and types but might not always be.
         * XXX: Check if ACK is consistently high on these occasions LWP
         */
        if ((leftover & 1) &&
            (dmstat & SC_PHS_MTCH) == 0 && PH_OUT(reqp->phase))
                leftover++;

        /*
         * Check if there are some 'restbytes' left in the DMA-controller.
         */
        if ((machineid & ATARI_TT) &&
            ((u_long)byte_p & 3) && PH_IN(reqp->phase)) {
                uint8_t *p;
                volatile uint8_t *q;

                p = ptov(reqp, (u_long *)((u_long)byte_p & ~3));
                q = SCSI_DMA->s_dma_res;
                switch ((u_long)byte_p & 3) {
                        case 3: *p++ = *q++;
                        case 2: *p++ = *q++;
                        case 1: *p++ = *q++;
                }
        }
        *bytes_left = leftover;
        return (dmastat & (SD_BUSERR|SD_ZERO)) ? 1 : 0;
}

static uint8_t *dma_ptr;
void
ncr5380_drq_intr(int poll)
{
        label_t faultbuf;
        int write;
        u_long count;
        volatile uint8_t *data_p = (volatile uint8_t *)(stio_addr + 0x741);

        /*
         * Block SCSI interrupts while emulating DMA. They come
         * at a higher priority.
         */
        single_inst_bclr_b(MFP2->mf_imra, IA_SCSI);

        /*
         * Setup for a possible bus error caused by SCSI controller
         * switching out of DATA-IN/OUT before we're done with the
         * current transfer.
         */
        nofault = &faultbuf;

        if (setjmp(nofault)) {
                u_long cnt, tmp;

                PID("drq berr");
                nofault = NULL;

                /*
                 * Determine number of bytes transferred
                 */
                cnt = (u_long)dma_ptr - get_scsi_dma(SCSI_DMA->s_dma_ptr);

                if (cnt != 0) {
                        /*
                         * Update the DMA pointer/count fields
                         */
                        set_scsi_dma(SCSI_DMA->s_dma_ptr, (u_long)dma_ptr);
                        tmp = get_scsi_dma(SCSI_DMA->s_dma_cnt);
                        set_scsi_dma(SCSI_DMA->s_dma_cnt, tmp - cnt);

                        if (tmp > cnt) {
                                /*
                                 * Still more to transfer
                                 */
                                if (!poll)
                                        single_inst_bset_b(MFP2->mf_imra,
                                            IA_SCSI);
                                return;
                        }

                        /*
                         * Signal EOP to 5380
                         */
                        SCSI_DMA->s_hdma_ctrl |= SDH_EOP;
                } else {
                        nofault = &faultbuf;

                        /*
                         * Try to figure out if the byte-count was
                         * zero because there was no (more) data or
                         * because the dma_ptr is bogus.
                         */
                        if (setjmp(nofault)) {
                                /*
                                 * Set the bus-error bit
                                 */
                                SCSI_DMA->s_hdma_ctrl |= SDH_BUSERR;
                        }
                        __asm volatile ("tstb   %0@(0)": : "a" (dma_ptr));
                        nofault = NULL;
                }

                /*
                 * Schedule an interrupt
                 */
                if (!poll && (SCSI_DMA->s_dma_ctrl & SD_ENABLE))
                        add_sicallback((si_farg)ncr_dma_intr,
                            (void *)cur_softc, 0);

                /*
                 * Clear DMA-mode
                 */
                SCSI_DMA->s_dma_ctrl &= ~SD_ENABLE;
                if (!poll)
                        single_inst_bset_b(MFP2->mf_imra, IA_SCSI);

                return;
        }

        write = (SCSI_DMA->s_dma_ctrl & SD_OUT) ? 1 : 0;
#if DBG_PID
        if (write) {
                PID("drq (in)");
        } else {
                PID("drq (out)");
        }
#endif

        count = get_scsi_dma(SCSI_DMA->s_dma_cnt);
        dma_ptr = (uint8_t *)get_scsi_dma(SCSI_DMA->s_dma_ptr);

        /*
         * Keep pushing bytes until we're done or a bus-error
         * signals that the SCSI controller is not ready.
         * NOTE: I tried some optimalizations in these loops,
         *       but they had no effect on transfer speed.
         */
        if (write) {
                while (count--) {
                        *data_p = *dma_ptr++;
                }
        } else {
                while (count--) {
                        *dma_ptr++ = *data_p;
                }
        }

