diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index b32f13358fbb..d28438f8b83f 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -373,6 +373,16 @@ core_initcall(init_amu_fie); #ifdef CONFIG_ACPI_CPPC_LIB #include +struct amu_ffh_ctrs { + u64 corecnt; + u64 constcnt; +}; + +enum cpc_ffh_ctr_id { + CPC_FFH_CTR_CORE = 0x0, + CPC_FFH_CTR_CONST = 0x1, +}; + static void cpu_read_corecnt(void *val) { /* @@ -397,7 +407,7 @@ static void cpu_read_constcnt(void *val) } static inline -int counters_read_on_cpu(int cpu, smp_call_func_t func, u64 *val) +int counters_read_on_cpu(int cpu, smp_call_func_t func, void *val) { /* * Abort call on counterless CPU. @@ -447,24 +457,90 @@ bool cpc_ffh_supported(void) return true; } +static void amu_read_core_const_ctrs(void *val) +{ + struct amu_ffh_ctrs *ctrs = val; + + /* + * cpu_read_constcnt() incurs slight latency due to the + * ARM64_WORKAROUND_2457168 check. Read it first to minimize + * the sampling skew between the const and core counters. + */ + cpu_read_constcnt(&ctrs->constcnt); + cpu_read_corecnt(&ctrs->corecnt); +} + +static u64 cpc_ffh_extract_bits(const struct cpc_reg *reg, u64 val) +{ + val &= GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, + reg->bit_offset); + val >>= reg->bit_offset; + + return val; +} + +static void cpc_ffh_ctr_value(const struct cpc_reg *reg, + const struct amu_ffh_ctrs *ctrs, u64 *val) +{ + switch ((u64)reg->address) { + case CPC_FFH_CTR_CORE: + *val = ctrs->corecnt; + break; + case CPC_FFH_CTR_CONST: + *val = ctrs->constcnt; + break; + } + + *val = cpc_ffh_extract_bits(reg, *val); +} + +static bool is_amu_ctr_reg(const struct cpc_reg *reg) +{ + return reg->address == CPC_FFH_CTR_CORE || + reg->address == CPC_FFH_CTR_CONST; +} + +int cpc_read_ffh_fb_ctrs(int cpu, struct cpc_reg *reg1, u64 *val1, + struct cpc_reg *reg2, u64 *val2) +{ + struct amu_ffh_ctrs ctrs; + int ret; + + if (!is_amu_ctr_reg(reg1) || !is_amu_ctr_reg(reg2)) + return -EINVAL; + + ret = counters_read_on_cpu(cpu, amu_read_core_const_ctrs, &ctrs); + if (ret) { + /* + * If AMU is unsupported (-EOPNOTSUPP), translate the error + * to -ENODEV. This explicitly tells the generic CPPC layer + * to abort immediately and avoid falling back to pointless + * single-counter reads. + */ + return ret == -EOPNOTSUPP ? -ENODEV : ret; + } + + cpc_ffh_ctr_value(reg1, &ctrs, val1); + cpc_ffh_ctr_value(reg2, &ctrs, val2); + + return 0; +} + int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val) { int ret = -EOPNOTSUPP; switch ((u64)reg->address) { - case 0x0: + case CPC_FFH_CTR_CORE: ret = counters_read_on_cpu(cpu, cpu_read_corecnt, val); break; - case 0x1: + case CPC_FFH_CTR_CONST: ret = counters_read_on_cpu(cpu, cpu_read_constcnt, val); break; } - if (!ret) { - *val &= GENMASK_ULL(reg->bit_offset + reg->bit_width - 1, - reg->bit_offset); - *val >>= reg->bit_offset; - } + if (!ret) + *val = cpc_ffh_extract_bits(reg, *val); return ret; } diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 9f572f481241..b6356476a46e 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1004,6 +1004,22 @@ int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val) return -ENOTSUPP; } +/** + * cpc_read_ffh_fb_ctrs() - Read FFH feedback counters together + * @cpunum: Target CPU + * @reg1: first CPPC register information + * @val1: place holder for first return value + * @reg2: second CPPC register information + * @val2: place holder for second return value + * + * Return: 0 on success, error code otherwise + */ +int __weak cpc_read_ffh_fb_ctrs(int cpunum, struct cpc_reg *reg1, + u64 *val1, struct cpc_reg *reg2, u64 *val2) +{ + return -EOPNOTSUPP; +} + /** * cpc_write_ffh() - Write FFH register * @cpunum: CPU number to write @@ -1496,6 +1512,33 @@ bool cppc_perf_ctrs_in_pcc_cpu(unsigned int cpu) } EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc_cpu); +static int cppc_read_fb_ctrs(int cpunum, + struct cpc_register_resource *delivered_reg, + struct cpc_register_resource *reference_reg, + u64 *delivered, u64 *reference) +{ + int ret; + + /* + * For FFH feedback counters, try a paired read first to reduce + * sampling skew between delivered and reference counters. Fall + * back to the existing per-register reads if unsupported. + */ + if (CPC_IN_FFH(delivered_reg) && CPC_IN_FFH(reference_reg)) { + ret = cpc_read_ffh_fb_ctrs(cpunum, + &delivered_reg->cpc_entry.reg, delivered, + &reference_reg->cpc_entry.reg, reference); + if (ret != -EOPNOTSUPP) + return ret; + } + + ret = cpc_read(cpunum, delivered_reg, delivered); + if (ret) + return ret; + + return cpc_read(cpunum, reference_reg, reference); +} + /** * cppc_perf_ctrs_in_pcc - Check if any perf counters are in a PCC region. * @@ -1561,11 +1604,8 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs) } } - ret = cpc_read(cpunum, delivered_reg, &delivered); - if (ret) - goto out_err; - - ret = cpc_read(cpunum, reference_reg, &reference); + ret = cppc_read_fb_ctrs(cpunum, delivered_reg, reference_reg, + &delivered, &reference); if (ret) goto out_err; diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h index 8693890a7275..5acebe62feac 100644 --- a/include/acpi/cppc_acpi.h +++ b/include/acpi/cppc_acpi.h @@ -176,6 +176,8 @@ extern int cppc_get_transition_latency(int cpu); extern bool cpc_ffh_supported(void); extern bool cpc_supported_by_cpu(void); extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val); +extern int cpc_read_ffh_fb_ctrs(int cpu, struct cpc_reg *reg1, u64 *val1, + struct cpc_reg *reg2, u64 *val2); extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val); extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf); extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable); @@ -250,6 +252,11 @@ static inline int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val) { return -EOPNOTSUPP; } +static inline int cpc_read_ffh_fb_ctrs(int cpu, struct cpc_reg *reg1, u64 *val1, + struct cpc_reg *reg2, u64 *val2) +{ + return -EOPNOTSUPP; +} static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) { return -EOPNOTSUPP;