1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/module.h>
4 #include <linux/init.h>
5 #include <linux/kernel.h>
6 #include <linux/mm.h>
7 #include <linux/sched.h>
8 #include <linux/kernel_stat.h>
9 #include <linux/notifier.h>
10 #include <linux/cpu.h>
11 #include <linux/percpu.h>
12 #include <linux/delay.h>
13 #include <linux/err.h>
14 #include <linux/irq.h>
15 #include <linux/irq_work.h>
16 #include <linux/irqdomain.h>
17 #include <linux/of.h>
18 #include <linux/seq_file.h>
19 #include <linux/sched/task_stack.h>
20 #include <linux/sched/mm.h>
21 #include <linux/sched/hotplug.h>
22 #include <asm/irq.h>
23 #include <asm/traps.h>
24 #include <asm/sections.h>
25 #include <asm/mmu_context.h>
26 #ifdef CONFIG_CPU_HAS_FPU
27 #include <abi/fpu.h>
28 #endif
29
30 enum ipi_message_type {
31 IPI_EMPTY,
32 IPI_RESCHEDULE,
33 IPI_CALL_FUNC,
34 IPI_IRQ_WORK,
35 IPI_MAX
36 };
37
38 struct ipi_data_struct {
39 unsigned long bits ____cacheline_aligned;
40 unsigned long stats[IPI_MAX] ____cacheline_aligned;
41 };
42 static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data);
43
44 static irqreturn_t handle_ipi(int irq, void *dev)
45 {
46 unsigned long *stats = this_cpu_ptr(&ipi_data)->stats;
47
48 while (true) {
49 unsigned long ops;
50
51 ops = xchg(&this_cpu_ptr(&ipi_data)->bits, 0);
52 if (ops == 0)
53 return IRQ_HANDLED;
54
55 if (ops & (1 << IPI_RESCHEDULE)) {
56 stats[IPI_RESCHEDULE]++;
57 scheduler_ipi();
58 }
59
60 if (ops & (1 << IPI_CALL_FUNC)) {
61 stats[IPI_CALL_FUNC]++;
62 generic_smp_call_function_interrupt();
63 }
64
65 if (ops & (1 << IPI_IRQ_WORK)) {
66 stats[IPI_IRQ_WORK]++;
67 irq_work_run();
68 }
69
70 BUG_ON((ops >> IPI_MAX) != 0);
71 }
72
73 return IRQ_HANDLED;
74 }
75
76 static void (*send_arch_ipi)(const struct cpumask *mask);
77
78 static int ipi_irq;
79 void __init set_send_ipi(void (*func)(const struct cpumask *mask), int irq)
80 {
81 if (send_arch_ipi)
82 return;
83
84 send_arch_ipi = func;
85 ipi_irq = irq;
86 }
87
88 static void
89 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
90 {
91 int i;
92
93 for_each_cpu(i, to_whom)
94 set_bit(operation, &per_cpu_ptr(&ipi_data, i)->bits);
95
96 smp_mb();
97 send_arch_ipi(to_whom);
98 }
99
100 static const char * const ipi_names[] = {
101 [IPI_EMPTY] = "Empty interrupts",
102 [IPI_RESCHEDULE] = "Rescheduling interrupts",
103 [IPI_CALL_FUNC] = "Function call interrupts",
104 [IPI_IRQ_WORK] = "Irq work interrupts",
105 };
106
107 int arch_show_interrupts(struct seq_file *p, int prec)
108 {
109 unsigned int cpu, i;
110
111 for (i = 0; i < IPI_MAX; i++) {
112 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
113 prec >= 4 ? " " : "");
114 for_each_online_cpu(cpu)
115 seq_printf(p, "%10lu ",
116 per_cpu_ptr(&ipi_data, cpu)->stats[i]);
117 seq_printf(p, " %s\n", ipi_names[i]);
118 }
119
120 return 0;
121 }
122
123 void arch_send_call_function_ipi_mask(struct cpumask *mask)
124 {
125 send_ipi_message(mask, IPI_CALL_FUNC);
126 }
127
128 void arch_send_call_function_single_ipi(int cpu)
129 {
130 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
131 }
132
133 static void ipi_stop(void *unused)
134 {
135 while (1);
136 }
137
138 void smp_send_stop(void)
139 {
140 on_each_cpu(ipi_stop, NULL, 1);
141 }
142
143 void arch_smp_send_reschedule(int cpu)
144 {
145 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
146 }
147
148 #ifdef CONFIG_IRQ_WORK
149 void arch_irq_work_raise(void)
150 {
151 send_ipi_message(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
152 }
153 #endif
154
