blob: 7bac808804f3ad61bce2643c5c00665777f98afd [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Dave Jones6ccf58a2006-06-05 15:25:20 -04002 * (C) 2004-2006 Sebastian Witt <se.witt@gmx.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Licensed under the terms of the GNU GPL License version 2.
5 * Based upon reverse engineered information
6 *
7 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
8 */
9
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
27
28/* Delay in ms between FSB changes */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +020029/* #define NFORCE2_DELAY 10 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +020031/*
32 * nforce2_chipset:
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 * FSB is changed using the chipset
34 */
Dave Jonesb5c91662009-01-17 22:39:47 -050035static struct pci_dev *nforce2_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
37/* fid:
38 * multiplier * 10
39 */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +020040static int fid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42/* min_fsb, max_fsb:
Dave Jones32ee8c32006-02-28 00:43:23 -050043 * minimum and maximum FSB (= FSB at boot time)
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +020045static int min_fsb;
46static int max_fsb;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
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,
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +020057 "Minimum FSB to use, if not defined: current FSB - 50");
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Dave Jones20174b62009-01-17 22:42:19 -050059#define PFX "cpufreq-nforce2: "
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Dave Jones32ee8c32006-02-28 00:43:23 -050061/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 * nforce2_calc_fsb - calculate FSB
63 * @pll: PLL value
Dave Jones32ee8c32006-02-28 00:43:23 -050064 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 * Calculates FSB from PLL value
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
Dave Jones32ee8c32006-02-28 00:43:23 -050080/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 * nforce2_calc_pll - calculate PLL value
82 * @fsb: FSB
Dave Jones32ee8c32006-02-28 00:43:23 -050083 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 * Calculate PLL value for given FSB
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 /* Try to calculate multiplier and divider up to 4 times */
93 while (((mul == 0) || (div == 0)) && (tried <= 3)) {
Dave Jones6ccf58a2006-06-05 15:25:20 -040094 for (xdiv = 2; xdiv <= 0x80; xdiv++)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 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
Dave Jones32ee8c32006-02-28 00:43:23 -0500110/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 * nforce2_write_pll - write PLL value to chipset
112 * @pll: PLL value
Dave Jones32ee8c32006-02-28 00:43:23 -0500113 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 * Writes new FSB PLL value to chipset
115 */
116static void nforce2_write_pll(int pll)
117{
118 int temp;
119
120 /* Set the pll addr. to 0x00 */
Dave Jonesb5c91662009-01-17 22:39:47 -0500121 pci_write_config_dword(nforce2_dev, NFORCE2_PLLADR, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123 /* Now write the value in all 64 registers */
Dave Jones32ee8c32006-02-28 00:43:23 -0500124 for (temp = 0; temp <= 0x3f; temp++)
Dave Jonesb5c91662009-01-17 22:39:47 -0500125 pci_write_config_dword(nforce2_dev, NFORCE2_PLLREG, pll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127 return;
128}
129
Dave Jones32ee8c32006-02-28 00:43:23 -0500130/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 * nforce2_fsb_read - Read FSB
132 *
133 * Read FSB from chipset
134 * If bootfsb != 0, return FSB at boot-time
135 */
136static unsigned int nforce2_fsb_read(int bootfsb)
137{
138 struct pci_dev *nforce2_sub5;
139 u32 fsb, temp = 0;
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 /* Get chipset boot FSB from subdevice 5 (FSB at boot-time) */
Dave Jonesb5c91662009-01-17 22:39:47 -0500142 nforce2_sub5 = pci_get_subsys(PCI_VENDOR_ID_NVIDIA, 0x01EF,
143 PCI_ANY_ID, PCI_ANY_ID, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 if (!nforce2_sub5)
145 return 0;
146
147 pci_read_config_dword(nforce2_sub5, NFORCE2_BOOTFSB, &fsb);
148 fsb /= 1000000;
Dave Jones32ee8c32006-02-28 00:43:23 -0500149
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 /* Check if PLL register is already set */
Dave Jonesb5c91662009-01-17 22:39:47 -0500151 pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp);
Dave Jones32ee8c32006-02-28 00:43:23 -0500152
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200153 if (bootfsb || !temp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 return fsb;
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 /* Use PLL register FSB value */
