powerpc: 32-bit CHRP SMP fixes
[linux-2.6.git] / arch / powerpc / platforms / chrp / smp.c
1 /*
2  * Smp support for CHRP machines.
3  *
4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
5  * deal of code from the sparc and intel versions.
6  *
7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
8  *
9  */
10
11 #include <linux/config.h>
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/smp.h>
15 #include <linux/smp_lock.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/delay.h>
19 #include <linux/init.h>
20 #include <linux/spinlock.h>
21
22 #include <asm/ptrace.h>
23 #include <asm/atomic.h>
24 #include <asm/irq.h>
25 #include <asm/page.h>
26 #include <asm/pgtable.h>
27 #include <asm/sections.h>
28 #include <asm/io.h>
29 #include <asm/prom.h>
30 #include <asm/smp.h>
31 #include <asm/residual.h>
32 #include <asm/time.h>
33 #include <asm/open_pic.h>
34 #include <asm/machdep.h>
35 #include <asm/smp.h>
36 #include <asm/mpic.h>
37
38 extern unsigned long smp_chrp_cpu_nr;
39
40 static int __init smp_chrp_probe(void)
41 {
42         struct device_node *cpus = NULL;
43         unsigned int *reg;
44         int reglen;
45         int ncpus = 0;
46         int cpuid;
47         unsigned int phys;
48
49         /* Count CPUs in the device-tree */
50         cpuid = 1;      /* the boot cpu is logical cpu 0 */
51         while ((cpus = of_find_node_by_type(cpus, "cpu")) != NULL) {
52                 phys = ncpus;
53                 reg = (unsigned int *) get_property(cpus, "reg", &reglen);
54                 if (reg && reglen >= sizeof(unsigned int))
55                         /* hmmm, not having a reg property would be bad */
56                         phys = *reg;
57                 if (phys != boot_cpuid_phys) {
58                         set_hard_smp_processor_id(cpuid, phys);
59                         ++cpuid;
60                 }
61                 ++ncpus;
62         }
63
64         printk(KERN_INFO "CHRP SMP probe found %d cpus\n", ncpus);
65
66         /* Nothing more to do if less than 2 of them */
67         if (ncpus <= 1)
68                 return 1;
69
70         mpic_request_ipis();
71
72         return ncpus;
73 }
74
75 static void __devinit smp_chrp_kick_cpu(int nr)
76 {
77         *(unsigned long *)KERNELBASE = nr;
78         asm volatile("dcbf 0,%0"::"r"(KERNELBASE):"memory");
79 }
80
81 static void __devinit smp_chrp_setup_cpu(int cpu_nr)
82 {
83         mpic_setup_this_cpu();
84 }
85
86 static DEFINE_SPINLOCK(timebase_lock);
87 static unsigned int timebase_upper = 0, timebase_lower = 0;
88
89 void __devinit smp_chrp_give_timebase(void)
90 {
91         spin_lock(&timebase_lock);
92         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
93         timebase_upper = get_tbu();
94         timebase_lower = get_tbl();
95         spin_unlock(&timebase_lock);
96
97         while (timebase_upper || timebase_lower)
98                 barrier();
99         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
100 }
101
102 void __devinit smp_chrp_take_timebase(void)
103 {
104         while (!(timebase_upper || timebase_lower))
105                 barrier();
106         spin_lock(&timebase_lock);
107         set_tb(timebase_upper, timebase_lower);
108         timebase_upper = 0;
109         timebase_lower = 0;
110         spin_unlock(&timebase_lock);
111         printk("CPU %i taken timebase\n", smp_processor_id());
112 }
113
114 /* CHRP with openpic */
115 struct smp_ops_t chrp_smp_ops = {
116         .message_pass = smp_mpic_message_pass,
117         .probe = smp_chrp_probe,
118         .kick_cpu = smp_chrp_kick_cpu,
119         .setup_cpu = smp_chrp_setup_cpu,
120         .give_timebase = smp_chrp_give_timebase,
121         .take_timebase = smp_chrp_take_timebase,
122 };