xref: /linux/drivers/cpufreq/pmac32-cpufreq.c (revision ff2632d7d08edc11e8bd0629e9fcfebab25c78b4)
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 #include <linux/of_address.h>
28 
29 #include <asm/machdep.h>
30 #include <asm/irq.h>
31 #include <asm/pmac_feature.h>
32 #include <asm/mmu_context.h>
33 #include <asm/sections.h>
34 #include <asm/cputable.h>
35 #include <asm/time.h>
36 #include <asm/mpic.h>
37 #include <asm/keylargo.h>
38 #include <asm/switch_to.h>
39 
40 /* WARNING !!! This will cause calibrate_delay() to be called,
41  * but this is an __init function ! So you MUST go edit
42  * init/main.c to make it non-init before enabling DEBUG_FREQ
43  */
44 #undef DEBUG_FREQ
45 
46 extern void low_choose_7447a_dfs(int dfs);
47 extern void low_choose_750fx_pll(int pll);
48 extern void low_sleep_handler(void);
49 
50 /*
51  * Currently, PowerMac cpufreq supports only high & low frequencies
52  * that are set by the firmware
53  */
54 static unsigned int low_freq;
55 static unsigned int hi_freq;
56 static unsigned int cur_freq;
57 static unsigned int sleep_freq;
58 static unsigned long transition_latency;
59 
60 /*
61  * Different models uses different mechanisms to switch the frequency
62  */
63 static int (*set_speed_proc)(int low_speed);
64 static unsigned int (*get_speed_proc)(void);
65 
66 /*
67  * Some definitions used by the various speedprocs
68  */
69 static u32 voltage_gpio;
70 static u32 frequency_gpio;
71 static u32 slew_done_gpio;
72 static int no_schedule;
73 static int has_cpu_l2lve;
74 static int is_pmu_based;
75 
76 /* There are only two frequency states for each processor. Values
77  * are in kHz for the time being.
78  */
79 #define CPUFREQ_HIGH                  0
80 #define CPUFREQ_LOW                   1
81 
82 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
83 	{0, CPUFREQ_HIGH,	0},
84 	{0, CPUFREQ_LOW,	0},
85 	{0, 0,			CPUFREQ_TABLE_END},
86 };
87 
local_delay(unsigned long ms)88 static inline void local_delay(unsigned long ms)
89 {
90 	if (no_schedule)
91 		mdelay(ms);
92 	else
93 		msleep(ms);
94 }
95 
96 #ifdef DEBUG_FREQ
debug_calc_bogomips(void)97 static inline void debug_calc_bogomips(void)
98 {
99 	/* This will cause a recalc of bogomips and display the
100 	 * result. We backup/restore the value to avoid affecting the
101 	 * core cpufreq framework's own calculation.
