FreeBSD-5.3/sys/kern/subr_rman.c
/*
* Copyright 1998 Massachusetts Institute of Technology
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that both the above copyright notice and this
* permission notice appear in all copies, that both the above
* copyright notice and this permission notice appear in all
* supporting documentation, and that the name of M.I.T. not be used
* in advertising or publicity pertaining to distribution of the
* software without specific, written prior permission. M.I.T. makes
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied
* warranty.
*
* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
* SHALL M.I.T. 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.
*/
/*
* The kernel resource manager. This code is responsible for keeping track
* of hardware resources which are apportioned out to various drivers.
* It does not actually assign those resources, and it is not expected
* that end-device drivers will call into this code directly. Rather,
* the code which implements the buses that those devices are attached to,
* and the code which manages CPU resources, will call this code, and the
* end-device drivers will make upcalls to that code to actually perform
* the allocation.
*
* There are two sorts of resources managed by this code. The first is
* the more familiar array (RMAN_ARRAY) type; resources in this class
* consist of a sequence of individually-allocatable objects which have
* been numbered in some well-defined order. Most of the resources
* are of this type, as it is the most familiar. The second type is
* called a gauge (RMAN_GAUGE), and models fungible resources (i.e.,
* resources in which each instance is indistinguishable from every
* other instance). The principal anticipated application of gauges
* is in the context of power consumption, where a bus may have a specific
* power budget which all attached devices share. RMAN_GAUGE is not
* implemented yet.
*
* For array resources, we make one simplifying assumption: two clients
* sharing the same resource must use the same range of indices. That
* is to say, sharing of overlapping-but-not-identical regions is not
* permitted.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/subr_rman.c,v 1.35.2.1 2004/08/23 05:12:36 njl Exp $");
#define __RMAN_RESOURCE_VISIBLE
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/bus.h> /* XXX debugging */
#include <machine/bus.h>
#include <sys/rman.h>
#include <sys/sysctl.h>
int rman_debug = 0;
TUNABLE_INT("debug.rman_debug", &rman_debug);
SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RW,
&rman_debug, 0, "rman debug");
#define DPRINTF(params) if (rman_debug) printf params
static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
struct rman_head rman_head;
static struct mtx rman_mtx; /* mutex to protect rman_head */
static int int_rman_activate_resource(struct rman *rm, struct resource *r,
struct resource **whohas);
static int int_rman_deactivate_resource(struct resource *r);
static int int_rman_release_resource(struct rman *rm, struct resource *r);
int
rman_init(struct rman *rm)
{
static int once;
if (once == 0) {
once = 1;
TAILQ_INIT(&rman_head);
mtx_init(&rman_mtx, "rman head", NULL, MTX_DEF);
}
if (rm->rm_type == RMAN_UNINIT)
panic("rman_init");
if (rm->rm_type == RMAN_GAUGE)
panic("implement RMAN_GAUGE");
TAILQ_INIT(&rm->rm_list);
rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
if (rm->rm_mtx == 0)
return ENOMEM;
mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
mtx_lock(&rman_mtx);
TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
mtx_unlock(&rman_mtx);
return 0;
}
/*
* NB: this interface is not robust against programming errors which
* add multiple copies of the same region.
*/
int
rman_manage_region(struct rman *rm, u_long start, u_long end)
{
struct resource *r, *s;
DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
rm->rm_descr, start, end));
r = malloc(sizeof *r, M_RMAN, M_NOWAIT | M_ZERO);
if (r == 0)
return ENOMEM;
r->r_start = start;
r->r_end = end;
r->r_rm = rm;
mtx_lock(rm->rm_mtx);
for (s = TAILQ_FIRST(&rm->rm_list);
s && s->r_end < r->r_start;
s = TAILQ_NEXT(s, r_link))
;
if (s == NULL) {
TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
} else {
TAILQ_INSERT_BEFORE(s, r, r_link);
}
mtx_unlock(rm->rm_mtx);
return 0;
}
int
rman_fini(struct rman *rm)
{
struct resource *r;
mtx_lock(rm->rm_mtx);
TAILQ_FOREACH(r, &rm->rm_list, r_link) {
if (r->r_flags & RF_ALLOCATED) {
mtx_unlock(rm->rm_mtx);
return EBUSY;
}
}
/*
* There really should only be one of these if we are in this
* state and the code is working properly, but it can't hurt.
