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[Xen-devel] [PATCH v4 07/11] x86/intel_pstate: the main boby of the intel_pstate driver



The intel_pstate driver is ported following its kernel code logic
(commit: 93f0822d).In order to port the Linux source file with
minimal modifications, some of the variable types are kept intact
(e.g. "int current_pstae", would otherwise be changed to
"unsigned int").

In the kernel, a user can adjust the limits via sysfs
(limits.min_sysfs_pct/max_sysfs_pct). In Xen, the
policy->limits.min_perf_pct/max_perf_pct acts as the transit station.
A user interacts with it via xenpm.

The new xen/include/asm-x86/cpufreq.h header file is added.

v4 changes:
1) changed the identation to be a "Tab" (same as Linux intel_pstate),
   instead of 4 "+$";
2) added a new header file, xen/include/asm-x86/cpufreq.h.

Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
---
 xen/arch/x86/acpi/cpufreq/Makefile       |   1 +
 xen/arch/x86/acpi/cpufreq/intel_pstate.c | 870 +++++++++++++++++++++++++++++++
 xen/include/asm-x86/cpufreq.h            |  34 ++
 xen/include/asm-x86/msr-index.h          |   3 +
 4 files changed, 908 insertions(+)
 create mode 100644 xen/arch/x86/acpi/cpufreq/intel_pstate.c
 create mode 100644 xen/include/asm-x86/cpufreq.h

diff --git a/xen/arch/x86/acpi/cpufreq/Makefile 
b/xen/arch/x86/acpi/cpufreq/Makefile
index f75da9b..99fa9f4 100644
--- a/xen/arch/x86/acpi/cpufreq/Makefile
+++ b/xen/arch/x86/acpi/cpufreq/Makefile
@@ -1,2 +1,3 @@
 obj-y += cpufreq.o
+obj-y += intel_pstate.o
 obj-y += powernow.o
diff --git a/xen/arch/x86/acpi/cpufreq/intel_pstate.c 
b/xen/arch/x86/acpi/cpufreq/intel_pstate.c
new file mode 100644
index 0000000..19c74cc
--- /dev/null
+++ b/xen/arch/x86/acpi/cpufreq/intel_pstate.c
@@ -0,0 +1,870 @@
+#include <xen/kernel.h>
+#include <xen/types.h>
+#include <xen/init.h>
+#include <xen/bitmap.h>
+#include <xen/cpumask.h>
+#include <xen/timer.h>
+#include <asm/msr.h>
+#include <asm/msr-index.h>
+#include <asm/processor.h>
+#include <asm/div64.h>
+#include <asm/cpufreq.h>
+#include <acpi/cpufreq/cpufreq.h>
+
+#define BYT_RATIOS       0x66a
+#define BYT_VIDS         0x66b
+#define BYT_TURBO_RATIOS  0x66c
+#define BYT_TURBO_VIDS   0x66d
+
+#define FRAC_BITS 8
+#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
+#define fp_toint(X) ((X) >> FRAC_BITS)
+
+static inline int32_t mul_fp(int32_t x, int32_t y)
+{
+       return ((int64_t)x * (int64_t)y) >> FRAC_BITS;
+}
+
+static inline int32_t div_fp(int32_t x, int32_t y)
+{
+       return div_s64((int64_t)x << FRAC_BITS, y);
+}
+
+static inline int ceiling_fp(int32_t x)
+{
+       int mask, ret;
+
+       ret = fp_toint(x);
+       mask = (1 << FRAC_BITS) - 1;
+       if (x & mask)
+               ret += 1;
+       return ret;
+}
+
+struct sample {
+       int32_t core_pct_busy;
+       u64 aperf;
+       u64 mperf;
+       int freq;
+       s_time_t time;
+};
+
+struct pstate_data {
+       int     current_pstate;
+       int     min_pstate;
+       int     max_pstate;
+       int     scaling;
+       int     turbo_pstate;
+};
+
+struct vid_data {
+       int min;
+       int max;
+       int turbo;
+       int32_t ratio;
+};
+
+struct _pid {
+       int setpoint;
+       int32_t integral;
+       int32_t p_gain;
+       int32_t i_gain;
+       int32_t d_gain;
+       int deadband;
+       int32_t last_err;
+};
+
+struct cpudata {
+       int cpu;
+
+       struct timer timer;
+
+       struct pstate_data pstate;
+       struct vid_data vid;
+       struct _pid pid;
+
+       s_time_t last_sample_time;
+       u64     prev_aperf;
+       u64     prev_mperf;
+       struct sample sample;
+};
+
+static struct cpudata **all_cpu_data;
+
+struct pstate_adjust_policy {
+       int sample_rate_ms;
+       int deadband;
+       int setpoint;
+       int p_gain_pct;
+       int d_gain_pct;
+       int i_gain_pct;
+};
+
+struct pstate_funcs {
+       int (*get_max)(void);
