[RFC 2/3] CPPC: Add support for Collaborative Processor Performance Control

From: Ashwin Chaugule
Date: Thu Aug 14 2014 - 15:58:09 EST

Add support for parsing the CPC tables as described in the
ACPI 5.1+ CPPC specification. When successfully parsed along
with low level register accessors, then enable the PID
(proportional-intergral-derivative) controller based algorithm
to manage CPU performance.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
---
drivers/acpi/pcc.c | 109 ++++++
drivers/cpufreq/Kconfig | 10 +
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/cppc.c | 874 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/cpufreq/cppc.h | 181 ++++++++++
5 files changed, 1175 insertions(+)
create mode 100644 drivers/cpufreq/cppc.c
create mode 100644 drivers/cpufreq/cppc.h

diff --git a/drivers/acpi/pcc.c b/drivers/acpi/pcc.c
index 105e11a..7743f12 100644
--- a/drivers/acpi/pcc.c
+++ b/drivers/acpi/pcc.c
@@ -31,6 +31,12 @@
#define PCC_CMD_COMPLETE 0x1
#define PCC_VERSION "0.1"

+#define PCC_HACK 1
+
+#ifdef PCC_HACK
+static void *pcc_comm_addr;
+#endif
+
struct pcc_ss_desc {
struct acpi_pcct_subspace *pcc_ss_ptr;
raw_spinlock_t lock;
@@ -51,8 +57,13 @@ int get_pcc_comm_channel(u32 ss_idx, u64 __iomem *addr, int *len)
struct acpi_pcct_subspace *pcct_subspace = pcc_ss_arr[ss_idx].pcc_ss_ptr;

if (pcct_subspace) {
+#ifndef PCC_HACK
*addr = pcct_subspace->base_address;
*len = pcct_subspace->length;
+#else
+ *addr = (u64 *)pcc_comm_addr;
+ *len = PAGE_SIZE;
+#endif
} else
return -EINVAL;

@@ -61,6 +72,7 @@ int get_pcc_comm_channel(u32 ss_idx, u64 __iomem *addr, int *len)
return 0;
}

+#ifndef PCC_HACK
/* Send PCC cmd on behalf of this (subspace id) PCC client */
u16 send_pcc_cmd(u8 cmd, u8 sci, u32 ss_idx, u64 __iomem *base_addr)
{
@@ -114,6 +126,93 @@ u16 send_pcc_cmd(u8 cmd, u8 sci, u32 ss_idx, u64 __iomem *base_addr)
return generic_comm_base->status;
}

+#else
+
+#include <asm/msr.h>
+
+/* These offsets are from the SSDT9.asl table on the Thinkpad X240 */
+
+/* These are offsets per CPU from which its CPC table begins. */
+int cpu_base[] = {0, 0x64, 0xC8, 0x12C, 0x190, 0x1F4, 0x258, 0x2BC};
+
+/* These are offsets of the registers in each CPC table. */
+#define HIGHEST_PERF_OFFSET 0x0
+#define LOWEST_PERF_OFFSET 0xc
+#define DESIRED_PERF_OFFSET 0x14
+
+static int core_get_min(void)
+{
+ u64 val;
+ rdmsrl(MSR_PLATFORM_INFO, val);
+ return (val >> 40) & 0xff;
+}
+
+static int core_get_max(void)
+{
+ u64 val;
+ rdmsrl(MSR_PLATFORM_INFO, val);
+ return (val >> 8) & 0xff;
+}
+
+static int core_get_turbo(void)
+{
+ u64 value;
+ int nont, ret;
+
+ rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
+ nont = core_get_max();
+ ret = ((value) & 255);
+ if (ret <= nont)
+ ret = nont;
+ return ret;
+}
+
+u16 send_pcc_cmd(u8 cmd, u8 sci, u32 ss_idx, u64 __iomem *base_addr)
+{
+ unsigned int cpu;
+ u64 desired_val;
+
+ raw_spin_lock(&pcc_ss_arr[ss_idx].lock);
+ /*XXX: Instead of waiting for platform to consume the cmd,
+ * just do what the platform would've done.
+ */
+ switch (cmd) {
+ case 0: //PCC_CMD_READ
+
+ /* XXX: Normally the Platform would need to update all the other CPPC registers as well.
+ * But for this experiment, since we're not really using all of them, we'll only update
+ * what we use.
