/*      $NetBSD: dma.c,v 1.48 2024/04/30 09:55:45 tsutsui Exp $ */

/*-
* Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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.
*/

/*
* Copyright (c) 1982, 1990, 1993
*      The Regents of the University of California.  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.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
*      @(#)dma.c       8.1 (Berkeley) 6/10/93
*/

/*
* DMA driver
*/

#include "opt_m68k_arch.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dma.c,v 1.48 2024/04/30 09:55:45 tsutsui Exp $");

#include <machine/hp300spu.h>   /* XXX param.h includes cpu.h */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/proc.h>

#include <uvm/uvm_extern.h>

#include <machine/bus.h>

#include <m68k/cacheops.h>

#include <hp300/dev/intiovar.h>
#include <hp300/dev/dmareg.h>
#include <hp300/dev/dmavar.h>

/*
* The largest single request will be MAXPHYS bytes which will require
* at most MAXPHYS/PAGE_SIZE+1 chain elements to describe, i.e. if none of
* the buffer pages are physically contiguous (MAXPHYS/PAGE_SIZE) and the
* buffer is not page aligned (+1).
*/
#define DMAMAXIO        (MAXPHYS/PAGE_SIZE+1)

struct dma_chain {
       int     dc_count;
       char    *dc_addr;
};

struct dma_channel {
       struct  dmaqueue *dm_job;               /* current job */
       struct  dmadevice *dm_hwaddr;           /* registers if DMA_C */
       struct  dmaBdevice *dm_Bhwaddr;         /* registers if not DMA_C */
       char    dm_flags;                       /* misc. flags */
       u_short dm_cmd;                         /* DMA controller command */
       int     dm_cur;                         /* current segment */
       int     dm_last;                        /* last segment */
       struct  dma_chain dm_chain[DMAMAXIO];   /* all segments */
};

struct dma_softc {
       device_t sc_dev;
       bus_space_tag_t sc_bst;
       bus_space_handle_t sc_bsh;

       struct  dmareg *sc_dmareg;              /* pointer to our hardware */
       struct  dma_channel sc_chan[NDMACHAN];  /* 2 channels */
       TAILQ_HEAD(, dmaqueue) sc_queue;        /* job queue */
       struct  callout sc_debug_ch;
       char    sc_type;                        /* A, B, or C */
       int     sc_ipl;                         /* our interrupt level */
       void    *sc_ih;                         /* interrupt cookie */
};

/* types */
#define DMA_B   0
#define DMA_C   1

/* flags */
#define DMAF_PCFLUSH    0x01
#define DMAF_VCFLUSH    0x02
#define DMAF_NOINTR     0x04

static int      dmamatch(device_t, cfdata_t, void *);
static void     dmaattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(dma, sizeof(struct dma_softc),
   dmamatch, dmaattach, NULL, NULL);

static int      dmaintr(void *);

#ifdef DEBUG
int     dmadebug = 0;
#define DDB_WORD        0x01    /* same as DMAGO_WORD */
#define DDB_LWORD       0x02    /* same as DMAGO_LWORD */
#define DDB_FOLLOW      0x04
#define DDB_IO          0x08

static void     dmatimeout(void *);
int     dmatimo[NDMACHAN];

long    dmahits[NDMACHAN];
long    dmamisses[NDMACHAN];
long    dmabyte[NDMACHAN];
long    dmaword[NDMACHAN];
long    dmalword[NDMACHAN];
#endif

static struct dma_softc *dma_softc;

static int
dmamatch(device_t parent, cfdata_t cf, void *aux)
{
       struct intio_attach_args *ia = aux;
       static int dmafound = 0;                /* can only have one */

       if (strcmp("dma", ia->ia_modname) != 0 || dmafound)
               return 0;

       dmafound = 1;
       return 1;
}

static void
dmaattach(device_t parent, device_t self, void *aux)
{
       struct dma_softc *sc = device_private(self);
       struct intio_attach_args *ia = aux;
       struct dma_channel *dc;
       struct dmareg *dma;
       int i;
       char rev;

       sc->sc_dev = self;

       /* There's just one. */
       dma_softc = sc;

       sc->sc_bst = ia->ia_bst;
       if (bus_space_map(sc->sc_bst, ia->ia_iobase, INTIO_DEVSIZE, 0,
            &sc->sc_bsh)) {
               aprint_error(": can't map registers\n");
               return;
       }

       dma = bus_space_vaddr(sc->sc_bst, sc->sc_bsh);
       sc->sc_dmareg = dma;

