drivers/acpi/arm64/cpuidle.c

   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 }