*/
while (!TAILQ_EMPTY(&rm->rm_list)) {
r = TAILQ_FIRST(&rm->rm_list);
TAILQ_REMOVE(&rm->rm_list, r, r_link);
free(r, M_RMAN);
}
mtx_unlock(rm->rm_mtx);
mtx_lock(&rman_mtx);
TAILQ_REMOVE(&rman_head, rm, rm_link);
mtx_unlock(&rman_mtx);
mtx_destroy(rm->rm_mtx);
free(rm->rm_mtx, M_RMAN);
return 0;
}
struct resource *
rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
u_long count, u_long bound, u_int flags,
struct device *dev)
{
u_int want_activate;
struct resource *r, *s, *rv;
u_long rstart, rend, amask, bmask;
rv = 0;
DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length "
"%#lx, flags %u, device %s\n", rm->rm_descr, start, end, count,
flags, dev == NULL ? "<null>" : device_get_nameunit(dev)));
want_activate = (flags & RF_ACTIVE);
flags &= ~RF_ACTIVE;
mtx_lock(rm->rm_mtx);
for (r = TAILQ_FIRST(&rm->rm_list);
r && r->r_end < start;
r = TAILQ_NEXT(r, r_link))
;
if (r == NULL) {
DPRINTF(("could not find a region\n"));
goto out;
}
amask = (1ul << RF_ALIGNMENT(flags)) - 1;
/* If bound is 0, bmask will also be 0 */
bmask = ~(bound - 1);
/*
* First try to find an acceptable totally-unshared region.
*/
for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
if (s->r_start > end) {
DPRINTF(("s->r_start (%#lx) > end (%#lx)\n", s->r_start, end));
break;
}
if (s->r_flags & RF_ALLOCATED) {
DPRINTF(("region is allocated\n"));
continue;
}
rstart = ulmax(s->r_start, start);
/*
* Try to find a region by adjusting to boundary and alignment
* until both conditions are satisfied. This is not an optimal
* algorithm, but in most cases it isn't really bad, either.
*/
do {
rstart = (rstart + amask) & ~amask;
if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
rstart += bound - (rstart & ~bmask);
} while ((rstart & amask) != 0 && rstart < end &&
rstart < s->r_end);
rend = ulmin(s->r_end, ulmax(rstart + count - 1, end));
if (rstart > rend) {
DPRINTF(("adjusted start exceeds end\n"));
continue;
}
DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
rstart, rend, (rend - rstart + 1), count));
if ((rend - rstart + 1) >= count) {
DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
rend, rstart, (rend - rstart + 1)));
if ((s->r_end - s->r_start + 1) == count) {
DPRINTF(("candidate region is entire chunk\n"));
rv = s;
rv->r_flags |= RF_ALLOCATED | flags;
rv->r_dev = dev;
goto out;
}
/*
* If s->r_start < rstart and
* s->r_end > rstart + count - 1, then
* we need to split the region into three pieces
* (the middle one will get returned to the user).
* Otherwise, we are allocating at either the
* beginning or the end of s, so we only need to
* split it in two. The first case requires
* two new allocations; the second requires but one.
*/
rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO);
if (rv == 0)
goto out;
rv->r_start = rstart;
rv->r_end = rstart + count - 1;
rv->r_flags = flags | RF_ALLOCATED;
rv->r_dev = dev;
rv->r_rm = rm;
if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
DPRINTF(("splitting region in three parts: "
"[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
s->r_start, rv->r_start - 1,
rv->r_start, rv->r_end,
rv->r_end + 1, s->r_end));
/*
* We are allocating in the middle.
*/
r = malloc(sizeof *r, M_RMAN, M_NOWAIT|M_ZERO);
if (r == 0) {
free(rv, M_RMAN);
rv = 0;
goto out;
}
r->r_start = rv->r_end + 1;
r->r_end = s->r_end;
r->r_flags = s->r_flags;
r->r_rm = rm;
s->r_end = rv->r_start - 1;
TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
r_link);
TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
r_link);
} else if (s->r_start == rv->r_start) {
DPRINTF(("allocating from the beginning\n"));
/*
* We are allocating at the beginning.
*/
s->r_start = rv->r_end + 1;
TAILQ_INSERT_BEFORE(s, rv, r_link);
} else {
DPRINTF(("allocating at the end\n"));
/*
* We are allocating at the end.
*/
s->r_end = rv->r_start - 1;
TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
r_link);
}
goto out;
}
}
/*
* Now find an acceptable shared region, if the client's requirements
* allow sharing. By our implementation restriction, a candidate
* region must match exactly by both size and sharing type in order
* to be considered compatible with the client's request. (The
* former restriction could probably be lifted without too much
* additional work, but this does not seem warranted.)
