GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / pmac32-cpufreq.c
1 /*
2  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
3  *  Copyright (C) 2004        John Steele Scott <toojays@toojays.net>
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  * TODO: Need a big cleanup here. Basically, we need to have different
10  * cpufreq_driver structures for the different type of HW instead of the
11  * current mess. We also need to better deal with the detection of the
12  * type of machine.
13  *
14  */
15
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/delay.h>
21 #include <linux/sched.h>
22 #include <linux/adb.h>
23 #include <linux/pmu.h>
24 #include <linux/cpufreq.h>
25 #include <linux/init.h>
26 #include <linux/device.h>
27 #include <linux/hardirq.h>
28 #include <linux/of_device.h>
29 #include <asm/prom.h>
30 #include <asm/machdep.h>
31 #include <asm/irq.h>
32 #include <asm/pmac_feature.h>
33 #include <asm/mmu_context.h>
34 #include <asm/sections.h>
35 #include <asm/cputable.h>
36 #include <asm/time.h>
37 #include <asm/mpic.h>
38 #include <asm/keylargo.h>
39 #include <asm/switch_to.h>
40
41 /* WARNING !!! This will cause calibrate_delay() to be called,
42  * but this is an __init function ! So you MUST go edit
43  * init/main.c to make it non-init before enabling DEBUG_FREQ
44  */
45 #undef DEBUG_FREQ
46
47 extern void low_choose_7447a_dfs(int dfs);
48 extern void low_choose_750fx_pll(int pll);
49 extern void low_sleep_handler(void);
50
51 /*
52  * Currently, PowerMac cpufreq supports only high & low frequencies
53  * that are set by the firmware
54  */
55 static unsigned int low_freq;
56 static unsigned int hi_freq;
57 static unsigned int cur_freq;
58 static unsigned int sleep_freq;
59 static unsigned long transition_latency;
60
61 /*
62  * Different models uses different mechanisms to switch the frequency
63  */
64 static int (*set_speed_proc)(int low_speed);
65 static unsigned int (*get_speed_proc)(void);
66
67 /*
68  * Some definitions used by the various speedprocs
69  */
70 static u32 voltage_gpio;
71 static u32 frequency_gpio;
72 static u32 slew_done_gpio;
73 static int no_schedule;
74 static int has_cpu_l2lve;
75 static int is_pmu_based;
76
77 /* There are only two frequency states for each processor. Values
78  * are in kHz for the time being.
79  */
80 #define CPUFREQ_HIGH                  0
81 #define CPUFREQ_LOW                   1
82
83 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
84         {0, CPUFREQ_HIGH,       0},
85         {0, CPUFREQ_LOW,        0},
86         {0, 0,                  CPUFREQ_TABLE_END},
87 };
88
89 static inline void local_delay(unsigned long ms)
90 {
91         if (no_schedule)
92                 mdelay(ms);
93         else
94                 msleep(ms);
95 }
96
97 #ifdef DEBUG_FREQ
98 static inline void debug_calc_bogomips(void)
99 {
100         /* This will cause a recalc of bogomips and display the
101          * result. We backup/restore the value to avoid affecting the
102          * core cpufreq framework's own calculation.