+ */
+ for_each_possible_cpu(cpu) {
+ *(char*)(pcc_comm_addr + cpu_base[cpu] + HIGHEST_PERF_OFFSET) = core_get_turbo();
+ *(char*)(pcc_comm_addr + cpu_base[cpu] + LOWEST_PERF_OFFSET) = core_get_min();
+ }
+ break;
+ case 1: //PCC_CMD_WRITE
+
+ /* XXX: All this hackery is very X86 Thinkpad X240 specific.
+ * Normally, the cpc_write64() would have all the info on
+ * how, where and what to write.
+ */
+ for_each_possible_cpu(cpu) {
+ desired_val = *(u64*)(pcc_comm_addr + cpu_base[cpu] + DESIRED_PERF_OFFSET);
+
+ if (desired_val) {
+ wrmsrl_on_cpu(cpu, MSR_IA32_PERF_CTL, desired_val << 8);
+ *(u64*)(pcc_comm_addr + cpu_base[cpu] + DESIRED_PERF_OFFSET) = 0;
+ }
+ }
+ break;
+ default:
+ pr_err("Unknown PCC cmd from the OS\n");
+ return 0;
+ }
+
+ raw_spin_unlock(&pcc_ss_arr[ss_idx].lock);
+ return 1;
+}
+#endif
+
static int parse_pcc_subspace(struct acpi_subtable_header *header,
const unsigned long end)
{
@@ -185,6 +284,16 @@ static int __init pcc_init(void)
return -EINVAL;
}

+#ifdef PCC_HACK
+ pcc_comm_addr = kzalloc(PAGE_SIZE, GFP_KERNEL);
+
+ if (!pcc_comm_addr) {
+ pr_err("Could not allocate mem for pcc hack\n");
+ return -ENOMEM;
+ }
+
+#endif
+
return ret;
}
device_initcall(pcc_init);
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index ffe350f..d8e8335 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -196,6 +196,16 @@ config GENERIC_CPUFREQ_CPU0

If in doubt, say N.

+config CPPC_CPUFREQ
+ bool "CPPC CPUFreq driver"
+ depends on ACPI && ACPI_PCC
+ default n
+ help
+ CPPC is Collaborative Processor Performance Control. It allows the OS
+ to request CPU performance with an abstract metric and lets the platform
+ (e.g. BMC) interpret and optimize it for power and performance in a
+ platform specific manner.
+
menu "x86 CPU frequency scaling drivers"
depends on X86
source "drivers/cpufreq/Kconfig.x86"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index db6d9a2..b392c8c 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE) += cpufreq_conservative.o
obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o

obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o
+obj-$(CONFIG_CPPC_CPUFREQ) += cppc.o

##################################################################################
# x86 drivers.
diff --git a/drivers/cpufreq/cppc.c b/drivers/cpufreq/cppc.c
new file mode 100644
index 0000000..6917ce0
--- /dev/null
+++ b/drivers/cpufreq/cppc.c
@@ -0,0 +1,874 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
+ *
+ * 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.
+ *
+ * PID algo bits are from intel_pstate.c and modified to use CPPC
+ * accessors.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/acpi.h>
+#include <linux/errno.h>
+
+#include <acpi/processor.h>
+#include <acpi/actypes.h>
+
+#include <trace/events/power.h>
+
+#include <asm/div64.h>
+#include <asm/msr.h>
+
+#include "cppc.h"
+
+#define FRAC_BITS 8
+#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
+#define fp_toint(X) ((X) >> FRAC_BITS)
+
+#define CPPC_EN 1
+#define PCC_CMD_COMPLETE 1
+
+/* There is one CPC descriptor per CPU */
+static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
+
+/* PCC client specifics for the CPPC structure */
+/* Returned by the PCCT Subspace structure */
+static u64 pcc_comm_base_addr;
+
+/* ioremap the pcc_comm_base_addr*/
+static void __iomem *comm_base_addr;
+
+/* The PCC subspace used by the CPC table */
+static s8 pcc_subspace_idx = -1;
+
+extern int get_pcc_comm_channel(u32 ss_idx, u64* addr, int *len);
+extern u16 send_pcc_cmd(u8 cmd, u8 sci, u32 ss_idx, u64 * __iomem base_addr);
+
+/*
+ * The low level platform specific accessors
+ * to the registers defined in the CPC table
+ */
+struct cpc_funcs *cppc_func_ops;
+
+static struct cpudata **all_cpu_data;
+static struct pstate_adjust_policy pid_params;
+
+/* PCC Commands used by CPPC */
+enum cppc_ppc_cmds {
+ PCC_CMD_READ,
+ PCC_CMD_WRITE,
+ RESERVED,
+};
+
+static struct perf_limits limits = {
+ .max_perf_pct = 100,
+ .max_perf = int_tofp(1),
+ .min_perf_pct = 0,
+ .min_perf = 0,
+ .max_policy_pct = 100,
+ .max_sysfs_pct = 100,
+};
+
+u64 cpc_read64(struct cpc_register_resource *reg, void __iomem *base_addr)
+{
+ u64 err = 0;
+ u64 val;
+
+ switch (reg->space_id) {
+ case ACPI_ADR_SPACE_PLATFORM_COMM:
+ err = readq((void *) (reg->address + *(u64 *)base_addr));
+ break;
+ case ACPI_ADR_SPACE_FIXED_HARDWARE:
+ rdmsrl(reg->address, val);
+ return val;
+ break;
+ default:
+ pr_err("unknown space_id detected in cpc reg: %d\n", reg->space_id);
