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

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    1 /*-
    2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions, and the following disclaimer,
   10  *    without modification, immediately at the beginning of the file.
   11  * 2. The name of the author may not be used to endorse or promote products
   12  *    derived from this software without specific prior written permission.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
   18  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 /*
   28  * From amd64/busdma_machdep.c, r204214
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD: releng/10.2/sys/powerpc/powerpc/busdma_machdep.c 282506 2015-05-05 19:47:17Z hselasky $");
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/malloc.h>
   37 #include <sys/bus.h>
   38 #include <sys/interrupt.h>
   39 #include <sys/kernel.h>
   40 #include <sys/ktr.h>
   41 #include <sys/lock.h>
   42 #include <sys/proc.h>
   43 #include <sys/memdesc.h>
   44 #include <sys/mutex.h>
   45 #include <sys/sysctl.h>
   46 #include <sys/uio.h>
   47 
   48 #include <vm/vm.h>
   49 #include <vm/vm_extern.h>
   50 #include <vm/vm_kern.h>
   51 #include <vm/vm_page.h>
   52 #include <vm/vm_map.h>
   53 
   54 #include <machine/atomic.h>
   55 #include <machine/bus.h>
   56 #include <machine/cpufunc.h>
   57 #include <machine/md_var.h>
   58 
   59 #include "iommu_if.h"
   60 
   61 #define MAX_BPAGES MIN(8192, physmem/40)
   62 
   63 struct bounce_zone;
   64 
   65 struct bus_dma_tag {
   66         bus_dma_tag_t     parent;
   67         bus_size_t        alignment;
   68         bus_addr_t        boundary;
   69         bus_addr_t        lowaddr;
   70         bus_addr_t        highaddr;
   71         bus_dma_filter_t *filter;
   72         void             *filterarg;
   73         bus_size_t        maxsize;
   74         u_int             nsegments;
   75         bus_size_t        maxsegsz;
   76         int               flags;
   77         int               ref_count;
   78         int               map_count;
   79         bus_dma_lock_t   *lockfunc;
   80         void             *lockfuncarg;
   81         struct bounce_zone *bounce_zone;
   82         device_t          iommu;
   83         void             *iommu_cookie;
   84 };
   85 
   86 struct bounce_page {
   87         vm_offset_t     vaddr;          /* kva of bounce buffer */
   88         bus_addr_t      busaddr;        /* Physical address */
   89         vm_offset_t     datavaddr;      /* kva of client data */
   90         bus_addr_t      dataaddr;       /* client physical address */
   91         bus_size_t      datacount;      /* client data count */
   92         STAILQ_ENTRY(bounce_page) links;
   93 };
   94 
   95 int busdma_swi_pending;
   96 
   97 struct bounce_zone {
   98         STAILQ_ENTRY(bounce_zone) links;
   99         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  100         int             total_bpages;
  101         int             free_bpages;
  102         int             reserved_bpages;
  103         int             active_bpages;
  104         int             total_bounced;
  105         int             total_deferred;
  106         int             map_count;
  107         bus_size_t      alignment;
  108         bus_addr_t      lowaddr;
  109         char            zoneid[8];
  110         char            lowaddrid[20];
  111         struct sysctl_ctx_list sysctl_tree;
  112         struct sysctl_oid *sysctl_tree_top;
  113 };
  114 
  115 static struct mtx bounce_lock;
  116 static int total_bpages;
  117 static int busdma_zonecount;
  118 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
  119 
  120 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
  121 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
  122            "Total bounce pages");
  123 
  124 struct bus_dmamap {
  125         struct bp_list         bpages;
  126         int                    pagesneeded;
  127         int                    pagesreserved;
  128         bus_dma_tag_t          dmat;
  129         struct memdesc         mem;
  130         bus_dma_segment_t     *segments;
  131         int                    nsegs;
  132         bus_dmamap_callback_t *callback;
  133         void                  *callback_arg;
  134         STAILQ_ENTRY(bus_dmamap) links;
  135         int                    contigalloc;
  136 };
  137 
  138 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
  139 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
  140 
  141 static void init_bounce_pages(void *dummy);
  142 static int alloc_bounce_zone(bus_dma_tag_t dmat);
  143 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
  144 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
  145                                 int commit);
  146 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
  147                                   vm_offset_t vaddr, bus_addr_t addr,
  148                                   bus_size_t size);
  149 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
  150 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
  151 
  152 /*
  153  * Return true if a match is made.
  154  *
  155  * To find a match walk the chain of bus_dma_tag_t's looking for 'paddr'.
  156  *
  157  * If paddr is within the bounds of the dma tag then call the filter callback
  158  * to check for a match, if there is no filter callback then assume a match.
