xref: /linux/drivers/cpufreq/pmac32-cpufreq.c (revision 561add0da6d3d07c9bccb0832fb6ed5619167d26)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
4  *  Copyright (C) 2004        John Steele Scott <toojays@toojays.net>
5  *
6  * TODO: Need a big cleanup here. Basically, we need to have different
7  * cpufreq_driver structures for the different type of HW instead of the
8  * current mess. We also need to better deal with the detection of the
9  * type of machine.
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/errno.h>
17 #include <linux/kernel.h>
18 #include <linux/delay.h>
19 #include <linux/sched.h>
20 #include <linux/adb.h>
21 #include <linux/pmu.h>
22 #include <linux/cpufreq.h>
23 #include <linux/init.h>
24 #include <linux/device.h>
25 #include <linux/hardirq.h>
26 #include <linux/of.h>
27 
28 #include <asm/machdep.h>
29 #include <asm/irq.h>
30 #include <asm/pmac_feature.h>
31 #include <asm/mmu_context.h>
32 #include <asm/sections.h>
33 #include <asm/cputable.h>
34 #include <asm/time.h>
35 #include <asm/mpic.h>
36 #include <asm/keylargo.h>
37 #include <asm/switch_to.h>
38 
39 /* WARNING !!! This will cause calibrate_delay() to be called,
40  * but this is an __init function ! So you MUST go edit
41  * init/main.c to make it non-init before enabling DEBUG_FREQ
42  */
43 #undef DEBUG_FREQ
44 
45 extern void low_choose_7447a_dfs(int dfs);
46 extern void low_choose_750fx_pll(int pll);
47 extern void low_sleep_handler(void);
48 
49 /*
50  * Currently, PowerMac cpufreq supports only high & low frequencies
51  * that are set by the firmware
52  */
53 static unsigned int low_freq;
54 static unsigned int hi_freq;
55 static unsigned int cur_freq;
56 static unsigned int sleep_freq;
57 static unsigned long transition_latency;
58 
59 /*
60  * Different models uses different mechanisms to switch the frequency
61  */
62 static int (*set_speed_proc)(int low_speed);
63 static unsigned int (*get_speed_proc)(void);
64 
65 /*
66  * Some definitions used by the various speedprocs
67  */
68 static u32 voltage_gpio;
69 static u32 frequency_gpio;
70 static u32 slew_done_gpio;
71 static int no_schedule;
72 static int has_cpu_l2lve;
73 static int is_pmu_based;
74 
75 /* There are only two frequency states for each processor. Values
76  * are in kHz for the time being.
77  */
78 #define CPUFREQ_HIGH                  0
79 #define CPUFREQ_LOW                   1
80 
81 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
82 	{0, CPUFREQ_HIGH,	0},
83 	{0, CPUFREQ_LOW,	0},
84 	{0, 0,			CPUFREQ_TABLE_END},
85 };
86 
87 static inline void local_delay(unsigned long ms)
88 {
89 	if (no_schedule)
90 		mdelay(ms);
91 	else
92 		msleep(ms);
93 }
94 
95 #ifdef DEBUG_FREQ
96 static inline void debug_calc_bogomips(void)
97 {
98 	/* This will cause a recalc of bogomips and display the
99 	 * result. We backup/restore the value to avoid affecting the
100 	 * core cpufreq framework's own calculation.