+ break;
+ }
+
+ return err;
+}
+
+int cpc_write64(u64 val, struct cpc_register_resource *reg, void __iomem *base_addr)
+{
+ unsigned int err = 0;
+
+ switch (reg->space_id) {
+ case ACPI_ADR_SPACE_PLATFORM_COMM:
+ writeq(val, (void *)(reg->address + *(u64 *)base_addr));
+ break;
+ case ACPI_ADR_SPACE_FIXED_HARDWARE:
+ wrmsrl(reg->address, val);
+ break;
+ default:
+ pr_err("unknown space_id detected in cpc reg: %d\n", reg->space_id);
+ break;
+ }
+
+ return err;
+}
+
+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, (int64_t)y);
+}
+
+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;
+
+ /* limit the integral term */
+ 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 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 pstate_reset_all_pid(void)
+{
+ unsigned int cpu;
+ for_each_online_cpu(cpu) {
+ if (all_cpu_data[cpu])
+ pstate_busy_pid_reset(all_cpu_data[cpu]);
+ }
+}
+
+/************************** debugfs begin ************************/
+static int pid_param_set(void *data, u64 val)
+{
+ *(u32 *)data = val;
+ pstate_reset_all_pid();
+ return 0;
+}
+
+static int pid_param_get(void *data, u64 *val)
+{
+ *val = *(u32 *)data;
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get,
+ pid_param_set, "%llu\n");
+
+struct pid_param {
+ char *name;
+ void *value;
+};
+
+static struct pid_param pid_files[] = {
+ {"sample_rate_ms", &pid_params.sample_rate_ms},
+ {"d_gain_pct", &pid_params.d_gain_pct},
+ {"i_gain_pct", &pid_params.i_gain_pct},
+ {"deadband", &pid_params.deadband},
+ {"setpoint", &pid_params.setpoint},
+ {"p_gain_pct", &pid_params.p_gain_pct},
+ {NULL, NULL}
+};
+
+static struct dentry *debugfs_parent;
+static void cppc_pstate_debug_expose_params(void)
+{
+ int i = 0;
+
+ debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
+ if (IS_ERR_OR_NULL(debugfs_parent))
+ return;
+ while (pid_files[i].name) {
+ debugfs_create_file(pid_files[i].name, 0660,
+ debugfs_parent, pid_files[i].value,
+ &fops_pid_param);
+ i++;
+ }
+}
+
+/************************** debugfs end ************************/
+
+/************************** sysfs begin ************************/
+#define show_one(file_name, object) \
+ static ssize_t show_##file_name \
+ (struct kobject *kobj, struct attribute *attr, char *buf) \
+ { \
+ return sprintf(buf, "%u\n", limits.object); \
+ }
+
+static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b,
+ const char *buf, size_t count)
+{
+ unsigned int input;
+ int ret;
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
+
+ limits.max_sysfs_pct = clamp_t(int, input, 0 , 100);
+ limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
+ limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+ return count;
+}
+
+static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
+ const char *buf, size_t count)
+{
+ unsigned int input;
+ int ret;
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
+ limits.min_perf_pct = clamp_t(int, input, 0 , 100);
+ limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
+
+ return count;
+}
+
+show_one(max_perf_pct, max_perf_pct);
+show_one(min_perf_pct, min_perf_pct);
+
+define_one_global_rw(max_perf_pct);
+define_one_global_rw(min_perf_pct);
+
+static struct attribute *cppc_pstate_attributes[] = {
+ &max_perf_pct.attr,
+ &min_perf_pct.attr,
+ NULL
+};
+
+static struct attribute_group cppc_pstate_attr_group = {
+ .attrs = cppc_pstate_attributes,
+};
+static struct kobject *cppc_pstate_kobject;
+
+static void cppc_pstate_sysfs_expose_params(void)
+{
+ int rc;
+
+ cppc_pstate_kobject = kobject_create_and_add("cppc_pstate",
+ &cpu_subsys.dev_root->kobj);
+ BUG_ON(!cppc_pstate_kobject);
+ rc = sysfs_create_group(cppc_pstate_kobject,
+ &cppc_pstate_attr_group);
+ BUG_ON(rc);
+}
+
+/************************** sysfs end ************************/
+
+static inline void pstate_calc_busy(struct cpudata *cpu)
+{
+ struct sample *sample = &cpu->sample;
+ int64_t core_pct;
+ int32_t rem;
+
+ core_pct = int_tofp(sample->delivered) * int_tofp(100);
+ core_pct = div_u64_rem(core_pct, int_tofp(sample->reference), &rem);
+
+ if ((rem << 1) >= int_tofp(sample->reference))
+ core_pct += 1;
+
+ sample->freq = fp_toint(
+ mul_fp(int_tofp(cpu->pstate.max_pstate * 1000), core_pct));
+
+ sample->core_pct_busy = (int32_t)core_pct;
+}
+
+static inline void pstate_sample(struct cpudata *cpu)
+{
+ u64 delivered, reference;
+ unsigned int status;
+ /*
+ * If this platform has a PCCT, then
+ * send a command to the platform to update
+ * all PCC registers.
