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cpufreq: intel_pstate: Documenation for structures 

No code change. Only added kernel doc style comments for structures.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Srinivas Pandruvada 2016-04-03 13:06:46 -07:00 committed by Rafael J. Wysocki
parent 30a3915385
commit 13ad7701f9
1 changed files with 135 additions and 0 deletions
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135
drivers/cpufreq/intel_pstate.c
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@ -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;