linux/drivers/cpufreq/scpi-cpufreq.c
Yangtao Li d5aa35fcf3 cpufreq: scpi: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2023-07-20 16:02:12 +05:30

230 lines
5.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* System Control and Power Interface (SCPI) based CPUFreq Interface driver
*
* Copyright (C) 2015 ARM Ltd.
* Sudeep Holla <sudeep.holla@arm.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/scpi_protocol.h>
#include <linux/slab.h>
#include <linux/types.h>
struct scpi_data {
struct clk *clk;
struct device *cpu_dev;
};
static struct scpi_ops *scpi_ops;
static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
struct scpi_data *priv = policy->driver_data;
unsigned long rate = clk_get_rate(priv->clk);
return rate / 1000;
}
static int
scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
{
u64 rate = policy->freq_table[index].frequency * 1000;
struct scpi_data *priv = policy->driver_data;
int ret;
ret = clk_set_rate(priv->clk, rate);
if (ret)
return ret;
if (clk_get_rate(priv->clk) != rate)
return -EIO;
return 0;
}
static int
scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
{
int cpu, domain, tdomain;
struct device *tcpu_dev;
domain = scpi_ops->device_domain_id(cpu_dev);
if (domain < 0)
return domain;
for_each_possible_cpu(cpu) {
if (cpu == cpu_dev->id)
continue;
tcpu_dev = get_cpu_device(cpu);
if (!tcpu_dev)
continue;
tdomain = scpi_ops->device_domain_id(tcpu_dev);
if (tdomain == domain)
cpumask_set_cpu(cpu, cpumask);
}
return 0;
}
static int scpi_cpufreq_init(struct cpufreq_policy *policy)
{
int ret;
unsigned int latency;
struct device *cpu_dev;
struct scpi_data *priv;
struct cpufreq_frequency_table *freq_table;
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
pr_err("failed to get cpu%d device\n", policy->cpu);
return -ENODEV;
}
ret = scpi_ops->add_opps_to_device(cpu_dev);
if (ret) {
dev_warn(cpu_dev, "failed to add opps to the device\n");
return ret;
}
ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
if (ret) {
dev_warn(cpu_dev, "failed to get sharing cpumask\n");
return ret;
}
ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
if (ret) {
dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
__func__, ret);
return ret;
}
ret = dev_pm_opp_get_opp_count(cpu_dev);
if (ret <= 0) {
dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
ret = -EPROBE_DEFER;
goto out_free_opp;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out_free_opp;
}
ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
if (ret) {
dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
goto out_free_priv;
}
priv->cpu_dev = cpu_dev;
priv->clk = clk_get(cpu_dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
__func__, cpu_dev->id);
ret = PTR_ERR(priv->clk);
goto out_free_cpufreq_table;
}
policy->driver_data = priv;
policy->freq_table = freq_table;
/* scpi allows DVFS request for any domain from any CPU */
policy->dvfs_possible_from_any_cpu = true;
latency = scpi_ops->get_transition_latency(cpu_dev);
if (!latency)
latency = CPUFREQ_ETERNAL;
policy->cpuinfo.transition_latency = latency;
policy->fast_switch_possible = false;
return 0;
out_free_cpufreq_table:
dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
out_free_priv:
kfree(priv);
out_free_opp:
dev_pm_opp_remove_all_dynamic(cpu_dev);
return ret;
}
static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
{
struct scpi_data *priv = policy->driver_data;
clk_put(priv->clk);
dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
kfree(priv);
return 0;
}
static struct cpufreq_driver scpi_cpufreq_driver = {
.name = "scpi-cpufreq",
.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
CPUFREQ_NEED_INITIAL_FREQ_CHECK |
CPUFREQ_IS_COOLING_DEV,
.verify = cpufreq_generic_frequency_table_verify,
.attr = cpufreq_generic_attr,
.get = scpi_cpufreq_get_rate,
.init = scpi_cpufreq_init,
.exit = scpi_cpufreq_exit,
.target_index = scpi_cpufreq_set_target,
.register_em = cpufreq_register_em_with_opp,
};
static int scpi_cpufreq_probe(struct platform_device *pdev)
{
int ret;
scpi_ops = get_scpi_ops();
if (!scpi_ops)
return -EIO;
ret = cpufreq_register_driver(&scpi_cpufreq_driver);
if (ret)
dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
__func__, ret);
return ret;
}
static void scpi_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&scpi_cpufreq_driver);
scpi_ops = NULL;
}
static struct platform_driver scpi_cpufreq_platdrv = {
.driver = {
.name = "scpi-cpufreq",
},
.probe = scpi_cpufreq_probe,
.remove_new = scpi_cpufreq_remove,
};
module_platform_driver(scpi_cpufreq_platdrv);
MODULE_ALIAS("platform:scpi-cpufreq");
MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
MODULE_LICENSE("GPL v2");