The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/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/amd64/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 <amd64/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 #define ISARAM_END      0x1000000
   81 
   82 static int isa_dmarangecheck(caddr_t va, u_int length, int chan);
   83 
   84 static caddr_t  dma_bouncebuf[8];
   85 static u_int    dma_bouncebufsize[8];
   86 static u_int8_t dma_bounced = 0;
   87 static u_int8_t dma_busy = 0;           /* Used in isa_dmastart() */
   88 static u_int8_t dma_inuse = 0;          /* User for acquire/release */
   89 static u_int8_t dma_auto_mode = 0;
   90 
   91 #define VALID_DMA_MASK (7)
   92 
   93 /* high byte of address is stored in this port for i-th dma channel */
   94 static int dmapageport[8] = { 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
   95 
   96 /*
   97  * Setup a DMA channel's bounce buffer.
   98  */
   99 void
  100 isa_dmainit(chan, bouncebufsize)
  101         int chan;
  102         u_int bouncebufsize;
  103 {
  104         void *buf;
  105 
  106         /*
  107          * If a DMA channel is shared, both drivers have to call isa_dmainit
  108          * since they don't know that the other driver will do it.
  109          * Just return if we're already set up good.
  110          * XXX: this only works if they agree on the bouncebuf size.  This
  111          * XXX: is typically the case since they are multiple instances of
  112          * XXX: the same driver.
  113          */
  114         if (dma_bouncebuf[chan] != NULL)
  115                 return;
  116 
  117 #ifdef DIAGNOSTIC
  118         if (chan & ~VALID_DMA_MASK)
  119                 panic("isa_dmainit: channel out of range");
  120 #endif
  121 
  122         dma_bouncebufsize[chan] = bouncebufsize;
  123 
  124         /* Try malloc() first.  It works better if it works. */
  125         buf = malloc(bouncebufsize, M_DEVBUF, M_NOWAIT);
  126         if (buf != NULL) {
  127                 if (isa_dmarangecheck(buf, bouncebufsize, chan) == 0) {
  128                         dma_bouncebuf[chan] = buf;
  129                         return;
  130                 }
  131                 free(buf, M_DEVBUF);
  132         }
  133         buf = contigmalloc(bouncebufsize, M_DEVBUF, M_NOWAIT, 0ul, 0xfffffful,
  134                            1ul, chan & 4 ? 0x20000ul : 0x10000ul);
  135         if (buf == NULL)
  136                 printf("isa_dmainit(%d, %d) failed\n", chan, bouncebufsize);
  137         else
  138                 dma_bouncebuf[chan] = buf;
  139 }
  140 
  141 /*
  142  * Register a DMA channel's usage.  Usually called from a device driver
  143  * in open() or during its initialization.
  144  */
  145 int
  146 isa_dma_acquire(chan)
  147         int chan;
  148 {
  149 #ifdef DIAGNOSTIC
  150         if (chan & ~VALID_DMA_MASK)
  151                 panic("isa_dma_acquire: channel out of range");
  152 #endif
  153 
  154         if (dma_inuse & (1 << chan)) {
  155                 printf("isa_dma_acquire: channel %d already in use\n", chan);
  156                 return (EBUSY);
  157         }
  158         dma_inuse |= (1 << chan);
  159         dma_auto_mode &= ~(1 << chan);
  160 
  161         return (0);
  162 }
  163 
  164 /*
  165  * Unregister a DMA channel's usage.  Usually called from a device driver
  166  * during close() or during its shutdown.
  167  */
  168 void
  169 isa_dma_release(chan)
  170         int chan;
  171 {
  172 #ifdef DIAGNOSTIC
  173         if (chan & ~VALID_DMA_MASK)
  174                 panic("isa_dma_release: channel out of range");
  175 
  176         if ((dma_inuse & (1 << chan)) == 0)
  177                 printf("isa_dma_release: channel %d not in use\n", chan);
  178 #endif
  179 
  180         if (dma_busy & (1 << chan)) {
  181                 dma_busy &= ~(1 << chan);
  182                 /* 
  183                  * XXX We should also do "dma_bounced &= (1 << chan);"
  184                  * because we are acting on behalf of isa_dmadone() which
  185                  * was not called to end the last DMA operation.  This does
  186                  * not matter now, but it may in the future.
  187                  */
  188         }
  189 
  190         dma_inuse &= ~(1 << chan);
  191         dma_auto_mode &= ~(1 << chan);
  192 }
  193 
  194 /*
  195  * isa_dmacascade(): program 8237 DMA controller channel to accept
  196  * external dma control by a board.
