The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/isa/isa_dma.c

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    1 /*-
    2  * Copyright (c) 1991 The Regents of the University of California.
    3  * All rights reserved.
    4  *
    5  * This code is derived from software contributed to Berkeley by
    6  * William Jolitz.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 4. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      from: @(#)isa.c 7.2 (Berkeley) 5/13/91
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/5.4/sys/i386/isa/isa_dma.c 143242 2005-03-07 13:10:48Z phk $");
   37 
   38 /*
   39  * code to manage AT bus
   40  *
   41  * 92/08/18  Frank P. MacLachlan (fpm@crash.cts.com):
   42  * Fixed uninitialized variable problem and added code to deal
   43  * with DMA page boundaries in isa_dmarangecheck().  Fixed word
   44  * mode DMA count compution and reorganized DMA setup code in
   45  * isa_dmastart()
   46  */
   47 
   48 #include <sys/param.h>
   49 #include <sys/systm.h>
   50 #include <sys/bus.h>
   51 #include <sys/kernel.h>
   52 #include <sys/malloc.h>
   53 #include <sys/lock.h>
   54 #include <sys/proc.h>
   55 #include <sys/mutex.h>
   56 #include <sys/module.h>
   57 #include <vm/vm.h>
   58 #include <vm/vm_param.h>
   59 #include <vm/pmap.h>
   60 #include <i386/isa/isa.h>
   61 #include <dev/ic/i8237.h>
   62 #include <isa/isavar.h>
   63 
   64 /*
   65 **  Register definitions for DMA controller 1 (channels 0..3):
   66 */
   67 #define DMA1_CHN(c)     (IO_DMA1 + 1*(2*(c)))   /* addr reg for channel c */
   68 #define DMA1_SMSK       (IO_DMA1 + 1*10)        /* single mask register */
   69 #define DMA1_MODE       (IO_DMA1 + 1*11)        /* mode register */
   70 #define DMA1_FFC        (IO_DMA1 + 1*12)        /* clear first/last FF */
   71 
   72 /*
   73 **  Register definitions for DMA controller 2 (channels 4..7):
   74 */
   75 #define DMA2_CHN(c)     (IO_DMA2 + 2*(2*(c)))   /* addr reg for channel c */
   76 #define DMA2_SMSK       (IO_DMA2 + 2*10)        /* single mask register */
   77 #define DMA2_MODE       (IO_DMA2 + 2*11)        /* mode register */
   78 #define DMA2_FFC        (IO_DMA2 + 2*12)        /* clear first/last FF */
   79 
   80 static int isa_dmarangecheck(caddr_t va, u_int length, int chan);
   81 
   82 static caddr_t  dma_bouncebuf[8];
   83 static u_int    dma_bouncebufsize[8];
   84 static u_int8_t dma_bounced = 0;
   85 static u_int8_t dma_busy = 0;           /* Used in isa_dmastart() */
   86 static u_int8_t dma_inuse = 0;          /* User for acquire/release */
   87 static u_int8_t dma_auto_mode = 0;
   88 
   89 #define VALID_DMA_MASK (7)
   90 
   91 /* high byte of address is stored in this port for i-th dma channel */
   92 static int dmapageport[8] = { 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
   93 
   94 /*
   95  * Setup a DMA channel's bounce buffer.
   96  */
   97 void
   98 isa_dmainit(chan, bouncebufsize)
   99         int chan;
  100         u_int bouncebufsize;
  101 {
  102         void *buf;
  103 
  104         /*
  105          * If a DMA channel is shared, both drivers have to call isa_dmainit
  106          * since they don't know that the other driver will do it.
  107          * Just return if we're already set up good.
  108          * XXX: this only works if they agree on the bouncebuf size.  This
  109          * XXX: is typically the case since they are multiple instances of
  110          * XXX: the same driver.