+       int (*get_min)(void);
+       int (*get_turbo)(void);
+       int (*get_scaling)(void);
+       void (*set)(struct perf_limits *, struct cpudata *, int pstate);
+       void (*get_vid)(struct cpudata *);
+};
+
+struct cpu_defaults {
+       struct pstate_adjust_policy pid_policy;
+       struct pstate_funcs funcs;
+};
+
+static struct pstate_adjust_policy pid_params;
+static struct pstate_funcs pstate_funcs;
+
+static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
+                            int deadband, int integral) {
+       pid->setpoint = setpoint;
+       pid->deadband  = deadband;
+       pid->integral  = int_tofp(integral);
+       pid->last_err  = int_tofp(setpoint) - int_tofp(busy);
+}
+
+static inline void pid_p_gain_set(struct _pid *pid, int percent)
+{
+       pid->p_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static inline void pid_i_gain_set(struct _pid *pid, int percent)
+{
+       pid->i_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static inline void pid_d_gain_set(struct _pid *pid, int percent)
+{
+       pid->d_gain = div_fp(int_tofp(percent), int_tofp(100));
+}
+
+static signed int pid_calc(struct _pid *pid, int32_t busy)
+{
+       signed int result;
+       int32_t pterm, dterm, fp_error;
+       int32_t integral_limit;
+
+       fp_error = int_tofp(pid->setpoint) - busy;
+
+       if (ABS(fp_error) <= int_tofp(pid->deadband))
+               return 0;
+
+       pterm = mul_fp(pid->p_gain, fp_error);
+
+       pid->integral += fp_error;
+
+       /*
+        * We limit the integral here so that it will never
+        * get higher than 30.  This prevents it from becoming
+        * too large an input over long periods of time and allows
+        * it to get factored out sooner.
+        * The value of 30 was chosen through experimentation.
+        */
+       integral_limit = int_tofp(30);
+       if (pid->integral > integral_limit)
+               pid->integral = integral_limit;
+       if (pid->integral < -integral_limit)
+               pid->integral = -integral_limit;
+
+       dterm = mul_fp(pid->d_gain, fp_error - pid->last_err);
+       pid->last_err = fp_error;
+
+       result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
+       result = result + (1 << (FRAC_BITS-1));
+       return (signed int)fp_toint(result);
+}
+
+static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
+{
+       pid_p_gain_set(&cpu->pid, pid_params.p_gain_pct);
+       pid_d_gain_set(&cpu->pid, pid_params.d_gain_pct);
+       pid_i_gain_set(&cpu->pid, pid_params.i_gain_pct);
+
+       pid_reset(&cpu->pid, pid_params.setpoint, 100, pid_params.deadband, 0);
+}
+
+static inline void intel_pstate_reset_all_pid(void)
+{
+       unsigned int cpu;
+
+       for_each_online_cpu(cpu) {
+               if (all_cpu_data[cpu])
+                       intel_pstate_busy_pid_reset(all_cpu_data[cpu]);
+       }
+}
+
+static inline void update_turbo_state(struct cpufreq_policy *policy)
+{
+       u64 misc_en;
+       struct cpudata *cpu;
+
+       cpu = all_cpu_data[policy->cpu];
+       rdmsrl(MSR_IA32_MISC_ENABLE, misc_en);
+       policy->limits.turbo_disabled =
+               (misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE ||
+                       cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
+}
+
+#define BYT_TURBO_CONTROL_BIT 32
+#define BYT_MIN_PSTATE(val) (((value) >> 8) & 0x7f)
+#define BYT_MAX_PSTATE(val) (((value) >> 16) & 0x7f)
+#define BYT_TURBO_PSTATE(value) ((value) & 0x7f)
+static int byt_get_min_pstate(void)
+{
+       u64 value;
+
+       rdmsrl(BYT_RATIOS, value);
+       return BYT_MIN_PSTATE(val);
+}
+
+static int byt_get_max_pstate(void)
+{
+       u64 value;
+
+       rdmsrl(BYT_RATIOS, value);
+       return BYT_MAX_PSTATE(val);
+}
+
+static int byt_get_turbo_pstate(void)
+{
+       u64 value;
+
+       rdmsrl(BYT_TURBO_RATIOS, value);
+       return BYT_TURBO_PSTATE(value);
+}
+
