1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * sun4m SMP support.
4 *
5 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
6 */
7
8 #include <linux/clockchips.h>
9 #include <linux/interrupt.h>
10 #include <linux/profile.h>
11 #include <linux/delay.h>
12 #include <linux/sched/mm.h>
13 #include <linux/cpu.h>
14
15 #include <asm/cacheflush.h>
16 #include <asm/switch_to.h>
17 #include <asm/tlbflush.h>
18 #include <asm/timer.h>
19 #include <asm/oplib.h>
20
21 #include "irq.h"
22 #include "kernel.h"
23
24 #define IRQ_IPI_SINGLE 12
25 #define IRQ_IPI_MASK 13
26 #define IRQ_IPI_RESCHED 14
27 #define IRQ_CROSS_CALL 15
28
29 static inline unsigned long
30 swap_ulong(volatile unsigned long *ptr, unsigned long val)
31 {
32 __asm__ __volatile__("swap [%1], %0\n\t" :
33 "=&r" (val), "=&r" (ptr) :
34 "" (val), "1" (ptr));
35 return val;
36 }
37
38 void sun4m_cpu_pre_starting(void *arg)
39 {
40 }
41
42 void sun4m_cpu_pre_online(void *arg)
43 {
44 int cpuid = hard_smp_processor_id();
45
46 /* Allow master to continue. The master will then give us the
47 * go-ahead by setting the smp_commenced_mask and will wait without
48 * timeouts until our setup is completed fully (signified by
49 * our bit being set in the cpu_online_mask).
50 */
51 swap_ulong(&cpu_callin_map[cpuid], 1);
52
53 /* XXX: What's up with all the flushes? */
54 local_ops->cache_all();
55 local_ops->tlb_all();
56
57 /* Fix idle thread fields. */
58 __asm__ __volatile__("ld [%0], %%g6\n\t"
59 : : "r" (¤t_set[cpuid])
60 : "memory" /* paranoid */);
61
62 /* Attach to the address space of init_task. */
63 mmgrab(&init_mm);
64 current->active_mm = &init_mm;
65
66 while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
67 mb();
68 }
69
70 /*
71 * Cycle through the processors asking the PROM to start each one.
72 */
73 void __init smp4m_boot_cpus(void)
74 {
75 sun4m_unmask_profile_irq();
76 local_ops->cache_all();
77 }
78
79 int smp4m_boot_one_cpu(int i, struct task_struct *idle)
80 {
81 unsigned long *entry = &sun4m_cpu_startup;
82 int timeout;
83 int cpu_node;
84
85 cpu_find_by_mid(i, &cpu_node);
86 current_set[i] = task_thread_info(idle);
87
88 /* See trampoline.S for details... */
89 entry += ((i - 1) * 3);
90
91 /*
92 * Initialize the contexts table
93 * Since the call to prom_startcpu() trashes the structure,
94 * we need to re-initialize it for each cpu
95 */
96 smp_penguin_ctable.which_io = 0;
97 smp_penguin_ctable.phys_addr = (unsigned int) srmmu_ctx_table_phys;
98 smp_penguin_ctable.reg_size = 0;
99
100 /* whirrr, whirrr, whirrrrrrrrr... */
101 printk(KERN_INFO "Starting CPU %d at %p\n", i, entry);
102 local_ops->cache_all();
103 prom_startcpu(cpu_node, &smp_penguin_ctable, 0, (char *)entry);
104
105 /* wheee... it's going... */
106 for (timeout = 0; timeout < 10000; timeout++) {
107 if (cpu_callin_map[i])
108 break;
109 udelay(200);
110 }
111
112 if (!(cpu_callin_map[i])) {
113 printk(KERN_ERR "Processor %d is stuck.\n", i);
114 return -ENODEV;
115 }
116
117 local_ops->cache_all();
118 return 0;
119 }
120
121 void __init smp4m_smp_done(void)
122 {
123 int i, first;
124 int *prev;
125
126 /* setup cpu list for irq rotation */
127 first = 0;
128 prev = &first;
129 for_each_online_cpu(i) {
130 *prev = i;
131 prev = &cpu_data(i).next;
132 }
133 *prev = first;
134 local_ops->cache_all();
135
136 /* Ok, they are spinning and ready to go. */
137 }
138
139 static void sun4m_send_ipi(int cpu, int level)
140 {
