/*      $NetBSD: si_sebuf.c,v 1.34 2025/12/16 18:24:47 andvar Exp $     */

/*-
 * Copyright (c) 1996 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Gordon W. Ross.
 *
 * 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.
 */

/*
 * Sun3/E SCSI driver (machine-dependent portion).
 * The machine-independent parts are in ncr5380sbc.c
 *
 * XXX - Mostly from the si driver.  Merge?
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: si_sebuf.c,v 1.34 2025/12/16 18:24:47 andvar Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/proc.h>

#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsipi_debug.h>
#include <dev/scsipi/scsiconf.h>

#include <machine/autoconf.h>

/* #define DEBUG XXX */

#include <dev/ic/ncr5380reg.h>
#include <dev/ic/ncr5380var.h>

#include "sereg.h"
#include "sevar.h"

/*
 * Transfers smaller than this are done using PIO
 * (on assumption they're not worth DMA overhead)
 */
#define MIN_DMA_LEN 128

/*
 * Transfers larger than 65535 bytes need to be split-up.
 * (Some of the FIFO logic has only 16 bits counters.)
 * Make the size an integer multiple of the page size
 * to avoid buf/cluster remap problems.  (paranoid?)
 */
#define MAX_DMA_LEN 0xE000

/*
 * This structure is used to keep track of mapped DMA requests.
 */
struct se_dma_handle {
        int             dh_flags;
#define SIDH_BUSY       1               /* This DH is in use */
#define SIDH_OUT        2               /* DMA does data out (write) */
        u_char *        dh_addr;        /* KVA of start of buffer */
        int             dh_maplen;      /* Length of KVA mapping. */
        long            dh_dma;         /* Offset in DMA buffer. */
};

/*
 * The first structure member has to be the ncr5380_softc
 * so we can just cast to go back and fourth between them.
 */
struct se_softc {
        struct ncr5380_softc    ncr_sc;
        volatile struct se_regs *sc_regs;
        int             sc_adapter_type;
        int             sc_adapter_iv;          /* int. vec */
        int     sc_options;                     /* options for this instance */
        int     sc_reqlen;              /* requested transfer length */
        struct se_dma_handle *sc_dma;
        /* DMA command block for the OBIO controller. */
        void *sc_dmacmd;
};

/* Options for disconnect/reselect, DMA, and interrupts. */
#define SE_NO_DISCONNECT    0xff
#define SE_NO_PARITY_CHK  0xff00
#define SE_FORCE_POLLING 0x10000
#define SE_DISABLE_DMA   0x20000

void se_dma_alloc(struct ncr5380_softc *);
void se_dma_free(struct ncr5380_softc *);
void se_dma_poll(struct ncr5380_softc *);

void se_dma_setup(struct ncr5380_softc *);
void se_dma_start(struct ncr5380_softc *);
void se_dma_eop(struct ncr5380_softc *);
void se_dma_stop(struct ncr5380_softc *);

void se_intr_on (struct ncr5380_softc *);
void se_intr_off(struct ncr5380_softc *);

static int  se_intr(void *);
static void se_reset(struct ncr5380_softc *);

/*
 * New-style autoconfig attachment
 */

static int      se_match(device_t, cfdata_t, void *);
static void     se_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(si_sebuf, sizeof(struct se_softc),
    se_match, se_attach, NULL, NULL);

static void     se_minphys(struct buf *);

/* Options for disconnect/reselect, DMA, and interrupts. */
int se_options = SE_DISABLE_DMA | SE_FORCE_POLLING | 0xff;

/* How long to wait for DMA before declaring an error. */
int se_dma_intr_timo = 500;     /* ticks (sec. X 100) */

int se_debug = 0;

static int
se_match(device_t parent, cfdata_t cf, void *args)
{
        struct sebuf_attach_args *aa = args;

        /* Match by name. */
        if (strcmp(aa->name, "se"))
                return 0;

        /* Anything else to check? */

        return 1;
}

static void
se_attach(device_t parent, device_t self, void *args)
{
        struct se_softc *sc = device_private(self);
        struct ncr5380_softc *ncr_sc = &sc->ncr_sc;
        struct cfdata *cf = device_cfdata(self);
        struct sebuf_attach_args *aa = args;
        volatile struct se_regs *regs;
        int i;

        ncr_sc->sc_dev = self;

