The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/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  * $FreeBSD: releng/5.1/sys/amd64/amd64/busdma_machdep.c 115343 2003-05-27 04:59:59Z scottl $
   27  */
   28 
   29 #include <sys/param.h>
   30 #include <sys/systm.h>
   31 #include <sys/malloc.h>
   32 #include <sys/bus.h>
   33 #include <sys/interrupt.h>
   34 #include <sys/kernel.h>
   35 #include <sys/lock.h>
   36 #include <sys/proc.h>
   37 #include <sys/mutex.h>
   38 #include <sys/mbuf.h>
   39 #include <sys/uio.h>
   40 
   41 #include <vm/vm.h>
   42 #include <vm/vm_page.h>
   43 #include <vm/vm_map.h>
   44 
   45 #include <machine/atomic.h>
   46 #include <machine/bus.h>
   47 #include <machine/md_var.h>
   48 
   49 #define MAX_BPAGES 512
   50 
   51 struct bus_dma_tag {
   52         bus_dma_tag_t     parent;
   53         bus_size_t        alignment;
   54         bus_size_t        boundary;
   55         bus_addr_t        lowaddr;
   56         bus_addr_t        highaddr;
   57         bus_dma_filter_t *filter;
   58         void             *filterarg;
   59         bus_size_t        maxsize;
   60         u_int             nsegments;
   61         bus_size_t        maxsegsz;
   62         int               flags;
   63         int               ref_count;
   64         int               map_count;
   65 };
   66 
   67 struct bounce_page {
   68         vm_offset_t     vaddr;          /* kva of bounce buffer */
   69         bus_addr_t      busaddr;        /* Physical address */
   70         vm_offset_t     datavaddr;      /* kva of client data */
   71         bus_size_t      datacount;      /* client data count */
   72         STAILQ_ENTRY(bounce_page) links;
   73 };
   74 
   75 int busdma_swi_pending;
   76 
   77 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
   78 static int free_bpages;
   79 static int reserved_bpages;
   80 static int active_bpages;
   81 static int total_bpages;
   82 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
   83 
   84 struct bus_dmamap {
   85         struct bp_list         bpages;
   86         int                    pagesneeded;
   87         int                    pagesreserved;
   88         bus_dma_tag_t          dmat;
   89         void                  *buf;             /* unmapped buffer pointer */
   90         bus_size_t             buflen;          /* unmapped buffer length */
   91         bus_dmamap_callback_t *callback;
   92         void                  *callback_arg;
   93         STAILQ_ENTRY(bus_dmamap) links;
   94 };
   95 
   96 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
   97 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
   98 static struct bus_dmamap nobounce_dmamap;
   99 
  100 static void init_bounce_pages(void *dummy);
  101 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
  102 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
  103                                 int commit);
  104 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
  105                                    vm_offset_t vaddr, bus_size_t size);
  106 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
  107 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
  108 
  109 /* To protect all the the bounce pages related lists and data. */
  110 static struct mtx bounce_lock;
  111 
  112 /*
  113  * Return true if a match is made.
  114  * 
  115  * To find a match walk the chain of bus_dma_tag_t's looking for 'paddr'.
  116  * 
  117  * If paddr is within the bounds of the dma tag then call the filter callback
  118  * to check for a match, if there is no filter callback then assume a match.
  119  */
  120 static __inline int
  121 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
  122 {
  123         int retval;
  124 
  125         retval = 0;
  126         do {
  127                 if (paddr > dmat->lowaddr
  128                  && paddr <= dmat->highaddr
  129                  && (dmat->filter == NULL
  130                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
  131                         retval = 1;
  132 
  133                 dmat = dmat->parent;            
  134         } while (retval == 0 && dmat != NULL);
  135         return (retval);
  136 }
  137 
  138 #define BUS_DMA_MIN_ALLOC_COMP BUS_DMA_BUS4
  139 /*
  140  * Allocate a device specific dma_tag.