  159  */
  160 static __inline int
  161 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
  162 {
  163         int retval;
  164 
  165         retval = 0;
  166 
  167         do {
  168                 if (dmat->filter == NULL && dmat->iommu == NULL &&
  169                     paddr > dmat->lowaddr && paddr <= dmat->highaddr)
  170                         retval = 1;
  171                 if (dmat->filter == NULL &&
  172                     (paddr & (dmat->alignment - 1)) != 0)
  173                         retval = 1;
  174                 if (dmat->filter != NULL &&
  175                     (*dmat->filter)(dmat->filterarg, paddr) != 0)
  176                         retval = 1;
  177 
  178                 dmat = dmat->parent;            
  179         } while (retval == 0 && dmat != NULL);
  180         return (retval);
  181 }
  182 
  183 /*
  184  * Convenience function for manipulating driver locks from busdma (during
  185  * busdma_swi, for example).  Drivers that don't provide their own locks
  186  * should specify &Giant to dmat->lockfuncarg.  Drivers that use their own
  187  * non-mutex locking scheme don't have to use this at all.
  188  */
  189 void
  190 busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
  191 {
  192         struct mtx *dmtx;
  193 
  194         dmtx = (struct mtx *)arg;
  195         switch (op) {
  196         case BUS_DMA_LOCK:
  197                 mtx_lock(dmtx);
  198                 break;
  199         case BUS_DMA_UNLOCK:
  200                 mtx_unlock(dmtx);
  201                 break;
  202         default:
  203                 panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
  204         }
  205 }
  206 
  207 /*
  208  * dflt_lock should never get called.  It gets put into the dma tag when
  209  * lockfunc == NULL, which is only valid if the maps that are associated
  210  * with the tag are meant to never be defered.
  211  * XXX Should have a way to identify which driver is responsible here.
  212  */
  213 static void
  214 dflt_lock(void *arg, bus_dma_lock_op_t op)
  215 {
  216         panic("driver error: busdma dflt_lock called");
  217 }
  218 
  219 #define BUS_DMA_COULD_BOUNCE    BUS_DMA_BUS3
  220 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  221 /*
  222  * Allocate a device specific dma_tag.
  223  */
  224 int
  225 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
  226                    bus_addr_t boundary, bus_addr_t lowaddr,
  227                    bus_addr_t highaddr, bus_dma_filter_t *filter,
  228                    void *filterarg, bus_size_t maxsize, int nsegments,
  229                    bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
  230                    void *lockfuncarg, bus_dma_tag_t *dmat)
  231 {
  232         bus_dma_tag_t newtag;
  233         int error = 0;
  234 
  235         /* Basic sanity checking */
  236         if (boundary != 0 && boundary < maxsegsz)
  237                 maxsegsz = boundary;
  238 
  239         if (maxsegsz == 0) {
  240                 return (EINVAL);
  241         }
  242 
  243         /* Return a NULL tag on failure */
  244         *dmat = NULL;
  245 
  246         newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF,
  247             M_ZERO | M_NOWAIT);
  248         if (newtag == NULL) {
  249                 CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
  250                     __func__, newtag, 0, error);
  251                 return (ENOMEM);
  252         }
  253 
  254         newtag->parent = parent;
  255         newtag->alignment = alignment;
  256         newtag->boundary = boundary;
  257         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
  258         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
  259         newtag->filter = filter;
  260         newtag->filterarg = filterarg;
  261         newtag->maxsize = maxsize;
  262         newtag->nsegments = nsegments;
  263         newtag->maxsegsz = maxsegsz;
  264         newtag->flags = flags;
  265         newtag->ref_count = 1; /* Count ourself */
  266         newtag->map_count = 0;
  267         if (lockfunc != NULL) {
  268                 newtag->lockfunc = lockfunc;
  269                 newtag->lockfuncarg = lockfuncarg;
  270         } else {
  271                 newtag->lockfunc = dflt_lock;
  272                 newtag->lockfuncarg = NULL;
  273         }
  274 
  275         /* Take into account any restrictions imposed by our parent tag */
  276         if (parent != NULL) {
  277                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
  278                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
  279                 if (newtag->boundary == 0)
  280                         newtag->boundary = parent->boundary;
  281                 else if (parent->boundary != 0)
  282                         newtag->boundary = MIN(parent->boundary,
  283                                                newtag->boundary);
  284                 if (newtag->filter == NULL) {
  285                         /*
  286                          * Short circuit looking at our parent directly
  287                          * since we have encapsulated all of its information
  288                          */
  289                         newtag->filter = parent->filter;
  290                         newtag->filterarg = parent->filterarg;
  291                         newtag->parent = parent->parent;
  292                 }
  293                 if (newtag->parent != NULL)
  294                         atomic_add_int(&parent->ref_count, 1);
  295                 newtag->iommu = parent->iommu;
  296                 newtag->iommu_cookie = parent->iommu_cookie;
  297         }
  298 
  299         if (newtag->lowaddr < ptoa((vm_paddr_t)Maxmem) && newtag->iommu == NULL)
  300                 newtag->flags |= BUS_DMA_COULD_BOUNCE;
  301 
  302         if (newtag->alignment > 1)
  303                 newtag->flags |= BUS_DMA_COULD_BOUNCE;
  304 
  305         if (((newtag->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
  306             (flags & BUS_DMA_ALLOCNOW) != 0) {
