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/psci.h> 13 #include <acpi/processor.h> 14 15 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags)) 16 17 static int psci_acpi_cpu_init_idle(unsigned int cpu) 18 { 19 int i, count; 20 struct acpi_lpi_state *lpi; 21 struct acpi_processor *pr = per_cpu(processors, cpu); 22 23 if (unlikely(!pr || !pr->flags.has_lpi)) 24 return -EINVAL; 25 26 /* 27 * If the PSCI cpu_suspend function hook has not been initialized 28 * idle states must not be enabled, so bail out 29 */ 30 if (!psci_ops.cpu_suspend) 31 return -EOPNOTSUPP; 32 33 count = pr->power.count - 1; 34 if (count <= 0) 35 return -ENODEV; 36 37 for (i = 0; i < count; i++) { 38 u32 state; 39 40 lpi = &pr->power.lpi_states[i + 1]; 41 /* 42 * Only bits[31:0] represent a PSCI power_state while 43 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification 44 */ 45 state = lpi->address; 46 if (!psci_power_state_is_valid(state)) { 47 pr_warn("Invalid PSCI power state %#x\n", state); 48 return -EINVAL; 49 } 50 } 51 52 return 0; 53 } 54 55 int acpi_processor_ffh_lpi_probe(unsigned int cpu) 56 { 57 return psci_acpi_cpu_init_idle(cpu); 58 } 59 60 __cpuidle int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) 61 { 62 u32 state = lpi->address; 63 64 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags)) 65 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(psci_cpu_suspend_enter, 66 lpi->index, state); 67 else 68 return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter, 69 lpi->index, state); 70 } 71