+static void byt_set_pstate(struct perf_limits *limits,
+                               struct cpudata *cpudata, int pstate)
+{
+       u64 val;
+       int32_t vid_fp;
+       u32 vid;
+
+       val = pstate << 8;
+       if (limits->no_turbo && !limits->turbo_disabled)
+               val |= (u64)1 << BYT_TURBO_CONTROL_BIT;
+
+       vid_fp = cpudata->vid.min + mul_fp(
+               int_tofp(pstate - cpudata->pstate.min_pstate),
+               cpudata->vid.ratio);
+
+       vid_fp = clamp_t(int32_t, vid_fp, cpudata->vid.min, cpudata->vid.max);
+       vid = ceiling_fp(vid_fp);
+
+       if (pstate > cpudata->pstate.max_pstate)
+               vid = cpudata->vid.turbo;
+
+       val |= vid;
+
+       wrmsrl(MSR_IA32_PERF_CTL, val);
+}
+
+#define BYT_BCLK_FREQS 5
+#define TO_FREQ_TABLE_IDX_MASK 0x7
+static const int byt_freq_table[BYT_BCLK_FREQS] = { 833, 1000, 1333, 1167, 
800};
+
+static int byt_get_scaling(void)
+{
+       u64 value;
+       int i;
+
+       rdmsrl(MSR_FSB_FREQ, value);
+       i = value & TO_FREQ_TABLE_IDX_MASK;
+
+       BUG_ON(i > BYT_BCLK_FREQS);
+
+       return byt_freq_table[i] * 100;
+}
+
+static void byt_get_vid(struct cpudata *cpudata)
+{
+       u64 value;
+
+       rdmsrl(BYT_VIDS, value);
+       cpudata->vid.min = int_tofp(BYT_MIN_PSTATE(val));
+       cpudata->vid.max = int_tofp(BYT_MAX_PSTATE(val));
+       cpudata->vid.ratio = div_fp(
+               cpudata->vid.max - cpudata->vid.min,
+               int_tofp(cpudata->pstate.max_pstate -
+                       cpudata->pstate.min_pstate));
+
+       rdmsrl(BYT_TURBO_VIDS, value);
+       cpudata->vid.turbo = BYT_TURBO_PSTATE(value);
+}
+
+#define SCALING_FACTOR 100000
+#define CORE_TURBO_CONTROL_BIT 32
+#define CORE_MIN_PSTATE(val) (((value) >> 40) & 0xff)
+#define CORE_MAX_PSTATE(val) (((value) >> 8) & 0xff)
+#define CORE_TURBO_PSTATE(value) ((value) & 0xff)
+static int core_get_min_pstate(void)
+{
+       u64 value;
+
+       rdmsrl(MSR_INTEL_PLATFORM_INFO, value);
+       return CORE_MIN_PSTATE(val);
+}
+
+static int core_get_max_pstate(void)
+{
+       u64 value;
+
+       rdmsrl(MSR_INTEL_PLATFORM_INFO, value);
+       return CORE_MAX_PSTATE(val);
+}
+
+static int core_get_turbo_pstate(void)
+{
+       u64 value;
+       int nont, ret;
+
+       rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
+       nont = core_get_max_pstate();
+       ret = CORE_TURBO_PSTATE(value);
+       if (ret <= nont)
+               ret = nont;
+       return ret;
+}
+
+static inline int core_get_scaling(void)
+{
+       return SCALING_FACTOR;
+}
+
+static void core_set_pstate(struct perf_limits *limits,
+                               struct cpudata *cpudata, int pstate)
+{
+       u64 val;
+
+       val = pstate << 8;
+       if (limits->no_turbo && !limits->turbo_disabled)
+               val |= (u64)1 << CORE_TURBO_CONTROL_BIT;
+
+       wrmsrl(MSR_IA32_PERF_CTL, val);
+}
+
+static const struct cpu_defaults core_params = {
+       .pid_policy = {
+               .sample_rate_ms = 10,
+               .deadband = 0,
+               .setpoint = 97,
+               .p_gain_pct = 20,
+               .d_gain_pct = 0,
+               .i_gain_pct = 0,
+       },
+       .funcs = {
+               .get_max = core_get_max_pstate,
+               .get_min = core_get_min_pstate,
+               .get_turbo = core_get_turbo_pstate,
+               .get_scaling = core_get_scaling,
+               .set = core_set_pstate,
+       },
+};
+
+static const struct cpu_defaults byt_params = {
+       .pid_policy = {
+               .sample_rate_ms = 10,
+               .deadband = 0,
+               .setpoint = 97,
+               .p_gain_pct = 14,
+               .d_gain_pct = 0,
+               .i_gain_pct = 4,
+       },
+       .funcs = {
+               .get_max = byt_get_max_pstate,
+               .get_min = byt_get_min_pstate,
+               .get_turbo = byt_get_turbo_pstate,
+               .set = byt_set_pstate,