        /*
         * OK.  No bus error occurred above.  Clear the nofault flag
         * so we no longer short-circuit bus errors.
         */
        nofault = NULL;

        /*
         * Schedule an interrupt
         */
        if (!poll && (SCSI_DMA->s_dma_ctrl & SD_ENABLE))
                add_sicallback((si_farg)ncr_dma_intr, (void *)cur_softc, 0);

        /*
         * Clear DMA-mode
         */
        SCSI_DMA->s_dma_ctrl &= ~SD_ENABLE;

        /*
         * Update the DMA 'registers' to reflect that all bytes
         * have been transferred and tell this to the 5380 too.
         */
        set_scsi_dma(SCSI_DMA->s_dma_ptr, (u_long)dma_ptr);
        set_scsi_dma(SCSI_DMA->s_dma_cnt, 0);
        SCSI_DMA->s_hdma_ctrl |= SDH_EOP;

        PID("end drq");
        if (!poll)
                single_inst_bset_b(MFP2->mf_imra, IA_SCSI);
}

#endif /* defined(TT_SCSI) */

#if defined(FALCON_SCSI) && !defined(TT_SCSI)

#define GET_5380_REG(rnum)      get_falcon_5380_reg(rnum)
#define SET_5380_REG(rnum,val)  set_falcon_5380_reg(rnum, val)
#define scsi_mach_init(sc)      scsi_falcon_init(sc)
#define scsi_ienable()          scsi_falcon_ienable()
#define scsi_idisable()         scsi_falcon_idisable()
#define scsi_clr_ipend()        scsi_falcon_clr_ipend()
#define scsi_ipending()         scsi_falcon_ipending()
#define scsi_dma_setup(r,p,m)   scsi_falcon_dmasetup(r, p, m)
#define wrong_dma_range(r,d)    falcon_wrong_dma_range(r, d)
#define poll_edma(reqp)         falcon_poll_edma(reqp)
#define get_dma_result(r, b)    falcon_get_dma_result(r, b)
#define can_access_5380()       falcon_can_access_5380()
#define emulated_dma()          0

#define fair_to_keep_dma()      (!st_dmawanted())
#define claimed_dma()           falcon_claimed_dma()
#define reconsider_dma()        falcon_reconsider_dma()

#endif /* defined(FALCON_SCSI) && !defined(TT_SCSI) */

#if defined(FALCON_SCSI)

/*
 * Prototype functions defined below
 */
static void     scsi_falcon_init(struct ncr_softc *);
static uint8_t  get_falcon_5380_reg(u_short);
static void     set_falcon_5380_reg(u_short, u_short);
static int      falcon_wrong_dma_range(SC_REQ *, struct dma_chain *);
static void     fal1_dma(u_int, u_int, SC_REQ *);
static void     scsi_falcon_dmasetup(SC_REQ  *, u_int, uint8_t);
static int      falcon_poll_edma(SC_REQ  *);
static int      falcon_get_dma_result(SC_REQ  *, u_long *);

int     falcon_can_access_5380(void);
void    scsi_falcon_clr_ipend(void);
void    scsi_falcon_idisable(void);
void    scsi_falcon_ienable(void);
int     scsi_falcon_ipending(void);
int     falcon_claimed_dma(void);
void    falcon_reconsider_dma(void);

static void
scsi_falcon_init(struct ncr_softc *sc)
{

        /*
         * Enable disk related interrupts
         */
        MFP->mf_ierb  |= IB_DINT;
        MFP->mf_iprb   = (uint8_t)~IB_DINT;
        MFP->mf_imrb  |= IB_DINT;
}

static uint8_t
get_falcon_5380_reg(u_short rnum)
{

        DMA->dma_mode = DMA_SCSI + rnum;
        return DMA->dma_data;
}

static void
set_falcon_5380_reg(u_short rnum, u_short val)
{

        DMA->dma_mode = DMA_SCSI + rnum;
        DMA->dma_data = val;
}

static inline void
scsi_falcon_ienable(void)
{

        single_inst_bset_b(MFP->mf_imrb, IB_DINT);
}

static inline void
scsi_falcon_idisable(void)
{

        single_inst_bclr_b(MFP->mf_imrb, IB_DINT);
}

static inline void
scsi_falcon_clr_ipend(void)
{

        (void)get_falcon_5380_reg(NCR5380_IRCV);
        rem_sicallback((si_farg)ncr_ctrl_intr);
}