        /* Get options from config flags if specified. */
        if (cf->cf_flags)
                sc->sc_options = cf->cf_flags;
        else
                sc->sc_options = se_options;

        aprint_normal(": options=0x%x\n", sc->sc_options);

        sc->sc_adapter_type = aa->ca.ca_bustype;
        sc->sc_adapter_iv = aa->ca.ca_intvec;
        sc->sc_regs = regs = aa->regs;

        /*
         * MD function pointers used by the MI code.
         */
        ncr_sc->sc_pio_out = ncr5380_pio_out;
        ncr_sc->sc_pio_in =  ncr5380_pio_in;

#if 0   /* XXX - not yet... */
        ncr_sc->sc_dma_alloc = se_dma_alloc;
        ncr_sc->sc_dma_free  = se_dma_free;
        ncr_sc->sc_dma_setup = se_dma_setup;
        ncr_sc->sc_dma_start = se_dma_start;
        ncr_sc->sc_dma_poll  = se_dma_poll;
        ncr_sc->sc_dma_eop   = se_dma_eop;
        ncr_sc->sc_dma_stop  = se_dma_stop;
        ncr_sc->sc_intr_on   = se_intr_on;
        ncr_sc->sc_intr_off  = se_intr_off;
#endif  /* XXX */

        /* Attach interrupt handler. */
        isr_add_vectored(se_intr, (void *)sc,
            aa->ca.ca_intpri, aa->ca.ca_intvec);

        /* Reset the hardware. */
        se_reset(ncr_sc);

        /* Do the common attach stuff. */

        /*
         * Support the "options" (config file flags).
         * Disconnect/reselect is a per-target mask.
         * Interrupts and DMA are per-controller.
         */
        ncr_sc->sc_no_disconnect =
            (sc->sc_options & SE_NO_DISCONNECT);
        ncr_sc->sc_parity_disable =
            (sc->sc_options & SE_NO_PARITY_CHK) >> 8;
        if (sc->sc_options & SE_FORCE_POLLING)
                ncr_sc->sc_flags |= NCR5380_FORCE_POLLING;

#if 1   /* XXX - Temporary */
        /* XXX - In case we think DMA is completely broken... */
        if (sc->sc_options & SE_DISABLE_DMA) {
                /* Override this function pointer. */
                ncr_sc->sc_dma_alloc = NULL;
        }
#endif
        ncr_sc->sc_min_dma_len = MIN_DMA_LEN;

        /*
         * Initialize fields used by the MI code
         */
        ncr_sc->sci_r0 = &regs->ncrregs[0];
        ncr_sc->sci_r1 = &regs->ncrregs[1];
        ncr_sc->sci_r2 = &regs->ncrregs[2];
        ncr_sc->sci_r3 = &regs->ncrregs[3];
        ncr_sc->sci_r4 = &regs->ncrregs[4];
        ncr_sc->sci_r5 = &regs->ncrregs[5];
        ncr_sc->sci_r6 = &regs->ncrregs[6];
        ncr_sc->sci_r7 = &regs->ncrregs[7];

        ncr_sc->sc_rev = NCR_VARIANT_NCR5380;

        /*
         * Allocate DMA handles.
         */
        i = SCI_OPENINGS * sizeof(struct se_dma_handle);
        sc->sc_dma = kmem_alloc(i, KM_SLEEP);
        for (i = 0; i < SCI_OPENINGS; i++)
                sc->sc_dma[i].dh_flags = 0;

        ncr_sc->sc_channel.chan_id = 7;
        ncr_sc->sc_adapter.adapt_minphys = se_minphys;

        /*
         *  Initialize se board itself.
         */
        ncr5380_attach(ncr_sc);
}

static void
se_reset(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        volatile struct se_regs *se = sc->sc_regs;

#ifdef  DEBUG
        if (se_debug) {
                printf("%s\n", __func__);
        }
#endif

        /* The reset bits in the CSR are active low. */
        se->se_csr = 0;
        delay(10);
        se->se_csr = SE_CSR_SCSI_RES /* | SE_CSR_INTR_EN */ ;
        delay(10);

        /* Make sure the DMA engine is stopped. */
        se->dma_addr = 0;
        se->dma_cntr = 0;
        se->se_ivec = sc->sc_adapter_iv;
}