+               .get_scaling = byt_get_scaling,
+               .get_vid = byt_get_vid,
+       },
+};
+
+static void intel_pstate_get_min_max(struct perf_limits *limits,
+                               struct cpudata *cpu, int *min, int *max)
+{
+       int max_perf = cpu->pstate.turbo_pstate;
+       int max_perf_adj;
+       int min_perf;
+
+       if (limits->no_turbo || limits->turbo_disabled)
+               max_perf = cpu->pstate.max_pstate;
+
+       /* performance can be limited by user through xenpm */
+       max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits->max_perf));
+       *max = clamp_t(int, max_perf_adj,
+                       cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
+
+       min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits->min_perf));
+       *min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
+}
+
+static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
+{
+       int max_perf, min_perf;
+       struct cpufreq_policy *policy;
+       struct perf_limits *limits;
+
+       policy = per_cpu(cpufreq_cpu_policy, cpu->cpu);
+       limits = &policy->limits;
+
+       update_turbo_state(policy);
+
+       if (limits->turbo_disabled)
+               policy->turbo = CPUFREQ_TURBO_UNSUPPORTED;
+       else if (limits->no_turbo)
+               policy->turbo = CPUFREQ_TURBO_DISABLED;
+       else
+               policy->turbo = CPUFREQ_TURBO_ENABLED;
+
+       intel_pstate_get_min_max(limits, cpu, &min_perf, &max_perf);
+
+       pstate = clamp_t(int, pstate, min_perf, max_perf);
+
+       if (pstate == cpu->pstate.current_pstate)
+               return;
+
+       cpu->pstate.current_pstate = pstate;
+       policy->cur = pstate * SCALING_FACTOR;
+
+       pstate_funcs.set(limits, cpu, pstate);
+}
+
+static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
+{
+       cpu->pstate.min_pstate = pstate_funcs.get_min();
+       cpu->pstate.max_pstate = pstate_funcs.get_max();
+       cpu->pstate.turbo_pstate = pstate_funcs.get_turbo();
+       cpu->pstate.scaling = pstate_funcs.get_scaling();
+
+       if (pstate_funcs.get_vid)
+               pstate_funcs.get_vid(cpu);
+       intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
+}
+
+static inline void intel_pstate_calc_busy(struct cpudata *cpu)
+{
+       struct sample *sample = &cpu->sample;
+       int64_t core_pct;
+
+       core_pct = int_tofp(sample->aperf) * int_tofp(100);
+       core_pct = div64_u64(core_pct, int_tofp(sample->mperf));
+
+       sample->freq = fp_toint(
+               mul_fp(int_tofp(
+                       cpu->pstate.max_pstate * cpu->pstate.scaling / 100),
+                       core_pct));
+
+       sample->core_pct_busy = (int32_t)core_pct;
+}
+
+static inline void intel_pstate_sample(struct cpudata *cpu)
+{
+       u64 aperf, mperf;
+       unsigned long flags;
+
+       local_irq_save(flags);
+       rdmsrl(MSR_IA32_APERF, aperf);
+       rdmsrl(MSR_IA32_MPERF, mperf);
+       local_irq_restore(flags);
+
+       cpu->last_sample_time = cpu->sample.time;
+       cpu->sample.time = get_s_time();
+       cpu->sample.aperf = aperf;
+       cpu->sample.mperf = mperf;
+       cpu->sample.aperf -= cpu->prev_aperf;
+       cpu->sample.mperf -= cpu->prev_mperf;
+
+       intel_pstate_calc_busy(cpu);
+
+       cpu->prev_aperf = aperf;
+       cpu->prev_mperf = mperf;
+}
+
+static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
+{
+       set_timer(&cpu->timer, NOW() + MILLISECS(pid_params.sample_rate_ms));
+}
+
+static inline int32_t intel_pstate_get_scaled_busy(struct cpudata *cpu)
+{
+       int32_t core_busy, max_pstate, current_pstate, sample_ratio;
+       u32 duration_us;
+       u32 sample_time_us;
+
+       /*
+        * core_busy is the ratio of actual performance to max
+        * max_pstate is the max non turbo pstate available
+        * current_pstate was the pstate that was requested during
+        * the last sample period.
