root/drivers/acpi/processor_pdc.c

DEFINITIONS

1. processor_physically_present
2. acpi_set_pdc_bits
3. acpi_processor_alloc_pdc
4. acpi_processor_eval_pdc
5. acpi_processor_set_pdc
6. early_init_pdc
7. set_no_mwait
8. processor_dmi_check
9. acpi_early_processor_set_pdc

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2005 Intel Corporation
   4  * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
   5  *
   6  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   7  *      - Added _PDC for platforms with Intel CPUs
   8  */
   9 
  10 #define pr_fmt(fmt) "ACPI: " fmt
  11 
  12 #include <linux/dmi.h>
  13 #include <linux/slab.h>
  14 #include <linux/acpi.h>
  15 #include <acpi/processor.h>
  16 
  17 #include "internal.h"
  18 
  19 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  20 ACPI_MODULE_NAME("processor_pdc");
  21 
  22 static bool __init processor_physically_present(acpi_handle handle)
  23 {
  24         int cpuid, type;
  25         u32 acpi_id;
  26         acpi_status status;
  27         acpi_object_type acpi_type;
  28         unsigned long long tmp;
  29         union acpi_object object = { 0 };
  30         struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
  31 
  32         status = acpi_get_type(handle, &acpi_type);
  33         if (ACPI_FAILURE(status))
  34                 return false;
  35 
  36         switch (acpi_type) {
  37         case ACPI_TYPE_PROCESSOR:
  38                 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
  39                 if (ACPI_FAILURE(status))
  40                         return false;
  41                 acpi_id = object.processor.proc_id;
  42                 break;
  43         case ACPI_TYPE_DEVICE:
  44                 status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
  45                 if (ACPI_FAILURE(status))
  46                         return false;
  47                 acpi_id = tmp;
  48                 break;
  49         default:
  50                 return false;
  51         }
  52 
  53         type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
  54         cpuid = acpi_get_cpuid(handle, type, acpi_id);
  55 
  56         return !invalid_logical_cpuid(cpuid);
  57 }
  58 
  59 static void acpi_set_pdc_bits(u32 *buf)
  60 {
  61         buf[0] = ACPI_PDC_REVISION_ID;
  62         buf[1] = 1;
  63 
  64         /* Enable coordination with firmware's _TSD info */
  65         buf[2] = ACPI_PDC_SMP_T_SWCOORD;
  66 
  67         /* Twiddle arch-specific bits needed for _PDC */
  68         arch_acpi_set_pdc_bits(buf);
  69 }
  70 
  71 static struct acpi_object_list *acpi_processor_alloc_pdc(void)
  72 {
  73         struct acpi_object_list *obj_list;
  74         union acpi_object *obj;
  75         u32 *buf;
  76 
  77         /* allocate and initialize pdc. It will be used later. */
  78         obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
  79         if (!obj_list)
  80                 goto out;
  81 
  82         obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
  83         if (!obj) {
  84                 kfree(obj_list);
  85                 goto out;
  86         }
  87 
  88         buf = kmalloc(12, GFP_KERNEL);
  89         if (!buf) {
  90                 kfree(obj);
  91                 kfree(obj_list);
  92                 goto out;
  93         }
  94 
  95         acpi_set_pdc_bits(buf);
  96 
  97         obj->type = ACPI_TYPE_BUFFER;
  98         obj->buffer.length = 12;
  99         obj->buffer.pointer = (u8 *) buf;
 100         obj_list->count = 1;
 101         obj_list->pointer = obj;
 102 
 103         return obj_list;
 104 out:
 105         pr_err("Memory allocation error\n");
 106         return NULL;
 107 }
 108 
 109 /*
 110  * _PDC is required for a BIOS-OS handshake for most of the newer
 111  * ACPI processor features.
 112  */
 113 static acpi_status
 114 acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
 115 {
 116         acpi_status status = AE_OK;
 117 
 118         if (boot_option_idle_override == IDLE_NOMWAIT) {
 119                 /*
 120                  * If mwait is disabled for CPU C-states, the C2C3_FFH access
 121                  * mode will be disabled in the parameter of _PDC object.
 122                  * Of course C1_FFH access mode will also be disabled.
 123                  */
 124                 union acpi_object *obj;
 125                 u32 *buffer = NULL;
 126 
 127                 obj = pdc_in->pointer;
 128                 buffer = (u32 *)(obj->buffer.pointer);
 129                 buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
 130 
 131         }
 132         status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
 133 
 134         if (ACPI_FAILURE(status))
 135                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 136                     "Could not evaluate _PDC, using legacy perf. control.\n"));
 137 
 138         return status;
 139 }
 140 
 141 void acpi_processor_set_pdc(acpi_handle handle)
 142 {
 143         struct acpi_object_list *obj_list;
 144 
 145         if (arch_has_acpi_pdc() == false)
 146                 return;
 147 
 148         obj_list = acpi_processor_alloc_pdc();
 149         if (!obj_list)
 150                 return;
 151 
 152         acpi_processor_eval_pdc(handle, obj_list);
 153 
 154         kfree(obj_list->pointer->buffer.pointer);
 155         kfree(obj_list->pointer);
 156         kfree(obj_list);
 157 }
 158 
 159 static acpi_status __init
 160 early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
 161 {
 162         if (processor_physically_present(handle) == false)
 163                 return AE_OK;
 164 
 165         acpi_processor_set_pdc(handle);
 166         return AE_OK;
 167 }
 168 
 169 static int __init set_no_mwait(const struct dmi_system_id *id)
 170 {
 171         pr_notice("%s detected - disabling mwait for CPU C-states\n",
 172                   id->ident);
 173         boot_option_idle_override = IDLE_NOMWAIT;
 174         return 0;
 175 }
 176 
 177 static const struct dmi_system_id processor_idle_dmi_table[] __initconst = {
 178         {
 179         set_no_mwait, "Extensa 5220", {
 180         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
 181         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 182         DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
 183         DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
 184         {},
 185 };
 186 
 187 static void __init processor_dmi_check(void)
 188 {
 189         /*
 190          * Check whether the system is DMI table. If yes, OSPM
 191          * should not use mwait for CPU-states.
 192          */
 193         dmi_check_system(processor_idle_dmi_table);
 194 }
 195 
 196 void __init acpi_early_processor_set_pdc(void)
 197 {
 198         processor_dmi_check();
 199 
 200         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 201                             ACPI_UINT32_MAX,
 202                             early_init_pdc, NULL, NULL, NULL);
 203         acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, early_init_pdc, NULL, NULL);
 204 }