xref: /openbmc/linux/arch/arm/kernel/psci_smp.c (revision b34e08d5)
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License version 2 as
4  * published by the Free Software Foundation.
5  *
6  * This program is distributed in the hope that it will be useful,
7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9  * GNU General Public License for more details.
10  *
11  * Copyright (C) 2012 ARM Limited
12  *
13  * Author: Will Deacon <will.deacon@arm.com>
14  */
15 
16 #include <linux/init.h>
17 #include <linux/smp.h>
18 #include <linux/of.h>
19 
20 #include <asm/psci.h>
21 #include <asm/smp_plat.h>
22 
23 /*
24  * psci_smp assumes that the following is true about PSCI:
25  *
26  * cpu_suspend   Suspend the execution on a CPU
27  * @state        we don't currently describe affinity levels, so just pass 0.
28  * @entry_point  the first instruction to be executed on return
29  * returns 0  success, < 0 on failure
30  *
31  * cpu_off       Power down a CPU
32  * @state        we don't currently describe affinity levels, so just pass 0.
33  * no return on successful call
34  *
35  * cpu_on        Power up a CPU
36  * @cpuid        cpuid of target CPU, as from MPIDR
37  * @entry_point  the first instruction to be executed on return
38  * returns 0  success, < 0 on failure
39  *
40  * migrate       Migrate the context to a different CPU
41  * @cpuid        cpuid of target CPU, as from MPIDR
42  * returns 0  success, < 0 on failure
43  *
44  */
45 
46 extern void secondary_startup(void);
47 
48 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
49 {
50 	if (psci_ops.cpu_on)
51 		return psci_ops.cpu_on(cpu_logical_map(cpu),
52 				       __pa(secondary_startup));
53 	return -ENODEV;
54 }
55 
56 #ifdef CONFIG_HOTPLUG_CPU
57 void __ref psci_cpu_die(unsigned int cpu)
58 {
59        const struct psci_power_state ps = {
60                .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
61        };
62 
63        if (psci_ops.cpu_off)
64                psci_ops.cpu_off(ps);
65 
66        /* We should never return */
67        panic("psci: cpu %d failed to shutdown\n", cpu);
68 }
69 #endif
70 
71 bool __init psci_smp_available(void)
72 {
73 	/* is cpu_on available at least? */
74 	return (psci_ops.cpu_on != NULL);
75 }
76 
77 struct smp_operations __initdata psci_smp_ops = {
78 	.smp_boot_secondary	= psci_boot_secondary,
79 #ifdef CONFIG_HOTPLUG_CPU
80 	.cpu_die		= psci_cpu_die,
81 #endif
82 };
83