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1/*
2 * Cyrix MediaGX and NatSemi Geode Suspend Modulation
3 * (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
4 * (C) 2002 Hiroshi Miura <miura@da-cha.org>
5 * All Rights Reserved
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation
10 *
11 * The author(s) of this software shall not be held liable for damages
12 * of any nature resulting due to the use of this software. This
13 * software is provided AS-IS with no warranties.
14 *
15 * Theoretical note:
16 *
17 * (see Geode(tm) CS5530 manual (rev.4.1) page.56)
18 *
19 * CPU frequency control on NatSemi Geode GX1/GXLV processor and CS55x0
20 * are based on Suspend Modulation.
21 *
22 * Suspend Modulation works by asserting and de-asserting the SUSP# pin
23 * to CPU(GX1/GXLV) for configurable durations. When asserting SUSP#
24 * the CPU enters an idle state. GX1 stops its core clock when SUSP# is
25 * asserted then power consumption is reduced.
26 *
27 * Suspend Modulation's OFF/ON duration are configurable
28 * with 'Suspend Modulation OFF Count Register'
29 * and 'Suspend Modulation ON Count Register'.
30 * These registers are 8bit counters that represent the number of
31 * 32us intervals which the SUSP# pin is asserted(ON)/de-asserted(OFF)
32 * to the processor.
33 *
34 * These counters define a ratio which is the effective frequency
35 * of operation of the system.
36 *
37 * OFF Count
38 * F_eff = Fgx * ----------------------
39 * OFF Count + ON Count
40 *
41 * 0 <= On Count, Off Count <= 255
42 *
43 * From these limits, we can get register values
44 *
45 * off_duration + on_duration <= MAX_DURATION
46 * on_duration = off_duration * (stock_freq - freq) / freq
47 *
48 * off_duration = (freq * DURATION) / stock_freq
49 * on_duration = DURATION - off_duration
50 *
51 *
52 *---------------------------------------------------------------------------
53 *
54 * ChangeLog:
55 * Dec. 12, 2003 Hiroshi Miura <miura@da-cha.org>
56 * - fix on/off register mistake
57 * - fix cpu_khz calc when it stops cpu modulation.
58 *
59 * Dec. 11, 2002 Hiroshi Miura <miura@da-cha.org>
60 * - rewrite for Cyrix MediaGX Cx5510/5520 and
61 * NatSemi Geode Cs5530(A).
62 *
63 * Jul. ??, 2002 Zwane Mwaikambo <zwane@commfireservices.com>
64 * - cs5530_mod patch for 2.4.19-rc1.
65 *
66 *---------------------------------------------------------------------------
67 *
68 * Todo
69 * Test on machines with 5510, 5530, 5530A
70 */
71
72/************************************************************************
73 * Suspend Modulation - Definitions *
74 ************************************************************************/
75
76#include <linux/kernel.h>
77#include <linux/module.h>
78#include <linux/init.h>
79#include <linux/smp.h>
80#include <linux/cpufreq.h>
81#include <linux/pci.h>
82#include <linux/errno.h>
83#include <linux/slab.h>
84
85#include <asm/processor-cyrix.h>
86
87/* PCI config registers, all at F0 */
88#define PCI_PMER1 0x80 /* power management enable register 1 */
89#define PCI_PMER2 0x81 /* power management enable register 2 */
90#define PCI_PMER3 0x82 /* power management enable register 3 */
91#define PCI_IRQTC 0x8c /* irq speedup timer counter register:typical 2 to 4ms */
92#define PCI_VIDTC 0x8d /* video speedup timer counter register: typical 50 to 100ms */
93#define PCI_MODOFF 0x94 /* suspend modulation OFF counter register, 1 = 32us */
94#define PCI_MODON 0x95 /* suspend modulation ON counter register */
95#define PCI_SUSCFG 0x96 /* suspend configuration register */
96
97/* PMER1 bits */
98#define GPM (1<<0) /* global power management */
99#define GIT (1<<1) /* globally enable PM device idle timers */
100#define GTR (1<<2) /* globally enable IO traps */
101#define IRQ_SPDUP (1<<3) /* disable clock throttle during interrupt handling */
102#define VID_SPDUP (1<<4) /* disable clock throttle during vga video handling */
103
104/* SUSCFG bits */
105#define SUSMOD (1<<0) /* enable/disable suspend modulation */
106/* the below is supported only with cs5530 (after rev.1.2)/cs5530A */
107#define SMISPDUP (1<<1) /* select how SMI re-enable suspend modulation: */
108 /* IRQTC timer or read SMI speedup disable reg.(F1BAR[08-09h]) */
109#define SUSCFG (1<<2) /* enable powering down a GXLV processor. "Special 3Volt Suspend" mode */
110/* the below is supported only with cs5530A */
111#define PWRSVE_ISA (1<<3) /* stop ISA clock */
112#define PWRSVE (1<<4) /* active idle */
113
114struct gxfreq_params {
115 u8 on_duration;
116 u8 off_duration;
117 u8 pci_suscfg;
118 u8 pci_pmer1;
119 u8 pci_pmer2;
120 struct pci_dev *cs55x0;
121};
122
123static struct gxfreq_params *gx_params;
124static int stock_freq;
125
126/* PCI bus clock - defaults to 30.000 if cpu_khz is not available */
127static int pci_busclk;
128module_param(pci_busclk, int, 0444);
129
130/* maximum duration for which the cpu may be suspended
131 * (32us * MAX_DURATION). If no parameter is given, this defaults
132 * to 255.
