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/7.4/sys/i386/isa/isa_dma.c 146214 2005-05-14 10:14:56Z nyan $");
   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 <isa/isareg.h>
   61 #include <isa/isavar.h>
   62 #include <isa/isa_dmareg.h>
   63 
   64 static int isa_dmarangecheck(caddr_t va, u_int length, int chan);
   65 
   66 static caddr_t  dma_bouncebuf[8];
   67 static u_int    dma_bouncebufsize[8];
   68 static u_int8_t dma_bounced = 0;
   69 static u_int8_t dma_busy = 0;           /* Used in isa_dmastart() */
   70 static u_int8_t dma_inuse = 0;          /* User for acquire/release */
   71 static u_int8_t dma_auto_mode = 0;
   72 
   73 #define VALID_DMA_MASK (7)
   74 
   75 /* high byte of address is stored in this port for i-th dma channel */
   76 static int dmapageport[8] = { 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
   77 
   78 /*
   79  * Setup a DMA channel's bounce buffer.
   80  */
   81 int
   82 isa_dma_init(int chan, u_int bouncebufsize, int flag)
   83 {
   84         void *buf;
   85 
   86         /*
   87          * If a DMA channel is shared, both drivers have to call isa_dma_init
   88          * since they don't know that the other driver will do it.
   89          * Just return if we're already set up good.
   90          * XXX: this only works if they agree on the bouncebuf size.  This
   91          * XXX: is typically the case since they are multiple instances of
   92          * XXX: the same driver.
   93          */
   94         if (dma_bouncebuf[chan] != NULL)
   95                 return (0);
   96 
   97 #ifdef DIAGNOSTIC
   98         if (chan & ~VALID_DMA_MASK)
   99                 panic("isa_dma_init: channel out of range");
  100 #endif
  101 
  102         dma_bouncebufsize[chan] = bouncebufsize;
  103 
  104         /* Try malloc() first.  It works better if it works. */
  105         buf = malloc(bouncebufsize, M_DEVBUF, flag);
  106         if (buf != NULL) {
  107                 if (isa_dmarangecheck(buf, bouncebufsize, chan) == 0) {
  108                         dma_bouncebuf[chan] = buf;
  109                         return (0);
  110                 }
  111                 free(buf, M_DEVBUF);
  112         }
  113         buf = contigmalloc(bouncebufsize, M_DEVBUF, flag, 0ul, 0xfffffful,
  114                            1ul, chan & 4 ? 0x20000ul : 0x10000ul);
  115         if (buf == NULL)
  116                 return (ENOMEM);
  117         dma_bouncebuf[chan] = buf;
  118         return (0);
  119 }
  120 
  121 /*
  122  * Register a DMA channel's usage.  Usually called from a device driver
  123  * in open() or during its initialization.
  124  */
  125 int
  126 isa_dma_acquire(chan)
  127         int chan;
  128 {
  129 #ifdef DIAGNOSTIC
  130         if (chan & ~VALID_DMA_MASK)
  131                 panic("isa_dma_acquire: channel out of range");
  132 #endif
  133 
  134         if (dma_inuse & (1 << chan)) {
  135                 printf("isa_dma_acquire: channel %d already in use\n", chan);
  136                 return (EBUSY);
  137         }
  138         dma_inuse |= (1 << chan);
  139         dma_auto_mode &= ~(1 << chan);
  140 
  141         return (0);
  142 }
  143 
  144 /*
  145  * Unregister a DMA channel's usage.  Usually called from a device driver
  146  * during close() or during its shutdown.
  147  */
  148 void
  149 isa_dma_release(chan)
  150         int chan;
  151 {
  152 #ifdef DIAGNOSTIC
  153         if (chan & ~VALID_DMA_MASK)
  154                 panic("isa_dma_release: channel out of range");
  155 
  156         if ((dma_inuse & (1 << chan)) == 0)
  157                 printf("isa_dma_release: channel %d not in use\n", chan);
  158 #endif
  159 
  160         if (dma_busy & (1 << chan)) {
  161                 dma_busy &= ~(1 << chan);
  162                 /* 
  163                  * XXX We should also do "dma_bounced &= (1 << chan);"
  164                  * because we are acting on behalf of isa_dmadone() which
  165                  * was not called to end the last DMA operation.  This does
  166                  * not matter now, but it may in the future.
  167                  */
  168         }
  169 
  170         dma_inuse &= ~(1 << chan);
  171         dma_auto_mode &= ~(1 << chan);
  172 }
  173 
  174 /*
  175  * isa_dmacascade(): program 8237 DMA controller channel to accept
  176  * external dma control by a board.