*/
DPRINTF(("no unshared regions found\n"));
if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
goto out;
for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
if (s->r_start > end)
break;
if ((s->r_flags & flags) != flags)
continue;
rstart = ulmax(s->r_start, start);
rend = ulmin(s->r_end, ulmax(start + count - 1, end));
if (s->r_start >= start && s->r_end <= end
&& (s->r_end - s->r_start + 1) == count &&
(s->r_start & amask) == 0 &&
((s->r_start ^ s->r_end) & bmask) == 0) {
rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO);
if (rv == 0)
goto out;
rv->r_start = s->r_start;
rv->r_end = s->r_end;
rv->r_flags = s->r_flags &
(RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
rv->r_dev = dev;
rv->r_rm = rm;
if (s->r_sharehead == 0) {
s->r_sharehead = malloc(sizeof *s->r_sharehead,
M_RMAN, M_NOWAIT | M_ZERO);
if (s->r_sharehead == 0) {
free(rv, M_RMAN);
rv = 0;
goto out;
}
LIST_INIT(s->r_sharehead);
LIST_INSERT_HEAD(s->r_sharehead, s,
r_sharelink);
s->r_flags |= RF_FIRSTSHARE;
}
rv->r_sharehead = s->r_sharehead;
LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
goto out;
}
}
/*
* We couldn't find anything.
*/
out:
/*
* If the user specified RF_ACTIVE in the initial flags,
* which is reflected in `want_activate', we attempt to atomically
* activate the resource. If this fails, we release the resource
* and indicate overall failure. (This behavior probably doesn't
* make sense for RF_TIMESHARE-type resources.)
*/
if (rv && want_activate) {
struct resource *whohas;
if (int_rman_activate_resource(rm, rv, &whohas)) {
int_rman_release_resource(rm, rv);
rv = 0;
}
}
mtx_unlock(rm->rm_mtx);
return (rv);
}
struct resource *
rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
u_int flags, struct device *dev)
{
return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
dev));
}
static int
int_rman_activate_resource(struct rman *rm, struct resource *r,
struct resource **whohas)
{
struct resource *s;
int ok;
/*
* If we are not timesharing, then there is nothing much to do.
* If we already have the resource, then there is nothing at all to do.
* If we are not on a sharing list with anybody else, then there is
* little to do.
*/
if ((r->r_flags & RF_TIMESHARE) == 0
|| (r->r_flags & RF_ACTIVE) != 0
|| r->r_sharehead == 0) {
r->r_flags |= RF_ACTIVE;
return 0;
}
ok = 1;
for (s = LIST_FIRST(r->r_sharehead); s && ok;
s = LIST_NEXT(s, r_sharelink)) {
if ((s->r_flags & RF_ACTIVE) != 0) {
ok = 0;
*whohas = s;
}
}
if (ok) {
r->r_flags |= RF_ACTIVE;
return 0;
}
return EBUSY;
}
int
rman_activate_resource(struct resource *r)
{
int rv;
struct resource *whohas;
struct rman *rm;
rm = r->r_rm;
mtx_lock(rm->rm_mtx);
rv = int_rman_activate_resource(rm, r, &whohas);
mtx_unlock(rm->rm_mtx);
return rv;
}
int
rman_await_resource(struct resource *r, int pri, int timo)
{
int rv;
struct resource *whohas;
struct rman *rm;
rm = r->r_rm;
mtx_lock(rm->rm_mtx);
for (;;) {
rv = int_rman_activate_resource(rm, r, &whohas);
if (rv != EBUSY)
return (rv); /* returns with mutex held */
if (r->r_sharehead == 0)
panic("rman_await_resource");
whohas->r_flags |= RF_WANTED;
rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
if (rv) {
mtx_unlock(rm->rm_mtx);
return (rv);
}
}
}
static int
int_rman_deactivate_resource(struct resource *r)
{
r->r_flags &= ~RF_ACTIVE;
if (r->r_flags & RF_WANTED) {
r->r_flags &= ~RF_WANTED;
wakeup(r->r_sharehead);
}
return 0;
}
int
rman_deactivate_resource(struct resource *r)
{
struct rman *rm;
rm = r->r_rm;
mtx_lock(rm->rm_mtx);
int_rman_deactivate_resource(r);
mtx_unlock(rm->rm_mtx);
return 0;
}
static int
int_rman_release_resource(struct rman *rm, struct resource *r)
{
struct resource *s, *t;
if (r->r_flags & RF_ACTIVE)
int_rman_deactivate_resource(r);
/*
* Check for a sharing list first. If there is one, then we don't
* have to think as hard.