+        *
+        * We normalize core_busy, which was our actual percent
+        * performance to what we requested during the last sample
+        * period. The result will be a percentage of busy at a
+        * specified pstate.
+        */
+       core_busy = cpu->sample.core_pct_busy;
+       max_pstate = int_tofp(cpu->pstate.max_pstate);
+       current_pstate = int_tofp(cpu->pstate.current_pstate);
+       core_busy = mul_fp(core_busy, div_fp(max_pstate, current_pstate));
+
+       /*
+        * Since we have a deferred timer, it will not fire unless
+        * we are in C0.  So, determine if the actual elapsed time
+        * is significantly greater (3x) than our sample interval. If it
+        * is, then we were idle for a long enough period of time
+        * to adjust our busyness.
+        */
+       sample_time_us = pid_params.sample_rate_ms  * 1000ULL;
+       duration_us = (u32)((s_time_t)(cpu->sample.time - cpu->last_sample_time)
+                       / 1000);
+       if (duration_us > sample_time_us * 3) {
+               sample_ratio = div_fp(int_tofp(sample_time_us),
+                                     int_tofp(duration_us));
+               core_busy = mul_fp(core_busy, sample_ratio);
+       }
+
+       return core_busy;
+}
+
+static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
+{
+       int32_t busy_scaled;
+       struct _pid *pid;
+       signed int ctl;
+
+       pid = &cpu->pid;
+       busy_scaled = intel_pstate_get_scaled_busy(cpu);
+
+       ctl = pid_calc(pid, busy_scaled);
+
+       /* Negative values of ctl increase the pstate and vice versa */
+       intel_pstate_set_pstate(cpu, cpu->pstate.current_pstate - ctl);
+}
+
+static void intel_pstate_timer_func(void *data)
+{
+       struct cpudata *cpu = (struct cpudata *) data;
+
+       intel_pstate_sample(cpu);
+
+       intel_pstate_adjust_busy_pstate(cpu);
+
+       intel_pstate_set_sample_time(cpu);
+}
+
+#define ICPU(model, policy) \
+       { X86_VENDOR_INTEL, 6, model, X86_FEATURE_APERFMPERF,\
+                       &policy##_params }
+
+static const struct x86_cpu_id intel_pstate_cpu_ids[] __initconst = {
+       ICPU(0x2a, core),
+       ICPU(0x2d, core),
+       ICPU(0x37, byt),
+       ICPU(0x3a, core),
+       ICPU(0x3c, core),
+       ICPU(0x3d, core),
+       ICPU(0x3e, core),
+       ICPU(0x3f, core),
+       ICPU(0x45, core),
+       ICPU(0x46, core),
+       ICPU(0x47, core),
+       ICPU(0x4c, byt),
+       ICPU(0x4e, core),
+       ICPU(0x4f, core),
+       ICPU(0x56, core),
+       {}
+};
+
+static int intel_pstate_init_cpu(unsigned int cpunum)
+{
+       struct cpudata *cpu;
+       s_time_t expires;
+
+       if (!all_cpu_data[cpunum])
+               all_cpu_data[cpunum] = xzalloc(struct cpudata);
+       if (!all_cpu_data[cpunum])
+               return -ENOMEM;
+
+       cpu = all_cpu_data[cpunum];
+
+       cpu->cpu = cpunum;
+       intel_pstate_get_cpu_pstates(cpu);
+
+       init_timer(&cpu->timer, intel_pstate_timer_func, cpu, cpunum);
+       expires = NOW() + MILLISECS(10);
+
+       intel_pstate_busy_pid_reset(cpu);
+       intel_pstate_sample(cpu);
+
+       set_timer(&cpu->timer, expires);
+
+       return 0;
+}
+
+static int intel_pstate_set_policy(struct cpufreq_policy *policy)
+{
+       struct perf_limits *limits = &policy->limits;
+       uint32_t cur_gov = policy->internal_gov->cur_gov;
+
