1 // SPDX-License-Identifier: GPL-2.0
3  * temp.c	Thermal management for cpu's with Thermal Assist Units
8  * dynamic power management to limit peak CPU temp (using ICTC)
11  * Silly, crazy ideas: use cpu load (from scheduler) and ICTC to extend battery
55 static void set_thresholds(unsigned long cpu)  in set_thresholds()  argument
60 	mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | maybe_tie | THRM1_TID);  in set_thresholds()
63 	mtspr(SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V | maybe_tie);  in set_thresholds()
66 static void TAUupdate(int cpu)  in TAUupdate()  argument
77 		if (tau[cpu].low >= step_size) {  in TAUupdate()
78 			tau[cpu].low -= step_size;  in TAUupdate()
79 			tau[cpu].high -= (step_size - window_expand);  in TAUupdate()
81 		tau[cpu].grew = 1;  in TAUupdate()
88 		if (tau[cpu].high <= 127 - step_size) {  in TAUupdate()
89 			tau[cpu].low += (step_size - window_expand);  in TAUupdate()
90 			tau[cpu].high += step_size;  in TAUupdate()
92 		tau[cpu].grew = 1;  in TAUupdate()
99  * TAU interrupts - called when we have a thermal assist unit interrupt
105 	int cpu = smp_processor_id();  in DEFINE_INTERRUPT_HANDLER_ASYNC()  local
107 	tau[cpu].interrupts++;  in DEFINE_INTERRUPT_HANDLER_ASYNC()
109 	TAUupdate(cpu);  in DEFINE_INTERRUPT_HANDLER_ASYNC()
115 	int cpu;  in tau_timeout()  local
119 	cpu = smp_processor_id();  in tau_timeout()
122 		TAUupdate(cpu);  in tau_timeout()
124 	/* Stop thermal sensor comparisons and interrupts */  in tau_timeout()
127 	size = tau[cpu].high - tau[cpu].low;  in tau_timeout()
128 	if (size > min_window && ! tau[cpu].grew) {  in tau_timeout()
130 		shrink = (2 + size - min_window) / 4;  in tau_timeout()
132 			tau[cpu].low += shrink;  in tau_timeout()
133 			tau[cpu].high -= shrink;  in tau_timeout()
135 			tau[cpu].low += 1;  in tau_timeout()
137 			if ((tau[cpu].high - tau[cpu].low) != min_window){  in tau_timeout()
144 	tau[cpu].grew = 0;  in tau_timeout()
146 	set_thresholds(cpu);  in tau_timeout()
148 	/* Restart thermal sensor comparisons and interrupts.  in tau_timeout()
179 	unsigned long cpu = smp_processor_id();  in TAU_init_smp()  local
183 	tau[cpu].low = 5;  in TAU_init_smp()
184 	tau[cpu].high = 120;  in TAU_init_smp()
186 	set_thresholds(cpu);  in TAU_init_smp()
191 	/* We assume in SMP that if one CPU has TAU support, they  in TAU_init()
192 	 * all have it --BenH  in TAU_init()
195 		printk("Thermal assist unit not available\n");  in TAU_init()
201 			 !strcmp(cur_cpu_spec->platform, "ppc750");  in TAU_init()
205 		return -ENOMEM;  in TAU_init()
211 	pr_info("Thermal assist unit using %s, shrink_timer: %d ms\n",  in TAU_init()
224 u32 cpu_temp_both(unsigned long cpu)  in cpu_temp_both()  argument
226 	return ((tau[cpu].high << 16) | tau[cpu].low);  in cpu_temp_both()
229 u32 cpu_temp(unsigned long cpu)  in cpu_temp()  argument
231 	return ((tau[cpu].high + tau[cpu].low) / 2);  in cpu_temp()
234 u32 tau_interrupts(unsigned long cpu)  in tau_interrupts()  argument
236 	return (tau[cpu].interrupts);  in tau_interrupts()