1 // SPDX-License-Identifier: GPL-2.0
3  * Smp timebase synchronization for ppc.
11 #include <linux/smp.h>
15 #include <asm/smp.h>
42 		tbsync->race_result = add;  in enter_contest()
57 		tbsync->ack = 1;  in smp_generic_take_timebase()
58 		while (!tbsync->handshake)  in smp_generic_take_timebase()
62 		cmd = tbsync->cmd;  in smp_generic_take_timebase()
63 		tb = tbsync->tb;  in smp_generic_take_timebase()
65 		tbsync->ack = 0;  in smp_generic_take_timebase()
69 		while (tbsync->handshake)  in smp_generic_take_timebase()
73 		enter_contest(tbsync->mark, -1);  in smp_generic_take_timebase()
78 static int start_contest(int cmd, long offset, int num)  in start_contest()  argument
84 	tbsync->cmd = cmd;  in start_contest()
87 	for (i = -3; i < num; ) {  in start_contest()
89 		tbsync->tb = tb + offset;  in start_contest()
90 		tbsync->mark = mark = tb + 400;  in start_contest()
94 		tbsync->handshake = 1;  in start_contest()
95 		while (tbsync->ack)  in start_contest()
100 		tbsync->handshake = 0;  in start_contest()
103 		while (!tbsync->ack)  in start_contest()
107 			score += tbsync->race_result;  in start_contest()
115 	int i, score, score2, old, min=0, max=5000, offset=1000;  in smp_generic_give_timebase()  local
124 	while (!tbsync->ack)  in smp_generic_give_timebase()
130 	for (old = -1; old != offset ; offset = (min+max) / 2) {  in smp_generic_give_timebase()
131 		score = start_contest(kSetAndTest, offset, NUM_ITER);  in smp_generic_give_timebase()
133 		pr_debug("score %d, offset %d\n", score, offset );  in smp_generic_give_timebase()
136 			max = offset;  in smp_generic_give_timebase()
138 			min = offset;  in smp_generic_give_timebase()
139 		old = offset;  in smp_generic_give_timebase()
148 	offset = (score < score2) ? min : max;  in smp_generic_give_timebase()
152 		start_contest(kSetAndTest, offset, NUM_ITER/10);  in smp_generic_give_timebase()
154 		if ((score2 = start_contest(kTest, offset, NUM_ITER)) < 0)  in smp_generic_give_timebase()
155 			score2 = -score2;  in smp_generic_give_timebase()
159 	pr_debug("Final offset: %d (%d/%d)\n", offset, score2, NUM_ITER );  in smp_generic_give_timebase()
162 	tbsync->cmd = kExit;  in smp_generic_give_timebase()
164 	tbsync->handshake = 1;  in smp_generic_give_timebase()
165 	while (tbsync->ack)  in smp_generic_give_timebase()
167 	tbsync->handshake = 0;  in smp_generic_give_timebase()