+       if (!policy->cpuinfo.max_freq)
+               return -ENODEV;
+
+       switch (cur_gov) {
+       case INTERNAL_GOV_PERFORMANCE:
+               limits->no_turbo = 0;
+               limits->max_perf_pct = 100;
+               limits->max_perf = int_tofp(1);
+               limits->min_perf_pct = 100;
+               limits->min_perf = int_tofp(1);
+               break;
+       case INTERNAL_GOV_POWERSAVE:
+               limits->min_perf =
+                       div_fp(int_tofp(limits->min_policy_pct),
+                                               int_tofp(100));
+               limits->max_perf = limits->min_perf;
+               limits->min_perf_pct = limits->min_policy_pct;
+               limits->max_perf_pct = limits->min_perf_pct;
+               break;
+       case INTERNAL_GOV_USERSPACE:
+               limits->max_perf =
+                       div_fp(int_tofp(limits->max_perf_pct),
+                                               int_tofp(100));
+               limits->min_perf = limits->max_perf;
+               limits->min_perf_pct = limits->max_perf_pct;
+               break;
+       case INTERNAL_GOV_ONDEMAND:
+       default:
+               limits->min_perf =
+                       div_fp(int_tofp(limits->min_perf_pct), int_tofp(100));
+               limits->max_perf =
+                       div_fp(int_tofp(limits->max_perf_pct), int_tofp(100));
+               break;
+       }
+
+       return 0;
+}
+
+static int intel_pstate_verify_policy(struct cpufreq_policy *policy)
+{
+       uint32_t cur_gov = policy->internal_gov->cur_gov;
+
+       cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
+                                                policy->cpuinfo.max_freq);
+
+       switch(cur_gov) {
+       case INTERNAL_GOV_PERFORMANCE:
+       case INTERNAL_GOV_POWERSAVE:
+       case INTERNAL_GOV_USERSPACE:
+       case INTERNAL_GOV_ONDEMAND:
+                                       return 0;
+       default:
+                                       return -EINVAL;
+       }
+}
+
+static void intel_pstate_internal_gov_release(struct internal_governor *gov)
+{
+       xfree(gov->avail_gov);
+       xfree(gov);
+}
+
+static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
+{
+       int cpu_num = policy->cpu;
+       struct cpudata *cpu = all_cpu_data[cpu_num];
+
+       kill_timer(&all_cpu_data[cpu_num]->timer);
+
+       intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
+
+       intel_pstate_internal_gov_release(policy->internal_gov);
+
+       return 0;
+}
+
+static int intel_pstate_turbo_update(int cpuid, struct cpufreq_policy *policy)
+{
+       struct cpudata *cpu = all_cpu_data[policy->cpu];
+       struct perf_limits *limits = &policy->limits;
+
+       update_turbo_state(policy);
+       if (limits->turbo_disabled) {
+               printk("Turbo disabled by BIOS or not supported on CPU\n");
+               return -EINVAL;
+       }
+       limits->no_turbo = policy->turbo == CPUFREQ_TURBO_ENABLED ? 0 : 1;
+
+       if (limits->no_turbo)
+               policy->cpuinfo.max_freq =
+                       cpu->pstate.max_pstate * cpu->pstate.scaling;
+       else
+               policy->cpuinfo.max_freq =
+                       cpu->pstate.turbo_pstate * cpu->pstate.scaling;
+
+       policy->max = clamp_t(unsigned int, policy->max,
+                       policy->cpuinfo.min_freq, policy->cpuinfo.max_freq);