  307                 struct bounce_zone *bz;
  308 
  309                 /* Must bounce */
  310 
  311                 if ((error = alloc_bounce_zone(newtag)) != 0) {
  312                         free(newtag, M_DEVBUF);
  313                         return (error);
  314                 }
  315                 bz = newtag->bounce_zone;
  316 
  317                 if (ptoa(bz->total_bpages) < maxsize) {
  318                         int pages;
  319 
  320                         pages = atop(maxsize) - bz->total_bpages;
  321 
  322                         /* Add pages to our bounce pool */
  323                         if (alloc_bounce_pages(newtag, pages) < pages)
  324                                 error = ENOMEM;
  325                 }
  326                 /* Performed initial allocation */
  327                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
  328         }
  329         
  330         if (error != 0) {
  331                 free(newtag, M_DEVBUF);
  332         } else {
  333                 *dmat = newtag;
  334         }
  335         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
  336             __func__, newtag, (newtag != NULL ? newtag->flags : 0), error);
  337         return (error);
  338 }
  339 
  340 int
  341 bus_dma_tag_destroy(bus_dma_tag_t dmat)
  342 {
  343         bus_dma_tag_t dmat_copy;
  344         int error;
  345 
  346         error = 0;
  347         dmat_copy = dmat;
  348 
  349         if (dmat != NULL) {
  350 
  351                 if (dmat->map_count != 0) {
  352                         error = EBUSY;
  353                         goto out;
  354                 }
  355 
  356                 while (dmat != NULL) {
  357                         bus_dma_tag_t parent;
  358 
  359                         parent = dmat->parent;
  360                         atomic_subtract_int(&dmat->ref_count, 1);
  361                         if (dmat->ref_count == 0) {
  362                                 free(dmat, M_DEVBUF);
  363                                 /*
  364                                  * Last reference count, so
  365                                  * release our reference
  366                                  * count on our parent.
  367                                  */
  368                                 dmat = parent;
  369                         } else
  370                                 dmat = NULL;
  371                 }
  372         }
  373 out:
  374         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
  375         return (error);
  376 }
  377 
  378 /*
  379  * Allocate a handle for mapping from kva/uva/physical
  380  * address space into bus device space.
  381  */
  382 int
  383 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
  384 {
  385         int error;
  386 
  387         error = 0;
  388 
  389         *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
  390                                      M_NOWAIT | M_ZERO);
  391         if (*mapp == NULL) {
  392                 CTR3(KTR_BUSDMA, "%s: tag %p error %d",
  393                     __func__, dmat, ENOMEM);
  394                 return (ENOMEM);
  395         }
  396 
  397 
  398         /*
  399          * Bouncing might be required if the driver asks for an active
  400          * exclusion region, a data alignment that is stricter than 1, and/or
  401          * an active address boundary.
  402          */
  403         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
  404 
  405                 /* Must bounce */
  406                 struct bounce_zone *bz;
  407                 int maxpages;
  408 
  409                 if (dmat->bounce_zone == NULL) {
  410                         if ((error = alloc_bounce_zone(dmat)) != 0)
  411                                 return (error);
  412                 }
  413                 bz = dmat->bounce_zone;
  414 
  415                 /* Initialize the new map */
  416                 STAILQ_INIT(&((*mapp)->bpages));
  417 
  418                 /*
  419                  * Attempt to add pages to our pool on a per-instance
  420                  * basis up to a sane limit.
  421                  */
  422                 if (dmat->alignment > 1)
  423                         maxpages = MAX_BPAGES;
  424                 else
  425                         maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
  426                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
  427                  || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
  428                         int pages;
  429 
  430                         pages = MAX(atop(dmat->maxsize), 1);
  431                         pages = MIN(maxpages - bz->total_bpages, pages);
  432                         pages = MAX(pages, 1);
  433                         if (alloc_bounce_pages(dmat, pages) < pages)
  434                                 error = ENOMEM;
  435 
  436                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
  437                                 if (error == 0)
  438                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
  439                         } else {
  440                                 error = 0;
  441                         }
  442                 }
  443                 bz->map_count++;
  444         }
  445 
  446         (*mapp)->nsegs = 0;
  447         (*mapp)->segments = (bus_dma_segment_t *)malloc(
  448             sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
  449             M_NOWAIT);
  450         if ((*mapp)->segments == NULL) {
  451                 CTR3(KTR_BUSDMA, "%s: tag %p error %d",
  452                     __func__, dmat, ENOMEM);
  453                 return (ENOMEM);
  454         }
  455 
  456         if (error == 0)
  457                 dmat->map_count++;
  458         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
  459             __func__, dmat, dmat->flags, error);
  460         return (error);
  461 }
  462 
  463 /*
  464  * Destroy a handle for mapping from kva/uva/physical
  465  * address space into bus device space.