static inline int
scsi_falcon_ipending(void)
{

        if (connected && (connected->dr_flag & DRIVER_IN_DMA)) {
                /*
                 *  XXX: When DMA is running, we are only allowed to
                 *       check the 5380 when DMA _might_ be finished.
                 */
                if (MFP->mf_gpip & IO_DINT)
                        /* XXX: Actually: we're not allowed to check */
                        return 0;

                /* LWP: 28-06, must be a DMA interrupt! should the
                 * ST-DMA unit be taken out of DMA mode?????
                 */
                DMA->dma_mode = 0x90;

        }
        return get_falcon_5380_reg(NCR5380_DMSTAT) & SC_IRQ_SET;
}

static int
falcon_wrong_dma_range(SC_REQ *reqp, struct dma_chain *dm)
{

        /*
         * Do not allow chains yet! See also comment with
         * falcon_poll_edma() !!!
         */
        if (((dm - reqp->dm_chain) > 0) || (dm->dm_addr & 0xff000000)) {
                reqp->dr_flag |= DRIVER_BOUNCING;
                return 1;
        }
        /*
         * Never allow DMA to happen on a Falcon when the transfer
         * size is no multiple of 512. This is the transfer unit of the
         * ST DMA-controller.
         */
        if (dm->dm_count & 511)
                return 1;
        return 0;
}

static  int falcon_lock = 0;

static inline int
falcon_claimed_dma(void)
{

        if (falcon_lock != DMA_LOCK_GRANT) {
                if (falcon_lock == DMA_LOCK_REQ) {
                        /*
                         * DMA access is being claimed.
                         */
                        return 0;
                }
                if (st_dmagrab((dma_farg)ncr_ctrl_intr, (dma_farg)run_main,
                    cur_softc, &falcon_lock, 1, NULL) == 0)
                        return 0;
        }
        return 1;
}

static inline void
falcon_reconsider_dma(void)
{

        if (falcon_lock && (connected == NULL) && (discon_q == NULL)) {
                /*
                 * No need to keep DMA locked by us as we are not currently
                 * connected and no disconnected jobs are pending.
                 */
                rem_sicallback((si_farg)ncr_ctrl_intr);
                st_dmafree(cur_softc, &falcon_lock);
        }

        if (!falcon_lock && (issue_q != NULL)) {
                /*
                 * We must (re)claim DMA access as there are jobs
                 * waiting in the issue queue.
                 */
                st_dmagrab((dma_farg)ncr_ctrl_intr, (dma_farg)run_main,
                    cur_softc, &falcon_lock, 0, NULL);
        }
}

static void
fal1_dma(u_int dir, u_int nsects, SC_REQ *reqp)
{

        dir <<= 8;
        st_dmaaddr_set((void *)reqp->dm_cur->dm_addr);
        DMA->dma_mode = 0x90 | dir;
        DMA->dma_mode = 0x90 | (dir ^ DMA_WRBIT);
        DMA->dma_mode = 0x90 | dir;
        DMA->dma_data = nsects;
        delay(2);       /* _really_ needed (Thomas Gerner) */
        DMA->dma_mode = 0x10 | dir;
}

static void
scsi_falcon_dmasetup(SC_REQ *reqp, u_int phase, uint8_t mode)
{
        int nsects = reqp->dm_cur->dm_count / 512; /* XXX */

        /*
         * XXX: We should probably clear the fifo before putting the
         *      5380 into DMA-mode.
         */
        if (PH_IN(phase)) {
                set_falcon_5380_reg(NCR5380_ICOM, 0);
                set_falcon_5380_reg(NCR5380_MODE, mode);
                set_falcon_5380_reg(NCR5380_IRCV, 0);
                fal1_dma(0, nsects, reqp);
        } else {
                set_falcon_5380_reg(NCR5380_MODE, mode);
                set_falcon_5380_reg(NCR5380_ICOM, SC_ADTB);
                set_falcon_5380_reg(NCR5380_DMSTAT, 0);
                fal1_dma(1, nsects, reqp);
        }
}

static int
falcon_poll_edma(SC_REQ *reqp)
{
        int timeout = 9000; /* XXX */

