FreeBSD/Linux Kernel Cross Reference
sys/x86/isa/isa_dma.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1991 The Regents of the University of California.
      * All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * William Jolitz.
      *
     * 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. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      from: @(#)isa.c 7.2 (Berkeley) 5/13/91
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    /*
     * code to manage AT bus
     *
     * 92/08/18  Frank P. MacLachlan (fpm@crash.cts.com):
     * Fixed uninitialized variable problem and added code to deal
     * with DMA page boundaries in isa_dmarangecheck().  Fixed word
     * mode DMA count compution and reorganized DMA setup code in
     * isa_dmastart()
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/lock.h>
    #include <sys/proc.h>
    #include <sys/mutex.h>
    #include <sys/module.h>
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <vm/pmap.h>
    #include <isa/isareg.h>
    #include <isa/isavar.h>
    #include <isa/isa_dmareg.h>
    
    #define ISARAM_END      0x1000000
    
    static int isa_dmarangecheck(caddr_t va, u_int length, int chan);
    
    static caddr_t  dma_bouncebuf[8];
    static u_int    dma_bouncebufsize[8];
    static u_int8_t dma_bounced = 0;
    static u_int8_t dma_busy = 0;           /* Used in isa_dmastart() */
    static u_int8_t dma_inuse = 0;          /* User for acquire/release */
    static u_int8_t dma_auto_mode = 0;
    static struct mtx isa_dma_lock;
    MTX_SYSINIT(isa_dma_lock, &isa_dma_lock, "isa DMA lock", MTX_DEF);
    
    #define VALID_DMA_MASK (7)
    
    /* high byte of address is stored in this port for i-th dma channel */
    static int dmapageport[8] = { 0x87, 0x83, 0x81, 0x82, 0x8f, 0x8b, 0x89, 0x8a };
    
    /*
     * Setup a DMA channel's bounce buffer.
     */
    int
    isa_dma_init(int chan, u_int bouncebufsize, int flag)
    {
            void *buf;
            int contig;
    
    #ifdef DIAGNOSTIC
            if (chan & ~VALID_DMA_MASK)
                    panic("isa_dma_init: channel out of range");
    #endif
    
    
            /* Try malloc() first.  It works better if it works. */
           buf = malloc(bouncebufsize, M_DEVBUF, flag);
           if (buf != NULL) {
                   if (isa_dmarangecheck(buf, bouncebufsize, chan) != 0) {
                           free(buf, M_DEVBUF);
                           buf = NULL;
                   }
                   contig = 0;
           }
   
           if (buf == NULL) {
                   buf = contigmalloc(bouncebufsize, M_DEVBUF, flag, 0ul, 0xfffffful,
                              1ul, chan & 4 ? 0x20000ul : 0x10000ul);
                   contig = 1;
           }
   
           if (buf == NULL)
                   return (ENOMEM);
   
           mtx_lock(&isa_dma_lock);
           /*
            * If a DMA channel is shared, both drivers have to call isa_dma_init
            * since they don't know that the other driver will do it.
            * Just return if we're already set up good.
            * XXX: this only works if they agree on the bouncebuf size.  This
            * XXX: is typically the case since they are multiple instances of
            * XXX: the same driver.
            */
           if (dma_bouncebuf[chan] != NULL) {
                   if (contig)
                           contigfree(buf, bouncebufsize, M_DEVBUF);
                   else
                           free(buf, M_DEVBUF);
                   mtx_unlock(&isa_dma_lock);
                   return (0);
           }
   
           dma_bouncebufsize[chan] = bouncebufsize;
           dma_bouncebuf[chan] = buf;
   
           mtx_unlock(&isa_dma_lock);
   
           return (0);
   }
   
   /*
    * Register a DMA channel's usage.  Usually called from a device driver
    * in open() or during its initialization.
    */
   int
   isa_dma_acquire(int chan)
   {
   #ifdef DIAGNOSTIC
           if (chan & ~VALID_DMA_MASK)
                   panic("isa_dma_acquire: channel out of range");
   #endif
   
           mtx_lock(&isa_dma_lock);
           if (dma_inuse & (1 << chan)) {
                   printf("isa_dma_acquire: channel %d already in use\n", chan);
                   mtx_unlock(&isa_dma_lock);
                   return (EBUSY);
           }
           dma_inuse |= (1 << chan);
           dma_auto_mode &= ~(1 << chan);
           mtx_unlock(&isa_dma_lock);
   
           return (0);
   }
   
   /*
    * Unregister a DMA channel's usage.  Usually called from a device driver
    * during close() or during its shutdown.
    */
   void
   isa_dma_release(int chan)
   {
   #ifdef DIAGNOSTIC
           if (chan & ~VALID_DMA_MASK)
                   panic("isa_dma_release: channel out of range");
   