  141  */
  142 int
  143 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
  144                    bus_size_t boundary, bus_addr_t lowaddr,
  145                    bus_addr_t highaddr, bus_dma_filter_t *filter,
  146                    void *filterarg, bus_size_t maxsize, int nsegments,
  147                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
  148 {
  149         bus_dma_tag_t newtag;
  150         int error = 0;
  151 
  152         /* Return a NULL tag on failure */
  153         *dmat = NULL;
  154 
  155         newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF, M_NOWAIT);
  156         if (newtag == NULL)
  157                 return (ENOMEM);
  158 
  159         newtag->parent = parent;
  160         newtag->alignment = alignment;
  161         newtag->boundary = boundary;
  162         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
  163         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) +
  164             (PAGE_SIZE - 1);
  165         newtag->filter = filter;
  166         newtag->filterarg = filterarg;
  167         newtag->maxsize = maxsize;
  168         newtag->nsegments = nsegments;
  169         newtag->maxsegsz = maxsegsz;
  170         newtag->flags = flags;
  171         newtag->ref_count = 1; /* Count ourself */
  172         newtag->map_count = 0;
  173         
  174         /* Take into account any restrictions imposed by our parent tag */
  175         if (parent != NULL) {
  176                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
  177                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
  178                 /*
  179                  * XXX Not really correct??? Probably need to honor boundary
  180                  *     all the way up the inheritence chain.
  181                  */
  182                 newtag->boundary = MAX(parent->boundary, newtag->boundary);
  183                 if (newtag->filter == NULL) {
  184                         /*
  185                          * Short circuit looking at our parent directly
  186                          * since we have encapsulated all of its information
  187                          */
  188                         newtag->filter = parent->filter;
  189                         newtag->filterarg = parent->filterarg;
  190                         newtag->parent = parent->parent;
  191                 }
  192                 if (newtag->parent != NULL)
  193                         atomic_add_int(&parent->ref_count, 1);
  194         }
  195         
  196         if (newtag->lowaddr < ptoa((vm_paddr_t)Maxmem) &&
  197             (flags & BUS_DMA_ALLOCNOW) != 0) {
  198                 /* Must bounce */
  199 
  200                 if (lowaddr > bounce_lowaddr) {
  201                         /*
  202                          * Go through the pool and kill any pages
  203                          * that don't reside below lowaddr.
  204                          */
  205                         panic("bus_dma_tag_create: page reallocation "
  206                               "not implemented");
  207                 }
  208                 if (ptoa(total_bpages) < maxsize) {
  209                         int pages;
  210 
  211                         pages = atop(maxsize) - total_bpages;
  212 
  213                         /* Add pages to our bounce pool */
  214                         if (alloc_bounce_pages(newtag, pages) < pages)
  215                                 error = ENOMEM;
  216                 }
  217                 /* Performed initial allocation */
  218                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
  219         }
  220         
  221         if (error != 0) {
  222                 free(newtag, M_DEVBUF);
  223         } else {
  224                 *dmat = newtag;
  225         }
  226         return (error);
  227 }
  228 
  229 int
  230 bus_dma_tag_destroy(bus_dma_tag_t dmat)
  231 {
  232         if (dmat != NULL) {
  233 
  234                 if (dmat->map_count != 0)
  235                         return (EBUSY);
  236 
  237                 while (dmat != NULL) {
  238                         bus_dma_tag_t parent;
  239 
  240                         parent = dmat->parent;
  241                         atomic_subtract_int(&dmat->ref_count, 1);
  242                         if (dmat->ref_count == 0) {
  243                                 free(dmat, M_DEVBUF);
  244                                 /*
  245                                  * Last reference count, so
  246                                  * release our reference
  247                                  * count on our parent.
  248                                  */
  249                                 dmat = parent;
  250                         } else
  251                                 dmat = NULL;
  252                 }
  253         }
  254         return (0);
  255 }
  256 
  257 /*
  258  * Allocate a handle for mapping from kva/uva/physical
  259  * address space into bus device space.