+
+       return 0;
+}
+
+static int get_turbo_pct(struct cpudata *cpu)
+{
+       int total, no_turbo, turbo_pct;
+       uint32_t turbo_fp;
+
+       total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;
+       no_turbo = cpu->pstate.max_pstate - cpu->pstate.min_pstate + 1;
+       turbo_fp = div_fp(int_tofp(no_turbo), int_tofp(total));
+       turbo_pct = 100 - fp_toint(mul_fp(turbo_fp, int_tofp(100)));
+       return turbo_pct;
+}
+
+#define INTEL_PSTATE_GOV_NUM 4
+static struct internal_governor* intel_pstate_internal_gov_init(void)
+{
+       unsigned int i = 0;
+       struct internal_governor *gov;
+       char *avail_gov;
+
+       gov = xzalloc(struct internal_governor);
+       if (!gov)
+               return NULL;
+       avail_gov = xzalloc_array(char,
+                       INTEL_PSTATE_GOV_NUM * CPUFREQ_NAME_LEN);
+       if (!avail_gov)
+               return NULL;
+
+       gov->avail_gov = avail_gov;
+
+       i += scnprintf(&avail_gov[0], CPUFREQ_NAME_LEN, "%s ", "performance");
+       i += scnprintf(&avail_gov[i], CPUFREQ_NAME_LEN, "%s ", "powersave");
+       i += scnprintf(&avail_gov[i], CPUFREQ_NAME_LEN, "%s ", "userspace");
+       i += scnprintf(&avail_gov[i], CPUFREQ_NAME_LEN, "%s ", "ondemand");
+       avail_gov[i-1] = '\0';
+       gov->gov_num = INTEL_PSTATE_GOV_NUM;
+       gov->cur_gov = INTERNAL_GOV_ONDEMAND;
+       return gov;
+}
+
+static int intel_pstate_cpu_setup(struct cpufreq_policy *policy)
+{
+       struct cpudata *cpu;
+       struct perf_limits *limits = &policy->limits;
+       int rc;
+
+       rc = intel_pstate_init_cpu(policy->cpu);
+       if (rc)
+               return rc;
+
+       policy->internal_gov = intel_pstate_internal_gov_init();
+       if (!policy->internal_gov)
+               return -ENOMEM;
+
+       cpu = all_cpu_data[policy->cpu];
+       policy->min = cpu->pstate.min_pstate * cpu->pstate.scaling;
+       policy->max = cpu->pstate.turbo_pstate * cpu->pstate.scaling;
+
+       /* cpuinfo and default policy values */
+       policy->cpuinfo.min_freq =
+               cpu->pstate.min_pstate * cpu->pstate.scaling;
+       policy->cpuinfo.max_freq =
+               cpu->pstate.turbo_pstate * cpu->pstate.scaling;
+       policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+       cpumask_set_cpu(policy->cpu, policy->cpus);
+
+       limits->no_turbo = 0;
+       limits->turbo_disabled = 0;
+       limits->turbo_pct = get_turbo_pct(cpu);
+       limits->min_policy_pct =
+               (policy->min * 100) / policy->cpuinfo.max_freq;
+       limits->min_policy_pct =
+               clamp_t(uint32_t, limits->min_policy_pct, 0, 100);
+       limits->max_policy_pct =
+               (policy->max * 100) / policy->cpuinfo.max_freq;
+       limits->max_policy_pct =
+               clamp_t(uint32_t, limits->max_policy_pct, 0, 100);
+       limits->max_perf_pct   = limits->max_policy_pct;
+       limits->min_perf_pct   = limits->min_policy_pct;
+
+       return 0;
+}
+
+static struct cpufreq_driver intel_pstate_driver = {
+       .verify    = intel_pstate_verify_policy,
+       .setpolicy      = intel_pstate_set_policy,
+       .init            = intel_pstate_cpu_setup,
+       .exit            = intel_pstate_cpu_exit,
+       .update    = intel_pstate_turbo_update,
+       .name            = "intel_pstate",
+};
+
+static int intel_pstate_msrs_not_valid(void)
