1 // SPDX-License-Identifier: GPL-2.0-only
3  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
42  * init/main.c to make it non-init before enabling DEBUG_FREQ
51  * Currently, PowerMac cpufreq supports only high & low frequencies
109 /* Switch CPU speed under 750FX CPU control
132 		/* tweak L2 for low voltage */  in cpu_750fx_cpu_speed()
155 /* Switch CPU speed using DFS */
189 /* Switch CPU speed using slewing GPIOs
231 /* Switch CPU speed under PMU control
255 	 * the above didn't re-enable the DEC */  in pmu_set_cpu_speed()
271 	save_l3cr = _get_L3CR();	/* (returns -1 if not available) */  in pmu_set_cpu_speed()
272 	save_l2cr = _get_L2CR();	/* (returns -1 if not available) */  in pmu_set_cpu_speed()
274 	/* Send the new speed command. My assumption is that this command  in pmu_set_cpu_speed()
281 	/* Prepare the northbridge for the speed transition */  in pmu_set_cpu_speed()
284 	/* Call low level code to backup CPU state and recover from  in pmu_set_cpu_speed()
300 	switch_mmu_context(NULL, current->active_mm, NULL);  in pmu_set_cpu_speed()
306 	/* Restore low level PMU operations */  in pmu_set_cpu_speed()
311 	 * as soon as interrupts are re-enabled and the generic  in pmu_set_cpu_speed()
390 	 * GPIO space, and the device-tree doesn't help.  in read_gpio()
400 	 * always force a speed change to high speed before sleep, to make sure  in pmac_cpufreq_suspend()
401 	 * we have appropriate voltage and/or bus speed for the wakeup process,  in pmac_cpufreq_suspend()
403 	 * not cause too short delays if we sleep in low speed and wake in high  in pmac_cpufreq_suspend()
404 	 * speed..  in pmac_cpufreq_suspend()
421 	/* We don't, hrm... we don't really know our speed here, best  in pmac_cpufreq_resume()
423 	 * probably high speed due to our suspend() routine  in pmac_cpufreq_resume()
449 								"voltage-gpio");  in pmac_cpufreq_init_MacRISC3()
451 								"frequency-gpio");  in pmac_cpufreq_init_MacRISC3()
453 								     "slewing-done");  in pmac_cpufreq_init_MacRISC3()
482 		freqs = of_get_property(cpunode, "bus-frequencies", &lenp);  in pmac_cpufreq_init_MacRISC3()
485 			pr_err("bus-frequencies incorrect or missing\n");  in pmac_cpufreq_init_MacRISC3()
488 		ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",  in pmac_cpufreq_init_MacRISC3()
491 			pr_err("processor-to-bus-ratio*2 missing\n");  in pmac_cpufreq_init_MacRISC3()
499 		/* Grrrr.. It _seems_ that the device-tree is lying on the low bus  in pmac_cpufreq_init_MacRISC3()
512 		 * speed  in pmac_cpufreq_init_MacRISC3()
522 	 * device-tree  in pmac_cpufreq_init_MacRISC3()
524 	value = of_get_property(cpunode, "min-clock-frequency", NULL);  in pmac_cpufreq_init_MacRISC3()
528 	/* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree  in pmac_cpufreq_init_MacRISC3()
533 	value = of_get_property(cpunode, "max-clock-frequency", NULL);  in pmac_cpufreq_init_MacRISC3()
547 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))  in pmac_cpufreq_init_7447A()
550 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");  in pmac_cpufreq_init_7447A()
555 		pr_err("missing cpu-vcore-select gpio\n");  in pmac_cpufreq_init_7447A()
577 	if (!of_property_read_bool(cpunode, "dynamic-power-step"))  in pmac_cpufreq_init_750FX()
581 	value = of_get_property(cpunode, "reduced-clock-frequency", NULL);  in pmac_cpufreq_init_750FX()
586 	volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");  in pmac_cpufreq_init_750FX()
603  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
604  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
605  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
606  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
607  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
608  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
609  *  - Recent MacRISC3 laptops
610  *  - All new machines with 7447A CPUs
626 	value = of_get_property(cpunode, "clock-frequency", NULL);  in pmac_cpufreq_setup()
633 	    of_property_read_bool(cpunode, "dynamic-power-step") &&  in pmac_cpufreq_setup()
662 		 * they both have 300 MHz as low frequency  in pmac_cpufreq_setup()
677 		return -ENODEV;  in pmac_cpufreq_setup()
684 	pr_info("Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",  in pmac_cpufreq_setup()