  111          */
  112         if (dma_bouncebuf[chan] != NULL)
  113                 return;
  114 
  115 #ifdef DIAGNOSTIC
  116         if (chan & ~VALID_DMA_MASK)
  117                 panic("isa_dmainit: channel out of range");
  118 #endif
  119 
  120         dma_bouncebufsize[chan] = bouncebufsize;
  121 
  122         /* Try malloc() first.  It works better if it works. */
  123         buf = malloc(bouncebufsize, M_DEVBUF, M_NOWAIT);
  124         if (buf != NULL) {
  125                 if (isa_dmarangecheck(buf, bouncebufsize, chan) == 0) {
  126                         dma_bouncebuf[chan] = buf;
  127                         return;
  128                 }
  129                 free(buf, M_DEVBUF);
  130         }
  131         buf = contigmalloc(bouncebufsize, M_DEVBUF, M_NOWAIT, 0ul, 0xfffffful,
  132                            1ul, chan & 4 ? 0x20000ul : 0x10000ul);
  133         if (buf == NULL)
  134                 printf("isa_dmainit(%d, %d) failed\n", chan, bouncebufsize);
  135         else
  136                 dma_bouncebuf[chan] = buf;
  137 }
  138 
  139 /*
  140  * Register a DMA channel's usage.  Usually called from a device driver
  141  * in open() or during its initialization.
  142  */
  143 int
  144 isa_dma_acquire(chan)
  145         int chan;
  146 {
  147 #ifdef DIAGNOSTIC
  148         if (chan & ~VALID_DMA_MASK)
  149                 panic("isa_dma_acquire: channel out of range");
  150 #endif
  151 
  152         if (dma_inuse & (1 << chan)) {
  153                 printf("isa_dma_acquire: channel %d already in use\n", chan);
  154                 return (EBUSY);
  155         }
  156         dma_inuse |= (1 << chan);
  157         dma_auto_mode &= ~(1 << chan);
  158 
  159         return (0);
  160 }
  161 
  162 /*
  163  * Unregister a DMA channel's usage.  Usually called from a device driver
  164  * during close() or during its shutdown.
  165  */
  166 void
  167 isa_dma_release(chan)
  168         int chan;
  169 {
  170 #ifdef DIAGNOSTIC
  171         if (chan & ~VALID_DMA_MASK)
  172                 panic("isa_dma_release: channel out of range");
  173 
  174         if ((dma_inuse & (1 << chan)) == 0)
  175                 printf("isa_dma_release: channel %d not in use\n", chan);
  176 #endif
  177 
  178         if (dma_busy & (1 << chan)) {
  179                 dma_busy &= ~(1 << chan);
  180                 /* 
  181                  * XXX We should also do "dma_bounced &= (1 << chan);"
  182                  * because we are acting on behalf of isa_dmadone() which
  183                  * was not called to end the last DMA operation.  This does
  184                  * not matter now, but it may in the future.
  185                  */
  186         }
  187 
  188         dma_inuse &= ~(1 << chan);
  189         dma_auto_mode &= ~(1 << chan);
  190 }
  191 
  192 /*
  193  * isa_dmacascade(): program 8237 DMA controller channel to accept
  194  * external dma control by a board.
  195  */
  196 void
  197 isa_dmacascade(chan)
  198         int chan;
  199 {
  200 #ifdef DIAGNOSTIC
  201         if (chan & ~VALID_DMA_MASK)
  202                 panic("isa_dmacascade: channel out of range");
  203 #endif
  204 
  205         /* set dma channel mode, and set dma channel mode */
  206         if ((chan & 4) == 0) {
  207                 outb(DMA1_MODE, DMA37MD_CASCADE | chan);
  208                 outb(DMA1_SMSK, chan);
  209         } else {
  210                 outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
  211                 outb(DMA2_SMSK, chan & 3);
  212         }
  213 }
  214 
  215 /*
  216  * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
  217  * problems by using a bounce buffer.
