freebsd-dev/sys/kern/subr_busdma_bounce.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1997, 1998 Justin T. Gibbs.
* 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,
* without modification, immediately at the beginning of the file.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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.
*/
/*
* Common code for managing bounce pages for bus_dma backends. As
* this code currently assumes it can access internal members of
* opaque types like bus_dma_tag_t and bus_dmamap it is #include'd in
* backends rather than being compiled standalone.
*
* Prerequisites:
*
* - M_BUSDMA malloc type
* - struct bus_dmamap
* - hw_busdma SYSCTL_NODE
* - macros to access the following fields of bus_dma_tag_t:
* - dmat_alignment()
* - dmat_flags()
* - dmat_lowaddr()
* - dmat_lockfunc()
* - dmat_lockarg()
*/
#include <sys/kthread.h>
#include <sys/sched.h>
struct bounce_page {
vm_offset_t vaddr; /* kva of bounce buffer */
bus_addr_t busaddr; /* Physical address */
vm_offset_t datavaddr; /* kva of client data */
#if defined(__amd64__) || defined(__i386__)
vm_page_t datapage[2]; /* physical page(s) of client data */
#else
vm_page_t datapage; /* physical page of client data */
#endif
vm_offset_t dataoffs; /* page offset of client data */
bus_size_t datacount; /* client data count */
STAILQ_ENTRY(bounce_page) links;
};
struct bounce_zone {
STAILQ_ENTRY(bounce_zone) links;
STAILQ_HEAD(, bounce_page) bounce_page_list;
STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
int total_bpages;
int free_bpages;
int reserved_bpages;
int active_bpages;
int total_bounced;
int total_deferred;
int map_count;
#ifdef dmat_domain
int domain;
#endif
bus_size_t alignment;
bus_addr_t lowaddr;
char zoneid[8];
char lowaddrid[20];
struct sysctl_ctx_list sysctl_tree;
struct sysctl_oid *sysctl_tree_top;
};
static struct mtx bounce_lock;
static int total_bpages;
static int busdma_zonecount;
static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
static MALLOC_DEFINE(M_BOUNCE, "bounce", "busdma bounce pages");
SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
"Total bounce pages");
static void busdma_thread(void *);
static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
int commit);
static int
_bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
{
struct bounce_zone *bz;
/* Reserve Necessary Bounce Pages */
mtx_lock(&bounce_lock);
if (flags & BUS_DMA_NOWAIT) {
if (reserve_bounce_pages(dmat, map, 0) != 0) {
map->pagesneeded = 0;
mtx_unlock(&bounce_lock);
return (ENOMEM);
}
} else {
if (reserve_bounce_pages(dmat, map, 1) != 0) {
/* Queue us for resources */
bz = dmat->bounce_zone;
STAILQ_INSERT_TAIL(&bz->bounce_map_waitinglist, map,
links);
mtx_unlock(&bounce_lock);
return (EINPROGRESS);
}
}
mtx_unlock(&bounce_lock);
return (0);
}
static void
init_bounce_pages(void *dummy __unused)
{
total_bpages = 0;
STAILQ_INIT(&bounce_zone_list);
STAILQ_INIT(&bounce_map_callbacklist);
mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
}
SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
static struct sysctl_ctx_list *
busdma_sysctl_tree(struct bounce_zone *bz)
{
return (&bz->sysctl_tree);
}
static struct sysctl_oid *
busdma_sysctl_tree_top(struct bounce_zone *bz)
{
return (bz->sysctl_tree_top);
}
static int
alloc_bounce_zone(bus_dma_tag_t dmat)
{
struct bounce_zone *bz;
bool start_thread;
/* Check to see if we already have a suitable zone */
STAILQ_FOREACH(bz, &bounce_zone_list, links) {
if ((dmat_alignment(dmat) <= bz->alignment) &&
#ifdef dmat_domain
dmat_domain(dmat) == bz->domain &&
#endif
(dmat_lowaddr(dmat) >= bz->lowaddr)) {
