1/*
2 * Copyright (C) 2005 Intel Corporation
3 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
4 * - Added _PDC for SMP C-states on Intel CPUs
5 */
6
7#include <linux/kernel.h>
8#include <linux/export.h>
9#include <linux/init.h>
10#include <linux/acpi.h>
11#include <linux/cpu.h>
12#include <linux/sched.h>
13
14#include <acpi/processor.h>
15#include <asm/mwait.h>
16#include <asm/special_insns.h>
17
18/*
19 * Initialize bm_flags based on the CPU cache properties
20 * On SMP it depends on cache configuration
21 * - When cache is not shared among all CPUs, we flush cache
22 * before entering C3.
23 * - When cache is shared among all CPUs, we use bm_check
24 * mechanism as in UP case
25 *
26 * This routine is called only after all the CPUs are online
27 */
28void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
29 unsigned int cpu)
30{
31 struct cpuinfo_x86 *c = &cpu_data(cpu);
32
33 flags->bm_check = 0;
34 if (num_online_cpus() == 1)
35 flags->bm_check = 1;
36 else if (c->x86_vendor == X86_VENDOR_INTEL) {
37 /*
38 * Today all MP CPUs that support C3 share cache.
39 * And caches should not be flushed by software while
40 * entering C3 type state.
41 */
42 flags->bm_check = 1;
43 }
44
45 /*
46 * On all recent Intel platforms, ARB_DISABLE is a nop.
47 * So, set bm_control to zero to indicate that ARB_DISABLE
48 * is not required while entering C3 type state on
49 * P4, Core and beyond CPUs
50 */
51 if (c->x86_vendor == X86_VENDOR_INTEL &&
52 (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
53 flags->bm_control = 0;
54}
55EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
56
57/* The code below handles cstate entry with monitor-mwait pair on Intel*/
58
59struct cstate_entry {
60 struct {
61 unsigned int eax;
62 unsigned int ecx;
63 } states[ACPI_PROCESSOR_MAX_POWER];
64};
65static struct cstate_entry __percpu *cpu_cstate_entry; /* per CPU ptr */
66
67static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
68
69#define NATIVE_CSTATE_BEYOND_HALT (2)
70
71static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
72{
73 struct acpi_processor_cx *cx = _cx;
74 long retval;
75 unsigned int eax, ebx, ecx, edx;
76 unsigned int edx_part;
77 unsigned int cstate_type; /* C-state type and not ACPI C-state type */
78 unsigned int num_cstate_subtype;
79
80 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
81
82 /* Check whether this particular cx_type (in CST) is supported or not */
83 cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
84 MWAIT_CSTATE_MASK) + 1;
85 edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
86 num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
87
88 retval = 0;
89 /* If the HW does not support any sub-states in this C-state */
90 if (num_cstate_subtype == 0) {
91 pr_warn(FW_BUG "ACPI MWAIT C-state 0x%x not supported by HW (0x%x)\n",
92 cx->address, edx_part);
93 retval = -1;
94 goto out;
95 }
96
97 /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
98 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
99 !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
100 retval = -1;
101 goto out;
102 }
103
104 if (!mwait_supported[cstate_type]) {
105 mwait_supported[cstate_type] = 1;
106 printk(KERN_DEBUG
107 "Monitor-Mwait will be used to enter C-%d state\n",
108 cx->type);
109 }
110 snprintf(cx->desc,
111 ACPI_CX_DESC_LEN, "ACPI FFH MWAIT 0x%x",
112 cx->address);
113out:
114 return retval;
115}
116
117int acpi_processor_ffh_cstate_probe(unsigned int cpu,
118 struct acpi_processor_cx *cx, struct acpi_power_register *reg)
119{
120 struct cstate_entry *percpu_entry;
121 struct cpuinfo_x86 *c = &cpu_data(cpu);
122 long retval;
123
124 if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
125 return -1;
126
127 if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
128 return -1;
129
130 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
131 percpu_entry->states[cx->index].eax = 0;
132 percpu_entry->states[cx->index].ecx = 0;
133
134 /* Make sure we are running on right CPU */
135
136 retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);
137 if (retval == 0) {
138 /* Use the hint in CST */
139 percpu_entry->states[cx->index].eax = cx->address;
140 percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
141 }
142
143 /*
144 * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
145 * then we should skip checking BM_STS for this C-state.
146 * ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
147 */
148 if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
149 cx->bm_sts_skip = 1;
150
151 return retval;
152}
153EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
154
155void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
156{
157 unsigned int cpu = smp_processor_id();
158 struct cstate_entry *percpu_entry;
159
160 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
161 mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
162 percpu_entry->states[cx->index].ecx);
163}
164EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
165
166static int __init ffh_cstate_init(void)
167{
168 struct cpuinfo_x86 *c = &boot_cpu_data;
169
170 if (c->x86_vendor != X86_VENDOR_INTEL &&
171 c->x86_vendor != X86_VENDOR_AMD)
172 return -1;
173
174 cpu_cstate_entry = alloc_percpu(struct cstate_entry);
175 return 0;
176}
177
178static void __exit ffh_cstate_exit(void)
179{
180 free_percpu(cpu_cstate_entry);
181 cpu_cstate_entry = NULL;
182}
183
184arch_initcall(ffh_cstate_init);
185__exitcall(ffh_cstate_exit);
186