102 	 */
103 	unsigned long save_lpj = loops_per_jiffy;
104 	calibrate_delay();
105 	loops_per_jiffy = save_lpj;
106 }
107 #endif /* DEBUG_FREQ */
108 
109 /* Switch CPU speed under 750FX CPU control
110  */
cpu_750fx_cpu_speed(int low_speed)111 static int cpu_750fx_cpu_speed(int low_speed)
112 {
113 	u32 hid2;
114 
115 	if (low_speed == 0) {
116 		/* ramping up, set voltage first */
117 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
118 		/* Make sure we sleep for at least 1ms */
119 		local_delay(10);
120 
121 		/* tweak L2 for high voltage */
122 		if (has_cpu_l2lve) {
123 			hid2 = mfspr(SPRN_HID2_750FX);
124 			hid2 &= ~0x2000;
125 			mtspr(SPRN_HID2_750FX, hid2);
126 		}
127 	}
128 #ifdef CONFIG_PPC_BOOK3S_32
129 	low_choose_750fx_pll(low_speed);
130 #endif
131 	if (low_speed == 1) {
132 		/* tweak L2 for low voltage */
133 		if (has_cpu_l2lve) {
134 			hid2 = mfspr(SPRN_HID2_750FX);
135 			hid2 |= 0x2000;
136 			mtspr(SPRN_HID2_750FX, hid2);
137 		}
138 
139 		/* ramping down, set voltage last */
140 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
141 		local_delay(10);
142 	}
143 
144 	return 0;
145 }
146 
cpu_750fx_get_cpu_speed(void)147 static unsigned int cpu_750fx_get_cpu_speed(void)
148 {
149 	if (mfspr(SPRN_HID1) & HID1_PS)
150 		return low_freq;
151 	else
152 		return hi_freq;
153 }
154 
155 /* Switch CPU speed using DFS */
dfs_set_cpu_speed(int low_speed)156 static int dfs_set_cpu_speed(int low_speed)
157 {
158 	if (low_speed == 0) {
159 		/* ramping up, set voltage first */
160 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
161 		/* Make sure we sleep for at least 1ms */
162 		local_delay(1);
163 	}
164 
165 	/* set frequency */
166 #ifdef CONFIG_PPC_BOOK3S_32
167 	low_choose_7447a_dfs(low_speed);
168 #endif
169 	udelay(100);
170 
171 	if (low_speed == 1) {
172 		/* ramping down, set voltage last */
173 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
174 		local_delay(1);
175 	}
176 
177 	return 0;
178 }
179 
dfs_get_cpu_speed(void)180 static unsigned int dfs_get_cpu_speed(void)
181 {
182 	if (mfspr(SPRN_HID1) & HID1_DFS)
183 		return low_freq;
184 	else
185 		return hi_freq;
186 }
187 
188 
189 /* Switch CPU speed using slewing GPIOs
190  */
gpios_set_cpu_speed(int low_speed)191 static int gpios_set_cpu_speed(int low_speed)
192 {
193 	int gpio, timeout = 0;
194 
195 	/* If ramping up, set voltage first */
196 	if (low_speed == 0) {
197 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
198 		/* Delay is way too big but it's ok, we schedule */
199 		local_delay(10);
200 	}
201 
202 	/* Set frequency */
203 	gpio = 	pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
204 	if (low_speed == ((gpio & 0x01) == 0))
205 		goto skip;
206 
207 	pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
208 			  low_speed ? 0x04 : 0x05);
209 	udelay(200);
210 	do {
211 		if (++timeout > 100)
212 			break;
213 		local_delay(1);
214 		gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
215 	} while((gpio & 0x02) == 0);
216  skip:
217 	/* If ramping down, set voltage last */
218 	if (low_speed == 1) {
219 		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
220 		/* Delay is way too big but it's ok, we schedule */
221 		local_delay(10);
222 	}
223 
224 #ifdef DEBUG_FREQ
225 	debug_calc_bogomips();
226 #endif
227 
228 	return 0;
229 }
230 
231 /* Switch CPU speed under PMU control
232  */
pmu_set_cpu_speed(int low_speed)233 static int pmu_set_cpu_speed(int low_speed)
234 {
235 	struct adb_request req;
236 	unsigned long save_l2cr;
237 	unsigned long save_l3cr;
238 	unsigned int pic_prio;
239 	unsigned long flags;
240 
241 	preempt_disable();
242 
243 #ifdef DEBUG_FREQ
244 	printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
245 #endif
246 	pmu_suspend();
247 
248 	/* Disable all interrupt sources on openpic */
249  	pic_prio = mpic_cpu_get_priority();
250 	mpic_cpu_set_priority(0xf);
251 
252 	/* Make sure the decrementer won't interrupt us */
253 	asm volatile("mtdec %0" : : "r" (0x7fffffff));
254 	/* Make sure any pending DEC interrupt occurring while we did
255 	 * the above didn't re-enable the DEC */
256 	mb();
257 	asm volatile("mtdec %0" : : "r" (0x7fffffff));
258 
259 	/* We can now disable MSR_EE */
260 	local_irq_save(flags);
261 
262 	/* Giveup the FPU & vec */
