FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/sunscpal.c

     /*      $NetBSD: sunscpal.c,v 1.29 2021/08/07 16:19:12 thorpej Exp $    */
     
     /*
      * Copyright (c) 2001 Matthew Fredette
      * Copyright (c) 1995 David Jones, Gordon W. Ross
      * Copyright (c) 1994 Jarle Greipsland
      * 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. The name of the authors may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     * 4. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by
     *      David Jones and Gordon Ross
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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.
     */
    
    /*
     * This is a machine-independent driver for the Sun "sc"
     * SCSI Bus Controller (SBC).
     *
     * This code should work with any memory-mapped card,
     * and can be shared by multiple adapters that address
     * the card with different register offset spacings.
     * (This can happen on the atari, for example.)
     *
     * Credits, history:
     *
     * Matthew Fredette completely copied revision 1.38 of
     * ncr5380sbc.c, and then heavily modified it to match
     * the Sun sc PAL.  The remaining credits are for
     * ncr5380sbc.c:
     *
     * David Jones is the author of most of the code that now
     * appears in this file, and was the architect of the
     * current overall structure (MI/MD code separation, etc.)
     *
     * Gordon Ross integrated the message phase code, added lots of
     * comments about what happens when and why (re. SCSI spec.),
     * debugged some reentrance problems, and added several new
     * "hooks" needed for the Sun3 "si" adapters.
     *
     * The message in/out code was taken nearly verbatim from
     * the aic6360 driver by Jarle Greipsland.
     *
     * Several other NCR5380 drivers were used for reference
     * while developing this driver, including work by:
     *   The Alice Group (mac68k port) namely:
     *       Allen K. Briggs, Chris P. Caputo, Michael L. Finch,
     *       Bradley A. Grantham, and Lawrence A. Kesteloot
     *   Michael L. Hitch (amiga drivers: sci.c)
     *   Leo Weppelman (atari driver: ncr5380.c)
     * There are others too.  Thanks, everyone.
     *
     * Transliteration to bus_space() performed 9/17/98 by
     * John Ruschmeyer (jruschme@exit109.com) for i386 'nca' driver.
     * Thank you all.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: sunscpal.c,v 1.29 2021/08/07 16:19:12 thorpej Exp $");
    
    #include "opt_ddb.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/errno.h>
    #include <sys/malloc.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/scsi_message.h>
    #include <dev/scsipi/scsiconf.h>
    
    #ifdef DDB
    #include <ddb/db_output.h>
   #endif
   
   #include <dev/ic/sunscpalreg.h>
   #include <dev/ic/sunscpalvar.h>
   
   static void     sunscpal_reset_scsibus(struct sunscpal_softc *);
   static void     sunscpal_sched(struct sunscpal_softc *);
   static void     sunscpal_done(struct sunscpal_softc *);
   
   static int      sunscpal_select(struct sunscpal_softc *, struct sunscpal_req *);
   static void     sunscpal_reselect(struct sunscpal_softc *);
   
   static int      sunscpal_msg_in(struct sunscpal_softc *);
   static int      sunscpal_msg_out(struct sunscpal_softc *);
   static int      sunscpal_data_xfer(struct sunscpal_softc *, int);
   static int      sunscpal_command(struct sunscpal_softc *);
   static int      sunscpal_status(struct sunscpal_softc *);
   static void     sunscpal_machine(struct sunscpal_softc *);
   
   void    sunscpal_abort(struct sunscpal_softc *);
   void    sunscpal_cmd_timeout(void *);
   /*
    * Action flags returned by the info_transfer functions:
    * (These determine what happens next.)
    */
   #define ACT_CONTINUE    0x00    /* No flags: expect another phase */
   #define ACT_DISCONNECT  0x01    /* Target is disconnecting */
   #define ACT_CMD_DONE    0x02    /* Need to call scsipi_done() */
   #define ACT_RESET_BUS   0x04    /* Need bus reset (cmd timeout) */
   #define ACT_WAIT_DMA    0x10    /* Wait for DMA to complete */
   
   /*****************************************************************
    * Debugging stuff
    *****************************************************************/
   
   #ifndef DDB
   /* This is used only in recoverable places. */
   #ifndef Debugger
   #define Debugger() printf("Debug: sunscpal.c:%d\n", __LINE__)
   #endif
   #endif
   
   #ifdef  SUNSCPAL_DEBUG
   
   #define SUNSCPAL_DBG_BREAK      1
   #define SUNSCPAL_DBG_CMDS       2
   #define SUNSCPAL_DBG_DMA        4
   int sunscpal_debug = 0;
   #define SUNSCPAL_BREAK() \
           do { if (sunscpal_debug & SUNSCPAL_DBG_BREAK) Debugger(); } while (0)
   static void sunscpal_show_scsi_cmd(struct scsipi_xfer *);
   #ifdef DDB
   void    sunscpal_clear_trace(void);
   void    sunscpal_show_trace(void);
   void    sunscpal_show_req(struct sunscpal_req *);
   void    sunscpal_show_state(void);
   #endif  /* DDB */
   #else   /* SUNSCPAL_DEBUG */
   
   #define SUNSCPAL_BREAK()                /* nada */
   #define sunscpal_show_scsi_cmd(xs) /* nada */
   
   #endif  /* SUNSCPAL_DEBUG */
   
   static const char *
   phase_names[8] = {
           "DATA_OUT",
           "DATA_IN",
           "COMMAND",
           "STATUS",
           "UNSPEC1",
           "UNSPEC2",
           "MSG_OUT",
           "MSG_IN",
   };
   
   #ifdef SUNSCPAL_USE_BUS_DMA
   static void sunscpal_dma_alloc(struct sunscpal_softc *);
   static void sunscpal_dma_free(struct sunscpal_softc *);
   static void sunscpal_dma_setup(struct sunscpal_softc *);
   #else
   #define sunscpal_dma_alloc(sc) (*sc->sc_dma_alloc)(sc)
   #define sunscpal_dma_free(sc) (*sc->sc_dma_free)(sc)
   #define sunscpal_dma_setup(sc) (*sc->sc_dma_setup)(sc)
   #endif
   static void sunscpal_minphys(struct buf *);
   
   /*****************************************************************
    * Actual chip control
    *****************************************************************/
   
   /*
    * XXX: These timeouts might need to be tuned...
    */
   
   /* This one is used when waiting for a phase change. (X100uS.) */
   int sunscpal_wait_phase_timo = 1000 * 10 * 300; /* 5 min. */
   
   /* These are used in the following inline functions. */
   int sunscpal_wait_req_timo = 1000 * 50; /* X2 = 100 mS. */
   int sunscpal_wait_nrq_timo = 1000 * 25; /* X2 =  50 mS. */
   
   static inline int sunscpal_wait_req(struct sunscpal_softc *);
   static inline int sunscpal_wait_not_req(struct sunscpal_softc *);
   static inline void sunscpal_sched_msgout(struct sunscpal_softc *, int);
   
   /* Return zero on success. */
   static inline int sunscpal_wait_req(struct sunscpal_softc *sc)
   {
           int timo = sunscpal_wait_req_timo;
   
           for (;;) {
                   if (SUNSCPAL_READ_2(sc, sunscpal_icr) & SUNSCPAL_ICR_REQUEST) {
                           timo = 0;       /* return 0 */
                           break;
                   }
                   if (--timo < 0)
                           break;  /* return -1 */
                   delay(2);
           }
           return timo;
   }
   
   /* Return zero on success. */
   static inline int sunscpal_wait_not_req(struct sunscpal_softc *sc)
   {
           int timo = sunscpal_wait_nrq_timo;
   
           for (;;) {
                   if ((SUNSCPAL_READ_2(sc, sunscpal_icr) &
                       SUNSCPAL_ICR_REQUEST) == 0) {
                           timo = 0;       /* return 0 */
                           break;
                   }
                   if (--timo < 0)
                           break;  /* return -1 */
                   delay(2);
           }
           return timo;
   }
   
   /*
    * These functions control DMA functions in the chipset independent of
    * the host DMA implementation.
    */
   static void sunscpal_dma_start(struct sunscpal_softc *);
   static void sunscpal_dma_poll(struct sunscpal_softc *);
   static void sunscpal_dma_stop(struct sunscpal_softc *);
   
   static void
   sunscpal_dma_start(struct sunscpal_softc *sc)
   {
           struct sunscpal_req *sr = sc->sc_current;
           int xlen;
           uint16_t icr;
   
           xlen = sc->sc_reqlen;
   
           /* Let'er rip! */
           icr = SUNSCPAL_READ_2(sc, sunscpal_icr);
           icr |= SUNSCPAL_ICR_DMA_ENABLE |
               ((xlen & 1) ? 0 : SUNSCPAL_ICR_WORD_MODE) |
               ((sr->sr_flags & SR_IMMED) ? 0 : SUNSCPAL_ICR_INTERRUPT_ENABLE);
           SUNSCPAL_WRITE_2(sc, sunscpal_icr, icr);
   
           sc->sc_state |= SUNSCPAL_DOINGDMA;
   
   #ifdef  SUNSCPAL_DEBUG
           if (sunscpal_debug & SUNSCPAL_DBG_DMA) {
                   printf("%s: started, flags=0x%x\n",
                       __func__, sc->sc_state);
           }
   #endif
   }
   
   #define ICR_MASK (SUNSCPAL_ICR_PARITY_ERROR | SUNSCPAL_ICR_BUS_ERROR | SUNSCPAL_ICR_INTERRUPT_REQUEST)
   #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.
    */
   static void
   sunscpal_dma_poll(struct sunscpal_softc *sc)
   {
           struct sunscpal_req *sr = sc->sc_current;
           int tmo;
   
           /* Make sure DMA started successfully. */
           if (sc->sc_state & SUNSCPAL_ABORTING)
                   return;
   
