cpufreq: Add SFI based cpufreq driver support (e7ddf4b7) · Commits · 戴 / test

arch/x86/include/uapi/asm/msr-index.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -318,6 +318,7 @@

		#define MSR_IA32_PERF_STATUS 0x00000198
		#define MSR_IA32_PERF_CTL 0x00000199
		#define INTEL_PERF_CTL_MASK 0xffff
		#define MSR_AMD_PSTATE_DEF_BASE 0xc0010064
		#define MSR_AMD_PERF_STATUS 0xc0010063
		#define MSR_AMD_PERF_CTL 0xc0010062

drivers/cpufreq/Kconfig.x86

+10 −0

Original line number	Diff line number	Diff line
		@@ -57,6 +57,16 @@ config X86_ACPI_CPUFREQ_CPB
		By enabling this option the acpi_cpufreq driver provides the old
		entry in addition to the new boost ones, for compatibility reasons.

		config X86_SFI_CPUFREQ
		tristate "SFI Performance-States driver"
		depends on X86_INTEL_MID && SFI
		help
		This adds a CPUFreq driver for some Silvermont based Intel Atom
		architectures like Z34xx and Z35xx which enumerate processor
		performance states through SFI.

		If in doubt, say N.

		config ELAN_CPUFREQ
		tristate "AMD Elan SC400 and SC410"
		depends on MELAN

drivers/cpufreq/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,7 @@ obj-$(CONFIG_X86_P4_CLOCKMOD) += p4-clockmod.o
		obj-$(CONFIG_X86_CPUFREQ_NFORCE2) += cpufreq-nforce2.o
		obj-$(CONFIG_X86_INTEL_PSTATE) += intel_pstate.o
		obj-$(CONFIG_X86_AMD_FREQ_SENSITIVITY) += amd_freq_sensitivity.o
		obj-$(CONFIG_X86_SFI_CPUFREQ) += sfi-cpufreq.o

		##################################################################################
		# ARM SoC drivers

drivers/cpufreq/sfi-cpufreq.c

0 → 100644

+136 −0

Original line number	Diff line number	Diff line
		/*
		* SFI Performance States Driver
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License.
		*
		* This program is distributed in the hope that it will be useful, but
		* WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
		* General Public License for more details.
		*
		* Author: Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>
		* Author: Srinidhi Kasagar <srinidhi.kasagar@intel.com>
		*/

		#include <linux/cpufreq.h>
		#include <linux/init.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/sfi.h>
		#include <linux/slab.h>
		#include <linux/smp.h>

		#include <asm/msr.h>

		struct cpufreq_frequency_table *freq_table;
		static struct sfi_freq_table_entry *sfi_cpufreq_array;
		static int num_freq_table_entries;

		static int sfi_parse_freq(struct sfi_table_header *table)
		{
		struct sfi_table_simple *sb;
		struct sfi_freq_table_entry *pentry;
		int totallen;

		sb = (struct sfi_table_simple *)table;
		num_freq_table_entries = SFI_GET_NUM_ENTRIES(sb,
		struct sfi_freq_table_entry);
		if (num_freq_table_entries <= 1) {
		pr_err("No p-states discovered\n");
		return -ENODEV;
		}

		pentry = (struct sfi_freq_table_entry *)sb->pentry;
		totallen = num_freq_table_entries * sizeof(*pentry);

		sfi_cpufreq_array = kzalloc(totallen, GFP_KERNEL);
		if (!sfi_cpufreq_array)
		return -ENOMEM;

		memcpy(sfi_cpufreq_array, pentry, totallen);

		return 0;
		}

		static int sfi_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
		{
		unsigned int next_perf_state = 0; /* Index into perf table */
		u32 lo, hi;

		next_perf_state = policy->freq_table[index].driver_data;

		rdmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, &lo, &hi);
		lo = (lo & ~INTEL_PERF_CTL_MASK) \|
		((u32) sfi_cpufreq_array[next_perf_state].ctrl_val &
		INTEL_PERF_CTL_MASK);
		wrmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, lo, hi);

		return 0;
		}

		static int sfi_cpufreq_cpu_init(struct cpufreq_policy *policy)
		{
		policy->shared_type = CPUFREQ_SHARED_TYPE_HW;
		policy->cpuinfo.transition_latency = 100000; /* 100us */

		return cpufreq_table_validate_and_show(policy, freq_table);
		}

		static struct cpufreq_driver sfi_cpufreq_driver = {
		.flags = CPUFREQ_CONST_LOOPS,
		.verify = cpufreq_generic_frequency_table_verify,
		.target_index = sfi_cpufreq_target,
		.init = sfi_cpufreq_cpu_init,
		.name = "sfi-cpufreq",
		.attr = cpufreq_generic_attr,
		};

		static int __init sfi_cpufreq_init(void)
		{
		int ret, i;

		/* parse the freq table from SFI */
		ret = sfi_table_parse(SFI_SIG_FREQ, NULL, NULL, sfi_parse_freq);
		if (ret)
		return ret;

		freq_table = kzalloc(sizeof(freq_table)
		(num_freq_table_entries + 1), GFP_KERNEL);
		if (!freq_table) {
		ret = -ENOMEM;
		goto err_free_array;
		}

		for (i = 0; i < num_freq_table_entries; i++) {
		freq_table[i].driver_data = i;
		freq_table[i].frequency = sfi_cpufreq_array[i].freq_mhz * 1000;
		}
		freq_table[i].frequency = CPUFREQ_TABLE_END;

		ret = cpufreq_register_driver(&sfi_cpufreq_driver);
		if (ret)
		goto err_free_tbl;

		return ret;

		err_free_tbl:
		kfree(freq_table);
		err_free_array:
		kfree(sfi_cpufreq_array);
		return ret;
		}
		late_initcall(sfi_cpufreq_init);

		static void __exit sfi_cpufreq_exit(void)
		{
		cpufreq_unregister_driver(&sfi_cpufreq_driver);
		kfree(freq_table);
		kfree(sfi_cpufreq_array);
		}
		module_exit(sfi_cpufreq_exit);

		MODULE_AUTHOR("Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>");
		MODULE_DESCRIPTION("SFI Performance-States Driver");
		MODULE_LICENSE("GPL");

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