           mtx_lock(&isa_dma_lock);
           if ((dma_inuse & (1 << chan)) == 0)
                   printf("isa_dma_release: channel %d not in use\n", chan);
   #else
           mtx_lock(&isa_dma_lock);
   #endif
   
           if (dma_busy & (1 << chan)) {
                   dma_busy &= ~(1 << chan);
                   /* 
                    * XXX We should also do "dma_bounced &= (1 << chan);"
                    * because we are acting on behalf of isa_dmadone() which
                    * was not called to end the last DMA operation.  This does
                    * not matter now, but it may in the future.
                    */
           }
   
           dma_inuse &= ~(1 << chan);
           dma_auto_mode &= ~(1 << chan);
   
           mtx_unlock(&isa_dma_lock);
   }
   
   /*
    * isa_dmacascade(): program 8237 DMA controller channel to accept
    * external dma control by a board.
    */
   void
   isa_dmacascade(int chan)
   {
   #ifdef DIAGNOSTIC
           if (chan & ~VALID_DMA_MASK)
                   panic("isa_dmacascade: channel out of range");
   #endif
   
           mtx_lock(&isa_dma_lock);
           /* set dma channel mode, and set dma channel mode */
           if ((chan & 4) == 0) {
                   outb(DMA1_MODE, DMA37MD_CASCADE | chan);
                   outb(DMA1_SMSK, chan);
           } else {
                   outb(DMA2_MODE, DMA37MD_CASCADE | (chan & 3));
                   outb(DMA2_SMSK, chan & 3);
           }
           mtx_unlock(&isa_dma_lock);
   }
   
   /*
    * isa_dmastart(): program 8237 DMA controller channel, avoid page alignment
    * problems by using a bounce buffer.
    */
   void
   isa_dmastart(int flags, caddr_t addr, u_int nbytes, int chan)
   {
           vm_paddr_t phys;
           int waport;
           caddr_t newaddr;
           int dma_range_checked;
   
           dma_range_checked = isa_dmarangecheck(addr, nbytes, chan);
   
   #ifdef DIAGNOSTIC
           if (chan & ~VALID_DMA_MASK)
                   panic("isa_dmastart: channel out of range");
   
           if ((chan < 4 && nbytes > (1<<16))
               || (chan >= 4 && (nbytes > (1<<17) || (uintptr_t)addr & 1)))
                   panic("isa_dmastart: impossible request");
   
           mtx_lock(&isa_dma_lock);
           if ((dma_inuse & (1 << chan)) == 0)
                   printf("isa_dmastart: channel %d not acquired\n", chan);
   #else
           mtx_lock(&isa_dma_lock);
   #endif
   
   #if 0
           /*
            * XXX This should be checked, but drivers like ad1848 only call
            * isa_dmastart() once because they use Auto DMA mode.  If we
            * leave this in, drivers that do this will print this continuously.
            */
           if (dma_busy & (1 << chan))
                   printf("isa_dmastart: channel %d busy\n", chan);
   #endif
   
           dma_busy |= (1 << chan);
   
           if (dma_range_checked) {
                   if (dma_bouncebuf[chan] == NULL
                       || dma_bouncebufsize[chan] < nbytes)
                           panic("isa_dmastart: bad bounce buffer"); 
                   dma_bounced |= (1 << chan);
                   newaddr = dma_bouncebuf[chan];
   
                   /* copy bounce buffer on write */
                   if (!(flags & ISADMA_READ))
                           bcopy(addr, newaddr, nbytes);
                   addr = newaddr;
           }
   
           /* translate to physical */
           phys = pmap_extract(kernel_pmap, (vm_offset_t)addr);
   
           if (flags & ISADMA_RAW) {
               dma_auto_mode |= (1 << chan);
           } else { 
               dma_auto_mode &= ~(1 << chan);
           }
   
           if ((chan & 4) == 0) {
                   /*
                    * Program one of DMA channels 0..3.  These are
                    * byte mode channels.
                    */
                   /* set dma channel mode, and reset address ff */
   
                   /* If ISADMA_RAW flag is set, then use autoinitialise mode */
                   if (flags & ISADMA_RAW) {
                     if (flags & ISADMA_READ)
                           outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_WRITE|chan);
                     else
                           outb(DMA1_MODE, DMA37MD_AUTO|DMA37MD_READ|chan);
                   }
                   else
                   if (flags & ISADMA_READ)
                           outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|chan);
                   else
                           outb(DMA1_MODE, DMA37MD_SINGLE|DMA37MD_READ|chan);
                   outb(DMA1_FFC, 0);
   
                   /* send start address */
                   waport =  DMA1_CHN(chan);
                   outb(waport, phys);
                   outb(waport, phys>>8);
                   outb(dmapageport[chan], phys>>16);
   
