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
handle_ipi(int irq,void * dev)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;
set_send_ipi(void (* func)(const struct cpumask * mask),int 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
send_ipi_message(const struct cpumask * to_whom,enum ipi_message_type operation)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
arch_show_interrupts(struct seq_file * p,int prec)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
arch_send_call_function_ipi_mask(struct cpumask * mask)123 void arch_send_call_function_ipi_mask(struct cpumask *mask)
124 {
125 send_ipi_message(mask, IPI_CALL_FUNC);
126 }
127
arch_send_call_function_single_ipi(int cpu)128 void arch_send_call_function_single_ipi(int cpu)
129 {
130 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
131 }
132
ipi_stop(void * unused)133 static void ipi_stop(void *unused)
134 {
135 while (1);
136 }
137
smp_send_stop(void)138 void smp_send_stop(void)
139 {
140 on_each_cpu(ipi_stop, NULL, 1);
141 }
142
arch_smp_send_reschedule(int cpu)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
arch_irq_work_raise(void)149 void arch_irq_work_raise(void)
150 {
151 send_ipi_message(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
152 }
153 #endif
154
smp_prepare_boot_cpu(void)155 void __init smp_prepare_boot_cpu(void)
156 {
157 }
158
smp_prepare_cpus(unsigned int max_cpus)159 void __init smp_prepare_cpus(unsigned int max_cpus)
160 {
161 }
162
163 static int ipi_dummy_dev;
164
setup_smp_ipi(void)165 void __init setup_smp_ipi(void)
166 {
167 int rc;
168
169 if (ipi_irq == 0)
170 return;
171
172 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt",
173 &ipi_dummy_dev);
174 if (rc)
175 panic("%s IRQ request failed\n", __func__);
176
177 enable_percpu_irq(ipi_irq, 0);
178 }
179
setup_smp(void)180 void __init setup_smp(void)
181 {
182 struct device_node *node = NULL;
183 unsigned int cpu;
184
185 for_each_of_cpu_node(node) {
186 if (!of_device_is_available(node))
187 continue;
188
189 cpu = of_get_cpu_hwid(node, 0);
190 if (cpu >= NR_CPUS)
191 continue;
192
193 set_cpu_possible(cpu, true);
194 set_cpu_present(cpu, true);
195 }
196 }
197
198 extern void _start_smp_secondary(void);
199
200 volatile unsigned int secondary_hint;
201 volatile unsigned int secondary_hint2;
202 volatile unsigned int secondary_ccr;
203 volatile unsigned int secondary_stack;
204 volatile unsigned int secondary_msa1;
205 volatile unsigned int secondary_pgd;
206
__cpu_up(unsigned int cpu,struct task_struct * tidle)207 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
208 {
209 unsigned long mask = 1 << cpu;
210
211 secondary_stack =
212 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8;
213 secondary_hint = mfcr("cr31");
214 secondary_hint2 = mfcr("cr<21, 1>");
215 secondary_ccr = mfcr("cr18");
216 secondary_msa1 = read_mmu_msa1();
217 secondary_pgd = mfcr("cr<29, 15>");
218
219 /*
220 * Because other CPUs are in reset status, we must flush data
221 * from cache to out and secondary CPUs use them in
222 * csky_start_secondary(void)
223 */
224 mtcr("cr17", 0x22);
225
226 if (mask & mfcr("cr<29, 0>")) {
227 send_arch_ipi(cpumask_of(cpu));
228 } else {
229 /* Enable cpu in SMP reset ctrl reg */
230 mask |= mfcr("cr<29, 0>");
231 mtcr("cr<29, 0>", mask);
232 }
233
234 /* Wait for the cpu online */
235 while (!cpu_online(cpu));
236
237 secondary_stack = 0;
238
239 return 0;
240 }
241
smp_cpus_done(unsigned int max_cpus)242 void __init smp_cpus_done(unsigned int max_cpus)
243 {
244 }
245
csky_start_secondary(void)246 void csky_start_secondary(void)
247 {
248 struct mm_struct *mm = &init_mm;
249 unsigned int cpu = smp_processor_id();
250
251 mtcr("cr31", secondary_hint);
252 mtcr("cr<21, 1>", secondary_hint2);
253 mtcr("cr18", secondary_ccr);
254
255 mtcr("vbr", vec_base);
256
257 flush_tlb_all();
258 write_mmu_pagemask(0);
259
260 #ifdef CONFIG_CPU_HAS_FPU
261 init_fpu();
262 #endif
263
264 enable_percpu_irq(ipi_irq, 0);
265
266 mmget(mm);
267 mmgrab(mm);
268 current->active_mm = mm;
269 cpumask_set_cpu(cpu, mm_cpumask(mm));
270
271 notify_cpu_starting(cpu);
272 set_cpu_online(cpu, true);
273
274 pr_info("CPU%u Online: %s...\n", cpu, __func__);
275
276 local_irq_enable();
277 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
278 }
279
280 #ifdef CONFIG_HOTPLUG_CPU
__cpu_disable(void)281 int __cpu_disable(void)
282 {
283 unsigned int cpu = smp_processor_id();
284
285 set_cpu_online(cpu, false);
286
287 irq_migrate_all_off_this_cpu();
288
289 clear_tasks_mm_cpumask(cpu);
290
291 return 0;
292 }
293
arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)294 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
295 {
296 pr_notice("CPU%u: shutdown\n", cpu);
297 }
298
arch_cpu_idle_dead(void)299 void __noreturn arch_cpu_idle_dead(void)
300 {
301 idle_task_exit();
302
303 cpuhp_ap_report_dead();
304
305 while (!secondary_stack)
306 arch_cpu_idle();
307
308 raw_local_irq_disable();
309
310 asm volatile(
311 "mov sp, %0\n"
312 "mov r8, %0\n"
313 "jmpi csky_start_secondary"
314 :
315 : "r" (secondary_stack));
316
317 BUG();
318 }
319 #endif
320