133 * Note that this leads to a maximum of 8 ms(!) where the CPU clock
134 * is suspended -- processing power is just 0.39% of what it used to be,
135 * though. 781.25 kHz(!) for a 200 MHz processor -- wow. */
136static int max_duration = 255;
137module_param(max_duration, int, 0444);
138
139/* For the default policy, we want at least some processing power
140 * - let's say 5%. (min = maxfreq / POLICY_MIN_DIV)
141 */
142#define POLICY_MIN_DIV 20
143
144
145/**
146 * we can detect a core multipiler from dir0_lsb
147 * from GX1 datasheet p.56,
148 * MULT[3:0]:
149 * 0000 = SYSCLK multiplied by 4 (test only)
150 * 0001 = SYSCLK multiplied by 10
151 * 0010 = SYSCLK multiplied by 4
152 * 0011 = SYSCLK multiplied by 6
153 * 0100 = SYSCLK multiplied by 9
154 * 0101 = SYSCLK multiplied by 5
155 * 0110 = SYSCLK multiplied by 7
156 * 0111 = SYSCLK multiplied by 8
157 * of 33.3MHz
158 **/
159static int gx_freq_mult[16] = {
160 4, 10, 4, 6, 9, 5, 7, 8,
161 0, 0, 0, 0, 0, 0, 0, 0
162};
163
164
165/****************************************************************
166 * Low Level chipset interface *
167 ****************************************************************/
168static struct pci_device_id gx_chipset_tbl[] __initdata = {
169 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY), },
170 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5520), },
171 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5510), },
172 { 0, },
173};
174
175static void gx_write_byte(int reg, int value)
176{
177 pci_write_config_byte(gx_params->cs55x0, reg, value);
178}
179
180/**
181 * gx_detect_chipset:
182 *
183 **/
184static __init struct pci_dev *gx_detect_chipset(void)
185{
186 struct pci_dev *gx_pci = NULL;
187
188 /* check if CPU is a MediaGX or a Geode. */
189 if ((boot_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
190 (boot_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
191 pr_debug("error: no MediaGX/Geode processor found!\n");
192 return NULL;
193 }
194
195 /* detect which companion chip is used */
196 for_each_pci_dev(gx_pci) {
197 if ((pci_match_id(gx_chipset_tbl, gx_pci)) != NULL)
198 return gx_pci;
199 }
200
201 pr_debug("error: no supported chipset found!\n");
202 return NULL;
203}
204
205/**
206 * gx_get_cpuspeed:
207 *
208 * Finds out at which efficient frequency the Cyrix MediaGX/NatSemi
209 * Geode CPU runs.
