1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * cppc.c: CPPC Interface for x86 4 * Copyright (c) 2016, Intel Corporation. 5 */ 6 7 #include <acpi/cppc_acpi.h> 8 #include <asm/msr.h> 9 #include <asm/processor.h> 10 #include <asm/topology.h> 11 12 /* Refer to drivers/acpi/cppc_acpi.c for the description of functions */ 13 14 bool cpc_supported_by_cpu(void) 15 { 16 switch (boot_cpu_data.x86_vendor) { 17 case X86_VENDOR_AMD: 18 case X86_VENDOR_HYGON: 19 if (boot_cpu_data.x86 == 0x19 && ((boot_cpu_data.x86_model <= 0x0f) || 20 (boot_cpu_data.x86_model >= 0x20 && boot_cpu_data.x86_model <= 0x2f))) 21 return true; 22 else if (boot_cpu_data.x86 == 0x17 && 23 boot_cpu_data.x86_model >= 0x70 && boot_cpu_data.x86_model <= 0x7f) 24 return true; 25 return boot_cpu_has(X86_FEATURE_CPPC); 26 } 27 return false; 28 } 29 30 bool cpc_ffh_supported(void) 31 { 32 return true; 33 } 34 35 int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val) 36 { 37 int err; 38 39 err = rdmsrl_safe_on_cpu(cpunum, reg->address, val); 40 if (!err) { 41 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, 42 reg->bit_offset); 43 44 *val &= mask; 45 *val >>= reg->bit_offset; 46 } 47 return err; 48 } 49 50 int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) 51 { 52 u64 rd_val; 53 int err; 54 55 err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val); 56 if (!err) { 57 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, 58 reg->bit_offset); 59 60 val <<= reg->bit_offset; 61 val &= mask; 62 rd_val &= ~mask; 63 rd_val |= val; 64 err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val); 65 } 66 return err; 67 } 68 69 static void amd_set_max_freq_ratio(void) 70 { 71 struct cppc_perf_caps perf_caps; 72 u64 highest_perf, nominal_perf; 73 u64 perf_ratio; 74 int rc; 75 76 rc = cppc_get_perf_caps(0, &perf_caps); 77 if (rc) { 78 pr_debug("Could not retrieve perf counters (%d)\n", rc); 79 return; 80 } 81 82 highest_perf = amd_get_highest_perf(); 83 nominal_perf = perf_caps.nominal_perf; 84 85 if (!highest_perf || !nominal_perf) { 86 pr_debug("Could not retrieve highest or nominal performance\n"); 87 return; 88 } 89 90 perf_ratio = div_u64(highest_perf * SCHED_CAPACITY_SCALE, nominal_perf); 91 /* midpoint between max_boost and max_P */ 92 perf_ratio = (perf_ratio + SCHED_CAPACITY_SCALE) >> 1; 93 if (!perf_ratio) { 94 pr_debug("Non-zero highest/nominal perf values led to a 0 ratio\n"); 95 return; 96 } 97 98 freq_invariance_set_perf_ratio(perf_ratio, false); 99 } 100 101 static DEFINE_MUTEX(freq_invariance_lock); 102 103 void init_freq_invariance_cppc(void) 104 { 105 static bool init_done; 106 107 if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF)) 108 return; 109 110 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) 111 return; 112 113 mutex_lock(&freq_invariance_lock); 114 if (!init_done) 115 amd_set_max_freq_ratio(); 116 init_done = true; 117 mutex_unlock(&freq_invariance_lock); 118 } 119