forked from Minki/linux
92a9b5c291
If arm_big_little_dt driver is enabled, then it will always try to register with big LITTLE cpufreq core driver. In case DT doesn't have relevant data for cpu nodes, i.e. operating points aren't present, then we should exit early and shouldn't register with big LITTLE cpufreq core driver. Otherwise we will fail continuously from the driver->init() routine. This patch fixes this issue. Reported-and-tested-by: Jon Medhurst <tixy@linaro.org> Reviewed-by: Jon Medhurst <tixy@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
120 lines
2.8 KiB
C
120 lines
2.8 KiB
C
/*
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* Generic big.LITTLE CPUFreq Interface driver
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*
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* It provides necessary ops to arm_big_little cpufreq driver and gets
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* Frequency information from Device Tree. Freq table in DT must be in KHz.
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*
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* Copyright (C) 2013 Linaro.
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* Viresh Kumar <viresh.kumar@linaro.org>
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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/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/opp.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include "arm_big_little.h"
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/* get cpu node with valid operating-points */
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static struct device_node *get_cpu_node_with_valid_op(int cpu)
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{
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struct device_node *np = NULL, *parent;
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int count = 0;
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parent = of_find_node_by_path("/cpus");
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if (!parent) {
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pr_err("failed to find OF /cpus\n");
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return NULL;
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}
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for_each_child_of_node(parent, np) {
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if (count++ != cpu)
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continue;
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if (!of_get_property(np, "operating-points", NULL)) {
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of_node_put(np);
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np = NULL;
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}
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break;
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}
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of_node_put(parent);
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return np;
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}
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static int dt_init_opp_table(struct device *cpu_dev)
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{
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struct device_node *np;
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int ret;
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np = get_cpu_node_with_valid_op(cpu_dev->id);
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if (!np)
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return -ENODATA;
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cpu_dev->of_node = np;
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ret = of_init_opp_table(cpu_dev);
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of_node_put(np);
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return ret;
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}
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static int dt_get_transition_latency(struct device *cpu_dev)
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{
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struct device_node *np;
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u32 transition_latency = CPUFREQ_ETERNAL;
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np = get_cpu_node_with_valid_op(cpu_dev->id);
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if (!np)
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return CPUFREQ_ETERNAL;
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of_property_read_u32(np, "clock-latency", &transition_latency);
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of_node_put(np);
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pr_debug("%s: clock-latency: %d\n", __func__, transition_latency);
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return transition_latency;
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}
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static struct cpufreq_arm_bL_ops dt_bL_ops = {
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.name = "dt-bl",
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.get_transition_latency = dt_get_transition_latency,
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.init_opp_table = dt_init_opp_table,
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};
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static int generic_bL_init(void)
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{
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struct device_node *np;
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np = get_cpu_node_with_valid_op(0);
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if (!np)
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return -ENODEV;
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of_node_put(np);
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return bL_cpufreq_register(&dt_bL_ops);
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}
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module_init(generic_bL_init);
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static void generic_bL_exit(void)
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{
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return bL_cpufreq_unregister(&dt_bL_ops);
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}
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module_exit(generic_bL_exit);
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MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
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MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
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MODULE_LICENSE("GPL");
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