  260  */
  261 int
  262 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
  263 {
  264         int error;
  265 
  266         error = 0;
  267 
  268         if (dmat->lowaddr < ptoa((vm_paddr_t)Maxmem)) {
  269                 /* Must bounce */
  270                 int maxpages;
  271 
  272                 *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
  273                                              M_NOWAIT | M_ZERO);
  274                 if (*mapp == NULL)
  275                         return (ENOMEM);
  276 
  277                 /* Initialize the new map */
  278                 STAILQ_INIT(&((*mapp)->bpages));
  279 
  280                 /*
  281                  * Attempt to add pages to our pool on a per-instance
  282                  * basis up to a sane limit.
  283                  */
  284                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
  285                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
  286                  || (dmat->map_count > 0
  287                   && total_bpages < maxpages)) {
  288                         int pages;
  289 
  290                         if (dmat->lowaddr > bounce_lowaddr) {
  291                                 /*
  292                                  * Go through the pool and kill any pages
  293                                  * that don't reside below lowaddr.
  294                                  */
  295                                 panic("bus_dmamap_create: page reallocation "
  296                                       "not implemented");
  297                         }
  298                         pages = MAX(atop(dmat->maxsize), 1);
  299                         pages = MIN(maxpages - total_bpages, pages);
  300                         if (alloc_bounce_pages(dmat, pages) < pages)
  301                                 error = ENOMEM;
  302 
  303                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
  304                                 if (error == 0)
  305                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
  306                         } else {
  307                                 error = 0;
  308                         }
  309                 }
  310         } else {
  311                 *mapp = NULL;
  312         }
  313         if (error == 0)
  314                 dmat->map_count++;
  315         return (error);
  316 }
  317 
  318 /*
  319  * Destroy a handle for mapping from kva/uva/physical
  320  * address space into bus device space.
  321  */
  322 int
  323 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
  324 {
  325         if (map != NULL) {
  326                 if (STAILQ_FIRST(&map->bpages) != NULL)
  327                         return (EBUSY);
  328                 free(map, M_DEVBUF);
  329         }
  330         dmat->map_count--;
  331         return (0);
  332 }
  333 
  334 
  335 /*
  336  * Allocate a piece of memory that can be efficiently mapped into
  337  * bus device space based on the constraints lited in the dma tag.
  338  * A dmamap to for use with dmamap_load is also allocated.
  339  */
  340 int
  341 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  342                  bus_dmamap_t *mapp)
  343 {
  344         /* If we succeed, no mapping/bouncing will be required */
  345         *mapp = NULL;
  346 
  347         if ((dmat->maxsize <= PAGE_SIZE) &&
  348             dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
  349                 *vaddr = malloc(dmat->maxsize, M_DEVBUF,
  350                                 (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK);
  351         } else {
  352                 /*
  353                  * XXX Use Contigmalloc until it is merged into this facility
  354                  *     and handles multi-seg allocations.  Nobody is doing
  355                  *     multi-seg allocations yet though.
  356                  */
  357                 mtx_lock(&Giant);
  358                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
  359                     (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK,
  360                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
  361                     dmat->boundary);
  362                 mtx_unlock(&Giant);
  363         }
  364         if (*vaddr == NULL)
  365                 return (ENOMEM);
  366         return (0);
  367 }
  368 
  369 /*
  370  * Free a piece of memory and it's allociated dmamap, that was allocated
  371  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
  372  */
  373 void
  374 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
  375 {
  376         /*
  377          * dmamem does not need to be bounced, so the map should be
  378          * NULL
  379          */
  380         if (map != NULL)
  381                 panic("bus_dmamem_free: Invalid map freed\n");
  382         if ((dmat->maxsize <= PAGE_SIZE)
  383          && dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
  384                 free(vaddr, M_DEVBUF);
  385         else {
  386                 mtx_lock(&Giant);
  387                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
  388                 mtx_unlock(&Giant);
  389         }
  390 }
  391 
  392 /*
  393  * Utility function to load a linear buffer.  lastaddrp holds state
  394  * between invocations (for multiple-buffer loads).  segp contains
  395  * the starting segment on entrace, and the ending segment on exit.
