1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24*0Sstevel@tonic-gate * Use is subject to license terms. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 28*0Sstevel@tonic-gate 29*0Sstevel@tonic-gate #include "sys/bge_impl.h" 30*0Sstevel@tonic-gate 31*0Sstevel@tonic-gate /* 32*0Sstevel@tonic-gate * Atomically decrement a counter, but only if it will remain 33*0Sstevel@tonic-gate * strictly positive (greater than zero) afterwards. We return 34*0Sstevel@tonic-gate * the decremented value if so, otherwise zero (in which case 35*0Sstevel@tonic-gate * the counter is unchanged). 36*0Sstevel@tonic-gate * 37*0Sstevel@tonic-gate * This is used for keeping track of available resources such 38*0Sstevel@tonic-gate * as transmit ring slots ... 39*0Sstevel@tonic-gate */ 40*0Sstevel@tonic-gate uint64_t 41*0Sstevel@tonic-gate bge_atomic_reserve(uint64_t *count_p, uint64_t n) 42*0Sstevel@tonic-gate { 43*0Sstevel@tonic-gate uint64_t oldval; 44*0Sstevel@tonic-gate uint64_t newval; 45*0Sstevel@tonic-gate 46*0Sstevel@tonic-gate /* ATOMICALLY */ 47*0Sstevel@tonic-gate do { 48*0Sstevel@tonic-gate oldval = *count_p; 49*0Sstevel@tonic-gate newval = oldval - n; 50*0Sstevel@tonic-gate if (oldval <= n) 51*0Sstevel@tonic-gate return (0); /* no resources left */ 52*0Sstevel@tonic-gate } while (cas64(count_p, oldval, newval) != oldval); 53*0Sstevel@tonic-gate 54*0Sstevel@tonic-gate return (newval); 55*0Sstevel@tonic-gate } 56*0Sstevel@tonic-gate 57*0Sstevel@tonic-gate /* 58*0Sstevel@tonic-gate * Atomically increment a counter 59*0Sstevel@tonic-gate */ 60*0Sstevel@tonic-gate void 61*0Sstevel@tonic-gate bge_atomic_renounce(uint64_t *count_p, uint64_t n) 62*0Sstevel@tonic-gate { 63*0Sstevel@tonic-gate uint64_t oldval; 64*0Sstevel@tonic-gate uint64_t newval; 65*0Sstevel@tonic-gate 66*0Sstevel@tonic-gate /* ATOMICALLY */ 67*0Sstevel@tonic-gate do { 68*0Sstevel@tonic-gate oldval = *count_p; 69*0Sstevel@tonic-gate newval = oldval + n; 70*0Sstevel@tonic-gate } while (cas64(count_p, oldval, newval) != oldval); 71*0Sstevel@tonic-gate } 72*0Sstevel@tonic-gate 73*0Sstevel@tonic-gate /* 74*0Sstevel@tonic-gate * Atomically claim a slot in a descriptor ring 75*0Sstevel@tonic-gate */ 76*0Sstevel@tonic-gate uint64_t 77*0Sstevel@tonic-gate bge_atomic_claim(uint64_t *count_p, uint64_t limit) 78*0Sstevel@tonic-gate { 79*0Sstevel@tonic-gate uint64_t oldval; 80*0Sstevel@tonic-gate uint64_t newval; 81*0Sstevel@tonic-gate 82*0Sstevel@tonic-gate /* ATOMICALLY */ 83*0Sstevel@tonic-gate do { 84*0Sstevel@tonic-gate oldval = *count_p; 85*0Sstevel@tonic-gate newval = NEXT(oldval, limit); 86*0Sstevel@tonic-gate } while (cas64(count_p, oldval, newval) != oldval); 87*0Sstevel@tonic-gate 88*0Sstevel@tonic-gate return (oldval); 89*0Sstevel@tonic-gate } 90*0Sstevel@tonic-gate 91*0Sstevel@tonic-gate /* 92*0Sstevel@tonic-gate * Atomically clear bits in a 64-bit word, returning 93*0Sstevel@tonic-gate * the value it had *before* the bits were cleared. 94*0Sstevel@tonic-gate */ 95*0Sstevel@tonic-gate uint64_t 96*0Sstevel@tonic-gate bge_atomic_clr64(uint64_t *sp, uint64_t bits) 97*0Sstevel@tonic-gate { 98*0Sstevel@tonic-gate uint64_t oldval; 99*0Sstevel@tonic-gate uint64_t newval; 100*0Sstevel@tonic-gate 101*0Sstevel@tonic-gate /* ATOMICALLY */ 102*0Sstevel@tonic-gate do { 103*0Sstevel@tonic-gate oldval = *sp; 104*0Sstevel@tonic-gate newval = oldval & ~bits; 105*0Sstevel@tonic-gate } while (cas64(sp, oldval, newval) != oldval); 106*0Sstevel@tonic-gate 107*0Sstevel@tonic-gate return (oldval); 108*0Sstevel@tonic-gate } 109*0Sstevel@tonic-gate 110*0Sstevel@tonic-gate /* 111*0Sstevel@tonic-gate * Atomically shift a 32-bit word left, returning 112*0Sstevel@tonic-gate * the value it had *before* the shift was applied 113*0Sstevel@tonic-gate */ 114*0Sstevel@tonic-gate uint32_t 115*0Sstevel@tonic-gate bge_atomic_shl32(uint32_t *sp, uint_t count) 116*0Sstevel@tonic-gate { 117*0Sstevel@tonic-gate uint32_t oldval; 118*0Sstevel@tonic-gate uint32_t newval; 119*0Sstevel@tonic-gate 120*0Sstevel@tonic-gate /* ATOMICALLY */ 121*0Sstevel@tonic-gate do { 122*0Sstevel@tonic-gate oldval = *sp; 123*0Sstevel@tonic-gate newval = oldval << count; 124*0Sstevel@tonic-gate } while (cas32(sp, oldval, newval) != oldval); 125*0Sstevel@tonic-gate 126*0Sstevel@tonic-gate return (oldval); 127*0Sstevel@tonic-gate } 128