103          */
104         unsigned long save_lpj = loops_per_jiffy;
105         calibrate_delay();
106         loops_per_jiffy = save_lpj;
107 }
108 #endif /* DEBUG_FREQ */
109
110 /* Switch CPU speed under 750FX CPU control
111  */
112 static int cpu_750fx_cpu_speed(int low_speed)
113 {
114         u32 hid2;
115
116         if (low_speed == 0) {
117                 /* ramping up, set voltage first */
118                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
119                 /* Make sure we sleep for at least 1ms */
120                 local_delay(10);
121
122                 /* tweak L2 for high voltage */
123                 if (has_cpu_l2lve) {
124                         hid2 = mfspr(SPRN_HID2);
125                         hid2 &= ~0x2000;
126                         mtspr(SPRN_HID2, hid2);
127                 }
128         }
129 #ifdef CONFIG_6xx
130         low_choose_750fx_pll(low_speed);
131 #endif
132         if (low_speed == 1) {
133                 /* tweak L2 for low voltage */
134                 if (has_cpu_l2lve) {
135                         hid2 = mfspr(SPRN_HID2);
136                         hid2 |= 0x2000;
137                         mtspr(SPRN_HID2, hid2);
138                 }
139
140                 /* ramping down, set voltage last */
141                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
142                 local_delay(10);
143         }
144
145         return 0;
146 }
147
148 static unsigned int cpu_750fx_get_cpu_speed(void)
149 {
150         if (mfspr(SPRN_HID1) & HID1_PS)
151                 return low_freq;
152         else
153                 return hi_freq;
154 }
155
156 /* Switch CPU speed using DFS */
157 static int dfs_set_cpu_speed(int low_speed)
158 {
159         if (low_speed == 0) {
160                 /* ramping up, set voltage first */
161                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
162                 /* Make sure we sleep for at least 1ms */
163                 local_delay(1);
164         }
165
166         /* set frequency */
167 #ifdef CONFIG_6xx
168         low_choose_7447a_dfs(low_speed);
169 #endif
170         udelay(100);
171
172         if (low_speed == 1) {
173                 /* ramping down, set voltage last */
174                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
175                 local_delay(1);
176         }
177
178         return 0;
179 }
180
181 static unsigned int dfs_get_cpu_speed(void)
182 {
183         if (mfspr(SPRN_HID1) & HID1_DFS)
184                 return low_freq;
185         else
186                 return hi_freq;
187 }
188
189
190 /* Switch CPU speed using slewing GPIOs
191  */
192 static int gpios_set_cpu_speed(int low_speed)
193 {
194         int gpio, timeout = 0;
195
196         /* If ramping up, set voltage first */
197         if (low_speed == 0) {
198                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
199                 /* Delay is way too big but it's ok, we schedule */
200                 local_delay(10);
201         }
202
203         /* Set frequency */
204         gpio =  pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
205         if (low_speed == ((gpio & 0x01) == 0))
206                 goto skip;
207
208         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
209                           low_speed ? 0x04 : 0x05);
210         udelay(200);
211         do {
212                 if (++timeout > 100)
213                         break;
214                 local_delay(1);
215                 gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
216         } while((gpio & 0x02) == 0);
217  skip:
218         /* If ramping down, set voltage last */
219         if (low_speed == 1) {
220                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
221                 /* Delay is way too big but it's ok, we schedule */
222                 local_delay(10);
223         }
224
225 #ifdef DEBUG_FREQ
226         debug_calc_bogomips();
227 #endif
228
229         return 0;
230 }
231
232 /* Switch CPU speed under PMU control
233  */
234 static int pmu_set_cpu_speed(int low_speed)
235 {
236         struct adb_request req;
237         unsigned long save_l2cr;
238         unsigned long save_l3cr;
239         unsigned int pic_prio;
240         unsigned long flags;
241
242         preempt_disable();
243
244 #ifdef DEBUG_FREQ
245         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
246 #endif
247         pmu_suspend();
248
249         /* Disable all interrupt sources on openpic */
250         pic_prio = mpic_cpu_get_priority();
251         mpic_cpu_set_priority(0xf);
252
253         /* Make sure the decrementer won't interrupt us */
254         asm volatile("mtdec %0" : : "r" (0x7fffffff));
255         /* Make sure any pending DEC interrupt occurring while we did
256          * the above didn't re-enable the DEC */
257         mb();
258         asm volatile("mtdec %0" : : "r" (0x7fffffff));
259
260         /* We can now disable MSR_EE */
261         local_irq_save(flags);
262
263         /* Giveup the FPU & vec */
264         enable_kernel_fp();
265
266 #ifdef CONFIG_ALTIVEC
267         if (cpu_has_feature(CPU_FTR_ALTIVEC))
268                 enable_kernel_altivec();
269 #endif /* CONFIG_ALTIVEC */
270
271         /* Save & disable L2 and L3 caches */
272         save_l3cr = _get_L3CR();        /* (returns -1 if not available) */
273         save_l2cr = _get_L2CR();        /* (returns -1 if not available) */
274
275         /* Send the new speed command. My assumption is that this command
276          * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
277          */
278         pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
279         while (!req.complete)
280                 pmu_poll();
281
282         /* Prepare the northbridge for the speed transition */
283         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
284
285         /* Call low level code to backup CPU state and recover from
286          * hardware reset
287          */
288         low_sleep_handler();
289
290         /* Restore the northbridge */
291         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
292
293         /* Restore L2 cache */
294         if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
295                 _set_L2CR(save_l2cr);
296         /* Restore L3 cache */
297         if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
298                 _set_L3CR(save_l3cr);
299
300         /* Restore userland MMU context */
301         switch_mmu_context(NULL, current->active_mm);
302
303 #ifdef DEBUG_FREQ
304         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
305 #endif
306
307         /* Restore low level PMU operations */
308         pmu_unlock();
309
310         /*
311          * Restore decrementer; we'll take a decrementer interrupt
312          * as soon as interrupts are re-enabled and the generic
313          * clockevents code will reprogram it with the right value.