  197  */
  198 void
  199 isa_dmacascade(chan)
  200         int chan;
  201 {
  202 #ifdef DIAGNOSTIC
  203         if (chan & ~VALID_DMA_MASK)
  204                 panic("isa_dmacascade: channel out of range");
  205 #endif
  206 
  207         /* set dma channel mode, and set dma channel mode */
  208         if ((chan & 4) == 0) {
  209                 outb(DMA1_MODE, DMA37MD_CASCADE | chan);
  210                 outb(DMA1_SMSK, chan);
  211         } else {
  212                 outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
  213                 outb(DMA2_SMSK, chan & 3);
  214         }
  215 }
  216 
  217 /*
  218  * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
  219  * problems by using a bounce buffer.
  220  */
  221 void
  222 isa_dmastart(int flags, caddr_t addr, u_int nbytes, int chan)
  223 {
  224         vm_paddr_t phys;
  225         int waport;
  226         caddr_t newaddr;
  227 
  228         GIANT_REQUIRED;
  229 
  230 #ifdef DIAGNOSTIC
  231         if (chan & ~VALID_DMA_MASK)
  232                 panic("isa_dmastart: channel out of range");
  233 
  234         if ((chan < 4 && nbytes > (1<<16))
  235             || (chan >= 4 && (nbytes > (1<<17) || (uintptr_t)addr & 1)))
  236                 panic("isa_dmastart: impossible request");
  237 
  238         if ((dma_inuse & (1 << chan)) == 0)
  239                 printf("isa_dmastart: channel %d not acquired\n", chan);
  240 #endif
  241 
  242 #if 0
  243         /*
  244          * XXX This should be checked, but drivers like ad1848 only call
  245          * isa_dmastart() once because they use Auto DMA mode.  If we
  246          * leave this in, drivers that do this will print this continuously.
  247          */
  248         if (dma_busy & (1 << chan))
  249                 printf("isa_dmastart: channel %d busy\n", chan);
  250 #endif
  251 
  252         dma_busy |= (1 << chan);
  253 
  254         if (isa_dmarangecheck(addr, nbytes, chan)) {
  255                 if (dma_bouncebuf[chan] == NULL
  256                     || dma_bouncebufsize[chan] < nbytes)
  257                         panic("isa_dmastart: bad bounce buffer"); 
  258                 dma_bounced |= (1 << chan);
  259                 newaddr = dma_bouncebuf[chan];
  260 
  261                 /* copy bounce buffer on write */
  262                 if (!(flags & ISADMA_READ))
  263                         bcopy(addr, newaddr, nbytes);
  264                 addr = newaddr;
  265         }
  266 
  267         /* translate to physical */
  268         phys = pmap_extract(kernel_pmap, (vm_offset_t)addr);
  269 
  270         if (flags & ISADMA_RAW) {
  271             dma_auto_mode |= (1 << chan);
  272         } else { 
  273             dma_auto_mode &= ~(1 << chan);
  274         }
  275 
  276         if ((chan & 4) == 0) {
  277                 /*
  278                  * Program one of DMA channels 0..3.  These are
  279                  * byte mode channels.
  280                  */
  281                 /* set dma channel mode, and reset address ff */
  282 
  283                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  284                 if (flags & ISADMA_RAW) {
  285                   if (flags & ISADMA_READ)
  286                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_WRITE|chan);
  287                   else
  288                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_READ|chan);
  289                 }
  290                 else
  291                 if (flags & ISADMA_READ)
  292                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
  293                 else
  294                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
  295                 outb(DMA1_FFC, 0);
  296 
  297                 /* send start address */
  298                 waport =  DMA1_CHN(chan);
  299                 outb(waport, phys);
  300                 outb(waport, phys>>8);
  301                 outb(dmapageport[chan], phys>>16);
  302 
  303                 /* send count */
  304                 outb(waport + 1, --nbytes);
  305                 outb(waport + 1, nbytes>>8);
  306 
  307                 /* unmask channel */
  308                 outb(DMA1_SMSK, chan);
  309         } else {
  310                 /*
  311                  * Program one of DMA channels 4..7.  These are
  312                  * word mode channels.