210 */
211static unsigned int gx_get_cpuspeed(unsigned int cpu)
212{
213 if ((gx_params->pci_suscfg & SUSMOD) == 0)
214 return stock_freq;
215
216 return (stock_freq * gx_params->off_duration)
217 / (gx_params->on_duration + gx_params->off_duration);
218}
219
220/**
221 * gx_validate_speed:
222 * determine current cpu speed
223 *
224 **/
225
226static unsigned int gx_validate_speed(unsigned int khz, u8 *on_duration,
227 u8 *off_duration)
228{
229 unsigned int i;
230 u8 tmp_on, tmp_off;
231 int old_tmp_freq = stock_freq;
232 int tmp_freq;
233
234 *off_duration = 1;
235 *on_duration = 0;
236
237 for (i = max_duration; i > 0; i--) {
238 tmp_off = ((khz * i) / stock_freq) & 0xff;
239 tmp_on = i - tmp_off;
240 tmp_freq = (stock_freq * tmp_off) / i;
241 /* if this relation is closer to khz, use this. If it's equal,
242 * prefer it, too - lower latency */
243 if (abs(tmp_freq - khz) <= abs(old_tmp_freq - khz)) {
244 *on_duration = tmp_on;
245 *off_duration = tmp_off;
246 old_tmp_freq = tmp_freq;
247 }
248 }
249
250 return old_tmp_freq;
251}
252
253
254/**
255 * gx_set_cpuspeed:
256 * set cpu speed in khz.
257 **/
258
259static void gx_set_cpuspeed(unsigned int khz)
260{
261 u8 suscfg, pmer1;
262 unsigned int new_khz;
263 unsigned long flags;
264 struct cpufreq_freqs freqs;
265
266 freqs.cpu = 0;
267 freqs.old = gx_get_cpuspeed(0);
268
269 new_khz = gx_validate_speed(khz, &gx_params->on_duration,
270 &gx_params->off_duration);
271
272 freqs.new = new_khz;
273
274 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
275 local_irq_save(flags);
276
277
278
279 if (new_khz != stock_freq) {
280 /* if new khz == 100% of CPU speed, it is special case */
281 switch (gx_params->cs55x0->device) {
282 case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
283 pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
284 /* FIXME: need to test other values -- Zwane,Miura */
285 /* typical 2 to 4ms */
286 gx_write_byte(PCI_IRQTC, 4);
287 /* typical 50 to 100ms */
288 gx_write_byte(PCI_VIDTC, 100);
289 gx_write_byte(PCI_PMER1, pmer1);
290
291 if (gx_params->cs55x0->revision < 0x10) {
292 /* CS5530(rev 1.2, 1.3) */
293 suscfg = gx_params->pci_suscfg|SUSMOD;
294 } else {
295 /* CS5530A,B.. */
296 suscfg = gx_params->pci_suscfg|SUSMOD|PWRSVE;
297 }
298 break;
299 case PCI_DEVICE_ID_CYRIX_5520:
300 case PCI_DEVICE_ID_CYRIX_5510:
301 suscfg = gx_params->pci_suscfg | SUSMOD;
302 break;
303 default:
304 local_irq_restore(flags);
305 pr_debug("fatal: try to set unknown chipset.\n");
306 return;
307 }
308 } else {
309 suscfg = gx_params->pci_suscfg & ~(SUSMOD);
310 gx_params->off_duration = 0;
311 gx_params->on_duration = 0;
312 pr_debug("suspend modulation disabled: cpu runs 100%% speed.\n");
313 }
314
315 gx_write_byte(PCI_MODOFF, gx_params->off_duration);
316 gx_write_byte(PCI_MODON, gx_params->on_duration);
317
318 gx_write_byte(PCI_SUSCFG, suscfg);
319 pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);
320
321 local_irq_restore(flags);
322
323 gx_params->pci_suscfg = suscfg;
324
325 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
326
327 pr_debug("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
328 gx_params->on_duration * 32, gx_params->off_duration * 32);
329 pr_debug("suspend modulation w/ clock speed: %d kHz.\n", freqs.new);
330}
331
332/****************************************************************
333 * High level functions *
334 ****************************************************************/
335
336/*
337 * cpufreq_gx_verify: test if frequency range is valid
338 *
339 * This function checks if a given frequency range in kHz is valid
340 * for the hardware supported by the driver.
341 */
342
343static int cpufreq_gx_verify(struct cpufreq_policy *policy)
344{
345 unsigned int tmp_freq = 0;
346 u8 tmp1, tmp2;
347
348 if (!stock_freq || !policy)
349 return -EINVAL;
350
351 policy->cpu = 0;
352 cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
353 stock_freq);
354
355 /* it needs to be assured that at least one supported frequency is
356 * within policy->min and policy->max. If it is not, policy->max
357 * needs to be increased until one freuqency is supported.
358 * policy->min may not be decreased, though. This way we guarantee a
359 * specific processing capacity.
