xref: /linux/drivers/cpufreq/pmac64-cpufreq.c (revision 9c0ebcf78fde0ffa348a95a544c6d3f2dac5af65)
1 /*
2  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
3  *  and                       Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  * This driver adds basic cpufreq support for SMU & 970FX based G5 Macs,
10  * that is iMac G5 and latest single CPU desktop.
11  */
12 
13 #undef DEBUG
14 
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/errno.h>
18 #include <linux/kernel.h>
19 #include <linux/delay.h>
20 #include <linux/sched.h>
21 #include <linux/cpufreq.h>
22 #include <linux/init.h>
23 #include <linux/completion.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <asm/prom.h>
27 #include <asm/machdep.h>
28 #include <asm/irq.h>
29 #include <asm/sections.h>
30 #include <asm/cputable.h>
31 #include <asm/time.h>
32 #include <asm/smu.h>
33 #include <asm/pmac_pfunc.h>
34 
35 #define DBG(fmt...) pr_debug(fmt)
36 
37 /* see 970FX user manual */
38 
39 #define SCOM_PCR 0x0aa001			/* PCR scom addr */
40 
41 #define PCR_HILO_SELECT		0x80000000U	/* 1 = PCR, 0 = PCRH */
42 #define PCR_SPEED_FULL		0x00000000U	/* 1:1 speed value */
43 #define PCR_SPEED_HALF		0x00020000U	/* 1:2 speed value */
44 #define PCR_SPEED_QUARTER	0x00040000U	/* 1:4 speed value */
45 #define PCR_SPEED_MASK		0x000e0000U	/* speed mask */
46 #define PCR_SPEED_SHIFT		17
47 #define PCR_FREQ_REQ_VALID	0x00010000U	/* freq request valid */
48 #define PCR_VOLT_REQ_VALID	0x00008000U	/* volt request valid */
49 #define PCR_TARGET_TIME_MASK	0x00006000U	/* target time */
50 #define PCR_STATLAT_MASK	0x00001f00U	/* STATLAT value */
51 #define PCR_SNOOPLAT_MASK	0x000000f0U	/* SNOOPLAT value */
52 #define PCR_SNOOPACC_MASK	0x0000000fU	/* SNOOPACC value */
53 
54 #define SCOM_PSR 0x408001			/* PSR scom addr */
55 /* warning: PSR is a 64 bits register */
56 #define PSR_CMD_RECEIVED	0x2000000000000000U   /* command received */
57 #define PSR_CMD_COMPLETED	0x1000000000000000U   /* command completed */
58 #define PSR_CUR_SPEED_MASK	0x0300000000000000U   /* current speed */
59 #define PSR_CUR_SPEED_SHIFT	(56)
60 
61 /*
62  * The G5 only supports two frequencies (Quarter speed is not supported)
63  */
64 #define CPUFREQ_HIGH                  0
65 #define CPUFREQ_LOW                   1
66 
67 static struct cpufreq_frequency_table g5_cpu_freqs[] = {
68 	{CPUFREQ_HIGH, 		0},
69 	{CPUFREQ_LOW,		0},
70 	{0,			CPUFREQ_TABLE_END},
71 };
72 
73 /* Power mode data is an array of the 32 bits PCR values to use for
74  * the various frequencies, retrieved from the device-tree
75  */
76 static int g5_pmode_cur;
77 
78 static void (*g5_switch_volt)(int speed_mode);
79 static int (*g5_switch_freq)(int speed_mode);
80 static int (*g5_query_freq)(void);
81 
82 static DEFINE_MUTEX(g5_switch_mutex);
83 
84 static unsigned long transition_latency;
85 
86 #ifdef CONFIG_PMAC_SMU
87 
88 static const u32 *g5_pmode_data;
89 static int g5_pmode_max;
90 
91 static struct smu_sdbp_fvt *g5_fvt_table;	/* table of op. points */
92 static int g5_fvt_count;			/* number of op. points */
93 static int g5_fvt_cur;				/* current op. point */
94 
95 /*
96  * SMU based voltage switching for Neo2 platforms
97  */
98 
99 static void g5_smu_switch_volt(int speed_mode)
100 {
101 	struct smu_simple_cmd	cmd;
102 
103 	DECLARE_COMPLETION_ONSTACK(comp);
104 	smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
105 			 &comp, 'V', 'S', 'L', 'E', 'W',
106 			 0xff, g5_fvt_cur+1, speed_mode);
107 	wait_for_completion(&comp);
108 }
109 
110 /*
111  * Platform function based voltage/vdnap switching for Neo2
112  */
113 
114 static struct pmf_function *pfunc_set_vdnap0;