+ */
+ if (comm_base_addr) {
+ pr_debug("Sending PCC READ to update COMM space\n");
+ status = send_pcc_cmd(PCC_CMD_READ, 0, pcc_subspace_idx,
+ comm_base_addr);
+
+ if (!(status & PCC_CMD_COMPLETE)) {
+ pr_err("Err updating PCC comm space\n");
+ return;
+ }
+ }
+
+ reference = cppc_func_ops->get_ref_perf_ctr(cpu);
+ delivered = cppc_func_ops->get_delivered_ctr(cpu);
+
+ delivered = delivered >> FRAC_BITS;
+ reference = reference >> FRAC_BITS;
+
+ cpu->last_sample_time = cpu->sample.time;
+ cpu->sample.time = ktime_get();
+ cpu->sample.delivered = delivered;
+ cpu->sample.reference = reference;
+ cpu->sample.delivered -= cpu->prev_delivered;
+ cpu->sample.reference -= cpu->prev_reference;
+
+ pstate_calc_busy(cpu);
+
+ cpu->prev_delivered = delivered;
+ cpu->prev_reference = reference;
+}
+
+static inline int32_t pstate_get_scaled_busy(struct cpudata *cpu)
+{
+ int32_t core_busy, max_pstate, current_pstate, sample_ratio;
+ u32 duration_us;
+ u32 sample_time;
+
+ 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));
+
+ sample_time = (pid_params.sample_rate_ms * USEC_PER_MSEC);
+ duration_us = (u32) ktime_us_delta(cpu->sample.time,
+ cpu->last_sample_time);
+ if (duration_us > sample_time * 3) {
+ sample_ratio = div_fp(int_tofp(sample_time),
+ int_tofp(duration_us));
+ core_busy = mul_fp(core_busy, sample_ratio);
+ }
+
+ return core_busy;
+}
+
+static inline void pstate_set_sample_time(struct cpudata *cpu)
+{
+ int sample_time, delay;
+
+ sample_time = pid_params.sample_rate_ms;
+ delay = msecs_to_jiffies(sample_time);
+ mod_timer_pinned(&cpu->timer, jiffies + delay);
+}
+
+static void pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
+{
+ int max_perf = cpu->pstate.max_pstate;
+ int max_perf_adj;
+ int min_perf;
+
+ 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.max_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 set_pstate(struct cpudata *cpu, int pstate)
+{
+ int max_perf, min_perf;
+ unsigned int status;
+
+ pstate_get_min_max(cpu, &min_perf, &max_perf);
+
+ pstate = clamp_t(int, pstate, min_perf, max_perf);
+
+ if (pstate == cpu->pstate.current_pstate)
+ return;
+
+ trace_cpu_frequency(pstate * 100000, cpu->cpu);
+
+ cpu->pstate.current_pstate = pstate;
+
+ cppc_func_ops->set_desired_perf(cpu, pstate);
+
+ /*
+ * Send a Write command to tell the platform that
+ * there is new data in the PCC registers.
