freebsd-skq/sys/kern/subr_mbpool.c
Hartmut Brandt 7e9024cdd9 Add a facility for devices, specifically network interfaces, that require
large to huge amounts of small or medium sized receive buffers. The problem
with these situations is that they eat up the available DMA address space
very quickly when using mbufs or even mbuf clusters. Additionally this
facility provides a direct mapping between 32-bit integers and these buffers.
This is needed for devices originally designed for 32-bit systems. Ususally
the virtual address of the buffer is used as a handle to find the buffer as
soon as it is returned by the card. This does not work for 64-bit machines
and hence this mapping is needed.
2003-07-15 08:59:38 +00:00

400 lines
9.0 KiB
C

/*
* Copyright (c) 2003
* Fraunhofer Institute for Open Communication Systems (FhG Fokus).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Author: Hartmut Brandt <harti@freebsd.org>
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <machine/bus.h>
#include <sys/mbpool.h>
MODULE_VERSION(libmbpool, 1);
/*
* Memory is allocated as DMA-able pages. Each page is divided into a number
* of equal chunks where the last 4 bytes of each chunk are occupied by
* the page number and the chunk number. The caller must take these four
* bytes into account when specifying the chunk size. Each page is mapped by
* its own DMA map using the user specified DMA tag.
*
* Each chunk has a used and a card bit in the high bits of its page number.
* 0 0 chunk is free and may be allocated
* 1 1 chunk has been given to the interface
* 0 1 chunk is traveling through the system
* 1 0 illegal
*/
struct mbtrail {
uint16_t chunk;
uint16_t page;
};
#define MBP_CARD 0x8000
#define MBP_USED 0x4000
#define MBP_PMSK 0x3fff /* page number mask */
#define MBP_CMSK 0x01ff /* chunk number mask */
struct mbfree {
SLIST_ENTRY(mbfree) link; /* link on free list */
};
struct mbpage {
bus_dmamap_t map; /* map for this page */
bus_addr_t phy; /* physical address */
void *va; /* the memory */
};
struct mbpool {
const char *name; /* a name for this pool */
bus_dma_tag_t dmat; /* tag for mapping */
u_int max_pages; /* maximum number of pages */
size_t page_size; /* size of each allocation */
size_t chunk_size; /* size of each external mbuf */
struct mtx free_lock; /* lock of free list */
SLIST_HEAD(, mbfree) free_list; /* free list */
u_int npages; /* current number of pages */
u_int nchunks; /* chunks per page */
struct mbpage pages[]; /* pages */
};
static MALLOC_DEFINE(M_MBPOOL, "mbpools", "mbuf pools");
/*
* Make a trail pointer from a chunk pointer
*/
#define C2T(P, C) ((struct mbtrail *)((char *)(C) + (P)->chunk_size - \
sizeof(struct mbtrail)))
/*
* Make a free chunk pointer from a chunk number
*/
#define N2C(P, PG, C) ((struct mbfree *)((char *)(PG)->va + \
(C) * (P)->chunk_size))
/*
* Make/parse handles
*/
#define HMAKE(P, C) ((((P) & MBP_PMSK) << 16) | ((C) << 7))
#define HPAGE(H) (((H) >> 16) & MBP_PMSK)
#define HCHUNK(H) (((H) >> 7) & MBP_CMSK)
/*
* initialize a pool
*/
int
mbp_create(struct mbpool **pp, const char *name, bus_dma_tag_t dmat,
u_int max_pages, size_t page_size, size_t chunk_size)
{
u_int nchunks;
if (max_pages > MBPOOL_MAX_MAXPAGES || chunk_size == 0)
return (EINVAL);
nchunks = page_size / chunk_size;
if (nchunks == 0 || nchunks > MBPOOL_MAX_CHUNKS)
return (EINVAL);
(*pp) = malloc(sizeof(struct mbpool) +
max_pages * sizeof(struct mbpage),
M_MBPOOL, M_WAITOK | M_ZERO);
(*pp)->name = name;
(*pp)->dmat = dmat;
(*pp)->max_pages = max_pages;
(*pp)->page_size = page_size;
(*pp)->chunk_size = chunk_size;
(*pp)->nchunks = nchunks;
SLIST_INIT(&(*pp)->free_list);
mtx_init(&(*pp)->free_lock, name, NULL, 0);
return (0);
}
/*
* destroy a pool
*/
void
mbp_destroy(struct mbpool *p)
{
u_int i;
struct mbpage *pg;
#ifdef DIAGNOSTIC
struct mbtrail *tr;
u_int b;
#endif
for (i = 0; i < p->npages; i++) {
pg = &p->pages[i];
#ifdef DIAGNOSTIC
for (b = 0; b < p->nchunks; b++) {
tr = C2T(p, N2C(p, pg, b));
if (tr->page & MBP_CARD)
printf("%s: (%s) buf still on card"
" %u/%u\n", __func__, p->name, i, b);
if (tr->page & MBP_USED)
printf("%s: (%s) sbuf still in use"
" %u/%u\n", __func__, p->name, i, b);
}
#endif
bus_dmamap_unload(p->dmat, pg->map);
bus_dmamem_free(p->dmat, pg->va, pg->map);
}
mtx_destroy(&p->free_lock);
free(p, M_MBPOOL);
}
/*
* Helper function when loading a one segment DMA buffer.