dmat->bounce_zone = bz;
return (0);
}
}
if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_BUSDMA,
M_NOWAIT | M_ZERO)) == NULL)
return (ENOMEM);
STAILQ_INIT(&bz->bounce_page_list);
STAILQ_INIT(&bz->bounce_map_waitinglist);
bz->free_bpages = 0;
bz->reserved_bpages = 0;
bz->active_bpages = 0;
bz->lowaddr = dmat_lowaddr(dmat);
bz->alignment = MAX(dmat_alignment(dmat), PAGE_SIZE);
bz->map_count = 0;
#ifdef dmat_domain
bz->domain = dmat_domain(dmat);
#endif
snprintf(bz->zoneid, sizeof(bz->zoneid), "zone%d", busdma_zonecount);
busdma_zonecount++;
snprintf(bz->lowaddrid, sizeof(bz->lowaddrid), "%#jx",
(uintmax_t)bz->lowaddr);
start_thread = STAILQ_EMPTY(&bounce_zone_list);
STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
dmat->bounce_zone = bz;
sysctl_ctx_init(&bz->sysctl_tree);
bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
if (bz->sysctl_tree_top == NULL) {
sysctl_ctx_free(&bz->sysctl_tree);
return (0); /* XXX error code? */
}
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
"Total bounce pages");
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
"Free bounce pages");
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
"Reserved bounce pages");
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
"Active bounce pages");
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
"Total bounce requests (pages bounced)");
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
"Total bounce requests that were deferred");
SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"alignment", CTLFLAG_RD, &bz->alignment, "");
#ifdef dmat_domain
SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
"domain", CTLFLAG_RD, &bz->domain, 0,
"memory domain");
#endif
if (start_thread) {
if (kproc_create(busdma_thread, NULL, NULL, 0, 0, "busdma") !=
0)
printf("failed to create busdma thread");
}
return (0);
}
static int
alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
{
struct bounce_zone *bz;
int count;
bz = dmat->bounce_zone;
count = 0;
while (numpages > 0) {
struct bounce_page *bpage;
#ifdef dmat_domain
bpage = malloc_domainset(sizeof(*bpage), M_BUSDMA,
DOMAINSET_PREF(bz->domain), M_NOWAIT | M_ZERO);
#else
bpage = malloc(sizeof(*bpage), M_BUSDMA, M_NOWAIT | M_ZERO);
#endif
if (bpage == NULL)
break;
#ifdef dmat_domain
bpage->vaddr = (vm_offset_t)contigmalloc_domainset(PAGE_SIZE,
M_BOUNCE, DOMAINSET_PREF(bz->domain), M_NOWAIT,
0ul, bz->lowaddr, PAGE_SIZE, 0);
#else
bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_BOUNCE,
M_NOWAIT, 0ul, bz->lowaddr, PAGE_SIZE, 0);
#endif
if (bpage->vaddr == 0) {
free(bpage, M_BUSDMA);
break;
}
bpage->busaddr = pmap_kextract(bpage->vaddr);
mtx_lock(&bounce_lock);
STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
total_bpages++;
bz->total_bpages++;
bz->free_bpages++;
mtx_unlock(&bounce_lock);
count++;
numpages--;
}
return (count);
}
static int
reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
{
struct bounce_zone *bz;
int pages;
mtx_assert(&bounce_lock, MA_OWNED);
bz = dmat->bounce_zone;
pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
return (map->pagesneeded - (map->pagesreserved + pages));
bz->free_bpages -= pages;
bz->reserved_bpages += pages;
map->pagesreserved += pages;
pages = map->pagesneeded - map->pagesreserved;
return (pages);
}
#if defined(__amd64__) || defined(__i386__)
static bus_addr_t
add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
vm_paddr_t addr1, vm_paddr_t addr2, bus_size_t size)
#else
static bus_addr_t
add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
bus_addr_t addr, bus_size_t size)
#endif
{
struct bounce_zone *bz;
struct bounce_page *bpage;
KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
KASSERT(map != NULL, ("add_bounce_page: bad map %p", map));
#if defined(__amd64__) || defined(__i386__)
KASSERT(map != &nobounce_dmamap, ("add_bounce_page: bad map %p", map));
#endif
#ifdef __riscv
KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
("add_bounce_page: bad map %p", map));
#endif
bz = dmat->bounce_zone;
if (map->pagesneeded == 0)
panic("add_bounce_page: map doesn't need any pages");
map->pagesneeded--;
if (map->pagesreserved == 0)
panic("add_bounce_page: map doesn't need any pages");
map->pagesreserved--;
mtx_lock(&bounce_lock);
bpage = STAILQ_FIRST(&bz->bounce_page_list);
if (bpage == NULL)
panic("add_bounce_page: free page list is empty");
STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
bz->reserved_bpages--;
bz->active_bpages++;
mtx_unlock(&bounce_lock);
if (dmat_flags(dmat) & BUS_DMA_KEEP_PG_OFFSET) {
/* Page offset needs to be preserved. */
#if defined(__amd64__) || defined(__i386__)
bpage->vaddr |= addr1 & PAGE_MASK;
bpage->busaddr |= addr1 & PAGE_MASK;
KASSERT(addr2 == 0,
("Trying to bounce multiple pages with BUS_DMA_KEEP_PG_OFFSET"));
#else
bpage->vaddr |= addr & PAGE_MASK;
bpage->busaddr |= addr & PAGE_MASK;
#endif
}
bpage->datavaddr = vaddr;
#if defined(__amd64__) || defined(__i386__)
bpage->datapage[0] = PHYS_TO_VM_PAGE(addr1);
KASSERT((addr2 & PAGE_MASK) == 0, ("Second page is not aligned"));
bpage->datapage[1] = PHYS_TO_VM_PAGE(addr2);
bpage->dataoffs = addr1 & PAGE_MASK;
#else
bpage->datapage = PHYS_TO_VM_PAGE(addr);
bpage->dataoffs = addr & PAGE_MASK;
#endif
bpage->datacount = size;
STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
return (bpage->busaddr);
}
static void
free_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
{
struct bounce_page *bpage;
struct bounce_zone *bz;
bool schedule_thread;
u_int count;
if (STAILQ_EMPTY(&map->bpages))
return;
bz = dmat->bounce_zone;
count = 0;
schedule_thread = false;
STAILQ_FOREACH(bpage, &map->bpages, links) {
bpage->datavaddr = 0;
bpage->datacount = 0;
if (dmat_flags(dmat) & BUS_DMA_KEEP_PG_OFFSET) {
/*
* Reset the bounce page to start at offset 0.
* Other uses of this bounce page may need to
* store a full page of data and/or assume it
* starts on a page boundary.
*/
bpage->vaddr &= ~PAGE_MASK;
bpage->busaddr &= ~PAGE_MASK;
}
count++;
}
mtx_lock(&bounce_lock);
STAILQ_CONCAT(&bz->bounce_page_list, &map->bpages);
bz->free_bpages += count;
bz->active_bpages -= count;
while ((map = STAILQ_FIRST(&bz->bounce_map_waitinglist)) != NULL) {
if (reserve_bounce_pages(map->dmat, map, 1) != 0)
break;
STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
bz->total_deferred++;
schedule_thread = true;
}
mtx_unlock(&bounce_lock);
if (schedule_thread)
wakeup(&bounce_map_callbacklist);
}
static void
busdma_thread(void *dummy __unused)
{
STAILQ_HEAD(, bus_dmamap) callbacklist;
bus_dma_tag_t dmat;
struct bus_dmamap *map, *nmap;
thread_lock(curthread);
sched_class(curthread, PRI_ITHD);
sched_ithread_prio(curthread, PI_SWI(SWI_BUSDMA));
thread_unlock(curthread);
for (;;) {
mtx_lock(&bounce_lock);
while (STAILQ_EMPTY(&bounce_map_callbacklist))
mtx_sleep(&bounce_map_callbacklist, &bounce_lock, 0,
"-", 0);
STAILQ_INIT(&callbacklist);
STAILQ_CONCAT(&callbacklist, &bounce_map_callbacklist);
mtx_unlock(&bounce_lock);
STAILQ_FOREACH_SAFE(map, &callbacklist, links, nmap) {
dmat = map->dmat;
dmat_lockfunc(dmat)(dmat_lockfuncarg(dmat),
BUS_DMA_LOCK);
bus_dmamap_load_mem(map->dmat, map, &map->mem,
map->callback, map->callback_arg, BUS_DMA_WAITOK);
dmat_lockfunc(dmat)(dmat_lockfuncarg(dmat),
BUS_DMA_UNLOCK);
}
}
}