The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_mbpool.c

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    1 /*-
    2  * Copyright (c) 2003
    3  *      Fraunhofer Institute for Open Communication Systems (FhG Fokus).
    4  *      All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  *
   27  * Author: Hartmut Brandt <harti@freebsd.org>
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/6.4/sys/kern/subr_mbpool.c 139804 2005-01-06 23:35:40Z imp $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/lock.h>
   35 #include <sys/mutex.h>
   36 #include <sys/kernel.h>
   37 #include <sys/systm.h>
   38 #include <sys/malloc.h>
   39 #include <sys/module.h>
   40 
   41 #include <machine/bus.h>
   42 
   43 #include <sys/mbpool.h>
   44 
   45 MODULE_VERSION(libmbpool, 1);
   46 
   47 /*
   48  * Memory is allocated as DMA-able pages. Each page is divided into a number
   49  * of equal chunks where the last 4 bytes of each chunk are occupied by
   50  * the page number and the chunk number. The caller must take these four
   51  * bytes into account when specifying the chunk size. Each page is mapped by
   52  * its own DMA map using the user specified DMA tag.
   53  *
   54  * Each chunk has a used and a card bit in the high bits of its page number.
   55  *  0    0      chunk is free and may be allocated
   56  *  1    1      chunk has been given to the interface
   57  *  0    1      chunk is traveling through the system
   58  *  1    0      illegal
   59  */
   60 struct mbtrail {
   61         uint16_t        chunk;
   62         uint16_t        page;
   63 };
   64 #define MBP_CARD        0x8000
   65 #define MBP_USED        0x4000
   66 #define MBP_PMSK        0x3fff          /* page number mask */
   67 #define MBP_CMSK        0x01ff          /* chunk number mask */
   68 
   69 struct mbfree {
   70         SLIST_ENTRY(mbfree) link;       /* link on free list */
   71 };
   72 
   73 struct mbpage {
   74         bus_dmamap_t    map;            /* map for this page */
   75         bus_addr_t      phy;            /* physical address */
   76         void            *va;            /* the memory */
   77 };
   78 
   79 struct mbpool {
   80         const char      *name;          /* a name for this pool */
   81         bus_dma_tag_t   dmat;           /* tag for mapping */
   82         u_int           max_pages;      /* maximum number of pages */
   83         size_t          page_size;      /* size of each allocation */
   84         size_t          chunk_size;     /* size of each external mbuf */
   85 
   86         struct mtx      free_lock;      /* lock of free list */
   87         SLIST_HEAD(, mbfree) free_list; /* free list */
   88         u_int           npages;         /* current number of pages */
   89         u_int           nchunks;        /* chunks per page */
   90         struct mbpage   pages[];        /* pages */
   91 };
   92 
   93 static MALLOC_DEFINE(M_MBPOOL, "mbpools", "mbuf pools");
   94 
   95 /*
   96  * Make a trail pointer from a chunk pointer
   97  */
   98 #define C2T(P, C)       ((struct mbtrail *)((char *)(C) + (P)->chunk_size - \
   99                             sizeof(struct mbtrail)))
  100 
  101 /*
  102  * Make a free chunk pointer from a chunk number
  103  */
  104 #define N2C(P, PG, C)   ((struct mbfree *)((char *)(PG)->va + \
  105                             (C) * (P)->chunk_size))
  106 
  107 /*
  108  * Make/parse handles
  109  */
  110 #define HMAKE(P, C)     ((((P) & MBP_PMSK) << 16) | ((C) << 7))
  111 #define HPAGE(H)        (((H) >> 16) & MBP_PMSK)
  112 #define HCHUNK(H)       (((H) >>  7) & MBP_CMSK)
  113 
  114 /*
  115  * initialize a pool
  116  */
  117 int
  118 mbp_create(struct mbpool **pp, const char *name, bus_dma_tag_t dmat,
  119     u_int max_pages, size_t page_size, size_t chunk_size)
  120 {
  121         u_int nchunks;
  122 
  123         if (max_pages > MBPOOL_MAX_MAXPAGES || chunk_size == 0)
  124                 return (EINVAL);
  125         nchunks = page_size / chunk_size;
  126         if (nchunks == 0 || nchunks > MBPOOL_MAX_CHUNKS)
  127                 return (EINVAL);
  128 