360 */
361 tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
362 if (tmp_freq < policy->min)
363 tmp_freq += stock_freq / max_duration;
364 policy->min = tmp_freq;
365 if (policy->min > policy->max)
366 policy->max = tmp_freq;
367 tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
368 if (tmp_freq > policy->max)
369 tmp_freq -= stock_freq / max_duration;
370 policy->max = tmp_freq;
371 if (policy->max < policy->min)
372 policy->max = policy->min;
373 cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
374 stock_freq);
375
376 return 0;
377}
378
379/*
380 * cpufreq_gx_target:
381 *
382 */
383static int cpufreq_gx_target(struct cpufreq_policy *policy,
384 unsigned int target_freq,
385 unsigned int relation)
386{
387 u8 tmp1, tmp2;
388 unsigned int tmp_freq;
389
390 if (!stock_freq || !policy)
391 return -EINVAL;
392
393 policy->cpu = 0;
394
395 tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
396 while (tmp_freq < policy->min) {
397 tmp_freq += stock_freq / max_duration;
398 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
399 }
400 while (tmp_freq > policy->max) {
401 tmp_freq -= stock_freq / max_duration;
402 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
403 }
404
405 gx_set_cpuspeed(tmp_freq);
406
407 return 0;
408}
409
410static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
411{
412 unsigned int maxfreq, curfreq;
413
414 if (!policy || policy->cpu != 0)
415 return -ENODEV;
416
417 /* determine maximum frequency */
418 if (pci_busclk)
419 maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
420 else if (cpu_khz)
421 maxfreq = cpu_khz;
422 else
423 maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
424
425 stock_freq = maxfreq;
426 curfreq = gx_get_cpuspeed(0);
427
428 pr_debug("cpu max frequency is %d.\n", maxfreq);
429 pr_debug("cpu current frequency is %dkHz.\n", curfreq);
430
431 /* setup basic struct for cpufreq API */
432 policy->cpu = 0;
433
434 if (max_duration < POLICY_MIN_DIV)
435 policy->min = maxfreq / max_duration;
436 else
437 policy->min = maxfreq / POLICY_MIN_DIV;
438 policy->max = maxfreq;
439 policy->cur = curfreq;
440 policy->cpuinfo.min_freq = maxfreq / max_duration;
441 policy->cpuinfo.max_freq = maxfreq;
442 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
443
444 return 0;
445}
446
447/*
448 * cpufreq_gx_init:
449 * MediaGX/Geode GX initialize cpufreq driver
450 */
451static struct cpufreq_driver gx_suspmod_driver = {
452 .get = gx_get_cpuspeed,
453 .verify = cpufreq_gx_verify,
454 .target = cpufreq_gx_target,
455 .init = cpufreq_gx_cpu_init,
456 .name = "gx-suspmod",
457 .owner = THIS_MODULE,
458};
459
460static int __init cpufreq_gx_init(void)
461{
462 int ret;
463 struct gxfreq_params *params;
464 struct pci_dev *gx_pci;
465
466 /* Test if we have the right hardware */
467 gx_pci = gx_detect_chipset();
468 if (gx_pci == NULL)
469 return -ENODEV;
470
471 /* check whether module parameters are sane */
472 if (max_duration > 0xff)
473 max_duration = 0xff;
474
475 pr_debug("geode suspend modulation available.\n");
476
477 params = kzalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
478 if (params == NULL)
479 return -ENOMEM;
480
481 params->cs55x0 = gx_pci;
482 gx_params = params;
483
484 /* keep cs55x0 configurations */
485 pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
486 pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
487 pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
488 pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
489 pci_read_config_byte(params->cs55x0, PCI_MODOFF,
490 &(params->off_duration));
491
492 ret = cpufreq_register_driver(&gx_suspmod_driver);
493 if (ret) {
494 kfree(params);
495 return ret; /* register error! */
496 }
497
498 return 0;
499}
500
501static void __exit cpufreq_gx_exit(void)
502{
503 cpufreq_unregister_driver(&gx_suspmod_driver);
504 pci_dev_put(gx_params->cs55x0);
505 kfree(gx_params);
506}
507
508MODULE_AUTHOR("Hiroshi Miura <miura@da-cha.org>");
509MODULE_DESCRIPTION("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
510MODULE_LICENSE("GPL");
511
512module_init(cpufreq_gx_init);
513module_exit(cpufreq_gx_exit);
514
1/*
2 * Cyrix MediaGX and NatSemi Geode Suspend Modulation
3 * (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
4 * (C) 2002 Hiroshi Miura <miura@da-cha.org>
5 * All Rights Reserved
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation
10 *
11 * The author(s) of this software shall not be held liable for damages
12 * of any nature resulting due to the use of this software. This
13 * software is provided AS-IS with no warranties.