115 static struct pmf_function *pfunc_vdnap0_complete;
116 
117 static void g5_vdnap_switch_volt(int speed_mode)
118 {
119 	struct pmf_args args;
120 	u32 slew, done = 0;
121 	unsigned long timeout;
122 
123 	slew = (speed_mode == CPUFREQ_LOW) ? 1 : 0;
124 	args.count = 1;
125 	args.u[0].p = &slew;
126 
127 	pmf_call_one(pfunc_set_vdnap0, &args);
128 
129 	/* It's an irq GPIO so we should be able to just block here,
130 	 * I'll do that later after I've properly tested the IRQ code for
131 	 * platform functions
132 	 */
133 	timeout = jiffies + HZ/10;
134 	while(!time_after(jiffies, timeout)) {
135 		args.count = 1;
136 		args.u[0].p = &done;
137 		pmf_call_one(pfunc_vdnap0_complete, &args);
138 		if (done)
139 			break;
140 		usleep_range(1000, 1000);
141 	}
142 	if (done == 0)
143 		printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
144 }
145 
146 
147 /*
148  * SCOM based frequency switching for 970FX rev3
149  */
150 static int g5_scom_switch_freq(int speed_mode)
151 {
152 	unsigned long flags;
153 	int to;
154 
155 	/* If frequency is going up, first ramp up the voltage */
156 	if (speed_mode < g5_pmode_cur)
157 		g5_switch_volt(speed_mode);
158 
159 	local_irq_save(flags);
160 
161 	/* Clear PCR high */
162 	scom970_write(SCOM_PCR, 0);
163 	/* Clear PCR low */
164        	scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
165 	/* Set PCR low */
166 	scom970_write(SCOM_PCR, PCR_HILO_SELECT |
167 		      g5_pmode_data[speed_mode]);
168 
169 	/* Wait for completion */
170 	for (to = 0; to < 10; to++) {
171 		unsigned long psr = scom970_read(SCOM_PSR);
172 
173 		if ((psr & PSR_CMD_RECEIVED) == 0 &&
174 		    (((psr >> PSR_CUR_SPEED_SHIFT) ^
175 		      (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
176 		    == 0)
177 			break;
178 		if (psr & PSR_CMD_COMPLETED)
179 			break;
180 		udelay(100);
181 	}
182 
183 	local_irq_restore(flags);
184 
185 	/* If frequency is going down, last ramp the voltage */
186 	if (speed_mode > g5_pmode_cur)
187 		g5_switch_volt(speed_mode);
188 
189 	g5_pmode_cur = speed_mode;
190 	ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
191 
192 	return 0;
193 }
194 
195 static int g5_scom_query_freq(void)
196 {
197 	unsigned long psr = scom970_read(SCOM_PSR);
198 	int i;
199 
200 	for (i = 0; i <= g5_pmode_max; i++)
201 		if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
202 		      (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
203 			break;
204 	return i;
205 }
206 
207 /*
208  * Fake voltage switching for platforms with missing support
209  */
210 
211 static void g5_dummy_switch_volt(int speed_mode)
212 {
213 }
214 
215 #endif /* CONFIG_PMAC_SMU */
216 
217 /*
218  * Platform function based voltage switching for PowerMac7,2 & 7,3
219  */
220 
221 static struct pmf_function *pfunc_cpu0_volt_high;
222 static struct pmf_function *pfunc_cpu0_volt_low;
223 static struct pmf_function *pfunc_cpu1_volt_high;
224 static struct pmf_function *pfunc_cpu1_volt_low;
225 
226 static void g5_pfunc_switch_volt(int speed_mode)
227 {
228 	if (speed_mode == CPUFREQ_HIGH) {
229 		if (pfunc_cpu0_volt_high)
230 			pmf_call_one(pfunc_cpu0_volt_high, NULL);
231 		if (pfunc_cpu1_volt_high)
232 			pmf_call_one(pfunc_cpu1_volt_high, NULL);
233 	} else {
234 		if (pfunc_cpu0_volt_low)
235 			pmf_call_one(pfunc_cpu0_volt_low, NULL);
236 		if (pfunc_cpu1_volt_low)
237 			pmf_call_one(pfunc_cpu1_volt_low, NULL);
238 	}
239 	usleep_range(10000, 10000); /* should be faster , to fix */
240 }
241 
242 /*
243  * Platform function based frequency switching for PowerMac7,2 & 7,3
244  */
245 
246 static struct pmf_function *pfunc_cpu_setfreq_high;