314          */
315         set_dec(1);
316
317         /* Restore interrupts */
318         mpic_cpu_set_priority(pic_prio);
319
320         /* Let interrupts flow again ... */
321         local_irq_restore(flags);
322
323 #ifdef DEBUG_FREQ
324         debug_calc_bogomips();
325 #endif
326
327         pmu_resume();
328
329         preempt_enable();
330
331         return 0;
332 }
333
334 static int do_set_cpu_speed(struct cpufreq_policy *policy, int speed_mode)
335 {
336         unsigned long l3cr;
337         static unsigned long prev_l3cr;
338
339         if (speed_mode == CPUFREQ_LOW &&
340             cpu_has_feature(CPU_FTR_L3CR)) {
341                 l3cr = _get_L3CR();
342                 if (l3cr & L3CR_L3E) {
343                         prev_l3cr = l3cr;
344                         _set_L3CR(0);
345                 }
346         }
347         set_speed_proc(speed_mode == CPUFREQ_LOW);
348         if (speed_mode == CPUFREQ_HIGH &&
349             cpu_has_feature(CPU_FTR_L3CR)) {
350                 l3cr = _get_L3CR();
351                 if ((prev_l3cr & L3CR_L3E) && l3cr != prev_l3cr)
352                         _set_L3CR(prev_l3cr);
353         }
354         cur_freq = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
355
356         return 0;
357 }
358
359 static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
360 {
361         return cur_freq;
362 }
363
364 static int pmac_cpufreq_target( struct cpufreq_policy *policy,
365                                         unsigned int index)
366 {
367         int             rc;
368
369         rc = do_set_cpu_speed(policy, index);
370
371         ppc_proc_freq = cur_freq * 1000ul;
372         return rc;
373 }
374
375 static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
376 {
377         return cpufreq_generic_init(policy, pmac_cpu_freqs, transition_latency);
378 }
379
380 static u32 read_gpio(struct device_node *np)
381 {
382         const u32 *reg = of_get_property(np, "reg", NULL);
383         u32 offset;
384
385         if (reg == NULL)
386                 return 0;
387         /* That works for all keylargos but shall be fixed properly
388          * some day... The problem is that it seems we can't rely
389          * on the "reg" property of the GPIO nodes, they are either
390          * relative to the base of KeyLargo or to the base of the
391          * GPIO space, and the device-tree doesn't help.
392          */
393         offset = *reg;
394         if (offset < KEYLARGO_GPIO_LEVELS0)
395                 offset += KEYLARGO_GPIO_LEVELS0;
396         return offset;
397 }
398
399 static int pmac_cpufreq_suspend(struct cpufreq_policy *policy)
400 {
401         /* Ok, this could be made a bit smarter, but let's be robust for now. We
402          * always force a speed change to high speed before sleep, to make sure
403          * we have appropriate voltage and/or bus speed for the wakeup process,
404          * and to make sure our loops_per_jiffies are "good enough", that is will
405          * not cause too short delays if we sleep in low speed and wake in high
406          * speed..
407          */
408         no_schedule = 1;
409         sleep_freq = cur_freq;
410         if (cur_freq == low_freq && !is_pmu_based)
411                 do_set_cpu_speed(policy, CPUFREQ_HIGH);
412         return 0;
413 }
414
415 static int pmac_cpufreq_resume(struct cpufreq_policy *policy)
416 {
417         /* If we resume, first check if we have a get() function */
418         if (get_speed_proc)
419                 cur_freq = get_speed_proc();
420         else
421                 cur_freq = 0;
422
423         /* We don't, hrm... we don't really know our speed here, best
424          * is that we force a switch to whatever it was, which is
425          * probably high speed due to our suspend() routine
426          */
427         do_set_cpu_speed(policy, sleep_freq == low_freq ?
