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authorRafa� Bilski <rafalbilski@interia.pl>2007-02-05 13:57:25 -0500
committerDave Jones <davej@redhat.com>2007-02-10 20:01:47 -0500
commit86acd49aa128bd7a1d4362c256c21fbdc2d5b1a0 (patch)
treef3a70cd217c1b1db86b291b2b4a2e771850816aa
parent786f46b262cb7a491f4b144e42f076d5a1ef8eef (diff)
[CPUFREQ] Enhanced PowerSaver driver
This is driver for Enhanced Powersaver which is present in VIA C7 processors. Beta tested by Jorgen (jorgen (at) greven dot dk). Thanks! Based on documentation provided by Dave Jones (Thanks!) and C7 Eden datasheet available from www.via.com.tw. Looks like all these C7 Eden CPU's don't have P-states in BIOS. I know that 2 p-states is low, but Jorgen finds it usefull anyway because board is passive cooled. There are 3 different types of C7 processors (called brands): 0. C7-M - these processors can set any maultiplier between min and max, any voltage between min and max. 1. C7 - only min and max states are supported. Voltage is different for min and max states. 2. Eden - only min and max states are supported. Looks like this brand can only change multiplier. Voltage seems to be the same for min and max frequency. Signed-off-by: Rafal Bilski <rafalbilski@interia.pl> Signed-off-by: Dave Jones <davej@redhat.com>
-rw-r--r--arch/i386/kernel/cpu/cpufreq/Kconfig9
-rw-r--r--arch/i386/kernel/cpu/cpufreq/Makefile1
-rw-r--r--arch/i386/kernel/cpu/cpufreq/e_powersaver.c334
3 files changed, 344 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/Kconfig b/arch/i386/kernel/cpu/cpufreq/Kconfig
index 5299c5bf4454..6c52182ca323 100644
--- a/arch/i386/kernel/cpu/cpufreq/Kconfig
+++ b/arch/i386/kernel/cpu/cpufreq/Kconfig
@@ -217,6 +217,15 @@ config X86_LONGHAUL
217 217
218 If in doubt, say N. 218 If in doubt, say N.
219 219
220config X86_E_POWERSAVER
221 tristate "VIA C7 Enhanced PowerSaver (EXPERIMENTAL)"
222 select CPU_FREQ_TABLE
223 depends on EXPERIMENTAL
224 help
225 This adds the CPUFreq driver for VIA C7 processors.
226
227 If in doubt, say N.
228
220comment "shared options" 229comment "shared options"
221 230
222config X86_ACPI_CPUFREQ_PROC_INTF 231config X86_ACPI_CPUFREQ_PROC_INTF
diff --git a/arch/i386/kernel/cpu/cpufreq/Makefile b/arch/i386/kernel/cpu/cpufreq/Makefile
index 8de3abe322a9..560f7760dae5 100644
--- a/arch/i386/kernel/cpu/cpufreq/Makefile
+++ b/arch/i386/kernel/cpu/cpufreq/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_X86_POWERNOW_K6) += powernow-k6.o
2obj-$(CONFIG_X86_POWERNOW_K7) += powernow-k7.o 2obj-$(CONFIG_X86_POWERNOW_K7) += powernow-k7.o
3obj-$(CONFIG_X86_POWERNOW_K8) += powernow-k8.o 3obj-$(CONFIG_X86_POWERNOW_K8) += powernow-k8.o
4obj-$(CONFIG_X86_LONGHAUL) += longhaul.o 4obj-$(CONFIG_X86_LONGHAUL) += longhaul.o
5obj-$(CONFIG_X86_E_POWERSAVER) += e_powersaver.o
5obj-$(CONFIG_ELAN_CPUFREQ) += elanfreq.o 6obj-$(CONFIG_ELAN_CPUFREQ) += elanfreq.o
6obj-$(CONFIG_SC520_CPUFREQ) += sc520_freq.o 7obj-$(CONFIG_SC520_CPUFREQ) += sc520_freq.o
7obj-$(CONFIG_X86_LONGRUN) += longrun.o 8obj-$(CONFIG_X86_LONGRUN) += longrun.o
diff --git a/arch/i386/kernel/cpu/cpufreq/e_powersaver.c b/arch/i386/kernel/cpu/cpufreq/e_powersaver.c
new file mode 100644
index 000000000000..3243725f80ca
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/e_powersaver.c
@@ -0,0 +1,334 @@
1/*
2 * Based on documentation provided by Dave Jones. Thanks!
3 *
4 * Licensed under the terms of the GNU GPL License version 2.