  129         (*pp) = malloc(sizeof(struct mbpool) +
  130             max_pages * sizeof(struct mbpage),
  131             M_MBPOOL, M_WAITOK | M_ZERO);
  132 
  133         (*pp)->name = name;
  134         (*pp)->dmat = dmat;
  135         (*pp)->max_pages = max_pages;
  136         (*pp)->page_size = page_size;
  137         (*pp)->chunk_size = chunk_size;
  138         (*pp)->nchunks = nchunks;
  139 
  140         SLIST_INIT(&(*pp)->free_list);
  141         mtx_init(&(*pp)->free_lock, name, NULL, MTX_DEF);
  142 
  143         return (0);
  144 }
  145 
  146 /*
  147  * destroy a pool
  148  */
  149 void
  150 mbp_destroy(struct mbpool *p)
  151 {
  152         u_int i;
  153         struct mbpage *pg;
  154 #ifdef DIAGNOSTIC
  155         struct mbtrail *tr;
  156         u_int b;
  157 #endif
  158 
  159         for (i = 0; i < p->npages; i++) {
  160                 pg = &p->pages[i];
  161 #ifdef DIAGNOSTIC
  162                 for (b = 0; b < p->nchunks; b++) {
  163                         tr = C2T(p, N2C(p, pg, b));
  164                         if (tr->page & MBP_CARD)
  165                                 printf("%s: (%s) buf still on card"
  166                                     " %u/%u\n", __func__, p->name, i, b);
  167                         if (tr->page & MBP_USED)
  168                                 printf("%s: (%s) sbuf still in use"
  169                                     " %u/%u\n", __func__, p->name, i, b);
  170                 }
  171 #endif
  172                 bus_dmamap_unload(p->dmat, pg->map);
  173                 bus_dmamem_free(p->dmat, pg->va, pg->map);
  174         }
  175         mtx_destroy(&p->free_lock);
  176 
  177         free(p, M_MBPOOL);
  178 }
  179 
  180 /*
  181  * Helper function when loading a one segment DMA buffer.
  182  */
  183 static void
  184 mbp_callback(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
  185 {
  186         if (error == 0)
  187                 *(bus_addr_t *)arg = segs[0].ds_addr;
  188 }
  189 
  190 /*
  191  * Allocate a new page
  192  */
  193 static void
  194 mbp_alloc_page(struct mbpool *p)
  195 {
  196         int error;
  197         struct mbpage *pg;
  198         u_int i;
  199         struct mbfree *f;
  200         struct mbtrail *t;
  201 
  202         if (p->npages == p->max_pages) {
  203 #ifdef DIAGNOSTIC
  204                 printf("%s: (%s) page limit reached %u\n", __func__,
  205                     p->name, p->max_pages);
  206 #endif
  207                 return;
  208         }
  209         pg = &p->pages[p->npages];
  210 
  211         error = bus_dmamem_alloc(p->dmat, &pg->va, BUS_DMA_NOWAIT, &pg->map);
  212         if (error != 0) {
  213                 free(pg, M_MBPOOL);
  214                 return;
  215         }
  216 
  217         error = bus_dmamap_load(p->dmat, pg->map, pg->va, p->page_size,
  218             mbp_callback, &pg->phy, 0);
  219         if (error != 0) {
  220                 bus_dmamem_free(p->dmat, pg->va, pg->map);
  221                 free(pg, M_MBPOOL);
  222                 return;
  223         }
  224 
  225         for (i = 0; i < p->nchunks; i++) {
  226                 f = N2C(p, pg, i);
  227                 t = C2T(p, f);
  228                 t->page = p->npages;
  229                 t->chunk = i;
  230                 SLIST_INSERT_HEAD(&p->free_list, f, link);
  231         }
  232 
  233         p->npages++;
  234 }
  235 
  236 /*
  237  * allocate a chunk
  238  */
  239 void *
  240 mbp_alloc(struct mbpool *p, bus_addr_t *pap, uint32_t *hp)
  241 {
  242         struct mbfree *cf;
  243         struct mbtrail *t;
  244 
  245         mtx_lock(&p->free_lock);
  246         if ((cf = SLIST_FIRST(&p->free_list)) == NULL) {
  247                 mbp_alloc_page(p);
  248                 cf = SLIST_FIRST(&p->free_list);
  249         }
  250         if (cf == NULL) {
  251                 mtx_unlock(&p->free_lock);
  252                 return (NULL);
  253         }
  254         SLIST_REMOVE_HEAD(&p->free_list, link);
  255         mtx_unlock(&p->free_lock);
  256 
  257         t = C2T(p, cf);
  258 