+ */
+ if (comm_base_addr) {
+ pr_debug("Sending PCC WRITE to update COMM space\n");
+ status = send_pcc_cmd(PCC_CMD_WRITE, 0, pcc_subspace_idx,
+ comm_base_addr);
+
+ if (!(status & PCC_CMD_COMPLETE)) {
+ pr_err("Err updating PCC comm space\n");
+ return;
+ }
+ }
+}
+
+static inline void pstate_pstate_increase(struct cpudata *cpu, int steps)
+{
+ int target;
+ target = cpu->pstate.current_pstate + steps;
+
+ set_pstate(cpu, target);
+}
+
+static inline void pstate_pstate_decrease(struct cpudata *cpu, int steps)
+{
+ int target;
+ target = cpu->pstate.current_pstate - steps;
+ set_pstate(cpu, target);
+}
+
+static inline void pstate_adjust_busy_pstate(struct cpudata *cpu)
+{
+ int32_t busy_scaled;
+ struct _pid *pid;
+ signed int ctl = 0;
+ int steps;
+
+ pid = &cpu->pid;
+ busy_scaled = pstate_get_scaled_busy(cpu);
+
+ ctl = pid_calc(pid, busy_scaled);
+
+ steps = abs(ctl);
+
+ if (ctl < 0)
+ pstate_pstate_increase(cpu, steps);
+ else
+ pstate_pstate_decrease(cpu, steps);
+}
+
+static void pstate_timer_func(unsigned long __data)
+{
+ struct cpudata *cpu = (struct cpudata *) __data;
+ struct sample *sample;
+
+ pstate_sample(cpu);
+
+ sample = &cpu->sample;
+
+ pstate_adjust_busy_pstate(cpu);
+
+ trace_pstate_sample(fp_toint(sample->core_pct_busy),
+ fp_toint(pstate_get_scaled_busy(cpu)),
+ cpu->pstate.current_pstate,
+ sample->reference,
+ sample->delivered,
+ sample->freq);
+
+ pstate_set_sample_time(cpu);
+}
+
+static int cppc_cpufreq_init(struct cpufreq_policy *policy)
+{
+ struct cpudata *cpu;
+ unsigned int cpunum = policy->cpu;
+ unsigned int status;
+ struct cpc_desc *current_cpu_cpc = per_cpu(cpc_desc_ptr, cpunum);
+
+ all_cpu_data[cpunum] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
+ if (!all_cpu_data[cpunum])
+ return -ENOMEM;
+
+ cpu = all_cpu_data[cpunum];
+
+ cpu->cpu = cpunum;
+
+ if (!cppc_func_ops) {
+ pr_err("CPPC is not supported on this platform\n");
+ return -ENOTSUPP;
+ }
+
+ if (!current_cpu_cpc) {
+ pr_err("Undefined CPC descriptor for CPU:%d\n", cpunum);
+ return -ENODEV;
+ }
+
+ /*
+ * If this platform has a PCCT, then
+ * send a command to the platform to update
+ * all PCC registers.
+ */
+ if (comm_base_addr) {
+ pr_debug("Sending PCC READ to update COMM space\n");
+ status = send_pcc_cmd(PCC_CMD_READ, 0, pcc_subspace_idx,
+ comm_base_addr);
+
+ if (!(status & PCC_CMD_COMPLETE)) {
+ pr_err("Err updating PCC comm space\n");
+ return -EIO;
+ }
+ }
+
+ cpu->cpc_desc = current_cpu_cpc;
+ cpu->pcc_comm_address = comm_base_addr;
+ cpu->pstate.min_pstate = cppc_func_ops->get_lowest_perf(cpu);
+ cpu->pstate.max_pstate = cppc_func_ops->get_highest_perf(cpu);
+ /* PCC reads/writes are made to offsets from this base address.*/
+
+ set_pstate(cpu, cpu->pstate.min_pstate);
+
+ init_timer_deferrable(&cpu->timer);
+ cpu->timer.function = pstate_timer_func;
+ cpu->timer.data =
+ (unsigned long)cpu;
+ cpu->timer.expires = jiffies + HZ/100;
+ pstate_busy_pid_reset(cpu);
+ pstate_sample(cpu);
+
+ add_timer_on(&cpu->timer, cpunum);
+
+ pr_info("CPPC PID pstate controlling: cpu %d\n", cpunum);
+
+ if (limits.min_perf_pct == 100 && limits.max_perf_pct == 100)
+ policy->policy = CPUFREQ_POLICY_PERFORMANCE;
+ else
+ policy->policy = CPUFREQ_POLICY_POWERSAVE;
+
+ policy->min = cpu->pstate.min_pstate * 100000;
+ policy->max = cpu->pstate.max_pstate * 100000;
+
+ /* cpuinfo and default policy values */
+ policy->cpuinfo.min_freq = cpu->pstate.min_pstate * 100000;
+ policy->cpuinfo.max_freq = cpu->pstate.max_pstate * 100000;
+ policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+ cpumask_set_cpu(policy->cpu, policy->cpus);
+
+ return 0;
+}
+
+static void cppc_stop_cpu(struct cpufreq_policy *policy)
+{
+ int cpu_num = policy->cpu;
+ struct cpudata *cpu = all_cpu_data[cpu_num];
+
+ pr_info("CPPC PID controller CPU %d exiting\n", cpu_num);
+
+ del_timer_sync(&all_cpu_data[cpu_num]->timer);
+ set_pstate(cpu, cpu->pstate.min_pstate);
+ kfree(all_cpu_data[cpu_num]);
+ all_cpu_data[cpu_num] = NULL;
+ kfree(cpu->cpc_desc);
