linux/drivers/cpufreq/mt8173-cpufreq.c
Viresh Kumar 8a31d9d942 PM / OPP: Update OPP users to put reference
This patch updates dev_pm_opp_find_freq_*() routines to get a reference
to the OPPs returned by them.

Also updates the users of dev_pm_opp_find_freq_*() routines to call
dev_pm_opp_put() after they are done using the OPPs.

As it is guaranteed the that OPPs wouldn't get freed while being used,
the RCU read side locking present with the users isn't required anymore.
Drop it as well.

This patch also updates all users of devfreq_recommended_opp() which was
returning an OPP received from the OPP core.

Note that some of the OPP core routines have gained
rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs
within them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [Devfreq]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-01-30 09:22:21 +01:00

603 lines
16 KiB
C

/*
* Copyright (c) 2015 Linaro Ltd.
* Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpu_cooling.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#define MIN_VOLT_SHIFT (100000)
#define MAX_VOLT_SHIFT (200000)
#define MAX_VOLT_LIMIT (1150000)
#define VOLT_TOL (10000)
/*
* The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
* on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
* Mediatek SoCs has two voltage inputs, Vproc and Vsram. In some cases the two
* voltage inputs need to be controlled under a hardware limitation:
* 100mV < Vsram - Vproc < 200mV
*
* When scaling the clock frequency of a CPU clock domain, the clock source
* needs to be switched to another stable PLL clock temporarily until
* the original PLL becomes stable at target frequency.
*/
struct mtk_cpu_dvfs_info {
struct cpumask cpus;
struct device *cpu_dev;
struct regulator *proc_reg;
struct regulator *sram_reg;
struct clk *cpu_clk;
struct clk *inter_clk;
struct thermal_cooling_device *cdev;
struct list_head list_head;
int intermediate_voltage;
bool need_voltage_tracking;
};
static LIST_HEAD(dvfs_info_list);
static struct mtk_cpu_dvfs_info *mtk_cpu_dvfs_info_lookup(int cpu)
{
struct mtk_cpu_dvfs_info *info;
list_for_each_entry(info, &dvfs_info_list, list_head) {
if (cpumask_test_cpu(cpu, &info->cpus))
return info;
}
return NULL;
}
static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
int new_vproc)
{
struct regulator *proc_reg = info->proc_reg;
struct regulator *sram_reg = info->sram_reg;
int old_vproc, old_vsram, new_vsram, vsram, vproc, ret;
old_vproc = regulator_get_voltage(proc_reg);
if (old_vproc < 0) {
pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
return old_vproc;
}
/* Vsram should not exceed the maximum allowed voltage of SoC. */
new_vsram = min(new_vproc + MIN_VOLT_SHIFT, MAX_VOLT_LIMIT);
if (old_vproc < new_vproc) {
/*
* When scaling up voltages, Vsram and Vproc scale up step
* by step. At each step, set Vsram to (Vproc + 200mV) first,
* then set Vproc to (Vsram - 100mV).
* Keep doing it until Vsram and Vproc hit target voltages.
*/
do {
old_vsram = regulator_get_voltage(sram_reg);
if (old_vsram < 0) {
pr_err("%s: invalid Vsram value: %d\n",
__func__, old_vsram);
return old_vsram;
}
old_vproc = regulator_get_voltage(proc_reg);
if (old_vproc < 0) {
pr_err("%s: invalid Vproc value: %d\n",
__func__, old_vproc);
return old_vproc;
}
vsram = min(new_vsram, old_vproc + MAX_VOLT_SHIFT);
if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
vsram = MAX_VOLT_LIMIT;
/*
* If the target Vsram hits the maximum voltage,
* try to set the exact voltage value first.
*/
ret = regulator_set_voltage(sram_reg, vsram,
vsram);
if (ret)
ret = regulator_set_voltage(sram_reg,
vsram - VOLT_TOL,
vsram);
vproc = new_vproc;
} else {
ret = regulator_set_voltage(sram_reg, vsram,
vsram + VOLT_TOL);
vproc = vsram - MIN_VOLT_SHIFT;
}
if (ret)
return ret;
ret = regulator_set_voltage(proc_reg, vproc,
vproc + VOLT_TOL);
if (ret) {
regulator_set_voltage(sram_reg, old_vsram,
old_vsram);
return ret;
}
} while (vproc < new_vproc || vsram < new_vsram);
} else if (old_vproc > new_vproc) {
/*
* When scaling down voltages, Vsram and Vproc scale down step
* by step. At each step, set Vproc to (Vsram - 200mV) first,
* then set Vproc to (Vproc + 100mV).