263 	enable_kernel_fp();
264 
265 #ifdef CONFIG_ALTIVEC
266 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
267 		enable_kernel_altivec();
268 #endif /* CONFIG_ALTIVEC */
269 
270 	/* Save & disable L2 and L3 caches */
271 	save_l3cr = _get_L3CR();	/* (returns -1 if not available) */
272 	save_l2cr = _get_L2CR();	/* (returns -1 if not available) */
273 
274 	/* Send the new speed command. My assumption is that this command
275 	 * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
276 	 */
277 	pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
278 	while (!req.complete)
279 		pmu_poll();
280 
281 	/* Prepare the northbridge for the speed transition */
282 	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
283 
284 	/* Call low level code to backup CPU state and recover from
285 	 * hardware reset
286 	 */
287 	low_sleep_handler();
288 
289 	/* Restore the northbridge */
290 	pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
291 
292 	/* Restore L2 cache */
293 	if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
294  		_set_L2CR(save_l2cr);
295 	/* Restore L3 cache */
296 	if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
297  		_set_L3CR(save_l3cr);
298 
299 	/* Restore userland MMU context */
300 	switch_mmu_context(NULL, current->active_mm, NULL);
301 
302 #ifdef DEBUG_FREQ
303 	printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
304 #endif
305 
306 	/* Restore low level PMU operations */
307 	pmu_unlock();
308 
309 	/*
310 	 * Restore decrementer; we'll take a decrementer interrupt
311 	 * as soon as interrupts are re-enabled and the generic
312 	 * clockevents code will reprogram it with the right value.
313 	 */
314 	set_dec(1);
315 
316 	/* Restore interrupts */
317  	mpic_cpu_set_priority(pic_prio);
318 
319 	/* Let interrupts flow again ... */
320 	local_irq_restore(flags);
321 
322 #ifdef DEBUG_FREQ
323 	debug_calc_bogomips();
324 #endif
325 
326 	pmu_resume();
327 
328 	preempt_enable();
329 
330 	return 0;
331 }
332 
do_set_cpu_speed(struct cpufreq_policy * policy,int speed_mode)333 static int do_set_cpu_speed(struct cpufreq_policy *policy, int speed_mode)
334 {
335 	unsigned long l3cr;
336 	static unsigned long prev_l3cr;
337 
338 	if (speed_mode == CPUFREQ_LOW &&
339 	    cpu_has_feature(CPU_FTR_L3CR)) {
340 		l3cr = _get_L3CR();
341 		if (l3cr & L3CR_L3E) {
342 			prev_l3cr = l3cr;
343 			_set_L3CR(0);
344 		}
345 	}
346 	set_speed_proc(speed_mode == CPUFREQ_LOW);
347 	if (speed_mode == CPUFREQ_HIGH &&
348 	    cpu_has_feature(CPU_FTR_L3CR)) {
349 		l3cr = _get_L3CR();
350 		if ((prev_l3cr & L3CR_L3E) && l3cr != prev_l3cr)
351 			_set_L3CR(prev_l3cr);
352 	}
353 	cur_freq = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
354 
355 	return 0;
356 }
357 
pmac_cpufreq_get_speed(unsigned int cpu)358 static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
359 {
360 	return cur_freq;
361 }
362 
pmac_cpufreq_target(struct cpufreq_policy * policy,unsigned int index)363 static int pmac_cpufreq_target(	struct cpufreq_policy *policy,
364 					unsigned int index)
365 {
366 	int		rc;
367 
368 	rc = do_set_cpu_speed(policy, index);
369 
370 	ppc_proc_freq = cur_freq * 1000ul;
371 	return rc;
372 }
373 
pmac_cpufreq_cpu_init(struct cpufreq_policy * policy)374 static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
375 {
376 	cpufreq_generic_init(policy, pmac_cpu_freqs, transition_latency);
377 	return 0;
378 }
379 
read_gpio(struct device_node * np)380 static u32 read_gpio(struct device_node *np)
381 {
382 	u64 offset;
383 
384 	if (of_property_read_reg(np, 0, &offset, NULL) < 0)
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 	if (offset < KEYLARGO_GPIO_LEVELS0)
393 		offset += KEYLARGO_GPIO_LEVELS0;
394 	return offset;
395 }
396 
pmac_cpufreq_suspend(struct cpufreq_policy * policy)397 static int pmac_cpufreq_suspend(struct cpufreq_policy *policy)
398 {
399 	/* Ok, this could be made a bit smarter, but let's be robust for now. We
400 	 * always force a speed change to high speed before sleep, to make sure
401 	 * we have appropriate voltage and/or bus speed for the wakeup process,
402 	 * and to make sure our loops_per_jiffies are "good enough", that is will
403 	 * not cause too short delays if we sleep in low speed and wake in high
404 	 * speed..
