summaryrefslogtreecommitdiffstats
path: root/arch/hexagon/kernel/smp.c
blob: 619c56420aa0c750ba6226791a89e49d33d3d5fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
// SPDX-License-Identifier: GPL-2.0-only
/*
 * SMP support for Hexagon
 *
 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
 */

#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/sched/mm.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/mm_types.h>

#include <asm/time.h>    /*  timer_interrupt  */
#include <asm/hexagon_vm.h>

#define BASE_IPI_IRQ 26

/*
 * cpu_possible_mask needs to be filled out prior to setup_per_cpu_areas
 * (which is prior to any of our smp_prepare_cpu crap), in order to set
 * up the...  per_cpu areas.
 */

struct ipi_data {
	unsigned long bits;
};

static DEFINE_PER_CPU(struct ipi_data, ipi_data);

static inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi,
				int cpu)
{
	unsigned long msg = 0;
	do {
		msg = find_next_bit(ops, BITS_PER_LONG, msg+1);

		switch (msg) {

		case IPI_TIMER:
			ipi_timer();
			break;

		case IPI_CALL_FUNC:
			generic_smp_call_function_interrupt();
			break;

		case IPI_CPU_STOP:
			/*
			 * call vmstop()
			 */
			__vmstop();
			break;

		case IPI_RESCHEDULE:
			scheduler_ipi();
			break;
		}
	} while (msg < BITS_PER_LONG);
}

/*  Used for IPI call from other CPU's to unmask int  */
void smp_vm_unmask_irq(void *info)
{
	__vmintop_locen((long) info);
}


/*
 * This is based on Alpha's IPI stuff.
 * Supposed to take (int, void*) as args now.
 * Specifically, first arg is irq, second is the irq_desc.
 */

irqreturn_t handle_ipi(int irq, void *desc)
{
	int cpu = smp_processor_id();
	struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
	unsigned long ops;

	while ((ops = xchg(&ipi->bits, 0)) != 0)
		__handle_ipi(&ops, ipi, cpu);
	return IRQ_HANDLED;
}

void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
{
	unsigned long flags;
	unsigned long cpu;
	unsigned long retval;

	local_irq_save(flags);

	for_each_cpu(cpu, cpumask) {
		struct ipi_data *ipi = &per_cpu(ipi_data, cpu);

		set_bit(msg, &ipi->bits);
		/*  Possible barrier here  */
		retval = __vmintop_post(BASE_IPI_IRQ+cpu);

		if (retval != 0) {
			printk(KERN_ERR "interrupt %ld not configured?\n",
				BASE_IPI_IRQ+cpu);
		}
	}

	local_irq_restore(flags);
}

void __init smp_prepare_boot_cpu(void)
{
}

/*
 * interrupts should already be disabled from the VM
 * SP should already be correct; need to set THREADINFO_REG
 * to point to current thread info
 */

void start_secondary(void)
{
	unsigned long thread_ptr;
	unsigned int cpu, irq;

	/*  Calculate thread_info pointer from stack pointer  */
	__asm__ __volatile__(
		"%0 = SP;\n"
		: "=r" (thread_ptr)
	);

	thread_ptr = thread_ptr & ~(THREAD_SIZE-1);

	__asm__ __volatile__(
		QUOTED_THREADINFO_REG " = %0;\n"
		:
		: "r" (thread_ptr)
	);

	/*  Set the memory struct  */
	mmgrab(&init_mm);
	current->active_mm = &init_mm;

	cpu = smp_processor_id();

	irq = BASE_IPI_IRQ + cpu;
	if (request_irq(irq, handle_ipi, IRQF_TRIGGER_RISING, "ipi_handler",
			NULL))
		pr_err("Failed to request irq %u (ipi_handler)\n", irq);

	/*  Register the clock_event dummy  */
	setup_percpu_clockdev();

	printk(KERN_INFO "%s cpu %d\n", __func__, current_thread_info()->cpu);

	notify_cpu_starting(cpu);

	set_cpu_online(cpu, true);

	local_irq_enable();

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}


/*
 * called once for each present cpu
 * apparently starts up the CPU and then
 * maintains control until "cpu_online(cpu)" is set.
 */

int __cpu_up(unsigned int cpu, struct task_struct *idle)
{
	struct thread_info *thread = (struct thread_info *)idle->stack;
	void *stack_start;

	thread->cpu = cpu;

	/*  Boot to the head.  */
	stack_start =  ((void *) thread) + THREAD_SIZE;
	__vmstart(start_secondary, stack_start);

	while (!cpu_online(cpu))
		barrier();

	return 0;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
	int i, irq = BASE_IPI_IRQ;

	/*
	 * should eventually have some sort of machine
	 * descriptor that has this stuff
	 */

	/*  Right now, let's just fake it. */
	for (i = 0; i < max_cpus; i++)
		set_cpu_present(i, true);

	/*  Also need to register the interrupts for IPI  */
	if (max_cpus > 1) {
		if (request_irq(irq, handle_ipi, IRQF_TRIGGER_RISING,
				"ipi_handler", NULL))
			pr_err("Failed to request irq %d (ipi_handler)\n", irq);
	}
}

void smp_send_reschedule(int cpu)
{
	send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
}

void smp_send_stop(void)
{
	struct cpumask targets;
	cpumask_copy(&targets, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), &targets);
	send_ipi(&targets, IPI_CPU_STOP);
}

void arch_send_call_function_single_ipi(int cpu)
{
	send_ipi(cpumask_of(cpu), IPI_CALL_FUNC);
}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
	send_ipi(mask, IPI_CALL_FUNC);
}

int setup_profiling_timer(unsigned int multiplier)
{
	return -EINVAL;
}

void smp_start_cpus(void)
{
	int i;

	for (i = 0; i < NR_CPUS; i++)
		set_cpu_possible(i, true);
}