From 13ad7701f9d0ab7806eb91f1fe1ca43d41b31fa2 Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Sun, 3 Apr 2016 13:06:46 -0700 Subject: [PATCH] cpufreq: intel_pstate: Documenation for structures No code change. Only added kernel doc style comments for structures. Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 135 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index c6c169a..8b5a415 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -64,6 +64,25 @@ static inline int ceiling_fp(int32_t x) return ret; } +/** + * struct sample - Store performance sample + * @core_pct_busy: Ratio of APERF/MPERF in percent, which is actual + * performance during last sample period + * @busy_scaled: Scaled busy value which is used to calculate next + * P state. This can be different than core_pct_busy + * to account for cpu idle period + * @aperf: Difference of actual performance frequency clock count + * read from APERF MSR between last and current sample + * @mperf: Difference of maximum performance frequency clock count + * read from MPERF MSR between last and current sample + * @tsc: Difference of time stamp counter between last and + * current sample + * @freq: Effective frequency calculated from APERF/MPERF + * @time: Current time from scheduler + * + * This structure is used in the cpudata structure to store performance sample + * data for choosing next P State. + */ struct sample { int32_t core_pct_busy; int32_t busy_scaled; @@ -74,6 +93,20 @@ struct sample { u64 time; }; +/** + * struct pstate_data - Store P state data + * @current_pstate: Current requested P state + * @min_pstate: Min P state possible for this platform + * @max_pstate: Max P state possible for this platform + * @max_pstate_physical:This is physical Max P state for a processor + * This can be higher than the max_pstate which can + * be limited by platform thermal design power limits + * @scaling: Scaling factor to convert frequency to cpufreq + * frequency units + * @turbo_pstate: Max Turbo P state possible for this platform + * + * Stores the per cpu model P state limits and current P state. + */ struct pstate_data { int current_pstate; int min_pstate; @@ -83,6 +116,19 @@ struct pstate_data { int turbo_pstate; }; +/** + * struct vid_data - Stores voltage information data + * @min: VID data for this platform corresponding to + * the lowest P state + * @max: VID data corresponding to the highest P State. + * @turbo: VID data for turbo P state + * @ratio: Ratio of (vid max - vid min) / + * (max P state - Min P State) + * + * Stores the voltage data for DVFS (Dynamic Voltage and Frequency Scaling) + * This data is used in Atom platforms, where in addition to target P state, + * the voltage data needs to be specified to select next P State. + */ struct vid_data { int min; int max; @@ -90,6 +136,18 @@ struct vid_data { int32_t ratio; }; +/** + * struct _pid - Stores PID data + * @setpoint: Target set point for busyness or performance + * @integral: Storage for accumulated error values + * @p_gain: PID proportional gain + * @i_gain: PID integral gain + * @d_gain: PID derivative gain + * @deadband: PID deadband + * @last_err: Last error storage for integral part of PID calculation + * + * Stores PID coefficients and last error for PID controller. + */ struct _pid { int setpoint; int32_t integral; @@ -100,6 +158,23 @@ struct _pid { int32_t last_err; }; +/** + * struct cpudata - Per CPU instance data storage + * @cpu: CPU number for this instance data + * @update_util: CPUFreq utility callback information + * @pstate: Stores P state limits for this CPU + * @vid: Stores VID limits for this CPU + * @pid: Stores PID parameters for this CPU + * @last_sample_time: Last Sample time + * @prev_aperf: Last APERF value read from APERF MSR + * @prev_mperf: Last MPERF value read from MPERF MSR + * @prev_tsc: Last timestamp counter (TSC) value + * @prev_cummulative_iowait: IO Wait time difference from last and + * current sample + * @sample: Storage for storing last Sample data + * + * This structure stores per CPU instance data for all CPUs. + */ struct cpudata { int cpu; @@ -118,6 +193,19 @@ struct cpudata { }; static struct cpudata **all_cpu_data; + +/** + * struct pid_adjust_policy - Stores static PID configuration data + * @sample_rate_ms: PID calculation sample rate in ms + * @sample_rate_ns: Sample rate calculation in ns + * @deadband: PID deadband + * @setpoint: PID Setpoint + * @p_gain_pct: PID proportional gain + * @i_gain_pct: PID integral gain + * @d_gain_pct: PID derivative gain + * + * Stores per CPU model static PID configuration data. + */ struct pstate_adjust_policy { int sample_rate_ms; s64 sample_rate_ns; @@ -128,6 +216,20 @@ struct pstate_adjust_policy { int i_gain_pct; }; +/** + * struct pstate_funcs - Per CPU model specific callbacks + * @get_max: Callback to get maximum non turbo effective P state + * @get_max_physical: Callback to get maximum non turbo physical P state + * @get_min: Callback to get minimum P state + * @get_turbo: Callback to get turbo P state + * @get_scaling: Callback to get frequency scaling factor + * @get_val: Callback to convert P state to actual MSR write value + * @get_vid: Callback to get VID data for Atom platforms + * @get_target_pstate: Callback to a function to calculate next P state to use + * + * Core and Atom CPU models have different way to get P State limits. This + * structure is used to store those callbacks. + */ struct pstate_funcs { int (*get_max)(void); int (*get_max_physical)(void); @@ -139,6 +241,11 @@ struct pstate_funcs { int32_t (*get_target_pstate)(struct cpudata *); }; +/** + * struct cpu_defaults- Per CPU model default config data + * @pid_policy: PID config data + * @funcs: Callback function data + */ struct cpu_defaults { struct pstate_adjust_policy pid_policy; struct pstate_funcs funcs; @@ -151,6 +258,34 @@ static struct pstate_adjust_policy pid_params; static struct pstate_funcs pstate_funcs; static int hwp_active; + +/** + * struct perf_limits - Store user and policy limits + * @no_turbo: User requested turbo state from intel_pstate sysfs + * @turbo_disabled: Platform turbo status either from msr + * MSR_IA32_MISC_ENABLE or when maximum available pstate + * matches the maximum turbo pstate + * @max_perf_pct: Effective maximum performance limit in percentage, this + * is minimum of either limits enforced by cpufreq policy + * or limits from user set limits via intel_pstate sysfs + * @min_perf_pct: Effective minimum performance limit in percentage, this + * is maximum of either limits enforced by cpufreq policy + * or limits from user set limits via intel_pstate sysfs + * @max_perf: This is a scaled value between 0 to 255 for max_perf_pct + * This value is used to limit max pstate + * @min_perf: This is a scaled value between 0 to 255 for min_perf_pct + * This value is used to limit min pstate + * @max_policy_pct: The maximum performance in percentage enforced by + * cpufreq setpolicy interface + * @max_sysfs_pct: The maximum performance in percentage enforced by + * intel pstate sysfs interface + * @min_policy_pct: The minimum performance in percentage enforced by + * cpufreq setpolicy interface + * @min_sysfs_pct: The minimum performance in percentage enforced by + * intel pstate sysfs interface + * + * Storage for user and policy defined limits. + */ struct perf_limits { int no_turbo; int turbo_disabled; -- 2.7.4