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/irqdomain.h>
16 #include <linux/of.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/sched/mm.h>
19 #include <linux/sched/hotplug.h>
20 #include <asm/irq.h>
21 #include <asm/traps.h>
22 #include <asm/sections.h>
23 #include <asm/mmu_context.h>
24 #include <asm/pgalloc.h>
25
26 struct ipi_data_struct {
27 unsigned long bits ____cacheline_aligned;
28 };
29 static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data);
30
31 enum ipi_message_type {
32 IPI_EMPTY,
33 IPI_RESCHEDULE,
34 IPI_CALL_FUNC,
35 IPI_MAX
36 };
37
38 static irqreturn_t handle_ipi(int irq, void *dev)
39 {
40 while (true) {
41 unsigned long ops;
42
43 ops = xchg(&this_cpu_ptr(&ipi_data)->bits, 0);
44 if (ops == 0)
45 return IRQ_HANDLED;
46
47 if (ops & (1 << IPI_RESCHEDULE))
48 scheduler_ipi();
49
50 if (ops & (1 << IPI_CALL_FUNC))
51 generic_smp_call_function_interrupt();
52
53 BUG_ON((ops >> IPI_MAX) != 0);
54 }
55
56 return IRQ_HANDLED;
57 }
58
59 static void (*send_arch_ipi)(const struct cpumask *mask);
60
61 static int ipi_irq;
62 void __init set_send_ipi(void (*func)(const struct cpumask *mask), int irq)
63 {
64 if (send_arch_ipi)
65 return;
66
67 send_arch_ipi = func;
68 ipi_irq = irq;
69 }
70
71 static void
72 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
73 {
74 int i;
75
76 for_each_cpu(i, to_whom)
77 set_bit(operation, &per_cpu_ptr(&ipi_data, i)->bits);
78
79 smp_mb();
80 send_arch_ipi(to_whom);
81 }
82
83 void arch_send_call_function_ipi_mask(struct cpumask *mask)
84 {
85 send_ipi_message(mask, IPI_CALL_FUNC);
86 }
87
88 void arch_send_call_function_single_ipi(int cpu)
89 {
90 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
91 }
92
93 static void ipi_stop(void *unused)
94 {
95 while (1);
96 }
97
98 void smp_send_stop(void)
99 {
100 on_each_cpu(ipi_stop, NULL, 1);
101 }
102
103 void smp_send_reschedule(int cpu)
104 {
105 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
106 }
107
108 void __init smp_prepare_boot_cpu(void)
109 {
110 }
111
112 void __init smp_prepare_cpus(unsigned int max_cpus)
113 {
114 }
115
116 static int ipi_dummy_dev;
117
118 void __init setup_smp_ipi(void)
119 {
120 int rc;
121
122 if (ipi_irq == 0)
123 panic("%s IRQ mapping failed\n", __func__);
124
125 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt",
126 &ipi_dummy_dev);
127 if (rc)
128 panic("%s IRQ request failed\n", __func__);
129
130 enable_percpu_irq(ipi_irq, 0);
131 }
132
133 void __init setup_smp(void)
134 {
135 struct device_node *node = NULL;
136 int cpu;
137
138 for_each_of_cpu_node(node) {
139 if (!of_device_is_available(node))
140 continue;
141
142 if (of_property_read_u32(node, "reg", &cpu))
143 continue;
144
145 if (cpu >= NR_CPUS)
146 continue;
147
148 set_cpu_possible(cpu, true);
149 set_cpu_present(cpu, true);
150 }
151 }
152
153 extern void _start_smp_secondary(void);
154
155 volatile unsigned int secondary_hint;
156 volatile unsigned int secondary_ccr;
157 volatile unsigned int secondary_stack;
158
159 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
160 {
161 unsigned long mask = 1 << cpu;
162
163 secondary_stack =
164 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8;
165 secondary_hint = mfcr("cr31");
166 secondary_ccr = mfcr("cr18");
167
168 /*
169 * Because other CPUs are in reset status, we must flush data
170 * from cache to out and secondary CPUs use them in
171 * csky_start_secondary(void)
172 */
173 mtcr("cr17", 0x22);
174
175 if (mask & mfcr("cr<29, 0>")) {
176 send_arch_ipi(cpumask_of(cpu));
177 } else {
178 /* Enable cpu in SMP reset ctrl reg */
179 mask |= mfcr("cr<29, 0>");
180 mtcr("cr<29, 0>", mask);
181 }
182
183 /* Wait for the cpu online */
184 while (!cpu_online(cpu));
185
186 secondary_stack = 0;
187
188 return 0;
189 }
190
191 void __init smp_cpus_done(unsigned int max_cpus)
192 {
193 }
194
195 int setup_profiling_timer(unsigned int multiplier)
196 {
197 return -EINVAL;
198 }
199
200 void csky_start_secondary(void)
201 {
202 struct mm_struct *mm = &init_mm;
203 unsigned int cpu = smp_processor_id();
204
205 mtcr("cr31", secondary_hint);
206 mtcr("cr18", secondary_ccr);
207
208 mtcr("vbr", vec_base);
209
210 flush_tlb_all();
211 write_mmu_pagemask(0);
212 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);
213 TLBMISS_HANDLER_SETUP_PGD_KERNEL(swapper_pg_dir);
214
215 asid_cache(smp_processor_id()) = ASID_FIRST_VERSION;
216
217 #ifdef CONFIG_CPU_HAS_FPU
218 init_fpu();
219 #endif
220
221 enable_percpu_irq(ipi_irq, 0);
222
223 mmget(mm);
224 mmgrab(mm);
225 current->active_mm = mm;
226 cpumask_set_cpu(cpu, mm_cpumask(mm));
227
228 notify_cpu_starting(cpu);
229 set_cpu_online(cpu, true);
230
231 pr_info("CPU%u Online: %s...\n", cpu, __func__);
232
233 local_irq_enable();
234 preempt_disable();
235 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
236 }
237
238 #ifdef CONFIG_HOTPLUG_CPU
239 int __cpu_disable(void)
240 {
241 unsigned int cpu = smp_processor_id();
242
243 set_cpu_online(cpu, false);
244
245 irq_migrate_all_off_this_cpu();
246
247 clear_tasks_mm_cpumask(cpu);
248
249 return 0;
250 }
251
252 void __cpu_die(unsigned int cpu)
253 {
254 if (!cpu_wait_death(cpu, 5)) {
255 pr_crit("CPU%u: shutdown failed\n", cpu);
256 return;
257 }
258 pr_notice("CPU%u: shutdown\n", cpu);
259 }
260
261 void arch_cpu_idle_dead(void)
262 {
263 idle_task_exit();
264
265 cpu_report_death();
266
267 while (!secondary_stack)
268 arch_cpu_idle();
269
270 local_irq_disable();
271
272 asm volatile(
273 "mov sp, %0\n"
274 "mov r8, %0\n"
275 "jmpi csky_start_secondary"
276 :
277 : "r" (secondary_stack));
278 }
279 #endif
280
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.