405 	 */
406 	no_schedule = 1;
407 	sleep_freq = cur_freq;
408 	if (cur_freq == low_freq && !is_pmu_based)
409 		do_set_cpu_speed(policy, CPUFREQ_HIGH);
410 	return 0;
411 }
412 
pmac_cpufreq_resume(struct cpufreq_policy * policy)413 static int pmac_cpufreq_resume(struct cpufreq_policy *policy)
414 {
415 	/* If we resume, first check if we have a get() function */
416 	if (get_speed_proc)
417 		cur_freq = get_speed_proc();
418 	else
419 		cur_freq = 0;
420 
421 	/* We don't, hrm... we don't really know our speed here, best
422 	 * is that we force a switch to whatever it was, which is
423 	 * probably high speed due to our suspend() routine
424 	 */
425 	do_set_cpu_speed(policy, sleep_freq == low_freq ?
426 			 CPUFREQ_LOW : CPUFREQ_HIGH);
427 
428 	ppc_proc_freq = cur_freq * 1000ul;
429 
430 	no_schedule = 0;
431 	return 0;
432 }
433 
434 static struct cpufreq_driver pmac_cpufreq_driver = {
435 	.verify 	= cpufreq_generic_frequency_table_verify,
436 	.target_index	= pmac_cpufreq_target,
437 	.get		= pmac_cpufreq_get_speed,
438 	.init		= pmac_cpufreq_cpu_init,
439 	.suspend	= pmac_cpufreq_suspend,
440 	.resume		= pmac_cpufreq_resume,
441 	.flags		= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
442 	.attr		= cpufreq_generic_attr,
443 	.name		= "powermac",
444 };
445 
446 
pmac_cpufreq_init_MacRISC3(struct device_node * cpunode)447 static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
448 {
449 	struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
450 								"voltage-gpio");
451 	struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
452 								"frequency-gpio");
453 	struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
454 								     "slewing-done");
455 	const u32 *value;
456 
457 	/*
458 	 * Check to see if it's GPIO driven or PMU only
459 	 *
460 	 * The way we extract the GPIO address is slightly hackish, but it
461 	 * works well enough for now. We need to abstract the whole GPIO
462 	 * stuff sooner or later anyway
463 	 */
464 
465 	if (volt_gpio_np)
466 		voltage_gpio = read_gpio(volt_gpio_np);
467 	if (freq_gpio_np)
468 		frequency_gpio = read_gpio(freq_gpio_np);
469 	if (slew_done_gpio_np)
470 		slew_done_gpio = read_gpio(slew_done_gpio_np);
471 
472 	of_node_put(volt_gpio_np);
473 	of_node_put(freq_gpio_np);
474 	of_node_put(slew_done_gpio_np);
475 
476 	/* If we use the frequency GPIOs, calculate the min/max speeds based
477 	 * on the bus frequencies
478 	 */
479 	if (frequency_gpio && slew_done_gpio) {
480 		int lenp, rc;
481 		const u32 *freqs, *ratio;
482 
483 		freqs = of_get_property(cpunode, "bus-frequencies", &lenp);
484 		lenp /= sizeof(u32);
485 		if (freqs == NULL || lenp != 2) {
486 			pr_err("bus-frequencies incorrect or missing\n");
487 			return 1;
488 		}
489 		ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",
490 						NULL);
491 		if (ratio == NULL) {
492 			pr_err("processor-to-bus-ratio*2 missing\n");
493 			return 1;
494 		}
495 
496 		/* Get the min/max bus frequencies */
497 		low_freq = min(freqs[0], freqs[1]);
498 		hi_freq = max(freqs[0], freqs[1]);
499 
500 		/* Grrrr.. It _seems_ that the device-tree is lying on the low bus
501 		 * frequency, it claims it to be around 84Mhz on some models while
502 		 * it appears to be approx. 101Mhz on all. Let's hack around here...