247 static struct pmf_function *pfunc_cpu_setfreq_low;
248 static struct pmf_function *pfunc_cpu_getfreq;
249 static struct pmf_function *pfunc_slewing_done;
250 
251 static int g5_pfunc_switch_freq(int speed_mode)
252 {
253 	struct pmf_args args;
254 	u32 done = 0;
255 	unsigned long timeout;
256 	int rc;
257 
258 	DBG("g5_pfunc_switch_freq(%d)\n", speed_mode);
259 
260 	/* If frequency is going up, first ramp up the voltage */
261 	if (speed_mode < g5_pmode_cur)
262 		g5_switch_volt(speed_mode);
263 
264 	/* Do it */
265 	if (speed_mode == CPUFREQ_HIGH)
266 		rc = pmf_call_one(pfunc_cpu_setfreq_high, NULL);
267 	else
268 		rc = pmf_call_one(pfunc_cpu_setfreq_low, NULL);
269 
270 	if (rc)
271 		printk(KERN_WARNING "cpufreq: pfunc switch error %d\n", rc);
272 
273 	/* It's an irq GPIO so we should be able to just block here,
274 	 * I'll do that later after I've properly tested the IRQ code for
275 	 * platform functions
276 	 */
277 	timeout = jiffies + HZ/10;
278 	while(!time_after(jiffies, timeout)) {
279 		args.count = 1;
280 		args.u[0].p = &done;
281 		pmf_call_one(pfunc_slewing_done, &args);
282 		if (done)
283 			break;
284 		usleep_range(500, 500);
285 	}
286 	if (done == 0)
287 		printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
288 
289 	/* If frequency is going down, last ramp the voltage */
290 	if (speed_mode > g5_pmode_cur)
291 		g5_switch_volt(speed_mode);
292 
293 	g5_pmode_cur = speed_mode;
294 	ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
295 
296 	return 0;
297 }
298 
299 static int g5_pfunc_query_freq(void)
300 {
301 	struct pmf_args args;
302 	u32 val = 0;
303 
304 	args.count = 1;
305 	args.u[0].p = &val;
306 	pmf_call_one(pfunc_cpu_getfreq, &args);
307 	return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
308 }
309 
310 
311 /*
312  * Common interface to the cpufreq core
313  */
314 
315 static int g5_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
316 {
317 	struct cpufreq_freqs freqs;
318 	int rc;
319 
320 	mutex_lock(&g5_switch_mutex);
321 
322 	freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
323 	freqs.new = g5_cpu_freqs[index].frequency;
324 
325 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
326 	rc = g5_switch_freq(index);
327 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
328 
329 	mutex_unlock(&g5_switch_mutex);
330 
331 	return rc;
332 }
333 
334 static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
335 {
336 	return g5_cpu_freqs[g5_pmode_cur].frequency;
337 }
338 
339 static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
340 {
341 	return cpufreq_generic_init(policy, g5_cpu_freqs, transition_latency);
342 }
343 
344 static struct cpufreq_driver g5_cpufreq_driver = {
345 	.name		= "powermac",
346 	.flags		= CPUFREQ_CONST_LOOPS,
347 	.init		= g5_cpufreq_cpu_init,
348 	.verify		= cpufreq_generic_frequency_table_verify,
349 	.target_index	= g5_cpufreq_target,
350 	.get		= g5_cpufreq_get_speed,
351 	.attr 		= cpufreq_generic_attr,
352 };
353 
354 
355 #ifdef CONFIG_PMAC_SMU
356 
357 static int __init g5_neo2_cpufreq_init(struct device_node *cpunode)
358 {
359 	unsigned int psize, ssize;
360 	unsigned long max_freq;
361 	char *freq_method, *volt_method;
362 	const u32 *valp;
363 	u32 pvr_hi;
364 	int use_volts_vdnap = 0;
365 	int use_volts_smu = 0;
366 	int rc = -ENODEV;
367 
368 	/* Check supported platforms */
369 	if (of_machine_is_compatible("PowerMac8,1") ||
370 	    of_machine_is_compatible("PowerMac8,2") ||
371 	    of_machine_is_compatible("PowerMac9,1") ||
372 	    of_machine_is_compatible("PowerMac12,1"))
373 		use_volts_smu = 1;
374 	else if (of_machine_is_compatible("PowerMac11,2"))