  313                  */
  314                 /* set dma channel mode, and reset address ff */
  315 
  316                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  317                 if (flags & ISADMA_RAW) {
  318                   if (flags & ISADMA_READ)
  319                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_WRITE|(chan&3));
  320                   else
  321                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_READ|(chan&3));
  322                 }
  323                 else
  324                 if (flags & ISADMA_READ)
  325                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
  326                 else
  327                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
  328                 outb(DMA2_FFC, 0);
  329 
  330                 /* send start address */
  331                 waport = DMA2_CHN(chan - 4);
  332                 outb(waport, phys>>1);
  333                 outb(waport, phys>>9);
  334                 outb(dmapageport[chan], phys>>16);
  335 
  336                 /* send count */
  337                 nbytes >>= 1;
  338                 outb(waport + 2, --nbytes);
  339                 outb(waport + 2, nbytes>>8);
  340 
  341                 /* unmask channel */
  342                 outb(DMA2_SMSK, chan & 3);
  343         }
  344 }
  345 
  346 void
  347 isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
  348 {  
  349 #ifdef DIAGNOSTIC
  350         if (chan & ~VALID_DMA_MASK)
  351                 panic("isa_dmadone: channel out of range");
  352 
  353         if ((dma_inuse & (1 << chan)) == 0)
  354                 printf("isa_dmadone: channel %d not acquired\n", chan);
  355 #endif
  356 
  357         if (((dma_busy & (1 << chan)) == 0) && 
  358             (dma_auto_mode & (1 << chan)) == 0 )
  359                 printf("isa_dmadone: channel %d not busy\n", chan);
  360 
  361         if ((dma_auto_mode & (1 << chan)) == 0)
  362                 outb(chan & 4 ? DMA2_SMSK : DMA1_SMSK, (chan & 3) | 4);
  363 
  364         if (dma_bounced & (1 << chan)) {
  365                 /* copy bounce buffer on read */
  366                 if (flags & ISADMA_READ)
  367                         bcopy(dma_bouncebuf[chan], addr, nbytes);
  368 
  369                 dma_bounced &= ~(1 << chan);
  370         }
  371         dma_busy &= ~(1 << chan);
  372 }
  373 
  374 /*
  375  * Check for problems with the address range of a DMA transfer
  376  * (non-contiguous physical pages, outside of bus address space,
  377  * crossing DMA page boundaries).
  378  * Return true if special handling needed.
  379  */
  380 
  381 static int
  382 isa_dmarangecheck(caddr_t va, u_int length, int chan)
  383 {
  384         vm_paddr_t phys, priorpage = 0;
  385         vm_offset_t endva;
  386         u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
  387 
  388         GIANT_REQUIRED;
  389 
  390         endva = (vm_offset_t)round_page((vm_offset_t)va + length);
  391         for (; va < (caddr_t) endva ; va += PAGE_SIZE) {
  392                 phys = trunc_page(pmap_extract(kernel_pmap, (vm_offset_t)va));
  393                 if (phys == 0)
  394                         panic("isa_dmacheck: no physical page present");
  395                 if (phys >= ISARAM_END)
  396                         return (1);
  397                 if (priorpage) {
  398                         if (priorpage + PAGE_SIZE != phys)
  399                                 return (1);
  400                         /* check if crossing a DMA page boundary */
  401                         if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
  402                                 return (1);
  403                 }
  404                 priorpage = phys;
  405         }
  406         return (0);
  407 }
  408 
  409 /*
  410  * Query the progress of a transfer on a DMA channel.
  411  *
  412  * To avoid having to interrupt a transfer in progress, we sample
  413  * each of the high and low databytes twice, and apply the following
  414  * logic to determine the correct count.
  415  *
  416  * Reads are performed with interrupts disabled, thus it is to be
  417  * expected that the time between reads is very small.  At most
  418  * one rollover in the low count byte can be expected within the
  419  * four reads that are performed.
  420  *
  421  * There are three gaps in which a rollover can occur :
  422  *
  423  * - read low1
  424  *              gap1
  425  * - read high1
  426  *              gap2
  427  * - read low2
  428  *              gap3
  429  * - read high2
  430  *
  431  * If a rollover occurs in gap1 or gap2, the low2 value will be
  432  * greater than the low1 value.  In this case, low2 and high2 are a
  433  * corresponding pair. 
  434  *
  435  * In any other case, low1 and high1 can be considered to be correct.
  436  *
  437  * The function returns the number of bytes remaining in the transfer,
  438  * or -1 if the channel requested is not active.
