xref: /linux/drivers/cpufreq/pmac64-cpufreq.c (revision dd0a11815a339d6deeea8357574f8126a8404c92)
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 static struct freq_attr* g5_cpu_freqs_attr[] = {
74 	&cpufreq_freq_attr_scaling_available_freqs,
75 	NULL,
76 };
77 
78 /* Power mode data is an array of the 32 bits PCR values to use for
79  * the various frequencies, retrieved from the device-tree
80  */
81 static int g5_pmode_cur;
82 
83 static void (*g5_switch_volt)(int speed_mode);
84 static int (*g5_switch_freq)(int speed_mode);
85 static int (*g5_query_freq)(void);
86 
87 static DEFINE_MUTEX(g5_switch_mutex);
88 
89 static unsigned long transition_latency;
90 
91 #ifdef CONFIG_PMAC_SMU
92 
93 static const u32 *g5_pmode_data;
94 static int g5_pmode_max;
95 
96 static struct smu_sdbp_fvt *g5_fvt_table;	/* table of op. points */
97 static int g5_fvt_count;			/* number of op. points */
98 static int g5_fvt_cur;				/* current op. point */
99 
100 /*
101  * SMU based voltage switching for Neo2 platforms
102  */
103 
104 static void g5_smu_switch_volt(int speed_mode)
105 {
106 	struct smu_simple_cmd	cmd;
107 
108 	DECLARE_COMPLETION_ONSTACK(comp);
109 	smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
110 			 &comp, 'V', 'S', 'L', 'E', 'W',
111 			 0xff, g5_fvt_cur+1, speed_mode);
112 	wait_for_completion(&comp);
113 }
114 
115 /*
116  * Platform function based voltage/vdnap switching for Neo2
117  */
118 
119 static struct pmf_function *pfunc_set_vdnap0;
120 static struct pmf_function *pfunc_vdnap0_complete;
121 
122 static void g5_vdnap_switch_volt(int speed_mode)
123 {
124 	struct pmf_args args;
125 	u32 slew, done = 0;
126 	unsigned long timeout;
127 
128 	slew = (speed_mode == CPUFREQ_LOW) ? 1 : 0;
129 	args.count = 1;
130 	args.u[0].p = &slew;
131 
132 	pmf_call_one(pfunc_set_vdnap0, &args);
133 
134 	/* It's an irq GPIO so we should be able to just block here,
135 	 * I'll do that later after I've properly tested the IRQ code for
136 	 * platform functions
137 	 */
138 	timeout = jiffies + HZ/10;
139 	while(!time_after(jiffies, timeout)) {
140 		args.count = 1;
141 		args.u[0].p = &done;
142 		pmf_call_one(pfunc_vdnap0_complete, &args);
143 		if (done)
144 			break;
145 		msleep(1);
146 	}
147 	if (done == 0)
148 		printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
149 }
150 
151 
152 /*
153  * SCOM based frequency switching for 970FX rev3
154  */
155 static int g5_scom_switch_freq(int speed_mode)
156 {
157 	unsigned long flags;
158 	int to;
159 
160 	/* If frequency is going up, first ramp up the voltage */
161 	if (speed_mode < g5_pmode_cur)
162 		g5_switch_volt(speed_mode);
163 
164 	local_irq_save(flags);
165 
166 	/* Clear PCR high */
167 	scom970_write(SCOM_PCR, 0);
168 	/* Clear PCR low */
169        	scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
170 	/* Set PCR low */
171 	scom970_write(SCOM_PCR, PCR_HILO_SELECT |
172 		      g5_pmode_data[speed_mode]);
173 
174 	/* Wait for completion */
175 	for (to = 0; to < 10; to++) {
176 		unsigned long psr = scom970_read(SCOM_PSR);
177 
178 		if ((psr & PSR_CMD_RECEIVED) == 0 &&
179 		    (((psr >> PSR_CUR_SPEED_SHIFT) ^
180 		      (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
181 		    == 0)
182 			break;
183 		if (psr & PSR_CMD_COMPLETED)
