diff options
| -rw-r--r-- | arch/x86/include/uapi/asm/msr-index.h | 1 | ||||
| -rw-r--r-- | drivers/cpufreq/Kconfig.x86 | 10 | ||||
| -rw-r--r-- | drivers/cpufreq/Makefile | 1 | ||||
| -rw-r--r-- | drivers/cpufreq/sfi-cpufreq.c | 136 |
4 files changed, 148 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h index e21331ce368f..4f6dae67dd10 100644 --- a/arch/x86/include/uapi/asm/msr-index.h +++ b/arch/x86/include/uapi/asm/msr-index.h @@ -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 diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86 index 89ae88f91895..c59bdcb83217 100644 --- a/drivers/cpufreq/Kconfig.x86 +++ b/drivers/cpufreq/Kconfig.x86 @@ -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 diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 40c53dc1937e..2e50f55e14d3 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -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 diff --git a/drivers/cpufreq/sfi-cpufreq.c b/drivers/cpufreq/sfi-cpufreq.c new file mode 100644 index 000000000000..ffa3389e535b --- /dev/null +++ b/drivers/cpufreq/sfi-cpufreq.c @@ -0,0 +1,136 @@ +/* + * 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"); |