Commit 658fa7b1 authored by Sumit Gupta's avatar Sumit Gupta Committed by Rafael J. Wysocki
Browse files

ACPI: CPPC: Add cppc_get_perf() API to read performance controls 



Add cppc_get_perf() function to read values of performance control
registers including desired_perf, min_perf, max_perf, energy_perf,
and auto_sel.

This provides a read interface to complement the existing
cppc_set_perf() write interface for performance control registers.

Note that auto_sel is read by cppc_get_perf() but not written by
cppc_set_perf() to avoid unintended mode changes during performance
updates. It can be updated with existing dedicated cppc_set_auto_sel()
API.

Use cppc_get_perf() in cppc_cpufreq_get_cpu_data() to initialize
perf_ctrls with current hardware register values during cpufreq
policy initialization.

Signed-off-by: default avatarSumit Gupta <sumitg@nvidia.com>
Reviewed-by: default avatarPierre Gondois <pierre.gondois@arm.com>
Reviewed-by: default avatarLifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20260206142658.72583-2-sumitg@nvidia.com


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6de23f81

drivers/acpi/cppc_acpi.c

+80 −0
Original line number Diff line number Diff line
@@ -1738,6 +1738,86 @@ int cppc_set_enable(int cpu, bool enable) 
}

EXPORT_SYMBOL_GPL(cppc_set_enable);



/**

 * cppc_get_perf - Get a CPU's performance controls.

 * @cpu: CPU for which to get performance controls.

 * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h

 *

 * Return: 0 for success with perf_ctrls, -ERRNO otherwise.

 */

int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)

{

	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);

	struct cpc_register_resource *desired_perf_reg,

				     *min_perf_reg, *max_perf_reg,

				     *energy_perf_reg, *auto_sel_reg;

	u64 desired_perf = 0, min = 0, max = 0, energy_perf = 0, auto_sel = 0;

	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);

	struct cppc_pcc_data *pcc_ss_data = NULL;

	int ret = 0, regs_in_pcc = 0;



	if (!cpc_desc) {

		pr_debug("No CPC descriptor for CPU:%d\n", cpu);

		return -ENODEV;

	}



	if (!perf_ctrls) {

		pr_debug("Invalid perf_ctrls pointer\n");

		return -EINVAL;

	}



	desired_perf_reg = &cpc_desc->cpc_regs[DESIRED_PERF];

	min_perf_reg = &cpc_desc->cpc_regs[MIN_PERF];

	max_perf_reg = &cpc_desc->cpc_regs[MAX_PERF];

	energy_perf_reg = &cpc_desc->cpc_regs[ENERGY_PERF];

	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];



	/* Are any of the regs PCC ?*/

	if (CPC_IN_PCC(desired_perf_reg) || CPC_IN_PCC(min_perf_reg) ||

	    CPC_IN_PCC(max_perf_reg) || CPC_IN_PCC(energy_perf_reg) ||

	    CPC_IN_PCC(auto_sel_reg)) {

		if (pcc_ss_id < 0) {

			pr_debug("Invalid pcc_ss_id for CPU:%d\n", cpu);

			return -ENODEV;

		}

		pcc_ss_data = pcc_data[pcc_ss_id];

		regs_in_pcc = 1;

		down_write(&pcc_ss_data->pcc_lock);

		/* Ring doorbell once to update PCC subspace */

		if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {

			ret = -EIO;

			goto out_err;

		}

	}



	/* Read optional elements if present */

	if (CPC_SUPPORTED(max_perf_reg))

		cpc_read(cpu, max_perf_reg, &max);

	perf_ctrls->max_perf = max;



	if (CPC_SUPPORTED(min_perf_reg))

		cpc_read(cpu, min_perf_reg, &min);

	perf_ctrls->min_perf = min;



	if (CPC_SUPPORTED(desired_perf_reg))

		cpc_read(cpu, desired_perf_reg, &desired_perf);

	perf_ctrls->desired_perf = desired_perf;



	if (CPC_SUPPORTED(energy_perf_reg))

		cpc_read(cpu, energy_perf_reg, &energy_perf);

	perf_ctrls->energy_perf = energy_perf;



	if (CPC_SUPPORTED(auto_sel_reg))

		cpc_read(cpu, auto_sel_reg, &auto_sel);

	perf_ctrls->auto_sel = (bool)auto_sel;



out_err:

	if (regs_in_pcc)

		up_write(&pcc_ss_data->pcc_lock);

	return ret;

}

EXPORT_SYMBOL_GPL(cppc_get_perf);



/**

 * cppc_set_perf - Set a CPU's performance controls.

 * @cpu: CPU for which to set performance controls.

drivers/cpufreq/cppc_cpufreq.c

+6 −0
Original line number Diff line number Diff line
@@ -594,6 +594,12 @@ static struct cppc_cpudata *cppc_cpufreq_get_cpu_data(unsigned int cpu) 
		goto free_mask;

	}



	ret = cppc_get_perf(cpu, &cpu_data->perf_ctrls);

	if (ret) {

		pr_debug("Err reading CPU%d perf ctrls: ret:%d\n", cpu, ret);

		goto free_mask;

	}



	return cpu_data;



free_mask:

include/acpi/cppc_acpi.h

+5 −0
Original line number Diff line number Diff line
@@ -151,6 +151,7 @@ extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf); 
extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);

extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);

extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);

extern int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);

extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);

extern int cppc_set_enable(int cpu, bool enable);

extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
@@ -193,6 +194,10 @@ static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ 
{

	return -EOPNOTSUPP;

}

static inline int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)

{

	return -EOPNOTSUPP;

}

static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)

{

	return -EOPNOTSUPP;