1 // SPDX-License-Identifier: GPL-2.0-or-later
3  *	Pentium 4/Xeon CPU on demand clock modulation/speed scaling
4  *	(C) 2002 - 2003 Dominik Brodowski <[email protected]>
12  *      software is provided AS-IS with no warranties.
33 #include "speedstep-lib.h"
50 static unsigned int cpufreq_p4_get(unsigned int cpu);
52 static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)  in cpufreq_p4_setdc()  argument
57 		return -EINVAL;  in cpufreq_p4_setdc()
59 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);  in cpufreq_p4_setdc()
62 		pr_debug("CPU#%d currently thermal throttled\n", cpu);  in cpufreq_p4_setdc()
64 	if (has_N44_O17_errata[cpu] &&  in cpufreq_p4_setdc()
68 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);  in cpufreq_p4_setdc()
70 		pr_debug("CPU#%d disabling modulation\n", cpu);  in cpufreq_p4_setdc()
71 		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);  in cpufreq_p4_setdc()
73 		pr_debug("CPU#%d setting duty cycle to %d%%\n",  in cpufreq_p4_setdc()
74 			cpu, ((125 * newstate) / 10));  in cpufreq_p4_setdc()
75 		/* bits 63 - 5	: reserved  in cpufreq_p4_setdc()
76 		 * bit  4	: enable/disable  in cpufreq_p4_setdc()
77 		 * bits 3-1	: duty cycle  in cpufreq_p4_setdc()
81 		l = l | (1<<4) | ((newstate & 0x7)<<1);  in cpufreq_p4_setdc()
82 		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);  in cpufreq_p4_setdc()
107 	/* run on each logical CPU,  in cpufreq_p4_target()
111 	for_each_cpu(i, policy->cpus)  in cpufreq_p4_target()
120 	if (c->x86 == 0x06) {  in cpufreq_p4_get_frequency()
122 …ng: EST-capable CPU detected. The acpi-cpufreq module offers voltage scaling in addition to freque…  in cpufreq_p4_get_frequency()
123 		switch (c->x86_model) {  in cpufreq_p4_get_frequency()
138 	if (c->x86 != 0xF)  in cpufreq_p4_get_frequency()
141 	/* on P-4s, the TSC runs with constant frequency independent whether  in cpufreq_p4_get_frequency()
146 …4-M detected. The speedstep-ich or acpi cpufreq modules offer voltage scaling in addition of frequ…  in cpufreq_p4_get_frequency()
157 	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);  in cpufreq_p4_cpu_init()
162 	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));  in cpufreq_p4_cpu_init()
166 	cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_stepping;  in cpufreq_p4_cpu_init()
172 		has_N44_O17_errata[policy->cpu] = 1;  in cpufreq_p4_cpu_init()
173 		pr_debug("has errata -- disabling low frequencies\n");  in cpufreq_p4_cpu_init()
177 	    c->x86_model < 2) {  in cpufreq_p4_cpu_init()
179 		cpufreq_p4_setdc(policy->cpu, DC_DISABLE);  in cpufreq_p4_cpu_init()
185 		return -EINVAL;  in cpufreq_p4_cpu_init()
189 		if ((i < 2) && (has_N44_O17_errata[policy->cpu]))  in cpufreq_p4_cpu_init()
199 	policy->cpuinfo.transition_latency = 10000001;  in cpufreq_p4_cpu_init()
200 	policy->freq_table = &p4clockmod_table[0];  in cpufreq_p4_cpu_init()
206 static unsigned int cpufreq_p4_get(unsigned int cpu)  in cpufreq_p4_get()  argument
210 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);  in cpufreq_p4_get()
229 	.name		= "p4-clockmod",
252 		return -ENODEV;  in cpufreq_p4_init()
256 		pr_info("P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");  in cpufreq_p4_init()
269 MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");