root/drivers/powercap/intel_rapl_msr.c

DEFINITIONS

1. rapl_cpu_online
2. rapl_cpu_down_prep
3. rapl_msr_read_raw
4. rapl_msr_update_func
5. rapl_msr_write_raw
6. rapl_msr_probe
7. rapl_msr_remove

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel Running Average Power Limit (RAPL) Driver via MSR interface
   4  * Copyright (c) 2019, Intel Corporation.
   5  */
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7 
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/list.h>
  11 #include <linux/types.h>
  12 #include <linux/device.h>
  13 #include <linux/slab.h>
  14 #include <linux/log2.h>
  15 #include <linux/bitmap.h>
  16 #include <linux/delay.h>
  17 #include <linux/sysfs.h>
  18 #include <linux/cpu.h>
  19 #include <linux/powercap.h>
  20 #include <linux/suspend.h>
  21 #include <linux/intel_rapl.h>
  22 #include <linux/processor.h>
  23 #include <linux/platform_device.h>
  24 
  25 #include <asm/iosf_mbi.h>
  26 #include <asm/cpu_device_id.h>
  27 #include <asm/intel-family.h>
  28 
  29 /* Local defines */
  30 #define MSR_PLATFORM_POWER_LIMIT        0x0000065C
  31 
  32 /* private data for RAPL MSR Interface */
  33 static struct rapl_if_priv rapl_msr_priv = {
  34         .reg_unit = MSR_RAPL_POWER_UNIT,
  35         .regs[RAPL_DOMAIN_PACKAGE] = {
  36                 MSR_PKG_POWER_LIMIT, MSR_PKG_ENERGY_STATUS, MSR_PKG_PERF_STATUS, 0, MSR_PKG_POWER_INFO },
  37         .regs[RAPL_DOMAIN_PP0] = {
  38                 MSR_PP0_POWER_LIMIT, MSR_PP0_ENERGY_STATUS, 0, MSR_PP0_POLICY, 0 },
  39         .regs[RAPL_DOMAIN_PP1] = {
  40                 MSR_PP1_POWER_LIMIT, MSR_PP1_ENERGY_STATUS, 0, MSR_PP1_POLICY, 0 },
  41         .regs[RAPL_DOMAIN_DRAM] = {
  42                 MSR_DRAM_POWER_LIMIT, MSR_DRAM_ENERGY_STATUS, MSR_DRAM_PERF_STATUS, 0, MSR_DRAM_POWER_INFO },
  43         .regs[RAPL_DOMAIN_PLATFORM] = {
  44                 MSR_PLATFORM_POWER_LIMIT, MSR_PLATFORM_ENERGY_STATUS, 0, 0, 0},
  45         .limits[RAPL_DOMAIN_PACKAGE] = 2,
  46 };
  47 
  48 /* Handles CPU hotplug on multi-socket systems.
  49  * If a CPU goes online as the first CPU of the physical package
  50  * we add the RAPL package to the system. Similarly, when the last
  51  * CPU of the package is removed, we remove the RAPL package and its
  52  * associated domains. Cooling devices are handled accordingly at
  53  * per-domain level.
  54  */
  55 static int rapl_cpu_online(unsigned int cpu)
  56 {
  57         struct rapl_package *rp;
  58 
  59         rp = rapl_find_package_domain(cpu, &rapl_msr_priv);
  60         if (!rp) {
  61                 rp = rapl_add_package(cpu, &rapl_msr_priv);
  62                 if (IS_ERR(rp))
  63                         return PTR_ERR(rp);
  64         }
  65         cpumask_set_cpu(cpu, &rp->cpumask);
  66         return 0;
  67 }
  68 
  69 static int rapl_cpu_down_prep(unsigned int cpu)
  70 {
  71         struct rapl_package *rp;
  72         int lead_cpu;
  73 
  74         rp = rapl_find_package_domain(cpu, &rapl_msr_priv);
  75         if (!rp)
  76                 return 0;
  77 
  78         cpumask_clear_cpu(cpu, &rp->cpumask);
  79         lead_cpu = cpumask_first(&rp->cpumask);
  80         if (lead_cpu >= nr_cpu_ids)
  81                 rapl_remove_package(rp);
  82         else if (rp->lead_cpu == cpu)
