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    Subject[PATCH v4 1/9] ACPI: CPPC: Add AMD pstate energy performance preference cppc control
    Date
    Add support for setting and querying EPP preferences to the generic
    CPPC driver. This enables downstream drivers such as amd-pstate to discover
    and use these values

    In order to get EPP worked, cppc_get_epp_caps() will query EPP preference
    value and cppc_set_epp_perf() will set EPP new value.
    Before the EPP works, pstate driver will use cppc_set_auto_epp() to
    enable EPP function from firmware firstly.

    Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
    ---
    drivers/acpi/cppc_acpi.c | 114 +++++++++++++++++++++++++++++++++++++--
    include/acpi/cppc_acpi.h | 12 +++++
    2 files changed, 121 insertions(+), 5 deletions(-)

    diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
    index 093675b1a1ff..37fa75f25f62 100644
    --- a/drivers/acpi/cppc_acpi.c
    +++ b/drivers/acpi/cppc_acpi.c
    @@ -1093,6 +1093,9 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
    {
    struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
    struct cpc_register_resource *reg;
    + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
    + struct cppc_pcc_data *pcc_ss_data = NULL;
    + int ret = -EINVAL;

    if (!cpc_desc) {
    pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
    @@ -1102,10 +1105,6 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
    reg = &cpc_desc->cpc_regs[reg_idx];

    if (CPC_IN_PCC(reg)) {
    - int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
    - struct cppc_pcc_data *pcc_ss_data = NULL;
    - int ret = 0;
    -
    if (pcc_ss_id < 0)
    return -EIO;

    @@ -1125,7 +1124,7 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)

    cpc_read(cpunum, reg, perf);

    - return 0;
    + return ret;
    }

    /**
    @@ -1365,6 +1364,111 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
    }
    EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);

    +/**
    + * cppc_get_epp_caps - Get the energy preference register value.
    + * @cpunum: CPU from which to get epp preference level.
    + * @perf_caps: Return address.
    + *
    + * Return: 0 for success, -EIO otherwise.
    + */
    +int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps)
    +{
    + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
    + struct cpc_register_resource *energy_perf_reg;
    + u64 energy_perf;
    +
    + if (!cpc_desc) {
    + pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
    + return -ENODEV;
    + }
    +
    + energy_perf_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
    +
    + if (!CPC_SUPPORTED(energy_perf_reg))
    + pr_warn_once("energy perf reg update is unsupported!\n");
    +
    + if (CPC_IN_PCC(energy_perf_reg)) {
    + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
    + struct cppc_pcc_data *pcc_ss_data = NULL;
    + int ret = 0;
    +
    + if (pcc_ss_id < 0)
    + return -ENODEV;
    +
    + pcc_ss_data = pcc_data[pcc_ss_id];
    +
    + down_write(&pcc_ss_data->pcc_lock);
    +
    + if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0) {
    + cpc_read(cpunum, energy_perf_reg, &energy_perf);
    + perf_caps->energy_perf = energy_perf;
    + } else {
    + ret = -EIO;
    + }
    +
    + up_write(&pcc_ss_data->pcc_lock);
    +
    + return ret;
    + }
    +
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(cppc_get_epp_caps);
    +
    +/*
    + * Set Energy Performance Preference Register value through
    + * Performance Controls Interface
    + */
    +int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
    +{
    + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
    + struct cpc_register_resource *epp_set_reg;
    + struct cpc_register_resource *auto_sel_reg;
    + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
    + struct cppc_pcc_data *pcc_ss_data = NULL;
    + int ret = -EINVAL;
    +
    + if (!cpc_desc) {
    + pr_debug("No CPC descriptor for CPU:%d\n", cpu);
    + return -ENODEV;
    + }
    +
    + auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
    + epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
    +
    + if (CPC_IN_PCC(epp_set_reg) || CPC_IN_PCC(auto_sel_reg)) {
    + if (pcc_ss_id < 0) {
    + pr_debug("Invalid pcc_ss_id\n");
    + return -ENODEV;
    + }
    +
    + if (CPC_SUPPORTED(auto_sel_reg)) {
    + ret = cpc_write(cpu, auto_sel_reg, enable);
    + if (ret)
    + return ret;
    + }
    +
    + if (CPC_SUPPORTED(epp_set_reg)) {
    + ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf);
    + if (ret)
    + return ret;
    + }
    +
    + pcc_ss_data = pcc_data[pcc_ss_id];
    +
    + down_write(&pcc_ss_data->pcc_lock);
    + /* after writing CPC, transfer the ownership of PCC to platform */
    + ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
    + up_write(&pcc_ss_data->pcc_lock);
    + } else {
    + ret = -ENOTSUPP;
    + pr_debug("_CPC in PCC is not supported\n");
    + }
    +
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
    +
    /**
    * cppc_set_enable - Set to enable CPPC on the processor by writing the
    * Continuous Performance Control package EnableRegister field.
    diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
    index c5614444031f..a93393b05171 100644
    --- a/include/acpi/cppc_acpi.h
    +++ b/include/acpi/cppc_acpi.h
    @@ -108,12 +108,14 @@ struct cppc_perf_caps {
    u32 lowest_nonlinear_perf;
    u32 lowest_freq;
    u32 nominal_freq;
    + u32 energy_perf;
    };

    struct cppc_perf_ctrls {
    u32 max_perf;
    u32 min_perf;
    u32 desired_perf;
    + u32 energy_perf;
    };

    struct cppc_perf_fb_ctrs {
    @@ -149,6 +151,8 @@ 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_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
    +extern int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps);
    +extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
    #else /* !CONFIG_ACPI_CPPC_LIB */
    static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
    {
    @@ -202,6 +206,14 @@ static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
    {
    return -ENOTSUPP;
    }
    +static inline int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, boot enable)
    +{
    + return -ENOTSUPP;
    +}
    +static inline int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps)
    +{
    + return -ENOTSUPP;
    +}
    #endif /* !CONFIG_ACPI_CPPC_LIB */

    #endif /* _CPPC_ACPI_H*/
    --
    2.34.1
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