* Keep doing it until Vsram and Vproc hit target voltages.
*/
do {
old_vproc = regulator_get_voltage(proc_reg);
if (old_vproc < 0) {
pr_err("%s: invalid Vproc value: %d\n",
__func__, old_vproc);
return old_vproc;
}
old_vsram = regulator_get_voltage(sram_reg);
if (old_vsram < 0) {
pr_err("%s: invalid Vsram value: %d\n",
__func__, old_vsram);
return old_vsram;
}
vproc = max(new_vproc, old_vsram - MAX_VOLT_SHIFT);
ret = regulator_set_voltage(proc_reg, vproc,
vproc + VOLT_TOL);
if (ret)
return ret;
if (vproc == new_vproc)
vsram = new_vsram;
else
vsram = max(new_vsram, vproc + MIN_VOLT_SHIFT);
if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
vsram = MAX_VOLT_LIMIT;
/*
* If the target Vsram hits the maximum voltage,
* try to set the exact voltage value first.
*/
ret = regulator_set_voltage(sram_reg, vsram,
vsram);
if (ret)
ret = regulator_set_voltage(sram_reg,
vsram - VOLT_TOL,
vsram);
} else {
ret = regulator_set_voltage(sram_reg, vsram,
vsram + VOLT_TOL);
}
if (ret) {
regulator_set_voltage(proc_reg, old_vproc,
old_vproc);
return ret;
}
} while (vproc > new_vproc + VOLT_TOL ||
vsram > new_vsram + VOLT_TOL);
}
return 0;
}
static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
{
if (info->need_voltage_tracking)
return mtk_cpufreq_voltage_tracking(info, vproc);
else
return regulator_set_voltage(info->proc_reg, vproc,
vproc + VOLT_TOL);
}
static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int index)
{
struct cpufreq_frequency_table *freq_table = policy->freq_table;
struct clk *cpu_clk = policy->clk;
struct clk *armpll = clk_get_parent(cpu_clk);
struct mtk_cpu_dvfs_info *info = policy->driver_data;
struct device *cpu_dev = info->cpu_dev;
struct dev_pm_opp *opp;
long freq_hz, old_freq_hz;
int vproc, old_vproc, inter_vproc, target_vproc, ret;
inter_vproc = info->intermediate_voltage;
old_freq_hz = clk_get_rate(cpu_clk);
old_vproc = regulator_get_voltage(info->proc_reg);
if (old_vproc < 0) {
pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
return old_vproc;
}
freq_hz = freq_table[index].frequency * 1000;
opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
if (IS_ERR(opp)) {
pr_err("cpu%d: failed to find OPP for %ld\n",
policy->cpu, freq_hz);
return PTR_ERR(opp);
}
vproc = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
/*
* If the new voltage or the intermediate voltage is higher than the
* current voltage, scale up voltage first.
*/
target_vproc = (inter_vproc > vproc) ? inter_vproc : vproc;
if (old_vproc < target_vproc) {
ret = mtk_cpufreq_set_voltage(info, target_vproc);
if (ret) {
pr_err("cpu%d: failed to scale up voltage!\n",
policy->cpu);
mtk_cpufreq_set_voltage(info, old_vproc);
return ret;
}
}
/* Reparent the CPU clock to intermediate clock. */
ret = clk_set_parent(cpu_clk, info->inter_clk);
if (ret) {
pr_err("cpu%d: failed to re-parent cpu clock!\n",
policy->cpu);
mtk_cpufreq_set_voltage(info, old_vproc);
WARN_ON(1);
return ret;
}
/* Set the original PLL to target rate. */
ret = clk_set_rate(armpll, freq_hz);
if (ret) {
pr_err("cpu%d: failed to scale cpu clock rate!\n",
policy->cpu);
clk_set_parent(cpu_clk, armpll);
mtk_cpufreq_set_voltage(info, old_vproc);
return ret;
}
/* Set parent of CPU clock back to the original PLL. */
ret = clk_set_parent(cpu_clk, armpll);
if (ret) {
pr_err("cpu%d: failed to re-parent cpu clock!\n",
policy->cpu);
mtk_cpufreq_set_voltage(info, inter_vproc);
WARN_ON(1);
return ret;
}
/*
* If the new voltage is lower than the intermediate voltage or the
* original voltage, scale down to the new voltage.