           /* Wait for any "DMA complete" or error bits. */
           tmo = POLL_TIMO;
           for (;;) {
                   if (SUNSCPAL_READ_2(sc, sunscpal_icr) & ICR_MASK)
                           break;
                   if (--tmo <= 0) {
                           printf("sc: DMA timeout (while polling)\n");
                           /* Indicate timeout as MI code would. */
                           sr->sr_flags |= SR_OVERDUE;
                           break;
                   }
                   delay(100);
           }
           SUNSCPAL_TRACE("sunscpal_dma_poll: waited %d\n", POLL_TIMO - tmo);
   
   #ifdef  SUNSCPAL_DEBUG
           if (sunscpal_debug & SUNSCPAL_DBG_DMA) {
                   char buffer[64];
                   snprintb(buffer, sizeof(buffer),
                       SUNSCPAL_READ_2(sc, sunscpal_icr), SUNSCPAL_ICR_BITS);
                   printf("%s: done, icr=%s\n", __func__, buffer);
           }
   #endif
   }
   
   static void
   sunscpal_dma_stop(struct sunscpal_softc *sc)
   {
           struct sunscpal_req *sr = sc->sc_current;
           struct scsipi_xfer *xs = sr->sr_xs;
           int resid, ntrans;
           uint16_t icr;
   
           if ((sc->sc_state & SUNSCPAL_DOINGDMA) == 0) {
   #ifdef  DEBUG
                   printf("%s: DMA not running\n", __func__);
   #endif
                   return;
           }
           sc->sc_state &= ~SUNSCPAL_DOINGDMA;
   
           /* First, halt the DMA engine. */
           icr = SUNSCPAL_READ_2(sc, sunscpal_icr);
           icr &= ~(SUNSCPAL_ICR_DMA_ENABLE | SUNSCPAL_ICR_WORD_MODE |
               SUNSCPAL_ICR_INTERRUPT_ENABLE);
           SUNSCPAL_WRITE_2(sc, sunscpal_icr, icr);
   
   #ifdef  SUNSCPAL_USE_BUS_DMA
           /*
            * XXX - this function is supposed to be independent of
            * the host's DMA implementation.
            */
    {
            sunscpal_dma_handle_t dh = sr->sr_dma_hand;
   
            /* sync the DMA map: */
            bus_dmamap_sync(sc->sunscpal_dmat, dh->dh_dmamap, 0, dh->dh_maplen,
                ((xs->xs_control & XS_CTL_DATA_OUT) == 0 ?
               BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE));
    }
   #endif /* SUNSCPAL_USE_BUS_DMA */
   
   
           if (icr & (SUNSCPAL_ICR_BUS_ERROR)) {
                   char buffer[64];
                   snprintb(buffer, sizeof(buffer), SUNSCPAL_ICR_BITS, icr);
                   printf("sc: DMA error, icr=%s, reset\n", buffer);
                   sr->sr_xs->error = XS_DRIVER_STUFFUP;
                   sc->sc_state |= SUNSCPAL_ABORTING;
                   goto out;
           }
   
           /* Note that timeout may have set the error flag. */
           if (sc->sc_state & SUNSCPAL_ABORTING)
                   goto out;
   
           /* XXX: Wait for DMA to actually finish? */
   
           /*
            * Now try to figure out how much actually transferred
            */
   
           resid = SUNSCPAL_DMA_COUNT_FLIP(SUNSCPAL_READ_2(sc,
               sunscpal_dma_count));
           ntrans = sc->sc_reqlen - resid;
   
   #ifdef  SUNSCPAL_DEBUG
           if (sunscpal_debug & SUNSCPAL_DBG_DMA) {
                   printf("%s: resid=0x%x ntrans=0x%x\n",
                       __func__, resid, ntrans);
           }
   #endif
   
           if (ntrans < sc->sc_min_dma_len) {
                   printf("sc: DMA count: 0x%x\n", resid);
                   sc->sc_state |= SUNSCPAL_ABORTING;
                   goto out;
           }
           if (ntrans > sc->sc_datalen)
                   panic("%s: excess transfer", __func__);
   
           /* Adjust data pointer */
           sc->sc_dataptr += ntrans;
           sc->sc_datalen -= ntrans;
   
           /*
            * After a read, we may need to clean-up
            * "Left-over bytes" (yuck!)
            */
           if (((xs->xs_control & XS_CTL_DATA_OUT) == 0) &&
               ((icr & SUNSCPAL_ICR_ODD_LENGTH) != 0)) {
   #ifdef DEBUG
                   printf("sc: Got Left-over bytes!\n");
   #endif
                   *(sc->sc_dataptr++) = SUNSCPAL_READ_1(sc, sunscpal_data);
                   sc->sc_datalen--;
           }
   
    out:
           SUNSCPAL_WRITE_2(sc, sunscpal_dma_count, SUNSCPAL_DMA_COUNT_FLIP(0));
   
   }
   
   /* Ask the target for a MSG_OUT phase. */
   static inline void
   sunscpal_sched_msgout(struct sunscpal_softc *sc, int msg_code)
   {
           /*
            * This controller does not allow you to assert ATN, which
            * will eventually leave us with no option other than to reset
            * the bus.  We keep this function as a placeholder, though,
            * and this printf will eventually go away or get #ifdef'ed:
            */
           printf("%s: trying to schedule 0x%0x\n", __func__, msg_code);
           sc->sc_msgpriq |= msg_code;
   }
   
   int
   sunscpal_pio_out(struct sunscpal_softc *sc, int phase, int count, uint8_t *data)
   {
           int resid;
   
           resid = count;
           while (resid > 0) {
                   if (!SUNSCPAL_BUSY(sc)) {
                           SUNSCPAL_TRACE("pio_out: lost BSY, resid=%d\n", resid);
                           break;
                   }
                   if (sunscpal_wait_req(sc)) {
                           SUNSCPAL_TRACE("pio_out: no REQ, resid=%d\n", resid);
                           break;
                   }
                   if (SUNSCPAL_BUS_PHASE(SUNSCPAL_READ_2(sc, sunscpal_icr)) !=
                       phase)
                           break;
   
                   /* Put the data on the bus. */
                   if (data) {
                           SUNSCPAL_BYTE_WRITE(sc, phase, *data++);
                   } else {
                           SUNSCPAL_BYTE_WRITE(sc, phase, 0);
                   }
   
                   --resid;
           }
   
           return count - resid;
   }
   
   
   int
   sunscpal_pio_in(struct sunscpal_softc *sc, int phase, int count, uint8_t *data)
   {
           int resid;
   
           resid = count;
           while (resid > 0) {
                   if (!SUNSCPAL_BUSY(sc)) {
                           SUNSCPAL_TRACE("pio_in: lost BSY, resid=%d\n", resid);
                           break;
                   }
                   if (sunscpal_wait_req(sc)) {
                           SUNSCPAL_TRACE("pio_in: no REQ, resid=%d\n", resid);
                           break;
                   }
                   /* A phase change is not valid until AFTER REQ rises! */
                   if (SUNSCPAL_BUS_PHASE(SUNSCPAL_READ_2(sc, sunscpal_icr)) !=
                       phase)
                           break;
   
                   /* Read the data bus. */
                   if (data)
                           *data++ = SUNSCPAL_BYTE_READ(sc, phase);
                   else
                           (void)SUNSCPAL_BYTE_READ(sc, phase);
   
                   --resid;
           }
   
           return count - resid;
   }
   
   
   void
   sunscpal_init(struct sunscpal_softc *sc)
   {
           int i, j;
   
   #ifdef  SUNSCPAL_DEBUG
           sunscpal_debug_sc = sc;
   #endif
   
           for (i = 0; i < SUNSCPAL_OPENINGS; i++)
                   sc->sc_ring[i].sr_xs = NULL;
           for (i = 0; i < 8; i++)
                   for (j = 0; j < 8; j++)
                           sc->sc_matrix[i][j] = NULL;
   
           sc->sc_prevphase = SUNSCPAL_PHASE_INVALID;
           sc->sc_state = SUNSCPAL_IDLE;
   
           SUNSCPAL_WRITE_2(sc, sunscpal_icr, 0);
           SUNSCPAL_WRITE_2(sc, sunscpal_dma_addr_h, 0);
           SUNSCPAL_WRITE_2(sc, sunscpal_dma_addr_l, 0);
           SUNSCPAL_WRITE_2(sc, sunscpal_dma_count, SUNSCPAL_DMA_COUNT_FLIP(0));
   
           SUNSCPAL_CLR_INTR(sc);
   
           /* Another hack (Er.. hook!) for anything that needs it: */
           if (sc->sc_intr_on) {
                   SUNSCPAL_TRACE("init: intr ON\n", 0);
                   sc->sc_intr_on(sc);
           }
   }
   
   
   static void
   sunscpal_reset_scsibus(struct sunscpal_softc *sc)
   {
   
           SUNSCPAL_TRACE("reset_scsibus, cur=0x%x\n", (long)sc->sc_current);
   
           SUNSCPAL_WRITE_2(sc, sunscpal_icr, SUNSCPAL_ICR_RESET);
           delay(500);
           SUNSCPAL_WRITE_2(sc, sunscpal_icr, 0);
   
           SUNSCPAL_CLR_INTR(sc);
           /* XXX - Need long delay here! */
           delay(100000);
   
           /* XXX - Need to cancel disconnected requests. */
   }
   
   
   /*
    * Interrupt handler for the SCSI Bus Controller (SBC)
    * This may also called for a DMA timeout (at splbio).
    */
   int
   sunscpal_intr(void *arg)
   {
           struct sunscpal_softc *sc = arg;
           int claimed = 0;
   
           /*
            * Do not touch SBC regs here unless sc_current == NULL
            * or it will complain about "register conflict" errors.
            * Instead, just let sunscpal_machine() deal with it.
            */
           SUNSCPAL_TRACE("intr: top, state=%d\n", sc->sc_state);
   
           if (sc->sc_state == SUNSCPAL_IDLE) {
                   /*
                    * Might be reselect.  sunscpal_reselect() will check,
                    * and set up the connection if so.  This will verify
                    * that sc_current == NULL at the beginning...
                    */
   