       /*
        * Determine the DMA type.  A DMA_A or DMA_B will fail the
        * following probe.
        *
        * XXX Don't know how to easily differentiate the A and B cards,
        * so we just hope nobody has an A card (A cards will work if
        * splbio works out to ipl 3).
        */
       if (hp300_bus_space_probe(sc->sc_bst, sc->sc_bsh, DMA_ID2, 1) == 0) {
               rev = 'B';
#if !defined(HP320)
               aprint_normal("\n");
               panic("%s: DMA card requires hp320 support", __func__);
#endif
       } else
               rev = dma->dma_id[2];

       sc->sc_type = (rev == 'B') ? DMA_B : DMA_C;

       TAILQ_INIT(&sc->sc_queue);
       callout_init(&sc->sc_debug_ch, 0);

       for (i = 0; i < NDMACHAN; i++) {
               dc = &sc->sc_chan[i];
               dc->dm_job = NULL;
               switch (i) {
               case 0:
                       dc->dm_hwaddr = &dma->dma_chan0;
                       dc->dm_Bhwaddr = &dma->dma_Bchan0;
                       break;

               case 1:
                       dc->dm_hwaddr = &dma->dma_chan1;
                       dc->dm_Bhwaddr = &dma->dma_Bchan1;
                       break;

               default:
                       aprint_normal("\n");
                       panic("%s: more than 2 channels?", __func__);
                       /* NOTREACHED */
               }
       }

#ifdef DEBUG
       /* make sure timeout is really not needed */
       callout_reset(&sc->sc_debug_ch, 30 * hz, dmatimeout, sc);
#endif

       aprint_normal(": 98620%c, 2 channels, %d-bit DMA\n",
           rev, (rev == 'B') ? 16 : 32);

       /*
        * Defer hooking up our interrupt until the first
        * DMA-using controller has hooked up theirs.
        */
       sc->sc_ih = NULL;
}

/*
* Compute the ipl and (re)establish the interrupt handler
* for the DMA controller.
*/
void
dmaupdateipl(int ipl)
{
       struct dma_softc *sc = dma_softc;

       if (sc->sc_ih != NULL && sc->sc_ipl == ipl) {
               /* No change. */
               return;
       }

       if (sc->sc_ih != NULL) {
               intr_disestablish(sc->sc_ih);
       }

       if ((sc->sc_ipl = ipl) == 0) {
               /* Don't hook up a new handler. */
               return;
       }

       sc->sc_ih = intr_establish(dmaintr, sc, sc->sc_ipl, ISRPRI_BIO);
       if (sc->sc_type == DMA_B && sc->sc_ipl != 3) {
               aprint_error_dev(sc->sc_dev,
                   "WARNING: IPL set to %d on maybe-rev. A card!\n",
                   sc->sc_ipl);
       }
}

int
dmareq(struct dmaqueue *dq)
{
       struct dma_softc *sc = dma_softc;
       int i, chan, s;

#if 1
       s = splhigh();  /* XXXthorpej */
#else
       s = splbio();
#endif

       chan = dq->dq_chan;
       for (i = NDMACHAN - 1; i >= 0; i--) {
               /*
                * Can we use this channel?
                */
               if ((chan & (1 << i)) == 0)
                       continue;

               /*
                * We can use it; is it busy?
                */
               if (sc->sc_chan[i].dm_job != NULL)
                       continue;

               /*
                * Not busy; give the caller this channel.
                */
               sc->sc_chan[i].dm_job = dq;
               dq->dq_chan = i;
               splx(s);
               return 1;
       }

       /*
        * Couldn't get a channel now; put this in the queue.
        */
       TAILQ_INSERT_TAIL(&sc->sc_queue, dq, dq_list);
       splx(s);
       return 0;
}

void
dmafree(struct dmaqueue *dq)
{
       int unit = dq->dq_chan;
       struct dma_softc *sc = dma_softc;
       struct dma_channel *dc = &sc->sc_chan[unit];
       struct dmaqueue *dn;
       int chan, s;

#if 1
       s = splhigh();  /* XXXthorpej */
#else
       s = splbio();
#endif

#ifdef DEBUG
       dmatimo[unit] = 0;
#endif

       DMA_CLEAR(dc);

#if defined(CACHE_HAVE_PAC) || defined(M68040)
       /*
        * XXX we may not always go thru the flush code in dmastop()
        */
       if (dc->dm_flags & DMAF_PCFLUSH) {
               PCIA();
               dc->dm_flags &= ~DMAF_PCFLUSH;
       }
#endif

#if defined(CACHE_HAVE_VAC)
       if (dc->dm_flags & DMAF_VCFLUSH) {
               /*
                * 320/350s have VACs that may also need flushing.
                * In our case we only flush the supervisor side
                * because we know that if we are DMAing to user
                * space, the physical pages will also be mapped
                * in kernel space (via vmapbuf) and hence cache-
                * inhibited by the pmap module due to the multiple
                * mapping.
                */
               DCIS();
               dc->dm_flags &= ~DMAF_VCFLUSH;
       }
#endif