*/
if (vproc < inter_vproc || vproc < old_vproc) {
ret = mtk_cpufreq_set_voltage(info, vproc);
if (ret) {
pr_err("cpu%d: failed to scale down voltage!\n",
policy->cpu);
clk_set_parent(cpu_clk, info->inter_clk);
clk_set_rate(armpll, old_freq_hz);
clk_set_parent(cpu_clk, armpll);
return ret;
}
}
return 0;
}
#define DYNAMIC_POWER "dynamic-power-coefficient"
static void mtk_cpufreq_ready(struct cpufreq_policy *policy)
{
struct mtk_cpu_dvfs_info *info = policy->driver_data;
struct device_node *np = of_node_get(info->cpu_dev->of_node);
u32 capacitance = 0;
if (WARN_ON(!np))
return;
if (of_find_property(np, "#cooling-cells", NULL)) {
of_property_read_u32(np, DYNAMIC_POWER, &capacitance);
info->cdev = of_cpufreq_power_cooling_register(np,
policy->related_cpus,
capacitance,
NULL);
if (IS_ERR(info->cdev)) {
dev_err(info->cpu_dev,
"running cpufreq without cooling device: %ld\n",
PTR_ERR(info->cdev));
info->cdev = NULL;
}
}
of_node_put(np);
}
static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
{
struct device *cpu_dev;
struct regulator *proc_reg = ERR_PTR(-ENODEV);
struct regulator *sram_reg = ERR_PTR(-ENODEV);
struct clk *cpu_clk = ERR_PTR(-ENODEV);
struct clk *inter_clk = ERR_PTR(-ENODEV);
struct dev_pm_opp *opp;
unsigned long rate;
int ret;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("failed to get cpu%d device\n", cpu);
return -ENODEV;
}
cpu_clk = clk_get(cpu_dev, "cpu");
if (IS_ERR(cpu_clk)) {
if (PTR_ERR(cpu_clk) == -EPROBE_DEFER)
pr_warn("cpu clk for cpu%d not ready, retry.\n", cpu);
else
pr_err("failed to get cpu clk for cpu%d\n", cpu);
ret = PTR_ERR(cpu_clk);
return ret;
}
inter_clk = clk_get(cpu_dev, "intermediate");
if (IS_ERR(inter_clk)) {
if (PTR_ERR(inter_clk) == -EPROBE_DEFER)
pr_warn("intermediate clk for cpu%d not ready, retry.\n",
cpu);
else
pr_err("failed to get intermediate clk for cpu%d\n",
cpu);
ret = PTR_ERR(inter_clk);
goto out_free_resources;
}
proc_reg = regulator_get_exclusive(cpu_dev, "proc");
if (IS_ERR(proc_reg)) {
if (PTR_ERR(proc_reg) == -EPROBE_DEFER)
pr_warn("proc regulator for cpu%d not ready, retry.\n",
cpu);
else
pr_err("failed to get proc regulator for cpu%d\n",
cpu);
ret = PTR_ERR(proc_reg);
goto out_free_resources;
}
/* Both presence and absence of sram regulator are valid cases. */
sram_reg = regulator_get_exclusive(cpu_dev, "sram");
/* Get OPP-sharing information from "operating-points-v2" bindings */
ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, &info->cpus);
if (ret) {
pr_err("failed to get OPP-sharing information for cpu%d\n",
cpu);
goto out_free_resources;
}
ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
if (ret) {
pr_warn("no OPP table for cpu%d\n", cpu);
goto out_free_resources;
}
/* Search a safe voltage for intermediate frequency. */
rate = clk_get_rate(inter_clk);
opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
if (IS_ERR(opp)) {
pr_err("failed to get intermediate opp for cpu%d\n", cpu);
ret = PTR_ERR(opp);
goto out_free_opp_table;
}
info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
info->cpu_dev = cpu_dev;
info->proc_reg = proc_reg;
info->sram_reg = IS_ERR(sram_reg) ? NULL : sram_reg;
info->cpu_clk = cpu_clk;
info->inter_clk = inter_clk;
/*
* If SRAM regulator is present, software "voltage tracking" is needed
* for this CPU power domain.