        /*
         * Because of the Falcon hardware, it is impossible to reach
         * the 5380 while doing DMA-transfers. So we have to rely on
         * the interrupt line to determine if DMA-has finished. the
         * DMA-controller itself will never fire an interrupt. This means
         * that 'broken-up' DMA transfers are not (yet) possible on the
         * Falcon.
         */
        for (;;) {
                delay(20);
                if (--timeout <= 0) {
                        ncr_tprint(reqp, "Timeout on polled transfer\n");
                        reqp->xs->error = XS_TIMEOUT;
                        return 0;
                }
                if ((MFP->mf_gpip & IO_DINT) == 0)
                        break;
        }
        return 1;
}

static int
falcon_get_dma_result(SC_REQ *reqp, u_long *bytes_left)
{
        int     rv = 0;
        int     st_dmastat;
        u_long  bytes_done;

        /*
         * Select sector counter register first (See Atari docu.)
         */
        DMA->dma_mode = 0x90;
        if (!(st_dmastat = DMA->dma_stat) & 0x01) {
                /*
                 * Misc. DMA-error according to Atari...
                 */
                ncr_tprint(reqp, "Unknown ST-SCSI error near 0x%x\n",
                    st_dmaaddr_get());
                reqp->xs->error = XS_DRIVER_STUFFUP;
                rv = 1;
        }
        /*
         * Because we NEVER start DMA on the Falcon when the data size
         * is not a multiple of 512 bytes, we can safely round down the
         * byte count on writes. We need to because in case of a disconnect,
         * the DMA has already prefetched the next couple of bytes.
         * On read, these byte counts are an error. They are logged and
         * should be handled by the mi-part of the driver.
         * NOTE: We formerly did this by using the 'byte-count-zero' bit
         *       of the DMA controller, but this didn't seem to work???
         *       [lwp 29/06/96]
         */
        bytes_done = st_dmaaddr_get() - reqp->dm_cur->dm_addr;
        if (bytes_done & 511) {
                if (PH_IN(reqp->phase)) {
                        ncr_tprint(reqp, "Byte count on read not a multiple "
                            "of 512 (%ld)\n", bytes_done);
                }
                bytes_done &= ~511;
        }
        if ((*bytes_left = reqp->dm_cur->dm_count - bytes_done) == 0)
                rv = 1;
        return rv;
}

static int
falcon_can_access_5380(void)
{

        if (connected && (connected->dr_flag & DRIVER_IN_DMA) &&
            (MFP->mf_gpip & IO_DINT))
                return 0;
        return 1;
}

#endif /* defined(FALCON_SCSI) */

#if defined(TT_SCSI) && defined(FALCON_SCSI)
/*
 * Define some functions to support _both_ TT and Falcon SCSI
 */

/*
 * The prototypes first...
 */
static void     scsi_mach_init(struct ncr_softc *);

void    scsi_ienable(void);
void    scsi_idisable(void);
void    scsi_clr_ipend(void);
int     scsi_ipending(void);
void    scsi_dma_setup(SC_REQ *, u_int, uint8_t);
int     wrong_dma_range(SC_REQ *, struct dma_chain *);
int     poll_edma(SC_REQ *);
int     get_dma_result(SC_REQ *, u_long *);
int     can_access_5380(void);

/*
 * Register access will be done through the following 2 function pointers.
 */
static uint8_t  (*get_5380_reg)(u_short);
static void     (*set_5380_reg)(u_short, u_short);

