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

/*
 * Copyright (C) 2012 Calxeda, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This driver provides the clk notifier callbacks that are used when
 * the cpufreq-cpu0 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/mailbox.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-cpu0", };
	struct device *cpu_dev;
	struct clk *cpu_clk;
	struct device_node *np;
	int ret;

	if (!of_machine_is_compatible("calxeda,highbank"))
		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-cpu0 */
	platform_device_register_full(&devinfo);

out_put_node:
	of_node_put(np);
	return ret;
}
module_init(hb_cpufreq_driver_init);

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