  177  */
  178 void
  179 isa_dmacascade(chan)
  180         int chan;
  181 {
  182 #ifdef DIAGNOSTIC
  183         if (chan & ~VALID_DMA_MASK)
  184                 panic("isa_dmacascade: channel out of range");
  185 #endif
  186 
  187         /* set dma channel mode, and set dma channel mode */
  188         if ((chan & 4) == 0) {
  189                 outb(DMA1_MODE, DMA37MD_CASCADE | chan);
  190                 outb(DMA1_SMSK, chan);
  191         } else {
  192                 outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
  193                 outb(DMA2_SMSK, chan & 3);
  194         }
  195 }
  196 
  197 /*
  198  * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
  199  * problems by using a bounce buffer.
  200  */
  201 void
  202 isa_dmastart(int flags, caddr_t addr, u_int nbytes, int chan)
  203 {
  204         vm_paddr_t phys;
  205         int waport;
  206         caddr_t newaddr;
  207 
  208         GIANT_REQUIRED;
  209 
  210 #ifdef DIAGNOSTIC
  211         if (chan & ~VALID_DMA_MASK)
  212                 panic("isa_dmastart: channel out of range");
  213 
  214         if ((chan < 4 && nbytes > (1<<16))
  215             || (chan >= 4 && (nbytes > (1<<17) || (u_int)addr & 1)))
  216                 panic("isa_dmastart: impossible request");
  217 
  218         if ((dma_inuse & (1 << chan)) == 0)
  219                 printf("isa_dmastart: channel %d not acquired\n", chan);
  220 #endif
  221 
  222 #if 0
  223         /*
  224          * XXX This should be checked, but drivers like ad1848 only call
  225          * isa_dmastart() once because they use Auto DMA mode.  If we
  226          * leave this in, drivers that do this will print this continuously.
  227          */
  228         if (dma_busy & (1 << chan))
  229                 printf("isa_dmastart: channel %d busy\n", chan);
  230 #endif
  231 
  232         dma_busy |= (1 << chan);
  233 
  234         if (isa_dmarangecheck(addr, nbytes, chan)) {
  235                 if (dma_bouncebuf[chan] == NULL
  236                     || dma_bouncebufsize[chan] < nbytes)
  237                         panic("isa_dmastart: bad bounce buffer"); 
  238                 dma_bounced |= (1 << chan);
  239                 newaddr = dma_bouncebuf[chan];
  240 
  241                 /* copy bounce buffer on write */
  242                 if (!(flags & ISADMA_READ))
  243                         bcopy(addr, newaddr, nbytes);
  244                 addr = newaddr;
  245         }
  246 
  247         /* translate to physical */
  248         phys = pmap_extract(kernel_pmap, (vm_offset_t)addr);
  249 
  250         if (flags & ISADMA_RAW) {
  251             dma_auto_mode |= (1 << chan);
  252         } else { 
  253             dma_auto_mode &= ~(1 << chan);
  254         }
  255 
  256         if ((chan & 4) == 0) {
  257                 /*
  258                  * Program one of DMA channels 0..3.  These are
  259                  * byte mode channels.
  260                  */
  261                 /* set dma channel mode, and reset address ff */
  262 
  263                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  264                 if (flags & ISADMA_RAW) {
  265                   if (flags & ISADMA_READ)
  266                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_WRITE|chan);
  267                   else
  268                         outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_READ|chan);
  269                 }
  270                 else
  271                 if (flags & ISADMA_READ)
  272                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
  273                 else
  274                         outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
  275                 outb(DMA1_FFC, 0);
  276 
  277                 /* send start address */
  278                 waport =  DMA1_CHN(chan);
  279                 outb(waport, phys);
  280                 outb(waport, phys>>8);
  281                 outb(dmapageport[chan], phys>>16);
  282 
  283                 /* send count */
  284                 outb(waport + 1, --nbytes);
  285                 outb(waport + 1, nbytes>>8);
  286 
  287                 /* unmask channel */
  288                 outb(DMA1_SMSK, chan);
  289         } else {
  290                 /*
  291                  * Program one of DMA channels 4..7.  These are
  292                  * word mode channels.