  396  * first indicates if this is the first invocation of this function.
  397  */
  398 static int
  399 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
  400                         bus_dmamap_t map,
  401                         bus_dma_segment_t segs[],
  402                         void *buf, bus_size_t buflen,
  403                         struct thread *td,
  404                         int flags,
  405                         bus_addr_t *lastaddrp,
  406                         int *segp,
  407                         int first)
  408 {
  409         bus_size_t sgsize;
  410         bus_addr_t curaddr, lastaddr, baddr, bmask;
  411         vm_offset_t vaddr;
  412         bus_addr_t paddr;
  413         int needbounce = 0;
  414         int seg;
  415         pmap_t pmap;
  416 
  417         if (map == NULL)
  418                 map = &nobounce_dmamap;
  419 
  420         if (td != NULL)
  421                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
  422         else
  423                 pmap = NULL;
  424 
  425         if (dmat->lowaddr < ptoa((vm_paddr_t)Maxmem)) {
  426                 vm_offset_t     vendaddr;
  427 
  428                 /*
  429                  * Count the number of bounce pages
  430                  * needed in order to complete this transfer
  431                  */
  432                 vaddr = trunc_page((vm_offset_t)buf);
  433                 vendaddr = (vm_offset_t)buf + buflen;
  434 
  435                 while (vaddr < vendaddr) {
  436                         paddr = pmap_kextract(vaddr);
  437                         if (run_filter(dmat, paddr) != 0) {
  438                                 needbounce = 1;
  439                                 map->pagesneeded++;
  440                         }
  441                         vaddr += PAGE_SIZE;
  442                 }
  443         }
  444 
  445         vaddr = (vm_offset_t)buf;
  446 
  447         /* Reserve Necessary Bounce Pages */
  448         if (map->pagesneeded != 0) {
  449                 mtx_lock(&bounce_lock);
  450                 if (flags & BUS_DMA_NOWAIT) {
  451                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
  452                                 mtx_unlock(&bounce_lock);
  453                                 return (ENOMEM);
  454                         }
  455                 } else {
  456                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
  457                                 /* Queue us for resources */
  458                                 map->dmat = dmat;
  459                                 map->buf = buf;
  460                                 map->buflen = buflen;
  461                                 STAILQ_INSERT_TAIL(&bounce_map_waitinglist,
  462                                                                 map, links);
  463                                 mtx_unlock(&bounce_lock);
  464                                 return (EINPROGRESS);
  465                         }
  466                 }
  467                 mtx_unlock(&bounce_lock);
  468         }
  469 
  470         lastaddr = *lastaddrp;
  471         bmask = ~(dmat->boundary - 1);
  472 
  473         for (seg = *segp; buflen > 0 ; ) {
  474                 /*
  475                  * Get the physical address for this segment.
  476                  */
  477                 if (pmap)
  478                         curaddr = pmap_extract(pmap, vaddr);
  479                 else
  480                         curaddr = pmap_kextract(vaddr);
  481 
  482                 /*
  483                  * Compute the segment size, and adjust counts.
  484                  */
  485                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
  486                 if (buflen < sgsize)
  487                         sgsize = buflen;
  488 
  489                 /*
  490                  * Make sure we don't cross any boundaries.
  491                  */
  492                 if (dmat->boundary > 0) {
  493                         baddr = (curaddr + dmat->boundary) & bmask;
  494                         if (sgsize > (baddr - curaddr))
  495                                 sgsize = (baddr - curaddr);
  496                 }
  497 
  498                 if (map->pagesneeded != 0 && run_filter(dmat, curaddr))
  499                         curaddr = add_bounce_page(dmat, map, vaddr, sgsize);
  500 
  501                 /*
  502                  * Insert chunk into a segment, coalescing with
  503                  * previous segment if possible.
