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_ffh_supported(void) 15 { 16 return true; 17 } 18 19 int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val) 20 { 21 int err; 22 23 err = rdmsrl_safe_on_cpu(cpunum, reg->address, val); 24 if (!err) { 25 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, 26 reg->bit_offset); 27 28 *val &= mask; 29 *val >>= reg->bit_offset; 30 } 31 return err; 32 } 33 34 int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) 35 { 36 u64 rd_val; 37 int err; 38 39 err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val); 40 if (!err) { 41 u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, 42 reg->bit_offset); 43 44 val <<= reg->bit_offset; 45 val &= mask; 46 rd_val &= ~mask; 47 rd_val |= val; 48 err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val); 49 } 50 return err; 51 } 52 53 static void amd_set_max_freq_ratio(void) 54 { 55 struct cppc_perf_caps perf_caps; 56 u64 highest_perf, nominal_perf; 57 u64 perf_ratio; 58 int rc; 59 60 rc = cppc_get_perf_caps(0, &perf_caps); 61 if (rc) { 62 pr_debug("Could not retrieve perf counters (%d)\n", rc); 63 return; 64 } 65 66 highest_perf = amd_get_highest_perf(); 67 nominal_perf = perf_caps.nominal_perf; 68 69 if (!highest_perf || !nominal_perf) { 70 pr_debug("Could not retrieve highest or nominal performance\n"); 71 return; 72 } 73 74 perf_ratio = div_u64(highest_perf * SCHED_CAPACITY_SCALE, nominal_perf); 75 /* midpoint between max_boost and max_P */ 76 perf_ratio = (perf_ratio + SCHED_CAPACITY_SCALE) >> 1; 77 if (!perf_ratio) { 78 pr_debug("Non-zero highest/nominal perf values led to a 0 ratio\n"); 79 return; 80 } 81 82 freq_invariance_set_perf_ratio(perf_ratio, false); 83 } 84 85 static DEFINE_MUTEX(freq_invariance_lock); 86 87 void init_freq_invariance_cppc(void) 88 { 89 static bool init_done; 90 91 if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF)) 92 return; 93 94 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) 95 return; 96 97 mutex_lock(&freq_invariance_lock); 98 if (!init_done) 99 amd_set_max_freq_ratio(); 100 init_done = true; 101 mutex_unlock(&freq_invariance_lock); 102 } 103