       /*
        * Channel is now free.  Look for another job to run on this
        * channel.
        */
       dc->dm_job = NULL;
       chan = 1 << unit;
       for (dn = TAILQ_FIRST(&sc->sc_queue); dn != NULL;
           dn = TAILQ_NEXT(dn, dq_list)) {
               if (dn->dq_chan & chan) {
                       /* Found one... */
                       TAILQ_REMOVE(&sc->sc_queue, dn, dq_list);
                       dc->dm_job = dn;
                       dn->dq_chan = dq->dq_chan;
                       splx(s);

                       /* Start the initiator. */
                       (*dn->dq_start)(dn->dq_softc);
                       return;
               }
       }
       splx(s);
}

void
dmago(int unit, char *addr, int count, int flags)
{
       struct dma_softc *sc = dma_softc;
       struct dma_channel *dc = &sc->sc_chan[unit];
       char *dmaend = NULL;
       int seg, tcount;

       if (count > MAXPHYS)
               panic("dmago: count > MAXPHYS");

#if defined(HP320)
       if (sc->sc_type == DMA_B && (flags & DMAGO_LWORD))
               panic("dmago: no can do 32-bit DMA");
#endif

#ifdef DEBUG
       if (dmadebug & DDB_FOLLOW)
               printf("dmago(%d, %p, %x, %x)\n",
                      unit, addr, count, flags);
       if (flags & DMAGO_LWORD)
               dmalword[unit]++;
       else if (flags & DMAGO_WORD)
               dmaword[unit]++;
       else
               dmabyte[unit]++;
#endif
       /*
        * Build the DMA chain
        */
       for (seg = 0; count > 0; seg++) {
               dc->dm_chain[seg].dc_addr = (char *) kvtop(addr);
#if defined(M68040)
               /*
                * Push back dirty cache lines
                */
               if (mmutype == MMU_68040)
                       DCFP((paddr_t)dc->dm_chain[seg].dc_addr);
#endif
               if (count < (tcount = PAGE_SIZE - ((int)addr & PGOFSET)))
                       tcount = count;
               dc->dm_chain[seg].dc_count = tcount;
               addr += tcount;
               count -= tcount;
               if (flags & DMAGO_LWORD)
                       tcount >>= 2;
               else if (flags & DMAGO_WORD)
                       tcount >>= 1;

               /*
                * Try to compact the DMA transfer if the pages are adjacent.
                * Note: this will never happen on the first iteration.
                */
               if (dc->dm_chain[seg].dc_addr == dmaend
#if defined(HP320)
                   /* only 16-bit count on 98620B */
                   && (sc->sc_type != DMA_B ||
                       dc->dm_chain[seg - 1].dc_count + tcount <= 65536)
#endif
               ) {
#ifdef DEBUG
                       dmahits[unit]++;
#endif
                       dmaend += dc->dm_chain[seg].dc_count;
                       dc->dm_chain[--seg].dc_count += tcount;
               } else {
#ifdef DEBUG
                       dmamisses[unit]++;
#endif
                       dmaend = dc->dm_chain[seg].dc_addr +
                           dc->dm_chain[seg].dc_count;
                       dc->dm_chain[seg].dc_count = tcount;
               }
       }
       dc->dm_cur = 0;
       dc->dm_last = --seg;
       dc->dm_flags = 0;
       /*
        * Set up the command word based on flags
        */
       dc->dm_cmd = DMA_ENAB | DMA_IPL(sc->sc_ipl) | DMA_START;
       if ((flags & DMAGO_READ) == 0)
               dc->dm_cmd |= DMA_WRT;
       if (flags & DMAGO_LWORD)
               dc->dm_cmd |= DMA_LWORD;
       else if (flags & DMAGO_WORD)
               dc->dm_cmd |= DMA_WORD;
       if (flags & DMAGO_PRI)
               dc->dm_cmd |= DMA_PRI;

#if defined(M68040)
       /*
        * On the 68040 we need to flush (push) the data cache before a
        * DMA (already done above) and flush again after DMA completes.
        * In theory we should only need to flush prior to a write DMA
        * and purge after a read DMA but if the entire page is not
        * involved in the DMA we might purge some valid data.
        */
       if (mmutype == MMU_68040 && (flags & DMAGO_READ))
               dc->dm_flags |= DMAF_PCFLUSH;
#endif

#if defined(CACHE_HAVE_PAC)
       /*
        * Remember if we need to flush external physical cache when
        * DMA is done.  We only do this if we are reading (writing memory).
        */
       if (ectype == EC_PHYS && (flags & DMAGO_READ))
               dc->dm_flags |= DMAF_PCFLUSH;
#endif

#if defined(CACHE_HAVE_VAC)
       if (ectype == EC_VIRT && (flags & DMAGO_READ))
               dc->dm_flags |= DMAF_VCFLUSH;
#endif