184 			break;
185 		udelay(100);
186 	}
187 
188 	local_irq_restore(flags);
189 
190 	/* If frequency is going down, last ramp the voltage */
191 	if (speed_mode > g5_pmode_cur)
192 		g5_switch_volt(speed_mode);
193 
194 	g5_pmode_cur = speed_mode;
195 	ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
196 
197 	return 0;
198 }
199 
200 static int g5_scom_query_freq(void)
201 {
202 	unsigned long psr = scom970_read(SCOM_PSR);
203 	int i;
204 
205 	for (i = 0; i <= g5_pmode_max; i++)
206 		if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
207 		      (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
208 			break;
209 	return i;
210 }
211 
212 /*
213  * Fake voltage switching for platforms with missing support
214  */
215 
216 static void g5_dummy_switch_volt(int speed_mode)
217 {
218 }
219 
220 #endif /* CONFIG_PMAC_SMU */
221 
222 /*
223  * Platform function based voltage switching for PowerMac7,2 & 7,3
224  */
225 
226 static struct pmf_function *pfunc_cpu0_volt_high;
227 static struct pmf_function *pfunc_cpu0_volt_low;
228 static struct pmf_function *pfunc_cpu1_volt_high;
229 static struct pmf_function *pfunc_cpu1_volt_low;
230 
231 static void g5_pfunc_switch_volt(int speed_mode)
232 {
233 	if (speed_mode == CPUFREQ_HIGH) {
234 		if (pfunc_cpu0_volt_high)
235 			pmf_call_one(pfunc_cpu0_volt_high, NULL);
236 		if (pfunc_cpu1_volt_high)
237 			pmf_call_one(pfunc_cpu1_volt_high, NULL);
238 	} else {
239 		if (pfunc_cpu0_volt_low)
240 			pmf_call_one(pfunc_cpu0_volt_low, NULL);
241 		if (pfunc_cpu1_volt_low)
242 			pmf_call_one(pfunc_cpu1_volt_low, NULL);
243 	}
244 	msleep(10); /* should be faster , to fix */
245 }
246 
247 /*
248  * Platform function based frequency switching for PowerMac7,2 & 7,3
249  */
250 
251 static struct pmf_function *pfunc_cpu_setfreq_high;
252 static struct pmf_function *pfunc_cpu_setfreq_low;
253 static struct pmf_function *pfunc_cpu_getfreq;
254 static struct pmf_function *pfunc_slewing_done;
255 
256 static int g5_pfunc_switch_freq(int speed_mode)
257 {
258 	struct pmf_args args;
259 	u32 done = 0;
260 	unsigned long timeout;
261 	int rc;
262 
263 	DBG("g5_pfunc_switch_freq(%d)\n", speed_mode);
264 
265 	/* If frequency is going up, first ramp up the voltage */
266 	if (speed_mode < g5_pmode_cur)
267 		g5_switch_volt(speed_mode);
268 
269 	/* Do it */
270 	if (speed_mode == CPUFREQ_HIGH)
271 		rc = pmf_call_one(pfunc_cpu_setfreq_high, NULL);
272 	else
273 		rc = pmf_call_one(pfunc_cpu_setfreq_low, NULL);
274 
275 	if (rc)
276 		printk(KERN_WARNING "cpufreq: pfunc switch error %d\n", rc);
277 
278 	/* It's an irq GPIO so we should be able to just block here,
279 	 * I'll do that later after I've properly tested the IRQ code for
280 	 * platform functions
281 	 */
282 	timeout = jiffies + HZ/10;
283 	while(!time_after(jiffies, timeout)) {
284 		args.count = 1;
285 		args.u[0].p = &done;
286 		pmf_call_one(pfunc_slewing_done, &args);
287 		if (done)
288 			break;
289 		msleep(1);
290 	}
291 	if (done == 0)
292 		printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
293 
294 	/* If frequency is going down, last ramp the voltage */
295 	if (speed_mode > g5_pmode_cur)
296 		g5_switch_volt(speed_mode);
297 
298 	g5_pmode_cur = speed_mode;
299 	ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