+}
+
+static int cppc_verify_policy(struct cpufreq_policy *policy)
+{
+ cpufreq_verify_within_cpu_limits(policy);
+
+ if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
+ (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int cppc_set_policy(struct cpufreq_policy *policy)
+{
+ struct cpudata *cpu;
+
+ cpu = all_cpu_data[policy->cpu];
+
+ if (!policy->cpuinfo.max_freq)
+ return -ENODEV;
+
+ if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ limits.min_perf_pct = 100;
+ limits.min_perf = int_tofp(1);
+ limits.max_perf_pct = 100;
+ limits.max_perf = int_tofp(1);
+ return 0;
+ }
+ limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
+ limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
+ limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
+
+ limits.max_policy_pct = policy->max * 100 / policy->cpuinfo.max_freq;
+ limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100);
+ limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
+ limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+
+ return 0;
+}
+
+static unsigned int cppc_get(unsigned int cpu_num)
+{
+ struct sample *sample;
+ struct cpudata *cpu;
+
+ cpu = all_cpu_data[cpu_num];
+ if (!cpu)
+ return 0;
+ sample = &cpu->sample;
+ return sample->freq;
+}
+
+static struct cpufreq_driver cppc_cpufreq = {
+ .flags = CPUFREQ_CONST_LOOPS,
+ .verify = cppc_verify_policy,
+ .setpolicy = cppc_set_policy,
+ .get = cppc_get,
+ .init = cppc_cpufreq_init,
+ .stop_cpu = cppc_stop_cpu,
+ .name = "cppc_cpufreq",
+};
+
+static int cppc_processor_probe(void)
+{
+ struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+ union acpi_object *out_obj, *cpc_obj;
+ struct cpc_desc *current_cpu_cpc;
+ struct cpc_register_resource *gas_t;
+ char proc_name[11];
+ unsigned int num_ent, ret = 0, i, cpu, len;
+ acpi_handle handle;
+ acpi_status status;
+
+ /*Parse the ACPI _CPC table for each CPU. */
+ for_each_online_cpu(cpu) {
+ sprintf(proc_name, "\\_PR.CPU%d", cpu);
+
+ status = acpi_get_handle(NULL, proc_name, &handle);
+ if (ACPI_FAILURE(status)) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ if (!acpi_has_method(handle, "_CPC")) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ status = acpi_evaluate_object(handle, "_CPC", NULL, &output);
+ if (ACPI_FAILURE(status)) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ out_obj = (union acpi_object *) output.pointer;
+ if (out_obj->type != ACPI_TYPE_PACKAGE) {
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ current_cpu_cpc = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
+ if (!current_cpu_cpc) {
+ pr_err("Could not allocate per cpu CPC descriptors\n");
+ return -ENOMEM;
+ }
+ num_ent = out_obj->package.count;
+ current_cpu_cpc->num_entries = num_ent;
+
+ pr_debug("num_ent in CPC table:%d\n", num_ent);
+
+ /* Iterate through each entry in _CPC */
+ for (i = 2; i < num_ent; i++) {
+ cpc_obj = &out_obj->package.elements[i];
+
+ if (cpc_obj->type != ACPI_TYPE_BUFFER) {
+ pr_err("Malformed PCC entry in CPC table\n");
+ ret = -EINVAL;
+ goto out_free;
+ }
+
+ gas_t = (struct cpc_register_resource *) cpc_obj->buffer.pointer;
+
+ if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
+ if (pcc_subspace_idx < 0)
+ pcc_subspace_idx = gas_t->access_width;
+ }
+
+ current_cpu_cpc->cpc_regs[i-2] = (struct cpc_register_resource) {
+ .space_id = gas_t->space_id,
+ .length = gas_t->length,
+ .bit_width = gas_t->bit_width,
+ .bit_offset = gas_t->bit_offset,
+ .address = gas_t->address,
+ .access_width = gas_t->access_width,
+ };
+ }
+ per_cpu(cpc_desc_ptr, cpu) = current_cpu_cpc;
+ }
+
+ pr_debug("Completed parsing , now onto PCC init\n");
+
+ if (pcc_subspace_idx >= 0) {
+ ret = get_pcc_comm_channel(pcc_subspace_idx, &pcc_comm_base_addr, &len);
+ if (ret) {
+ pr_err("No PCC Communication Channel found\n");
+ ret = -ENODEV;
+ goto out_free;
+ }
+
+ //XXX: PCC HACK: The PCC hack in drivers/acpi/pcc.c just
+ //returns a kmallocd address, so no point in ioremapping
+ //it here. Instead we'll just use it directly.