                   /* Another hack (Er.. hook!) for anything that needs it: */
                   if (sc->sc_intr_off) {
                           SUNSCPAL_TRACE("intr: for reselect, intr off\n", 0);
                       sc->sc_intr_off(sc);
                   }
   
                   sunscpal_reselect(sc);
           }
   
           /*
            * The remaining documented interrupt causes are a DMA complete
            * condition.
            *
            * The procedure is to let sunscpal_machine() figure out what
            * to do next.
            */
           if (sc->sc_state & SUNSCPAL_WORKING) {
                   SUNSCPAL_TRACE("intr: call machine, cur=0x%x\n",
                       (long)sc->sc_current);
                   /* This will usually free-up the nexus. */
                   sunscpal_machine(sc);
                   SUNSCPAL_TRACE("intr: machine done, cur=0x%x\n",
                       (long)sc->sc_current);
                   claimed = 1;
           }
   
           /* Maybe we can run some commands now... */
           if (sc->sc_state == SUNSCPAL_IDLE) {
                   SUNSCPAL_TRACE("intr: call sched, cur=0x%x\n",
                       (long)sc->sc_current);
                   sunscpal_sched(sc);
                   SUNSCPAL_TRACE("intr: sched done, cur=0x%x\n",
                       (long)sc->sc_current);
           }
   
           return claimed;
   }
   
   
   /*
    * Abort the current command (i.e. due to timeout)
    */
   void
   sunscpal_abort(struct sunscpal_softc *sc)
   {
   
           /*
            * Finish it now.  If DMA is in progress, we
            * can not call sunscpal_sched_msgout() because
            * that hits the SBC (avoid DMA conflict).
            */
   
           /* Another hack (Er.. hook!) for anything that needs it: */
           if (sc->sc_intr_off) {
                   SUNSCPAL_TRACE("abort: intr off\n", 0);
                   sc->sc_intr_off(sc);
           }
   
           sc->sc_state |= SUNSCPAL_ABORTING;
           if ((sc->sc_state & SUNSCPAL_DOINGDMA) == 0) {
                   sunscpal_sched_msgout(sc, SEND_ABORT);
           }
           SUNSCPAL_TRACE("abort: call machine, cur=0x%x\n",
               (long)sc->sc_current);
           sunscpal_machine(sc);
           SUNSCPAL_TRACE("abort: machine done, cur=0x%x\n",
               (long)sc->sc_current);
   
           /* Another hack (Er.. hook!) for anything that needs it: */
           if (sc->sc_intr_on) {
                   SUNSCPAL_TRACE("abort: intr ON\n", 0);
                   sc->sc_intr_on(sc);
           }
   }
   
   /*
    * Timeout handler, scheduled for each SCSI command.
    */
   void
   sunscpal_cmd_timeout(void *arg)
   {
           struct sunscpal_req *sr = arg;
           struct scsipi_xfer *xs;
           struct scsipi_periph *periph;
           struct sunscpal_softc *sc;
           int s;
   
           s = splbio();
   
           /* Get all our variables... */
           xs = sr->sr_xs;
           if (xs == NULL) {
                   printf("%s: no scsipi_xfer\n", __func__);
                   goto out;
           }
           periph = xs->xs_periph;
           sc = device_private(periph->periph_channel->chan_adapter->adapt_dev);
   
           printf("%s: cmd timeout, targ=%d, lun=%d\n",
               device_xname(sc->sc_dev),
               sr->sr_target, sr->sr_lun);
   
           /*
            * Mark the overdue job as failed, and arrange for
            * sunscpal_machine to terminate it.  If the victim
            * is the current job, call sunscpal_machine() now.
            * Otherwise arrange for sunscpal_sched() to do it.
            */
           sr->sr_flags |= SR_OVERDUE;
           if (sc->sc_current == sr) {
                   SUNSCPAL_TRACE("cmd_tmo: call abort, sr=0x%x\n", (long)sr);
                   sunscpal_abort(sc);
           } else {
                   /*
                    * The driver may be idle, or busy with another job.
                    * Arrange for sunscpal_sched() to do the deed.
                    */
                   SUNSCPAL_TRACE("cmd_tmo: clear matrix, t/l=0x%02x\n",
                       (sr->sr_target << 4) | sr->sr_lun);
                   sc->sc_matrix[sr->sr_target][sr->sr_lun] = NULL;
           }
   
           /*
            * We may have aborted the current job, or may have
            * already been idle. In either case, we should now
            * be idle, so try to start another job.
            */
           if (sc->sc_state == SUNSCPAL_IDLE) {
                   SUNSCPAL_TRACE("cmd_tmo: call sched, cur=0x%x\n",
                       (long)sc->sc_current);
                   sunscpal_sched(sc);
                   SUNSCPAL_TRACE("cmd_tmo: sched done, cur=0x%x\n",
                       (long)sc->sc_current);
           }
   
    out:
           splx(s);
   }
   
   
   /*****************************************************************
    * Interface to higher level
    *****************************************************************/
   
   
   /*
    * Enter a new SCSI command into the "issue" queue, and
    * if there is work to do, start it going.
    *
    * WARNING:  This can be called recursively!
    * (see comment in sunscpal_done)
    */
   void
   sunscpal_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t req,
       void *arg)
   {
           struct scsipi_xfer *xs;
           struct sunscpal_softc *sc;
           struct sunscpal_req *sr;
           int s, i, flags;
   
           sc = device_private(chan->chan_adapter->adapt_dev);
   
           switch (req) {
           case ADAPTER_REQ_RUN_XFER:
                   xs = arg;
                   flags = xs->xs_control;
   
                   if (flags & XS_CTL_DATA_UIO)
                           panic("sunscpal: scsi data uio requested");
   
                   s = splbio();
   
                   if (flags & XS_CTL_POLL) {
                           /* Terminate any current command. */
                           sr = sc->sc_current;
                           if (sr != NULL) {
                                   printf("%s: polled request aborting %d/%d\n",
                                       device_xname(sc->sc_dev), sr->sr_target,
                                       sr->sr_lun);
                                   sunscpal_abort(sc);
                           }
                           if (sc->sc_state != SUNSCPAL_IDLE) {
                                   panic("%s: polled request, abort failed",
                                       __func__);
                           }
                   }
   
                   /*
                    * Find lowest empty slot in ring buffer.
                    * XXX: What about "fairness" and cmd order?
                    */
                   for (i = 0; i < SUNSCPAL_OPENINGS; i++)
                           if (sc->sc_ring[i].sr_xs == NULL)
                                   goto new;
   
                   xs->error = XS_RESOURCE_SHORTAGE;
                   SUNSCPAL_TRACE("scsipi_cmd: no openings, rv=%d\n", rv);
                   goto out;
   
    new:
                   /* Create queue entry */
                   sr = &sc->sc_ring[i];
                   sr->sr_xs = xs;
                   sr->sr_target = xs->xs_periph->periph_target;
                   sr->sr_lun = xs->xs_periph->periph_lun;
                   sr->sr_dma_hand = NULL;
                   sr->sr_dataptr = xs->data;
                   sr->sr_datalen = xs->datalen;
                   sr->sr_flags = (flags & XS_CTL_POLL) ? SR_IMMED : 0;
                   sr->sr_status = -1;     /* no value */
                   sc->sc_ncmds++;
   
                   SUNSCPAL_TRACE("scsipi_cmd: new sr=0x%x\n", (long)sr);
   
                   if (flags & XS_CTL_POLL) {
                           /* Force this new command to be next. */
                           sc->sc_rr = i;
                   }
   
                   /*
                    * If we were idle, run some commands...
                    */
                   if (sc->sc_state == SUNSCPAL_IDLE) {
                           SUNSCPAL_TRACE("scsipi_cmd: call sched, cur=0x%x\n",
                               (long)sc->sc_current);
                           sunscpal_sched(sc);
                           SUNSCPAL_TRACE("scsipi_cmd: sched done, cur=0x%x\n",
                               (long)sc->sc_current);
                   }
   
                   if (flags & XS_CTL_POLL) {
                           /* Make sure sunscpal_sched() finished it. */
                           if ((xs->xs_status & XS_STS_DONE) == 0)
                                   panic("%s: poll didn't finish", __func__);
                   }
   
    out:
                   splx(s);
                   return;
   
           case ADAPTER_REQ_GROW_RESOURCES:
                   /* XXX Not supported. */
                   return;
   
           case ADAPTER_REQ_SET_XFER_MODE:
               {
                   /*
                    * We don't support Sync, Wide, or Tagged Queueing.
                    * Just callback now, to report this.
                    */
                   struct scsipi_xfer_mode *xm = arg;
   
                   xm->xm_mode = 0;
                   xm->xm_period = 0;
                   xm->xm_offset = 0;
                   scsipi_async_event(chan, ASYNC_EVENT_XFER_MODE, xm);
                   return;
               }
           }
   }
   
   
   /*
    * POST PROCESSING OF SCSI_CMD (usually current)
    * Called by sunscpal_sched(), sunscpal_machine()
    */
   static void
   sunscpal_done(struct sunscpal_softc *sc)
   {
           struct  sunscpal_req *sr;
           struct  scsipi_xfer *xs;
   
   #ifdef  DIAGNOSTIC
           if (sc->sc_state == SUNSCPAL_IDLE)
                   panic("%s: state=idle", __func__);
           if (sc->sc_current == NULL)
                   panic("%s: current=0", __func__);
   #endif
   
           sr = sc->sc_current;
           xs = sr->sr_xs;
   
           SUNSCPAL_TRACE("done: top, cur=0x%x\n", (long)sc->sc_current);
   