300 
301 	return 0;
302 }
303 
304 static int g5_pfunc_query_freq(void)
305 {
306 	struct pmf_args args;
307 	u32 val = 0;
308 
309 	args.count = 1;
310 	args.u[0].p = &val;
311 	pmf_call_one(pfunc_cpu_getfreq, &args);
312 	return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
313 }
314 
315 
316 /*
317  * Common interface to the cpufreq core
318  */
319 
320 static int g5_cpufreq_verify(struct cpufreq_policy *policy)
321 {
322 	return cpufreq_frequency_table_verify(policy, g5_cpu_freqs);
323 }
324 
325 static int g5_cpufreq_target(struct cpufreq_policy *policy,
326 	unsigned int target_freq, unsigned int relation)
327 {
328 	unsigned int newstate = 0;
329 	struct cpufreq_freqs freqs;
330 	int rc;
331 
332 	if (cpufreq_frequency_table_target(policy, g5_cpu_freqs,
333 			target_freq, relation, &newstate))
334 		return -EINVAL;
335 
336 	if (g5_pmode_cur == newstate)
337 		return 0;
338 
339 	mutex_lock(&g5_switch_mutex);
340 
341 	freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
342 	freqs.new = g5_cpu_freqs[newstate].frequency;
343 
344 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
345 	rc = g5_switch_freq(newstate);
346 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
347 
348 	mutex_unlock(&g5_switch_mutex);
349 
350 	return rc;
351 }
352 
353 static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
354 {
355 	return g5_cpu_freqs[g5_pmode_cur].frequency;
356 }
357 
358 static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
359 {
360 	policy->cpuinfo.transition_latency = transition_latency;
361 	policy->cur = g5_cpu_freqs[g5_query_freq()].frequency;
362 	/* secondary CPUs are tied to the primary one by the
363 	 * cpufreq core if in the secondary policy we tell it that
364 	 * it actually must be one policy together with all others. */
365 	cpumask_copy(policy->cpus, cpu_online_mask);
366 	cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu);
367 
368 	return cpufreq_frequency_table_cpuinfo(policy,
369 		g5_cpu_freqs);
370 }
371 
372 
373 static struct cpufreq_driver g5_cpufreq_driver = {
374 	.name		= "powermac",
375 	.flags		= CPUFREQ_CONST_LOOPS,
376 	.init		= g5_cpufreq_cpu_init,
377 	.verify		= g5_cpufreq_verify,
378 	.target		= g5_cpufreq_target,
379 	.get		= g5_cpufreq_get_speed,
380 	.attr 		= g5_cpu_freqs_attr,
381 };
382 
383 
384 #ifdef CONFIG_PMAC_SMU
385 
386 static int __init g5_neo2_cpufreq_init(struct device_node *cpunode)
387 {
388 	unsigned int psize, ssize;
389 	unsigned long max_freq;
390 	char *freq_method, *volt_method;
391 	const u32 *valp;
392 	u32 pvr_hi;
393 	int use_volts_vdnap = 0;
394 	int use_volts_smu = 0;
395 	int rc = -ENODEV;
396 
397 	/* Check supported platforms */
398 	if (of_machine_is_compatible("PowerMac8,1") ||
399 	    of_machine_is_compatible("PowerMac8,2") ||
400 	    of_machine_is_compatible("PowerMac9,1"))
401 		use_volts_smu = 1;
402 	else if (of_machine_is_compatible("PowerMac11,2"))
403 		use_volts_vdnap = 1;
404 	else
405 		return -ENODEV;
406 
407 	/* Check 970FX for now */
408 	valp = of_get_property(cpunode, "cpu-version", NULL);
409 	if (!valp) {
410 		DBG("No cpu-version property !\n");
411 		goto bail_noprops;
412 	}
413 	pvr_hi = (*valp) >> 16;
414 	if (pvr_hi != 0x3c && pvr_hi != 0x44) {
415 		printk(KERN_ERR "cpufreq: Unsupported CPU version\n");