  218  */
  219 void
  220 isa_dmastart(int flags, caddr_t addr, u_int nbytes, int chan)
  221 {
  222         vm_paddr_t phys;
  223         int waport;
  224         caddr_t newaddr;
  225 
  226         GIANT_REQUIRED;
  227 
  228 #ifdef DIAGNOSTIC
  229         if (chan & ~VALID_DMA_MASK)
  230                 panic("isa_dmastart: channel out of range");
  231 
  232         if ((chan < 4 && nbytes > (1<<16))
  233             || (chan >= 4 && (nbytes > (1<<17) || (u_int)addr & 1)))
  234                 panic("isa_dmastart: impossible request");
  235 
  236         if ((dma_inuse & (1 << chan)) == 0)
  237                 printf("isa_dmastart: channel %d not acquired\n", chan);
  238 #endif
  239 
  240 #if 0
  241         /*
  242          * XXX This should be checked, but drivers like ad1848 only call
  243          * isa_dmastart() once because they use Auto DMA mode.  If we
  244          * leave this in, drivers that do this will print this continuously.
  245          */
  246         if (dma_busy & (1 << chan))
  247                 printf("isa_dmastart: channel %d busy\n", chan);
  248 #endif
  249 
  250         dma_busy |= (1 << chan);
  251 
  252         if (isa_dmarangecheck(addr, nbytes, chan)) {
  253                 if (dma_bouncebuf[chan] == NULL
  254                     || dma_bouncebufsize[chan] < nbytes)
  255                         panic("isa_dmastart: bad bounce buffer"); 
  256                 dma_bounced |= (1 << chan);
  257                 newaddr = dma_bouncebuf[chan];
  258 
  259                 /* copy bounce buffer on write */
  260                 if (!(flags & ISADMA_READ))
  261                         bcopy(addr, newaddr, nbytes);
  262                 addr = newaddr;
  263         }
  264 
  265         /* translate to physical */
  266         phys = pmap_extract(kernel_pmap, (vm_offset_t)addr);
  267 
  268         if (flags & ISADMA_RAW) {
  269             dma_auto_mode |= (1 << chan);
  270         } else { 
  271             dma_auto_mode &= ~(1 << chan);
  272         }
  273 
  274         if ((chan & 4) == 0) {
  275                 /*
  276                  * Program one of DMA channels 0..3.  These are
  277                  * byte mode channels.
  278                  */
  279                 /* set dma channel mode, and reset address ff */
  280 
  281                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  282                 if (flags & ISADMA_RAW) {
  283                   if (flags & ISADMA_READ)
  284                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_WRITE|chan);
  285                   else
  286                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_READ|chan);
  287                 }
  288                 else
  289                 if (flags & ISADMA_READ)
  290                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
  291                 else
  292                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
  293                 outb(DMA1_FFC, 0);
  294 
  295                 /* send start address */
  296                 waport =  DMA1_CHN(chan);
  297                 outb(waport, phys);
  298                 outb(waport, phys>>8);
  299                 outb(dmapageport[chan], phys>>16);
  300 
  301                 /* send count */
  302                 outb(waport + 1, --nbytes);
  303                 outb(waport + 1, nbytes>>8);
  304 
  305                 /* unmask channel */
  306                 outb(DMA1_SMSK, chan);
  307         } else {
  308                 /*
  309                  * Program one of DMA channels 4..7.  These are
  310                  * word mode channels.