+ //Normally, we'd ioremap the address specified in the PCCT
+ //header for this PCC subspace.
+
+ comm_base_addr = &pcc_comm_base_addr;
+
+ // comm_base_addr = ioremap_nocache(pcc_comm_base_addr, len);
+
+ // if (!comm_base_addr) {
+ // pr_err("ioremapping pcc comm space failed\n");
+ // ret = -ENOMEM;
+ // goto out_free;
+ // }
+ pr_debug("PCC ioremapd space:%p, PCCT addr: %lld\n", comm_base_addr, pcc_comm_base_addr);
+
+ } else {
+ pr_err("No PCC subspace detected in any CPC structure!\n");
+ ret = -EINVAL;
+ goto out_free;
+ }
+
+ /* Everything looks okay */
+ pr_info("Successfully parsed all CPC structs\n");
+ pr_debug("Enable CPPC_EN\n");
+ /*XXX: Send write cmd to enable CPPC */
+
+ kfree(output.pointer);
+ return 0;
+
+out_free:
+ for_each_online_cpu(cpu) {
+ current_cpu_cpc = per_cpu(cpc_desc_ptr, cpu);
+ if (current_cpu_cpc)
+ kfree(current_cpu_cpc);
+ }
+
+ kfree(output.pointer);
+ return -ENODEV;
+}
+
+static void 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 int __init cppc_init(void)
+{
+ int ret = 0;
+ unsigned int cpu;
+
+ /*
+ * Platform specific low level accessors should be
+ * initialized by now if CPPC is supported.
+ */
+ if (!cppc_func_ops) {
+ pr_err("No CPPC low level accessors found\n");
+ return -ENODEV;
+ }
+
+ if(acpi_disabled || cppc_processor_probe()) {
+ pr_err("Err initializing CPC structures or ACPI is disabled\n");
+ return -ENODEV;
+ }
+
+ copy_pid_params(&cppc_func_ops->pid_policy);
+
+ pr_info("CPPC PID driver initializing.\n");
+
+ all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus());
+ if (!all_cpu_data)
+ return -ENOMEM;
+
+ /* Now register with CPUfreq */
+ ret = cpufreq_register_driver(&cppc_cpufreq);
+ if (ret)
+ goto out;
+
+ cppc_pstate_debug_expose_params();
+ cppc_pstate_sysfs_expose_params();
+
+ return ret;
+
+out:
+ get_online_cpus();
+ for_each_online_cpu(cpu) {
+ if (all_cpu_data[cpu]) {
+ del_timer_sync(&all_cpu_data[cpu]->timer);
+ kfree(all_cpu_data[cpu]);
+ }
+ }
+
+ put_online_cpus();
+ vfree(all_cpu_data);
+ return -ENODEV;
+}
+device_initcall(cppc_init);
diff --git a/drivers/cpufreq/cppc.h b/drivers/cpufreq/cppc.h
new file mode 100644
index 0000000..3adbd3d
--- /dev/null
+++ b/drivers/cpufreq/cppc.h
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
+ *
+ * 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.
+ *
+ * PID algo bits are from intel_pstate.c and modified to use CPPC
+ * accessors.
