drivers/acpi/processor_pdc.c

   1 /*
   2  * Copyright (C) 2005 Intel Corporation
   3  * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
   4  *
   5  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   6  *      - Added _PDC for platforms with Intel CPUs
   7  */
   8
   9 #define pr_fmt(fmt) "ACPI: " fmt
  10
  11 #include <linux/dmi.h>
  12 #include <linux/slab.h>
  13 #include <linux/acpi.h>
  14 #include <acpi/processor.h>
  15
  16 #include "internal.h"
  17
  18 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  19 ACPI_MODULE_NAME("processor_pdc");
  20
  21 static bool __init processor_physically_present(acpi_handle handle)
  22 {
  23         int cpuid, type;
  24         u32 acpi_id;
  25         acpi_status status;
  26         acpi_object_type acpi_type;
  27         unsigned long long tmp;
  28         union acpi_object object = { 0 };
  29         struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
  30
  31         status = acpi_get_type(handle, &acpi_type);
  32         if (ACPI_FAILURE(status))
  33                 return false;
  34
  35         switch (acpi_type) {
  36         case ACPI_TYPE_PROCESSOR:
  37                 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
  38                 if (ACPI_FAILURE(status))
  39                         return false;
  40                 acpi_id = object.processor.proc_id;
  41                 break;
  42         case ACPI_TYPE_DEVICE:
  43                 status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
  44                 if (ACPI_FAILURE(status))
  45                         return false;
  46                 acpi_id = tmp;
  47                 break;
  48         default:
  49                 return false;
  50         }
  51
  52         type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
  53         cpuid = acpi_get_cpuid(handle, type, acpi_id);
  54
  55         if (cpuid == -1)
  56                 return false;
  57
  58         return true;
  59 }
  60
  61 static void acpi_set_pdc_bits(u32 *buf)
  62 {
  63         buf[0] = ACPI_PDC_REVISION_ID;
  64         buf[1] = 1;
  65
  66         /* Enable coordination with firmware's _TSD info */
  67         buf[2] = ACPI_PDC_SMP_T_SWCOORD;
  68
  69         /* Twiddle arch-specific bits needed for _PDC */
  70         arch_acpi_set_pdc_bits(buf);
  71 }
  72
  73 static struct acpi_object_list *acpi_processor_alloc_pdc(void)
  74 {
  75         struct acpi_object_list *obj_list;
  76         union acpi_object *obj;
  77         u32 *buf;
  78
  79         /* allocate and initialize pdc. It will be used later. */
  80         obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
  81         if (!obj_list)
  82                 goto out;
  83
  84         obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
  85         if (!obj) {
  86                 kfree(obj_list);
  87                 goto out;
  88         }
  89
  90         buf = kmalloc(12, GFP_KERNEL);
  91         if (!buf) {
  92                 kfree(obj);
  93                 kfree(obj_list);
  94                 goto out;
  95         }
  96
  97         acpi_set_pdc_bits(buf);
  98
  99         obj->type = ACPI_TYPE_BUFFER;
 100         obj->buffer.length = 12;
 101         obj->buffer.pointer = (u8 *) buf;
 102         obj_list->count = 1;
 103         obj_list->pointer = obj;
 104
 105         return obj_list;
 106 out:
 107         pr_err("Memory allocation error\n");
 108         return NULL;
 109 }
 110
 111 /*
 112  * _PDC is required for a BIOS-OS handshake for most of the newer
 113  * ACPI processor features.
 114  */
 115 static acpi_status
 116 acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
 117 {
 118         acpi_status status = AE_OK;
 119
 120         if (boot_option_idle_override == IDLE_NOMWAIT) {
 121                 /*
 122                  * If mwait is disabled for CPU C-states, the C2C3_FFH access
 123                  * mode will be disabled in the parameter of _PDC object.
 124                  * Of course C1_FFH access mode will also be disabled.
 125                  */
 126                 union acpi_object *obj;
 127                 u32 *buffer = NULL;
 128
 129                 obj = pdc_in->pointer;
 130                 buffer = (u32 *)(obj->buffer.pointer);
 131                 buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
 132
 133         }
 134         status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
 135
 136         if (ACPI_FAILURE(status))
 137                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 138                     "Could not evaluate _PDC, using legacy perf. control.\n"));
 139
 140         return status;
 141 }
 142
 143 void acpi_processor_set_pdc(acpi_handle handle)
 144 {
 145         struct acpi_object_list *obj_list;
 146
 147         if (arch_has_acpi_pdc() == false)
 148                 return;
 149
 150         obj_list = acpi_processor_alloc_pdc();
 151         if (!obj_list)
 152                 return;
 153
 154         acpi_processor_eval_pdc(handle, obj_list);
 155
 156         kfree(obj_list->pointer->buffer.pointer);
 157         kfree(obj_list->pointer);
 158         kfree(obj_list);
 159 }
 160
 161 static acpi_status __init
 162 early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
 163 {
 164         if (processor_physically_present(handle) == false)
 165                 return AE_OK;
 166
 167         acpi_processor_set_pdc(handle);
 168         return AE_OK;
 169 }
 170
 171 static int __init set_no_mwait(const struct dmi_system_id *id)
 172 {
 173         pr_notice("%s detected - disabling mwait for CPU C-states\n",
 174                   id->ident);
 175         boot_option_idle_override = IDLE_NOMWAIT;
 176         return 0;
 177 }
 178
 179 static struct dmi_system_id processor_idle_dmi_table[] __initdata = {
 180         {
 181         set_no_mwait, "Extensa 5220", {
 182         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
 183         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 184         DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
 185         DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
 186         {},
 187 };
 188
 189 static void __init processor_dmi_check(void)
 190 {
 191         /*
 192          * Check whether the system is DMI table. If yes, OSPM
 193          * should not use mwait for CPU-states.
 194          */
 195         dmi_check_system(processor_idle_dmi_table);
 196 }
 197
 198 void __init acpi_early_processor_set_pdc(void)
 199 {
 200         processor_dmi_check();
 201
 202         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 203                             ACPI_UINT32_MAX,
 204                             early_init_pdc, NULL, NULL, NULL);
 205         acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, early_init_pdc, NULL, NULL);
 206 }