428                          CPUFREQ_LOW : CPUFREQ_HIGH);
429
430         ppc_proc_freq = cur_freq * 1000ul;
431
432         no_schedule = 0;
433         return 0;
434 }
435
436 static struct cpufreq_driver pmac_cpufreq_driver = {
437         .verify         = cpufreq_generic_frequency_table_verify,
438         .target_index   = pmac_cpufreq_target,
439         .get            = pmac_cpufreq_get_speed,
440         .init           = pmac_cpufreq_cpu_init,
441         .suspend        = pmac_cpufreq_suspend,
442         .resume         = pmac_cpufreq_resume,
443         .flags          = CPUFREQ_PM_NO_WARN,
444         .attr           = cpufreq_generic_attr,
445         .name           = "powermac",
446 };
447
448
449 static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
450 {
451         struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
452                                                                 "voltage-gpio");
453         struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
454                                                                 "frequency-gpio");
455         struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
456                                                                      "slewing-done");
457         const u32 *value;
458
459         /*
460          * Check to see if it's GPIO driven or PMU only
461          *
462          * The way we extract the GPIO address is slightly hackish, but it
463          * works well enough for now. We need to abstract the whole GPIO
464          * stuff sooner or later anyway
465          */
466
467         if (volt_gpio_np)
468                 voltage_gpio = read_gpio(volt_gpio_np);
469         if (freq_gpio_np)
470                 frequency_gpio = read_gpio(freq_gpio_np);
471         if (slew_done_gpio_np)
472                 slew_done_gpio = read_gpio(slew_done_gpio_np);
473
474         /* If we use the frequency GPIOs, calculate the min/max speeds based
475          * on the bus frequencies
476          */
477         if (frequency_gpio && slew_done_gpio) {
478                 int lenp, rc;
479                 const u32 *freqs, *ratio;
480
481                 freqs = of_get_property(cpunode, "bus-frequencies", &lenp);
482                 lenp /= sizeof(u32);
483                 if (freqs == NULL || lenp != 2) {
484                         printk(KERN_ERR "cpufreq: bus-frequencies incorrect or missing\n");
485                         return 1;
486                 }
487                 ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",
488                                                 NULL);
489                 if (ratio == NULL) {
490                         printk(KERN_ERR "cpufreq: processor-to-bus-ratio*2 missing\n");
491                         return 1;
492                 }
493
494                 /* Get the min/max bus frequencies */
495                 low_freq = min(freqs[0], freqs[1]);
496                 hi_freq = max(freqs[0], freqs[1]);
497
498                 /* Grrrr.. It _seems_ that the device-tree is lying on the low bus
499                  * frequency, it claims it to be around 84Mhz on some models while
500                  * it appears to be approx. 101Mhz on all. Let's hack around here...
501                  * fortunately, we don't need to be too precise
502                  */
503                 if (low_freq < 98000000)
504                         low_freq = 101000000;
505
506                 /* Convert those to CPU core clocks */
507                 low_freq = (low_freq * (*ratio)) / 2000;
508                 hi_freq = (hi_freq * (*ratio)) / 2000;
509
510                 /* Now we get the frequencies, we read the GPIO to see what is out current
511                  * speed
512                  */
513                 rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
514                 cur_freq = (rc & 0x01) ? hi_freq : low_freq;
515
516                 set_speed_proc = gpios_set_cpu_speed;
517                 return 1;
518         }
519
520         /* If we use the PMU, look for the min & max frequencies in the
521          * device-tree
522          */
523         value = of_get_property(cpunode, "min-clock-frequency", NULL);
524         if (!value)
525                 return 1;
526         low_freq = (*value) / 1000;
527         /* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
528          * here */
529         if (low_freq < 100000)
530                 low_freq *= 10;
531
532         value = of_get_property(cpunode, "max-clock-frequency", NULL);
533         if (!value)
534                 return 1;
535         hi_freq = (*value) / 1000;
536         set_speed_proc = pmu_set_cpu_speed;
537         is_pmu_based = 1;
538
539         return 0;
540 }
541
542 static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
543 {
544         struct device_node *volt_gpio_np;
545
546         if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
547                 return 1;
548
549         volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
550         if (volt_gpio_np)
551                 voltage_gpio = read_gpio(volt_gpio_np);
552         of_node_put(volt_gpio_np);
553         if (!voltage_gpio){