  311                  */
  312                 /* set dma channel mode, and reset address ff */
  313 
  314                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  315                 if (flags & ISADMA_RAW) {
  316                   if (flags & ISADMA_READ)
  317                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_WRITE|(chan&3));
  318                   else
  319                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_READ|(chan&3));
  320                 }
  321                 else
  322                 if (flags & ISADMA_READ)
  323                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
  324                 else
  325                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
  326                 outb(DMA2_FFC, 0);
  327 
  328                 /* send start address */
  329                 waport = DMA2_CHN(chan - 4);
  330                 outb(waport, phys>>1);
  331                 outb(waport, phys>>9);
  332                 outb(dmapageport[chan], phys>>16);
  333 
  334                 /* send count */
  335                 nbytes >>= 1;
  336                 outb(waport + 2, --nbytes);
  337                 outb(waport + 2, nbytes>>8);
  338 
  339                 /* unmask channel */
  340                 outb(DMA2_SMSK, chan & 3);
  341         }
  342 }
  343 
  344 void
  345 isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
  346 {  
  347 #ifdef DIAGNOSTIC
  348         if (chan & ~VALID_DMA_MASK)
  349                 panic("isa_dmadone: channel out of range");
  350 
  351         if ((dma_inuse & (1 << chan)) == 0)
  352                 printf("isa_dmadone: channel %d not acquired\n", chan);
  353 #endif
  354 
  355         if (((dma_busy & (1 << chan)) == 0) && 
  356             (dma_auto_mode & (1 << chan)) == 0 )
  357                 printf("isa_dmadone: channel %d not busy\n", chan);
  358 
  359         if ((dma_auto_mode & (1 << chan)) == 0)
  360                 outb(chan & 4 ? DMA2_SMSK : DMA1_SMSK, (chan & 3) | 4);
  361 
  362         if (dma_bounced & (1 << chan)) {
  363                 /* copy bounce buffer on read */
  364                 if (flags & ISADMA_READ)
  365                         bcopy(dma_bouncebuf[chan], addr, nbytes);
  366 
  367                 dma_bounced &= ~(1 << chan);
  368         }
  369         dma_busy &= ~(1 << chan);
  370 }
  371 
  372 /*
  373  * Check for problems with the address range of a DMA transfer
  374  * (non-contiguous physical pages, outside of bus address space,
  375  * crossing DMA page boundaries).
  376  * Return true if special handling needed.
  377  */
  378 
  379 static int
  380 isa_dmarangecheck(caddr_t va, u_int length, int chan)
  381 {
  382         vm_paddr_t phys, priorpage = 0;
  383         vm_offset_t endva;
  384         u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
  385 
  386         GIANT_REQUIRED;
  387 
  388         endva = (vm_offset_t)round_page((vm_offset_t)va + length);
  389         for (; va < (caddr_t) endva ; va += PAGE_SIZE) {
  390                 phys = trunc_page(pmap_extract(kernel_pmap, (vm_offset_t)va));
  391 #define ISARAM_END      RAM_END
  392                 if (phys == 0)
  393                         panic("isa_dmacheck: no physical page present");
  394                 if (phys >= ISARAM_END)
  395                         return (1);
  396                 if (priorpage) {
  397                         if (priorpage + PAGE_SIZE != phys)
  398                                 return (1);
  399                         /* check if crossing a DMA page boundary */
  400                         if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
  401                                 return (1);
  402                 }
  403                 priorpage = phys;
  404         }
  405         return (0);
  406 }
  407 
  408 /*
  409  * Query the progress of a transfer on a DMA channel.
  410  *
  411  * To avoid having to interrupt a transfer in progress, we sample
  412  * each of the high and low databytes twice, and apply the following
  413  * logic to determine the correct count.
  414  *
  415  * Reads are performed with interrupts disabled, thus it is to be
  416  * expected that the time between reads is very small.  At most
  417  * one rollover in the low count byte can be expected within the
  418  * four reads that are performed.
  419  *
  420  * There are three gaps in which a rollover can occur :
  421  *
  422  * - read low1
  423  *              gap1
  424  * - read high1
  425  *              gap2
  426  * - read low2
  427  *              gap3
  428  * - read high2
  429  *
  430  * If a rollover occurs in gap1 or gap2, the low2 value will be
  431  * greater than the low1 value.  In this case, low2 and high2 are a
  432  * corresponding pair. 
  433  *
  434  * In any other case, low1 and high1 can be considered to be correct.
  435  *
  436  * The function returns the number of bytes remaining in the transfer,
  437  * or -1 if the channel requested is not active.