14 *
15 * Theoretical note:
16 *
17 * (see Geode(tm) CS5530 manual (rev.4.1) page.56)
18 *
19 * CPU frequency control on NatSemi Geode GX1/GXLV processor and CS55x0
20 * are based on Suspend Modulation.
21 *
22 * Suspend Modulation works by asserting and de-asserting the SUSP# pin
23 * to CPU(GX1/GXLV) for configurable durations. When asserting SUSP#
24 * the CPU enters an idle state. GX1 stops its core clock when SUSP# is
25 * asserted then power consumption is reduced.
26 *
27 * Suspend Modulation's OFF/ON duration are configurable
28 * with 'Suspend Modulation OFF Count Register'
29 * and 'Suspend Modulation ON Count Register'.
30 * These registers are 8bit counters that represent the number of
31 * 32us intervals which the SUSP# pin is asserted(ON)/de-asserted(OFF)
32 * to the processor.
33 *
34 * These counters define a ratio which is the effective frequency
35 * of operation of the system.
36 *
37 * OFF Count
38 * F_eff = Fgx * ----------------------
39 * OFF Count + ON Count
40 *
41 * 0 <= On Count, Off Count <= 255
42 *
43 * From these limits, we can get register values
44 *
45 * off_duration + on_duration <= MAX_DURATION
46 * on_duration = off_duration * (stock_freq - freq) / freq
47 *
48 * off_duration = (freq * DURATION) / stock_freq
49 * on_duration = DURATION - off_duration
50 *
51 *
52 *---------------------------------------------------------------------------
53 *
54 * ChangeLog:
55 * Dec. 12, 2003 Hiroshi Miura <miura@da-cha.org>
56 * - fix on/off register mistake
57 * - fix cpu_khz calc when it stops cpu modulation.
58 *
59 * Dec. 11, 2002 Hiroshi Miura <miura@da-cha.org>
60 * - rewrite for Cyrix MediaGX Cx5510/5520 and
61 * NatSemi Geode Cs5530(A).
62 *
63 * Jul. ??, 2002 Zwane Mwaikambo <zwane@commfireservices.com>
64 * - cs5530_mod patch for 2.4.19-rc1.
65 *
66 *---------------------------------------------------------------------------
67 *
68 * Todo
69 * Test on machines with 5510, 5530, 5530A
70 */
71
72/************************************************************************
73 * Suspend Modulation - Definitions *
74 ************************************************************************/
75
76#include <linux/kernel.h>
77#include <linux/module.h>
78#include <linux/init.h>
79#include <linux/smp.h>
80#include <linux/cpufreq.h>
81#include <linux/pci.h>
82#include <linux/errno.h>
83#include <linux/slab.h>
84
85#include <asm/cpu_device_id.h>
86#include <asm/processor-cyrix.h>
87
88/* PCI config registers, all at F0 */
89#define PCI_PMER1 0x80 /* power management enable register 1 */
90#define PCI_PMER2 0x81 /* power management enable register 2 */
91#define PCI_PMER3 0x82 /* power management enable register 3 */
92#define PCI_IRQTC 0x8c /* irq speedup timer counter register:typical 2 to 4ms */
93#define PCI_VIDTC 0x8d /* video speedup timer counter register: typical 50 to 100ms */
94#define PCI_MODOFF 0x94 /* suspend modulation OFF counter register, 1 = 32us */
95#define PCI_MODON 0x95 /* suspend modulation ON counter register */
96#define PCI_SUSCFG 0x96 /* suspend configuration register */
97
98/* PMER1 bits */
99#define GPM (1<<0) /* global power management */
100#define GIT (1<<1) /* globally enable PM device idle timers */
101#define GTR (1<<2) /* globally enable IO traps */
102#define IRQ_SPDUP (1<<3) /* disable clock throttle during interrupt handling */
103#define VID_SPDUP (1<<4) /* disable clock throttle during vga video handling */
104
105/* SUSCFG bits */
106#define SUSMOD (1<<0) /* enable/disable suspend modulation */
107/* the below is supported only with cs5530 (after rev.1.2)/cs5530A */
108#define SMISPDUP (1<<1) /* select how SMI re-enable suspend modulation: */
109 /* IRQTC timer or read SMI speedup disable reg.(F1BAR[08-09h]) */
110#define SUSCFG (1<<2) /* enable powering down a GXLV processor. "Special 3Volt Suspend" mode */
111/* the below is supported only with cs5530A */
112#define PWRSVE_ISA (1<<3) /* stop ISA clock */
113#define PWRSVE (1<<4) /* active idle */
114
115struct gxfreq_params {
116 u8 on_duration;
117 u8 off_duration;
118 u8 pci_suscfg;
119 u8 pci_pmer1;
120 u8 pci_pmer2;
121 struct pci_dev *cs55x0;
122};
123
124static struct gxfreq_params *gx_params;
125static int stock_freq;
126
127/* PCI bus clock - defaults to 30.000 if cpu_khz is not available */
128static int pci_busclk;
129module_param(pci_busclk, int, 0444);
130
131/* maximum duration for which the cpu may be suspended
132 * (32us * MAX_DURATION). If no parameter is given, this defaults
133 * to 255.