/*
 * This is called when the bus is going idle,
 * so we want to enable the SBC interrupts.
 * That is controlled by the DMA enable!
 * Who would have guessed!
 * What a NASTY trick!
 */
void
se_intr_on(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        volatile struct se_regs *se = sc->sc_regs;

        /* receive mode should be safer */
        se->se_csr &= ~SE_CSR_SEND;

        /* Clear the count so nothing happens. */
        se->dma_cntr = 0;
        
        /* Clear the start address too. (paranoid?) */
        se->dma_addr = 0;

        /* Finally, enable the DMA engine. */
        se->se_csr |= SE_CSR_INTR_EN;
}

/*
 * This is called when the bus is idle and we are
 * about to start playing with the SBC chip.
 */
void
se_intr_off(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        volatile struct se_regs *se = sc->sc_regs;

        se->se_csr &= ~SE_CSR_INTR_EN;
}

/*
 * This function is called during the COMMAND or MSG_IN phase
 * that precedes a DATA_IN or DATA_OUT phase, in case we need
 * to setup the DMA engine before the bus enters a DATA phase.
 *
 * On the VME version, setup the start address, but clear the
 * count (to make sure it stays idle) and set that later.
 * XXX: The VME adapter appears to suppress SBC interrupts
 * when the FIFO is not empty or the FIFO count is non-zero!
 * XXX: Need to copy data into the DMA buffer...
 */
void
se_dma_setup(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        struct sci_req *sr = ncr_sc->sc_current;
        struct se_dma_handle *dh = sr->sr_dma_hand;
        volatile struct se_regs *se = sc->sc_regs;
        long data_pa;
        int xlen;

        /*
         * Get the DMA mapping for this segment.
         * XXX - Should separate allocation and mapin.
         */
        data_pa = 0; /* XXX se_dma_kvtopa(dh->dh_dma); */
        data_pa += (ncr_sc->sc_dataptr - dh->dh_addr);
        if (data_pa & 1)
                panic("%s: bad pa=0x%lx", __func__, data_pa);
        xlen = ncr_sc->sc_datalen;
        xlen &= ~1;                             /* XXX: necessary? */
        sc->sc_reqlen = xlen;   /* XXX: or less? */

#ifdef  DEBUG
        if (se_debug & 2) {
                printf("%s: dh=%p, pa=0x%lx, xlen=0x%x\n",
                    __func__, dh, data_pa, xlen);
        }
#endif

        /* Set direction (send/recv) */
        if (dh->dh_flags & SIDH_OUT) {
                se->se_csr |= SE_CSR_SEND;
        } else {
                se->se_csr &= ~SE_CSR_SEND;
        }

        /* Load the start address. */
        se->dma_addr = (ushort)(data_pa & 0xFFFF);

        /*
         * Keep the count zero or it may start early!
         */
        se->dma_cntr = 0;
}


void
se_dma_start(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        struct sci_req *sr = ncr_sc->sc_current;
        struct se_dma_handle *dh = sr->sr_dma_hand;
        volatile struct se_regs *se = sc->sc_regs;
        int s, xlen;

        xlen = sc->sc_reqlen;

        /* This MAY be time critical (not sure). */
        s = splhigh();

        se->dma_cntr = (ushort)(xlen & 0xFFFF);

        /*
         * Acknowledge the phase change.  (After DMA setup!)
         * Put the SBIC into DMA mode, and start the transfer.
         */
        if (dh->dh_flags & SIDH_OUT) {
                *ncr_sc->sci_tcmd = PHASE_DATA_OUT;
                SCI_CLR_INTR(ncr_sc);
                *ncr_sc->sci_icmd = SCI_ICMD_DATA;
                *ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
                *ncr_sc->sci_dma_send = 0;      /* start it */
        } else {
                *ncr_sc->sci_tcmd = PHASE_DATA_IN;
                SCI_CLR_INTR(ncr_sc);
                *ncr_sc->sci_icmd = 0;
                *ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
                *ncr_sc->sci_irecv = 0; /* start it */
        }

        /* Let'er rip! */
        se->se_csr |= SE_CSR_INTR_EN;

        splx(s);
        ncr_sc->sc_state |= NCR_DOINGDMA;