  438  *
  439  */
  440 int
  441 isa_dmastatus(int chan)
  442 {
  443         u_long  cnt = 0;
  444         int     ffport, waport;
  445         u_long  low1, high1, low2, high2;
  446 
  447         /* channel active? */
  448         if ((dma_inuse & (1 << chan)) == 0) {
  449                 printf("isa_dmastatus: channel %d not active\n", chan);
  450                 return(-1);
  451         }
  452         /* channel busy? */
  453 
  454         if (((dma_busy & (1 << chan)) == 0) &&
  455             (dma_auto_mode & (1 << chan)) == 0 ) {
  456             printf("chan %d not busy\n", chan);
  457             return -2 ;
  458         }       
  459         if (chan < 4) {                 /* low DMA controller */
  460                 ffport = DMA1_FFC;
  461                 waport = DMA1_CHN(chan) + 1;
  462         } else {                        /* high DMA controller */
  463                 ffport = DMA2_FFC;
  464                 waport = DMA2_CHN(chan - 4) + 2;
  465         }
  466 
  467         disable_intr();                 /* no interrupts Mr Jones! */
  468         outb(ffport, 0);                /* clear register LSB flipflop */
  469         low1 = inb(waport);
  470         high1 = inb(waport);
  471         outb(ffport, 0);                /* clear again */
  472         low2 = inb(waport);
  473         high2 = inb(waport);
  474         enable_intr();                  /* enable interrupts again */
  475 
  476         /* 
  477          * Now decide if a wrap has tried to skew our results.
  478          * Note that after TC, the count will read 0xffff, while we want 
  479          * to return zero, so we add and then mask to compensate.
  480          */
  481         if (low1 >= low2) {
  482                 cnt = (low1 + (high1 << 8) + 1) & 0xffff;
  483         } else {
  484                 cnt = (low2 + (high2 << 8) + 1) & 0xffff;
  485         }
  486 
  487         if (chan >= 4)                  /* high channels move words */
  488                 cnt *= 2;
  489         return(cnt);
  490 }
  491 
  492 /*
  493  * Reached terminal count yet ?
  494  */
  495 int
  496 isa_dmatc(int chan)
  497 {
  498 
  499         if (chan < 4)
  500                 return(inb(DMA1_STATUS) & (1 << chan));
  501         else
  502                 return(inb(DMA2_STATUS) & (1 << (chan & 3)));
  503 }
  504 
  505 /*
  506  * Stop a DMA transfer currently in progress.
  507  */
  508 int
  509 isa_dmastop(int chan) 
  510 {
  511         if ((dma_inuse & (1 << chan)) == 0)
  512                 printf("isa_dmastop: channel %d not acquired\n", chan);  
  513 
  514         if (((dma_busy & (1 << chan)) == 0) &&
  515             ((dma_auto_mode & (1 << chan)) == 0)) {
  516                 printf("chan %d not busy\n", chan);
  517                 return -2 ;
  518         }
  519     
  520         if ((chan & 4) == 0) {
  521                 outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
  522         } else {
  523                 outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
  524         }
  525         return(isa_dmastatus(chan));
  526 }
  527 
  528 /*
  529  * Attach to the ISA PnP descriptor for the AT DMA controller
  530  */
  531 static struct isa_pnp_id atdma_ids[] = {
  532         { 0x0002d041 /* PNP0200 */, "AT DMA controller" },
  533         { 0 }
  534 };
  535 
  536 static int
  537 atdma_probe(device_t dev)
  538 {
  539         int result;
  540         
  541         if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, atdma_ids)) <= 0)
  542                 device_quiet(dev);
  543         return(result);
  544 }
  545 
  546 static int
  547 atdma_attach(device_t dev)
  548 {
  549         return(0);
  550 }
  551 
  552 static device_method_t atdma_methods[] = {
  553         /* Device interface */
  554         DEVMETHOD(device_probe,         atdma_probe),
  555         DEVMETHOD(device_attach,        atdma_attach),
  556         DEVMETHOD(device_detach,        bus_generic_detach),
  557         DEVMETHOD(device_shutdown,      bus_generic_shutdown),
  558         DEVMETHOD(device_suspend,       bus_generic_suspend),
  559         DEVMETHOD(device_resume,        bus_generic_resume),
  560         { 0, 0 }
  561 };
  562 
  563 static driver_t atdma_driver = {
  564         "atdma",
  565         atdma_methods,
  566         1,              /* no softc */
  567 };
  568 
  569 static devclass_t atdma_devclass;
  570 
  571 DRIVER_MODULE(atdma, isa, atdma_driver, atdma_devclass, 0, 0);
  572 DRIVER_MODULE(atdma, acpi, atdma_driver, atdma_devclass, 0, 0);

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