101 	 */
102 	unsigned long save_lpj = loops_per_jiffy;
103 	calibrate_delay();
104 	loops_per_jiffy = save_lpj;
105 }
106 #endif /* DEBUG_FREQ */
107 
108 /* Switch CPU speed under 750FX CPU control
109  */
110 static int cpu_750fx_cpu_speed(int low_speed)
111 {
112 	u32 hid2;
113 
114 	if (low_speed == 0) {
115 		/* ramping up, set voltage first */
116 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
117 		/* Make sure we sleep for at least 1ms */
118 		local_delay(10);
119 
120 		/* tweak L2 for high voltage */
121 		if (has_cpu_l2lve) {
122 			hid2 = mfspr(SPRN_HID2);
123 			hid2 &= ~0x2000;
124 			mtspr(SPRN_HID2, hid2);
125 		}
126 	}
127 #ifdef CONFIG_PPC_BOOK3S_32
128 	low_choose_750fx_pll(low_speed);
129 #endif
130 	if (low_speed == 1) {
131 		/* tweak L2 for low voltage */
132 		if (has_cpu_l2lve) {
133 			hid2 = mfspr(SPRN_HID2);
134 			hid2 |= 0x2000;
135 			mtspr(SPRN_HID2, hid2);
136 		}
137 
138 		/* ramping down, set voltage last */
139 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
140 		local_delay(10);
141 	}
142 
143 	return 0;
144 }
145 
146 static unsigned int cpu_750fx_get_cpu_speed(void)
147 {
148 	if (mfspr(SPRN_HID1) & HID1_PS)
149 		return low_freq;
150 	else
151 		return hi_freq;
152 }
153 
154 /* Switch CPU speed using DFS */
155 static int dfs_set_cpu_speed(int low_speed)
156 {
157 	if (low_speed == 0) {
158 		/* ramping up, set voltage first */
159 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
160 		/* Make sure we sleep for at least 1ms */
161 		local_delay(1);
162 	}
163 
164 	/* set frequency */
165 #ifdef CONFIG_PPC_BOOK3S_32
166 	low_choose_7447a_dfs(low_speed);
167 #endif
168 	udelay(100);
169 
170 	if (low_speed == 1) {
171 		/* ramping down, set voltage last */
172 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
173 		local_delay(1);
174 	}
175 
176 	return 0;
177 }
178 
179 static unsigned int dfs_get_cpu_speed(void)
180 {
181 	if (mfspr(SPRN_HID1) & HID1_DFS)
182 		return low_freq;
183 	else
184 		return hi_freq;
185 }
186 
187 
188 /* Switch CPU speed using slewing GPIOs
189  */
190 static int gpios_set_cpu_speed(int low_speed)
191 {
192 	int gpio, timeout = 0;
193 
194 	/* If ramping up, set voltage first */
195 	if (low_speed == 0) {
196 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
197 		/* Delay is way too big but it's ok, we schedule */
198 		local_delay(10);
199 	}
200 
201 	/* Set frequency */
202 	gpio = 	pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
203 	if (low_speed == ((gpio & 0x01) == 0))
204 		goto skip;
205 
206 	pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
207 			  low_speed ? 0x04 : 0x05);
208 	udelay(200);
209 	do {
210 		if (++timeout > 100)
211 			break;
212 		local_delay(1);
213 		gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
214 	} while((gpio & 0x02) == 0);
215  skip:
216 	/* If ramping down, set voltage last */
217 	if (low_speed == 1) {
218 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
219 		/* Delay is way too big but it's ok, we schedule */
220 		local_delay(10);
221 	}
222 
223 #ifdef DEBUG_FREQ
224 	debug_calc_bogomips();
225 #endif
226 
227 	return 0;
228 }
229 
230 /* Switch CPU speed under PMU control
231  */
232 static int pmu_set_cpu_speed(int low_speed)
233 {
234 	struct adb_request req;
235 	unsigned long save_l2cr;
236 	unsigned long save_l3cr;
237 	unsigned int pic_prio;
238 	unsigned long flags;
239 
240 	preempt_disable();
241 
242 #ifdef DEBUG_FREQ
243 	printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
244 #endif
245 	pmu_suspend();
246 
247 	/* Disable all interrupt sources on openpic */
248  	pic_prio = mpic_cpu_get_priority();
249 	mpic_cpu_set_priority(0xf);
250 
251 	/* Make sure the decrementer won't interrupt us */
252 	asm volatile("mtdec %0" : : "r" (0x7fffffff));
253 	/* Make sure any pending DEC interrupt occurring while we did