  466  */
  467 int
  468 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
  469 {
  470         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
  471                 if (STAILQ_FIRST(&map->bpages) != NULL) {
  472                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
  473                             __func__, dmat, EBUSY);
  474                         return (EBUSY);
  475                 }
  476                 if (dmat->bounce_zone)
  477                         dmat->bounce_zone->map_count--;
  478         }
  479         free(map->segments, M_DEVBUF);
  480         free(map, M_DEVBUF);
  481         dmat->map_count--;
  482         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
  483         return (0);
  484 }
  485 
  486 
  487 /*
  488  * Allocate a piece of memory that can be efficiently mapped into
  489  * bus device space based on the constraints lited in the dma tag.
  490  * A dmamap to for use with dmamap_load is also allocated.
  491  */
  492 int
  493 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  494                  bus_dmamap_t *mapp)
  495 {
  496         vm_memattr_t attr;
  497         int mflags;
  498 
  499         if (flags & BUS_DMA_NOWAIT)
  500                 mflags = M_NOWAIT;
  501         else
  502                 mflags = M_WAITOK;
  503 
  504         bus_dmamap_create(dmat, flags, mapp);
  505 
  506         if (flags & BUS_DMA_ZERO)
  507                 mflags |= M_ZERO;
  508 #ifdef NOTYET
  509         if (flags & BUS_DMA_NOCACHE)
  510                 attr = VM_MEMATTR_UNCACHEABLE;
  511         else
  512 #endif
  513                 attr = VM_MEMATTR_DEFAULT;
  514 
  515         /* 
  516          * XXX:
  517          * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
  518          * alignment guarantees of malloc need to be nailed down, and the
  519          * code below should be rewritten to take that into account.
  520          *
  521          * In the meantime, we'll warn the user if malloc gets it wrong.
  522          */
  523         if ((dmat->maxsize <= PAGE_SIZE) &&
  524            (dmat->alignment < dmat->maxsize) &&
  525             dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
  526             attr == VM_MEMATTR_DEFAULT) {
  527                 *vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
  528         } else {
  529                 /*
  530                  * XXX Use Contigmalloc until it is merged into this facility
  531                  *     and handles multi-seg allocations.  Nobody is doing
  532                  *     multi-seg allocations yet though.
  533                  * XXX Certain AGP hardware does.
  534                  */
  535                 *vaddr = (void *)kmem_alloc_contig(kmem_arena, dmat->maxsize,
  536                     mflags, 0ul, dmat->lowaddr, dmat->alignment ?
  537                     dmat->alignment : 1ul, dmat->boundary, attr);
  538                 (*mapp)->contigalloc = 1;
  539         }
  540         if (*vaddr == NULL) {
  541                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
  542                     __func__, dmat, dmat->flags, ENOMEM);
  543                 return (ENOMEM);
  544         } else if (vtophys(*vaddr) & (dmat->alignment - 1)) {
  545                 printf("bus_dmamem_alloc failed to align memory properly.\n");
  546         }
  547         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
  548             __func__, dmat, dmat->flags, 0);
  549         return (0);
  550 }
  551 
  552 /*
  553  * Free a piece of memory and it's allociated dmamap, that was allocated
  554  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
  555  */
  556 void
  557 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
  558 {
  559 
  560         if (!map->contigalloc)
  561                 free(vaddr, M_DEVBUF);
  562         else
  563                 kmem_free(kmem_arena, (vm_offset_t)vaddr, dmat->maxsize);
  564         bus_dmamap_destroy(dmat, map);
  565         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
  566 }
  567 
  568 static void
  569 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
  570     bus_size_t buflen, int flags)
  571 {
  572         bus_addr_t curaddr;
  573         bus_size_t sgsize;
  574 
  575         if (map->pagesneeded == 0) {
  576                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
  577                     "alignment= %d", dmat->lowaddr, ptoa((vm_paddr_t)Maxmem),
  578                     dmat->boundary, dmat->alignment);
  579                 CTR2(KTR_BUSDMA, "map= %p, pagesneeded= %d", map, map->pagesneeded);
  580                 /*
  581                  * Count the number of bounce pages
  582                  * needed in order to complete this transfer
  583                  */
  584                 curaddr = buf;
  585                 while (buflen != 0) {
  586                         sgsize = MIN(buflen, dmat->maxsegsz);
  587                         if (run_filter(dmat, curaddr) != 0) {
  588                                 sgsize = MIN(sgsize, PAGE_SIZE);
  589                                 map->pagesneeded++;
  590                         }
  591                         curaddr += sgsize;
  592                         buflen -= sgsize;
  593                 }
  594                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
  595         }
  596 }
  597 
  598 static void
  599 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
  600     void *buf, bus_size_t buflen, int flags)
  601 {
  602         vm_offset_t vaddr;
  603         vm_offset_t vendaddr;
  604         bus_addr_t paddr;
  605 
  606         if (map->pagesneeded == 0) {
  607                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
