| 1 | |
| 2 | |
| 3 | *
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| 4 | * Copyright (C) 2013 ARM Limited
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| 5 | *
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| 6 | * Author: Will Deacon <[email protected]>
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| 7 |
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| 8 |
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| 9 | #define pr_fmt(fmt) "psci: " fmt
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| 10 |
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| 11 | #include <linux/init.h>
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| 12 | #include <linux/of.h>
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| 13 | #include <linux/smp.h>
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| 14 | #include <linux/delay.h>
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| 15 | #include <linux/psci.h>
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| 16 | #include <linux/mm.h>
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| 17 |
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| 18 | #include <uapi/linux/psci.h>
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| 19 |
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| 20 | #include <asm/cpu_ops.h>
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| 21 | #include <asm/errno.h>
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| 22 | #include <asm/smp_plat.h>
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| 23 |
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| 24 | static int __init cpu_psci_cpu_init(unsigned int cpu)
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| 25 | {
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| 26 | return 0;
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| 27 | }
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| 28 |
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| 29 | static int __init cpu_psci_cpu_prepare(unsigned int cpu)
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| 30 | {
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| 31 | if (!psci_ops.cpu_on) {
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| 32 | pr_err("no cpu_on method, not booting CPU%d\n", cpu);
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| 33 | return -ENODEV;
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| 34 | }
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| 35 |
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| 36 | return 0;
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| 37 | }
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| 38 |
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| 39 | static int cpu_psci_cpu_boot(unsigned int cpu)
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| 40 | {
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| 41 | phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
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| 42 | int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
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| 43 | if (err && err != -EPERM)
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| 44 | pr_err("failed to boot CPU%d (%d)\n", cpu, err);
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| 45 |
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| 46 | return err;
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| 47 | }
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| 48 |
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| 49 | #ifdef CONFIG_HOTPLUG_CPU
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| 50 | static bool cpu_psci_cpu_can_disable(unsigned int cpu)
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| 51 | {
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| 52 | return !psci_tos_resident_on(cpu);
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| 53 | }
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| 54 |
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| 55 | static int cpu_psci_cpu_disable(unsigned int cpu)
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| 56 | {
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| 57 |
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| 58 | if (!psci_ops.cpu_off)
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| 59 | return -EOPNOTSUPP;
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| 60 |
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| 61 |
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| 62 | if (psci_tos_resident_on(cpu))
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| 63 | return -EPERM;
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| 64 |
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| 65 | return 0;
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| 66 | }
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| 67 |
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| 68 | static void cpu_psci_cpu_die(unsigned int cpu)
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| 69 | {
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| 70 | |
| 71 | * There are no known implementations of PSCI actually using the
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| 72 | * power state field, pass a sensible default for now.
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| 73 |
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| 74 | u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
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| 75 | PSCI_0_2_POWER_STATE_TYPE_SHIFT;
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| 76 |
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| 77 | psci_ops.cpu_off(state);
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| 78 | }
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| 79 |
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| 80 | static int cpu_psci_cpu_kill(unsigned int cpu)
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| 81 | {
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| 82 | int err;
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| 83 | unsigned long start, end;
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| 84 |
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| 85 | if (!psci_ops.affinity_info)
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| 86 | return 0;
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| 87 | |
| 88 | * cpu_kill could race with cpu_die and we can
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| 89 | * potentially end up declaring this cpu undead
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| 90 | * while it is dying. So, try again a few times.
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| 91 |
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| 92 |
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| 93 | start = jiffies;
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| 94 | end = start + msecs_to_jiffies(100);
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| 95 | do {
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| 96 | err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
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| 97 | if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
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| 98 | pr_info("CPU%d killed (polled %d ms)\n", cpu,
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| 99 | jiffies_to_msecs(jiffies - start));
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| 100 | return 0;
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| 101 | }
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| 102 |
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| 103 | usleep_range(100, 1000);
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| 104 | } while (time_before(jiffies, end));
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| 105 |
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| 106 | pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
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| 107 | cpu, err);
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| 108 | return -ETIMEDOUT;
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| 109 | }
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| 110 | #endif
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| 111 |
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| 112 | const struct cpu_operations cpu_psci_ops = {
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| 113 | .name = "psci",
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| 114 | .cpu_init = cpu_psci_cpu_init,
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| 115 | .cpu_prepare = cpu_psci_cpu_prepare,
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| 116 | .cpu_boot = cpu_psci_cpu_boot,
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| 117 | #ifdef CONFIG_HOTPLUG_CPU
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| 118 | .cpu_can_disable = cpu_psci_cpu_can_disable,
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| 119 | .cpu_disable = cpu_psci_cpu_disable,
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| 120 | .cpu_die = cpu_psci_cpu_die,
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| 121 | .cpu_kill = cpu_psci_cpu_kill,
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| 122 | #endif
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| 123 | };
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| 124 |
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