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 const struct cpu_operations *ops = get_cpu_ops(cpu); 22 int ret = -EOPNOTSUPP; 23 24 if (ops && ops->cpu_suspend && ops->cpu_init_idle) 25 ret = ops->cpu_init_idle(cpu); 26 27 return ret; 28 } 29 30 /** 31 * arm_cpuidle_suspend() - function to enter a low-power idle state 32 * @index: 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 const struct cpu_operations *ops = get_cpu_ops(cpu); 41 42 return ops->cpu_suspend(index); 43 } 44 45 #ifdef CONFIG_ACPI 46 47 #include <acpi/processor.h> 48 49 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags)) 50 51 static int psci_acpi_cpu_init_idle(unsigned int cpu) 52 { 53 int i, count; 54 struct acpi_lpi_state *lpi; 55 struct acpi_processor *pr = per_cpu(processors, cpu); 56 57 /* 58 * If the PSCI cpu_suspend function hook has not been initialized 59 * idle states must not be enabled, so bail out 60 */ 61 if (!psci_ops.cpu_suspend) 62 return -EOPNOTSUPP; 63 64 if (unlikely(!pr || !pr->flags.has_lpi)) 65 return -EINVAL; 66 67 count = pr->power.count - 1; 68 if (count <= 0) 69 return -ENODEV; 70 71 for (i = 0; i < count; i++) { 72 u32 state; 73 74 lpi = &pr->power.lpi_states[i + 1]; 75 /* 76 * Only bits[31:0] represent a PSCI power_state while 77 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification 78 */ 79 state = lpi->address; 80 if (!psci_power_state_is_valid(state)) { 81 pr_warn("Invalid PSCI power state %#x\n", state); 82 return -EINVAL; 83 } 84 } 85 86 return 0; 87 } 88 89 int acpi_processor_ffh_lpi_probe(unsigned int cpu) 90 { 91 return psci_acpi_cpu_init_idle(cpu); 92 } 93 94 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) 95 { 96 u32 state = lpi->address; 97 98 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags)) 99 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter, 100 lpi->index, state); 101 else 102 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, 103 lpi->index, state); 104 } 105 #endif 106