Dave Jonesb5c91662009-01-17 22:39:47 -0500157 pci_read_config_dword(nforce2_dev, NFORCE2_PLLREG, &temp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 fsb = nforce2_calc_fsb(temp);
159
160 return fsb;
161}
162
Dave Jones32ee8c32006-02-28 00:43:23 -0500163/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 * nforce2_set_fsb - set new FSB
165 * @fsb: New FSB
Dave Jones32ee8c32006-02-28 00:43:23 -0500166 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 * Sets new FSB
168 */
169static int nforce2_set_fsb(unsigned int fsb)
170{
Gabriel A. Devenyid4921912005-12-01 01:09:22 -0800171 u32 temp = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 unsigned int tfsb;
173 int diff;
Gabriel A. Devenyid4921912005-12-01 01:09:22 -0800174 int pll = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 if ((fsb > max_fsb) || (fsb < NFORCE2_MIN_FSB)) {
Dave Jones20174b62009-01-17 22:42:19 -0500177 printk(KERN_ERR PFX "FSB %d is out of range!\n", fsb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 return -EINVAL;
179 }
Dave Jones32ee8c32006-02-28 00:43:23 -0500180
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 tfsb = nforce2_fsb_read(0);
182 if (!tfsb) {
Dave Jones20174b62009-01-17 22:42:19 -0500183 printk(KERN_ERR PFX "Error while reading the FSB\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 return -EINVAL;
185 }
186
187 /* First write? Then set actual value */
Dave Jonesb5c91662009-01-17 22:39:47 -0500188 pci_read_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8 *)&temp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 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 /* Enable write access */
199 temp = 0x01;
Dave Jonesb5c91662009-01-17 22:39:47 -0500200 pci_write_config_byte(nforce2_dev, NFORCE2_PLLENABLE, (u8)temp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
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 /* Calculate the PLL reg. value */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200214 pll = nforce2_calc_pll(tfsb);
215 if (pll == -1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 return -EINVAL;
Dave Jones32ee8c32006-02-28 00:43:23 -0500217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 nforce2_write_pll(pll);
219#ifdef NFORCE2_DELAY
220 mdelay(NFORCE2_DELAY);
221#endif
222 }
223
224 temp = 0x40;
Dave Jonesb5c91662009-01-17 22:39:47 -0500225 pci_write_config_byte(nforce2_dev, NFORCE2_PLLADR, (u8)temp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 return 0;
228}
229
230/**
231 * nforce2_get - get the CPU frequency
232 * @cpu: CPU number
Dave Jones32ee8c32006-02-28 00:43:23 -0500233 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 * Returns the CPU frequency
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
243/**
244 * nforce2_target - set a new CPUFreq policy
245 * @policy: new policy
246 * @target_freq: the target frequency
Dave Jonesb5c91662009-01-17 22:39:47 -0500247 * @relation: how that frequency relates to achieved frequency
248 * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 *
250 * Sets a new CPUFreq policy.
251 */
252static int nforce2_target(struct cpufreq_policy *policy,
253 unsigned int target_freq, unsigned int relation)
254{
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200255/* unsigned long flags; */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 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;
Simon Arlott27b46d72007-10-20 01:13:56 +0200266 freqs.cpu = 0; /* Only one CPU on nForce2 platforms */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
268 if (freqs.old == freqs.new)
269 return 0;
270
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200271 pr_debug("Old CPU frequency %d kHz, new %d kHz\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 freqs.old, freqs.new);
273
274 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
275
276 /* Disable IRQs */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200277 /* local_irq_save(flags); */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
279 if (nforce2_set_fsb(target_fsb) < 0)
Dave Jones20174b62009-01-17 22:42:19 -0500280 printk(KERN_ERR PFX "Changing FSB to %d failed\n",
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200281 target_fsb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 else
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200283 pr_debug("Changed FSB successfully to %d\n",
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200284 target_fsb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285
286 /* Enable IRQs */
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200287 /* local_irq_restore(flags); */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
289 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
290
291 return 0;
292}
293
294/**
295 * nforce2_verify - verifies a new CPUFreq policy
296 * @policy: new policy
297 */