           /*
            * Clean up DMA resources for this command.
            */
           if (sr->sr_dma_hand) {
                   SUNSCPAL_TRACE("done: dma_free, dh=0x%x\n",
                       (long)sr->sr_dma_hand);
                   sunscpal_dma_free(sc);
           }
   #ifdef  DIAGNOSTIC
           if (sr->sr_dma_hand)
                   panic("%s: DMA free did not", __func__);
   #endif
   
           if (sc->sc_state & SUNSCPAL_ABORTING) {
                   SUNSCPAL_TRACE("done: aborting, error=%d\n", xs->error);
                   if (xs->error == XS_NOERROR)
                           xs->error = XS_TIMEOUT;
           }
   
           SUNSCPAL_TRACE("done: check error=%d\n", (long)xs->error);
   
           /* If error is already set, ignore sr_status value. */
           if (xs->error != XS_NOERROR)
                   goto finish;
   
           SUNSCPAL_TRACE("done: check status=%d\n", sr->sr_status);
   
           xs->status = sr->sr_status;
           switch (sr->sr_status) {
           case SCSI_OK:   /* 0 */
                   break;
   
           case SCSI_CHECK:
           case SCSI_BUSY:
                   xs->error = XS_BUSY;
                   break;
   
           case -1:
                   /* This is our "impossible" initial value. */
                   /* fallthrough */
           default:
                   printf("%s: target %d, bad status=%d\n",
                       device_xname(sc->sc_dev), sr->sr_target, sr->sr_status);
                   xs->error = XS_DRIVER_STUFFUP;
                   break;
           }
   
    finish:
   
           SUNSCPAL_TRACE("done: finish, error=%d\n", xs->error);
   
           /*
            * Dequeue the finished command, but don't clear sc_state until
            * after the call to scsipi_done(), because that may call back to
            * sunscpal_scsi_cmd() - unwanted recursion!
            *
            * Keeping sc->sc_state != idle terminates the recursion.
            */
   #ifdef  DIAGNOSTIC
           if ((sc->sc_state & SUNSCPAL_WORKING) == 0)
                   panic("%s: bad state", __func__);
   #endif
   
           /* Clear our pointers to the request. */
           sc->sc_current = NULL;
           sc->sc_matrix[sr->sr_target][sr->sr_lun] = NULL;
           callout_stop(&sr->sr_xs->xs_callout);
   
           /* Make the request free. */
           sr->sr_xs = NULL;
           sc->sc_ncmds--;
   
           /* Tell common SCSI code it is done. */
           scsipi_done(xs);
   
           sc->sc_state = SUNSCPAL_IDLE;
           /* Now sunscpal_sched() may be called again. */
   }
   
   
   /*
    * Schedule a SCSI operation.  This routine should return
    * only after it achieves one of the following conditions:
    *      Busy (sc->sc_state != SUNSCPAL_IDLE)
    *      No more work can be started.
    */
   static void
   sunscpal_sched(struct sunscpal_softc *sc)
   {
           struct sunscpal_req     *sr;
           struct scsipi_xfer *xs;
           int     target = 0, lun = 0;
           int     error, i;
   
           /* Another hack (Er.. hook!) for anything that needs it: */
           if (sc->sc_intr_off) {
                   SUNSCPAL_TRACE("sched: top, intr off\n", 0);
                   sc->sc_intr_off(sc);
           }
   
    next_job:
           /*
            * Grab the next job from queue.  Must be idle.
            */
   #ifdef  DIAGNOSTIC
           if (sc->sc_state != SUNSCPAL_IDLE)
                   panic("%s: not idle", __func__);
           if (sc->sc_current)
                   panic("%s: current set", __func__);
   #endif
   
           /*
            * Always start the search where we last looked.
            */
           i = sc->sc_rr;
           sr = NULL;
           do {
                   if (sc->sc_ring[i].sr_xs) {
                           target = sc->sc_ring[i].sr_target;
                           lun = sc->sc_ring[i].sr_lun;
                           if (sc->sc_matrix[target][lun] == NULL) {
                                   /*
                                    * Do not mark the  target/LUN busy yet,
                                    * because reselect may cause some other
                                    * job to become the current one, so we
                                    * might not actually start this job.
                                    * Instead, set sc_matrix later on.
                                    */
                                   sc->sc_rr = i;
                                   sr = &sc->sc_ring[i];
                                   break;
                           }
                   }
                   i++;
                   if (i == SUNSCPAL_OPENINGS)
                           i = 0;
           } while (i != sc->sc_rr);
   
           if (sr == NULL) {
                   SUNSCPAL_TRACE("sched: no work, cur=0x%x\n",
                       (long)sc->sc_current);
   
                   /* Another hack (Er.. hook!) for anything that needs it: */
                   if (sc->sc_intr_on) {
                          SUNSCPAL_TRACE("sched: ret, intr ON\n", 0);
                          sc->sc_intr_on(sc);
                  }
  
                  return;         /* No more work to do. */
          }
  
          SUNSCPAL_TRACE("sched: select for t/l=0x%02x\n",
              (sr->sr_target << 4) | sr->sr_lun);
  
          sc->sc_state = SUNSCPAL_WORKING;
          error = sunscpal_select(sc, sr);
          if (sc->sc_current) {
                  /* Lost the race!  reselected out from under us! */
                  /* Work with the reselected job. */
                  if (sr->sr_flags & SR_IMMED) {
                          printf("%s: reselected while polling (abort)\n",
                              device_xname(sc->sc_dev));
                          /* Abort the reselected job. */
                          sc->sc_state |= SUNSCPAL_ABORTING;
                          sc->sc_msgpriq |= SEND_ABORT;
                  }
                  sr = sc->sc_current;
                  xs = sr->sr_xs;
                  SUNSCPAL_TRACE("sched: reselect, new sr=0x%x\n", (long)sr);
                  goto have_nexus;
          }
  
          /* Normal selection result.  Target/LUN is now busy. */
          sc->sc_matrix[target][lun] = sr;
          sc->sc_current = sr;    /* connected */
          xs = sr->sr_xs;
  
          /*
           * Initialize pointers, etc. for this job
           */
          sc->sc_dataptr  = sr->sr_dataptr;
          sc->sc_datalen  = sr->sr_datalen;
          sc->sc_prevphase = SUNSCPAL_PHASE_INVALID;
          sc->sc_msgpriq = SEND_IDENTIFY;
          sc->sc_msgoutq = 0;
          sc->sc_msgout  = 0;
  
          SUNSCPAL_TRACE("sched: select rv=%d\n", error);
  
          switch (error) {
          case XS_NOERROR:
                  break;
  
          case XS_BUSY:
                  /* XXX - Reset and try again. */
                  printf("%s: select found SCSI bus busy, resetting...\n",
                      device_xname(sc->sc_dev));
                  sunscpal_reset_scsibus(sc);
                  /* fallthrough */
          case XS_SELTIMEOUT:
          default:
                  xs->error = error;      /* from select */
                  SUNSCPAL_TRACE("sched: call done, sr=0x%x\n", (long)sr);
                  sunscpal_done(sc);
  
                  /* Paranoia: clear everything. */
                  sc->sc_dataptr = NULL;
                  sc->sc_datalen = 0;
                  sc->sc_prevphase = SUNSCPAL_PHASE_INVALID;
                  sc->sc_msgpriq = 0;
                  sc->sc_msgoutq = 0;
                  sc->sc_msgout  = 0;
  
                  goto next_job;
          }
  
          /*
           * Selection was successful.  Normally, this means
           * we are starting a new command.  However, this
           * might be the termination of an overdue job.
           */
          if (sr->sr_flags & SR_OVERDUE) {
                  SUNSCPAL_TRACE("sched: overdue, sr=0x%x\n", (long)sr);
                  sc->sc_state |= SUNSCPAL_ABORTING;
                  sc->sc_msgpriq |= SEND_ABORT;
                  goto have_nexus;
          }
  
          /*
           * OK, we are starting a new command.
           * Initialize and allocate resources for the new command.
           * Device reset is special (only uses MSG_OUT phase).
           * Normal commands start in MSG_OUT phase where we will
           * send and IDENDIFY message, and then expect CMD phase.
           */
  #ifdef  SUNSCPAL_DEBUG
          if (sunscpal_debug & SUNSCPAL_DBG_CMDS) {
                  printf("%s: begin, target=%d, LUN=%d\n", __func__,
                      xs->xs_periph->periph_target, xs->xs_periph->periph_lun);
                  sunscpal_show_scsi_cmd(xs);
          }
  #endif
          if (xs->xs_control & XS_CTL_RESET) {
                  SUNSCPAL_TRACE("sched: cmd=reset, sr=0x%x\n", (long)sr);
                  /* Not an error, so do not set SUNSCPAL_ABORTING */
                  sc->sc_msgpriq |= SEND_DEV_RESET;
                  goto have_nexus;
          }
  
  #ifdef  DIAGNOSTIC
          if ((xs->xs_control & (XS_CTL_DATA_IN | XS_CTL_DATA_OUT)) == 0) {
                  if (sc->sc_dataptr) {
                          printf("%s: ptr but no data in/out flags?\n",
                              device_xname(sc->sc_dev));
                          SUNSCPAL_BREAK();
                          sc->sc_dataptr = NULL;
                  }
          }
  #endif
  
          /* Allocate DMA space (maybe) */
          if (sc->sc_dataptr && (sc->sc_flags & SUNSCPAL_DISABLE_DMA) == 0 &&
                  (sc->sc_datalen >= sc->sc_min_dma_len))
          {
                  SUNSCPAL_TRACE("sched: dma_alloc, len=%d\n", sc->sc_datalen);
                  sunscpal_dma_alloc(sc);
          }
  
          /*
           * Initialization hook called just after select,
           * at the beginning of COMMAND phase.
           * (but AFTER the DMA allocation is done)
           *
           * We need to set up the DMA engine BEFORE the target puts
           * the SCSI bus into any DATA phase.
           */
          if (sr->sr_dma_hand) {
                  SUNSCPAL_TRACE("sched: dma_setup, dh=0x%x\n",
                      (long) sr->sr_dma_hand);
              sunscpal_dma_setup(sc);
          }
  