*/
static void
mbp_callback(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
if (error == 0)
*(bus_addr_t *)arg = segs[0].ds_addr;
}
/*
* Allocate a new page
*/
static void
mbp_alloc_page(struct mbpool *p)
{
int error;
struct mbpage *pg;
u_int i;
struct mbfree *f;
struct mbtrail *t;
if (p->npages == p->max_pages) {
#ifdef DIAGNOSTIC
printf("%s: (%s) page limit reached %u\n", __func__,
p->name, p->max_pages);
#endif
return;
}
pg = &p->pages[p->npages];
error = bus_dmamem_alloc(p->dmat, &pg->va, BUS_DMA_NOWAIT, &pg->map);
if (error != 0) {
free(pg, M_MBPOOL);
return;
}
error = bus_dmamap_load(p->dmat, pg->map, pg->va, p->page_size,
mbp_callback, &pg->phy, 0);
if (error != 0) {
bus_dmamem_free(p->dmat, pg->va, pg->map);
free(pg, M_MBPOOL);
return;
}
for (i = 0; i < p->nchunks; i++) {
f = N2C(p, pg, i);
t = C2T(p, f);
t->page = p->npages;
t->chunk = i;
SLIST_INSERT_HEAD(&p->free_list, f, link);
}
p->npages++;
}
/*
* allocate a chunk
*/
void *
mbp_alloc(struct mbpool *p, bus_addr_t *pap, uint32_t *hp)
{
struct mbfree *cf;
struct mbtrail *t;
mtx_lock(&p->free_lock);
if ((cf = SLIST_FIRST(&p->free_list)) == NULL) {
mbp_alloc_page(p);
cf = SLIST_FIRST(&p->free_list);
}
if (cf == NULL) {
mtx_unlock(&p->free_lock);
return (NULL);
}
SLIST_REMOVE_HEAD(&p->free_list, link);
mtx_unlock(&p->free_lock);
t = C2T(p, cf);
*pap = p->pages[t->page].phy + t->chunk * p->chunk_size;
*hp = HMAKE(t->page, t->chunk);
t->page |= MBP_CARD | MBP_USED;
return (cf);
}
/*
* Free a chunk
*/
void
mbp_free(struct mbpool *p, void *ptr)
{
struct mbtrail *t;
mtx_lock(&p->free_lock);
t = C2T(p, ptr);
t->page &= ~(MBP_USED | MBP_CARD);
SLIST_INSERT_HEAD(&p->free_list, (struct mbfree *)ptr, link);
mtx_unlock(&p->free_lock);
}
/*
* Mbuf system external mbuf free routine
*/
void
mbp_ext_free(void *buf, void *arg)
{
mbp_free(arg, buf);
}
/*
* Free all buffers that are marked as beeing on the card
*/
void
mbp_card_free(struct mbpool *p)
{
u_int i, b;
struct mbpage *pg;
struct mbtrail *tr;
struct mbfree *cf;
mtx_lock(&p->free_lock);
for (i = 0; i < p->npages; i++) {
pg = &p->pages[i];
for (b = 0; b < p->nchunks; b++) {
cf = N2C(p, pg, b);
tr = C2T(p, cf);
if (tr->page & MBP_CARD) {
tr->page &= MBP_PMSK;
SLIST_INSERT_HEAD(&p->free_list, cf, link);
}
}
}
mtx_unlock(&p->free_lock);
}
/*
* Count buffers
*/
void
mbp_count(struct mbpool *p, u_int *used, u_int *card, u_int *free)
{
u_int i, b;
struct mbpage *pg;
struct mbtrail *tr;
struct mbfree *cf;
*used = *card = *free = 0;
for (i = 0; i < p->npages; i++) {
pg = &p->pages[i];
for (b = 0; b < p->nchunks; b++) {
tr = C2T(p, N2C(p, pg, b));
if (tr->page & MBP_CARD)
(*card)++;
if (tr->page & MBP_USED)
(*used)++;
}
}
mtx_lock(&p->free_lock);
SLIST_FOREACH(cf, &p->free_list, link)
*free++;
mtx_unlock(&p->free_lock);
}
/*
* Get the buffer from a handle and clear the card flag.
*/
void *
mbp_get(struct mbpool *p, uint32_t h)
{
struct mbfree *cf;
struct mbtrail *tr;
cf = N2C(p, &p->pages[HPAGE(h)], HCHUNK(h));
tr = C2T(p, cf);
#ifdef DIAGNOSTIC
if (!(tr->page & MBP_CARD))
printf("%s: (%s) chunk %u page %u not on card\n", __func__,
p->name, HCHUNK(h), HPAGE(h));
#endif
tr->page &= ~MBP_CARD;
return (cf);
}
/*
* Get the buffer from a handle and keep the card flag.
*/
void *
mbp_get_keep(struct mbpool *p, uint32_t h)
{
struct mbfree *cf;
struct mbtrail *tr;
cf = N2C(p, &p->pages[HPAGE(h)], HCHUNK(h));
tr = C2T(p, cf);
#ifdef DIAGNOSTIC
if (!(tr->page & MBP_CARD))
printf("%s: (%s) chunk %u page %u not on card\n", __func__,
p->name, HCHUNK(h), HPAGE(h));
#endif
return (cf);
}
/*
* sync the chunk
*/
void
mbp_sync(struct mbpool *p, uint32_t h, bus_addr_t off, bus_size_t len, u_int op)
{
#if 0
bus_dmamap_sync_size(p->dmat, p->pages[HPAGE(h)].map,
HCHUNK(h) * p->chunk_size + off, len, op);
#endif
}