  608                     "alignment= %d", dmat->lowaddr, ptoa((vm_paddr_t)Maxmem),
  609                     dmat->boundary, dmat->alignment);
  610                 CTR2(KTR_BUSDMA, "map= %p, pagesneeded= %d", map, map->pagesneeded);
  611                 /*
  612                  * Count the number of bounce pages
  613                  * needed in order to complete this transfer
  614                  */
  615                 vaddr = (vm_offset_t)buf;
  616                 vendaddr = (vm_offset_t)buf + buflen;
  617 
  618                 while (vaddr < vendaddr) {
  619                         bus_size_t sg_len;
  620 
  621                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
  622                         if (pmap == kernel_pmap)
  623                                 paddr = pmap_kextract(vaddr);
  624                         else
  625                                 paddr = pmap_extract(pmap, vaddr);
  626                         if (run_filter(dmat, paddr) != 0) {
  627                                 sg_len = roundup2(sg_len, dmat->alignment);
  628                                 map->pagesneeded++;
  629                         }
  630                         vaddr += sg_len;
  631                 }
  632                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
  633         }
  634 }
  635 
  636 static int
  637 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
  638 {
  639 
  640         /* Reserve Necessary Bounce Pages */
  641         mtx_lock(&bounce_lock);
  642         if (flags & BUS_DMA_NOWAIT) {
  643                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
  644                         mtx_unlock(&bounce_lock);
  645                         return (ENOMEM);
  646                 }
  647         } else {
  648                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
  649                         /* Queue us for resources */
  650                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist,
  651                             map, links);
  652                         mtx_unlock(&bounce_lock);
  653                         return (EINPROGRESS);
  654                 }
  655         }
  656         mtx_unlock(&bounce_lock);
  657 
  658         return (0);
  659 }
  660 
  661 /*
  662  * Add a single contiguous physical range to the segment list.
  663  */
  664 static int
  665 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
  666                    bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
  667 {
  668         bus_addr_t baddr, bmask;
  669         int seg;
  670 
  671         /*
  672          * Make sure we don't cross any boundaries.
  673          */
  674         bmask = ~(dmat->boundary - 1);
  675         if (dmat->boundary > 0) {
  676                 baddr = (curaddr + dmat->boundary) & bmask;
  677                 if (sgsize > (baddr - curaddr))
  678                         sgsize = (baddr - curaddr);
  679         }
  680 
  681         /*
  682          * Insert chunk into a segment, coalescing with
  683          * previous segment if possible.
  684          */
  685         seg = *segp;
  686         if (seg == -1) {
  687                 seg = 0;
  688                 segs[seg].ds_addr = curaddr;
  689                 segs[seg].ds_len = sgsize;
  690         } else {
  691                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
  692                     (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
  693                     (dmat->boundary == 0 ||
  694                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
  695                         segs[seg].ds_len += sgsize;
  696                 else {
  697                         if (++seg >= dmat->nsegments)
  698                                 return (0);
  699                         segs[seg].ds_addr = curaddr;
  700                         segs[seg].ds_len = sgsize;
  701                 }
  702         }
  703         *segp = seg;
  704         return (sgsize);
  705 }
  706 
  707 /*
  708  * Utility function to load a physical buffer.  segp contains
  709  * the starting segment on entrace, and the ending segment on exit.
  710  */
  711 int
  712 _bus_dmamap_load_phys(bus_dma_tag_t dmat,
  713                       bus_dmamap_t map,
  714                       vm_paddr_t buf, bus_size_t buflen,
  715                       int flags,
  716                       bus_dma_segment_t *segs,
  717                       int *segp)
  718 {
  719         bus_addr_t curaddr;
  720         bus_size_t sgsize;
  721         int error;
  722 
  723         if (segs == NULL)
  724                 segs = map->segments;
  725 
  726         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
  727                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
  728                 if (map->pagesneeded != 0) {
  729                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
  730                         if (error)
  731                                 return (error);
  732                 }
  733         }
  734 
  735         while (buflen > 0) {
  736                 curaddr = buf;
  737                 sgsize = MIN(buflen, dmat->maxsegsz);
  738                 if (map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
  739                         sgsize = MIN(sgsize, PAGE_SIZE);
  740                         curaddr = add_bounce_page(dmat, map, 0, curaddr,
  741                             sgsize);
  742                 }
  743                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
  744                     segp);
  745                 if (sgsize == 0)
  746                         break;
  747                 buf += sgsize;
  748                 buflen -= sgsize;
  749         }
  750 
  751         /*
  752          * Did we fit?