375 		use_volts_vdnap = 1;
376 	else
377 		return -ENODEV;
378 
379 	/* Check 970FX for now */
380 	valp = of_get_property(cpunode, "cpu-version", NULL);
381 	if (!valp) {
382 		DBG("No cpu-version property !\n");
383 		goto bail_noprops;
384 	}
385 	pvr_hi = (*valp) >> 16;
386 	if (pvr_hi != 0x3c && pvr_hi != 0x44) {
387 		printk(KERN_ERR "cpufreq: Unsupported CPU version\n");
388 		goto bail_noprops;
389 	}
390 
391 	/* Look for the powertune data in the device-tree */
392 	g5_pmode_data = of_get_property(cpunode, "power-mode-data",&psize);
393 	if (!g5_pmode_data) {
394 		DBG("No power-mode-data !\n");
395 		goto bail_noprops;
396 	}
397 	g5_pmode_max = psize / sizeof(u32) - 1;
398 
399 	if (use_volts_smu) {
400 		const struct smu_sdbp_header *shdr;
401 
402 		/* Look for the FVT table */
403 		shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
404 		if (!shdr)
405 			goto bail_noprops;
406 		g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
407 		ssize = (shdr->len * sizeof(u32)) - sizeof(*shdr);
408 		g5_fvt_count = ssize / sizeof(*g5_fvt_table);
409 		g5_fvt_cur = 0;
410 
411 		/* Sanity checking */
412 		if (g5_fvt_count < 1 || g5_pmode_max < 1)
413 			goto bail_noprops;
414 
415 		g5_switch_volt = g5_smu_switch_volt;
416 		volt_method = "SMU";
417 	} else if (use_volts_vdnap) {
418 		struct device_node *root;
419 
420 		root = of_find_node_by_path("/");
421 		if (root == NULL) {
422 			printk(KERN_ERR "cpufreq: Can't find root of "
423 			       "device tree\n");
424 			goto bail_noprops;
425 		}
426 		pfunc_set_vdnap0 = pmf_find_function(root, "set-vdnap0");
427 		pfunc_vdnap0_complete =
428 			pmf_find_function(root, "slewing-done");
429 		if (pfunc_set_vdnap0 == NULL ||
430 		    pfunc_vdnap0_complete == NULL) {
431 			printk(KERN_ERR "cpufreq: Can't find required "
432 			       "platform function\n");
433 			goto bail_noprops;
434 		}
435 
436 		g5_switch_volt = g5_vdnap_switch_volt;
437 		volt_method = "GPIO";
438 	} else {
439 		g5_switch_volt = g5_dummy_switch_volt;
440 		volt_method = "none";
441 	}
442 
443 	/*
444 	 * From what I see, clock-frequency is always the maximal frequency.
445 	 * The current driver can not slew sysclk yet, so we really only deal
446 	 * with powertune steps for now. We also only implement full freq and
447 	 * half freq in this version. So far, I haven't yet seen a machine
448 	 * supporting anything else.
449 	 */
450 	valp = of_get_property(cpunode, "clock-frequency", NULL);
451 	if (!valp)
452 		return -ENODEV;
453 	max_freq = (*valp)/1000;
454 	g5_cpu_freqs[0].frequency = max_freq;
455 	g5_cpu_freqs[1].frequency = max_freq/2;
456 
457 	/* Set callbacks */
458 	transition_latency = 12000;
459 	g5_switch_freq = g5_scom_switch_freq;
460 	g5_query_freq = g5_scom_query_freq;
461 	freq_method = "SCOM";
462 
463 	/* Force apply current frequency to make sure everything is in
464 	 * sync (voltage is right for example). Firmware may leave us with
465 	 * a strange setting ...
466 	 */
467 	g5_switch_volt(CPUFREQ_HIGH);
468 	msleep(10);
469 	g5_pmode_cur = -1;
470 	g5_switch_freq(g5_query_freq());
471 
472 	printk(KERN_INFO "Registering G5 CPU frequency driver\n");
473 	printk(KERN_INFO "Frequency method: %s, Voltage method: %s\n",
474 	       freq_method, volt_method);
475 	printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
476 		g5_cpu_freqs[1].frequency/1000,
477 		g5_cpu_freqs[0].frequency/1000,
478 		g5_cpu_freqs[g5_pmode_cur].frequency/1000);
479 
480 	rc = cpufreq_register_driver(&g5_cpufreq_driver);
481 
482 	/* We keep the CPU node on hold... hopefully, Apple G5 don't have
483 	 * hotplug CPU with a dynamic device-tree ...