254 	 * the above didn't re-enable the DEC */
255 	mb();
256 	asm volatile("mtdec %0" : : "r" (0x7fffffff));
257 
258 	/* We can now disable MSR_EE */
259 	local_irq_save(flags);
260 
261 	/* Giveup the FPU & vec */
262 	enable_kernel_fp();
263 
264 #ifdef CONFIG_ALTIVEC
265 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
266 		enable_kernel_altivec();
267 #endif /* CONFIG_ALTIVEC */
268 
269 	/* Save & disable L2 and L3 caches */
270 	save_l3cr = _get_L3CR();	/* (returns -1 if not available) */
271 	save_l2cr = _get_L2CR();	/* (returns -1 if not available) */
272 
273 	/* Send the new speed command. My assumption is that this command
274 	 * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
275 	 */
276 	pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
277 	while (!req.complete)
278 		pmu_poll();
279 
280 	/* Prepare the northbridge for the speed transition */
281 	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
282 
283 	/* Call low level code to backup CPU state and recover from
284 	 * hardware reset
285 	 */
286 	low_sleep_handler();
287 
288 	/* Restore the northbridge */
289 	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
290 
291 	/* Restore L2 cache */
292 	if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
293  		_set_L2CR(save_l2cr);
294 	/* Restore L3 cache */
295 	if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
296  		_set_L3CR(save_l3cr);
297 
298 	/* Restore userland MMU context */
299 	switch_mmu_context(NULL, current->active_mm, NULL);
300 
301 #ifdef DEBUG_FREQ
302 	printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
303 #endif
304 
305 	/* Restore low level PMU operations */
306 	pmu_unlock();
307 
308 	/*
309 	 * Restore decrementer; we'll take a decrementer interrupt
310 	 * as soon as interrupts are re-enabled and the generic
311 	 * clockevents code will reprogram it with the right value.
312 	 */
313 	set_dec(1);
314 
315 	/* Restore interrupts */
316  	mpic_cpu_set_priority(pic_prio);
317 
318 	/* Let interrupts flow again ... */
319 	local_irq_restore(flags);
320 
321 #ifdef DEBUG_FREQ
322 	debug_calc_bogomips();
323 #endif
324 
325 	pmu_resume();
326 
327 	preempt_enable();
328 
329 	return 0;
330 }
331 
332 static int do_set_cpu_speed(struct cpufreq_policy *policy, int speed_mode)
333 {
334 	unsigned long l3cr;
335 	static unsigned long prev_l3cr;
336 
337 	if (speed_mode == CPUFREQ_LOW &&
338 	    cpu_has_feature(CPU_FTR_L3CR)) {
339 		l3cr = _get_L3CR();
340 		if (l3cr & L3CR_L3E) {
341 			prev_l3cr = l3cr;
342 			_set_L3CR(0);
343 		}
344 	}
345 	set_speed_proc(speed_mode == CPUFREQ_LOW);
346 	if (speed_mode == CPUFREQ_HIGH &&
347 	    cpu_has_feature(CPU_FTR_L3CR)) {
348 		l3cr = _get_L3CR();
349 		if ((prev_l3cr & L3CR_L3E) && l3cr != prev_l3cr)
350 			_set_L3CR(prev_l3cr);
351 	}
352 	cur_freq = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
353 
354 	return 0;
355 }
356 
357 static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
358 {
359 	return cur_freq;
360 }
361 
362 static int pmac_cpufreq_target(	struct cpufreq_policy *policy,
363 					unsigned int index)
364 {
365 	int		rc;
366 
367 	rc = do_set_cpu_speed(policy, index);
368 
369 	ppc_proc_freq = cur_freq * 1000ul;
370 	return rc;
371 }
372 
373 static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
374 {
375 	cpufreq_generic_init(policy, pmac_cpu_freqs, transition_latency);
376 	return 0;
377 }
378 
379 static u32 read_gpio(struct device_node *np)
380 {
381 	const u32 *reg = of_get_property(np, "reg", NULL);
382 	u32 offset;
383 
384 	if (reg == NULL)
385 		return 0;
386 	/* That works for all keylargos but shall be fixed properly
387 	 * some day... The problem is that it seems we can't rely
388 	 * on the "reg" property of the GPIO nodes, they are either
389 	 * relative to the base of KeyLargo or to the base of the
390 	 * GPIO space, and the device-tree doesn't help.
