17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
562387023Sdduvall * Common Development and Distribution License (the "License").
662387023Sdduvall * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate *
87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate * and limitations under the License.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate *
197c478bd9Sstevel@tonic-gate * CDDL HEADER END
207c478bd9Sstevel@tonic-gate */
2162387023Sdduvall
227c478bd9Sstevel@tonic-gate /*
2362387023Sdduvall * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
247c478bd9Sstevel@tonic-gate * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate */
267c478bd9Sstevel@tonic-gate
27f724721bSzh #include "bge_impl.h"
287c478bd9Sstevel@tonic-gate
297c478bd9Sstevel@tonic-gate /*
307c478bd9Sstevel@tonic-gate * Atomically decrement a counter, but only if it will remain
317c478bd9Sstevel@tonic-gate * strictly positive (greater than zero) afterwards. We return
327c478bd9Sstevel@tonic-gate * the decremented value if so, otherwise zero (in which case
337c478bd9Sstevel@tonic-gate * the counter is unchanged).
347c478bd9Sstevel@tonic-gate *
357c478bd9Sstevel@tonic-gate * This is used for keeping track of available resources such
367c478bd9Sstevel@tonic-gate * as transmit ring slots ...
377c478bd9Sstevel@tonic-gate */
387c478bd9Sstevel@tonic-gate uint64_t
bge_atomic_reserve(uint64_t * count_p,uint64_t n)397c478bd9Sstevel@tonic-gate bge_atomic_reserve(uint64_t *count_p, uint64_t n)
407c478bd9Sstevel@tonic-gate {
417c478bd9Sstevel@tonic-gate uint64_t oldval;
427c478bd9Sstevel@tonic-gate uint64_t newval;
437c478bd9Sstevel@tonic-gate
447c478bd9Sstevel@tonic-gate /* ATOMICALLY */
457c478bd9Sstevel@tonic-gate do {
467c478bd9Sstevel@tonic-gate oldval = *count_p;
477c478bd9Sstevel@tonic-gate newval = oldval - n;
487c478bd9Sstevel@tonic-gate if (oldval <= n)
497c478bd9Sstevel@tonic-gate return (0); /* no resources left */
50*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(count_p, oldval, newval) != oldval);
517c478bd9Sstevel@tonic-gate
527c478bd9Sstevel@tonic-gate return (newval);
537c478bd9Sstevel@tonic-gate }
547c478bd9Sstevel@tonic-gate
557c478bd9Sstevel@tonic-gate /*
567c478bd9Sstevel@tonic-gate * Atomically increment a counter
577c478bd9Sstevel@tonic-gate */
587c478bd9Sstevel@tonic-gate void
bge_atomic_renounce(uint64_t * count_p,uint64_t n)597c478bd9Sstevel@tonic-gate bge_atomic_renounce(uint64_t *count_p, uint64_t n)
607c478bd9Sstevel@tonic-gate {
617c478bd9Sstevel@tonic-gate uint64_t oldval;
627c478bd9Sstevel@tonic-gate uint64_t newval;
637c478bd9Sstevel@tonic-gate
647c478bd9Sstevel@tonic-gate /* ATOMICALLY */
657c478bd9Sstevel@tonic-gate do {
667c478bd9Sstevel@tonic-gate oldval = *count_p;
677c478bd9Sstevel@tonic-gate newval = oldval + n;
68*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(count_p, oldval, newval) != oldval);
697c478bd9Sstevel@tonic-gate }
707c478bd9Sstevel@tonic-gate
717c478bd9Sstevel@tonic-gate /*
727c478bd9Sstevel@tonic-gate * Atomically claim a slot in a descriptor ring
737c478bd9Sstevel@tonic-gate */
747c478bd9Sstevel@tonic-gate uint64_t
bge_atomic_claim(uint64_t * count_p,uint64_t limit)757c478bd9Sstevel@tonic-gate bge_atomic_claim(uint64_t *count_p, uint64_t limit)
767c478bd9Sstevel@tonic-gate {
777c478bd9Sstevel@tonic-gate uint64_t oldval;
787c478bd9Sstevel@tonic-gate uint64_t newval;
797c478bd9Sstevel@tonic-gate
807c478bd9Sstevel@tonic-gate /* ATOMICALLY */