503 		 * fortunately, we don't need to be too precise
504 		 */
505 		if (low_freq < 98000000)
506 			low_freq = 101000000;
507 
508 		/* Convert those to CPU core clocks */
509 		low_freq = (low_freq * (*ratio)) / 2000;
510 		hi_freq = (hi_freq * (*ratio)) / 2000;
511 
512 		/* Now we get the frequencies, we read the GPIO to see what is out current
513 		 * speed
514 		 */
515 		rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
516 		cur_freq = (rc & 0x01) ? hi_freq : low_freq;
517 
518 		set_speed_proc = gpios_set_cpu_speed;
519 		return 1;
520 	}
521 
522 	/* If we use the PMU, look for the min & max frequencies in the
523 	 * device-tree
524 	 */
525 	value = of_get_property(cpunode, "min-clock-frequency", NULL);
526 	if (!value)
527 		return 1;
528 	low_freq = (*value) / 1000;
529 	/* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
530 	 * here */
531 	if (low_freq < 100000)
532 		low_freq *= 10;
533 
534 	value = of_get_property(cpunode, "max-clock-frequency", NULL);
535 	if (!value)
536 		return 1;
537 	hi_freq = (*value) / 1000;
538 	set_speed_proc = pmu_set_cpu_speed;
539 	is_pmu_based = 1;
540 
541 	return 0;
542 }
543 
pmac_cpufreq_init_7447A(struct device_node * cpunode)544 static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
545 {
546 	struct device_node *volt_gpio_np;
547 
548 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))
549 		return 1;
550 
551 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
552 	if (volt_gpio_np)
553 		voltage_gpio = read_gpio(volt_gpio_np);
554 	of_node_put(volt_gpio_np);
555 	if (!voltage_gpio){
556 		pr_err("missing cpu-vcore-select gpio\n");
557 		return 1;
558 	}
559 
560 	/* OF only reports the high frequency */
561 	hi_freq = cur_freq;
562 	low_freq = cur_freq/2;
563 
564 	/* Read actual frequency from CPU */
565 	cur_freq = dfs_get_cpu_speed();
566 	set_speed_proc = dfs_set_cpu_speed;
567 	get_speed_proc = dfs_get_cpu_speed;
568 
569 	return 0;
570 }
571 
pmac_cpufreq_init_750FX(struct device_node * cpunode)572 static int pmac_cpufreq_init_750FX(struct device_node *cpunode)
573 {
574 	struct device_node *volt_gpio_np;
575 	u32 pvr;
576 	const u32 *value;
577 
578 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))
579 		return 1;
580 
581 	hi_freq = cur_freq;
582 	value = of_get_property(cpunode, "reduced-clock-frequency", NULL);
583 	if (!value)
584 		return 1;
585 	low_freq = (*value) / 1000;
586 
587 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
588 	if (volt_gpio_np)
589 		voltage_gpio = read_gpio(volt_gpio_np);
590 
591 	of_node_put(volt_gpio_np);
592 	pvr = mfspr(SPRN_PVR);
593 	has_cpu_l2lve = !((pvr & 0xf00) == 0x100);
594 
595 	set_speed_proc = cpu_750fx_cpu_speed;
596 	get_speed_proc = cpu_750fx_get_cpu_speed;
597 	cur_freq = cpu_750fx_get_cpu_speed();
598 
599 	return 0;
600 }
601 
602 /* Currently, we support the following machines:
603  *
604  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
605  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
