arch/i386/kernel/acpi/cstate.c

   1 /*
   2  * arch/i386/kernel/acpi/cstate.c
   3  *
   4  * Copyright (C) 2005 Intel Corporation
   5  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   6  *      - Added _PDC for SMP C-states on Intel CPUs
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/acpi.h>
  13
  14 #include <acpi/processor.h>
  15 #include <asm/acpi.h>
  16
  17 static void acpi_processor_power_init_intel_pdc(struct acpi_processor_power
  18                                                 *pow)
  19 {
  20         struct acpi_object_list *obj_list;
  21         union acpi_object *obj;
  22         u32 *buf;
  23
  24         /* allocate and initialize pdc. It will be used later. */
  25         obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
  26         if (!obj_list) {
  27                 printk(KERN_ERR "Memory allocation error\n");
  28                 return;
  29         }
  30
  31         obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
  32         if (!obj) {
  33                 printk(KERN_ERR "Memory allocation error\n");
  34                 kfree(obj_list);
  35                 return;
  36         }
  37
  38         buf = kmalloc(12, GFP_KERNEL);
  39         if (!buf) {
  40                 printk(KERN_ERR "Memory allocation error\n");
  41                 kfree(obj);
  42                 kfree(obj_list);
  43                 return;
  44         }
  45
  46         buf[0] = ACPI_PDC_REVISION_ID;
  47         buf[1] = 1;
  48         buf[2] = ACPI_PDC_C_CAPABILITY_SMP;
  49
  50         obj->type = ACPI_TYPE_BUFFER;
  51         obj->buffer.length = 12;
  52         obj->buffer.pointer = (u8 *) buf;
  53         obj_list->count = 1;
  54         obj_list->pointer = obj;
  55         pow->pdc = obj_list;
  56
  57         return;
  58 }
  59
  60 /* Initialize _PDC data based on the CPU vendor */
  61 void acpi_processor_power_init_pdc(struct acpi_processor_power *pow,
  62                                    unsigned int cpu)
  63 {
  64         struct cpuinfo_x86 *c = cpu_data + cpu;
  65
  66         pow->pdc = NULL;
  67         if (c->x86_vendor == X86_VENDOR_INTEL)
  68                 acpi_processor_power_init_intel_pdc(pow);
  69
  70         return;
  71 }
  72
  73 EXPORT_SYMBOL(acpi_processor_power_init_pdc);
  74
  75 /*
  76  * Initialize bm_flags based on the CPU cache properties
  77  * On SMP it depends on cache configuration
  78  * - When cache is not shared among all CPUs, we flush cache
  79  *   before entering C3.
  80  * - When cache is shared among all CPUs, we use bm_check
  81  *   mechanism as in UP case
  82  *
  83  * This routine is called only after all the CPUs are online
  84  */
  85 void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
  86                                         unsigned int cpu)
  87 {
  88         struct cpuinfo_x86 *c = cpu_data + cpu;
  89
  90         flags->bm_check = 0;
  91         if (num_online_cpus() == 1)
  92                 flags->bm_check = 1;
  93         else if (c->x86_vendor == X86_VENDOR_INTEL) {
  94                 /*
  95                  * Today all CPUs that support C3 share cache.
  96                  * TBD: This needs to look at cache shared map, once
  97                  * multi-core detection patch makes to the base.
  98                  */
  99                 flags->bm_check = 1;
 100         }
 101 }
 102
 103 EXPORT_SYMBOL(acpi_processor_power_init_bm_check);