5 *
6 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/cpufreq.h>
13#include <linux/ioport.h>
14#include <linux/slab.h>
15
16#include <asm/msr.h>
17#include <asm/tsc.h>
18#include <asm/timex.h>
19#include <asm/io.h>
20#include <asm/delay.h>
21
22#define EPS_BRAND_C7M 0
23#define EPS_BRAND_C7 1
24#define EPS_BRAND_EDEN 2
25#define EPS_BRAND_C3 3
26
27struct eps_cpu_data {
28 u32 fsb;
29 struct cpufreq_frequency_table freq_table[];
30};
31
32static struct eps_cpu_data *eps_cpu[NR_CPUS];
33
34
35static unsigned int eps_get(unsigned int cpu)
36{
37 struct eps_cpu_data *centaur;
38 u32 lo, hi;
39
40 if (cpu)
41 return 0;
42 centaur = eps_cpu[cpu];
43 if (centaur == NULL)
44 return 0;
45
46 /* Return current frequency */
47 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
48 return centaur->fsb * ((lo >> 8) & 0xff);
49}
50
51static int eps_set_state(struct eps_cpu_data *centaur,
52 unsigned int cpu,
53 u32 dest_state)
54{
55 struct cpufreq_freqs freqs;
56 u32 lo, hi;
57 int err = 0;
58 int i;
59
60 freqs.old = eps_get(cpu);
61 freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
62 freqs.cpu = cpu;
63 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
64
65 /* Wait while CPU is busy */
66 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
67 i = 0;
68 while (lo & ((1 << 16) | (1 << 17))) {
69 udelay(16);
70 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
71 i++;
72 if (unlikely(i > 64)) {
73 err = -ENODEV;
74 goto postchange;
75 }
76 }
77 /* Set new multiplier and voltage */
78 wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
79 /* Wait until transition end */
80 i = 0;
81 do {
82 udelay(16);
83 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
84 i++;
85 if (unlikely(i > 64)) {
86 err = -ENODEV;
87 goto postchange;
88 }
89 } while (lo & ((1 << 16) | (1 << 17)));
90
91 /* Return current frequency */
92postchange:
93 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
94 freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
95
96 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
97 return err;
98}
99
100static int eps_target(struct cpufreq_policy *policy,
101 unsigned int target_freq,
102 unsigned int relation)
103{
104 struct eps_cpu_data *centaur;
105 unsigned int newstate = 0;
106 unsigned int cpu = policy->cpu;
107 unsigned int dest_state;
108 int ret;
109
110 if (unlikely(eps_cpu[cpu] == NULL))
111 return -ENODEV;
112 centaur = eps_cpu[cpu];
113
114 if (unlikely(cpufreq_frequency_table_target(policy,
115 &eps_cpu[cpu]->freq_table[0],
116 target_freq,
117 relation,
118 &newstate))) {
119 return -EINVAL;
120 }
121
122 /* Make frequency transition */
123 dest_state = centaur->freq_table[newstate].index & 0xffff;
124 ret = eps_set_state(centaur, cpu, dest_state);
125 if (ret)
126 printk(KERN_ERR "eps: Timeout!\n");
127 return ret;
128}
129
130static int eps_verify(struct cpufreq_policy *policy)
131{
132 return cpufreq_frequency_table_verify(policy,
133 &eps_cpu[policy->cpu]->freq_table[0]);
134}
135
136static int eps_cpu_init(struct cpufreq_policy *policy)
137{
138 unsigned int i;
139 u32 lo, hi;
140 u64 val;
141 u8 current_multiplier, current_voltage;
142 u8 max_multiplier, max_voltage;
143 u8 min_multiplier, min_voltage;
144 u8 brand;
145 u32 fsb;
146 struct eps_cpu_data *centaur;
147 struct cpufreq_frequency_table *f_table;
148 int k, step, voltage;
149 int ret;
150 int states;
151
152 if (policy->cpu != 0)
153 return -ENODEV;
154
155 /* Check brand */
156 printk("eps: Detected VIA ");
157 rdmsr(0x1153, lo, hi);
158 brand = (((lo >> 2) ^ lo) >> 18) & 3;
159 switch(brand) {
160 case EPS_BRAND_C7M:
161 printk("C7-M\n");
162 break;
163 case EPS_BRAND_C7:
164 printk("C7\n");
165 break;
166 case EPS_BRAND_EDEN:
167 printk("Eden\n");
168 break;
169 case EPS_BRAND_C3:
170 printk("C3\n");
171 return -ENODEV;
172 break;
173 }
174 /* Enable Enhanced PowerSaver */
175 rdmsrl(MSR_IA32_MISC_ENABLE, val);
176 if (!(val & 1 << 16)) {
177 val |= 1 << 16;
178 wrmsrl(MSR_IA32_MISC_ENABLE, val);
179 /* Can be locked at 0 */
180 rdmsrl(MSR_IA32_MISC_ENABLE, val);
181 if (!(val & 1 << 16)) {
182 printk("eps: Can't enable Enhanced PowerSaver\n");
183 return -ENODEV;
184 }
185 }
186
187 /* Print voltage and multiplier */
188 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
189 current_voltage = lo & 0xff;