134 * Note that this leads to a maximum of 8 ms(!) where the CPU clock
135 * is suspended -- processing power is just 0.39% of what it used to be,
136 * though. 781.25 kHz(!) for a 200 MHz processor -- wow. */
137static int max_duration = 255;
138module_param(max_duration, int, 0444);
139
140/* For the default policy, we want at least some processing power
141 * - let's say 5%. (min = maxfreq / POLICY_MIN_DIV)
142 */
143#define POLICY_MIN_DIV 20
144
145
146/**
147 * we can detect a core multipiler from dir0_lsb
148 * from GX1 datasheet p.56,
149 * MULT[3:0]:
150 * 0000 = SYSCLK multiplied by 4 (test only)
151 * 0001 = SYSCLK multiplied by 10
152 * 0010 = SYSCLK multiplied by 4
153 * 0011 = SYSCLK multiplied by 6
154 * 0100 = SYSCLK multiplied by 9
155 * 0101 = SYSCLK multiplied by 5
156 * 0110 = SYSCLK multiplied by 7
157 * 0111 = SYSCLK multiplied by 8
158 * of 33.3MHz
159 **/
160static int gx_freq_mult[16] = {
161 4, 10, 4, 6, 9, 5, 7, 8,
162 0, 0, 0, 0, 0, 0, 0, 0
163};
164
165
166/****************************************************************
167 * Low Level chipset interface *
168 ****************************************************************/
169static struct pci_device_id gx_chipset_tbl[] __initdata = {
170 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY), },
171 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5520), },
172 { PCI_VDEVICE(CYRIX, PCI_DEVICE_ID_CYRIX_5510), },
173 { 0, },
174};
175MODULE_DEVICE_TABLE(pci, gx_chipset_tbl);
176
177static void gx_write_byte(int reg, int value)
178{
179 pci_write_config_byte(gx_params->cs55x0, reg, value);
180}
181
182/**
183 * gx_detect_chipset:
184 *
185 **/
186static __init struct pci_dev *gx_detect_chipset(void)
187{
188 struct pci_dev *gx_pci = NULL;
189
190 /* detect which companion chip is used */
191 for_each_pci_dev(gx_pci) {
192 if ((pci_match_id(gx_chipset_tbl, gx_pci)) != NULL)
193 return gx_pci;
194 }
195
196 pr_debug("error: no supported chipset found!\n");
197 return NULL;
198}
199
200/**
201 * gx_get_cpuspeed:
202 *
203 * Finds out at which efficient frequency the Cyrix MediaGX/NatSemi
204 * Geode CPU runs.