416 		goto bail_noprops;
417 	}
418 
419 	/* Look for the powertune data in the device-tree */
420 	g5_pmode_data = of_get_property(cpunode, "power-mode-data",&psize);
421 	if (!g5_pmode_data) {
422 		DBG("No power-mode-data !\n");
423 		goto bail_noprops;
424 	}
425 	g5_pmode_max = psize / sizeof(u32) - 1;
426 
427 	if (use_volts_smu) {
428 		const struct smu_sdbp_header *shdr;
429 
430 		/* Look for the FVT table */
431 		shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
432 		if (!shdr)
433 			goto bail_noprops;
434 		g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
435 		ssize = (shdr->len * sizeof(u32)) - sizeof(*shdr);
436 		g5_fvt_count = ssize / sizeof(*g5_fvt_table);
437 		g5_fvt_cur = 0;
438 
439 		/* Sanity checking */
440 		if (g5_fvt_count < 1 || g5_pmode_max < 1)
441 			goto bail_noprops;
442 
443 		g5_switch_volt = g5_smu_switch_volt;
444 		volt_method = "SMU";
445 	} else if (use_volts_vdnap) {
446 		struct device_node *root;
447 
448 		root = of_find_node_by_path("/");
449 		if (root == NULL) {
450 			printk(KERN_ERR "cpufreq: Can't find root of "
451 			       "device tree\n");
452 			goto bail_noprops;
453 		}
454 		pfunc_set_vdnap0 = pmf_find_function(root, "set-vdnap0");
455 		pfunc_vdnap0_complete =
456 			pmf_find_function(root, "slewing-done");
457 		if (pfunc_set_vdnap0 == NULL ||
458 		    pfunc_vdnap0_complete == NULL) {
459 			printk(KERN_ERR "cpufreq: Can't find required "
460 			       "platform function\n");
461 			goto bail_noprops;
462 		}
463 
464 		g5_switch_volt = g5_vdnap_switch_volt;
465 		volt_method = "GPIO";
466 	} else {
467 		g5_switch_volt = g5_dummy_switch_volt;
468 		volt_method = "none";
469 	}
470 
471 	/*
472 	 * From what I see, clock-frequency is always the maximal frequency.
473 	 * The current driver can not slew sysclk yet, so we really only deal
474 	 * with powertune steps for now. We also only implement full freq and
475 	 * half freq in this version. So far, I haven't yet seen a machine
476 	 * supporting anything else.
477 	 */
478 	valp = of_get_property(cpunode, "clock-frequency", NULL);
479 	if (!valp)
480 		return -ENODEV;
481 	max_freq = (*valp)/1000;
482 	g5_cpu_freqs[0].frequency = max_freq;
483 	g5_cpu_freqs[1].frequency = max_freq/2;
484 
485 	/* Set callbacks */
486 	transition_latency = 12000;
487 	g5_switch_freq = g5_scom_switch_freq;
488 	g5_query_freq = g5_scom_query_freq;
489 	freq_method = "SCOM";
490 
491 	/* Force apply current frequency to make sure everything is in
492 	 * sync (voltage is right for example). Firmware may leave us with
493 	 * a strange setting ...
494 	 */
495 	g5_switch_volt(CPUFREQ_HIGH);
496 	msleep(10);
497 	g5_pmode_cur = -1;
498 	g5_switch_freq(g5_query_freq());
499 
500 	printk(KERN_INFO "Registering G5 CPU frequency driver\n");
501 	printk(KERN_INFO "Frequency method: %s, Voltage method: %s\n",
502 	       freq_method, volt_method);
503 	printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
504 		g5_cpu_freqs[1].frequency/1000,
505 		g5_cpu_freqs[0].frequency/1000,
506 		g5_cpu_freqs[g5_pmode_cur].frequency/1000);
507 
508 	rc = cpufreq_register_driver(&g5_cpufreq_driver);
509 
510 	/* We keep the CPU node on hold... hopefully, Apple G5 don't have
511 	 * hotplug CPU with a dynamic device-tree ...