391 	 */
392 	offset = *reg;
393 	if (offset < KEYLARGO_GPIO_LEVELS0)
394 		offset += KEYLARGO_GPIO_LEVELS0;
395 	return offset;
396 }
397 
398 static int pmac_cpufreq_suspend(struct cpufreq_policy *policy)
399 {
400 	/* Ok, this could be made a bit smarter, but let's be robust for now. We
401 	 * always force a speed change to high speed before sleep, to make sure
402 	 * we have appropriate voltage and/or bus speed for the wakeup process,
403 	 * and to make sure our loops_per_jiffies are "good enough", that is will
404 	 * not cause too short delays if we sleep in low speed and wake in high
405 	 * speed..
406 	 */
407 	no_schedule = 1;
408 	sleep_freq = cur_freq;
409 	if (cur_freq == low_freq && !is_pmu_based)
410 		do_set_cpu_speed(policy, CPUFREQ_HIGH);
411 	return 0;
412 }
413 
414 static int pmac_cpufreq_resume(struct cpufreq_policy *policy)
415 {
416 	/* If we resume, first check if we have a get() function */
417 	if (get_speed_proc)
418 		cur_freq = get_speed_proc();
419 	else
420 		cur_freq = 0;
421 
422 	/* We don't, hrm... we don't really know our speed here, best
423 	 * is that we force a switch to whatever it was, which is
424 	 * probably high speed due to our suspend() routine
425 	 */
426 	do_set_cpu_speed(policy, sleep_freq == low_freq ?
427 			 CPUFREQ_LOW : CPUFREQ_HIGH);
428 
429 	ppc_proc_freq = cur_freq * 1000ul;
430 
431 	no_schedule = 0;
432 	return 0;
433 }
434 
435 static struct cpufreq_driver pmac_cpufreq_driver = {
436 	.verify 	= cpufreq_generic_frequency_table_verify,
437 	.target_index	= pmac_cpufreq_target,
438 	.get		= pmac_cpufreq_get_speed,
439 	.init		= pmac_cpufreq_cpu_init,
440 	.suspend	= pmac_cpufreq_suspend,
441 	.resume		= pmac_cpufreq_resume,
442 	.flags		= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
443 	.attr		= cpufreq_generic_attr,
444 	.name		= "powermac",
445 };
446 
447 
448 static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
449 {
450 	struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
451 								"voltage-gpio");
452 	struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
453 								"frequency-gpio");
454 	struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
455 								     "slewing-done");
456 	const u32 *value;
457 
458 	/*
459 	 * Check to see if it's GPIO driven or PMU only
460 	 *
461 	 * The way we extract the GPIO address is slightly hackish, but it
462 	 * works well enough for now. We need to abstract the whole GPIO
463 	 * stuff sooner or later anyway
464 	 */
465 
466 	if (volt_gpio_np)
467 		voltage_gpio = read_gpio(volt_gpio_np);
468 	if (freq_gpio_np)
469 		frequency_gpio = read_gpio(freq_gpio_np);
470 	if (slew_done_gpio_np)
471 		slew_done_gpio = read_gpio(slew_done_gpio_np);
472 
473 	of_node_put(volt_gpio_np);
474 	of_node_put(freq_gpio_np);
475 	of_node_put(slew_done_gpio_np);
476 
477 	/* If we use the frequency GPIOs, calculate the min/max speeds based
478 	 * on the bus frequencies
479 	 */
480 	if (frequency_gpio && slew_done_gpio) {
481 		int lenp, rc;
482 		const u32 *freqs, *ratio;
483 
484 		freqs = of_get_property(cpunode, "bus-frequencies", &lenp);
485 		lenp /= sizeof(u32);
486 		if (freqs == NULL || lenp != 2) {
487 			pr_err("bus-frequencies incorrect or missing\n");
488 			return 1;
489 		}
490 		ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",
491 						NULL);
492 		if (ratio == NULL) {
493 			pr_err("processor-to-bus-ratio*2 missing\n");
494 			return 1;
495 		}
496 
497 		/* Get the min/max bus frequencies */
498 		low_freq = min(freqs[0], freqs[1]);
499 		hi_freq = max(freqs[0], freqs[1]);
500 
501 		/* Grrrr.. It _seems_ that the device-tree is lying on the low bus
502 		 * frequency, it claims it to be around 84Mhz on some models while
503 		 * it appears to be approx. 101Mhz on all. Let's hack around here...
