drivers/acpi/processor_pdc.c

   1 /*
   2  * Copyright (C) 2005 Intel Corporation
   3  * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
   4  *
   5  *      Alex Chiang <achiang@hp.com>
   6  *      - Unified x86/ia64 implementations
   7  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   8  *      - Added _PDC for platforms with Intel CPUs
   9  */
  10 #include <linux/dmi.h>
  11
  12 #include <acpi/acpi_drivers.h>
  13 #include <acpi/processor.h>
  14
  15 #include "internal.h"
  16
  17 #define PREFIX                  "ACPI: "
  18 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  19 ACPI_MODULE_NAME("processor_pdc");
  20
  21 static int set_no_mwait(const struct dmi_system_id *id)
  22 {
  23         printk(KERN_NOTICE PREFIX "%s detected - "
  24                 "disabling mwait for CPU C-states\n", id->ident);
  25         idle_nomwait = 1;
  26         return 0;
  27 }
  28
  29 static struct dmi_system_id __cpuinitdata processor_idle_dmi_table[] = {
  30         {
  31         set_no_mwait, "IFL91 board", {
  32         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
  33         DMI_MATCH(DMI_SYS_VENDOR, "ZEPTO"),
  34         DMI_MATCH(DMI_PRODUCT_VERSION, "3215W"),
  35         DMI_MATCH(DMI_BOARD_NAME, "IFL91") }, NULL},
  36         {
  37         set_no_mwait, "Extensa 5220", {
  38         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
  39         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
  40         DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
  41         DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
  42         {},
  43 };
  44
  45 static void acpi_set_pdc_bits(u32 *buf)
  46 {
  47         buf[0] = ACPI_PDC_REVISION_ID;
  48         buf[1] = 1;
  49
  50         /* Enable coordination with firmware's _TSD info */
  51         buf[2] = ACPI_PDC_SMP_T_SWCOORD;
  52
  53         /* Twiddle arch-specific bits needed for _PDC */
  54         arch_acpi_set_pdc_bits(buf);
  55 }
  56
  57 static struct acpi_object_list *acpi_processor_alloc_pdc(void)
  58 {
  59         struct acpi_object_list *obj_list;
  60         union acpi_object *obj;
  61         u32 *buf;
  62
  63         /* allocate and initialize pdc. It will be used later. */
  64         obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
  65         if (!obj_list) {
  66                 printk(KERN_ERR "Memory allocation error\n");
  67                 return NULL;
  68         }
  69
  70         obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
  71         if (!obj) {
  72                 printk(KERN_ERR "Memory allocation error\n");
  73                 kfree(obj_list);
  74                 return NULL;
  75         }
  76
  77         buf = kmalloc(12, GFP_KERNEL);
  78         if (!buf) {
  79                 printk(KERN_ERR "Memory allocation error\n");
  80                 kfree(obj);
  81                 kfree(obj_list);
  82                 return NULL;
  83         }
  84
  85         acpi_set_pdc_bits(buf);
  86
  87         obj->type = ACPI_TYPE_BUFFER;
  88         obj->buffer.length = 12;
  89         obj->buffer.pointer = (u8 *) buf;
  90         obj_list->count = 1;
  91         obj_list->pointer = obj;
  92
  93         return obj_list;
  94 }
  95
  96 /*
  97  * _PDC is required for a BIOS-OS handshake for most of the newer
  98  * ACPI processor features.
  99  */
 100 static int
 101 acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
 102 {
 103         acpi_status status = AE_OK;
 104
 105         if (idle_nomwait) {
 106                 /*
 107                  * If mwait is disabled for CPU C-states, the C2C3_FFH access
 108                  * mode will be disabled in the parameter of _PDC object.
 109                  * Of course C1_FFH access mode will also be disabled.
 110                  */
 111                 union acpi_object *obj;
 112                 u32 *buffer = NULL;
 113
 114                 obj = pdc_in->pointer;
 115                 buffer = (u32 *)(obj->buffer.pointer);
 116                 buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
 117
 118         }
 119         status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
 120
 121         if (ACPI_FAILURE(status))
 122                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 123                     "Could not evaluate _PDC, using legacy perf. control.\n"));
 124
 125         return status;
 126 }
 127
 128 void acpi_processor_set_pdc(acpi_handle handle)
 129 {
 130         struct acpi_object_list *obj_list;
 131
 132         if (arch_has_acpi_pdc() == false)
 133                 return;
 134
 135         obj_list = acpi_processor_alloc_pdc();
 136         if (!obj_list)
 137                 return;
 138
 139         acpi_processor_eval_pdc(handle, obj_list);
 140
 141         kfree(obj_list->pointer->buffer.pointer);
 142         kfree(obj_list->pointer);
 143         kfree(obj_list);
 144 }
 145 EXPORT_SYMBOL_GPL(acpi_processor_set_pdc);
 146
 147 static acpi_status
 148 early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
 149 {
 150         acpi_processor_set_pdc(handle);
 151         return AE_OK;
 152 }
 153
 154 void acpi_early_processor_set_pdc(void)
 155 {
 156         /*
 157          * Check whether the system is DMI table. If yes, OSPM
 158          * should not use mwait for CPU-states.
 159          */
 160         dmi_check_system(processor_idle_dmi_table);
 161
 162         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 163                             ACPI_UINT32_MAX,
 164                             early_init_pdc, NULL, NULL, NULL);
 165 }