          /*
           * Schedule a timeout for the job we are starting.
           */
          if ((sr->sr_flags & SR_IMMED) == 0) {
                  i = mstohz(xs->timeout);
                  SUNSCPAL_TRACE("sched: set timeout=%d\n", i);
                  callout_reset(&sr->sr_xs->xs_callout, i,
                      sunscpal_cmd_timeout, sr);
          }
  
   have_nexus:
  
          SUNSCPAL_TRACE("sched: call machine, cur=0x%x\n",
              (long)sc->sc_current);
          sunscpal_machine(sc);
          SUNSCPAL_TRACE("sched: machine done, cur=0x%x\n",
              (long)sc->sc_current);
  
          /*
           * What state did sunscpal_machine() leave us in?
           * Hopefully it sometimes completes a job...
           */
          if (sc->sc_state == SUNSCPAL_IDLE)
                  goto next_job;
  
          return;         /* Have work in progress. */
  }
  
  
  /*
   *  Reselect handler: checks for reselection, and if we are being
   *      reselected, it sets up sc->sc_current.
   *
   *  We are reselected when:
   *      SEL is TRUE
   *      IO  is TRUE
   *      BSY is FALSE
   */
  void
  sunscpal_reselect(struct sunscpal_softc *sc)
  {
  
          /*
           * This controller does not implement disconnect/reselect, so
           * we really don't have anything to do here.  We keep this
           * function as a placeholder, though.
           */
  }
  
  /*
   *  Select target: xs is the transfer that we are selecting for.
   *  sc->sc_current should be NULL.
   *
   *  Returns:
   *      sc->sc_current != NULL  ==> we were reselected (race!)
   *      XS_NOERROR              ==> selection worked
   *      XS_BUSY                 ==> lost arbitration
   *      XS_SELTIMEOUT           ==> no response to selection
   */
  static int
  sunscpal_select(struct sunscpal_softc *sc, struct sunscpal_req *sr)
  {
          int timo, target_mask;
          u_short mode;
  
          /* Check for reselect */
          sunscpal_reselect(sc);
          if (sc->sc_current) {
                  SUNSCPAL_TRACE("select: reselect, cur=0x%x\n",
                      (long)sc->sc_current);
                  return XS_BUSY; /* reselected */
          }
  
          /*
           * Select the target.
           */
          target_mask = (1 << sr->sr_target);
          SUNSCPAL_WRITE_1(sc, sunscpal_data, target_mask);
          SUNSCPAL_WRITE_2(sc, sunscpal_icr, SUNSCPAL_ICR_SELECT);
  
          /*
           * Wait for the target to assert BSY.
           * SCSI spec. says wait for 250 mS.
           */
          for (timo = 25000;;) {
                  if (SUNSCPAL_READ_2(sc, sunscpal_icr) & SUNSCPAL_ICR_BUSY)
                          goto success;
                  if (--timo <= 0)
                          break;
                  delay(10);
          }
  
          SUNSCPAL_WRITE_1(sc, sunscpal_data, 0);
          SUNSCPAL_WRITE_2(sc, sunscpal_icr, 0);
  
          SUNSCPAL_TRACE("select: device down, rc=%d\n", XS_SELTIMEOUT);
          return XS_SELTIMEOUT;
  
   success:
  
          /*
           * The target is now driving BSY, so we can stop
           * driving SEL and the data bus.  We do set up
           * whether or not this target needs parity.
           */
          mode = 0;
          if ((sc->sc_parity_disable & target_mask) == 0)
                  mode |= SUNSCPAL_ICR_PARITY_ENABLE;
          SUNSCPAL_WRITE_2(sc, sunscpal_icr, mode);
  
          return XS_NOERROR;
  }
  
  /*****************************************************************
   * Functions to handle each info. transfer phase:
   *****************************************************************/
  
  /*
   * The message system:
   *
   * This is a revamped message system that now should easier accommodate
   * new messages, if necessary.
   *
   * Currently we accept these messages:
   * IDENTIFY (when reselecting)
   * COMMAND COMPLETE # (expect bus free after messages marked #)
   * NOOP
   * MESSAGE REJECT
   * SYNCHRONOUS DATA TRANSFER REQUEST
   * SAVE DATA POINTER
   * RESTORE POINTERS
   * DISCONNECT #
   *
   * We may send these messages in prioritized order:
   * BUS DEVICE RESET #           if XS_CTL_RESET & xs->xs_control (or in
   *                              weird sits.)
   * MESSAGE PARITY ERROR         par. err. during MSGI
   * MESSAGE REJECT               If we get a message we don't know how to handle
   * ABORT #                      send on errors
   * INITIATOR DETECTED ERROR     also on errors (SCSI2) (during info xfer)
   * IDENTIFY                     At the start of each transfer
   * SYNCHRONOUS DATA TRANSFER REQUEST    if appropriate
   * NOOP                         if nothing else fits the bill ...
   */
  
  /*
   * Precondition:
   * The SCSI bus is already in the MSGI phase and there is a message byte
   * on the bus, along with an asserted REQ signal.
   *
   * Our return value determines whether our caller, sunscpal_machine()
   * will expect to see another REQ (and possibly phase change).
   */
  static int
  sunscpal_msg_in(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr = sc->sc_current;
          struct scsipi_xfer *xs = sr->sr_xs;
          int n, phase;
          int act_flags;
  
          act_flags = ACT_CONTINUE;
  
          if (sc->sc_prevphase == SUNSCPAL_PHASE_MSG_IN) {
                  /* This is a continuation of the previous message. */
                  n = sc->sc_imp - sc->sc_imess;
                  SUNSCPAL_TRACE("msg_in: continuation, n=%d\n", n);
                  goto nextbyte;
          }
  
          /* This is a new MESSAGE IN phase.  Clean up our state. */
          sc->sc_state &= ~SUNSCPAL_DROP_MSGIN;
  
   nextmsg:
          n = 0;
          sc->sc_imp = &sc->sc_imess[n];
  
   nextbyte:
          /*
           * Read a whole message, but don't ack the last byte.  If we reject the
           * message, we have to assert ATN during the message transfer phase
           * itself.
           */
          for (;;) {
                  /*
                   * Read a message byte.
                   * First, check BSY, REQ, phase...
                   */
                  if (!SUNSCPAL_BUSY(sc)) {
                          SUNSCPAL_TRACE("msg_in: lost BSY, n=%d\n", n);
                          /* XXX - Assume the command completed? */
                          act_flags |= (ACT_DISCONNECT | ACT_CMD_DONE);
                          return act_flags;
                  }
                  if (sunscpal_wait_req(sc)) {
                          SUNSCPAL_TRACE("msg_in: BSY but no REQ, n=%d\n", n);
                          /* Just let sunscpal_machine() handle it... */
                          return act_flags;
                  }
                  phase = SUNSCPAL_BUS_PHASE(SUNSCPAL_READ_2(sc, sunscpal_icr));
                  if (phase != SUNSCPAL_PHASE_MSG_IN) {
                          /*
                           * Target left MESSAGE IN, probably because it
                           * a) noticed our ATN signal, or
                           * b) ran out of messages.
                           */
                          return act_flags;
                  }
                  /* Still in MESSAGE IN phase, and REQ is asserted. */
                  if ((SUNSCPAL_READ_2(sc, sunscpal_icr) &
                      SUNSCPAL_ICR_PARITY_ERROR) != 0) {
                          sunscpal_sched_msgout(sc, SEND_PARITY_ERROR);
                          sc->sc_state |= SUNSCPAL_DROP_MSGIN;
                  }
  
                  /* Gather incoming message bytes if needed. */
                  if ((sc->sc_state & SUNSCPAL_DROP_MSGIN) == 0) {
                          if (n >= SUNSCPAL_MAX_MSG_LEN) {
                                  sunscpal_sched_msgout(sc, SEND_REJECT);
                                  sc->sc_state |= SUNSCPAL_DROP_MSGIN;
                          } else {
                                  *sc->sc_imp++ =
                                      SUNSCPAL_READ_1(sc, sunscpal_cmd_stat);
                                  n++;
                                  /*
                                   * This testing is suboptimal, but most
                                   * messages will be of the one byte variety, so
                                   * it should not affect performance
                                   * significantly.
                                   */
                                  if (n == 1 && MSG_IS1BYTE(sc->sc_imess[0]))
                                          goto have_msg;
                                  if (n == 2 && MSG_IS2BYTE(sc->sc_imess[0]))
                                          goto have_msg;
                                  if (n >= 3 && MSG_ISEXTENDED(sc->sc_imess[0]) &&
                                          n == sc->sc_imess[1] + 2)
                                          goto have_msg;
                          }
                  }
  
                  /*
                   * If we reach this spot we're either:
                   * a) in the middle of a multi-byte message, or
                   * b) dropping bytes.
                   */
  
                  if (act_flags != ACT_CONTINUE)
                          return act_flags;
  