512 	 */
513 	return rc;
514 
515  bail_noprops:
516 	of_node_put(cpunode);
517 
518 	return rc;
519 }
520 
521 #endif /* CONFIG_PMAC_SMU */
522 
523 
524 static int __init g5_pm72_cpufreq_init(struct device_node *cpunode)
525 {
526 	struct device_node *cpuid = NULL, *hwclock = NULL;
527 	const u8 *eeprom = NULL;
528 	const u32 *valp;
529 	u64 max_freq, min_freq, ih, il;
530 	int has_volt = 1, rc = 0;
531 
532 	DBG("cpufreq: Initializing for PowerMac7,2, PowerMac7,3 and"
533 	    " RackMac3,1...\n");
534 
535 	/* Lookup the cpuid eeprom node */
536         cpuid = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/cpuid@a0");
537 	if (cpuid != NULL)
538 		eeprom = of_get_property(cpuid, "cpuid", NULL);
539 	if (eeprom == NULL) {
540 		printk(KERN_ERR "cpufreq: Can't find cpuid EEPROM !\n");
541 		rc = -ENODEV;
542 		goto bail;
543 	}
544 
545 	/* Lookup the i2c hwclock */
546 	for (hwclock = NULL;
547 	     (hwclock = of_find_node_by_name(hwclock, "i2c-hwclock")) != NULL;){
548 		const char *loc = of_get_property(hwclock,
549 				"hwctrl-location", NULL);
550 		if (loc == NULL)
551 			continue;
552 		if (strcmp(loc, "CPU CLOCK"))
553 			continue;
554 		if (!of_get_property(hwclock, "platform-get-frequency", NULL))
555 			continue;
556 		break;
557 	}
558 	if (hwclock == NULL) {
559 		printk(KERN_ERR "cpufreq: Can't find i2c clock chip !\n");
560 		rc = -ENODEV;
561 		goto bail;
562 	}
563 
564 	DBG("cpufreq: i2c clock chip found: %s\n", hwclock->full_name);
565 
566 	/* Now get all the platform functions */
567 	pfunc_cpu_getfreq =
568 		pmf_find_function(hwclock, "get-frequency");
569 	pfunc_cpu_setfreq_high =
570 		pmf_find_function(hwclock, "set-frequency-high");
571 	pfunc_cpu_setfreq_low =
572 		pmf_find_function(hwclock, "set-frequency-low");
573 	pfunc_slewing_done =
574 		pmf_find_function(hwclock, "slewing-done");
575 	pfunc_cpu0_volt_high =
576 		pmf_find_function(hwclock, "set-voltage-high-0");
577 	pfunc_cpu0_volt_low =
578 		pmf_find_function(hwclock, "set-voltage-low-0");
579 	pfunc_cpu1_volt_high =
580 		pmf_find_function(hwclock, "set-voltage-high-1");
581 	pfunc_cpu1_volt_low =
582 		pmf_find_function(hwclock, "set-voltage-low-1");
583 
584 	/* Check we have minimum requirements */
585 	if (pfunc_cpu_getfreq == NULL || pfunc_cpu_setfreq_high == NULL ||
586 	    pfunc_cpu_setfreq_low == NULL || pfunc_slewing_done == NULL) {
587 		printk(KERN_ERR "cpufreq: Can't find platform functions !\n");
588 		rc = -ENODEV;
589 		goto bail;
590 	}
591 
592 	/* Check that we have complete sets */
593 	if (pfunc_cpu0_volt_high == NULL || pfunc_cpu0_volt_low == NULL) {
594 		pmf_put_function(pfunc_cpu0_volt_high);
595 		pmf_put_function(pfunc_cpu0_volt_low);
596 		pfunc_cpu0_volt_high = pfunc_cpu0_volt_low = NULL;
597 		has_volt = 0;
598 	}
599 	if (!has_volt ||
600 	    pfunc_cpu1_volt_high == NULL || pfunc_cpu1_volt_low == NULL) {
601 		pmf_put_function(pfunc_cpu1_volt_high);
602 		pmf_put_function(pfunc_cpu1_volt_low);
603 		pfunc_cpu1_volt_high = pfunc_cpu1_volt_low = NULL;
604 	}
605 
606 	/* Note: The device tree also contains a "platform-set-values"
607 	 * function for which I haven't quite figured out the usage. It
608 	 * might have to be called on init and/or wakeup, I'm not too sure
609 	 * but things seem to work fine without it so far ...