  259         *pap = p->pages[t->page].phy + t->chunk * p->chunk_size;
  260         *hp = HMAKE(t->page, t->chunk);
  261 
  262         t->page |= MBP_CARD | MBP_USED;
  263 
  264         return (cf);
  265 }
  266 
  267 /*
  268  * Free a chunk
  269  */
  270 void
  271 mbp_free(struct mbpool *p, void *ptr)
  272 {
  273         struct mbtrail *t;
  274 
  275         mtx_lock(&p->free_lock);
  276         t = C2T(p, ptr);
  277         t->page &= ~(MBP_USED | MBP_CARD);
  278         SLIST_INSERT_HEAD(&p->free_list, (struct mbfree *)ptr, link);
  279         mtx_unlock(&p->free_lock);
  280 }
  281 
  282 /*
  283  * Mbuf system external mbuf free routine
  284  */
  285 void
  286 mbp_ext_free(void *buf, void *arg)
  287 {
  288         mbp_free(arg, buf);
  289 }
  290 
  291 /*
  292  * Free all buffers that are marked as beeing on the card
  293  */
  294 void
  295 mbp_card_free(struct mbpool *p)
  296 {
  297         u_int i, b;
  298         struct mbpage *pg;
  299         struct mbtrail *tr;
  300         struct mbfree *cf;
  301 
  302         mtx_lock(&p->free_lock);
  303         for (i = 0; i < p->npages; i++) {
  304                 pg = &p->pages[i];
  305                 for (b = 0; b < p->nchunks; b++) {
  306                         cf = N2C(p, pg, b);
  307                         tr = C2T(p, cf);
  308                         if (tr->page & MBP_CARD) {
  309                                 tr->page &= MBP_PMSK;
  310                                 SLIST_INSERT_HEAD(&p->free_list, cf, link);
  311                         }
  312                 }
  313         }
  314         mtx_unlock(&p->free_lock);
  315 }
  316 
  317 /*
  318  * Count buffers
  319  */
  320 void
  321 mbp_count(struct mbpool *p, u_int *used, u_int *card, u_int *free)
  322 {
  323         u_int i, b;
  324         struct mbpage *pg;
  325         struct mbtrail *tr;
  326         struct mbfree *cf;
  327 
  328         *used = *card = *free = 0;
  329         for (i = 0; i < p->npages; i++) {
  330                 pg = &p->pages[i];
  331                 for (b = 0; b < p->nchunks; b++) {
  332                         tr = C2T(p, N2C(p, pg, b));
  333                         if (tr->page & MBP_CARD)
  334                                 (*card)++;
  335                         if (tr->page & MBP_USED)
  336                                 (*used)++;
  337                 }
  338         }
  339         mtx_lock(&p->free_lock);
  340         SLIST_FOREACH(cf, &p->free_list, link)
  341                 *free++;
  342         mtx_unlock(&p->free_lock);
  343 }
  344 
  345 /*
  346  * Get the buffer from a handle and clear the card flag.
  347  */
  348 void *
  349 mbp_get(struct mbpool *p, uint32_t h)
  350 {
  351         struct mbfree *cf;
  352         struct mbtrail *tr;
  353 
  354         cf = N2C(p, &p->pages[HPAGE(h)], HCHUNK(h));
  355         tr = C2T(p, cf);
  356 
  357 #ifdef DIAGNOSTIC
  358         if (!(tr->page & MBP_CARD))
  359                 printf("%s: (%s) chunk %u page %u not on card\n", __func__,
  360                     p->name, HCHUNK(h), HPAGE(h));
  361 #endif
  362 
  363         tr->page &= ~MBP_CARD;
  364         return (cf);
  365 }
  366 
  367 /*
  368  * Get the buffer from a handle and keep the card flag.
  369  */
  370 void *
  371 mbp_get_keep(struct mbpool *p, uint32_t h)
  372 {
  373         struct mbfree *cf;
  374         struct mbtrail *tr;
  375 
  376         cf = N2C(p, &p->pages[HPAGE(h)], HCHUNK(h));
  377         tr = C2T(p, cf);
  378 
  379 #ifdef DIAGNOSTIC
  380         if (!(tr->page & MBP_CARD))
  381                 printf("%s: (%s) chunk %u page %u not on card\n", __func__,
  382                     p->name, HCHUNK(h), HPAGE(h));
  383 #endif
  384 
  385         return (cf);
  386 }
  387 
  388 /*
  389  * sync the chunk
  390  */
  391 void
  392 mbp_sync(struct mbpool *p, uint32_t h, bus_addr_t off, bus_size_t len, u_int op)
  393 {
  394 
  395 #if 0
  396         bus_dmamap_sync_size(p->dmat, p->pages[HPAGE(h)].map,
  397             HCHUNK(h) * p->chunk_size + off, len, op);
  398 #endif
  399 }

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