Re: [PATCH v2 2/6] acpi: cppc: Add auto select register read/write support

Mario Limonciello
2023-01-13T05:55:39Z

On 1/12/23 23:21, Wyes Karny wrote:
> For some shared memory based systems, the autonomous selection bit

For some "AMD" shared memory systems.

> needed to be set explicitly. Add autonomous selection register related
> APIs to acpi driver, which amd_pstate driver uses later.
>
> Signed-off-by: Wyes Karny <wyes.karny@amd.com>

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
> drivers/acpi/cppc_acpi.c | 97 ++++++++++++++++++++++++++++++++++++++++
> include/acpi/cppc_acpi.h | 11 +++++
> 2 files changed, 108 insertions(+)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index c936ff503965..e47b2cfe022e 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1432,6 +1432,103 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> }
> EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
>
> +/*
> + * cppc_get_auto_sel_caps - Read autonomous selection register.
> + * @cpunum : CPU from which to read register.
> + * @perf_caps : struct where autonomous selection register value is updated.
> + */
> +int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps)
> +{
> + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
> + struct cpc_register_resource *auto_sel_reg;
> + u64 auto_sel;
> +
> + if (!cpc_desc) {
> + pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
> + return -ENODEV;
> + }
> +
> + auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
> +
> + if (!CPC_SUPPORTED(auto_sel_reg))
> + pr_warn_once("Autonomous mode is not unsupported!\n");
> +
> + if (CPC_IN_PCC(auto_sel_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, auto_sel_reg, &auto_sel);
> + perf_caps->auto_sel = (bool)auto_sel;
> + } else {
> + ret = -EIO;
> + }
> +
> + up_write(&pcc_ss_data->pcc_lock);
> +
> + return ret;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_auto_sel_caps);
> +
> +/*
> + * cppc_set_auto_sel - Write autonomous selection register.
> + * @cpunum : CPU to which to write register.
> + * @enable : the desired value of autonomous selection resiter to be updated.
> + */
> +int cppc_set_auto_sel(int cpu, bool enable)
> +{
> + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
> + 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];
> +
> + if (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;
> + }
> +
> + 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_auto_sel);
> +
> +
> /**
> * 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 6b487a5bd638..6126c977ece0 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -109,6 +109,7 @@ struct cppc_perf_caps {
> u32 lowest_freq;
> u32 nominal_freq;
> u32 energy_perf;
> + bool auto_sel;
> };
>
> struct cppc_perf_ctrls {
> @@ -153,6 +154,8 @@ 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_perf(int cpunum, u64 *epp_perf);
> extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
> +extern int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps);
> +extern int cppc_set_auto_sel(int cpu, bool enable);
> #else /* !CONFIG_ACPI_CPPC_LIB */
> static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
> {
> @@ -214,6 +217,14 @@ static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
> {
> return -ENOTSUPP;
> }
> +static inline int cppc_set_auto_sel(int cpu, bool enable)
> +{
> + return -ENOTSUPP;
> +}
> +static inline int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps)
> +{
> + return -ENOTSUPP;
> +}
> #endif /* !CONFIG_ACPI_CPPC_LIB */
>
> #endif /* _CPPC_ACPI_H*/