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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/gx-suspmod.c')
-rw-r--r--arch/i386/kernel/cpu/cpufreq/gx-suspmod.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c b/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
new file mode 100644
index 000000000000..1a49adb1f4a6
--- /dev/null
+++ b/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
@@ -0,0 +1,502 @@
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 * Theoritical 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 Moduration.
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 <asm/processor.h>
83#include <asm/errno.h>
84
85/* PCI config registers, all at F0 */
86#define PCI_PMER1 0x80 /* power management enable register 1 */
87#define PCI_PMER2 0x81 /* power management enable register 2 */
88#define PCI_PMER3 0x82 /* power management enable register 3 */
89#define PCI_IRQTC 0x8c /* irq speedup timer counter register:typical 2 to 4ms */
90#define PCI_VIDTC 0x8d /* video speedup timer counter register: typical 50 to 100ms */
91#define PCI_MODOFF 0x94 /* suspend modulation OFF counter register, 1 = 32us */
92#define PCI_MODON 0x95 /* suspend modulation ON counter register */
93#define PCI_SUSCFG 0x96 /* suspend configuration register */
94
95/* PMER1 bits */
96#define GPM (1<<0) /* global power management */
97#define GIT (1<<1) /* globally enable PM device idle timers */
98#define GTR (1<<2) /* globally enable IO traps */
99#define IRQ_SPDUP (1<<3) /* disable clock throttle during interrupt handling */
100#define VID_SPDUP (1<<4) /* disable clock throttle during vga video handling */
101
102/* SUSCFG bits */
103#define SUSMOD (1<<0) /* enable/disable suspend modulation */
104/* the belows support only with cs5530 (after rev.1.2)/cs5530A */
105#define SMISPDUP (1<<1) /* select how SMI re-enable suspend modulation: */
106 /* IRQTC timer or read SMI speedup disable reg.(F1BAR[08-09h]) */
107#define SUSCFG (1<<2) /* enable powering down a GXLV processor. "Special 3Volt Suspend" mode */
108/* the belows support only with cs5530A */
109#define PWRSVE_ISA (1<<3) /* stop ISA clock */
110#define PWRSVE (1<<4) /* active idle */
111
112struct gxfreq_params {
113 u8 on_duration;
114 u8 off_duration;
115 u8 pci_suscfg;
116 u8 pci_pmer1;
117 u8 pci_pmer2;
118 u8 pci_rev;
119 struct pci_dev *cs55x0;
120};
121
122static struct gxfreq_params *gx_params;
123static int stock_freq;
124
125/* PCI bus clock - defaults to 30.000 if cpu_khz is not available */
126static int pci_busclk = 0;
127module_param (pci_busclk, int, 0444);
128
129/* maximum duration for which the cpu may be suspended
130 * (32us * MAX_DURATION). If no parameter is given, this defaults
131 * to 255.
132 * Note that this leads to a maximum of 8 ms(!) where the CPU clock
133 * is suspended -- processing power is just 0.39% of what it used to be,
134 * though. 781.25 kHz(!) for a 200 MHz processor -- wow. */
135static int max_duration = 255;
136module_param (max_duration, int, 0444);
137
138/* For the default policy, we want at least some processing power
139 * - let's say 5%. (min = maxfreq / POLICY_MIN_DIV)
140 */
141#define POLICY_MIN_DIV 20
142
143
144#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "gx-suspmod", msg)
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_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, PCI_ANY_ID, PCI_ANY_ID },
171 { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5520, PCI_ANY_ID, PCI_ANY_ID },
172 { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5510, PCI_ANY_ID, PCI_ANY_ID },
173 { 0, },
174};
175
176/**
177 * gx_detect_chipset:
178 *
179 **/
180static __init struct pci_dev *gx_detect_chipset(void)
181{
182 struct pci_dev *gx_pci = NULL;
183
184 /* check if CPU is a MediaGX or a Geode. */
185 if ((current_cpu_data.x86_vendor != X86_VENDOR_NSC) &&
186 (current_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
187 dprintk("error: no MediaGX/Geode processor found!\n");
188 return NULL;
189 }
190
191 /* detect which companion chip is used */
192 while ((gx_pci = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, gx_pci)) != NULL) {
193 if ((pci_match_device (gx_chipset_tbl, gx_pci)) != NULL) {
194 return gx_pci;
195 }
196 }
197
198 dprintk("error: no supported chipset found!\n");
199 return NULL;
200}
201
202/**
203 * gx_get_cpuspeed:
204 *
205 * Finds out at which efficient frequency the Cyrix MediaGX/NatSemi Geode CPU runs.