205 */
206static unsigned int gx_get_cpuspeed(unsigned int cpu)
207{
208 if ((gx_params->pci_suscfg & SUSMOD) == 0)
209 return stock_freq;
210
211 return (stock_freq * gx_params->off_duration)
212 / (gx_params->on_duration + gx_params->off_duration);
213}
214
215/**
216 * gx_validate_speed:
217 * determine current cpu speed
218 *
219 **/
220
221static unsigned int gx_validate_speed(unsigned int khz, u8 *on_duration,
222 u8 *off_duration)
223{
224 unsigned int i;
225 u8 tmp_on, tmp_off;
226 int old_tmp_freq = stock_freq;
227 int tmp_freq;
228
229 *off_duration = 1;
230 *on_duration = 0;
231
232 for (i = max_duration; i > 0; i--) {
233 tmp_off = ((khz * i) / stock_freq) & 0xff;
234 tmp_on = i - tmp_off;
235 tmp_freq = (stock_freq * tmp_off) / i;
236 /* if this relation is closer to khz, use this. If it's equal,
237 * prefer it, too - lower latency */
238 if (abs(tmp_freq - khz) <= abs(old_tmp_freq - khz)) {
239 *on_duration = tmp_on;
240 *off_duration = tmp_off;
241 old_tmp_freq = tmp_freq;
242 }
243 }
244
245 return old_tmp_freq;
246}
247
248
249/**
250 * gx_set_cpuspeed:
251 * set cpu speed in khz.
252 **/
253
254static void gx_set_cpuspeed(unsigned int khz)
255{
256 u8 suscfg, pmer1;
257 unsigned int new_khz;
258 unsigned long flags;
259 struct cpufreq_freqs freqs;
260
261 freqs.cpu = 0;
262 freqs.old = gx_get_cpuspeed(0);
263
264 new_khz = gx_validate_speed(khz, &gx_params->on_duration,
265 &gx_params->off_duration);
266
267 freqs.new = new_khz;
268
269 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
270 local_irq_save(flags);
271
272
273
274 if (new_khz != stock_freq) {
275 /* if new khz == 100% of CPU speed, it is special case */
276 switch (gx_params->cs55x0->device) {
277 case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
278 pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
279 /* FIXME: need to test other values -- Zwane,Miura */
280 /* typical 2 to 4ms */
281 gx_write_byte(PCI_IRQTC, 4);
282 /* typical 50 to 100ms */
283 gx_write_byte(PCI_VIDTC, 100);
284 gx_write_byte(PCI_PMER1, pmer1);
285
286 if (gx_params->cs55x0->revision < 0x10) {
287 /* CS5530(rev 1.2, 1.3) */
288 suscfg = gx_params->pci_suscfg|SUSMOD;
289 } else {
290 /* CS5530A,B.. */
291 suscfg = gx_params->pci_suscfg|SUSMOD|PWRSVE;
292 }
293 break;
294 case PCI_DEVICE_ID_CYRIX_5520:
295 case PCI_DEVICE_ID_CYRIX_5510:
296 suscfg = gx_params->pci_suscfg | SUSMOD;
297 break;
298 default:
299 local_irq_restore(flags);
300 pr_debug("fatal: try to set unknown chipset.\n");
301 return;
302 }
303 } else {
304 suscfg = gx_params->pci_suscfg & ~(SUSMOD);
305 gx_params->off_duration = 0;
306 gx_params->on_duration = 0;
307 pr_debug("suspend modulation disabled: cpu runs 100%% speed.\n");
308 }
309
310 gx_write_byte(PCI_MODOFF, gx_params->off_duration);
311 gx_write_byte(PCI_MODON, gx_params->on_duration);
312
313 gx_write_byte(PCI_SUSCFG, suscfg);
314 pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);
315
316 local_irq_restore(flags);
317
318 gx_params->pci_suscfg = suscfg;
319
320 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
321
322 pr_debug("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
323 gx_params->on_duration * 32, gx_params->off_duration * 32);
324 pr_debug("suspend modulation w/ clock speed: %d kHz.\n", freqs.new);
325}
326
327/****************************************************************
328 * High level functions *
329 ****************************************************************/
330
331/*
332 * cpufreq_gx_verify: test if frequency range is valid
333 *
334 * This function checks if a given frequency range in kHz is valid
335 * for the hardware supported by the driver.
336 */
337
338static int cpufreq_gx_verify(struct cpufreq_policy *policy)
339{
340 unsigned int tmp_freq = 0;
341 u8 tmp1, tmp2;
342
343 if (!stock_freq || !policy)
344 return -EINVAL;
345
346 policy->cpu = 0;
347 cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
348 stock_freq);
349
350 /* it needs to be assured that at least one supported frequency is
351 * within policy->min and policy->max. If it is not, policy->max
352 * needs to be increased until one freuqency is supported.
353 * policy->min may not be decreased, though. This way we guarantee a
354 * specific processing capacity.