                   /* send count */
                   outb(waport + 1, --nbytes);
                   outb(waport + 1, nbytes>>8);
   
                   /* unmask channel */
                   outb(DMA1_SMSK, chan);
           } else {
                   /*
                    * Program one of DMA channels 4..7.  These are
                    * word mode channels.
                    */
                   /* set dma channel mode, and reset address ff */
   
                   /* If ISADMA_RAW flag is set, then use autoinitialise mode */
                   if (flags & ISADMA_RAW) {
                     if (flags & ISADMA_READ)
                           outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_WRITE|(chan&3));
                     else
                           outb(DMA2_MODE, DMA37MD_AUTO|DMA37MD_READ|(chan&3));
                   }
                   else
                   if (flags & ISADMA_READ)
                           outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_WRITE|(chan&3));
                   else
                           outb(DMA2_MODE, DMA37MD_SINGLE|DMA37MD_READ|(chan&3));
                   outb(DMA2_FFC, 0);
   
                   /* send start address */
                   waport = DMA2_CHN(chan - 4);
                   outb(waport, phys>>1);
                   outb(waport, phys>>9);
                   outb(dmapageport[chan], phys>>16);
   
                   /* send count */
                   nbytes >>= 1;
                   outb(waport + 2, --nbytes);
                   outb(waport + 2, nbytes>>8);
   
                   /* unmask channel */
                   outb(DMA2_SMSK, chan & 3);
           }
           mtx_unlock(&isa_dma_lock);
   }
   
   void
   isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
   {  
   #ifdef DIAGNOSTIC
           if (chan & ~VALID_DMA_MASK)
                   panic("isa_dmadone: channel out of range");
   
           if ((dma_inuse & (1 << chan)) == 0)
                   printf("isa_dmadone: channel %d not acquired\n", chan);
   #endif
   
           mtx_lock(&isa_dma_lock);
           if (((dma_busy & (1 << chan)) == 0) && 
               (dma_auto_mode & (1 << chan)) == 0 )
                   printf("isa_dmadone: channel %d not busy\n", chan);
   
           if ((dma_auto_mode & (1 << chan)) == 0)
                   outb(chan & 4 ? DMA2_SMSK : DMA1_SMSK, (chan & 3) | 4);
   
           if (dma_bounced & (1 << chan)) {
                   /* copy bounce buffer on read */
                   if (flags & ISADMA_READ)
                           bcopy(dma_bouncebuf[chan], addr, nbytes);
   
                   dma_bounced &= ~(1 << chan);
           }
           dma_busy &= ~(1 << chan);
           mtx_unlock(&isa_dma_lock);
   }
   
   /*
    * Check for problems with the address range of a DMA transfer
    * (non-contiguous physical pages, outside of bus address space,
    * crossing DMA page boundaries).
    * Return true if special handling needed.
    */
   
   static int
   isa_dmarangecheck(caddr_t va, u_int length, int chan)
   {
           vm_paddr_t phys, priorpage = 0;
           vm_offset_t endva;
           u_int dma_pgmsk = (chan & 4) ?  ~(128*1024-1) : ~(64*1024-1);
   
           endva = (vm_offset_t)round_page((vm_offset_t)va + length);
           for (; va < (caddr_t) endva ; va += PAGE_SIZE) {
                   phys = trunc_page(pmap_extract(kernel_pmap, (vm_offset_t)va));
                   if (phys == 0)
                           panic("isa_dmacheck: no physical page present");
                   if (phys >= ISARAM_END)
                           return (1);
                   if (priorpage) {
                           if (priorpage + PAGE_SIZE != phys)
                                   return (1);
                           /* check if crossing a DMA page boundary */
                           if (((u_int)priorpage ^ (u_int)phys) & dma_pgmsk)
                                   return (1);
                   }
                   priorpage = phys;
           }
           return (0);
   }
   
   /*
    * Query the progress of a transfer on a DMA channel.
    *
    * To avoid having to interrupt a transfer in progress, we sample
    * each of the high and low databytes twice, and apply the following
    * logic to determine the correct count.
    *
    * Reads are performed with interrupts disabled, thus it is to be
    * expected that the time between reads is very small.  At most
    * one rollover in the low count byte can be expected within the
    * four reads that are performed.
    *
    * There are three gaps in which a rollover can occur :
    *
    * - read low1
    *              gap1
    * - read high1
    *              gap2
    * - read low2
    *              gap3
    * - read high2
    *
    * If a rollover occurs in gap1 or gap2, the low2 value will be
    * greater than the low1 value.  In this case, low2 and high2 are a
    * corresponding pair. 
    *
    * In any other case, low1 and high1 can be considered to be correct.
    *
    * The function returns the number of bytes remaining in the transfer,
    * or -1 if the channel requested is not active.
    *
    */
   static int
   isa_dmastatus_locked(int chan)
   {
           u_long  cnt = 0;
           int     ffport, waport;
           u_long  low1, high1, low2, high2;
   
           mtx_assert(&isa_dma_lock, MA_OWNED);
   
