1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ARM64 CPU idle arch support 4 * 5 * Copyright (C) 2014 ARM Ltd. 6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> 7 */ 8 9 #include <linux/acpi.h> 10 #include <linux/cpuidle.h> 11 #include <linux/cpu_pm.h> 12 #include <linux/of.h> 13 #include <linux/of_device.h> 14 #include <linux/psci.h> 15 16 #include <asm/cpuidle.h> 17 #include <asm/cpu_ops.h> 18 19 int arm_cpuidle_init(unsigned int cpu) 20 { 21 int ret = -EOPNOTSUPP; 22 23 if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_suspend && 24 cpu_ops[cpu]->cpu_init_idle) 25 ret = cpu_ops[cpu]->cpu_init_idle(cpu); 26 27 return ret; 28 } 29 30 /** 31 * arm_cpuidle_suspend() - function to enter a low-power idle state 32 * @arg: argument to pass to CPU suspend operations 33 * 34 * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU 35 * operations back-end error code otherwise. 36 */ 37 int arm_cpuidle_suspend(int index) 38 { 39 int cpu = smp_processor_id(); 40 41 return cpu_ops[cpu]->cpu_suspend(index); 42 } 43 44 #ifdef CONFIG_ACPI 45 46 #include <acpi/processor.h> 47 48 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags)) 49 50 static int psci_acpi_cpu_init_idle(unsigned int cpu) 51 { 52 int i, count; 53 struct acpi_lpi_state *lpi; 54 struct acpi_processor *pr = per_cpu(processors, cpu); 55 56 /* 57 * If the PSCI cpu_suspend function hook has not been initialized 58 * idle states must not be enabled, so bail out 59 */ 60 if (!psci_ops.cpu_suspend) 61 return -EOPNOTSUPP; 62 63 if (unlikely(!pr || !pr->flags.has_lpi)) 64 return -EINVAL; 65 66 count = pr->power.count - 1; 67 if (count <= 0) 68 return -ENODEV; 69 70 for (i = 0; i < count; i++) { 71 u32 state; 72 73 lpi = &pr->power.lpi_states[i + 1]; 74 /* 75 * Only bits[31:0] represent a PSCI power_state while 76 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification 77 */ 78 state = lpi->address; 79 if (!psci_power_state_is_valid(state)) { 80 pr_warn("Invalid PSCI power state %#x\n", state); 81 return -EINVAL; 82 } 83 } 84 85 return 0; 86 } 87 88 int acpi_processor_ffh_lpi_probe(unsigned int cpu) 89 { 90 return psci_acpi_cpu_init_idle(cpu); 91 } 92 93 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) 94 { 95 u32 state = lpi->address; 96 97 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags)) 98 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter, 99 lpi->index, state); 100 else 101 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, 102 lpi->index, state); 103 } 104 #endif 105