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 #ifdef CONFIG_ACPI 17 18 #include <acpi/processor.h> 19 20 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags)) 21 22 static int psci_acpi_cpu_init_idle(unsigned int cpu) 23 { 24 int i, count; 25 struct acpi_lpi_state *lpi; 26 struct acpi_processor *pr = per_cpu(processors, cpu); 27 28 if (unlikely(!pr || !pr->flags.has_lpi)) 29 return -EINVAL; 30 31 /* 32 * If the PSCI cpu_suspend function hook has not been initialized 33 * idle states must not be enabled, so bail out 34 */ 35 if (!psci_ops.cpu_suspend) 36 return -EOPNOTSUPP; 37 38 count = pr->power.count - 1; 39 if (count <= 0) 40 return -ENODEV; 41 42 for (i = 0; i < count; i++) { 43 u32 state; 44 45 lpi = &pr->power.lpi_states[i + 1]; 46 /* 47 * Only bits[31:0] represent a PSCI power_state while 48 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification 49 */ 50 state = lpi->address; 51 if (!psci_power_state_is_valid(state)) { 52 pr_warn("Invalid PSCI power state %#x\n", state); 53 return -EINVAL; 54 } 55 } 56 57 return 0; 58 } 59 60 int acpi_processor_ffh_lpi_probe(unsigned int cpu) 61 { 62 return psci_acpi_cpu_init_idle(cpu); 63 } 64 65 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) 66 { 67 u32 state = lpi->address; 68 69 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags)) 70 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter, 71 lpi->index, state); 72 else 73 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter, 74 lpi->index, state); 75 } 76 #endif 77