  504                  */
  505                 if (first) {
  506                         segs[seg].ds_addr = curaddr;
  507                         segs[seg].ds_len = sgsize;
  508                         first = 0;
  509                 } else {
  510                         if (needbounce == 0 && curaddr == lastaddr &&
  511                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
  512                             (dmat->boundary == 0 ||
  513                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
  514                                 segs[seg].ds_len += sgsize;
  515                         else {
  516                                 if (++seg >= dmat->nsegments)
  517                                         break;
  518                                 segs[seg].ds_addr = curaddr;
  519                                 segs[seg].ds_len = sgsize;
  520                         }
  521                 }
  522 
  523                 lastaddr = curaddr + sgsize;
  524                 vaddr += sgsize;
  525                 buflen -= sgsize;
  526         }
  527 
  528         *segp = seg;
  529         *lastaddrp = lastaddr;
  530 
  531         /*
  532          * Did we fit?
  533          */
  534         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
  535 }
  536 
  537 #define BUS_DMAMAP_NSEGS ((64 * 1024) / PAGE_SIZE + 1)
  538 
  539 /*
  540  * Map the buffer buf into bus space using the dmamap map.
  541  */
  542 int
  543 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
  544                 bus_size_t buflen, bus_dmamap_callback_t *callback,
  545                 void *callback_arg, int flags)
  546 {
  547 #ifdef __GNUC__
  548         bus_dma_segment_t       dm_segments[dmat->nsegments];
  549 #else
  550         bus_dma_segment_t       dm_segments[BUS_DMAMAP_NSEGS];
  551 #endif
  552         bus_addr_t              lastaddr = 0;
  553         int                     error, nsegs = 0;
  554 
  555         if (map != NULL) {
  556                 flags |= BUS_DMA_WAITOK;
  557                 map->callback = callback;
  558                 map->callback_arg = callback_arg;
  559         }
  560 
  561         error = _bus_dmamap_load_buffer(dmat, map, dm_segments, buf, buflen,
  562             NULL, flags, &lastaddr, &nsegs, 1);
  563 
  564         if (error == EINPROGRESS)
  565                 return (error);
  566 
  567         if (error)
  568                 (*callback)(callback_arg, dm_segments, 0, error);
  569         else
  570                 (*callback)(callback_arg, dm_segments, nsegs + 1, 0);
  571 
  572         return (0);
  573 }
  574 
  575 
  576 /*
  577  * Like _bus_dmamap_load(), but for mbufs.
  578  */
  579 int
  580 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
  581                      struct mbuf *m0,
  582                      bus_dmamap_callback2_t *callback, void *callback_arg,
  583                      int flags)
  584 {
  585 #ifdef __GNUC__
  586         bus_dma_segment_t dm_segments[dmat->nsegments];
  587 #else
  588         bus_dma_segment_t dm_segments[BUS_DMAMAP_NSEGS];
  589 #endif
  590         int nsegs, error;
  591 
  592         KASSERT(m0->m_flags & M_PKTHDR,
  593                 ("bus_dmamap_load_mbuf: no packet header"));
  594 
  595         flags |= BUS_DMA_NOWAIT;
  596         nsegs = 0;
  597         error = 0;
  598         if (m0->m_pkthdr.len <= dmat->maxsize) {
  599                 int first = 1;
  600                 bus_addr_t lastaddr = 0;
  601                 struct mbuf *m;
  602 
  603                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
  604                         if (m->m_len > 0) {
  605                                 error = _bus_dmamap_load_buffer(dmat, map,
  606                                                 dm_segments,
  607                                                 m->m_data, m->m_len,
  608                                                 NULL, flags, &lastaddr,
  609                                                 &nsegs, first);
  610                                 first = 0;
  611                         }
  612                 }
  613         } else {
  614                 error = EINVAL;
  615         }
  616 
  617         if (error) {
  618                 /* force "no valid mappings" in callback */
  619                 (*callback)(callback_arg, dm_segments, 0, 0, error);
  620         } else {
  621                 (*callback)(callback_arg, dm_segments,
  622                             nsegs+1, m0->m_pkthdr.len, error);
  623         }
  624         return (error);
  625 }
  626 
  627 /*
  628  * Like _bus_dmamap_load(), but for uios.