  439  *
  440  */
  441 int
  442 isa_dmastatus(int chan)
  443 {
  444         u_long  cnt = 0;
  445         int     ffport, waport;
  446         u_long  low1, high1, low2, high2;
  447 
  448         /* channel active? */
  449         if ((dma_inuse & (1 << chan)) == 0) {
  450                 printf("isa_dmastatus: channel %d not active\n", chan);
  451                 return(-1);
  452         }
  453         /* channel busy? */
  454 
  455         if (((dma_busy & (1 << chan)) == 0) &&
  456             (dma_auto_mode & (1 << chan)) == 0 ) {
  457             printf("chan %d not busy\n", chan);
  458             return -2 ;
  459         }       
  460         if (chan < 4) {                 /* low DMA controller */
  461                 ffport = DMA1_FFC;
  462                 waport = DMA1_CHN(chan) + 1;
  463         } else {                        /* high DMA controller */
  464                 ffport = DMA2_FFC;
  465                 waport = DMA2_CHN(chan - 4) + 2;
  466         }
  467 
  468         disable_intr();                 /* no interrupts Mr Jones! */
  469         outb(ffport, 0);                /* clear register LSB flipflop */
  470         low1 = inb(waport);
  471         high1 = inb(waport);
  472         outb(ffport, 0);                /* clear again */
  473         low2 = inb(waport);
  474         high2 = inb(waport);
  475         enable_intr();                  /* enable interrupts again */
  476 
  477         /* 
  478          * Now decide if a wrap has tried to skew our results.
  479          * Note that after TC, the count will read 0xffff, while we want 
  480          * to return zero, so we add and then mask to compensate.
  481          */
  482         if (low1 >= low2) {
  483                 cnt = (low1 + (high1 << 8) + 1) & 0xffff;
  484         } else {
  485                 cnt = (low2 + (high2 << 8) + 1) & 0xffff;
  486         }
  487 
  488         if (chan >= 4)                  /* high channels move words */
  489                 cnt *= 2;
  490         return(cnt);
  491 }
  492 
  493 /*
  494  * Reached terminal count yet ?
  495  */
  496 int
  497 isa_dmatc(int chan)
  498 {
  499 
  500         if (chan < 4)
  501                 return(inb(DMA1_STATUS) & (1 << chan));
  502         else
  503                 return(inb(DMA2_STATUS) & (1 << (chan & 3)));
  504 }
  505 
  506 /*
  507  * Stop a DMA transfer currently in progress.
  508  */
  509 int
  510 isa_dmastop(int chan) 
  511 {
  512         if ((dma_inuse & (1 << chan)) == 0)
  513                 printf("isa_dmastop: channel %d not acquired\n", chan);  
  514 
  515         if (((dma_busy & (1 << chan)) == 0) &&
  516             ((dma_auto_mode & (1 << chan)) == 0)) {
  517                 printf("chan %d not busy\n", chan);
  518                 return -2 ;
  519         }
  520     
  521         if ((chan & 4) == 0) {
  522                 outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
  523         } else {
  524                 outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
  525         }
  526         return(isa_dmastatus(chan));
  527 }
  528 
  529 /*
  530  * Attach to the ISA PnP descriptor for the AT DMA controller
  531  */
  532 static struct isa_pnp_id atdma_ids[] = {
  533         { 0x0002d041 /* PNP0200 */, "AT DMA controller" },
  534         { 0 }
  535 };
  536 
  537 static int
  538 atdma_probe(device_t dev)
  539 {
  540         int result;
  541         
  542         if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, atdma_ids)) <= 0)
  543                 device_quiet(dev);
  544         return(result);
  545 }
  546 
  547 static int
  548 atdma_attach(device_t dev)
  549 {
  550         return(0);
  551 }
  552 
  553 static device_method_t atdma_methods[] = {
  554         /* Device interface */
  555         DEVMETHOD(device_probe,         atdma_probe),
  556         DEVMETHOD(device_attach,        atdma_attach),
  557         DEVMETHOD(device_detach,        bus_generic_detach),
  558         DEVMETHOD(device_shutdown,      bus_generic_shutdown),
  559         DEVMETHOD(device_suspend,       bus_generic_suspend),
  560         DEVMETHOD(device_resume,        bus_generic_resume),
  561         { 0, 0 }
  562 };
  563 
  564 static driver_t atdma_driver = {
  565         "atdma",
  566         atdma_methods,
  567         1,              /* no softc */
  568 };
  569 
  570 static devclass_t atdma_devclass;
  571 
  572 DRIVER_MODULE(atdma, isa, atdma_driver, atdma_devclass, 0, 0);
  573 DRIVER_MODULE(atdma, acpi, atdma_driver, atdma_devclass, 0, 0);

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