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bbcf071969
The naming convention of this driver was always under the scanner, people complained that it should have a more generic name than cpu0, as it manages all CPUs that are sharing clock lines. Also, in future it will be modified to support any number of clusters with separate clock/voltage lines. Lets rename it to 'cpufreq_dt' from 'cpufreq_cpu0'. Tested-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
109 lines
2.8 KiB
C
109 lines
2.8 KiB
C
/*
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* Copyright (C) 2012 Calxeda, Inc.
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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 driver provides the clk notifier callbacks that are used when
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* the cpufreq-dt driver changes to frequency to alert the highbank
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* EnergyCore Management Engine (ECME) about the need to change
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* voltage. The ECME interfaces with the actual voltage regulators.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/mailbox.h>
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#include <linux/platform_device.h>
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#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
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#define HB_CPUFREQ_IPC_LEN 7
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#define HB_CPUFREQ_VOLT_RETRIES 15
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static int hb_voltage_change(unsigned int freq)
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{
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u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
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return pl320_ipc_transmit(msg);
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}
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static int hb_cpufreq_clk_notify(struct notifier_block *nb,
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unsigned long action, void *hclk)
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{
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struct clk_notifier_data *clk_data = hclk;
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int i = 0;
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if (action == PRE_RATE_CHANGE) {
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if (clk_data->new_rate > clk_data->old_rate)
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while (hb_voltage_change(clk_data->new_rate))
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if (i++ > HB_CPUFREQ_VOLT_RETRIES)
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return NOTIFY_BAD;
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} else if (action == POST_RATE_CHANGE) {
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if (clk_data->new_rate < clk_data->old_rate)
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while (hb_voltage_change(clk_data->new_rate))
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if (i++ > HB_CPUFREQ_VOLT_RETRIES)
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return NOTIFY_BAD;
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block hb_cpufreq_clk_nb = {
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.notifier_call = hb_cpufreq_clk_notify,
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};
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static int hb_cpufreq_driver_init(void)
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{
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struct platform_device_info devinfo = { .name = "cpufreq-dt", };
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struct device *cpu_dev;
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struct clk *cpu_clk;
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struct device_node *np;
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int ret;
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if ((!of_machine_is_compatible("calxeda,highbank")) &&
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(!of_machine_is_compatible("calxeda,ecx-2000")))
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return -ENODEV;
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev) {
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pr_err("failed to get highbank cpufreq device\n");
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return -ENODEV;
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}
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np = of_node_get(cpu_dev->of_node);
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if (!np) {
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pr_err("failed to find highbank cpufreq node\n");
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return -ENOENT;
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}
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cpu_clk = clk_get(cpu_dev, NULL);
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if (IS_ERR(cpu_clk)) {
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ret = PTR_ERR(cpu_clk);
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pr_err("failed to get cpu0 clock: %d\n", ret);
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goto out_put_node;
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}
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ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
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if (ret) {
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pr_err("failed to register clk notifier: %d\n", ret);
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goto out_put_node;
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}
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/* Instantiate cpufreq-dt */
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platform_device_register_full(&devinfo);
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out_put_node:
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of_node_put(np);
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return ret;
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}
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module_init(hb_cpufreq_driver_init);
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MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
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MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
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MODULE_LICENSE("GPL");
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