                  /* back to nextbyte */
          }
  
   have_msg:
          /* We now have a complete message.  Parse it. */
  
          switch (sc->sc_imess[0]) {
          case MSG_CMDCOMPLETE:
                  SUNSCPAL_TRACE("msg_in: CMDCOMPLETE\n", 0);
                  /* Target is about to disconnect. */
                  act_flags |= (ACT_DISCONNECT | ACT_CMD_DONE);
                  break;
  
          case MSG_PARITY_ERROR:
                  SUNSCPAL_TRACE("msg_in: PARITY_ERROR\n", 0);
                  /* Resend the last message. */
                  sunscpal_sched_msgout(sc, sc->sc_msgout);
                  break;
  
          case MSG_MESSAGE_REJECT:
                  /* The target rejects the last message we sent. */
                  SUNSCPAL_TRACE("msg_in: got reject for 0x%x\n", sc->sc_msgout);
                  switch (sc->sc_msgout) {
                  case SEND_IDENTIFY:
                          /* Really old target controller? */
                          /* XXX ... */
                          break;
                  case SEND_INIT_DET_ERR:
                          goto abort;
                  }
                  break;
  
          case MSG_NOOP:
                  SUNSCPAL_TRACE("msg_in: NOOP\n", 0);
                  break;
  
          case MSG_DISCONNECT:
                  SUNSCPAL_TRACE("msg_in: DISCONNECT\n", 0);
                  /* Target is about to disconnect. */
                  act_flags |= ACT_DISCONNECT;
                  if ((xs->xs_periph->periph_quirks & PQUIRK_AUTOSAVE) == 0)
                          break;
                  /*FALLTHROUGH*/
  
          case MSG_SAVEDATAPOINTER:
                  SUNSCPAL_TRACE("msg_in: SAVE_PTRS\n", 0);
                  sr->sr_dataptr = sc->sc_dataptr;
                  sr->sr_datalen = sc->sc_datalen;
                  break;
  
          case MSG_RESTOREPOINTERS:
                  SUNSCPAL_TRACE("msg_in: RESTORE_PTRS\n", 0);
                  sc->sc_dataptr = sr->sr_dataptr;
                  sc->sc_datalen = sr->sr_datalen;
                  break;
  
          case MSG_EXTENDED:
                  switch (sc->sc_imess[2]) {
                  case MSG_EXT_SDTR:
                  case MSG_EXT_WDTR:
                          /* This controller can not do synchronous mode. */
                          goto reject;
                  default:
                          printf("%s: unrecognized MESSAGE EXTENDED; "
                              "sending REJECT\n",
                              device_xname(sc->sc_dev));
                          SUNSCPAL_BREAK();
                          goto reject;
                  }
                  break;
  
          default:
                  SUNSCPAL_TRACE("msg_in: eh? imsg=0x%x\n", sc->sc_imess[0]);
                  printf("%s: unrecognized MESSAGE; sending REJECT\n",
                      device_xname(sc->sc_dev));
                  SUNSCPAL_BREAK();
                  /* FALLTHROUGH */
          reject:
                  sunscpal_sched_msgout(sc, SEND_REJECT);
                  break;
  
          abort:
                  sc->sc_state |= SUNSCPAL_ABORTING;
                  sunscpal_sched_msgout(sc, SEND_ABORT);
                  break;
          }
  
          /* Go get the next message, if any. */
          if (act_flags == ACT_CONTINUE)
                  goto nextmsg;
  
          return act_flags;
  }
  
  
  /*
   * The message out (and in) stuff is a bit complicated:
   * If the target requests another message (sequence) without
   * having changed phase in between it really asks for a
   * retransmit, probably due to parity error(s).
   * The following messages can be sent:
   * IDENTIFY        @ These 4 stem from SCSI command activity
   * SDTR            @
   * WDTR            @
   * DEV_RESET       @
   * REJECT if MSGI doesn't make sense
   * PARITY_ERROR if parity error while in MSGI
   * INIT_DET_ERR if parity error while not in MSGI
   * ABORT if INIT_DET_ERR rejected
   * NOOP if asked for a message and there's nothing to send
   *
   * Note that we call this one with (sc_current == NULL)
   * when sending ABORT for unwanted reselections.
   */
  static int
  sunscpal_msg_out(struct sunscpal_softc *sc)
  {
          /*
           * This controller does not allow you to assert ATN, which
           * means we will never get the opportunity to send messages to
           * the target (the bus will never enter this MSG_OUT phase).
           * This will eventually leave us with no option other than to
           * reset the bus.  We keep this function as a placeholder,
           * though, and this printf will eventually go away or get
           * #ifdef'ed:
           */
          printf("%s: bus is in MSG_OUT phase?\n", __func__);
          return ACT_CONTINUE | ACT_RESET_BUS;
  }
  
  /*
   * Handle command phase.
   */
  static int
  sunscpal_command(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr = sc->sc_current;
          struct scsipi_xfer *xs = sr->sr_xs;
          int len;
  
          /* Assume command can be sent in one go. */
          /* XXX: Do this using DMA, and get a phase change intr? */
          len = sunscpal_pio_out(sc, SUNSCPAL_PHASE_COMMAND, xs->cmdlen,
              (uint8_t *)xs->cmd);
  
          if (len != xs->cmdlen) {
  #ifdef  SUNSCPAL_DEBUG
                  printf("%s: short transfer: wanted %d got %d.\n",
                      __func__, xs->cmdlen, len);
                  sunscpal_show_scsi_cmd(xs);
                  SUNSCPAL_BREAK();
  #endif
                  if (len < 6) {
                          xs->error = XS_DRIVER_STUFFUP;
                          sc->sc_state |= SUNSCPAL_ABORTING;
                          sunscpal_sched_msgout(sc, SEND_ABORT);
                  }
  
          }
  
          return ACT_CONTINUE;
  }
  
  
  /*
   * Handle either data_in or data_out
   */
  static int
  sunscpal_data_xfer(struct sunscpal_softc *sc, int phase)
  {
          struct sunscpal_req *sr = sc->sc_current;
          struct scsipi_xfer *xs = sr->sr_xs;
          int expected_phase;
          int len;
  
          /*
           * When aborting a command, disallow any data phase.
           */
          if (sc->sc_state & SUNSCPAL_ABORTING) {
                  printf("%s: aborting, bus phase=%s (reset)\n",
                      device_xname(sc->sc_dev), phase_names[(phase >> 8) & 7]);
                  return ACT_RESET_BUS;   /* XXX */
          }
  
          /* Validate expected phase (data_in or data_out) */
          expected_phase = (xs->xs_control & XS_CTL_DATA_OUT) ?
              SUNSCPAL_PHASE_DATA_OUT : SUNSCPAL_PHASE_DATA_IN;
          if (phase != expected_phase) {
                  printf("%s: data phase error\n", device_xname(sc->sc_dev));
                  goto abort;
          }
  
          /* Make sure we have some data to move. */
          if (sc->sc_datalen <= 0) {
                  /* Device needs padding. */
                  if (phase == SUNSCPAL_PHASE_DATA_IN)
                          sunscpal_pio_in(sc, phase, 4096, NULL);
                  else
                          sunscpal_pio_out(sc, phase, 4096, NULL);
                  /* Make sure that caused a phase change. */
                  if (SUNSCPAL_BUS_PHASE(SUNSCPAL_READ_2(sc, sunscpal_icr)) ==
                      phase) {
                          /* More than 4k is just too much! */
                          printf("%s: too much data padding\n",
                              device_xname(sc->sc_dev));
                          goto abort;
                  }
                  return ACT_CONTINUE;
          }
  
          /*
           * Attempt DMA only if dma_alloc gave us a DMA handle AND
           * there is enough left to transfer so DMA is worth while.
           */
          if (sr->sr_dma_hand && (sc->sc_datalen >= sc->sc_min_dma_len)) {
                  /*
                   * OK, really start DMA.  Note, the MD start function
                   * is responsible for setting the TCMD register, etc.
                   * (Acknowledge the phase change there, not here.)
                   */
                  SUNSCPAL_TRACE("data_xfer: dma_start, dh=0x%x\n",
                      (long)sr->sr_dma_hand);
                  sunscpal_dma_start(sc);
                  return ACT_WAIT_DMA;
          }
  
          /*
           * Doing PIO for data transfer.  (Possibly "Pseudo DMA")
           * XXX:  Do PDMA functions need to set tcmd later?
           */
          SUNSCPAL_TRACE("data_xfer: doing PIO, len=%d\n", sc->sc_datalen);
          if (phase == SUNSCPAL_PHASE_DATA_OUT) {
                  len = sunscpal_pio_out(sc, phase,
                      sc->sc_datalen, sc->sc_dataptr);
          } else {
                  len = sunscpal_pio_in(sc, phase,
                      sc->sc_datalen, sc->sc_dataptr);
          }
          sc->sc_dataptr += len;
          sc->sc_datalen -= len;
  
          SUNSCPAL_TRACE("data_xfer: did PIO, resid=%d\n", sc->sc_datalen);
          return ACT_CONTINUE;
  
   abort:
          sc->sc_state |= SUNSCPAL_ABORTING;
          sunscpal_sched_msgout(sc, SEND_ABORT);
          return ACT_CONTINUE;
  }
  
  
  static int
  sunscpal_status(struct sunscpal_softc *sc)
  {
          int len;
          uint8_t status;
          struct sunscpal_req *sr = sc->sc_current;
  
          len = sunscpal_pio_in(sc, SUNSCPAL_PHASE_STATUS, 1, &status);
          if (len) {
                  sr->sr_status = status;
          } else {
                  printf("%s: none?\n", __func__);
          }
  
          return ACT_CONTINUE;
  }
  
  
  /*
   * This is the big state machine that follows SCSI phase changes.
   * This is somewhat like a co-routine.  It will do a SCSI command,
   * and exit if the command is complete, or if it must wait, i.e.
   * for DMA to complete or for reselect to resume the job.
   *
   * The bus must be selected, and we need to know which command is
   * being undertaken.
   */
  static void
  sunscpal_machine(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr;
          struct scsipi_xfer *xs;
          int act_flags, phase, timo;
  
  #ifdef  DIAGNOSTIC
          if (sc->sc_state == SUNSCPAL_IDLE)
                  panic("%s: state=idle", __func__);
          if (sc->sc_current == NULL)
                  panic("%s: no current cmd", __func__);
  #endif
  
          sr = sc->sc_current;
          xs = sr->sr_xs;
          act_flags = ACT_CONTINUE;
  
          /*
           * This will be called by sunscpal_intr() when DMA is
           * complete.  Must stop DMA before touching the PAL or
           * there will be "register conflict" errors.
           */
          if ((sc->sc_state & SUNSCPAL_DOINGDMA) != 0) {
                  /* Pick-up where where we left off... */
                  goto dma_done;
          }
  
   next_phase:
  
          if (!SUNSCPAL_BUSY(sc)) {
                  /* Unexpected disconnect */
                  printf("%s: unexpected disconnect.\n", __func__);
                  xs->error = XS_DRIVER_STUFFUP;
                  act_flags |= (ACT_DISCONNECT | ACT_CMD_DONE);
                  goto do_actions;
          }
  