       /*
        * Remember if we can skip the dma completion interrupt on
        * the last segment in the chain.
        */
       if (flags & DMAGO_NOINT) {
               if (dc->dm_cur == dc->dm_last)
                       dc->dm_cmd &= ~DMA_ENAB;
               else
                       dc->dm_flags |= DMAF_NOINTR;
       }
#ifdef DEBUG
       if (dmadebug & DDB_IO) {
               if (((dmadebug&DDB_WORD) && (dc->dm_cmd&DMA_WORD)) ||
                   ((dmadebug&DDB_LWORD) && (dc->dm_cmd&DMA_LWORD))) {
                       printf("dmago: cmd %x, flags %x\n",
                           dc->dm_cmd, dc->dm_flags);
                       for (seg = 0; seg <= dc->dm_last; seg++)
                               printf("  %d: %d@%p\n", seg,
                                   dc->dm_chain[seg].dc_count,
                                   dc->dm_chain[seg].dc_addr);
               }
       }
       dmatimo[unit] = 1;
#endif
       DMA_ARM(sc, dc);
}

void
dmastop(int unit)
{
       struct dma_softc *sc = dma_softc;
       struct dma_channel *dc = &sc->sc_chan[unit];

#ifdef DEBUG
       if (dmadebug & DDB_FOLLOW)
               printf("dmastop(%d)\n", unit);
       dmatimo[unit] = 0;
#endif
       DMA_CLEAR(dc);

#if defined(CACHE_HAVE_PAC) || defined(M68040)
       if (dc->dm_flags & DMAF_PCFLUSH) {
               PCIA();
               dc->dm_flags &= ~DMAF_PCFLUSH;
       }
#endif

#if defined(CACHE_HAVE_VAC)
       if (dc->dm_flags & DMAF_VCFLUSH) {
               /*
                * 320/350s have VACs that may also need flushing.
                * In our case we only flush the supervisor side
                * because we know that if we are DMAing to user
                * space, the physical pages will also be mapped
                * in kernel space (via vmapbuf) and hence cache-
                * inhibited by the pmap module due to the multiple
                * mapping.
                */
               DCIS();
               dc->dm_flags &= ~DMAF_VCFLUSH;
       }
#endif

       /*
        * We may get this interrupt after a device service routine
        * has freed the dma channel.  So, ignore the intr if there's
        * nothing on the queue.
        */
       if (dc->dm_job != NULL)
               (*dc->dm_job->dq_done)(dc->dm_job->dq_softc);
}

static int
dmaintr(void *arg)
{
       struct dma_softc *sc = arg;
       struct dma_channel *dc;
       int i, stat;
       int found = 0;

#ifdef DEBUG
       if (dmadebug & DDB_FOLLOW)
               printf("dmaintr\n");
#endif
       for (i = 0; i < NDMACHAN; i++) {
               dc = &sc->sc_chan[i];
               stat = DMA_STAT(dc);
               if ((stat & DMA_INTR) == 0)
                       continue;
               found++;
#ifdef DEBUG
               if (dmadebug & DDB_IO) {
                       if (((dmadebug&DDB_WORD) && (dc->dm_cmd&DMA_WORD)) ||
                           ((dmadebug&DDB_LWORD) && (dc->dm_cmd&DMA_LWORD)))
                               printf("dmaintr: flags %x unit %d stat %x "
                                   "next %d\n",
                                   dc->dm_flags, i, stat, dc->dm_cur + 1);
               }
               if (stat & DMA_ARMED)
                       printf("dma channel %d: intr when armed\n", i);
#endif
               /*
                * Load the next segment, or finish up if we're done.
                */
               dc->dm_cur++;
               if (dc->dm_cur <= dc->dm_last) {
#ifdef DEBUG
                       dmatimo[i] = 1;
#endif
                       /*
                        * If we're the last segment, disable the
                        * completion interrupt, if necessary.
                        */
                       if (dc->dm_cur == dc->dm_last &&
                           (dc->dm_flags & DMAF_NOINTR))
                               dc->dm_cmd &= ~DMA_ENAB;
                       DMA_CLEAR(dc);
                       DMA_ARM(sc, dc);
               } else
                       dmastop(i);
       }
       return found;
}

#ifdef DEBUG
static void
dmatimeout(void *arg)
{
       int i, s;
       struct dma_softc *sc = arg;

       for (i = 0; i < NDMACHAN; i++) {
               s = splbio();
               if (dmatimo[i]) {
                       if (dmatimo[i] > 1)
                               printf("dma channel %d timeout #%d\n",
                                   i, dmatimo[i]-1);
                       dmatimo[i]++;
               }
               splx(s);
       }
       callout_reset(&sc->sc_debug_ch, 30 * hz, dmatimeout, sc);
}
#endif