504 		 * fortunately, we don't need to be too precise
505 		 */
506 		if (low_freq < 98000000)
507 			low_freq = 101000000;
508 
509 		/* Convert those to CPU core clocks */
510 		low_freq = (low_freq * (*ratio)) / 2000;
511 		hi_freq = (hi_freq * (*ratio)) / 2000;
512 
513 		/* Now we get the frequencies, we read the GPIO to see what is out current
514 		 * speed
515 		 */
516 		rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
517 		cur_freq = (rc & 0x01) ? hi_freq : low_freq;
518 
519 		set_speed_proc = gpios_set_cpu_speed;
520 		return 1;
521 	}
522 
523 	/* If we use the PMU, look for the min & max frequencies in the
524 	 * device-tree
525 	 */
526 	value = of_get_property(cpunode, "min-clock-frequency", NULL);
527 	if (!value)
528 		return 1;
529 	low_freq = (*value) / 1000;
530 	/* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
531 	 * here */
532 	if (low_freq < 100000)
533 		low_freq *= 10;
534 
535 	value = of_get_property(cpunode, "max-clock-frequency", NULL);
536 	if (!value)
537 		return 1;
538 	hi_freq = (*value) / 1000;
539 	set_speed_proc = pmu_set_cpu_speed;
540 	is_pmu_based = 1;
541 
542 	return 0;
543 }
544 
545 static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
546 {
547 	struct device_node *volt_gpio_np;
548 
549 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))
550 		return 1;
551 
552 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
553 	if (volt_gpio_np)
554 		voltage_gpio = read_gpio(volt_gpio_np);
555 	of_node_put(volt_gpio_np);
556 	if (!voltage_gpio){
557 		pr_err("missing cpu-vcore-select gpio\n");
558 		return 1;
559 	}
560 
561 	/* OF only reports the high frequency */
562 	hi_freq = cur_freq;
563 	low_freq = cur_freq/2;
564 
565 	/* Read actual frequency from CPU */
566 	cur_freq = dfs_get_cpu_speed();
567 	set_speed_proc = dfs_set_cpu_speed;
568 	get_speed_proc = dfs_get_cpu_speed;
569 
570 	return 0;
571 }
572 
573 static int pmac_cpufreq_init_750FX(struct device_node *cpunode)
574 {
575 	struct device_node *volt_gpio_np;
576 	u32 pvr;
577 	const u32 *value;
578 
579 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))
580 		return 1;
581 
582 	hi_freq = cur_freq;
583 	value = of_get_property(cpunode, "reduced-clock-frequency", NULL);
584 	if (!value)
585 		return 1;
586 	low_freq = (*value) / 1000;
587 
588 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
589 	if (volt_gpio_np)
590 		voltage_gpio = read_gpio(volt_gpio_np);
591 
592 	of_node_put(volt_gpio_np);
593 	pvr = mfspr(SPRN_PVR);
594 	has_cpu_l2lve = !((pvr & 0xf00) == 0x100);
595 
596 	set_speed_proc = cpu_750fx_cpu_speed;
597 	get_speed_proc = cpu_750fx_get_cpu_speed;
598 	cur_freq = cpu_750fx_get_cpu_speed();
599 
600 	return 0;
601 }
602 
603 /* Currently, we support the following machines:
604  *
605  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
606  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
607  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