206 */
207static unsigned int gx_get_cpuspeed(unsigned int cpu)
208{
209 if ((gx_params->pci_suscfg & SUSMOD) == 0)
210 return stock_freq;
211
212 return (stock_freq * gx_params->off_duration)
213 / (gx_params->on_duration + gx_params->off_duration);
214}
215
216/**
217 * gx_validate_speed:
218 * determine current cpu speed
219 *
220**/
221
222static unsigned int gx_validate_speed(unsigned int khz, u8 *on_duration, 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
262 freqs.cpu = 0;
263 freqs.old = gx_get_cpuspeed(0);
264
265 new_khz = gx_validate_speed(khz, &gx_params->on_duration, &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 if (new_khz != stock_freq) { /* if new khz == 100% of CPU speed, it is special case */
273 switch (gx_params->cs55x0->device) {
274 case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
275 pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
276 /* FIXME: need to test other values -- Zwane,Miura */
277 pci_write_config_byte(gx_params->cs55x0, PCI_IRQTC, 4); /* typical 2 to 4ms */
278 pci_write_config_byte(gx_params->cs55x0, PCI_VIDTC, 100);/* typical 50 to 100ms */
279 pci_write_config_byte(gx_params->cs55x0, PCI_PMER1, pmer1);
280
281 if (gx_params->pci_rev < 0x10) { /* CS5530(rev 1.2, 1.3) */
282 suscfg = gx_params->pci_suscfg | SUSMOD;
283 } else { /* CS5530A,B.. */
284 suscfg = gx_params->pci_suscfg | SUSMOD | PWRSVE;
285 }
286 break;
287 case PCI_DEVICE_ID_CYRIX_5520:
288 case PCI_DEVICE_ID_CYRIX_5510:
289 suscfg = gx_params->pci_suscfg | SUSMOD;
290 break;
291 default:
292 local_irq_restore(flags);
293 dprintk("fatal: try to set unknown chipset.\n");
294 return;
295 }
296 } else {
297 suscfg = gx_params->pci_suscfg & ~(SUSMOD);
298 gx_params->off_duration = 0;
299 gx_params->on_duration = 0;
300 dprintk("suspend modulation disabled: cpu runs 100 percent speed.\n");
301 }
302
303 pci_write_config_byte(gx_params->cs55x0, PCI_MODOFF, gx_params->off_duration);
304 pci_write_config_byte(gx_params->cs55x0, PCI_MODON, gx_params->on_duration);
305
306 pci_write_config_byte(gx_params->cs55x0, PCI_SUSCFG, suscfg);
307 pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);
308
309 local_irq_restore(flags);
310
311 gx_params->pci_suscfg = suscfg;
312
313 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
314
315 dprintk("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
316 gx_params->on_duration * 32, gx_params->off_duration * 32);
317 dprintk("suspend modulation w/ clock speed: %d kHz.\n", freqs.new);
318}
319
320/****************************************************************
321 * High level functions *
322 ****************************************************************/
323
324/*
325 * cpufreq_gx_verify: test if frequency range is valid
326 *
327 * This function checks if a given frequency range in kHz is valid
328 * for the hardware supported by the driver.
329 */
330
331static int cpufreq_gx_verify(struct cpufreq_policy *policy)
332{
333 unsigned int tmp_freq = 0;
334 u8 tmp1, tmp2;
335
336 if (!stock_freq || !policy)
337 return -EINVAL;
338
339 policy->cpu = 0;
340 cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);
341
342 /* it needs to be assured that at least one supported frequency is
343 * within policy->min and policy->max. If it is not, policy->max
344 * needs to be increased until one freuqency is supported.
345 * policy->min may not be decreased, though. This way we guarantee a
346 * specific processing capacity.
