2 * Copyright (C) 2005 Intel Corporation
3 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
5 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
6 * - Added _PDC for platforms with Intel CPUs
9 #define pr_fmt(fmt) "ACPI: " fmt
11 #include <linux/dmi.h>
12 #include <linux/slab.h>
13 #include <linux/acpi.h>
14 #include <acpi/processor.h>
18 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
19 ACPI_MODULE_NAME("processor_pdc");
21 static bool __init processor_physically_present(acpi_handle handle)
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 };
31 status = acpi_get_type(handle, &acpi_type);
32 if (ACPI_FAILURE(status))
36 case ACPI_TYPE_PROCESSOR:
37 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
38 if (ACPI_FAILURE(status))
40 acpi_id = object.processor.proc_id;
42 case ACPI_TYPE_DEVICE:
43 status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
44 if (ACPI_FAILURE(status))
52 type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
53 cpuid = acpi_get_cpuid(handle, type, acpi_id);
61 static void acpi_set_pdc_bits(u32 *buf)
63 buf[0] = ACPI_PDC_REVISION_ID;
66 /* Enable coordination with firmware's _TSD info */
67 buf[2] = ACPI_PDC_SMP_T_SWCOORD;
69 /* Twiddle arch-specific bits needed for _PDC */
70 arch_acpi_set_pdc_bits(buf);
73 static struct acpi_object_list *acpi_processor_alloc_pdc(void)
75 struct acpi_object_list *obj_list;
76 union acpi_object *obj;
79 /* allocate and initialize pdc. It will be used later. */
80 obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
84 obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
90 buf = kmalloc(12, GFP_KERNEL);
97 acpi_set_pdc_bits(buf);
99 obj->type = ACPI_TYPE_BUFFER;
100 obj->buffer.length = 12;
101 obj->buffer.pointer = (u8 *) buf;
103 obj_list->pointer = obj;
107 pr_err("Memory allocation error\n");
112 * _PDC is required for a BIOS-OS handshake for most of the newer
113 * ACPI processor features.
116 acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
118 acpi_status status = AE_OK;
120 if (boot_option_idle_override == IDLE_NOMWAIT) {
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.
126 union acpi_object *obj;
129 obj = pdc_in->pointer;
130 buffer = (u32 *)(obj->buffer.pointer);
131 buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
134 status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
136 if (ACPI_FAILURE(status))
137 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
138 "Could not evaluate _PDC, using legacy perf. control.\n"));
143 void acpi_processor_set_pdc(acpi_handle handle)
145 struct acpi_object_list *obj_list;
147 if (arch_has_acpi_pdc() == false)
150 obj_list = acpi_processor_alloc_pdc();
154 acpi_processor_eval_pdc(handle, obj_list);
156 kfree(obj_list->pointer->buffer.pointer);
157 kfree(obj_list->pointer);
161 static acpi_status __init
162 early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
164 if (processor_physically_present(handle) == false)
167 acpi_processor_set_pdc(handle);
171 static int __init set_no_mwait(const struct dmi_system_id *id)
173 pr_notice("%s detected - disabling mwait for CPU C-states\n",
175 boot_option_idle_override = IDLE_NOMWAIT;
179 static struct dmi_system_id processor_idle_dmi_table[] __initdata = {
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},
189 static void __init processor_dmi_check(void)
192 * Check whether the system is DMI table. If yes, OSPM
193 * should not use mwait for CPU-states.
195 dmi_check_system(processor_idle_dmi_table);
198 void __init acpi_early_processor_set_pdc(void)
200 processor_dmi_check();
202 acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
204 early_init_pdc, NULL, NULL, NULL);
205 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, early_init_pdc, NULL, NULL);