  753          */
  754         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
  755 }
  756 
  757 int
  758 _bus_dmamap_load_ma(bus_dma_tag_t dmat, bus_dmamap_t map,
  759     struct vm_page **ma, bus_size_t tlen, int ma_offs, int flags,
  760     bus_dma_segment_t *segs, int *segp)
  761 {
  762 
  763         return (bus_dmamap_load_ma_triv(dmat, map, ma, tlen, ma_offs, flags,
  764             segs, segp));
  765 }
  766 
  767 /*
  768  * Utility function to load a linear buffer.  segp contains
  769  * the starting segment on entrance, and the ending segment on exit.
  770  */
  771 int
  772 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
  773                         bus_dmamap_t map,
  774                         void *buf, bus_size_t buflen,
  775                         pmap_t pmap,
  776                         int flags,
  777                         bus_dma_segment_t *segs,
  778                         int *segp)
  779 {
  780         bus_size_t sgsize;
  781         bus_addr_t curaddr;
  782         vm_offset_t vaddr;
  783         int error;
  784 
  785         if (segs == NULL)
  786                 segs = map->segments;
  787 
  788         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
  789                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
  790                 if (map->pagesneeded != 0) {
  791                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
  792                         if (error)
  793                                 return (error);
  794                 }
  795         }
  796 
  797         vaddr = (vm_offset_t)buf;
  798 
  799         while (buflen > 0) {
  800                 bus_size_t max_sgsize;
  801 
  802                 /*
  803                  * Get the physical address for this segment.
  804                  */
  805                 if (pmap == kernel_pmap)
  806                         curaddr = pmap_kextract(vaddr);
  807                 else
  808                         curaddr = pmap_extract(pmap, vaddr);
  809 
  810                 /*
  811                  * Compute the segment size, and adjust counts.
  812                  */
  813                 max_sgsize = MIN(buflen, dmat->maxsegsz);
  814                 sgsize = PAGE_SIZE - ((vm_offset_t)curaddr & PAGE_MASK);
  815                 if (map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
  816                         sgsize = roundup2(sgsize, dmat->alignment);
  817                         sgsize = MIN(sgsize, max_sgsize);
  818                         curaddr = add_bounce_page(dmat, map, vaddr, curaddr,
  819                             sgsize);
  820                 } else {
  821                         sgsize = MIN(sgsize, max_sgsize);
  822                 }
  823 
  824                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
  825                     segp);
  826                 if (sgsize == 0)
  827                         break;
  828                 vaddr += sgsize;
  829                 buflen -= sgsize;
  830         }
  831 
  832         /*
  833          * Did we fit?
  834          */
  835         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
  836 }
  837 
  838 void
  839 __bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
  840                     struct memdesc *mem, bus_dmamap_callback_t *callback,
  841                     void *callback_arg)
  842 {
  843 
  844         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
  845                 map->dmat = dmat;
  846                 map->mem = *mem;
  847                 map->callback = callback;
  848                 map->callback_arg = callback_arg;
  849         }
  850 }
  851 
  852 bus_dma_segment_t *
  853 _bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
  854                      bus_dma_segment_t *segs, int nsegs, int error)
  855 {
  856 
  857         map->nsegs = nsegs;
  858         if (segs != NULL)
  859                 memcpy(map->segments, segs, map->nsegs*sizeof(segs[0]));
  860         if (dmat->iommu != NULL)
  861                 IOMMU_MAP(dmat->iommu, map->segments, &map->nsegs,
  862                     dmat->lowaddr, dmat->highaddr, dmat->alignment,
  863                     dmat->boundary, dmat->iommu_cookie);
  864 
  865         if (segs != NULL)
  866                 memcpy(segs, map->segments, map->nsegs*sizeof(segs[0]));
  867         else
  868                 segs = map->segments;
  869 
  870         return (segs);
  871 }
  872 
  873 /*
  874  * Release the mapping held by map.