  83                 rp->lead_cpu = lead_cpu;
  84         return 0;
  85 }
  86 
  87 static int rapl_msr_read_raw(int cpu, struct reg_action *ra)
  88 {
  89         u32 msr = (u32)ra->reg;
  90 
  91         if (rdmsrl_safe_on_cpu(cpu, msr, &ra->value)) {
  92                 pr_debug("failed to read msr 0x%x on cpu %d\n", msr, cpu);
  93                 return -EIO;
  94         }
  95         ra->value &= ra->mask;
  96         return 0;
  97 }
  98 
  99 static void rapl_msr_update_func(void *info)
 100 {
 101         struct reg_action *ra = info;
 102         u32 msr = (u32)ra->reg;
 103         u64 val;
 104 
 105         ra->err = rdmsrl_safe(msr, &val);
 106         if (ra->err)
 107                 return;
 108 
 109         val &= ~ra->mask;
 110         val |= ra->value;
 111 
 112         ra->err = wrmsrl_safe(msr, val);
 113 }
 114 
 115 static int rapl_msr_write_raw(int cpu, struct reg_action *ra)
 116 {
 117         int ret;
 118 
 119         ret = smp_call_function_single(cpu, rapl_msr_update_func, ra, 1);
 120         if (WARN_ON_ONCE(ret))
 121                 return ret;
 122 
 123         return ra->err;
 124 }
 125 
 126 static int rapl_msr_probe(struct platform_device *pdev)
 127 {
 128         int ret;
 129 
 130         rapl_msr_priv.read_raw = rapl_msr_read_raw;
 131         rapl_msr_priv.write_raw = rapl_msr_write_raw;
 132 
 133         rapl_msr_priv.control_type = powercap_register_control_type(NULL, "intel-rapl", NULL);
 134         if (IS_ERR(rapl_msr_priv.control_type)) {
 135                 pr_debug("failed to register powercap control_type.\n");
 136                 return PTR_ERR(rapl_msr_priv.control_type);
 137         }
 138 
 139         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powercap/rapl:online",
 140                                 rapl_cpu_online, rapl_cpu_down_prep);
 141         if (ret < 0)
 142                 goto out;
 143         rapl_msr_priv.pcap_rapl_online = ret;
 144 
 145         /* Don't bail out if PSys is not supported */
 146         rapl_add_platform_domain(&rapl_msr_priv);
 147 
 148         return 0;
 149 
 150 out:
 151         if (ret)
 152                 powercap_unregister_control_type(rapl_msr_priv.control_type);
 153         return ret;
 154 }
 155 
 156 static int rapl_msr_remove(struct platform_device *pdev)
 157 {
 158         cpuhp_remove_state(rapl_msr_priv.pcap_rapl_online);
 159         rapl_remove_platform_domain(&rapl_msr_priv);
 160         powercap_unregister_control_type(rapl_msr_priv.control_type);
 161         return 0;
 162 }
 163 
 164 static const struct platform_device_id rapl_msr_ids[] = {
 165         { .name = "intel_rapl_msr", },
 166         {}
 167 };
 168 MODULE_DEVICE_TABLE(platform, rapl_msr_ids);
 169 
 170 static struct platform_driver intel_rapl_msr_driver = {
 171         .probe = rapl_msr_probe,
 172         .remove = rapl_msr_remove,
 173         .id_table = rapl_msr_ids,
 174         .driver = {
 175                 .name = "intel_rapl_msr",
 176         },
 177 };
 178 
 179 module_platform_driver(intel_rapl_msr_driver);
 180 
 181 MODULE_DESCRIPTION("Driver for Intel RAPL (Running Average Power Limit) control via MSR interface");
 182 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
 183 MODULE_LICENSE("GPL v2");