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![Viresh Kumar](/assets/img/avatar_default.png)
Since the commit2a4eb7358a
"OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()", dynamically created OPP aren't automatically removed anymore by dev_pm_opp_cpumask_remove_table(). This affects the scpi and scmi cpufreq drivers which no longer free OPPs on failures or on invocations of the policy->exit() callback. Create a generic OPP helper dev_pm_opp_remove_all_dynamic() which can be called from these drivers instead of dev_pm_opp_cpumask_remove_table(). In dev_pm_opp_remove_all_dynamic(), we need to make sure that the opp_list isn't getting accessed simultaneously from other parts of the OPP core while the helper is freeing dynamic OPPs, i.e. we can't drop the opp_table->lock while traversing through the OPP list. And to accomplish that, this patch also creates _opp_kref_release_unlocked() which can be called from this new helper with the opp_table lock already held. Cc: 4.20 <stable@vger.kernel.org> # v4.20 Reported-by: Valentin Schneider <valentin.schneider@arm.com> Fixes:2a4eb7358a
"OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()" Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
251 lines
5.9 KiB
C
251 lines
5.9 KiB
C
/*
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* System Control and Power Interface (SCPI) based CPUFreq Interface driver
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*
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* It provides necessary ops to arm_big_little cpufreq driver.
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*
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* Copyright (C) 2015 ARM Ltd.
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* Sudeep Holla <sudeep.holla@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_cooling.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/pm_opp.h>
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#include <linux/scpi_protocol.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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struct scpi_data {
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struct clk *clk;
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struct device *cpu_dev;
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struct thermal_cooling_device *cdev;
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};
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static struct scpi_ops *scpi_ops;
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static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
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struct scpi_data *priv = policy->driver_data;
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unsigned long rate = clk_get_rate(priv->clk);
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return rate / 1000;
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}
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static int
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scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
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{
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unsigned long freq = policy->freq_table[index].frequency;
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struct scpi_data *priv = policy->driver_data;
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u64 rate = freq * 1000;
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int ret;
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ret = clk_set_rate(priv->clk, rate);
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if (ret)
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return ret;
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if (clk_get_rate(priv->clk) != rate)
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return -EIO;
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arch_set_freq_scale(policy->related_cpus, freq,
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policy->cpuinfo.max_freq);
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return 0;
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}
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static int
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scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
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{
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int cpu, domain, tdomain;
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struct device *tcpu_dev;
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domain = scpi_ops->device_domain_id(cpu_dev);
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if (domain < 0)
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return domain;
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for_each_possible_cpu(cpu) {
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if (cpu == cpu_dev->id)
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continue;
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tcpu_dev = get_cpu_device(cpu);
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if (!tcpu_dev)
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continue;
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tdomain = scpi_ops->device_domain_id(tcpu_dev);
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if (tdomain == domain)
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cpumask_set_cpu(cpu, cpumask);
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}
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return 0;
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}
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static int scpi_cpufreq_init(struct cpufreq_policy *policy)
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{
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int ret;
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unsigned int latency;
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struct device *cpu_dev;
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struct scpi_data *priv;
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struct cpufreq_frequency_table *freq_table;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("failed to get cpu%d device\n", policy->cpu);
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return -ENODEV;
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}
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ret = scpi_ops->add_opps_to_device(cpu_dev);
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if (ret) {
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dev_warn(cpu_dev, "failed to add opps to the device\n");
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return ret;
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}
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ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_warn(cpu_dev, "failed to get sharing cpumask\n");
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return ret;
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}
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ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
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__func__, ret);
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return ret;
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}
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ret = dev_pm_opp_get_opp_count(cpu_dev);
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if (ret <= 0) {
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dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
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ret = -EPROBE_DEFER;
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goto out_free_opp;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto out_free_opp;
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}
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ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
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if (ret) {
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dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
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goto out_free_priv;
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}
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priv->cpu_dev = cpu_dev;
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priv->clk = clk_get(cpu_dev, NULL);
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if (IS_ERR(priv->clk)) {
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dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
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__func__, cpu_dev->id);
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ret = PTR_ERR(priv->clk);
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goto out_free_cpufreq_table;
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}
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policy->driver_data = priv;
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policy->freq_table = freq_table;
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/* scpi allows DVFS request for any domain from any CPU */
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policy->dvfs_possible_from_any_cpu = true;
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latency = scpi_ops->get_transition_latency(cpu_dev);
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if (!latency)
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latency = CPUFREQ_ETERNAL;
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policy->cpuinfo.transition_latency = latency;
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policy->fast_switch_possible = false;
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return 0;
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out_free_cpufreq_table:
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dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
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out_free_priv:
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kfree(priv);
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out_free_opp:
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dev_pm_opp_remove_all_dynamic(cpu_dev);
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return ret;
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}
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static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct scpi_data *priv = policy->driver_data;
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cpufreq_cooling_unregister(priv->cdev);
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clk_put(priv->clk);
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dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
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kfree(priv);
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dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
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return 0;
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}
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static void scpi_cpufreq_ready(struct cpufreq_policy *policy)
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{
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struct scpi_data *priv = policy->driver_data;
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priv->cdev = of_cpufreq_cooling_register(policy);
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}
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static struct cpufreq_driver scpi_cpufreq_driver = {
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.name = "scpi-cpufreq",
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.flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
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CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.verify = cpufreq_generic_frequency_table_verify,
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.attr = cpufreq_generic_attr,
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.get = scpi_cpufreq_get_rate,
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.init = scpi_cpufreq_init,
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.exit = scpi_cpufreq_exit,
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.ready = scpi_cpufreq_ready,
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.target_index = scpi_cpufreq_set_target,
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};
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static int scpi_cpufreq_probe(struct platform_device *pdev)
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{
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int ret;
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scpi_ops = get_scpi_ops();
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if (!scpi_ops)
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return -EIO;
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ret = cpufreq_register_driver(&scpi_cpufreq_driver);
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if (ret)
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dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
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__func__, ret);
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return ret;
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}
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static int scpi_cpufreq_remove(struct platform_device *pdev)
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{
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cpufreq_unregister_driver(&scpi_cpufreq_driver);
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scpi_ops = NULL;
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return 0;
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}
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static struct platform_driver scpi_cpufreq_platdrv = {
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.driver = {
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.name = "scpi-cpufreq",
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},
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.probe = scpi_cpufreq_probe,
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.remove = scpi_cpufreq_remove,
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};
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module_platform_driver(scpi_cpufreq_platdrv);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
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MODULE_LICENSE("GPL v2");
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