484 	 */
485 	return rc;
486 
487  bail_noprops:
488 	of_node_put(cpunode);
489 
490 	return rc;
491 }
492 
493 #endif /* CONFIG_PMAC_SMU */
494 
495 
496 static int __init g5_pm72_cpufreq_init(struct device_node *cpunode)
497 {
498 	struct device_node *cpuid = NULL, *hwclock = NULL;
499 	const u8 *eeprom = NULL;
500 	const u32 *valp;
501 	u64 max_freq, min_freq, ih, il;
502 	int has_volt = 1, rc = 0;
503 
504 	DBG("cpufreq: Initializing for PowerMac7,2, PowerMac7,3 and"
505 	    " RackMac3,1...\n");
506 
507 	/* Lookup the cpuid eeprom node */
508         cpuid = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/cpuid@a0");
509 	if (cpuid != NULL)
510 		eeprom = of_get_property(cpuid, "cpuid", NULL);
511 	if (eeprom == NULL) {
512 		printk(KERN_ERR "cpufreq: Can't find cpuid EEPROM !\n");
513 		rc = -ENODEV;
514 		goto bail;
515 	}
516 
517 	/* Lookup the i2c hwclock */
518 	for (hwclock = NULL;
519 	     (hwclock = of_find_node_by_name(hwclock, "i2c-hwclock")) != NULL;){
520 		const char *loc = of_get_property(hwclock,
521 				"hwctrl-location", NULL);
522 		if (loc == NULL)
523 			continue;
524 		if (strcmp(loc, "CPU CLOCK"))
525 			continue;
526 		if (!of_get_property(hwclock, "platform-get-frequency", NULL))
527 			continue;
528 		break;
529 	}
530 	if (hwclock == NULL) {
531 		printk(KERN_ERR "cpufreq: Can't find i2c clock chip !\n");
532 		rc = -ENODEV;
533 		goto bail;
534 	}
535 
536 	DBG("cpufreq: i2c clock chip found: %s\n", hwclock->full_name);
537 
538 	/* Now get all the platform functions */
539 	pfunc_cpu_getfreq =
540 		pmf_find_function(hwclock, "get-frequency");
541 	pfunc_cpu_setfreq_high =
542 		pmf_find_function(hwclock, "set-frequency-high");
543 	pfunc_cpu_setfreq_low =
544 		pmf_find_function(hwclock, "set-frequency-low");
545 	pfunc_slewing_done =
546 		pmf_find_function(hwclock, "slewing-done");
547 	pfunc_cpu0_volt_high =
548 		pmf_find_function(hwclock, "set-voltage-high-0");
549 	pfunc_cpu0_volt_low =
550 		pmf_find_function(hwclock, "set-voltage-low-0");
551 	pfunc_cpu1_volt_high =
552 		pmf_find_function(hwclock, "set-voltage-high-1");
553 	pfunc_cpu1_volt_low =
554 		pmf_find_function(hwclock, "set-voltage-low-1");
555 
556 	/* Check we have minimum requirements */
557 	if (pfunc_cpu_getfreq == NULL || pfunc_cpu_setfreq_high == NULL ||
558 	    pfunc_cpu_setfreq_low == NULL || pfunc_slewing_done == NULL) {
559 		printk(KERN_ERR "cpufreq: Can't find platform functions !\n");
560 		rc = -ENODEV;
561 		goto bail;
562 	}
563 
564 	/* Check that we have complete sets */
565 	if (pfunc_cpu0_volt_high == NULL || pfunc_cpu0_volt_low == NULL) {
566 		pmf_put_function(pfunc_cpu0_volt_high);
567 		pmf_put_function(pfunc_cpu0_volt_low);
568 		pfunc_cpu0_volt_high = pfunc_cpu0_volt_low = NULL;
569 		has_volt = 0;
570 	}
571 	if (!has_volt ||
572 	    pfunc_cpu1_volt_high == NULL || pfunc_cpu1_volt_low == NULL) {
573 		pmf_put_function(pfunc_cpu1_volt_high);
574 		pmf_put_function(pfunc_cpu1_volt_low);
575 		pfunc_cpu1_volt_high = pfunc_cpu1_volt_low = NULL;
576 	}
577 
578 	/* Note: The device tree also contains a "platform-set-values"
579 	 * function for which I haven't quite figured out the usage. It
580 	 * might have to be called on init and/or wakeup, I'm not too sure
581 	 * but things seem to work fine without it so far ...