#ifdef  DEBUG
        if (se_debug & 2) {
                printf("%s: started, flags=0x%x\n",
                    __func__, ncr_sc->sc_state);
        }
#endif
}


void
se_dma_eop(struct ncr5380_softc *ncr_sc)
{

        /* Not needed - DMA was stopped prior to examining sci_csr */
}


void
se_dma_stop(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        struct sci_req *sr = ncr_sc->sc_current;
        struct se_dma_handle *dh = sr->sr_dma_hand;
        volatile struct se_regs *se = sc->sc_regs;
        int resid, ntrans;

        if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
#ifdef  DEBUG
                printf("%s: DMA not running\n", __func__);
#endif
                return;
        }
        ncr_sc->sc_state &= ~NCR_DOINGDMA;

        /* First, halt the DMA engine. */
        se->se_csr &= ~SE_CSR_INTR_EN;  /* VME only */

        /* Set an impossible phase to prevent data movement? */
        *ncr_sc->sci_tcmd = PHASE_INVALID;

        /* Note that timeout may have set the error flag. */
        if (ncr_sc->sc_state & NCR_ABORTING)
                goto out;

        /* XXX: Wait for DMA to actually finish? */

        /*
         * Now try to figure out how much actually transferred
         */
        resid = se->dma_cntr & 0xFFFF;
        if (dh->dh_flags & SIDH_OUT)
                if ((resid > 0) && (resid < sc->sc_reqlen))
                        resid++;
        ntrans = sc->sc_reqlen - resid;

#ifdef  DEBUG
        if (se_debug & 2) {
                printf("%s: resid=0x%x ntrans=0x%x\n",
                    __func__, resid, ntrans);
        }
#endif

        if (ntrans < MIN_DMA_LEN) {
                printf("se: fifo count: 0x%x\n", resid);
                ncr_sc->sc_state |= NCR_ABORTING;
                goto out;
        }
        if (ntrans > ncr_sc->sc_datalen)
                panic("%s: excess transfer", __func__);

        /* Adjust data pointer */
        ncr_sc->sc_dataptr += ntrans;
        ncr_sc->sc_datalen -= ntrans;

out:
        se->dma_addr = 0;
        se->dma_cntr = 0;

        /* Put SBIC back in PIO mode. */
        *ncr_sc->sci_mode &= ~(SCI_MODE_DMA | SCI_MODE_DMA_IE);
        *ncr_sc->sci_icmd = 0;
}

/*****************************************************************/

static void
se_minphys(struct buf *bp)
{

        if (bp->b_bcount > MAX_DMA_LEN)
                bp->b_bcount = MAX_DMA_LEN;

        minphys(bp);
}


int
se_intr(void *arg)
{
        struct se_softc *sc = arg;
        volatile struct se_regs *se = sc->sc_regs;
        int claimed;
        u_short csr;

        claimed = 0;

        /* SBC interrupt? DMA interrupt? */
        csr = se->se_csr;
        NCR_TRACE("se_intr: csr=0x%x\n", csr);

        if (csr & SE_CSR_SBC_IP) {
                claimed = ncr5380_intr(&sc->ncr_sc);
#ifdef  DEBUG
                if (!claimed) {
                        printf("%s: spurious from SBC\n", __func__);
                }
#endif
                /* Yes, we DID cause this interrupt. */
                claimed = 1;
        }

        return claimed;
}


/*****************************************************************
 * Common functions for DMA
 ****************************************************************/

/*
 * Allocate a DMA handle and put it in sc->sc_dma.  Prepare
 * for DMA transfer.  On the Sun3/E, this means we have to
 * allocate space in the DMA buffer for this transfer.
 */
void
se_dma_alloc(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        struct sci_req *sr = ncr_sc->sc_current;
        struct scsipi_xfer *xs = sr->sr_xs;
        struct se_dma_handle *dh;
        int i, xlen;
        u_long addr;

#ifdef  DIAGNOSTIC
        if (sr->sr_dma_hand != NULL)
                panic("%s: already have DMA handle", __func__);
#endif

        addr = (u_long)ncr_sc->sc_dataptr;
        xlen = ncr_sc->sc_datalen;

        /* If the DMA start addr is misaligned then do PIO */
        if ((addr & 1) || (xlen & 1)) {
                printf("%s: misaligned.\n", __func__);
                return;
        }

