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1da177e4 LT |
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 | ||
112 | struct 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 | ||
122 | static struct gxfreq_params *gx_params; | |
123 | static int stock_freq; | |
124 | ||
125 | /* PCI bus clock - defaults to 30.000 if cpu_khz is not available */ | |
126 | static int pci_busclk = 0; | |
127 | module_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. */ | |
135 | static int max_duration = 255; | |
136 | module_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 | **/ | |
160 | static 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 | ****************************************************************/ | |
169 | static 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 | **/ | |
180 | static __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 | */ | |
207 | static 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 | ||
222 | static 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 | ||
254 | static 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 | ||
331 | static 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 | */ | |
369 | static 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 | ||
396 | static 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 | */ | |
438 | static 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 | ||
447 | static 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 | ||
489 | static 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 | ||
496 | MODULE_AUTHOR ("Hiroshi Miura <miura@da-cha.org>"); | |
497 | MODULE_DESCRIPTION ("Cpufreq driver for Cyrix MediaGX and NatSemi Geode"); | |
498 | MODULE_LICENSE ("GPL"); | |
499 | ||
500 | module_init(cpufreq_gx_init); | |
501 | module_exit(cpufreq_gx_exit); | |
502 |