*/
if (r->r_sharehead) {
/*
* If a sharing list exists, then we know there are at
* least two sharers.
*
* If we are in the main circleq, appoint someone else.
*/
LIST_REMOVE(r, r_sharelink);
s = LIST_FIRST(r->r_sharehead);
if (r->r_flags & RF_FIRSTSHARE) {
s->r_flags |= RF_FIRSTSHARE;
TAILQ_INSERT_BEFORE(r, s, r_link);
TAILQ_REMOVE(&rm->rm_list, r, r_link);
}
/*
* Make sure that the sharing list goes away completely
* if the resource is no longer being shared at all.
*/
if (LIST_NEXT(s, r_sharelink) == 0) {
free(s->r_sharehead, M_RMAN);
s->r_sharehead = 0;
s->r_flags &= ~RF_FIRSTSHARE;
}
goto out;
}
/*
* Look at the adjacent resources in the list and see if our
* segment can be merged with any of them. If either of the
* resources is allocated or is not exactly adjacent then they
* cannot be merged with our segment.
*/
s = TAILQ_PREV(r, resource_head, r_link);
if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
s->r_end + 1 != r->r_start))
s = NULL;
t = TAILQ_NEXT(r, r_link);
if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
r->r_end + 1 != t->r_start))
t = NULL;
if (s != NULL && t != NULL) {
/*
* Merge all three segments.
*/
s->r_end = t->r_end;
TAILQ_REMOVE(&rm->rm_list, r, r_link);
TAILQ_REMOVE(&rm->rm_list, t, r_link);
free(t, M_RMAN);
} else if (s != NULL) {
/*
* Merge previous segment with ours.
*/
s->r_end = r->r_end;
TAILQ_REMOVE(&rm->rm_list, r, r_link);
} else if (t != NULL) {
/*
* Merge next segment with ours.
*/
t->r_start = r->r_start;
TAILQ_REMOVE(&rm->rm_list, r, r_link);
} else {
/*
* At this point, we know there is nothing we
* can potentially merge with, because on each
* side, there is either nothing there or what is
* there is still allocated. In that case, we don't
* want to remove r from the list; we simply want to
* change it to an unallocated region and return
* without freeing anything.
*/
r->r_flags &= ~RF_ALLOCATED;
return 0;
}
out:
free(r, M_RMAN);
return 0;
}
int
rman_release_resource(struct resource *r)
{
int rv;
struct rman *rm = r->r_rm;
mtx_lock(rm->rm_mtx);
rv = int_rman_release_resource(rm, r);
mtx_unlock(rm->rm_mtx);
return (rv);
}
uint32_t
rman_make_alignment_flags(uint32_t size)
{
int i;
/*
* Find the hightest bit set, and add one if more than one bit
* set. We're effectively computing the ceil(log2(size)) here.
*/
for (i = 31; i > 0; i--)
if ((1 << i) & size)
break;
if (~(1 << i) & size)
i++;
return(RF_ALIGNMENT_LOG2(i));
}
u_long
rman_get_start(struct resource *r)
{
return (r->r_start);
}
u_long
rman_get_end(struct resource *r)
{
return (r->r_end);
}
u_long
rman_get_size(struct resource *r)
{
return (r->r_end - r->r_start + 1);
}
u_int
rman_get_flags(struct resource *r)
{
return (r->r_flags);
}
void
rman_set_virtual(struct resource *r, void *v)
{
r->r_virtual = v;
}
void *
rman_get_virtual(struct resource *r)
{
return (r->r_virtual);
}
void
rman_set_bustag(struct resource *r, bus_space_tag_t t)
{
r->r_bustag = t;
}
bus_space_tag_t
rman_get_bustag(struct resource *r)
{
return (r->r_bustag);
}
void
rman_set_bushandle(struct resource *r, bus_space_handle_t h)
{
r->r_bushandle = h;
}
bus_space_handle_t
rman_get_bushandle(struct resource *r)
{
return (r->r_bushandle);
}
void
rman_set_rid(struct resource *r, int rid)
{
r->r_rid = rid;
}
void
rman_set_start(struct resource *r, u_long start)
{
r->r_start = start;
}
void
rman_set_end(struct resource *r, u_long end)
{
r->r_end = end;
}
int
rman_get_rid(struct resource *r)
{
return (r->r_rid);
}
struct device *
rman_get_device(struct resource *r)
{
return (r->r_dev);
}