        /* Make sure our caller checked sc_min_dma_len. */
        if (xlen < MIN_DMA_LEN)
                panic("%s: xlen=0x%x", __func__, xlen);

        /*
         * Never attempt single transfers of more than 63k, because
         * our count register may be only 16 bits (an OBIO adapter).
         * This should never happen since already bounded by minphys().
         * XXX - Should just segment these...
         */
        if (xlen > MAX_DMA_LEN) {
                printf("%s: excessive xlen=0x%x\n", __func__, xlen);
                ncr_sc->sc_datalen = xlen = MAX_DMA_LEN;
        }

        /* Find free DMA handle.  Guaranteed to find one since we have
           as many DMA handles as the driver has processes. */
        for (i = 0; i < SCI_OPENINGS; i++) {
                if ((sc->sc_dma[i].dh_flags & SIDH_BUSY) == 0)
                        goto found;
        }
        panic("se: no free DMA handles.");
found:

        dh = &sc->sc_dma[i];
        dh->dh_flags = SIDH_BUSY;

        /* Copy the "write" flag for convenience. */
        if (xs->xs_control & XS_CTL_DATA_OUT)
                dh->dh_flags |= SIDH_OUT;

        dh->dh_addr = (uint8_t *)addr;
        dh->dh_maplen  = xlen;
        dh->dh_dma = 0; /* XXX - Allocate space in DMA buffer. */
        /* XXX: dh->dh_dma = alloc(xlen) */
        if (!dh->dh_dma) {
                /* Can't remap segment */
                printf("%s: can't remap %p/0x%x\n",
                    __func__, dh->dh_addr, dh->dh_maplen);
                dh->dh_flags = 0;
                return;
        }

        /* success */
        sr->sr_dma_hand = dh;
}


void
se_dma_free(struct ncr5380_softc *ncr_sc)
{
        struct sci_req *sr = ncr_sc->sc_current;
        struct se_dma_handle *dh = sr->sr_dma_hand;

#ifdef  DIAGNOSTIC
        if (dh == NULL)
                panic("%s: no DMA handle", __func__);
#endif

        if (ncr_sc->sc_state & NCR_DOINGDMA)
                panic("%s: free while in progress", __func__);

        if (dh->dh_flags & SIDH_BUSY) {
                /* XXX: Should separate allocation and mapping. */
                /* XXX: Give back the DMA space. */
                /* XXX: free((void *)dh->dh_dma, dh->dh_maplen); */
                dh->dh_dma = 0;
                dh->dh_flags = 0;
        }
        sr->sr_dma_hand = NULL;
}


#define CSR_MASK SE_CSR_SBC_IP
#define POLL_TIMO       50000   /* X100 = 5 sec. */

/*
 * Poll (spin-wait) for DMA completion.
 * Called right after xx_dma_start(), and
 * xx_dma_stop() will be called next.
 * Same for either VME or OBIO.
 */
void
se_dma_poll(struct ncr5380_softc *ncr_sc)
{
        struct se_softc *sc = (struct se_softc *)ncr_sc;
        struct sci_req *sr = ncr_sc->sc_current;
        volatile struct se_regs *se = sc->sc_regs;
        int tmo;

        /* Make sure DMA started successfully. */
        if (ncr_sc->sc_state & NCR_ABORTING)
                return;

        /*
         * XXX: The Sun driver waits for ~SE_CSR_DMA_ACTIVE here
         * XXX: (on obio) or even worse (on vme) a 10mS. delay!
         * XXX: I really doubt that is necessary...
         */

        /* Wait for any "DMA complete" or error bits. */
        tmo = POLL_TIMO;
        for (;;) {
                if (se->se_csr & CSR_MASK)
                        break;
                if (--tmo <= 0) {
                        printf("se: DMA timeout (while polling)\n");
                        /* Indicate timeout as MI code would. */
                        sr->sr_flags |= SR_OVERDUE;
                        break;
                }
                delay(100);
        }
        NCR_TRACE("se_dma_poll: waited %d\n",
                          POLL_TIMO - tmo);

#ifdef  DEBUG
        if (se_debug & 2) {
                printf("%s: done, csr=0x%x\n", __func__, se->se_csr);
        }
#endif
}