// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* Copyright (C) 2012 Calxeda, Inc.
|
*
|
* This driver provides the clk notifier callbacks that are used when
|
* the cpufreq-dt driver changes to frequency to alert the highbank
|
* EnergyCore Management Engine (ECME) about the need to change
|
* voltage. The ECME interfaces with the actual voltage regulators.
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
#include <linux/kernel.h>
|
#include <linux/module.h>
|
#include <linux/clk.h>
|
#include <linux/cpu.h>
|
#include <linux/err.h>
|
#include <linux/of.h>
|
#include <linux/pl320-ipc.h>
|
#include <linux/platform_device.h>
|
|
#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
|
#define HB_CPUFREQ_IPC_LEN 7
|
#define HB_CPUFREQ_VOLT_RETRIES 15
|
|
static int hb_voltage_change(unsigned int freq)
|
{
|
u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
|
|
return pl320_ipc_transmit(msg);
|
}
|
|
static int hb_cpufreq_clk_notify(struct notifier_block *nb,
|
unsigned long action, void *hclk)
|
{
|
struct clk_notifier_data *clk_data = hclk;
|
int i = 0;
|
|
if (action == PRE_RATE_CHANGE) {
|
if (clk_data->new_rate > clk_data->old_rate)
|
while (hb_voltage_change(clk_data->new_rate))
|
if (i++ > HB_CPUFREQ_VOLT_RETRIES)
|
return NOTIFY_BAD;
|
} else if (action == POST_RATE_CHANGE) {
|
if (clk_data->new_rate < clk_data->old_rate)
|
while (hb_voltage_change(clk_data->new_rate))
|
if (i++ > HB_CPUFREQ_VOLT_RETRIES)
|
return NOTIFY_BAD;
|
}
|
|
return NOTIFY_DONE;
|
}
|
|
static struct notifier_block hb_cpufreq_clk_nb = {
|
.notifier_call = hb_cpufreq_clk_notify,
|
};
|
|
static int hb_cpufreq_driver_init(void)
|
{
|
struct platform_device_info devinfo = { .name = "cpufreq-dt", };
|
struct device *cpu_dev;
|
struct clk *cpu_clk;
|
struct device_node *np;
|
int ret;
|
|
if ((!of_machine_is_compatible("calxeda,highbank")) &&
|
(!of_machine_is_compatible("calxeda,ecx-2000")))
|
return -ENODEV;
|
|
cpu_dev = get_cpu_device(0);
|
if (!cpu_dev) {
|
pr_err("failed to get highbank cpufreq device\n");
|
return -ENODEV;
|
}
|
|
np = of_node_get(cpu_dev->of_node);
|
if (!np) {
|
pr_err("failed to find highbank cpufreq node\n");
|
return -ENOENT;
|
}
|
|
cpu_clk = clk_get(cpu_dev, NULL);
|
if (IS_ERR(cpu_clk)) {
|
ret = PTR_ERR(cpu_clk);
|
pr_err("failed to get cpu0 clock: %d\n", ret);
|
goto out_put_node;
|
}
|
|
ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
|
if (ret) {
|
pr_err("failed to register clk notifier: %d\n", ret);
|
goto out_put_node;
|
}
|
|
/* Instantiate cpufreq-dt */
|
platform_device_register_full(&devinfo);
|
|
out_put_node:
|
of_node_put(np);
|
return ret;
|
}
|
module_init(hb_cpufreq_driver_init);
|
|
static const struct of_device_id __maybe_unused hb_cpufreq_of_match[] = {
|
{ .compatible = "calxeda,highbank" },
|
{ .compatible = "calxeda,ecx-2000" },
|
{ },
|
};
|
MODULE_DEVICE_TABLE(of, hb_cpufreq_of_match);
|
|
MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
|
MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
|
MODULE_LICENSE("GPL");
|
