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
46extern void low_choose_7447a_dfs(int dfs);
47extern void low_choose_750fx_pll(int pll);
48extern void low_sleep_handler(void);
49
50/*
51 * Currently, PowerMac cpufreq supports only high & low frequencies
52 * that are set by the firmware
53 */
54static unsigned int low_freq;
55static unsigned int hi_freq;
56static unsigned int cur_freq;
57static unsigned int sleep_freq;
58static unsigned long transition_latency;
59
60/*
61 * Different models uses different mechanisms to switch the frequency
62 */
63static int (*set_speed_proc)(int low_speed);
64static unsigned int (*get_speed_proc)(void);
65
66/*
67 * Some definitions used by the various speedprocs
68 */
69static u32 voltage_gpio;
70static u32 frequency_gpio;
71static u32 slew_done_gpio;
72static int no_schedule;
73static int has_cpu_l2lve;
74static 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
82static 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
88static inline void local_delay(unsigned long ms)
89{
90 if (no_schedule)
91 mdelay(ms);
92 else
93 msleep(msecs: ms);
94}
95
96#ifdef DEBUG_FREQ
97static 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 */
111static 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(ms: 10);
120
121 /* tweak L2 for high voltage */
122 if (has_cpu_l2lve) {
123 hid2 = mfspr(SPRN_HID2);
124 hid2 &= ~0x2000;
125 mtspr(SPRN_HID2, 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);
135 hid2 |= 0x2000;
136 mtspr(SPRN_HID2, hid2);
137 }
138
139 /* ramping down, set voltage last */
140 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
141 local_delay(ms: 10);
142 }
143
144 return 0;
145}
146
147static 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 */
156static 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(ms: 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(ms: 1);
175 }
176
177 return 0;
178}
179
180static 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 */
191static 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(ms: 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(ms: 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(ms: 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 */
233static 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: &req, NULL, nbytes: 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
333static 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
358static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
359{
360 return cur_freq;
361}
362
363static int pmac_cpufreq_target( struct cpufreq_policy *policy,
364 unsigned int index)
365{
366 int rc;
367
368 rc = do_set_cpu_speed(policy, speed_mode: index);
369
370 ppc_proc_freq = cur_freq * 1000ul;
371 return rc;
372}
373
374static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
375{
376 cpufreq_generic_init(policy, table: pmac_cpu_freqs, transition_latency);
377 return 0;
378}
379
380static u32 read_gpio(struct device_node *np)
381{
382 u64 offset;
383
384 if (of_property_read_reg(np, idx: 0, addr: &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
397static 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
413static 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, speed_mode: 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
434static 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
447static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
448{
449 struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
450 name: "voltage-gpio");
451 struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
452 name: "frequency-gpio");
453 struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
454 name: "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(np: volt_gpio_np);
467 if (freq_gpio_np)
468 frequency_gpio = read_gpio(np: freq_gpio_np);
469 if (slew_done_gpio_np)
470 slew_done_gpio = read_gpio(np: slew_done_gpio_np);
471
472 of_node_put(node: volt_gpio_np);
473 of_node_put(node: freq_gpio_np);
474 of_node_put(node: 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(node: cpunode, name: "bus-frequencies", lenp: &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(node: cpunode, name: "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(node: cpunode, name: "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(node: cpunode, name: "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
544static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
545{
546 struct device_node *volt_gpio_np;
547
548 if (!of_property_read_bool(np: cpunode, propname: "dynamic-power-step"))
549 return 1;
550
551 volt_gpio_np = of_find_node_by_name(NULL, name: "cpu-vcore-select");
552 if (volt_gpio_np)
553 voltage_gpio = read_gpio(np: volt_gpio_np);
554 of_node_put(node: 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
572static 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(np: cpunode, propname: "dynamic-power-step"))
579 return 1;
580
581 hi_freq = cur_freq;
582 value = of_get_property(node: cpunode, name: "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, name: "cpu-vcore-select");
588 if (volt_gpio_np)
589 voltage_gpio = read_gpio(np: volt_gpio_np);
590
591 of_node_put(node: 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 */
613static 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(cpu: 0);
623 if (!cpunode)
624 goto out;
625
626 /* Get current cpu clock freq */
627 value = of_get_property(node: cpunode, name: "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(compat: "PowerBook3,4") ||
643 of_machine_is_compatible(compat: "PowerBook3,5") ||
644 of_machine_is_compatible(compat: "MacRISC3")) {
645 pmac_cpufreq_init_MacRISC3(cpunode);
646 /* Else check for iBook2 500/600 */
647 } else if (of_machine_is_compatible(compat: "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(compat: "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(compat: "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);
675out:
676 of_node_put(node: 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(driver_data: &pmac_cpufreq_driver);
689}
690
691module_init(pmac_cpufreq_setup);
692
693

source code of linux/drivers/cpufreq/pmac32-cpufreq.c