[linux-block.git] / drivers / cpufreq / highbank-cpufreq.c

// 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 __init 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");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
6754f556 ML	2	/*
	3	* Copyright (C) 2012 Calxeda, Inc.
	4	*
6754f556	5	* This driver provides the clk notifier callbacks that are used when
bbcf0719	6	* the cpufreq-dt driver changes to frequency to alert the highbank
6754f556 ML	7	* EnergyCore Management Engine (ECME) about the need to change
	8	* voltage. The ECME interfaces with the actual voltage regulators.
	9	*/
	10
	11	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	12
	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
	15	#include <linux/clk.h>
	16	#include <linux/cpu.h>
	17	#include <linux/err.h>
	18	#include <linux/of.h>
f2fc42b6	19	#include <linux/pl320-ipc.h>
5553f9e2	20	#include <linux/platform_device.h>
6754f556 ML	21
	22	#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
	23	#define HB_CPUFREQ_IPC_LEN 7
	24	#define HB_CPUFREQ_VOLT_RETRIES 15
	25
	26	static int hb_voltage_change(unsigned int freq)
	27	{
f5f43dcf	28	u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
6754f556 ML	29
	30	return pl320_ipc_transmit(msg);
	31	}
	32
	33	static int hb_cpufreq_clk_notify(struct notifier_block *nb,
	34	unsigned long action, void *hclk)
	35	{
	36	struct clk_notifier_data *clk_data = hclk;
	37	int i = 0;
	38
	39	if (action == PRE_RATE_CHANGE) {
	40	if (clk_data->new_rate > clk_data->old_rate)
	41	while (hb_voltage_change(clk_data->new_rate))
	42	if (i++ > HB_CPUFREQ_VOLT_RETRIES)
	43	return NOTIFY_BAD;
	44	} else if (action == POST_RATE_CHANGE) {
	45	if (clk_data->new_rate < clk_data->old_rate)
	46	while (hb_voltage_change(clk_data->new_rate))
	47	if (i++ > HB_CPUFREQ_VOLT_RETRIES)
	48	return NOTIFY_BAD;
	49	}
	50
	51	return NOTIFY_DONE;
	52	}
	53
	54	static struct notifier_block hb_cpufreq_clk_nb = {
	55	.notifier_call = hb_cpufreq_clk_notify,
	56	};
	57
f7968c22	58	static int __init hb_cpufreq_driver_init(void)
6754f556	59	{
bbcf0719	60	struct platform_device_info devinfo = { .name = "cpufreq-dt", };
6754f556 ML	61	struct device *cpu_dev;
	62	struct clk *cpu_clk;
	63	struct device_node *np;
	64	int ret;
	65
fbbc5bfb ML	66	if ((!of_machine_is_compatible("calxeda,highbank")) &&
fbbc5bfb ML	67	(!of_machine_is_compatible("calxeda,ecx-2000")))
6754f556 ML	68	return -ENODEV;
6754f556 ML	69
6754f556 ML	70	cpu_dev = get_cpu_device(0);
	71	if (!cpu_dev) {
	72	pr_err("failed to get highbank cpufreq device\n");
5de6e94a	73	return -ENODEV;
6754f556 ML	74	}
6754f556 ML	75
5de6e94a SK	76	np = of_node_get(cpu_dev->of_node);
	77	if (!np) {
	78	pr_err("failed to find highbank cpufreq node\n");
	79	return -ENOENT;
	80	}
6754f556 ML	81
	82	cpu_clk = clk_get(cpu_dev, NULL);
	83	if (IS_ERR(cpu_clk)) {
	84	ret = PTR_ERR(cpu_clk);
	85	pr_err("failed to get cpu0 clock: %d\n", ret);
	86	goto out_put_node;
	87	}
	88
	89	ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
	90	if (ret) {
	91	pr_err("failed to register clk notifier: %d\n", ret);
	92	goto out_put_node;
	93	}
	94
bbcf0719	95	/* Instantiate cpufreq-dt */
5553f9e2 SG	96	platform_device_register_full(&devinfo);
5553f9e2 SG	97
6754f556 ML	98	out_put_node:
	99	of_node_put(np);
	100	return ret;
	101	}
	102	module_init(hb_cpufreq_driver_init);
	103
9433777a PR	104	static const struct of_device_id __maybe_unused hb_cpufreq_of_match[] = {
	105	{ .compatible = "calxeda,highbank" },
	106	{ .compatible = "calxeda,ecx-2000" },
	107	{ },
	108	};
	109	MODULE_DEVICE_TABLE(of, hb_cpufreq_of_match);
	110
6754f556 ML	111	MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
	112	MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
	113	MODULE_LICENSE("GPL");