+{
+       if (!pstate_funcs.get_max() ||
+               !pstate_funcs.get_min() ||
+               !pstate_funcs.get_turbo())
+               return -ENODEV;
+
+       return 0;
+}
+
+static void __init copy_pid_params(struct pstate_adjust_policy *policy)
+{
+       pid_params.sample_rate_ms = policy->sample_rate_ms;
+       pid_params.p_gain_pct = policy->p_gain_pct;
+       pid_params.i_gain_pct = policy->i_gain_pct;
+       pid_params.d_gain_pct = policy->d_gain_pct;
+       pid_params.deadband = policy->deadband;
+       pid_params.setpoint = policy->setpoint;
+}
+
+static void __init copy_cpu_funcs(struct pstate_funcs *funcs)
+{
+       pstate_funcs.get_max   = funcs->get_max;
+       pstate_funcs.get_min   = funcs->get_min;
+       pstate_funcs.get_turbo = funcs->get_turbo;
+       pstate_funcs.get_scaling = funcs->get_scaling;
+       pstate_funcs.set           = funcs->set;
+       pstate_funcs.get_vid   = funcs->get_vid;
+}
+
+int __init intel_pstate_init(void)
+{
+       int cpu, rc = 0;
+       const struct x86_cpu_id *id;
+       struct cpu_defaults *cpu_info;
+
+       id = x86_match_cpu(intel_pstate_cpu_ids);
+       if (!id)
+               return -ENODEV;
+
+       cpu_info = (struct cpu_defaults *)id->driver_data;
+
+       copy_pid_params(&cpu_info->pid_policy);
+       copy_cpu_funcs(&cpu_info->funcs);
+
+       if (intel_pstate_msrs_not_valid())
+               return -ENODEV;
+
+       all_cpu_data = xzalloc_array(struct cpudata *, NR_CPUS);
+       if (!all_cpu_data)
+               return -ENOMEM;
+
+       rc = cpufreq_register_driver(&intel_pstate_driver);
+       if (rc)
+               goto out;
+
+       return rc;
+out:
+       for_each_online_cpu(cpu) {
+               if (all_cpu_data[cpu]) {
+                       kill_timer(&all_cpu_data[cpu]->timer);
+                       xfree(all_cpu_data[cpu]);
+               }
+       }
+       xfree(all_cpu_data);
+       return -ENODEV;
+}
diff --git a/xen/include/asm-x86/cpufreq.h b/xen/include/asm-x86/cpufreq.h
new file mode 100644
index 0000000..94410f8
--- /dev/null
+++ b/xen/include/asm-x86/cpufreq.h
@@ -0,0 +1,34 @@
+#ifndef _ASM_X86_CPUFREQ_H
+#define _ASM_X86_CPUFREQ_H
+
+/*
+ *  Copyright (C) 2015 Wei Wang <wei.w.wang@xxxxxxxxx>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+extern int intel_pstate_init(void);
+
+/*
+ * Maximum transition latency is in nanoseconds - if it's unknown,
+ * CPUFREQ_ETERNAL shall be used.
+ */
+#define CPUFREQ_ETERNAL        (-1)
+
+#endif /* _ASM_X86_CPUFREQ_H */
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index 83f2f70..57945d9 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -52,6 +52,8 @@
 #define MSR_IA32_MCG_STATUS            0x0000017a
 #define MSR_IA32_MCG_CTL               0x0000017b
 
+#define MSR_NHM_TURBO_RATIO_LIMIT      0x000001ad
+
 #define MSR_IA32_PEBS_ENABLE           0x000003f1
 #define MSR_IA32_DS_AREA               0x00000600
 #define MSR_IA32_PERF_CAPABILITIES     0x00000345
@@ -319,6 +321,7 @@
 #define MSR_IA32_MISC_ENABLE_MONITOR_ENABLE (1<<18)
 #define MSR_IA32_MISC_ENABLE_LIMIT_CPUID  (1<<22)
 #define MSR_IA32_MISC_ENABLE_XTPR_DISABLE (1<<23)
+#define MSR_IA32_MISC_ENABLE_TURBO_DISABLE (1ULL<<38)
 
 #define MSR_IA32_TSC_DEADLINE          0x000006E0
 #define MSR_IA32_ENERGY_PERF_BIAS      0x000001b0
-- 
1.9.1


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