608  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
609  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
610  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
611  *  - Recent MacRISC3 laptops
612  *  - All new machines with 7447A CPUs
613  */
614 static int __init pmac_cpufreq_setup(void)
615 {
616 	struct device_node	*cpunode;
617 	const u32		*value;
618 
619 	if (strstr(boot_command_line, "nocpufreq"))
620 		return 0;
621 
622 	/* Get first CPU node */
623 	cpunode = of_cpu_device_node_get(0);
624 	if (!cpunode)
625 		goto out;
626 
627 	/* Get current cpu clock freq */
628 	value = of_get_property(cpunode, "clock-frequency", NULL);
629 	if (!value)
630 		goto out;
631 	cur_freq = (*value) / 1000;
632 
633 	/*  Check for 7447A based MacRISC3 */
634 	if (of_machine_is_compatible("MacRISC3") &&
635 	    of_property_read_bool(cpunode, "dynamic-power-step") &&
636 	    PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
637 		pmac_cpufreq_init_7447A(cpunode);
638 
639 		/* Allow dynamic switching */
640 		transition_latency = 8000000;
641 		pmac_cpufreq_driver.flags &= ~CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING;
642 	/* Check for other MacRISC3 machines */
643 	} else if (of_machine_is_compatible("PowerBook3,4") ||
644 		   of_machine_is_compatible("PowerBook3,5") ||
645 		   of_machine_is_compatible("MacRISC3")) {
646 		pmac_cpufreq_init_MacRISC3(cpunode);
647 	/* Else check for iBook2 500/600 */
648 	} else if (of_machine_is_compatible("PowerBook4,1")) {
649 		hi_freq = cur_freq;
650 		low_freq = 400000;
651 		set_speed_proc = pmu_set_cpu_speed;
652 		is_pmu_based = 1;
653 	}
654 	/* Else check for TiPb 550 */
655 	else if (of_machine_is_compatible("PowerBook3,3") && cur_freq == 550000) {
656 		hi_freq = cur_freq;
657 		low_freq = 500000;
658 		set_speed_proc = pmu_set_cpu_speed;
659 		is_pmu_based = 1;
660 	}
661 	/* Else check for TiPb 400 & 500 */
662 	else if (of_machine_is_compatible("PowerBook3,2")) {
663 		/* We only know about the 400 MHz and the 500Mhz model
664 		 * they both have 300 MHz as low frequency
665 		 */
666 		if (cur_freq < 350000 || cur_freq > 550000)
667 			goto out;
668 		hi_freq = cur_freq;
669 		low_freq = 300000;
670 		set_speed_proc = pmu_set_cpu_speed;
671 		is_pmu_based = 1;
672 	}
673 	/* Else check for 750FX */
674 	else if (PVR_VER(mfspr(SPRN_PVR)) == 0x7000)
675 		pmac_cpufreq_init_750FX(cpunode);
676 out:
677 	of_node_put(cpunode);
678 	if (set_speed_proc == NULL)
679 		return -ENODEV;
680 
681 	pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
682 	pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
683 	ppc_proc_freq = cur_freq * 1000ul;
684 
685 	pr_info("Registering PowerMac CPU frequency driver\n");
686 	pr_info("Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
687 		low_freq/1000, hi_freq/1000, cur_freq/1000);
688 
689 	return cpufreq_register_driver(&pmac_cpufreq_driver);
690 }
691 
692 module_init(pmac_cpufreq_setup);
693 
694