  293                  */
  294                 /* set dma channel mode, and reset address ff */
  295 
  296                 /* If ISADMA_RAW flag is set, then use autoinitialise mode */
  297                 if (flags & ISADMA_RAW) {
  298                   if (flags & ISADMA_READ)
  299                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_WRITE|(chan&3));
  300                   else
  301                         outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_READ|(chan&3));
  302                 }
  303                 else
  304                 if (flags & ISADMA_READ)
  305                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
  306                 else
  307                         outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
  308                 outb(DMA2_FFC, 0);
  309 
  310                 /* send start address */
  311                 waport = DMA2_CHN(chan - 4);
  312                 outb(waport, phys>>1);
  313                 outb(waport, phys>>9);
  314                 outb(dmapageport[chan], phys>>16);
  315 
  316                 /* send count */
  317                 nbytes >>= 1;
  318                 outb(waport + 2, --nbytes);
  319                 outb(waport + 2, nbytes>>8);
  320 
  321                 /* unmask channel */
  322                 outb(DMA2_SMSK, chan & 3);
  323         }
  324 }
  325 
  326 void
  327 isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
  328 {  
  329 #ifdef DIAGNOSTIC
  330         if (chan & ~VALID_DMA_MASK)
  331                 panic("isa_dmadone: channel out of range");
  332 
  333         if ((dma_inuse & (1 << chan)) == 0)
  334                 printf("isa_dmadone: channel %d not acquired\n", chan);
  335 #endif
  336 
  337         if (((dma_busy & (1 << chan)) == 0) && 
  338             (dma_auto_mode & (1 << chan)) == 0 )
  339                 printf("isa_dmadone: channel %d not busy\n", chan);
  340 
  341         if ((dma_auto_mode & (1 << chan)) == 0)
  342                 outb(chan & 4 ? DMA2_SMSK : DMA1_SMSK, (chan & 3) | 4);
  343 
  344         if (dma_bounced & (1 << chan)) {
  345                 /* copy bounce buffer on read */
  346                 if (flags & ISADMA_READ)
  347                         bcopy(dma_bouncebuf[chan], addr, nbytes);
  348 
  349                 dma_bounced &= ~(1 << chan);
  350         }
  351         dma_busy &= ~(1 << chan);
  352 }
  353 
  354 /*
  355  * Check for problems with the address range of a DMA transfer
  356  * (non-contiguous physical pages, outside of bus address space,
  357  * crossing DMA page boundaries).
  358  * Return true if special handling needed.
  359  */
  360 
  361 static int
  362 isa_dmarangecheck(caddr_t va, u_int length, int chan)
  363 {
  364         vm_paddr_t phys, priorpage = 0;
  365         vm_offset_t endva;
  366         u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
  367 
  368         GIANT_REQUIRED;
  369 
  370         endva = (vm_offset_t)round_page((vm_offset_t)va + length);
  371         for (; va < (caddr_t) endva ; va += PAGE_SIZE) {
  372                 phys = trunc_page(pmap_extract(kernel_pmap, (vm_offset_t)va));
  373 #define ISARAM_END      RAM_END
  374                 if (phys == 0)
  375                         panic("isa_dmacheck: no physical page present");
  376                 if (phys >= ISARAM_END)
  377                         return (1);
  378                 if (priorpage) {
  379                         if (priorpage + PAGE_SIZE != phys)
  380                                 return (1);
  381                         /* check if crossing a DMA page boundary */
  382                         if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
  383                                 return (1);
  384                 }
  385                 priorpage = phys;
  386         }
  387         return (0);
  388 }
  389 
  390 /*
  391  * Query the progress of a transfer on a DMA channel.
  392  *
  393  * To avoid having to interrupt a transfer in progress, we sample
  394  * each of the high and low databytes twice, and apply the following
  395  * logic to determine the correct count.
  396  *
  397  * Reads are performed with interrupts disabled, thus it is to be
  398  * expected that the time between reads is very small.  At most
  399  * one rollover in the low count byte can be expected within the
  400  * four reads that are performed.
  401  *
  402  * There are three gaps in which a rollover can occur :
  403  *
  404  * - read low1
  405  *              gap1
  406  * - read high1
  407  *              gap2
  408  * - read low2
  409  *              gap3
  410  * - read high2
  411  *
  412  * If a rollover occurs in gap1 or gap2, the low2 value will be
  413  * greater than the low1 value.  In this case, low2 and high2 are a
  414  * corresponding pair. 
  415  *
  416  * In any other case, low1 and high1 can be considered to be correct.
  417  *
  418  * The function returns the number of bytes remaining in the transfer,
  419  * or -1 if the channel requested is not active.