*/
info->need_voltage_tracking = !IS_ERR(sram_reg);
return 0;
out_free_opp_table:
dev_pm_opp_of_cpumask_remove_table(&info->cpus);
out_free_resources:
if (!IS_ERR(proc_reg))
regulator_put(proc_reg);
if (!IS_ERR(sram_reg))
regulator_put(sram_reg);
if (!IS_ERR(cpu_clk))
clk_put(cpu_clk);
if (!IS_ERR(inter_clk))
clk_put(inter_clk);
return ret;
}
static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
{
if (!IS_ERR(info->proc_reg))
regulator_put(info->proc_reg);
if (!IS_ERR(info->sram_reg))
regulator_put(info->sram_reg);
if (!IS_ERR(info->cpu_clk))
clk_put(info->cpu_clk);
if (!IS_ERR(info->inter_clk))
clk_put(info->inter_clk);
dev_pm_opp_of_cpumask_remove_table(&info->cpus);
}
static int mtk_cpufreq_init(struct cpufreq_policy *policy)
{
struct mtk_cpu_dvfs_info *info;
struct cpufreq_frequency_table *freq_table;
int ret;
info = mtk_cpu_dvfs_info_lookup(policy->cpu);
if (!info) {
pr_err("dvfs info for cpu%d is not initialized.\n",
policy->cpu);
return -EINVAL;
}
ret = dev_pm_opp_init_cpufreq_table(info->cpu_dev, &freq_table);
if (ret) {
pr_err("failed to init cpufreq table for cpu%d: %d\n",
policy->cpu, ret);
return ret;
}
ret = cpufreq_table_validate_and_show(policy, freq_table);
if (ret) {
pr_err("%s: invalid frequency table: %d\n", __func__, ret);
goto out_free_cpufreq_table;
}
cpumask_copy(policy->cpus, &info->cpus);
policy->driver_data = info;
policy->clk = info->cpu_clk;
return 0;
out_free_cpufreq_table:
dev_pm_opp_free_cpufreq_table(info->cpu_dev, &freq_table);
return ret;
}
static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
{
struct mtk_cpu_dvfs_info *info = policy->driver_data;
cpufreq_cooling_unregister(info->cdev);
dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
return 0;
}
static struct cpufreq_driver mt8173_cpufreq_driver = {
.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = mtk_cpufreq_set_target,
.get = cpufreq_generic_get,
.init = mtk_cpufreq_init,
.exit = mtk_cpufreq_exit,
.ready = mtk_cpufreq_ready,
.name = "mtk-cpufreq",
.attr = cpufreq_generic_attr,
};
static int mt8173_cpufreq_probe(struct platform_device *pdev)
{
struct mtk_cpu_dvfs_info *info, *tmp;
int cpu, ret;
for_each_possible_cpu(cpu) {
info = mtk_cpu_dvfs_info_lookup(cpu);
if (info)
continue;
info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
if (!info) {
ret = -ENOMEM;
goto release_dvfs_info_list;
}
ret = mtk_cpu_dvfs_info_init(info, cpu);
if (ret) {
dev_err(&pdev->dev,
"failed to initialize dvfs info for cpu%d\n",
cpu);
goto release_dvfs_info_list;
}
list_add(&info->list_head, &dvfs_info_list);
}
ret = cpufreq_register_driver(&mt8173_cpufreq_driver);
if (ret) {
dev_err(&pdev->dev, "failed to register mtk cpufreq driver\n");
goto release_dvfs_info_list;
}
return 0;
release_dvfs_info_list:
list_for_each_entry_safe(info, tmp, &dvfs_info_list, list_head) {
mtk_cpu_dvfs_info_release(info);
list_del(&info->list_head);
}
return ret;
}
static struct platform_driver mt8173_cpufreq_platdrv = {
.driver = {
.name = "mt8173-cpufreq",
},
.probe = mt8173_cpufreq_probe,
};
static int mt8173_cpufreq_driver_init(void)
{
struct platform_device *pdev;
int err;
if (!of_machine_is_compatible("mediatek,mt8173"))
return -ENODEV;
err = platform_driver_register(&mt8173_cpufreq_platdrv);
if (err)
return err;
/*
* Since there's no place to hold device registration code and no
* device tree based way to match cpufreq driver yet, both the driver
* and the device registration codes are put here to handle defer
* probing.
*/
pdev = platform_device_register_simple("mt8173-cpufreq", -1, NULL, 0);
if (IS_ERR(pdev)) {
pr_err("failed to register mtk-cpufreq platform device\n");
return PTR_ERR(pdev);
}
return 0;
}
device_initcall(mt8173_cpufreq_driver_init);