610 	 */
611 
612 	/* Get max frequency from device-tree */
613 	valp = of_get_property(cpunode, "clock-frequency", NULL);
614 	if (!valp) {
615 		printk(KERN_ERR "cpufreq: Can't find CPU frequency !\n");
616 		rc = -ENODEV;
617 		goto bail;
618 	}
619 
620 	max_freq = (*valp)/1000;
621 
622 	/* Now calculate reduced frequency by using the cpuid input freq
623 	 * ratio. This requires 64 bits math unless we are willing to lose
624 	 * some precision
625 	 */
626 	ih = *((u32 *)(eeprom + 0x10));
627 	il = *((u32 *)(eeprom + 0x20));
628 
629 	/* Check for machines with no useful settings */
630 	if (il == ih) {
631 		printk(KERN_WARNING "cpufreq: No low frequency mode available"
632 		       " on this model !\n");
633 		rc = -ENODEV;
634 		goto bail;
635 	}
636 
637 	min_freq = 0;
638 	if (ih != 0 && il != 0)
639 		min_freq = (max_freq * il) / ih;
640 
641 	/* Sanity check */
642 	if (min_freq >= max_freq || min_freq < 1000) {
643 		printk(KERN_ERR "cpufreq: Can't calculate low frequency !\n");
644 		rc = -ENXIO;
645 		goto bail;
646 	}
647 	g5_cpu_freqs[0].frequency = max_freq;
648 	g5_cpu_freqs[1].frequency = min_freq;
649 
650 	/* Set callbacks */
651 	transition_latency = CPUFREQ_ETERNAL;
652 	g5_switch_volt = g5_pfunc_switch_volt;
653 	g5_switch_freq = g5_pfunc_switch_freq;
654 	g5_query_freq = g5_pfunc_query_freq;
655 
656 	/* Force apply current frequency to make sure everything is in
657 	 * sync (voltage is right for example). Firmware may leave us with
658 	 * a strange setting ...
659 	 */
660 	g5_switch_volt(CPUFREQ_HIGH);
661 	msleep(10);
662 	g5_pmode_cur = -1;
663 	g5_switch_freq(g5_query_freq());
664 
665 	printk(KERN_INFO "Registering G5 CPU frequency driver\n");
666 	printk(KERN_INFO "Frequency method: i2c/pfunc, "
667 	       "Voltage method: %s\n", has_volt ? "i2c/pfunc" : "none");
668 	printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
669 		g5_cpu_freqs[1].frequency/1000,
670 		g5_cpu_freqs[0].frequency/1000,
671 		g5_cpu_freqs[g5_pmode_cur].frequency/1000);
672 
673 	rc = cpufreq_register_driver(&g5_cpufreq_driver);
674  bail:
675 	if (rc != 0) {
676 		pmf_put_function(pfunc_cpu_getfreq);
677 		pmf_put_function(pfunc_cpu_setfreq_high);
678 		pmf_put_function(pfunc_cpu_setfreq_low);
679 		pmf_put_function(pfunc_slewing_done);
680 		pmf_put_function(pfunc_cpu0_volt_high);
681 		pmf_put_function(pfunc_cpu0_volt_low);
682 		pmf_put_function(pfunc_cpu1_volt_high);
683 		pmf_put_function(pfunc_cpu1_volt_low);
684 	}
685 	of_node_put(hwclock);
686 	of_node_put(cpuid);
687 	of_node_put(cpunode);
688 
689 	return rc;
690 }
691 
692 static int __init g5_cpufreq_init(void)
693 {
694 	struct device_node *cpunode;
695 	int rc = 0;
696 
697 	/* Get first CPU node */
698 	cpunode = of_cpu_device_node_get(0);
699 	if (cpunode == NULL) {
700 		pr_err("cpufreq: Can't find any CPU node\n");
701 		return -ENODEV;
702 	}
703 
704 	if (of_machine_is_compatible("PowerMac7,2") ||
705 	    of_machine_is_compatible("PowerMac7,3") ||
706 	    of_machine_is_compatible("RackMac3,1"))
707 		rc = g5_pm72_cpufreq_init(cpunode);
708 #ifdef CONFIG_PMAC_SMU
709 	else
710 		rc = g5_neo2_cpufreq_init(cpunode);
711 #endif /* CONFIG_PMAC_SMU */
712 
713 	return rc;
714 }
715 
716 module_init(g5_cpufreq_init);
717 
718 
719 MODULE_LICENSE("GPL");
720