  420  *
  421  */
  422 int
  423 isa_dmastatus(int chan)
  424 {
  425         u_long  cnt = 0;
  426         int     ffport, waport;
  427         u_long  low1, high1, low2, high2;
  428 
  429         /* channel active? */
  430         if ((dma_inuse & (1 << chan)) == 0) {
  431                 printf("isa_dmastatus: channel %d not active\n", chan);
  432                 return(-1);
  433         }
  434         /* channel busy? */
  435 
  436         if (((dma_busy & (1 << chan)) == 0) &&
  437             (dma_auto_mode & (1 << chan)) == 0 ) {
  438             printf("chan %d not busy\n", chan);
  439             return -2 ;
  440         }       
  441         if (chan < 4) {                 /* low DMA controller */
  442                 ffport = DMA1_FFC;
  443                 waport = DMA1_CHN(chan) + 1;
  444         } else {                        /* high DMA controller */
  445                 ffport = DMA2_FFC;
  446                 waport = DMA2_CHN(chan - 4) + 2;
  447         }
  448 
  449         disable_intr();                 /* no interrupts Mr Jones! */
  450         outb(ffport, 0);                /* clear register LSB flipflop */
  451         low1 = inb(waport);
  452         high1 = inb(waport);
  453         outb(ffport, 0);                /* clear again */
  454         low2 = inb(waport);
  455         high2 = inb(waport);
  456         enable_intr();                  /* enable interrupts again */
  457 
  458         /* 
  459          * Now decide if a wrap has tried to skew our results.
  460          * Note that after TC, the count will read 0xffff, while we want 
  461          * to return zero, so we add and then mask to compensate.
  462          */
  463         if (low1 >= low2) {
  464                 cnt = (low1 + (high1 << 8) + 1) & 0xffff;
  465         } else {
  466                 cnt = (low2 + (high2 << 8) + 1) & 0xffff;
  467         }
  468 
  469         if (chan >= 4)                  /* high channels move words */
  470                 cnt *= 2;
  471         return(cnt);
  472 }
  473 
  474 /*
  475  * Reached terminal count yet ?
  476  */
  477 int
  478 isa_dmatc(int chan)
  479 {
  480 
  481         if (chan < 4)
  482                 return(inb(DMA1_STATUS) & (1 << chan));
  483         else
  484                 return(inb(DMA2_STATUS) & (1 << (chan & 3)));
  485 }
  486 
  487 /*
  488  * Stop a DMA transfer currently in progress.
  489  */
  490 int
  491 isa_dmastop(int chan) 
  492 {
  493         if ((dma_inuse & (1 << chan)) == 0)
  494                 printf("isa_dmastop: channel %d not acquired\n", chan);  
  495 
  496         if (((dma_busy & (1 << chan)) == 0) &&
  497             ((dma_auto_mode & (1 << chan)) == 0)) {
  498                 printf("chan %d not busy\n", chan);
  499                 return -2 ;
  500         }
  501     
  502         if ((chan & 4) == 0) {
  503                 outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
  504         } else {
  505                 outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
  506         }
  507         return(isa_dmastatus(chan));
  508 }
  509 
  510 /*
  511  * Attach to the ISA PnP descriptor for the AT DMA controller
  512  */
  513 static struct isa_pnp_id atdma_ids[] = {
  514         { 0x0002d041 /* PNP0200 */, "AT DMA controller" },
  515         { 0 }
  516 };
  517 
  518 static int
  519 atdma_probe(device_t dev)
  520 {
  521         int result;
  522         
  523         if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, atdma_ids)) <= 0)
  524                 device_quiet(dev);
  525         return(result);
  526 }
  527 
  528 static int
  529 atdma_attach(device_t dev)
  530 {
  531         return(0);
  532 }
  533 
  534 static device_method_t atdma_methods[] = {
  535         /* Device interface */
  536         DEVMETHOD(device_probe,         atdma_probe),
  537         DEVMETHOD(device_attach,        atdma_attach),
  538         DEVMETHOD(device_detach,        bus_generic_detach),
  539         DEVMETHOD(device_shutdown,      bus_generic_shutdown),
  540         DEVMETHOD(device_suspend,       bus_generic_suspend),
  541         DEVMETHOD(device_resume,        bus_generic_resume),
  542         { 0, 0 }
  543 };
  544 
  545 static driver_t atdma_driver = {
  546         "atdma",
  547         atdma_methods,
  548         1,              /* no softc */
  549 };
  550 
  551 static devclass_t atdma_devclass;
  552 
  553 DRIVER_MODULE(atdma, isa, atdma_driver, atdma_devclass, 0, 0);
  554 DRIVER_MODULE(atdma, acpi, atdma_driver, atdma_devclass, 0, 0);

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