190 printk("eps: Current voltage = %dmV\n", current_voltage * 16 + 700);
191 current_multiplier = (lo >> 8) & 0xff;
192 printk("eps: Current multiplier = %d\n", current_multiplier);
193
194 /* Print limits */
195 max_voltage = hi & 0xff;
196 printk("eps: Highest voltage = %dmV\n", max_voltage * 16 + 700);
197 max_multiplier = (hi >> 8) & 0xff;
198 printk("eps: Highest multiplier = %d\n", max_multiplier);
199 min_voltage = (hi >> 16) & 0xff;
200 printk("eps: Lowest voltage = %dmV\n", min_voltage * 16 + 700);
201 min_multiplier = (hi >> 24) & 0xff;
202 printk("eps: Lowest multiplier = %d\n", min_multiplier);
203
204 /* Sanity checks */
205 if (current_multiplier == 0 || max_multiplier == 0
206 || min_multiplier == 0)
207 return -EINVAL;
208 if (current_multiplier > max_multiplier
209 || max_multiplier <= min_multiplier)
210 return -EINVAL;
211 if (current_voltage > 0x1c || max_voltage > 0x1c)
212 return -EINVAL;
213 if (max_voltage < min_voltage)
214 return -EINVAL;
215
216 /* Calc FSB speed */
217 fsb = cpu_khz / current_multiplier;
218 /* Calc number of p-states supported */
219 if (brand == EPS_BRAND_C7M)
220 states = max_multiplier - min_multiplier + 1;
221 else
222 states = 2;
223
224 /* Allocate private data and frequency table for current cpu */
225 centaur = kzalloc(sizeof(struct eps_cpu_data)
226 + (states + 1) * sizeof(struct cpufreq_frequency_table),
227 GFP_KERNEL);
228 if (!centaur)
229 return -ENOMEM;
230 eps_cpu[0] = centaur;
231
232 /* Copy basic values */
233 centaur->fsb = fsb;
234
235 /* Fill frequency and MSR value table */
236 f_table = &centaur->freq_table[0];
237 if (brand == EPS_BRAND_EDEN) {
238 f_table[0].frequency = fsb * min_multiplier;
239 f_table[0].index = (min_multiplier << 8) | min_voltage;
240 f_table[1].frequency = fsb * max_multiplier;
241 f_table[1].index = (max_multiplier << 8) | max_voltage;
242 f_table[2].frequency = CPUFREQ_TABLE_END;
243 } else {
244 k = 0;
245 step = ((max_voltage - min_voltage) * 256)
246 / (max_multiplier - min_multiplier);
247 for (i = min_multiplier; i <= max_multiplier; i++) {
248 voltage = (k * step) / 256 + min_voltage;
249 f_table[k].frequency = fsb * i;
250 f_table[k].index = (i << 8) | voltage;
251 k++;
252 }
253 f_table[k].frequency = CPUFREQ_TABLE_END;
254 }
255
256 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
257 policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
258 policy->cur = fsb * current_multiplier;
259
260 ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
261 if (ret) {
262 kfree(centaur);
263 return ret;
264 }
265
266 cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
267 return 0;
268}
269
270static int eps_cpu_exit(struct cpufreq_policy *policy)
271{
272 unsigned int cpu = policy->cpu;
273 struct eps_cpu_data *centaur;
274 u32 lo, hi;
275
276 if (eps_cpu[cpu] == NULL)
277 return -ENODEV;
278 centaur = eps_cpu[cpu];
279
280 /* Get max frequency */
281 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
282 /* Set max frequency */
283 eps_set_state(centaur, cpu, hi & 0xffff);
284 /* Bye */
285 cpufreq_frequency_table_put_attr(policy->cpu);
286 kfree(eps_cpu[cpu]);
287 eps_cpu[cpu] = NULL;
288 return 0;
289}
290
291static struct freq_attr* eps_attr[] = {
292 &cpufreq_freq_attr_scaling_available_freqs,
293 NULL,
294};
295
296static struct cpufreq_driver eps_driver = {
297 .verify = eps_verify,
298 .target = eps_target,
299 .init = eps_cpu_init,
300 .exit = eps_cpu_exit,
301 .get = eps_get,
302 .name = "e_powersaver",
303 .owner = THIS_MODULE,
304 .attr = eps_attr,
305};
306
307static int __init eps_init(void)
308{
309 struct cpuinfo_x86 *c = cpu_data;
310
311 /* This driver will work only on Centaur C7 processors with
312 * Enhanced SpeedStep/PowerSaver registers */
313 if (c->x86_vendor != X86_VENDOR_CENTAUR
314 || c->x86 != 6 || c->x86_model != 10)
315 return -ENODEV;
316 if (!cpu_has(c, X86_FEATURE_EST))
317 return -ENODEV;
318
319 if (cpufreq_register_driver(&eps_driver))
320 return -EINVAL;
321 return 0;
322}
323
324static void __exit eps_exit(void)
325{
326 cpufreq_unregister_driver(&eps_driver);
327}
328
329MODULE_AUTHOR("Rafa� Bilski <rafalbilski@interia.pl>");
330MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
331MODULE_LICENSE("GPL");
332
333module_init(eps_init);
334module_exit(eps_exit);