817c478bd9Sstevel@tonic-gate do {
827c478bd9Sstevel@tonic-gate oldval = *count_p;
837c478bd9Sstevel@tonic-gate newval = NEXT(oldval, limit);
84*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(count_p, oldval, newval) != oldval);
857c478bd9Sstevel@tonic-gate
867c478bd9Sstevel@tonic-gate return (oldval);
877c478bd9Sstevel@tonic-gate }
887c478bd9Sstevel@tonic-gate
89931dca7dSgs /*
90931dca7dSgs * Atomically NEXT a 64-bit integer, returning the
91931dca7dSgs * value it had *before* the NEXT was applied
92931dca7dSgs */
93931dca7dSgs uint64_t
bge_atomic_next(uint64_t * sp,uint64_t limit)94931dca7dSgs bge_atomic_next(uint64_t *sp, uint64_t limit)
95931dca7dSgs {
96931dca7dSgs uint64_t oldval;
97931dca7dSgs uint64_t newval;
98931dca7dSgs
99931dca7dSgs /* ATOMICALLY */
100931dca7dSgs do {
101931dca7dSgs oldval = *sp;
102931dca7dSgs newval = NEXT(oldval, limit);
103*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(sp, oldval, newval) != oldval);
104931dca7dSgs
105931dca7dSgs return (oldval);
106931dca7dSgs }
107931dca7dSgs
108931dca7dSgs /*
109931dca7dSgs * Atomically decrement a counter
110931dca7dSgs */
111931dca7dSgs void
bge_atomic_sub64(uint64_t * count_p,uint64_t n)112931dca7dSgs bge_atomic_sub64(uint64_t *count_p, uint64_t n)
113931dca7dSgs {
114931dca7dSgs uint64_t oldval;
115931dca7dSgs uint64_t newval;
116931dca7dSgs
117931dca7dSgs /* ATOMICALLY */
118931dca7dSgs do {
119931dca7dSgs oldval = *count_p;
120931dca7dSgs newval = oldval - n;
121*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(count_p, oldval, newval) != oldval);
122931dca7dSgs }
123931dca7dSgs
1247c478bd9Sstevel@tonic-gate /*
1257c478bd9Sstevel@tonic-gate * Atomically clear bits in a 64-bit word, returning
1267c478bd9Sstevel@tonic-gate * the value it had *before* the bits were cleared.
1277c478bd9Sstevel@tonic-gate */
1287c478bd9Sstevel@tonic-gate uint64_t
bge_atomic_clr64(uint64_t * sp,uint64_t bits)1297c478bd9Sstevel@tonic-gate bge_atomic_clr64(uint64_t *sp, uint64_t bits)
1307c478bd9Sstevel@tonic-gate {
1317c478bd9Sstevel@tonic-gate uint64_t oldval;
1327c478bd9Sstevel@tonic-gate uint64_t newval;
1337c478bd9Sstevel@tonic-gate
1347c478bd9Sstevel@tonic-gate /* ATOMICALLY */
1357c478bd9Sstevel@tonic-gate do {
1367c478bd9Sstevel@tonic-gate oldval = *sp;
1377c478bd9Sstevel@tonic-gate newval = oldval & ~bits;
138*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_64(sp, oldval, newval) != oldval);
1397c478bd9Sstevel@tonic-gate
1407c478bd9Sstevel@tonic-gate return (oldval);
1417c478bd9Sstevel@tonic-gate }
1427c478bd9Sstevel@tonic-gate
1437c478bd9Sstevel@tonic-gate /*
1447c478bd9Sstevel@tonic-gate * Atomically shift a 32-bit word left, returning
1457c478bd9Sstevel@tonic-gate * the value it had *before* the shift was applied
1467c478bd9Sstevel@tonic-gate */
1477c478bd9Sstevel@tonic-gate uint32_t
bge_atomic_shl32(uint32_t * sp,uint_t count)1487c478bd9Sstevel@tonic-gate bge_atomic_shl32(uint32_t *sp, uint_t count)
1497c478bd9Sstevel@tonic-gate {
1507c478bd9Sstevel@tonic-gate uint32_t oldval;
1517c478bd9Sstevel@tonic-gate uint32_t newval;
1527c478bd9Sstevel@tonic-gate
1537c478bd9Sstevel@tonic-gate /* ATOMICALLY */
1547c478bd9Sstevel@tonic-gate do {
1557c478bd9Sstevel@tonic-gate oldval = *sp;
1567c478bd9Sstevel@tonic-gate newval = oldval << count;
157*75d94465SJosef 'Jeff' Sipek } while (atomic_cas_32(sp, oldval, newval) != oldval);
1587c478bd9Sstevel@tonic-gate
1597c478bd9Sstevel@tonic-gate return (oldval);
1607c478bd9Sstevel@tonic-gate }
161