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10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/moduleparam.h>
13#include <linux/init.h>
14#include <linux/cpufreq.h>
15#include <linux/pci.h>
16#include <linux/delay.h>
17
18#define NFORCE2_XTAL 25
19#define NFORCE2_BOOTFSB 0x48
20#define NFORCE2_PLLENABLE 0xa8
21#define NFORCE2_PLLREG 0xa4
22#define NFORCE2_PLLADR 0xa0
23#define NFORCE2_PLL(mul, div) (0x100000 | (mul << 8) | div)
24
25#define NFORCE2_MIN_FSB 50
26#define NFORCE2_SAFE_DISTANCE 50
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32
33
34
35static struct pci_dev *nforce2_dev;
36
37
38
39
40static int fid;
41
42
43
44
45static int min_fsb;
46static int max_fsb;
47
48MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>");
49MODULE_DESCRIPTION("nForce2 FSB changing cpufreq driver");
50MODULE_LICENSE("GPL");
51
52module_param(fid, int, 0444);
53module_param(min_fsb, int, 0444);
54
55MODULE_PARM_DESC(fid, "CPU multiplier to use (11.5 = 115)");
56MODULE_PARM_DESC(min_fsb,
57 "Minimum FSB to use, if not defined: current FSB - 50");
58
59#define PFX "cpufreq-nforce2: "
60
61
62
63
64
65
66
67static int nforce2_calc_fsb(int pll)
68{
69 unsigned char mul, div;
70
71 mul = (pll >> 8) & 0xff;
72 div = pll & 0xff;
73
74 if (div > 0)
75 return NFORCE2_XTAL * mul / div;
76
77 return 0;
78}
79
80
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83
84
85
86static int nforce2_calc_pll(unsigned int fsb)
87{
88 unsigned char xmul, xdiv;
89 unsigned char mul = 0, div = 0;
90 int tried = 0;
91
92
93 while (((mul == 0) || (div == 0)) && (tried <= 3)) {
94 for (xdiv = 2; xdiv <= 0x80; xdiv++)
95 for (xmul = 1; xmul <= 0xfe; xmul++)
96 if (nforce2_calc_fsb(NFORCE2_PLL(xmul, xdiv)) ==
97 fsb + tried) {
98 mul = xmul;
99 div = xdiv;
100 }
101 tried++;
102 }
103
104 if ((mul == 0) || (div == 0))
105 return -1;
106
107 return NFORCE2_PLL(mul, div);
108}
109
110
111
112
113
114
115
116static void nforce2_write_pll(int pll)
117{
118 int temp;
119
120
121 pci_write_config_dword(nforce2_dev, NFORCE2_PLLADR, 0);
122
123
124 for (temp = 0; temp <= 0x3f; temp++)
125 pci_write_config_dword(nforce2_dev, NFORCE2_PLLREG, pll);
126
127 return;
128}
129
130
131
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133
134
135
136static unsigned int nforce2_fsb_read(int bootfsb)
137{
138 struct pci_dev *nforce2_sub5;
139 u32 fsb, temp = 0;
140
141
142 nforce2_sub5 = pci_get_subsys(PCI_VENDOR_ID_NVIDIA, 0x01EF,
143 PCI_ANY_ID, PCI_ANY_ID, NULL);
144 if (!nforce2_sub5)
145 return 0;
146
147 pci_read_config_dword(nforce2_sub5, NFORCE2_BOOTFSB, &fsb);
148 fsb /= 1000000;
149
150
151 pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp);
152
153 if (bootfsb || !temp)
154 return fsb;
155
156
157 pci_read_config_dword(nforce2_dev, NFORCE2_PLLREG, &temp);
158 fsb = nforce2_calc_fsb(temp);
159
160 return fsb;
161}
162
163
164
165
166
167
168
169static int nforce2_set_fsb(unsigned int fsb)
170{
171 u32 temp = 0;
172 unsigned int tfsb;
173 int diff;
174 int pll = 0;
175
176 if ((fsb > max_fsb) || (fsb < NFORCE2_MIN_FSB)) {
177 printk(KERN_ERR PFX "FSB %d is out of range!\n", fsb);
178 return -EINVAL;
179 }
180
181 tfsb = nforce2_fsb_read(0);
182 if (!tfsb) {
183 printk(KERN_ERR PFX "Error while reading the FSB\n");
184 return -EINVAL;
185 }
186
187
188 pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp);
189 if (!temp) {
190 pll = nforce2_calc_pll(tfsb);
191
192 if (pll < 0)
193 return -EINVAL;
194
195 nforce2_write_pll(pll);
196 }
197
198
199 temp = 0x01;
200 pci_write_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8)temp);
201
202 diff = tfsb - fsb;
203
204 if (!diff)
205 return 0;
206
207 while ((tfsb != fsb) && (tfsb <= max_fsb) && (tfsb >= min_fsb)) {
208 if (diff < 0)
209 tfsb++;
210 else
211 tfsb--;
212
213
214 pll = nforce2_calc_pll(tfsb);
215 if (pll == -1)
216 return -EINVAL;
217
218 nforce2_write_pll(pll);
219#ifdef NFORCE2_DELAY
220 mdelay(NFORCE2_DELAY);
221#endif
222 }
223
224 temp = 0x40;
225 pci_write_config_byte(nforce2_dev, NFORCE2_PLLADR, (u8)temp);
226
227 return 0;
228}
229
230
231
232
233
234
235
236static unsigned int nforce2_get(unsigned int cpu)
237{
238 if (cpu)
