Remove obsolete #include <linux/config.h>
[linux-3.10.git] / arch / powerpc / platforms / cell / smp.c
1 /*
2  * SMP support for BPA machines.
3  *
4  * Dave Engebretsen, Peter Bergner, and
5  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
6  *
7  * Plus various changes from other IBM teams...
8  *
9  *      This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  */
14
15 #undef DEBUG
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/init.h>
24 #include <linux/spinlock.h>
25 #include <linux/cache.h>
26 #include <linux/err.h>
27 #include <linux/sysdev.h>
28 #include <linux/cpu.h>
29
30 #include <asm/ptrace.h>
31 #include <asm/atomic.h>
32 #include <asm/irq.h>
33 #include <asm/page.h>
34 #include <asm/pgtable.h>
35 #include <asm/io.h>
36 #include <asm/prom.h>
37 #include <asm/smp.h>
38 #include <asm/paca.h>
39 #include <asm/time.h>
40 #include <asm/machdep.h>
41 #include <asm/cputable.h>
42 #include <asm/firmware.h>
43 #include <asm/system.h>
44 #include <asm/rtas.h>
45
46 #include "interrupt.h"
47
48 #ifdef DEBUG
49 #define DBG(fmt...) udbg_printf(fmt)
50 #else
51 #define DBG(fmt...)
52 #endif
53
54 /*
55  * The primary thread of each non-boot processor is recorded here before
56  * smp init.
57  */
58 static cpumask_t of_spin_map;
59
60 extern void pSeries_secondary_smp_init(unsigned long);
61
62 /**
63  * smp_startup_cpu() - start the given cpu
64  *
65  * At boot time, there is nothing to do for primary threads which were
66  * started from Open Firmware.  For anything else, call RTAS with the
67  * appropriate start location.
68  *
69  * Returns:
70  *      0       - failure
71  *      1       - success
72  */
73 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
74 {
75         int status;
76         unsigned long start_here = __pa((u32)*((unsigned long *)
77                                                pSeries_secondary_smp_init));
78         unsigned int pcpu;
79         int start_cpu;
80
81         if (cpu_isset(lcpu, of_spin_map))
82                 /* Already started by OF and sitting in spin loop */
83                 return 1;
84
85         pcpu = get_hard_smp_processor_id(lcpu);
86
87         /* Fixup atomic count: it exited inside IRQ handler. */
88         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
89
90         /*
91          * If the RTAS start-cpu token does not exist then presume the
92          * cpu is already spinning.
93          */
94         start_cpu = rtas_token("start-cpu");
95         if (start_cpu == RTAS_UNKNOWN_SERVICE)
96                 return 1;
97
98         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu);
99         if (status != 0) {
100                 printk(KERN_ERR "start-cpu failed: %i\n", status);
101                 return 0;
102         }
103
104         return 1;
105 }
106
107 static void smp_iic_message_pass(int target, int msg)
108 {
109         unsigned int i;
110
111         if (target < NR_CPUS) {
112                 iic_cause_IPI(target, msg);
113         } else {
114                 for_each_online_cpu(i) {
115                         if (target == MSG_ALL_BUT_SELF
116                             && i == smp_processor_id())
117                                 continue;
118                         iic_cause_IPI(i, msg);
119                 }
120         }
121 }
122
123 static int __init smp_iic_probe(void)
124 {
125         iic_request_IPIs();
126
127         return cpus_weight(cpu_possible_map);
128 }
129
130 static void __devinit smp_iic_setup_cpu(int cpu)
131 {
132         if (cpu != boot_cpuid)
133                 iic_setup_cpu();
134 }
135
136 static DEFINE_SPINLOCK(timebase_lock);
137 static unsigned long timebase = 0;
138
139 static void __devinit cell_give_timebase(void)
140 {
141         spin_lock(&timebase_lock);
142         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
143         timebase = get_tb();
144         spin_unlock(&timebase_lock);
145
146         while (timebase)
147                 barrier();
148         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
149 }
150
151 static void __devinit cell_take_timebase(void)
152 {
153         while (!timebase)
154                 barrier();
155         spin_lock(&timebase_lock);
156         set_tb(timebase >> 32, timebase & 0xffffffff);
157         timebase = 0;
158         spin_unlock(&timebase_lock);
159 }
160
161 static void __devinit smp_cell_kick_cpu(int nr)
162 {
163         BUG_ON(nr < 0 || nr >= NR_CPUS);
164
165         if (!smp_startup_cpu(nr))
166                 return;
167
168         /*
169          * The processor is currently spinning, waiting for the
170          * cpu_start field to become non-zero After we set cpu_start,
171          * the processor will continue on to secondary_start
172          */
173         paca[nr].cpu_start = 1;
174 }
175
176 static int smp_cell_cpu_bootable(unsigned int nr)
177 {
178         /* Special case - we inhibit secondary thread startup
179          * during boot if the user requests it.  Odd-numbered
180          * cpus are assumed to be secondary threads.
181          */
182         if (system_state < SYSTEM_RUNNING &&
183             cpu_has_feature(CPU_FTR_SMT) &&
184             !smt_enabled_at_boot && nr % 2 != 0)
185                 return 0;
186
187         return 1;
188 }
189 static struct smp_ops_t bpa_iic_smp_ops = {
190         .message_pass   = smp_iic_message_pass,
191         .probe          = smp_iic_probe,
192         .kick_cpu       = smp_cell_kick_cpu,
193         .setup_cpu      = smp_iic_setup_cpu,
194         .cpu_bootable   = smp_cell_cpu_bootable,
195 };
196
197 /* This is called very early */
198 void __init smp_init_cell(void)
199 {
200         int i;
201
202         DBG(" -> smp_init_cell()\n");
203
204         smp_ops = &bpa_iic_smp_ops;
205
206         /* Mark threads which are still spinning in hold loops. */
207         if (cpu_has_feature(CPU_FTR_SMT)) {
208                 for_each_present_cpu(i) {
209                         if (i % 2 == 0)
210                                 /*
211                                  * Even-numbered logical cpus correspond to
212                                  * primary threads.
213                                  */
214                                 cpu_set(i, of_spin_map);
215                 }
216         } else {
217                 of_spin_map = cpu_present_map;
218         }
219
220         cpu_clear(boot_cpuid, of_spin_map);
221
222         /* Non-lpar has additional take/give timebase */
223         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
224                 smp_ops->give_timebase = cell_give_timebase;
225                 smp_ops->take_timebase = cell_take_timebase;
226         }
227
228         DBG(" <- smp_init_cell()\n");
229 }