606  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
607  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
608  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
609  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
610  *  - Recent MacRISC3 laptops
611  *  - All new machines with 7447A CPUs
612  */
pmac_cpufreq_setup(void)613 static int __init pmac_cpufreq_setup(void)
614 {
615 	struct device_node	*cpunode;
616 	const u32		*value;
617 
618 	if (strstr(boot_command_line, "nocpufreq"))
619 		return 0;
620 
621 	/* Get first CPU node */
622 	cpunode = of_cpu_device_node_get(0);
623 	if (!cpunode)
624 		goto out;
625 
626 	/* Get current cpu clock freq */
627 	value = of_get_property(cpunode, "clock-frequency", NULL);
628 	if (!value)
629 		goto out;
630 	cur_freq = (*value) / 1000;
631 
632 	/*  Check for 7447A based MacRISC3 */
633 	if (of_machine_is_compatible("MacRISC3") &&
634 	    of_property_read_bool(cpunode, "dynamic-power-step") &&
635 	    PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
636 		pmac_cpufreq_init_7447A(cpunode);
637 
638 		/* Allow dynamic switching */
639 		transition_latency = 8000000;
640 		pmac_cpufreq_driver.flags &= ~CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING;
641 	/* Check for other MacRISC3 machines */
642 	} else if (of_machine_is_compatible("PowerBook3,4") ||
643 		   of_machine_is_compatible("PowerBook3,5") ||
644 		   of_machine_is_compatible("MacRISC3")) {
645 		pmac_cpufreq_init_MacRISC3(cpunode);
646 	/* Else check for iBook2 500/600 */
647 	} else if (of_machine_is_compatible("PowerBook4,1")) {
648 		hi_freq = cur_freq;
649 		low_freq = 400000;
650 		set_speed_proc = pmu_set_cpu_speed;
651 		is_pmu_based = 1;
652 	}
653 	/* Else check for TiPb 550 */
654 	else if (of_machine_is_compatible("PowerBook3,3") && cur_freq == 550000) {
655 		hi_freq = cur_freq;
656 		low_freq = 500000;
657 		set_speed_proc = pmu_set_cpu_speed;
658 		is_pmu_based = 1;
659 	}
660 	/* Else check for TiPb 400 & 500 */
661 	else if (of_machine_is_compatible("PowerBook3,2")) {
662 		/* We only know about the 400 MHz and the 500Mhz model
663 		 * they both have 300 MHz as low frequency
664 		 */
665 		if (cur_freq < 350000 || cur_freq > 550000)
666 			goto out;
667 		hi_freq = cur_freq;
668 		low_freq = 300000;
669 		set_speed_proc = pmu_set_cpu_speed;
670 		is_pmu_based = 1;
671 	}
672 	/* Else check for 750FX */
673 	else if (PVR_VER(mfspr(SPRN_PVR)) == 0x7000)
674 		pmac_cpufreq_init_750FX(cpunode);
675 out:
676 	of_node_put(cpunode);
677 	if (set_speed_proc == NULL)
678 		return -ENODEV;
679 
680 	pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
681 	pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
682 	ppc_proc_freq = cur_freq * 1000ul;
683 
684 	pr_info("Registering PowerMac CPU frequency driver\n");
685 	pr_info("Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
686 		low_freq/1000, hi_freq/1000, cur_freq/1000);
687 
688 	return cpufreq_register_driver(&pmac_cpufreq_driver);
689 }
690 
691 module_init(pmac_cpufreq_setup);
692 
693