347 */
348 tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
349 if (tmp_freq < policy->min)
350 tmp_freq += stock_freq / max_duration;
351 policy->min = tmp_freq;
352 if (policy->min > policy->max)
353 policy->max = tmp_freq;
354 tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
355 if (tmp_freq > policy->max)
356 tmp_freq -= stock_freq / max_duration;
357 policy->max = tmp_freq;
358 if (policy->max < policy->min)
359 policy->max = policy->min;
360 cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);
361
362 return 0;
363}
364
365/*
366 * cpufreq_gx_target:
367 *
368 */
369static int cpufreq_gx_target(struct cpufreq_policy *policy,
370 unsigned int target_freq,
371 unsigned int relation)
372{
373 u8 tmp1, tmp2;
374 unsigned int tmp_freq;
375
376 if (!stock_freq || !policy)
377 return -EINVAL;
378
379 policy->cpu = 0;
380
381 tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
382 while (tmp_freq < policy->min) {
383 tmp_freq += stock_freq / max_duration;
384 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
385 }
386 while (tmp_freq > policy->max) {
387 tmp_freq -= stock_freq / max_duration;
388 tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
389 }
390
391 gx_set_cpuspeed(tmp_freq);
392
393 return 0;
394}
395
396static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
397{
398 unsigned int maxfreq, curfreq;
399
400 if (!policy || policy->cpu != 0)
401 return -ENODEV;
402
403 /* determine maximum frequency */
404 if (pci_busclk) {
405 maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
406 } else if (cpu_khz) {
407 maxfreq = cpu_khz;
408 } else {
409 maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
410 }
411 stock_freq = maxfreq;
412 curfreq = gx_get_cpuspeed(0);
413
414 dprintk("cpu max frequency is %d.\n", maxfreq);
415 dprintk("cpu current frequency is %dkHz.\n",curfreq);
416
417 /* setup basic struct for cpufreq API */
418 policy->cpu = 0;
419
420 if (max_duration < POLICY_MIN_DIV)
421 policy->min = maxfreq / max_duration;
422 else
423 policy->min = maxfreq / POLICY_MIN_DIV;
424 policy->max = maxfreq;
425 policy->cur = curfreq;
426 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
427 policy->cpuinfo.min_freq = maxfreq / max_duration;
428 policy->cpuinfo.max_freq = maxfreq;
429 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
430
431 return 0;
432}
433
434/*
435 * cpufreq_gx_init:
436 * MediaGX/Geode GX initialize cpufreq driver
437 */
438static struct cpufreq_driver gx_suspmod_driver = {
439 .get = gx_get_cpuspeed,
440 .verify = cpufreq_gx_verify,
441 .target = cpufreq_gx_target,
442 .init = cpufreq_gx_cpu_init,
443 .name = "gx-suspmod",
444 .owner = THIS_MODULE,
445};
446
447static int __init cpufreq_gx_init(void)
448{
449 int ret;
450 struct gxfreq_params *params;
451 struct pci_dev *gx_pci;
452 u32 class_rev;
453
454 /* Test if we have the right hardware */
455 if ((gx_pci = gx_detect_chipset()) == NULL)
456 return -ENODEV;
457
458 /* check whether module parameters are sane */
459 if (max_duration > 0xff)
460 max_duration = 0xff;
461
462 dprintk("geode suspend modulation available.\n");
463
464 params = kmalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
465 if (params == NULL)
466 return -ENOMEM;
467 memset(params, 0, sizeof(struct gxfreq_params));
468
469 params->cs55x0 = gx_pci;
470 gx_params = params;
471
472 /* keep cs55x0 configurations */
473 pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
474 pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
475 pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
476 pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
477 pci_read_config_byte(params->cs55x0, PCI_MODOFF, &(params->off_duration));
478 pci_read_config_dword(params->cs55x0, PCI_CLASS_REVISION, &class_rev);
479 params->pci_rev = class_rev && 0xff;
480
481 if ((ret = cpufreq_register_driver(&gx_suspmod_driver))) {
482 kfree(params);
483 return ret; /* register error! */
484 }
485
486 return 0;
487}
488
489static void __exit cpufreq_gx_exit(void)
490{
491 cpufreq_unregister_driver(&gx_suspmod_driver);
492 pci_dev_put(gx_params->cs55x0);
493 kfree(gx_params);
494}
495
496MODULE_AUTHOR ("Hiroshi Miura <miura@da-cha.org>");
497MODULE_DESCRIPTION ("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
498MODULE_LICENSE ("GPL");
499
500module_init(cpufreq_gx_init);
501module_exit(cpufreq_gx_exit);
502