           /* channel active? */
           if ((dma_inuse & (1 << chan)) == 0) {
                   printf("isa_dmastatus: channel %d not active\n", chan);
                   return(-1);
           }
           /* channel busy? */
   
           if (((dma_busy & (1 << chan)) == 0) &&
               (dma_auto_mode & (1 << chan)) == 0 ) {
               printf("chan %d not busy\n", chan);
               return -2 ;
           }       
           if (chan < 4) {                 /* low DMA controller */
                   ffport = DMA1_FFC;
                   waport = DMA1_CHN(chan) + 1;
           } else {                        /* high DMA controller */
                   ffport = DMA2_FFC;
                   waport = DMA2_CHN(chan - 4) + 2;
           }
   
           disable_intr();                 /* no interrupts Mr Jones! */
           outb(ffport, 0);                /* clear register LSB flipflop */
           low1 = inb(waport);
           high1 = inb(waport);
           outb(ffport, 0);                /* clear again */
           low2 = inb(waport);
           high2 = inb(waport);
           enable_intr();                  /* enable interrupts again */
   
           /* 
            * Now decide if a wrap has tried to skew our results.
            * Note that after TC, the count will read 0xffff, while we want 
            * to return zero, so we add and then mask to compensate.
            */
           if (low1 >= low2) {
                   cnt = (low1 + (high1 << 8) + 1) & 0xffff;
           } else {
                   cnt = (low2 + (high2 << 8) + 1) & 0xffff;
           }
   
           if (chan >= 4)                  /* high channels move words */
                   cnt *= 2;
           return(cnt);
   }
   
   int
   isa_dmastatus(int chan)
   {
           int status;
   
           mtx_lock(&isa_dma_lock);
           status = isa_dmastatus_locked(chan);
           mtx_unlock(&isa_dma_lock);
   
           return (status);
   }
   
   /*
    * Reached terminal count yet ?
    */
   int
   isa_dmatc(int chan)
   {
   
           if (chan < 4)
                   return(inb(DMA1_STATUS) & (1 << chan));
           else
                   return(inb(DMA2_STATUS) & (1 << (chan & 3)));
   }
   
   /*
    * Stop a DMA transfer currently in progress.
    */
   int
   isa_dmastop(int chan) 
   {
           int status;
   
           mtx_lock(&isa_dma_lock);
           if ((dma_inuse & (1 << chan)) == 0)
                   printf("isa_dmastop: channel %d not acquired\n", chan);  
   
           if (((dma_busy & (1 << chan)) == 0) &&
               ((dma_auto_mode & (1 << chan)) == 0)) {
                   printf("chan %d not busy\n", chan);
                   mtx_unlock(&isa_dma_lock);
                   return -2 ;
           }
       
           if ((chan & 4) == 0) {
                   outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
           } else {
                   outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
           }
   
           status = isa_dmastatus_locked(chan);
   
           mtx_unlock(&isa_dma_lock);
   
           return (status);
   }
   
   /*
    * Attach to the ISA PnP descriptor for the AT DMA controller
    */
   static struct isa_pnp_id atdma_ids[] = {
           { 0x0002d041 /* PNP0200 */, "AT DMA controller" },
           { 0 }
   };
   
   static int
   atdma_probe(device_t dev)
   {
           int result;
           
           if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, atdma_ids)) <= 0)
                   device_quiet(dev);
           return(result);
   }
   
   static int
   atdma_attach(device_t dev)
   {
           return(0);
   }
   
   static device_method_t atdma_methods[] = {
           /* Device interface */
           DEVMETHOD(device_probe,         atdma_probe),
           DEVMETHOD(device_attach,        atdma_attach),
           DEVMETHOD(device_detach,        bus_generic_detach),
           DEVMETHOD(device_shutdown,      bus_generic_shutdown),
           DEVMETHOD(device_suspend,       bus_generic_suspend),
           DEVMETHOD(device_resume,        bus_generic_resume),
           { 0, 0 }
   };
   
   static driver_t atdma_driver = {
           "atdma",
           atdma_methods,
           1,              /* no softc */
   };
   
   static devclass_t atdma_devclass;
   
   DRIVER_MODULE(atdma, isa, atdma_driver, atdma_devclass, 0, 0);
   DRIVER_MODULE(atdma, acpi, atdma_driver, atdma_devclass, 0, 0);
   ISA_PNP_INFO(atdma_ids);

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