+ *
+ */
+
+#ifndef _CPPC_H
+#define _CPPC_H
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/ktime.h>
+#include <linux/hrtimer.h>
+/*
+ * The max number of Register entries
+ * in the CPC table
+ */
+#define MAX_CPC_REG_ENT 19
+
+/* These are indexes into the per-cpu cpc_regs[]. Order is important. */
+enum cppc_pcc_regs {
+ HIGHEST_PERF, /* Highest Performance */
+ NOMINAL_PERF, /* Nominal Performance */
+ LOW_NON_LINEAR_PERF, /* Lowest Nonlinear Performance */
+ LOWEST_PERF, /* Lowest Performance */
+ GUARANTEED_PERF, /* Guaranteed Performance Register */
+ DESIRED_PERF, /* Desired Performance Register */
+ MIN_PERF, /* Minimum Performance Register */
+ MAX_PERF, /* Maximum Performance Register */
+ PERF_REDUC_TOLERANCE, /* Performance Reduction Tolerance Register */
+ TIME_WINDOW, /* Time Window Register */
+ CTR_WRAP_TIME, /* Counter Wraparound Time */
+ REFERENCE_CTR, /* Reference Counter Register */
+ DELIVERED_CTR, /* Delivered Counter Register */
+ PERF_LIMITED, /* Performance Limited Register */
+ ENABLE, /* Enable Register */
+ AUTO_SEL_ENABLE, /* Autonomous Selection Enable */
+ AUTO_ACT_WINDOW, /* Autonomous Activity Window */
+ ENERGY_PERF, /* Energy Performance Preference Register */
+ REFERENCE_PERF, /* Reference Performance */
+};
+
+/* Each register in the CPC table has the following format */
+struct cpc_register_resource {
+ u8 descriptor;
+ u16 length;
+ u8 space_id;
+ u8 bit_width;
+ u8 bit_offset;
+ u8 access_width;
+ u64 __iomem address;
+} __attribute__ ((packed));
+
+struct cpc_desc {
+ unsigned int num_entries;
+ unsigned int version;
+ struct cpc_register_resource cpc_regs[MAX_CPC_REG_ENT];
+};
+
+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 sample {
+ int32_t core_pct_busy;
+ u64 delivered;
+ u64 reference;
+ int freq;
+ ktime_t time;
+};
+
+struct pstate_data {
+ int current_pstate;
+ int min_pstate;
+ int max_pstate;
+};
+
+struct cpudata {
+ int cpu;
+
+ struct timer_list timer;
+
+ struct pstate_data pstate;
+ struct _pid pid;
+
+ ktime_t last_sample_time;
+ u64 prev_delivered;
+ u64 prev_reference;
+ struct sample sample;
+ struct cpc_desc *cpc_desc;
+ void __iomem *pcc_comm_address;
+};
+
+struct perf_limits {
+ int max_perf_pct;
+ int min_perf_pct;
+ int32_t max_perf;
+ int32_t min_perf;
+ int max_policy_pct;
+ int max_sysfs_pct;
+};
+
+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 cpc_funcs {
+ struct pstate_adjust_policy pid_policy;
+
+ u32 (*get_highest_perf)(struct cpudata *);
+ u32 (*get_nominal_perf)(struct cpudata *);
+ u64 (*get_ref_perf_ctr)(struct cpudata *);
+ u32 (*get_lowest_nonlinear_perf)(struct cpudata *);
+ u32 (*get_lowest_perf)(struct cpudata *);
+ u32 (*get_guaranteed_perf)(struct cpudata *);
+
+ u32 (*get_desired_perf)(struct cpudata *);
+ void (*set_desired_perf)(struct cpudata *, u32 val);
+
+ u64 (*get_delivered_ctr)(struct cpudata *);
+
+ /* Optional */
+ u32 (*get_max_perf)(struct cpudata *);
+ void (*set_max_perf)(struct cpudata *, u32 val);
+
+ u32 (*get_min_perf)(struct cpudata *);
+ void (*set_min_perf)(struct cpudata *, u32 val);
+
+ u32 (*get_perf_reduc)(struct cpudata *);
+ void (*set_perf_reduc)(struct cpudata *, u32 val);
+
+ u32 (*get_time_window)(struct cpudata *);
+ void (*set_time_window)(struct cpudata *, u32 msecs);
+
+ u64 (*get_ctr_wraparound)(struct cpudata *);
+ void (*set_ctr_wraparound)(struct cpudata *, u32 secs);
+
+ u8 (*get_perf_limit)(struct cpudata *);
+ void (*set_perf_limit)(struct cpudata *);
+
+ void (*set_cppc_enable)(struct cpudata *);
+
+ u8 (*get_auto_sel_en)(struct cpudata *);
+ void (*set_auto_sel_en)(struct cpudata *);
+
+ void (*set_auto_activity)(struct cpudata *, u32 val);
+
+ void (*set_energy_pref)(struct cpudata *, u32 val);
+
+ u32 (*get_ref_perf_rate)(struct cpudata *);
+};
+
+extern struct cpc_funcs *cppc_func_ops;
+extern u64 cpc_read64(struct cpc_register_resource *reg);
+extern int cpc_write64(u64 val, struct cpc_register_resource *reg);
+
+#endif /* _CPPC_H */
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/