298static int nforce2_verify(struct cpufreq_policy *policy)
299{
300 unsigned int fsb_pol_max;
301
302 fsb_pol_max = policy->max / (fid * 100);
303
304 if (policy->min < (fsb_pol_max * fid * 100))
305 policy->max = (fsb_pol_max + 1) * fid * 100;
306
307 cpufreq_verify_within_limits(policy,
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200308 policy->cpuinfo.min_freq,
309 policy->cpuinfo.max_freq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 return 0;
311}
312
313static int nforce2_cpu_init(struct cpufreq_policy *policy)
314{
315 unsigned int fsb;
316 unsigned int rfid;
317
318 /* capability check */
319 if (policy->cpu != 0)
320 return -ENODEV;
321
322 /* Get current FSB */
323 fsb = nforce2_fsb_read(0);
324
325 if (!fsb)
326 return -EIO;
327
328 /* FIX: Get FID from CPU */
329 if (!fid) {
330 if (!cpu_khz) {
Dave Jones20174b62009-01-17 22:42:19 -0500331 printk(KERN_WARNING PFX
332 "cpu_khz not set, can't calculate multiplier!\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 return -ENODEV;
334 }
335
336 fid = cpu_khz / (fsb * 100);
337 rfid = fid % 5;
338
339 if (rfid) {
340 if (rfid > 2)
341 fid += 5 - rfid;
342 else
343 fid -= rfid;
344 }
345 }
346
Dave Jones20174b62009-01-17 22:42:19 -0500347 printk(KERN_INFO PFX "FSB currently at %i MHz, FID %d.%d\n", fsb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 fid / 10, fid % 10);
Dave Jones32ee8c32006-02-28 00:43:23 -0500349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 /* Set maximum FSB to FSB at boot time */
351 max_fsb = nforce2_fsb_read(1);
Dave Jones32ee8c32006-02-28 00:43:23 -0500352
Paolo Ciarrocchi219835f2008-06-14 21:11:39 +0200353 if (!max_fsb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 return -EIO;
355
356 if (!min_fsb)
357 min_fsb = max_fsb - NFORCE2_SAFE_DISTANCE;
358
359 if (min_fsb < NFORCE2_MIN_FSB)
360 min_fsb = NFORCE2_MIN_FSB;
361
362 /* cpuinfo and default policy values */
363 policy->cpuinfo.min_freq = min_fsb * fid * 100;
364 policy->cpuinfo.max_freq = max_fsb * fid * 100;
365 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
366 policy->cur = nforce2_get(policy->cpu);
367 policy->min = policy->cpuinfo.min_freq;
368 policy->max = policy->cpuinfo.max_freq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
370 return 0;
371}
372
373static int nforce2_cpu_exit(struct cpufreq_policy *policy)
374{
375 return 0;
376}
377
Linus Torvalds221dee22007-02-26 14:55:48 -0800378static struct cpufreq_driver nforce2_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 .name = "nforce2",
380 .verify = nforce2_verify,
381 .target = nforce2_target,
382 .get = nforce2_get,
383 .init = nforce2_cpu_init,
384 .exit = nforce2_cpu_exit,
385 .owner = THIS_MODULE,
386};
387
388/**
389 * nforce2_detect_chipset - detect the Southbridge which contains FSB PLL logic
390 *
391 * Detects nForce2 A2 and C1 stepping
Dave Jones32ee8c32006-02-28 00:43:23 -0500392 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 */
Julia Lawallb2a33c12010-09-05 21:00:20 +0200394static int nforce2_detect_chipset(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395{
Dave Jonesb5c91662009-01-17 22:39:47 -0500396 nforce2_dev = pci_get_subsys(PCI_VENDOR_ID_NVIDIA,
Dave Jones32ee8c32006-02-28 00:43:23 -0500397 PCI_DEVICE_ID_NVIDIA_NFORCE2,
398 PCI_ANY_ID, PCI_ANY_ID, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
Dave Jonesb5c91662009-01-17 22:39:47 -0500400 if (nforce2_dev == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 return -ENODEV;
402
Dave Jones20174b62009-01-17 22:42:19 -0500403 printk(KERN_INFO PFX "Detected nForce2 chipset revision %X\n",
Dave Jonesb5c91662009-01-17 22:39:47 -0500404 nforce2_dev->revision);
Dave Jones20174b62009-01-17 22:42:19 -0500405 printk(KERN_INFO PFX
406 "FSB changing is maybe unstable and can lead to "
Dave Jonesb5c91662009-01-17 22:39:47 -0500407 "crashes and data loss.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
409 return 0;
410}
411
412/**
413 * nforce2_init - initializes the nForce2 CPUFreq driver
414 *
415 * Initializes the nForce2 FSB support. Returns -ENODEV on unsupported
416 * devices, -EINVAL on problems during initiatization, and zero on
417 * success.
418 */
419static int __init nforce2_init(void)
420{
421 /* TODO: do we need to detect the processor? */
422
423 /* detect chipset */
424 if (nforce2_detect_chipset()) {
Matthew Garretteb3092c2009-02-21 01:58:47 +0000425 printk(KERN_INFO PFX "No nForce2 chipset.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 return -ENODEV;
427 }
428
429 return cpufreq_register_driver(&nforce2_driver);
430}
431
432/**
433 * nforce2_exit - unregisters cpufreq module
434 *
435 * Unregisters nForce2 FSB change support.
436 */
437static void __exit nforce2_exit(void)
438{
439 cpufreq_unregister_driver(&nforce2_driver);
440}
441
442module_init(nforce2_init);
443module_exit(nforce2_exit);
444