Merge tag 'csky-for-linus-4.21' of git://github.com/c-sky/csky-linux
[sfrench/cifs-2.6.git] / arch / csky / kernel / smp.c
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 = (unsigned int)tidle->stack + THREAD_SIZE - 8;
164         secondary_hint = mfcr("cr31");
165         secondary_ccr  = mfcr("cr18");
166
167         /*
168          * Because other CPUs are in reset status, we must flush data
169          * from cache to out and secondary CPUs use them in
170          * csky_start_secondary(void)
171          */
172         mtcr("cr17", 0x22);
173
174         if (mask & mfcr("cr<29, 0>")) {
175                 send_arch_ipi(cpumask_of(cpu));
176         } else {
177                 /* Enable cpu in SMP reset ctrl reg */
178                 mask |= mfcr("cr<29, 0>");
179                 mtcr("cr<29, 0>", mask);
180         }
181
182         /* Wait for the cpu online */
183         while (!cpu_online(cpu));
184
185         secondary_stack = 0;
186
187         return 0;
188 }
189
190 void __init smp_cpus_done(unsigned int max_cpus)
191 {
192 }
193
194 int setup_profiling_timer(unsigned int multiplier)
195 {
196         return -EINVAL;
197 }
198
199 void csky_start_secondary(void)
200 {
201         struct mm_struct *mm = &init_mm;
202         unsigned int cpu = smp_processor_id();
203
204         mtcr("cr31", secondary_hint);
205         mtcr("cr18", secondary_ccr);
206
207         mtcr("vbr", vec_base);
208
209         flush_tlb_all();
210         write_mmu_pagemask(0);
211         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);
212         TLBMISS_HANDLER_SETUP_PGD_KERNEL(swapper_pg_dir);
213
214         asid_cache(smp_processor_id()) = ASID_FIRST_VERSION;
215
216 #ifdef CONFIG_CPU_HAS_FPU
217         init_fpu();
218 #endif
219
220         enable_percpu_irq(ipi_irq, 0);
221
222         mmget(mm);
223         mmgrab(mm);
224         current->active_mm = mm;
225         cpumask_set_cpu(cpu, mm_cpumask(mm));
226
227         notify_cpu_starting(cpu);
228         set_cpu_online(cpu, true);
229
230         pr_info("CPU%u Online: %s...\n", cpu, __func__);
231
232         local_irq_enable();
233         preempt_disable();
234         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
235 }
236
237 #ifdef CONFIG_HOTPLUG_CPU
238 int __cpu_disable(void)
239 {
240         unsigned int cpu = smp_processor_id();
241
242         set_cpu_online(cpu, false);
243
244         irq_migrate_all_off_this_cpu();
245
246         clear_tasks_mm_cpumask(cpu);
247
248         return 0;
249 }
250
251 void __cpu_die(unsigned int cpu)
252 {
253         if (!cpu_wait_death(cpu, 5)) {
254                 pr_crit("CPU%u: shutdown failed\n", cpu);
255                 return;
256         }
257         pr_notice("CPU%u: shutdown\n", cpu);
258 }
259
260 void arch_cpu_idle_dead(void)
261 {
262         idle_task_exit();
263
264         cpu_report_death();
265
266         while (!secondary_stack)
267                 arch_cpu_idle();
268
269         local_irq_disable();
270
271         asm volatile(
272                 "mov    sp, %0\n"
273                 "mov    r8, %0\n"
274                 "jmpi   csky_start_secondary"
275                 :
276                 : "r" (secondary_stack));
277 }
278 #endif