554                 printk(KERN_ERR "cpufreq: missing cpu-vcore-select gpio\n");
555                 return 1;
556         }
557
558         /* OF only reports the high frequency */
559         hi_freq = cur_freq;
560         low_freq = cur_freq/2;
561
562         /* Read actual frequency from CPU */
563         cur_freq = dfs_get_cpu_speed();
564         set_speed_proc = dfs_set_cpu_speed;
565         get_speed_proc = dfs_get_cpu_speed;
566
567         return 0;
568 }
569
570 static int pmac_cpufreq_init_750FX(struct device_node *cpunode)
571 {
572         struct device_node *volt_gpio_np;
573         u32 pvr;
574         const u32 *value;
575
576         if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
577                 return 1;
578
579         hi_freq = cur_freq;
580         value = of_get_property(cpunode, "reduced-clock-frequency", NULL);
581         if (!value)
582                 return 1;
583         low_freq = (*value) / 1000;
584
585         volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
586         if (volt_gpio_np)
587                 voltage_gpio = read_gpio(volt_gpio_np);
588
589         of_node_put(volt_gpio_np);
590         pvr = mfspr(SPRN_PVR);
591         has_cpu_l2lve = !((pvr & 0xf00) == 0x100);
592
593         set_speed_proc = cpu_750fx_cpu_speed;
594         get_speed_proc = cpu_750fx_get_cpu_speed;
595         cur_freq = cpu_750fx_get_cpu_speed();
596
597         return 0;
598 }
599
600 /* Currently, we support the following machines:
601  *
602  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
603  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
604  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
605  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
606  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
607  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
608  *  - Recent MacRISC3 laptops
609  *  - All new machines with 7447A CPUs
610  */
611 static int __init pmac_cpufreq_setup(void)
612 {
613         struct device_node      *cpunode;
614         const u32               *value;
615
616         if (strstr(boot_command_line, "nocpufreq"))
617                 return 0;
618
619         /* Get first CPU node */
620         cpunode = of_cpu_device_node_get(0);
621         if (!cpunode)
622                 goto out;
623
624         /* Get current cpu clock freq */
625         value = of_get_property(cpunode, "clock-frequency", NULL);
626         if (!value)
627                 goto out;
628         cur_freq = (*value) / 1000;
629         transition_latency = CPUFREQ_ETERNAL;
630
631         /*  Check for 7447A based MacRISC3 */
632         if (of_machine_is_compatible("MacRISC3") &&
633             of_get_property(cpunode, "dynamic-power-step", NULL) &&
634             PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
635                 pmac_cpufreq_init_7447A(cpunode);
636                 transition_latency = 8000000;
637         /* Check for other MacRISC3 machines */
638         } else if (of_machine_is_compatible("PowerBook3,4") ||
639                    of_machine_is_compatible("PowerBook3,5") ||
640                    of_machine_is_compatible("MacRISC3")) {
641                 pmac_cpufreq_init_MacRISC3(cpunode);
642         /* Else check for iBook2 500/600 */
643         } else if (of_machine_is_compatible("PowerBook4,1")) {
644                 hi_freq = cur_freq;
645                 low_freq = 400000;
646                 set_speed_proc = pmu_set_cpu_speed;
647                 is_pmu_based = 1;
648         }
649         /* Else check for TiPb 550 */
650         else if (of_machine_is_compatible("PowerBook3,3") && cur_freq == 550000) {
651                 hi_freq = cur_freq;
652                 low_freq = 500000;
653                 set_speed_proc = pmu_set_cpu_speed;
654                 is_pmu_based = 1;
655         }
656         /* Else check for TiPb 400 & 500 */
657         else if (of_machine_is_compatible("PowerBook3,2")) {
658                 /* We only know about the 400 MHz and the 500Mhz model
659                  * they both have 300 MHz as low frequency
660                  */
661                 if (cur_freq < 350000 || cur_freq > 550000)
662                         goto out;
663                 hi_freq = cur_freq;
664                 low_freq = 300000;
665                 set_speed_proc = pmu_set_cpu_speed;
666                 is_pmu_based = 1;
667         }
668         /* Else check for 750FX */
669         else if (PVR_VER(mfspr(SPRN_PVR)) == 0x7000)
670                 pmac_cpufreq_init_750FX(cpunode);
671 out:
672         of_node_put(cpunode);
673         if (set_speed_proc == NULL)
674                 return -ENODEV;
675
676         pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
677         pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
678         ppc_proc_freq = cur_freq * 1000ul;
679
680         printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
681         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
682                low_freq/1000, hi_freq/1000, cur_freq/1000);
683
684         return cpufreq_register_driver(&pmac_cpufreq_driver);
685 }
686
687 module_init(pmac_cpufreq_setup);
688