  629  */
  630 int
  631 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
  632                     struct uio *uio,
  633                     bus_dmamap_callback2_t *callback, void *callback_arg,
  634                     int flags)
  635 {
  636         bus_addr_t lastaddr;
  637 #ifdef __GNUC__
  638         bus_dma_segment_t dm_segments[dmat->nsegments];
  639 #else
  640         bus_dma_segment_t dm_segments[BUS_DMAMAP_NSEGS];
  641 #endif
  642         int nsegs, error, first, i;
  643         bus_size_t resid;
  644         struct iovec *iov;
  645         struct thread *td = NULL;
  646 
  647         flags |= BUS_DMA_NOWAIT;
  648         resid = uio->uio_resid;
  649         iov = uio->uio_iov;
  650 
  651         if (uio->uio_segflg == UIO_USERSPACE) {
  652                 td = uio->uio_td;
  653                 KASSERT(td != NULL,
  654                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
  655         }
  656 
  657         nsegs = 0;
  658         error = 0;
  659         first = 1;
  660         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
  661                 /*
  662                  * Now at the first iovec to load.  Load each iovec
  663                  * until we have exhausted the residual count.
  664                  */
  665                 bus_size_t minlen =
  666                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
  667                 caddr_t addr = (caddr_t) iov[i].iov_base;
  668 
  669                 if (minlen > 0) {
  670                         error = _bus_dmamap_load_buffer(dmat, map,
  671                                         dm_segments,
  672                                         addr, minlen,
  673                                         td, flags, &lastaddr, &nsegs, first);
  674                         first = 0;
  675 
  676                         resid -= minlen;
  677                 }
  678         }
  679 
  680         if (error) {
  681                 /* force "no valid mappings" in callback */
  682                 (*callback)(callback_arg, dm_segments, 0, 0, error);
  683         } else {
  684                 (*callback)(callback_arg, dm_segments,
  685                             nsegs+1, uio->uio_resid, error);
  686         }
  687         return (error);
  688 }
  689 
  690 /*
  691  * Release the mapping held by map.
  692  */
  693 void
  694 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
  695 {
  696         struct bounce_page *bpage;
  697 
  698         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
  699                 STAILQ_REMOVE_HEAD(&map->bpages, links);
  700                 free_bounce_page(dmat, bpage);
  701         }
  702 }
  703 
  704 void
  705 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
  706 {
  707         struct bounce_page *bpage;
  708 
  709         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
  710                 /*
  711                  * Handle data bouncing.  We might also
  712                  * want to add support for invalidating
  713                  * the caches on broken hardware
  714                  */
  715                 if (op & BUS_DMASYNC_PREWRITE) {
  716                         while (bpage != NULL) {
  717                                 bcopy((void *)bpage->datavaddr,
  718                                       (void *)bpage->vaddr,
  719                                       bpage->datacount);
  720                                 bpage = STAILQ_NEXT(bpage, links);
  721                         }
  722                 }
  723 
  724                 if (op & BUS_DMASYNC_POSTREAD) {
  725                         while (bpage != NULL) {
  726                                 bcopy((void *)bpage->vaddr,
  727                                       (void *)bpage->datavaddr,
  728                                       bpage->datacount);
  729                                 bpage = STAILQ_NEXT(bpage, links);
  730                         }
  731                 }
  732         }
  733 }
  734 
  735 static void
  736 init_bounce_pages(void *dummy __unused)
  737 {
  738 
  739         free_bpages = 0;
  740         reserved_bpages = 0;
  741         active_bpages = 0;
  742         total_bpages = 0;
  743         STAILQ_INIT(&bounce_page_list);
  744         STAILQ_INIT(&bounce_map_waitinglist);
  745         STAILQ_INIT(&bounce_map_callbacklist);
  746         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
  747 }
  748 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
  749 
  750 static int
  751 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
  752 {
  753         int count;
  754 
  755         count = 0;
  756         while (numpages > 0) {
