[GitHub/mt8127/android_kernel_alcatel_ttab.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)
{
	int i;
	u32 msg[HB_CPUFREQ_IPC_LEN];

	msg[0] = HB_CPUFREQ_CHANGE_NOTE;
	msg[1] = freq / 1000000;
	for (i = 2; i < HB_CPUFREQ_IPC_LEN; i++)
		msg[i] = 0;

	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;

	for_each_child_of_node(of_find_node_by_path("/cpus"), np)
		if (of_get_property(np, "operating-points", NULL))
			break;

	if (!np) {
		pr_err("failed to find highbank cpufreq node\n");
		return -ENOENT;
	}

	cpu_dev = get_cpu_device(0);
	if (!cpu_dev) {
		pr_err("failed to get highbank cpufreq device\n");
		ret = -ENODEV;
		goto out_put_node;
	}

	cpu_dev->of_node = np;

	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	{
	31	int i;
	32	u32 msg[HB_CPUFREQ_IPC_LEN];
	33
	34	msg[0] = HB_CPUFREQ_CHANGE_NOTE;
	35	msg[1] = freq / 1000000;
	36	for (i = 2; i < HB_CPUFREQ_IPC_LEN; i++)
	37	msg[i] = 0;
	38
	39	return pl320_ipc_transmit(msg);
	40	}
	41
	42	static int hb_cpufreq_clk_notify(struct notifier_block *nb,
	43	unsigned long action, void *hclk)
	44	{
	45	struct clk_notifier_data *clk_data = hclk;
	46	int i = 0;
	47
	48	if (action == PRE_RATE_CHANGE) {
	49	if (clk_data->new_rate > clk_data->old_rate)
	50	while (hb_voltage_change(clk_data->new_rate))
	51	if (i++ > HB_CPUFREQ_VOLT_RETRIES)
	52	return NOTIFY_BAD;
	53	} else if (action == POST_RATE_CHANGE) {
	54	if (clk_data->new_rate < clk_data->old_rate)
	55	while (hb_voltage_change(clk_data->new_rate))
	56	if (i++ > HB_CPUFREQ_VOLT_RETRIES)
	57	return NOTIFY_BAD;
	58	}
	59
	60	return NOTIFY_DONE;
	61	}
	62
	63	static struct notifier_block hb_cpufreq_clk_nb = {
	64	.notifier_call = hb_cpufreq_clk_notify,
	65	};
	66
	67	static int hb_cpufreq_driver_init(void)
	68	{
5553f9e2	69	struct platform_device_info devinfo = { .name = "cpufreq-cpu0", };
6754f556 ML	70	struct device *cpu_dev;
	71	struct clk *cpu_clk;
	72	struct device_node *np;
	73	int ret;
	74
	75	if (!of_machine_is_compatible("calxeda,highbank"))
	76	return -ENODEV;
	77
	78	for_each_child_of_node(of_find_node_by_path("/cpus"), np)
	79	if (of_get_property(np, "operating-points", NULL))
	80	break;
	81
	82	if (!np) {
	83	pr_err("failed to find highbank cpufreq node\n");
	84	return -ENOENT;
	85	}
	86
	87	cpu_dev = get_cpu_device(0);
	88	if (!cpu_dev) {
	89	pr_err("failed to get highbank cpufreq device\n");
	90	ret = -ENODEV;
	91	goto out_put_node;
	92	}
	93
	94	cpu_dev->of_node = np;
	95
	96	cpu_clk = clk_get(cpu_dev, NULL);
	97	if (IS_ERR(cpu_clk)) {
	98	ret = PTR_ERR(cpu_clk);
	99	pr_err("failed to get cpu0 clock: %d\n", ret);
	100	goto out_put_node;
	101	}
	102
	103	ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
	104	if (ret) {
	105	pr_err("failed to register clk notifier: %d\n", ret);
	106	goto out_put_node;
	107	}
	108
5553f9e2 SG	109	/* Instantiate cpufreq-cpu0 */
	110	platform_device_register_full(&devinfo);
	111
6754f556 ML	112	out_put_node:
	113	of_node_put(np);
	114	return ret;
	115	}
	116	module_init(hb_cpufreq_driver_init);
	117
	118	MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
	119	MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
	120	MODULE_LICENSE("GPL");