diff options
Diffstat (limited to 'arch/ppc/kernel/smp-tbsync.c')
-rw-r--r-- | arch/ppc/kernel/smp-tbsync.c | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/arch/ppc/kernel/smp-tbsync.c b/arch/ppc/kernel/smp-tbsync.c deleted file mode 100644 index d0cf3f86931d..000000000000 --- a/arch/ppc/kernel/smp-tbsync.c +++ /dev/null | |||
@@ -1,180 +0,0 @@ | |||
1 | /* | ||
2 | * Smp timebase synchronization for ppc. | ||
3 | * | ||
4 | * Copyright (C) 2003 Samuel Rydh (samuel@ibrium.se) | ||
5 | * | ||
6 | */ | ||
7 | |||
8 | #include <linux/kernel.h> | ||
9 | #include <linux/sched.h> | ||
10 | #include <linux/smp.h> | ||
11 | #include <linux/unistd.h> | ||
12 | #include <linux/init.h> | ||
13 | #include <asm/atomic.h> | ||
14 | #include <asm/smp.h> | ||
15 | #include <asm/time.h> | ||
16 | |||
17 | #define NUM_ITER 300 | ||
18 | |||
19 | enum { | ||
20 | kExit=0, kSetAndTest, kTest | ||
21 | }; | ||
22 | |||
23 | static struct { | ||
24 | volatile int tbu; | ||
25 | volatile int tbl; | ||
26 | volatile int mark; | ||
27 | volatile int cmd; | ||
28 | volatile int handshake; | ||
29 | int filler[3]; | ||
30 | |||
31 | volatile int ack; | ||
32 | int filler2[7]; | ||
33 | |||
34 | volatile int race_result; | ||
35 | } *tbsync; | ||
36 | |||
37 | static volatile int running; | ||
38 | |||
39 | static void __devinit | ||
40 | enter_contest( int mark, int add ) | ||
41 | { | ||
42 | while( (int)(get_tbl() - mark) < 0 ) | ||
43 | tbsync->race_result = add; | ||
44 | } | ||
45 | |||
46 | void __devinit | ||
47 | smp_generic_take_timebase( void ) | ||
48 | { | ||
49 | int cmd, tbl, tbu; | ||
50 | unsigned long flags; | ||
51 | |||
52 | local_irq_save(flags); | ||
53 | while( !running ) | ||
54 | ; | ||
55 | rmb(); | ||
56 | |||
57 | for( ;; ) { | ||
58 | tbsync->ack = 1; | ||
59 | while( !tbsync->handshake ) | ||
60 | ; | ||
61 | rmb(); | ||
62 | |||
63 | cmd = tbsync->cmd; | ||
64 | tbl = tbsync->tbl; | ||
65 | tbu = tbsync->tbu; | ||
66 | tbsync->ack = 0; | ||
67 | if( cmd == kExit ) | ||
68 | break; | ||
69 | |||
70 | if( cmd == kSetAndTest ) { | ||
71 | while( tbsync->handshake ) | ||
72 | ; | ||
73 | asm volatile ("mttbl %0" :: "r" (tbl) ); | ||
74 | asm volatile ("mttbu %0" :: "r" (tbu) ); | ||
75 | } else { | ||
76 | while( tbsync->handshake ) | ||
77 | ; | ||
78 | } | ||
79 | enter_contest( tbsync->mark, -1 ); | ||
80 | } | ||
81 | local_irq_restore(flags); | ||
82 | } | ||
83 | |||
84 | static int __devinit | ||
85 | start_contest( int cmd, int offset, int num ) | ||
86 | { | ||
87 | int i, tbu, tbl, mark, score=0; | ||
88 | |||
89 | tbsync->cmd = cmd; | ||
90 | |||
91 | local_irq_disable(); | ||
92 | for( i=-3; i<num; ) { | ||
93 | tbl = get_tbl() + 400; | ||
94 | tbsync->tbu = tbu = get_tbu(); | ||
95 | tbsync->tbl = tbl + offset; | ||
96 | tbsync->mark = mark = tbl + 400; | ||
97 | |||
98 | wmb(); | ||
99 | |||
100 | tbsync->handshake = 1; | ||
101 | while( tbsync->ack ) | ||
102 | ; | ||
103 | |||
104 | while( (int)(get_tbl() - tbl) <= 0 ) | ||
105 | ; | ||
106 | tbsync->handshake = 0; | ||
107 | enter_contest( mark, 1 ); | ||
108 | |||
109 | while( !tbsync->ack ) | ||
110 | ; | ||
111 | |||
112 | if( tbsync->tbu != get_tbu() || ((tbsync->tbl ^ get_tbl()) & 0x80000000) ) | ||
113 | continue; | ||
114 | if( i++ > 0 ) | ||
115 | score += tbsync->race_result; | ||
116 | } | ||
117 | local_irq_enable(); | ||
118 | return score; | ||
119 | } | ||
120 | |||
121 | void __devinit | ||
122 | smp_generic_give_timebase( void ) | ||
123 | { | ||
124 | int i, score, score2, old, min=0, max=5000, offset=1000; | ||
125 | |||
126 | printk("Synchronizing timebase\n"); | ||
127 | |||
128 | /* if this fails then this kernel won't work anyway... */ | ||
129 | tbsync = kzalloc( sizeof(*tbsync), GFP_KERNEL ); | ||
130 | mb(); | ||
131 | running = 1; | ||
132 | |||
133 | while( !tbsync->ack ) | ||
134 | ; | ||
135 | |||
136 | /* binary search */ | ||
137 | for( old=-1 ; old != offset ; offset=(min+max)/2 ) { | ||
138 | score = start_contest( kSetAndTest, offset, NUM_ITER ); | ||
139 | |||
140 | printk("score %d, offset %d\n", score, offset ); | ||
141 | |||
142 | if( score > 0 ) | ||
143 | max = offset; | ||
144 | else | ||
145 | min = offset; | ||
146 | old = offset; | ||
147 | } | ||
148 | score = start_contest( kSetAndTest, min, NUM_ITER ); | ||
149 | score2 = start_contest( kSetAndTest, max, NUM_ITER ); | ||
150 | |||
151 | printk( "Min %d (score %d), Max %d (score %d)\n", min, score, max, score2 ); | ||
152 | score = abs( score ); | ||
153 | score2 = abs( score2 ); | ||
154 | offset = (score < score2) ? min : max; | ||
155 | |||
156 | /* guard against inaccurate mttb */ | ||
157 | for( i=0; i<10; i++ ) { | ||
158 | start_contest( kSetAndTest, offset, NUM_ITER/10 ); | ||
159 | |||
160 | if( (score2=start_contest(kTest, offset, NUM_ITER)) < 0 ) | ||
161 | score2 = -score2; | ||
162 | if( score2 <= score || score2 < 20 ) | ||
163 | break; | ||
164 | } | ||
165 | printk("Final offset: %d (%d/%d)\n", offset, score2, NUM_ITER ); | ||
166 | |||
167 | /* exiting */ | ||
168 | tbsync->cmd = kExit; | ||
169 | wmb(); | ||
170 | tbsync->handshake = 1; | ||
171 | while( tbsync->ack ) | ||
172 | ; | ||
173 | tbsync->handshake = 0; | ||
174 | kfree( tbsync ); | ||
175 | tbsync = NULL; | ||
176 | running = 0; | ||
177 | |||
178 | /* all done */ | ||
179 | smp_tb_synchronized = 1; | ||
180 | } | ||