141 sbus_writel(SUN4M_SOFT_INT(level), &sun4m_irq_percpu[cpu]->set);
142 }
143
144 static void sun4m_ipi_resched(int cpu)
145 {
146 sun4m_send_ipi(cpu, IRQ_IPI_RESCHED);
147 }
148
149 static void sun4m_ipi_single(int cpu)
150 {
151 sun4m_send_ipi(cpu, IRQ_IPI_SINGLE);
152 }
153
154 static void sun4m_ipi_mask_one(int cpu)
155 {
156 sun4m_send_ipi(cpu, IRQ_IPI_MASK);
157 }
158
159 static struct smp_funcall {
160 void *func;
161 unsigned long arg1;
162 unsigned long arg2;
163 unsigned long arg3;
164 unsigned long arg4;
165 unsigned long arg5;
166 unsigned long processors_in[SUN4M_NCPUS]; /* Set when ipi entered. */
167 unsigned long processors_out[SUN4M_NCPUS]; /* Set when ipi exited. */
168 } ccall_info;
169
170 static DEFINE_SPINLOCK(cross_call_lock);
171
172 /* Cross calls must be serialized, at least currently. */
173 static void sun4m_cross_call(void *func, cpumask_t mask, unsigned long arg1,
174 unsigned long arg2, unsigned long arg3,
175 unsigned long arg4)
176 {
177 register int ncpus = SUN4M_NCPUS;
178 unsigned long flags;
179
180 spin_lock_irqsave(&cross_call_lock, flags);
181
182 /* Init function glue. */
183 ccall_info.func = func;
184 ccall_info.arg1 = arg1;
185 ccall_info.arg2 = arg2;
186 ccall_info.arg3 = arg3;
187 ccall_info.arg4 = arg4;
188 ccall_info.arg5 = 0;
189
190 /* Init receive/complete mapping, plus fire the IPI's off. */
191 {
192 register int i;
193
194 cpumask_clear_cpu(smp_processor_id(), &mask);
195 cpumask_and(&mask, cpu_online_mask, &mask);
196 for (i = 0; i < ncpus; i++) {
197 if (cpumask_test_cpu(i, &mask)) {
198 ccall_info.processors_in[i] = 0;
199 ccall_info.processors_out[i] = 0;
200 sun4m_send_ipi(i, IRQ_CROSS_CALL);
201 } else {
202 ccall_info.processors_in[i] = 1;
203 ccall_info.processors_out[i] = 1;
204 }
205 }
206 }
207
208 {
209 register int i;
210
211 i = 0;
212 do {
213 if (!cpumask_test_cpu(i, &mask))
214 continue;
215 while (!ccall_info.processors_in[i])
216 barrier();
217 } while (++i < ncpus);
218
219 i = 0;
220 do {
221 if (!cpumask_test_cpu(i, &mask))
222 continue;
223 while (!ccall_info.processors_out[i])
224 barrier();
225 } while (++i < ncpus);
226 }
227 spin_unlock_irqrestore(&cross_call_lock, flags);
228 }
229
230 /* Running cross calls. */
231 void smp4m_cross_call_irq(void)
232 {
233 void (*func)(unsigned long, unsigned long, unsigned long, unsigned long,
234 unsigned long) = ccall_info.func;
235 int i = smp_processor_id();
236
237 ccall_info.processors_in[i] = 1;
238 func(ccall_info.arg1, ccall_info.arg2, ccall_info.arg3, ccall_info.arg4,
239 ccall_info.arg5);
240 ccall_info.processors_out[i] = 1;
241 }
242
243 void smp4m_percpu_timer_interrupt(struct pt_regs *regs)
244 {
245 struct pt_regs *old_regs;
246 struct clock_event_device *ce;
247 int cpu = smp_processor_id();
248
249 old_regs = set_irq_regs(regs);
250
251 ce = &per_cpu(sparc32_clockevent, cpu);
252
253 if (clockevent_state_periodic(ce))
254 sun4m_clear_profile_irq(cpu);
255 else
256 sparc_config.load_profile_irq(cpu, 0); /* Is this needless? */
257
258 irq_enter();
259 ce->event_handler(ce);
260 irq_exit();
261
262 set_irq_regs(old_regs);
263 }
264
265 static const struct sparc32_ipi_ops sun4m_ipi_ops = {
266 .cross_call = sun4m_cross_call,
267 .resched = sun4m_ipi_resched,
268 .single = sun4m_ipi_single,
269 .mask_one = sun4m_ipi_mask_one,
270 };
271
272 void __init sun4m_init_smp(void)
273 {
274 sparc32_ipi_ops = &sun4m_ipi_ops;
275 }
276
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