          /*
           * Wait for REQ before reading the phase.
           * Need to wait longer than usual here, because
           * some devices are just plain slow...
           */
          timo = sunscpal_wait_phase_timo;
          for (;;) {
                  if (SUNSCPAL_READ_2(sc, sunscpal_icr) & SUNSCPAL_ICR_REQUEST)
                          break;
                  if (--timo <= 0) {
                          if (sc->sc_state & SUNSCPAL_ABORTING) {
                                  printf("%s: no REQ while aborting, reset\n",
                                      device_xname(sc->sc_dev));
                                  act_flags |= ACT_RESET_BUS;
                                  goto do_actions;
                          }
                          printf("%s: no REQ for next phase, abort\n",
                              device_xname(sc->sc_dev));
                          sc->sc_state |= SUNSCPAL_ABORTING;
                          sunscpal_sched_msgout(sc, SEND_ABORT);
                          goto next_phase;
                  }
                  delay(100);
          }
  
          phase = SUNSCPAL_BUS_PHASE(SUNSCPAL_READ_2(sc, sunscpal_icr));
          SUNSCPAL_TRACE("machine: phase=%s\n",
              (long)phase_names[(phase >> 8) & 7]);
  
          /*
           * We assume that the device knows what it's doing,
           * so any phase is good.
           */
  
          switch (phase) {
  
          case SUNSCPAL_PHASE_DATA_OUT:
          case SUNSCPAL_PHASE_DATA_IN:
                  act_flags = sunscpal_data_xfer(sc, phase);
                  break;
  
          case SUNSCPAL_PHASE_COMMAND:
                  act_flags = sunscpal_command(sc);
                  break;
  
          case SUNSCPAL_PHASE_STATUS:
                  act_flags = sunscpal_status(sc);
                  break;
  
          case SUNSCPAL_PHASE_MSG_OUT:
                  act_flags = sunscpal_msg_out(sc);
                  break;
  
          case SUNSCPAL_PHASE_MSG_IN:
                  act_flags = sunscpal_msg_in(sc);
                  break;
  
          default:
                  printf("%s: Unexpected phase 0x%x\n", __func__, phase);
                  sc->sc_state |= SUNSCPAL_ABORTING;
                  sunscpal_sched_msgout(sc, SEND_ABORT);
                  goto next_phase;
  
          } /* switch */
          sc->sc_prevphase = phase;
  
   do_actions:
  
          if (act_flags & ACT_WAIT_DMA) {
                  act_flags &= ~ACT_WAIT_DMA;
                  /* Wait for DMA to complete (polling, or interrupt). */
                  if ((sr->sr_flags & SR_IMMED) == 0) {
                          SUNSCPAL_TRACE("machine: wait for DMA intr.\n", 0);
                          return;         /* will resume at dma_done */
                  }
                  /* Busy-wait for it to finish. */
                  SUNSCPAL_TRACE("machine: dma_poll, dh=0x%x\n",
                      (long)sr->sr_dma_hand);
                  sunscpal_dma_poll(sc);
   dma_done:
                  /* Return here after interrupt. */
                  if (sr->sr_flags & SR_OVERDUE)
                          sc->sc_state |= SUNSCPAL_ABORTING;
                  SUNSCPAL_TRACE("machine: dma_stop, dh=0x%x\n",
                      (long)sr->sr_dma_hand);
                  sunscpal_dma_stop(sc);
                  SUNSCPAL_CLR_INTR(sc);  /* XXX */
                  /*
                   * While DMA is running we can not touch the SBC,
                   * so various places just set SUNSCPAL_ABORTING and
                   * expect us the "kick it" when DMA is done.
                   */
                  if (sc->sc_state & SUNSCPAL_ABORTING) {
                          sunscpal_sched_msgout(sc, SEND_ABORT);
                  }
          }
  
          /*
           * Check for parity error.
           * XXX - better place to check?
           */
          if (SUNSCPAL_READ_2(sc, sunscpal_icr) & SUNSCPAL_ICR_PARITY_ERROR) {
                  printf("%s: parity error!\n", device_xname(sc->sc_dev));
                  /* XXX: sc->sc_state |= SUNSCPAL_ABORTING; */
                  sunscpal_sched_msgout(sc, SEND_PARITY_ERROR);
          }
  
          if (act_flags == ACT_CONTINUE)
                  goto next_phase;
          /* All other actions "break" from the loop. */
  
          SUNSCPAL_TRACE("machine: act_flags=0x%x\n", act_flags);
  
          if (act_flags & ACT_RESET_BUS) {
                  act_flags |= ACT_CMD_DONE;
                  /*
                   * Reset the SCSI bus, usually due to a timeout.
                   * The error code XS_TIMEOUT allows retries.
                   */
                  sc->sc_state |= SUNSCPAL_ABORTING;
                  printf("%s: reset SCSI bus for TID=%d LUN=%d\n",
                      device_xname(sc->sc_dev), sr->sr_target, sr->sr_lun);
                  sunscpal_reset_scsibus(sc);
          }
  
          if (act_flags & ACT_CMD_DONE) {
                  act_flags |= ACT_DISCONNECT;
                  /* Need to call scsipi_done() */
                  /* XXX: from the aic6360 driver, but why? */
                  if (sc->sc_datalen < 0) {
                          printf("%s: %d extra bytes from %d:%d\n",
                              device_xname(sc->sc_dev), -sc->sc_datalen,
                              sr->sr_target, sr->sr_lun);
                          sc->sc_datalen = 0;
                  }
                  xs->resid = sc->sc_datalen;
                  /* Note: this will clear sc_current */
                  SUNSCPAL_TRACE("machine: call done, cur=0x%x\n", (long)sr);
                  sunscpal_done(sc);
          }
  
          if (act_flags & ACT_DISCONNECT) {
                  /*
                   * The device has dropped BSY (or will soon).
                   * We have to wait here for BSY to drop, otherwise
                   * the next command may decide we need a bus reset.
                   */
                  timo = sunscpal_wait_req_timo;  /* XXX */
                  for (;;) {
                          if (!SUNSCPAL_BUSY(sc))
                                  goto busfree;
                          if (--timo <= 0)
                                  break;
                          delay(2);
                  }
                  /* Device is sitting on the bus! */
                  printf("%s: Target %d LUN %d stuck busy, resetting...\n",
                      device_xname(sc->sc_dev), sr->sr_target, sr->sr_lun);
                  sunscpal_reset_scsibus(sc);
   busfree:
                  SUNSCPAL_TRACE("machine: discon, waited %d\n",
                          sunscpal_wait_req_timo - timo);
  
                  SUNSCPAL_WRITE_2(sc, sunscpal_icr, 0);
  
                  if ((act_flags & ACT_CMD_DONE) == 0) {
                          SUNSCPAL_TRACE("machine: discon, cur=0x%x\n", (long)sr);
                  }
  
                  /*
                   * We may be here due to a disconnect message,
                   * in which case we did NOT call sunscpal_done,
                   * and we need to clear sc_current.
                   */
                  sc->sc_state = SUNSCPAL_IDLE;
                  sc->sc_current = NULL;
  
                  /* Paranoia: clear everything. */
                  sc->sc_dataptr = NULL;
                  sc->sc_datalen = 0;
                  sc->sc_prevphase = SUNSCPAL_PHASE_INVALID;
                  sc->sc_msgpriq = 0;
                  sc->sc_msgoutq = 0;
                  sc->sc_msgout  = 0;
  
                  /* Our caller will re-enable interrupts. */
          }
  }
  
  
  #ifdef  SUNSCPAL_DEBUG
  
  static void
  sunscpal_show_scsi_cmd(struct scsipi_xfer *xs)
  {
          uint8_t *b = (uint8_t *)xs->cmd;
          int i = 0;
  
          scsipi_printaddr(xs->xs_periph);
          if ((xs->xs_control & XS_CTL_RESET) == 0) {
                  printf("-");
                  while (i < xs->cmdlen) {
                          if (i != 0)
                                  printf(",");
                          printf("%x", b[i++]);
                  }
                  printf("-\n");
          } else {
                  printf("-RESET-\n");
          }
  }
  
  
  int sunscpal_traceidx = 0;
  
  #define TRACE_MAX       1024
  struct trace_ent {
          char *msg;
          long  val;
  } sunscpal_tracebuf[TRACE_MAX];
  
  void
  sunscpal_trace(char *msg, long val)
  {
          struct trace_ent *tr;
          int s;
  
          s = splbio();
  
          tr = &sunscpal_tracebuf[sunscpal_traceidx];
  
          sunscpal_traceidx++;
          if (sunscpal_traceidx >= TRACE_MAX)
                  sunscpal_traceidx = 0;
  
          tr->msg = msg;
          tr->val = val;
  
          splx(s);
  }
  
  #ifdef  DDB
  void
  sunscpal_clear_trace(void)
  {
  
          sunscpal_traceidx = 0;
          memset((void *)sunscpal_tracebuf, 0, sizeof(sunscpal_tracebuf));
  }
  
  void
  sunscpal_show_trace(void)
  {
          struct trace_ent *tr;
          int idx;
  
          idx = sunscpal_traceidx;
          do {
                  tr = &sunscpal_tracebuf[idx];
                  idx++;
                  if (idx >= TRACE_MAX)
                          idx = 0;
                  if (tr->msg)
                          db_printf(tr->msg, tr->val);
          } while (idx != sunscpal_traceidx);
  }
  
  void
  sunscpal_show_req(struct sunscpal_req *sr)
  {
          struct scsipi_xfer *xs = sr->sr_xs;
  
          db_printf("TID=%d ",    sr->sr_target);
          db_printf("LUN=%d ",    sr->sr_lun);
          db_printf("dh=%p ",     sr->sr_dma_hand);
          db_printf("dptr=%p ",   sr->sr_dataptr);
          db_printf("dlen=0x%x ", sr->sr_datalen);
          db_printf("flags=%d ",  sr->sr_flags);
          db_printf("stat=%d ",   sr->sr_status);
  