239 return 0;
240 return nforce2_fsb_read(0) * fid * 100;
241}
242
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250
251
252static int nforce2_target(struct cpufreq_policy *policy,
253 unsigned int target_freq, unsigned int relation)
254{
255
256 struct cpufreq_freqs freqs;
257 unsigned int target_fsb;
258
259 if ((target_freq > policy->max) || (target_freq < policy->min))
260 return -EINVAL;
261
262 target_fsb = target_freq / (fid * 100);
263
264 freqs.old = nforce2_get(policy->cpu);
265 freqs.new = target_fsb * fid * 100;
266
267 if (freqs.old == freqs.new)
268 return 0;
269
270 pr_debug("Old CPU frequency %d kHz, new %d kHz\n",
271 freqs.old, freqs.new);
272
273 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
274
275
276
277
278 if (nforce2_set_fsb(target_fsb) < 0)
279 printk(KERN_ERR PFX "Changing FSB to %d failed\n",
280 target_fsb);
281 else
282 pr_debug("Changed FSB successfully to %d\n",
283 target_fsb);
284
285
286
287
288 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
289
290 return 0;
291}
292
293
294
295
296
297static int nforce2_verify(struct cpufreq_policy *policy)
298{
299 unsigned int fsb_pol_max;
300
301 fsb_pol_max = policy->max / (fid * 100);
302
303 if (policy->min < (fsb_pol_max * fid * 100))
304 policy->max = (fsb_pol_max + 1) * fid * 100;
305
306 cpufreq_verify_within_limits(policy,
307 policy->cpuinfo.min_freq,
308 policy->cpuinfo.max_freq);
309 return 0;
310}
311
312static int nforce2_cpu_init(struct cpufreq_policy *policy)
313{
314 unsigned int fsb;
315 unsigned int rfid;
316
317
318 if (policy->cpu != 0)
319 return -ENODEV;
320
321
322 fsb = nforce2_fsb_read(0);
323
324 if (!fsb)
325 return -EIO;
326
327
328 if (!fid) {
329 if (!cpu_khz) {
330 printk(KERN_WARNING PFX
331 "cpu_khz not set, can't calculate multiplier!\n");
332 return -ENODEV;
333 }
334
335 fid = cpu_khz / (fsb * 100);
336 rfid = fid % 5;
337
338 if (rfid) {
339 if (rfid > 2)
340 fid += 5 - rfid;
341 else
342 fid -= rfid;
343 }
344 }
345
346 printk(KERN_INFO PFX "FSB currently at %i MHz, FID %d.%d\n", fsb,
347 fid / 10, fid % 10);
348
349
350 max_fsb = nforce2_fsb_read(1);
351
352 if (!max_fsb)
353 return -EIO;
354
355 if (!min_fsb)
356 min_fsb = max_fsb - NFORCE2_SAFE_DISTANCE;
357
358 if (min_fsb < NFORCE2_MIN_FSB)
359 min_fsb = NFORCE2_MIN_FSB;
360
361
362 policy->min = policy->cpuinfo.min_freq = min_fsb * fid * 100;
363 policy->max = policy->cpuinfo.max_freq = max_fsb * fid * 100;
364 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
365 policy->cur = nforce2_get(policy->cpu);
366
367 return 0;
368}
369
370static int nforce2_cpu_exit(struct cpufreq_policy *policy)
371{
372 return 0;
373}
374
375static struct cpufreq_driver nforce2_driver = {
376 .name = "nforce2",
377 .verify = nforce2_verify,
378 .target = nforce2_target,
379 .get = nforce2_get,
380 .init = nforce2_cpu_init,
381 .exit = nforce2_cpu_exit,
382};
383
384#ifdef MODULE
385static DEFINE_PCI_DEVICE_TABLE(nforce2_ids) = {
386 { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE2 },
387 {}
388};
389MODULE_DEVICE_TABLE(pci, nforce2_ids);
390#endif
391
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393
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395
396
397
398static int nforce2_detect_chipset(void)
399{
400 nforce2_dev = pci_get_subsys(PCI_VENDOR_ID_NVIDIA,
401 PCI_DEVICE_ID_NVIDIA_NFORCE2,
402 PCI_ANY_ID, PCI_ANY_ID, NULL);
403
404 if (nforce2_dev == NULL)
405 return -ENODEV;
406
407 printk(KERN_INFO PFX "Detected nForce2 chipset revision %X\n",
408 nforce2_dev->revision);
409 printk(KERN_INFO PFX
410 "FSB changing is maybe unstable and can lead to "
411 "crashes and data loss.\n");
412
413 return 0;
414}
415
416
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418
419
420
421
422
423static int __init nforce2_init(void)
424{
425
426
427
428 if (nforce2_detect_chipset()) {
429 printk(KERN_INFO PFX "No nForce2 chipset.\n");
430 return -ENODEV;
431 }
432
433 return cpufreq_register_driver(&nforce2_driver);
434}
435
436
437
438
439
440
441static void __exit nforce2_exit(void)
442{
443 cpufreq_unregister_driver(&nforce2_driver);
444}
445
446module_init(nforce2_init);
447module_exit(nforce2_exit);
448
449