582 	 */
583 
584 	/* Get max frequency from device-tree */
585 	valp = of_get_property(cpunode, "clock-frequency", NULL);
586 	if (!valp) {
587 		printk(KERN_ERR "cpufreq: Can't find CPU frequency !\n");
588 		rc = -ENODEV;
589 		goto bail;
590 	}
591 
592 	max_freq = (*valp)/1000;
593 
594 	/* Now calculate reduced frequency by using the cpuid input freq
595 	 * ratio. This requires 64 bits math unless we are willing to lose
596 	 * some precision
597 	 */
598 	ih = *((u32 *)(eeprom + 0x10));
599 	il = *((u32 *)(eeprom + 0x20));
600 
601 	/* Check for machines with no useful settings */
602 	if (il == ih) {
603 		printk(KERN_WARNING "cpufreq: No low frequency mode available"
604 		       " on this model !\n");
605 		rc = -ENODEV;
606 		goto bail;
607 	}
608 
609 	min_freq = 0;
610 	if (ih != 0 && il != 0)
611 		min_freq = (max_freq * il) / ih;
612 
613 	/* Sanity check */
614 	if (min_freq >= max_freq || min_freq < 1000) {
615 		printk(KERN_ERR "cpufreq: Can't calculate low frequency !\n");
616 		rc = -ENXIO;
617 		goto bail;
618 	}
619 	g5_cpu_freqs[0].frequency = max_freq;
620 	g5_cpu_freqs[1].frequency = min_freq;
621 
622 	/* Based on a measurement on Xserve G5, rounded up. */
623 	transition_latency = 10 * NSEC_PER_MSEC;
624 
625 	/* Set callbacks */
626 	g5_switch_volt = g5_pfunc_switch_volt;
627 	g5_switch_freq = g5_pfunc_switch_freq;
628 	g5_query_freq = g5_pfunc_query_freq;
629 
630 	/* Force apply current frequency to make sure everything is in
631 	 * sync (voltage is right for example). Firmware may leave us with
632 	 * a strange setting ...
633 	 */
634 	g5_switch_volt(CPUFREQ_HIGH);
635 	msleep(10);
636 	g5_pmode_cur = -1;
637 	g5_switch_freq(g5_query_freq());
638 
639 	printk(KERN_INFO "Registering G5 CPU frequency driver\n");
640 	printk(KERN_INFO "Frequency method: i2c/pfunc, "
641 	       "Voltage method: %s\n", has_volt ? "i2c/pfunc" : "none");
642 	printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
643 		g5_cpu_freqs[1].frequency/1000,
644 		g5_cpu_freqs[0].frequency/1000,
645 		g5_cpu_freqs[g5_pmode_cur].frequency/1000);
646 
647 	rc = cpufreq_register_driver(&g5_cpufreq_driver);
648  bail:
649 	if (rc != 0) {
650 		pmf_put_function(pfunc_cpu_getfreq);
651 		pmf_put_function(pfunc_cpu_setfreq_high);
652 		pmf_put_function(pfunc_cpu_setfreq_low);
653 		pmf_put_function(pfunc_slewing_done);
654 		pmf_put_function(pfunc_cpu0_volt_high);
655 		pmf_put_function(pfunc_cpu0_volt_low);
656 		pmf_put_function(pfunc_cpu1_volt_high);
657 		pmf_put_function(pfunc_cpu1_volt_low);
658 	}
659 	of_node_put(hwclock);
660 	of_node_put(cpuid);
661 	of_node_put(cpunode);
662 
663 	return rc;
664 }
665 
666 static int __init g5_cpufreq_init(void)
667 {
668 	struct device_node *cpunode;
669 	int rc = 0;
670 
671 	/* Get first CPU node */
672 	cpunode = of_cpu_device_node_get(0);
673 	if (cpunode == NULL) {
674 		pr_err("cpufreq: Can't find any CPU node\n");
675 		return -ENODEV;
676 	}
677 
678 	if (of_machine_is_compatible("PowerMac7,2") ||
679 	    of_machine_is_compatible("PowerMac7,3") ||
680 	    of_machine_is_compatible("RackMac3,1"))
681 		rc = g5_pm72_cpufreq_init(cpunode);
682 #ifdef CONFIG_PMAC_SMU
683 	else
684 		rc = g5_neo2_cpufreq_init(cpunode);
685 #endif /* CONFIG_PMAC_SMU */
686 
687 	return rc;
688 }
689 
690 module_init(g5_cpufreq_init);
691 
692 
693 MODULE_LICENSE("GPL");
694