1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19#include <linux/acpi_pmtmr.h>
20#include <linux/clocksource.h>
21#include <linux/timex.h>
22#include <linux/errno.h>
23#include <linux/init.h>
24#include <linux/pci.h>
25#include <linux/delay.h>
26#include <asm/io.h>
27
28
29
30
31
32
33u32 pmtmr_ioport __read_mostly;
34
35static inline u32 read_pmtmr(void)
36{
37
38 return inl(pmtmr_ioport) & ACPI_PM_MASK;
39}
40
41u32 acpi_pm_read_verified(void)
42{
43 u32 v1 = 0, v2 = 0, v3 = 0;
44
45
46
47
48
49
50
51 do {
52 v1 = read_pmtmr();
53 v2 = read_pmtmr();
54 v3 = read_pmtmr();
55 } while (unlikely((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
56 || (v3 > v1 && v3 < v2)));
57
58 return v2;
59}
60
61static cycle_t acpi_pm_read(struct clocksource *cs)
62{
63 return (cycle_t)read_pmtmr();
64}
65
66static struct clocksource clocksource_acpi_pm = {
67 .name = "acpi_pm",
68 .rating = 200,
69 .read = acpi_pm_read,
70 .mask = (cycle_t)ACPI_PM_MASK,
71 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
72};
73
74
75#ifdef CONFIG_PCI
76static int acpi_pm_good;
77static int __init acpi_pm_good_setup(char *__str)
78{
79 acpi_pm_good = 1;
80 return 1;
81}
82__setup("acpi_pm_good", acpi_pm_good_setup);
83
84static cycle_t acpi_pm_read_slow(struct clocksource *cs)
85{
86 return (cycle_t)acpi_pm_read_verified();
87}
88
89static inline void acpi_pm_need_workaround(void)
90{
91 clocksource_acpi_pm.read = acpi_pm_read_slow;
92 clocksource_acpi_pm.rating = 120;
93}
94
95
96
97
98
99
100
101
102
103
104
105static void acpi_pm_check_blacklist(struct pci_dev *dev)
106{
107 if (acpi_pm_good)
108 return;
109
110
111 if (dev->revision < 3) {
112 printk(KERN_WARNING "* Found PM-Timer Bug on the chipset."
113 " Due to workarounds for a bug,\n"
114 "* this clock source is slow. Consider trying"
115 " other clock sources\n");
116
117 acpi_pm_need_workaround();
118 }
119}
120DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3,
121 acpi_pm_check_blacklist);
122
123static void acpi_pm_check_graylist(struct pci_dev *dev)
124{
125 if (acpi_pm_good)
126 return;
127
128 printk(KERN_WARNING "* The chipset may have PM-Timer Bug. Due to"
129 " workarounds for a bug,\n"
130 "* this clock source is slow. If you are sure your timer"
131 " does not have\n"
132 "* this bug, please use \"acpi_pm_good\" to disable the"
133 " workaround\n");
134
135 acpi_pm_need_workaround();
136}
137DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_0,
138 acpi_pm_check_graylist);
139DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_LE,
140 acpi_pm_check_graylist);
141#endif
142
143#ifndef CONFIG_X86_64
144#include <asm/mach_timer.h>
145#define PMTMR_EXPECTED_RATE \
146 ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (PIT_TICK_RATE>>10))
147
148
149
150
151static int verify_pmtmr_rate(void)
152{
153 cycle_t value1, value2;
154 unsigned long count, delta;
155
156 mach_prepare_counter();
157 value1 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
158 mach_countup(&count);
159 value2 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
160 delta = (value2 - value1) & ACPI_PM_MASK;
161
162
163 if (delta < (PMTMR_EXPECTED_RATE * 19) / 20 ||
164 delta > (PMTMR_EXPECTED_RATE * 21) / 20) {
165 printk(KERN_INFO "PM-Timer running at invalid rate: %lu%% "
166 "of normal - aborting.\n",
167 100UL * delta / PMTMR_EXPECTED_RATE);
168 return -1;
169 }
170
171 return 0;
172}
173#else
174#define verify_pmtmr_rate() (0)
175#endif
176
177
178#define ACPI_PM_MONOTONICITY_CHECKS 10
179
180#define ACPI_PM_READ_CHECKS 10000
181
182static int __init init_acpi_pm_clocksource(void)
183{
184 cycle_t value1, value2;
185 unsigned int i, j = 0;
186
187 if (!pmtmr_ioport)
188 return -ENODEV;
189
190
191 for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) {
192 udelay(100 * j);
193 value1 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
194 for (i = 0; i < ACPI_PM_READ_CHECKS; i++) {
195 value2 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
196 if (value2 == value1)
197 continue;
198 if (value2 > value1)
199 break;
200 if ((value2 < value1) && ((value2) < 0xFFF))
201 break;
202 printk(KERN_INFO "PM-Timer had inconsistent results:"
203 " %#llx, %#llx - aborting.\n",
204 value1, value2);
205 pmtmr_ioport = 0;
206 return -EINVAL;
207 }
208 if (i == ACPI_PM_READ_CHECKS) {
209 printk(KERN_INFO "PM-Timer failed consistency check "
210 " (%#llx) - aborting.\n", value1);
211 pmtmr_ioport = 0;
212 return -ENODEV;
213 }
214 }
215
216 if (verify_pmtmr_rate() != 0){
217 pmtmr_ioport = 0;
218 return -ENODEV;
219 }
220
221 return clocksource_register_hz(&clocksource_acpi_pm,
222 PMTMR_TICKS_PER_SEC);
223}
224
225
226
227
228fs_initcall(init_acpi_pm_clocksource);
229
230
231
232
233
234static int __init parse_pmtmr(char *arg)
235{
236 unsigned int base;
237 int ret;
238
239 ret = kstrtouint(arg, 16, &base);
240 if (ret)
241 return ret;
242
243 pr_info("PMTMR IOPort override: 0x%04x -> 0x%04x\n", pmtmr_ioport,
244 base);
245 pmtmr_ioport = base;
246
247 return 1;
248}
249__setup("pmtmr=", parse_pmtmr);
250