155 void __init smp_prepare_cpus(unsigned int max_cpus)
156 {
157 }
158
159 static int ipi_dummy_dev;
160
161 void __init setup_smp_ipi(void)
162 {
163 int rc;
164
165 if (ipi_irq == 0)
166 return;
167
168 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt",
169 &ipi_dummy_dev);
170 if (rc)
171 panic("%s IRQ request failed\n", __func__);
172
173 enable_percpu_irq(ipi_irq, 0);
174 }
175
176 void __init setup_smp(void)
177 {
178 struct device_node *node = NULL;
179 unsigned int cpu;
180
181 for_each_of_cpu_node(node) {
182 if (!of_device_is_available(node))
183 continue;
184
185 cpu = of_get_cpu_hwid(node, 0);
186 if (cpu >= NR_CPUS)
187 continue;
188
189 set_cpu_possible(cpu, true);
190 set_cpu_present(cpu, true);
191 }
192 }
193
194 extern void _start_smp_secondary(void);
195
196 volatile unsigned int secondary_hint;
197 volatile unsigned int secondary_hint2;
198 volatile unsigned int secondary_ccr;
199 volatile unsigned int secondary_stack;
200 volatile unsigned int secondary_msa1;
201 volatile unsigned int secondary_pgd;
202
203 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
204 {
205 unsigned long mask = 1 << cpu;
206
207 secondary_stack =
208 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8;
209 secondary_hint = mfcr("cr31");
210 secondary_hint2 = mfcr("cr<21, 1>");
211 secondary_ccr = mfcr("cr18");
212 secondary_msa1 = read_mmu_msa1();
213 secondary_pgd = mfcr("cr<29, 15>");
214
215 /*
216 * Because other CPUs are in reset status, we must flush data
217 * from cache to out and secondary CPUs use them in
218 * csky_start_secondary(void)
219 */
220 mtcr("cr17", 0x22);
221
222 if (mask & mfcr("cr<29, 0>")) {
223 send_arch_ipi(cpumask_of(cpu));
224 } else {
225 /* Enable cpu in SMP reset ctrl reg */
226 mask |= mfcr("cr<29, 0>");
227 mtcr("cr<29, 0>", mask);
228 }
229
230 /* Wait for the cpu online */
231 while (!cpu_online(cpu));
232
233 secondary_stack = 0;
234
235 return 0;
236 }
237
238 void __init smp_cpus_done(unsigned int max_cpus)
239 {
240 }
241
242 void csky_start_secondary(void)
243 {
244 struct mm_struct *mm = &init_mm;
245 unsigned int cpu = smp_processor_id();
246
247 mtcr("cr31", secondary_hint);
248 mtcr("cr<21, 1>", secondary_hint2);
249 mtcr("cr18", secondary_ccr);
250
251 mtcr("vbr", vec_base);
252
253 flush_tlb_all();
254 write_mmu_pagemask(0);
255
256 #ifdef CONFIG_CPU_HAS_FPU
257 init_fpu();
258 #endif
259
260 enable_percpu_irq(ipi_irq, 0);
261
262 mmget(mm);
263 mmgrab(mm);
264 current->active_mm = mm;
265 cpumask_set_cpu(cpu, mm_cpumask(mm));
266
267 notify_cpu_starting(cpu);
268 set_cpu_online(cpu, true);
269
270 pr_info("CPU%u Online: %s...\n", cpu, __func__);
271
272 local_irq_enable();
273 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
274 }
275
276 #ifdef CONFIG_HOTPLUG_CPU
277 int __cpu_disable(void)
278 {
279 unsigned int cpu = smp_processor_id();
280
281 set_cpu_online(cpu, false);
282
283 irq_migrate_all_off_this_cpu();
284
285 clear_tasks_mm_cpumask(cpu);
286
287 return 0;
288 }
289
290 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
291 {
292 pr_notice("CPU%u: shutdown\n", cpu);
293 }
294
295 void __noreturn arch_cpu_idle_dead(void)
296 {
297 idle_task_exit();
298
299 cpuhp_ap_report_dead();
300
301 while (!secondary_stack)
302 arch_cpu_idle();
303
304 raw_local_irq_disable();
305
306 asm volatile(
307 "mov sp, %0\n"
308 "mov r8, %0\n"
309 "jmpi csky_start_secondary"
310 :
311 : "r" (secondary_stack));
312
313 BUG();
314 }
315 #endif
316
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