  875  */
  876 void
  877 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
  878 {
  879         struct bounce_page *bpage;
  880 
  881         if (dmat->iommu) {
  882                 IOMMU_UNMAP(dmat->iommu, map->segments, map->nsegs, dmat->iommu_cookie);
  883                 map->nsegs = 0;
  884         }
  885 
  886         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
  887                 STAILQ_REMOVE_HEAD(&map->bpages, links);
  888                 free_bounce_page(dmat, bpage);
  889         }
  890 }
  891 
  892 void
  893 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
  894 {
  895         struct bounce_page *bpage;
  896 
  897         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
  898                 /*
  899                  * Handle data bouncing.  We might also
  900                  * want to add support for invalidating
  901                  * the caches on broken hardware
  902                  */
  903                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
  904                     "performing bounce", __func__, dmat, dmat->flags, op);
  905 
  906                 if (op & BUS_DMASYNC_PREWRITE) {
  907                         while (bpage != NULL) {
  908                                 if (bpage->datavaddr != 0)
  909                                         bcopy((void *)bpage->datavaddr,
  910                                               (void *)bpage->vaddr,
  911                                               bpage->datacount);
  912                                 else
  913                                         physcopyout(bpage->dataaddr,
  914                                             (void *)bpage->vaddr,
  915                                             bpage->datacount);
  916                                 bpage = STAILQ_NEXT(bpage, links);
  917                         }
  918                         dmat->bounce_zone->total_bounced++;
  919                 }
  920 
  921                 if (op & BUS_DMASYNC_POSTREAD) {
  922                         while (bpage != NULL) {
  923                                 if (bpage->datavaddr != 0)
  924                                         bcopy((void *)bpage->vaddr,
  925                                               (void *)bpage->datavaddr,
  926                                               bpage->datacount);
  927                                 else
  928                                         physcopyin((void *)bpage->vaddr,
  929                                             bpage->dataaddr, bpage->datacount);
  930                                 bpage = STAILQ_NEXT(bpage, links);
  931                         }
  932                         dmat->bounce_zone->total_bounced++;
  933                 }
  934         }
  935 
  936         powerpc_sync();
  937 }
  938 
  939 static void
  940 init_bounce_pages(void *dummy __unused)
  941 {
  942 
  943         total_bpages = 0;
  944         STAILQ_INIT(&bounce_zone_list);
  945         STAILQ_INIT(&bounce_map_waitinglist);
  946         STAILQ_INIT(&bounce_map_callbacklist);
  947         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
  948 }
  949 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
  950 
  951 static struct sysctl_ctx_list *
  952 busdma_sysctl_tree(struct bounce_zone *bz)
  953 {
  954         return (&bz->sysctl_tree);
  955 }
  956 
  957 static struct sysctl_oid *
  958 busdma_sysctl_tree_top(struct bounce_zone *bz)
  959 {
  960         return (bz->sysctl_tree_top);
  961 }
  962 
  963 static int
  964 alloc_bounce_zone(bus_dma_tag_t dmat)
  965 {
  966         struct bounce_zone *bz;
  967 
  968         /* Check to see if we already have a suitable zone */
  969         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
  970                 if ((dmat->alignment <= bz->alignment)
  971                  && (dmat->lowaddr >= bz->lowaddr)) {
  972                         dmat->bounce_zone = bz;
  973                         return (0);
  974                 }
  975         }
  976 
  977         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
  978             M_NOWAIT | M_ZERO)) == NULL)
  979                 return (ENOMEM);
  980 
  981         STAILQ_INIT(&bz->bounce_page_list);
  982         bz->free_bpages = 0;
  983         bz->reserved_bpages = 0;
  984         bz->active_bpages = 0;
  985         bz->lowaddr = dmat->lowaddr;
  986         bz->alignment = MAX(dmat->alignment, PAGE_SIZE);
  987         bz->map_count = 0;
  988         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
  989         busdma_zonecount++;
  990         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
  991         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
  992         dmat->bounce_zone = bz;
  993 
  994         sysctl_ctx_init(&bz->sysctl_tree);
  995         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
  996             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
  997             CTLFLAG_RD, 0, "");
  998         if (bz->sysctl_tree_top == NULL) {
  999                 sysctl_ctx_free(&bz->sysctl_tree);
 1000                 return (0);     /* XXX error code? */
 1001         }
 1002 
 1003         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1004             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1005             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
 1006             "Total bounce pages");
 1007         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1008             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1009             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
 1010             "Free bounce pages");
 1011         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1012             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1013             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
 1014             "Reserved bounce pages");
 1015         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1016             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1017             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
 1018             "Active bounce pages");
 1019         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1020             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1021             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
 1022             "Total bounce requests");
 1023         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 1024             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1025             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
 1026             "Total bounce requests that were deferred");
 1027         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
