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