          if (xs == NULL) {
                  db_printf("(xs=NULL)\n");
                  return;
          }
          db_printf("\n");
  #ifdef  SCSIDEBUG
          show_scsipi_xs(xs);
  #else
          db_printf("xs=%p\n", xs);
  #endif
  }
  
  void
  sunscpal_show_state(void)
  {
          struct sunscpal_softc *sc;
          struct sunscpal_req *sr;
          int i, j, k;
  
          sc = sunscpal_debug_sc;
  
          if (sc == NULL) {
                  db_printf("sunscpal_debug_sc == NULL\n");
                  return;
          }
  
          db_printf("sc_ncmds=%d\n",      sc->sc_ncmds);
          k = -1; /* which is current? */
          for (i = 0; i < SUNSCPAL_OPENINGS; i++) {
                  sr = &sc->sc_ring[i];
                  if (sr->sr_xs) {
                          if (sr == sc->sc_current)
                                  k = i;
                          db_printf("req %d: (sr=%p)", i, sr);
                          sunscpal_show_req(sr);
                  }
          }
          db_printf("sc_rr=%d, current=%d\n", sc->sc_rr, k);
  
          db_printf("Active request matrix:\n");
          for(i = 0; i < 8; i++) {                /* targets */
                  for (j = 0; j < 8; j++) {       /* LUN */
                          sr = sc->sc_matrix[i][j];
                          if (sr) {
                                  db_printf("TID=%d LUN=%d sr=%p\n", i, j, sr);
                          }
                  }
          }
  
          db_printf("sc_state=0x%x\n",    sc->sc_state);
          db_printf("sc_current=%p\n",    sc->sc_current);
          db_printf("sc_dataptr=%p\n",    sc->sc_dataptr);
          db_printf("sc_datalen=0x%x\n",  sc->sc_datalen);
  
          db_printf("sc_prevphase=%d\n",  sc->sc_prevphase);
          db_printf("sc_msgpriq=0x%x\n",  sc->sc_msgpriq);
  }
  #endif  /* DDB */
  #endif  /* SUNSCPAL_DEBUG */
  
  void
  sunscpal_attach(struct sunscpal_softc *sc, int options)
  {
  
          /*
           * Handle our options.
           */
          aprint_normal(": options=0x%x\n", options);
          sc->sc_parity_disable = (options & SUNSCPAL_OPT_NO_PARITY_CHK);
          if (options & SUNSCPAL_OPT_DISABLE_DMA)
                  sc->sc_flags |= SUNSCPAL_DISABLE_DMA;
  
          /*
           * Fill in the adapter.
           */
          memset(&sc->sc_adapter, 0, sizeof(sc->sc_adapter));
          sc->sc_adapter.adapt_dev = sc->sc_dev;
          sc->sc_adapter.adapt_nchannels = 1;
          sc->sc_adapter.adapt_openings = SUNSCPAL_OPENINGS;
          sc->sc_adapter.adapt_max_periph = 1;
          sc->sc_adapter.adapt_request = sunscpal_scsipi_request;
          sc->sc_adapter.adapt_minphys = sunscpal_minphys;
          if (options & SUNSCPAL_OPT_FORCE_POLLING)
                  sc->sc_adapter.adapt_flags |= SCSIPI_ADAPT_POLL_ONLY;
  
          sc->sc_channel.chan_adapter = &sc->sc_adapter;
          sc->sc_channel.chan_bustype = &scsi_bustype;
          sc->sc_channel.chan_channel = 0;
          sc->sc_channel.chan_ntargets = 8;
          sc->sc_channel.chan_nluns = 8;
          sc->sc_channel.chan_id = 7;
  
          /*
           * Add reference to adapter so that we drop the reference after
           * config_found() to make sure the adapter is disabled.
           */
          if (scsipi_adapter_addref(&sc->sc_adapter) != 0) {
                  aprint_error_dev(sc->sc_dev, "unable to enable controller\n");
                  return;
          }
  
          sunscpal_init(sc);      /* Init chip and driver */
          sunscpal_reset_scsibus(sc);
  
          /*
           * Ask the adapter what subunits are present
           */
          (void)config_found(sc->sc_dev, &sc->sc_channel, scsiprint, CFARGS_NONE);
          scsipi_adapter_delref(&sc->sc_adapter);
  }
  
  int
  sunscpal_detach(struct sunscpal_softc *sc, int flags)
  {
  
          return EOPNOTSUPP;
  }
  
  static void
  sunscpal_minphys(struct buf *bp)
  {
  
          if (bp->b_bcount > SUNSCPAL_MAX_DMA_LEN) {
  #ifdef  SUNSCPAL_DEBUG
                  if (sunscpal_debug & SUNSCPAL_DBG_DMA) {
                          printf("%s: len = 0x%lx.\n", __func__, bp->b_bcount);
                          Debugger();
                  }
  #endif
                  bp->b_bcount = SUNSCPAL_MAX_DMA_LEN;
          }
          return minphys(bp);
  }
  
  #ifdef SUNSCPAL_USE_BUS_DMA
  
  /*
   * Allocate a DMA handle and put it in sr->sr_dma_hand.  Prepare
   * for DMA transfer.
   */
  static void
  sunscpal_dma_alloc(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr = sc->sc_current;
          sunscpal_dma_handle_t 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)sc->sc_dataptr;
          xlen = 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 < sc->sc_min_dma_len)
                  panic("%s: xlen=0x%x", __func__, xlen);
  
          /*
           * Never attempt single transfers of more than 63k, because
           * our count register is only 16 bits.
           * This should never happen since already bounded by minphys().
           * XXX - Should just segment these...
           */
          if (xlen > SUNSCPAL_MAX_DMA_LEN) {
                  printf("%s: excessive xlen=0x%x\n", __func__, xlen);
                  Debugger();
                  sc->sc_datalen = xlen = SUNSCPAL_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 < SUNSCPAL_OPENINGS; i++) {
                  if ((sc->sc_dma_handles[i].dh_flags & SUNSCDH_BUSY) == 0)
                          goto found;
          }
          panic("%s: no free DMA handles.", device_xname(sc->sc_dev));
   found:
  
          dh = &sc->sc_dma_handles[i];
          dh->dh_flags = SUNSCDH_BUSY;
          dh->dh_mapaddr = (uint8_t *)addr;
          dh->dh_maplen  = xlen;
          dh->dh_dvma = 0;
  
          /* Load the DMA map. */
          if (bus_dmamap_load(sc->sunscpal_dmat, dh->dh_dmamap,
              dh->dh_mapaddr, dh->dh_maplen, NULL, BUS_DMA_NOWAIT) != 0) {
                  /* Can't load map */
                  printf("%s: can't DMA %p/0x%x\n", __func__,
                      dh->dh_mapaddr, dh->dh_maplen);
                  dh->dh_flags = 0;
                  return;
          }
  
          /* success */
          sr->sr_dma_hand = dh;
  }
  
  static void
  sunscpal_dma_free(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr = sc->sc_current;
          sunscpal_dma_handle_t dh = sr->sr_dma_hand;
  
  #ifdef  DIAGNOSTIC
          if (dh == NULL)
                  panic("%s: no DMA handle", __func__);
  #endif
  
          if (sc->sc_state & SUNSCPAL_DOINGDMA)
                  panic("%s: free while in progress", __func__);
  
          if (dh->dh_flags & SUNSCDH_BUSY) {
                  /* XXX - Should separate allocation and mapping. */
                  /* Give back the DVMA space. */
                  bus_dmamap_unload(sc->sunscpal_dmat, dh->dh_dmamap);
                  dh->dh_flags = 0;
          }
          sr->sr_dma_hand = NULL;
  }
  
  /*
   * This function is called during the SELECT phase that
   * precedes a COMMAND phase, in case we need to setup the
   * DMA engine before the bus enters a DATA phase.
   *
   * On the sc version, setup the start address and the count.
   */
  static void
  sunscpal_dma_setup(struct sunscpal_softc *sc)
  {
          struct sunscpal_req *sr = sc->sc_current;
          struct scsipi_xfer *xs = sr->sr_xs;
          sunscpal_dma_handle_t dh = sr->sr_dma_hand;
          long data_pa;
          int xlen;
  
          /*
           * Get the DVMA mapping for this segment.
           * XXX - Should separate allocation and mapin.
           */
          data_pa = dh->dh_dvma;
          data_pa += (sc->sc_dataptr - dh->dh_mapaddr);
          if (data_pa & 1)
                  panic("%s: bad pa=0x%lx", __func__, data_pa);
          xlen = sc->sc_datalen;
          if (xlen & 1)
                  panic("%s: bad xlen=0x%x", __func__, xlen);
          sc->sc_reqlen = xlen;   /* XXX: or less? */
  
  #ifdef  SUNSCPAL_DEBUG
          if (sunscpal_debug & SUNSCPAL_DBG_DMA) {
                  printf("%s: dh=%p, pa=0x%lx, xlen=0x%x\n",
                      __func__, dh, data_pa, xlen);
          }
  #endif
  
          /* sync the DMA map: */
          bus_dmamap_sync(sc->sunscpal_dmat, dh->dh_dmamap, 0, dh->dh_maplen,
              ((xs->xs_control & XS_CTL_DATA_OUT) == 0 ?
              BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE));
  
          /* Load the start address and the count. */
          SUNSCPAL_WRITE_2(sc, sunscpal_dma_addr_h, (data_pa >> 16) & 0xFFFF);
          SUNSCPAL_WRITE_2(sc, sunscpal_dma_addr_l, (data_pa >> 0) & 0xFFFF);
          SUNSCPAL_WRITE_2(sc, sunscpal_dma_count, SUNSCPAL_DMA_COUNT_FLIP(xlen));
  }
  
  #endif /* SUNSCPAL_USE_BUS_DMA */

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