  757                 struct bounce_page *bpage;
  758 
  759                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
  760                                                      M_NOWAIT | M_ZERO);
  761 
  762                 if (bpage == NULL)
  763                         break;
  764                 mtx_lock(&Giant);
  765                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
  766                                                          M_NOWAIT, 0ul,
  767                                                          dmat->lowaddr,
  768                                                          PAGE_SIZE,
  769                                                          0);
  770                 mtx_unlock(&Giant);
  771                 if (bpage->vaddr == 0) {
  772                         free(bpage, M_DEVBUF);
  773                         break;
  774                 }
  775                 bpage->busaddr = pmap_kextract(bpage->vaddr);
  776                 mtx_lock(&bounce_lock);
  777                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
  778                 total_bpages++;
  779                 free_bpages++;
  780                 mtx_unlock(&bounce_lock);
  781                 count++;
  782                 numpages--;
  783         }
  784         return (count);
  785 }
  786 
  787 static int
  788 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
  789 {
  790         int pages;
  791 
  792         mtx_assert(&bounce_lock, MA_OWNED);
  793         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
  794         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
  795                 return (map->pagesneeded - (map->pagesreserved + pages));
  796         free_bpages -= pages;
  797         reserved_bpages += pages;
  798         map->pagesreserved += pages;
  799         pages = map->pagesneeded - map->pagesreserved;
  800 
  801         return (pages);
  802 }
  803 
  804 static bus_addr_t
  805 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
  806                 bus_size_t size)
  807 {
  808         struct bounce_page *bpage;
  809 
  810         KASSERT(map != NULL && map != &nobounce_dmamap,
  811             ("add_bounce_page: bad map %p", map));
  812 
  813         if (map->pagesneeded == 0)
  814                 panic("add_bounce_page: map doesn't need any pages");
  815         map->pagesneeded--;
  816 
  817         if (map->pagesreserved == 0)
  818                 panic("add_bounce_page: map doesn't need any pages");
  819         map->pagesreserved--;
  820 
  821         mtx_lock(&bounce_lock);
  822         bpage = STAILQ_FIRST(&bounce_page_list);
  823         if (bpage == NULL)
  824                 panic("add_bounce_page: free page list is empty");
  825 
  826         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
  827         reserved_bpages--;
  828         active_bpages++;
  829         mtx_unlock(&bounce_lock);
  830 
  831         bpage->datavaddr = vaddr;
  832         bpage->datacount = size;
  833         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
  834         return (bpage->busaddr);
  835 }
  836 
  837 static void
  838 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
  839 {
  840         struct bus_dmamap *map;
  841 
  842         bpage->datavaddr = 0;
  843         bpage->datacount = 0;
  844 
  845         mtx_lock(&bounce_lock);
  846         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
  847         free_bpages++;
  848         active_bpages--;
  849         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
  850                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
  851                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
  852                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
  853                                            map, links);
  854                         busdma_swi_pending = 1;
  855                         swi_sched(vm_ih, 0);
  856                 }
  857         }
  858         mtx_unlock(&bounce_lock);
  859 }
  860 
  861 void
  862 busdma_swi(void)
  863 {
  864         struct bus_dmamap *map;
  865 
  866         mtx_lock(&bounce_lock);
  867         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
  868                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
  869                 mtx_unlock(&bounce_lock);
  870                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
  871                                 map->callback, map->callback_arg, /*flags*/0);
  872                 mtx_lock(&bounce_lock);
  873         }
  874         mtx_unlock(&bounce_lock);
  875 }

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