355 */
356 tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
357 if (tmp_freq < policy->min)
358 tmp_freq += stock_freq / max_duration;
359 policy->min = tmp_freq;
360 if (policy->min > policy->max)
361 policy->max = tmp_freq;
362 tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
363 if (tmp_freq > policy->max)
364 tmp_freq -= stock_freq / max_duration;
365 policy->max = tmp_freq;
366 if (policy->max < policy->min)
367 policy->max = policy->min;
368 cpufreq_verify_within_limits(policy, (stock_freq / max_duration),
369 stock_freq);
370
371 return 0;
372}
373
374/*
375 * cpufreq_gx_target:
376 *
377 */
378static int cpufreq_gx_target(struct cpufreq_policy *policy,
379 unsigned int target_freq,
380 unsigned int relation)
381{
382 u8 tmp1, tmp2;
383 unsigned int tmp_freq;
384
385 if (!stock_freq || !policy)
386 return -EINVAL;
387
388 policy->cpu = 0;
389
390 tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
391 while (tmp_freq < policy->min) {
392 tmp_freq += stock_freq / max_duration;
393 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
394 }
395 while (tmp_freq > policy->max) {
396 tmp_freq -= stock_freq / max_duration;
397 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
398 }
399
400 gx_set_cpuspeed(tmp_freq);
401
402 return 0;
403}
404
405static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
406{
407 unsigned int maxfreq, curfreq;
408
409 if (!policy || policy->cpu != 0)
410 return -ENODEV;
411
412 /* determine maximum frequency */
413 if (pci_busclk)
414 maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
415 else if (cpu_khz)
416 maxfreq = cpu_khz;
417 else
418 maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
419
420 stock_freq = maxfreq;
421 curfreq = gx_get_cpuspeed(0);
422
423 pr_debug("cpu max frequency is %d.\n", maxfreq);
424 pr_debug("cpu current frequency is %dkHz.\n", curfreq);
425
426 /* setup basic struct for cpufreq API */
427 policy->cpu = 0;
428
429 if (max_duration < POLICY_MIN_DIV)
430 policy->min = maxfreq / max_duration;
431 else
432 policy->min = maxfreq / POLICY_MIN_DIV;
433 policy->max = maxfreq;
434 policy->cur = curfreq;
435 policy->cpuinfo.min_freq = maxfreq / max_duration;
436 policy->cpuinfo.max_freq = maxfreq;
437 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
438
439 return 0;
440}
441
442/*
443 * cpufreq_gx_init:
444 * MediaGX/Geode GX initialize cpufreq driver
445 */
446static struct cpufreq_driver gx_suspmod_driver = {
447 .get = gx_get_cpuspeed,
448 .verify = cpufreq_gx_verify,
449 .target = cpufreq_gx_target,
450 .init = cpufreq_gx_cpu_init,
451 .name = "gx-suspmod",
452 .owner = THIS_MODULE,
453};
454
455static int __init cpufreq_gx_init(void)
456{
457 int ret;
458 struct gxfreq_params *params;
459 struct pci_dev *gx_pci;
460
461 /* Test if we have the right hardware */
462 gx_pci = gx_detect_chipset();
463 if (gx_pci == NULL)
464 return -ENODEV;
465
466 /* check whether module parameters are sane */
467 if (max_duration > 0xff)
468 max_duration = 0xff;
469
470 pr_debug("geode suspend modulation available.\n");
471
472 params = kzalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
473 if (params == NULL)
474 return -ENOMEM;
475
476 params->cs55x0 = gx_pci;
477 gx_params = params;
478
479 /* keep cs55x0 configurations */
480 pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
481 pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
482 pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
483 pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
484 pci_read_config_byte(params->cs55x0, PCI_MODOFF,
485 &(params->off_duration));
486
487 ret = cpufreq_register_driver(&gx_suspmod_driver);
488 if (ret) {
489 kfree(params);
490 return ret; /* register error! */
491 }
492
493 return 0;
494}
495
496static void __exit cpufreq_gx_exit(void)
497{
498 cpufreq_unregister_driver(&gx_suspmod_driver);
499 pci_dev_put(gx_params->cs55x0);
500 kfree(gx_params);
501}
502
503MODULE_AUTHOR("Hiroshi Miura <miura@da-cha.org>");
504MODULE_DESCRIPTION("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
505MODULE_LICENSE("GPL");
506
507module_init(cpufreq_gx_init);
508module_exit(cpufreq_gx_exit);
509