4408518eaebe4afe76d6a1b3f354a4a6cc0a0421
[linux-2.6.git] / arch / powerpc / platforms / pseries / smp.c
1 /*
2  * SMP support for pSeries 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 "xics.h"
42 #include <asm/cputable.h>
43 #include <asm/firmware.h>
44 #include <asm/system.h>
45 #include <asm/rtas.h>
46 #include <asm/pSeries_reconfig.h>
47 #include <asm/mpic.h>
48 #include <asm/vdso_datapage.h>
49
50 #include "plpar_wrappers.h"
51
52 #ifdef DEBUG
53 #include <asm/udbg.h>
54 #define DBG(fmt...) udbg_printf(fmt)
55 #else
56 #define DBG(fmt...)
57 #endif
58
59 /*
60  * The primary thread of each non-boot processor is recorded here before
61  * smp init.
62  */
63 static cpumask_t of_spin_map;
64
65 extern void generic_secondary_smp_init(unsigned long);
66
67 /**
68  * smp_startup_cpu() - start the given cpu
69  *
70  * At boot time, there is nothing to do for primary threads which were
71  * started from Open Firmware.  For anything else, call RTAS with the
72  * appropriate start location.
73  *
74  * Returns:
75  *      0       - failure
76  *      1       - success
77  */
78 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
79 {
80         int status;
81         unsigned long start_here = __pa((u32)*((unsigned long *)
82                                                generic_secondary_smp_init));
83         unsigned int pcpu;
84         int start_cpu;
85
86         if (cpu_isset(lcpu, of_spin_map))
87                 /* Already started by OF and sitting in spin loop */
88                 return 1;
89
90         pcpu = get_hard_smp_processor_id(lcpu);
91
92         /* Fixup atomic count: it exited inside IRQ handler. */
93         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
94
95         /* 
96          * If the RTAS start-cpu token does not exist then presume the
97          * cpu is already spinning.
98          */
99         start_cpu = rtas_token("start-cpu");
100         if (start_cpu == RTAS_UNKNOWN_SERVICE)
101                 return 1;
102
103         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
104         if (status != 0) {
105                 printk(KERN_ERR "start-cpu failed: %i\n", status);
106                 return 0;
107         }
108
109         return 1;
110 }
111
112 #ifdef CONFIG_XICS
113 static inline void smp_xics_do_message(int cpu, int msg)
114 {
115         set_bit(msg, &xics_ipi_message[cpu].value);
116         mb();
117         xics_cause_IPI(cpu);
118 }
119
120 static void smp_xics_message_pass(int target, int msg)
121 {
122         unsigned int i;
123
124         if (target < NR_CPUS) {
125                 smp_xics_do_message(target, msg);
126         } else {
127                 for_each_online_cpu(i) {
128                         if (target == MSG_ALL_BUT_SELF
129                             && i == smp_processor_id())
130                                 continue;
131                         smp_xics_do_message(i, msg);
132                 }
133         }
134 }
135
136 static int __init smp_xics_probe(void)
137 {
138         xics_request_IPIs();
139
140         return cpus_weight(cpu_possible_map);
141 }
142
143 static void __devinit smp_xics_setup_cpu(int cpu)
144 {
145         if (cpu != boot_cpuid)
146                 xics_setup_cpu();
147
148         if (firmware_has_feature(FW_FEATURE_SPLPAR))
149                 vpa_init(cpu);
150
151         cpu_clear(cpu, of_spin_map);
152
153 }
154 #endif /* CONFIG_XICS */
155
156 static DEFINE_SPINLOCK(timebase_lock);
157 static unsigned long timebase = 0;
158
159 static void __devinit pSeries_give_timebase(void)
160 {
161         spin_lock(&timebase_lock);
162         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
163         timebase = get_tb();
164         spin_unlock(&timebase_lock);
165
166         while (timebase)
167                 barrier();
168         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
169 }
170
171 static void __devinit pSeries_take_timebase(void)
172 {
173         while (!timebase)
174                 barrier();
175         spin_lock(&timebase_lock);
176         set_tb(timebase >> 32, timebase & 0xffffffff);
177         timebase = 0;
178         spin_unlock(&timebase_lock);
179 }
180
181 static void __devinit smp_pSeries_kick_cpu(int nr)
182 {
183         BUG_ON(nr < 0 || nr >= NR_CPUS);
184
185         if (!smp_startup_cpu(nr))
186                 return;
187
188         /*
189          * The processor is currently spinning, waiting for the
190          * cpu_start field to become non-zero After we set cpu_start,
191          * the processor will continue on to secondary_start
192          */
193         paca[nr].cpu_start = 1;
194 }
195
196 static int smp_pSeries_cpu_bootable(unsigned int nr)
197 {
198         /* Special case - we inhibit secondary thread startup
199          * during boot if the user requests it.  Odd-numbered
200          * cpus are assumed to be secondary threads.
201          */
202         if (system_state < SYSTEM_RUNNING &&
203             cpu_has_feature(CPU_FTR_SMT) &&
204             !smt_enabled_at_boot && nr % 2 != 0)
205                 return 0;
206
207         return 1;
208 }
209 #ifdef CONFIG_MPIC
210 static struct smp_ops_t pSeries_mpic_smp_ops = {
211         .message_pass   = smp_mpic_message_pass,
212         .probe          = smp_mpic_probe,
213         .kick_cpu       = smp_pSeries_kick_cpu,
214         .setup_cpu      = smp_mpic_setup_cpu,
215 };
216 #endif
217 #ifdef CONFIG_XICS
218 static struct smp_ops_t pSeries_xics_smp_ops = {
219         .message_pass   = smp_xics_message_pass,
220         .probe          = smp_xics_probe,
221         .kick_cpu       = smp_pSeries_kick_cpu,
222         .setup_cpu      = smp_xics_setup_cpu,
223         .cpu_bootable   = smp_pSeries_cpu_bootable,
224 };
225 #endif
226
227 /* This is called very early */
228 static void __init smp_init_pseries(void)
229 {
230         int i;
231
232         DBG(" -> smp_init_pSeries()\n");
233
234         /* Mark threads which are still spinning in hold loops. */
235         if (cpu_has_feature(CPU_FTR_SMT)) {
236                 for_each_present_cpu(i) { 
237                         if (i % 2 == 0)
238                                 /*
239                                  * Even-numbered logical cpus correspond to
240                                  * primary threads.
241                                  */
242                                 cpu_set(i, of_spin_map);
243                 }
244         } else {
245                 of_spin_map = cpu_present_map;
246         }
247
248         cpu_clear(boot_cpuid, of_spin_map);
249
250         /* Non-lpar has additional take/give timebase */
251         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
252                 smp_ops->give_timebase = pSeries_give_timebase;
253                 smp_ops->take_timebase = pSeries_take_timebase;
254         }
255
256         DBG(" <- smp_init_pSeries()\n");
257 }
258
259 #ifdef CONFIG_MPIC
260 void __init smp_init_pseries_mpic(void)
261 {
262         smp_ops = &pSeries_mpic_smp_ops;
263
264         smp_init_pseries();
265 }
266 #endif
267
268 void __init smp_init_pseries_xics(void)
269 {
270         smp_ops = &pSeries_xics_smp_ops;
271
272         smp_init_pseries();
273 }