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Commit 256f19d2 authored by Prashanth Prakash's avatar Prashanth Prakash Committed by Rafael J. Wysocki
Browse files

cpufreq / CPPC: Support for CPPC v3 



Use CPPC v3 entries to convert the abstract processor performance to
processor frequency in KHz.

Signed-off-by: default avatarPrashanth Prakash <pprakash@codeaurora.org>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6fa12d58

drivers/cpufreq/cppc_cpufreq.c

+68 −12
Original line number Diff line number Diff line
@@ -42,9 +42,6 @@ 
 */

static struct cppc_cpudata **all_cpu_data;



/* Capture the max KHz from DMI */

static u64 cppc_dmi_max_khz;



/* Callback function used to retrieve the max frequency from DMI */

static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)

{
@@ -75,6 +72,64 @@ static u64 cppc_get_dmi_max_khz(void) 
	return (1000 * mhz);

}



/*

 * If CPPC lowest_freq and nominal_freq registers are exposed then we can

 * use them to convert perf to freq and vice versa

 *

 * If the perf/freq point lies between Nominal and Lowest, we can treat

 * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line

 * and extrapolate the rest

 * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion

 */

static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,

					unsigned int perf)

{

	static u64 max_khz;

	struct cppc_perf_caps *caps = &cpu->perf_caps;

	u64 mul, div;



	if (caps->lowest_freq && caps->nominal_freq) {

		if (perf >= caps->nominal_perf) {

			mul = caps->nominal_freq;

			div = caps->nominal_perf;

		} else {

			mul = caps->nominal_freq - caps->lowest_freq;

			div = caps->nominal_perf - caps->lowest_perf;

		}

	} else {

		if (!max_khz)

			max_khz = cppc_get_dmi_max_khz();

		mul = max_khz;

		div = cpu->perf_caps.highest_perf;

	}

	return (u64)perf * mul / div;

}



static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,

					unsigned int freq)

{

	static u64 max_khz;

	struct cppc_perf_caps *caps = &cpu->perf_caps;

	u64  mul, div;



	if (caps->lowest_freq && caps->nominal_freq) {

		if (freq >= caps->nominal_freq) {

			mul = caps->nominal_perf;

			div = caps->nominal_freq;

		} else {

			mul = caps->lowest_perf;

			div = caps->lowest_freq;

		}

	} else {

		if (!max_khz)

			max_khz = cppc_get_dmi_max_khz();

		mul = cpu->perf_caps.highest_perf;

		div = max_khz;

	}



	return (u64)freq * mul / div;

}



static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,

		unsigned int target_freq,

		unsigned int relation)
@@ -86,7 +141,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, 


	cpu = all_cpu_data[policy->cpu];



	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;

	desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);

	/* Return if it is exactly the same perf */

	if (desired_perf == cpu->perf_ctrls.desired_perf)

		return ret;
@@ -143,24 +198,24 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) 
		return ret;

	}



	cppc_dmi_max_khz = cppc_get_dmi_max_khz();

	/* Convert the lowest and nominal freq from MHz to KHz */

	cpu->perf_caps.lowest_freq *= 1000;

	cpu->perf_caps.nominal_freq *= 1000;



	/*

	 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see

	 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)

	 */

	policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz /

		cpu->perf_caps.highest_perf;

	policy->max = cppc_dmi_max_khz;

	policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);

	policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);



	/*

	 * Set cpuinfo.min_freq to Lowest to make the full range of performance

	 * available if userspace wants to use any perf between lowest & lowest

	 * nonlinear perf

	 */

	policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz /

		cpu->perf_caps.highest_perf;

	policy->cpuinfo.max_freq = cppc_dmi_max_khz;

	policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);

	policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);



	policy->transition_delay_us = cppc_get_transition_latency(cpu_num) /

		NSEC_PER_USEC;
@@ -187,7 +242,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) 
	cpu->cur_policy = policy;



	/* Set policy->cur to max now. The governors will adjust later. */

	policy->cur = cppc_dmi_max_khz;

	policy->cur = cppc_cpufreq_perf_to_khz(cpu,

					cpu->perf_caps.highest_perf);

	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;



	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);