#define GET_5380_REG    (*get_5380_reg)
#define SET_5380_REG    (*set_5380_reg)

static void
scsi_mach_init(struct ncr_softc *sc)
{

        if (machineid & ATARI_FALCON) {
                get_5380_reg = get_falcon_5380_reg;
                set_5380_reg = set_falcon_5380_reg;
                scsi_falcon_init(sc);
        } else {
                get_5380_reg = get_tt_5380_reg;
                set_5380_reg = set_tt_5380_reg;
                scsi_tt_init(sc);
        }
}

static inline void
scsi_ienable(void)
{

        if (machineid & ATARI_FALCON)
                scsi_falcon_ienable();
        else
                scsi_tt_ienable();
}

static inline void
scsi_idisable(void)
{

        if (machineid & ATARI_FALCON)
                scsi_falcon_idisable();
        else
                scsi_tt_idisable();
}

static inline void
scsi_clr_ipend(void)
{

        if (machineid & ATARI_FALCON)
                scsi_falcon_clr_ipend();
        else
                scsi_tt_clr_ipend();
}

static inline int
scsi_ipending(void)
{

        if (machineid & ATARI_FALCON)
                return scsi_falcon_ipending();
        else
                return GET_TT_REG(NCR5380_DMSTAT) & SC_IRQ_SET;
}

static inline void
scsi_dma_setup(SC_REQ *reqp, u_int phase, uint8_t mbase)
{

        if (machineid & ATARI_FALCON)
                scsi_falcon_dmasetup(reqp, phase, mbase);
        else
                scsi_tt_dmasetup(reqp, phase, mbase);
}

static inline int
wrong_dma_range(SC_REQ *reqp, struct dma_chain *dm)
{

        if (machineid & ATARI_FALCON)
                return falcon_wrong_dma_range(reqp, dm);
        else
                return tt_wrong_dma_range(reqp, dm);
}

static inline int
poll_edma(SC_REQ *reqp)
{

        if (machineid & ATARI_FALCON)
                return falcon_poll_edma(reqp);
        else
                return tt_poll_edma(reqp);
}

static inline int
get_dma_result(SC_REQ *reqp, u_long *bytes_left)
{

        if (machineid & ATARI_FALCON)
                return falcon_get_dma_result(reqp, bytes_left);
        else
                return tt_get_dma_result(reqp, bytes_left);
}

static inline int
can_access_5380(void)
{

        if (machineid & ATARI_FALCON)
                return falcon_can_access_5380();
        return 1;
}

#define emulated_dma()          ((machineid & ATARI_HADES) ? 1 : 0)

/*
 * Locking stuff. All turns into NOP's on the TT.
 */
#define fair_to_keep_dma()                                              \
        ((machineid & ATARI_FALCON) ? !st_dmawanted() : 1)
#define claimed_dma()                                                   \
        ((machineid & ATARI_FALCON) ? falcon_claimed_dma() : 1)
#define reconsider_dma()                                                \
        do {                                                            \
                if (machineid & ATARI_FALCON)                           \
                        falcon_reconsider_dma();                        \
        } while (/* CONSTCOND */ 0)
#endif /* defined(TT_SCSI) && defined(FALCON_SCSI) */

/**********************************************
 * Functions present for both TT and Falcon.  *
 **********************************************/
/*
 * Our autoconfig matching function
 */
static int
machine_match(device_t parent, cfdata_t cf, void *aux, struct cfdriver *cd)
{
        static int we_matched = 0; /* Only one unit     */

        if (strcmp(aux, cd->cd_name) || we_matched)
                return 0;

        we_matched = 1;
        return 1;
}

/*
 * Bounce buffer (de)allocation. Those buffers are gotten from the ST-mem
 * pool. Allocation here is both contiguous and in the lower 16Mb of
 * the address space. Thus being DMA-able for all controllers.
 */
static uint8_t *
alloc_bounceb(u_long len)
{
        void *tmp;

        return (uint8_t *)alloc_stmem(len, &tmp);
}

static void
free_bounceb(uint8_t *bounceb)
{

        free_stmem(bounceb);
}

/*
 * 5380 interrupt.
 */
void
scsi_ctrl(int sr)
{

        if (GET_5380_REG(NCR5380_DMSTAT) & SC_IRQ_SET) {
                scsi_idisable();
                add_sicallback((si_farg)ncr_ctrl_intr, (void *)cur_softc, 0);
        }
}

/*
 * DMA controller interrupt
 */
void
scsi_dma(int sr)
{
        SC_REQ  *reqp;

        if ((reqp = connected) && (reqp->dr_flag & DRIVER_IN_DMA)) {
                scsi_idisable();
                add_sicallback((si_farg)ncr_dma_intr, (void *)cur_softc, 0);
        }
}

/*
 * Last but not least... Include the general driver code
 */
#include <atari/dev/ncr5380.c>