 1028             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1029             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
 1030         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
 1031             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 1032             "alignment", CTLFLAG_RD, &bz->alignment, "");
 1033 
 1034         return (0);
 1035 }
 1036 
 1037 static int
 1038 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 1039 {
 1040         struct bounce_zone *bz;
 1041         int count;
 1042 
 1043         bz = dmat->bounce_zone;
 1044         count = 0;
 1045         while (numpages > 0) {
 1046                 struct bounce_page *bpage;
 1047 
 1048                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
 1049                                                      M_NOWAIT | M_ZERO);
 1050 
 1051                 if (bpage == NULL)
 1052                         break;
 1053                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 1054                                                          M_NOWAIT, 0ul,
 1055                                                          bz->lowaddr,
 1056                                                          PAGE_SIZE,
 1057                                                          0);
 1058                 if (bpage->vaddr == 0) {
 1059                         free(bpage, M_DEVBUF);
 1060                         break;
 1061                 }
 1062                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 1063                 mtx_lock(&bounce_lock);
 1064                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
 1065                 total_bpages++;
 1066                 bz->total_bpages++;
 1067                 bz->free_bpages++;
 1068                 mtx_unlock(&bounce_lock);
 1069                 count++;
 1070                 numpages--;
 1071         }
 1072         return (count);
 1073 }
 1074 
 1075 static int
 1076 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
 1077 {
 1078         struct bounce_zone *bz;
 1079         int pages;
 1080 
 1081         mtx_assert(&bounce_lock, MA_OWNED);
 1082         bz = dmat->bounce_zone;
 1083         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
 1084         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
 1085                 return (map->pagesneeded - (map->pagesreserved + pages));
 1086         bz->free_bpages -= pages;
 1087         bz->reserved_bpages += pages;
 1088         map->pagesreserved += pages;
 1089         pages = map->pagesneeded - map->pagesreserved;
 1090 
 1091         return (pages);
 1092 }
 1093 
 1094 static bus_addr_t
 1095 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 1096                 bus_addr_t addr, bus_size_t size)
 1097 {
 1098         struct bounce_zone *bz;
 1099         struct bounce_page *bpage;
 1100 
 1101         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
 1102 
 1103         bz = dmat->bounce_zone;
 1104         if (map->pagesneeded == 0)
 1105                 panic("add_bounce_page: map doesn't need any pages");
 1106         map->pagesneeded--;
 1107 
 1108         if (map->pagesreserved == 0)
 1109                 panic("add_bounce_page: map doesn't need any pages");
 1110         map->pagesreserved--;
 1111 
 1112         mtx_lock(&bounce_lock);
 1113         bpage = STAILQ_FIRST(&bz->bounce_page_list);
 1114         if (bpage == NULL)
 1115                 panic("add_bounce_page: free page list is empty");
 1116 
 1117         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
 1118         bz->reserved_bpages--;
 1119         bz->active_bpages++;
 1120         mtx_unlock(&bounce_lock);
 1121 
 1122         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
 1123                 /* Page offset needs to be preserved. */
 1124                 bpage->vaddr |= addr & PAGE_MASK;
 1125                 bpage->busaddr |= addr & PAGE_MASK;
 1126         }
 1127         bpage->datavaddr = vaddr;
 1128         bpage->dataaddr = addr;
 1129         bpage->datacount = size;
 1130         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 1131         return (bpage->busaddr);
 1132 }
 1133 
 1134 static void
 1135 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 1136 {
 1137         struct bus_dmamap *map;
 1138         struct bounce_zone *bz;
 1139 
 1140         bz = dmat->bounce_zone;
 1141         bpage->datavaddr = 0;
 1142         bpage->datacount = 0;
 1143         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
 1144                 /*
 1145                  * Reset the bounce page to start at offset 0.  Other uses
 1146                  * of this bounce page may need to store a full page of
 1147                  * data and/or assume it starts on a page boundary.
 1148                  */
 1149                 bpage->vaddr &= ~PAGE_MASK;
 1150                 bpage->busaddr &= ~PAGE_MASK;
 1151         }
 1152 
 1153         mtx_lock(&bounce_lock);
 1154         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
 1155         bz->free_bpages++;
 1156         bz->active_bpages--;
 1157         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 1158                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
 1159                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 1160                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 1161                                            map, links);
 1162                         busdma_swi_pending = 1;
 1163                         bz->total_deferred++;
 1164                         swi_sched(vm_ih, 0);
 1165                 }
 1166         }
 1167         mtx_unlock(&bounce_lock);
 1168 }
 1169 
 1170 void
 1171 busdma_swi(void)
 1172 {
 1173         bus_dma_tag_t dmat;
 1174         struct bus_dmamap *map;
 1175 
 1176         mtx_lock(&bounce_lock);
 1177         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 1178                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 1179                 mtx_unlock(&bounce_lock);
 1180                 dmat = map->dmat;
 1181                 (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_LOCK);
 1182                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
 1183                                     map->callback, map->callback_arg,
 1184                                     BUS_DMA_WAITOK);
 1185                 (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_UNLOCK);
 1186                 mtx_lock(&bounce_lock);
 1187         }
 1188         mtx_unlock(&bounce_lock);
 1189 }
 1190 
 1191 int
 1192 bus_dma_tag_set_iommu(bus_dma_tag_t tag, struct device *iommu, void *cookie)
 1193 {
 1194         tag->iommu = iommu;
 1195         tag->iommu_cookie = cookie;
 1196 
 1197         return (0);
 1198 }
 1199 

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