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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Calxeda, Inc.
4 *
5 * This driver provides the clk notifier callbacks that are used when
6 * the cpufreq-dt driver changes to frequency to alert the highbank
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>
19#include <linux/pl320-ipc.h>
20#include <linux/platform_device.h>
21
22#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
23#define HB_CPUFREQ_IPC_LEN 7
24#define HB_CPUFREQ_VOLT_RETRIES 15
25
26static int hb_voltage_change(unsigned int freq)
27{
28 u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
29
30 return pl320_ipc_transmit(msg);
31}
32
33static 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
54static struct notifier_block hb_cpufreq_clk_nb = {
55 .notifier_call = hb_cpufreq_clk_notify,
56};
57
58static int __init hb_cpufreq_driver_init(void)
59{
60 struct platform_device_info devinfo = { .name = "cpufreq-dt", };
61 struct device *cpu_dev;
62 struct clk *cpu_clk;
63 struct device_node *np;
64 int ret;
65
66 if ((!of_machine_is_compatible("calxeda,highbank")) &&
67 (!of_machine_is_compatible("calxeda,ecx-2000")))
68 return -ENODEV;
69
70 cpu_dev = get_cpu_device(0);
71 if (!cpu_dev) {
72 pr_err("failed to get highbank cpufreq device\n");
73 return -ENODEV;
74 }
75
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 }
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
95 /* Instantiate cpufreq-dt */
96 platform_device_register_full(&devinfo);
97
98out_put_node:
99 of_node_put(np);
100 return ret;
101}
102module_init(hb_cpufreq_driver_init);
103
104static const struct of_device_id __maybe_unused hb_cpufreq_of_match[] = {
105 { .compatible = "calxeda,highbank" },
106 { .compatible = "calxeda,ecx-2000" },
107 { },
108};
109MODULE_DEVICE_TABLE(of, hb_cpufreq_of_match);
110
111MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
112MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
113MODULE_LICENSE("GPL");
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-dt 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/pl320-ipc.h>
23#include <linux/platform_device.h>
24
25#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
26#define HB_CPUFREQ_IPC_LEN 7
27#define HB_CPUFREQ_VOLT_RETRIES 15
28
29static int hb_voltage_change(unsigned int freq)
30{
31 u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};
32
33 return pl320_ipc_transmit(msg);
34}
35
36static 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
57static struct notifier_block hb_cpufreq_clk_nb = {
58 .notifier_call = hb_cpufreq_clk_notify,
59};
60
61static int hb_cpufreq_driver_init(void)
62{
63 struct platform_device_info devinfo = { .name = "cpufreq-dt", };
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 (!of_machine_is_compatible("calxeda,ecx-2000")))
71 return -ENODEV;
72
73 cpu_dev = get_cpu_device(0);
74 if (!cpu_dev) {
75 pr_err("failed to get highbank cpufreq device\n");
76 return -ENODEV;
77 }
78
79 np = of_node_get(cpu_dev->of_node);
80 if (!np) {
81 pr_err("failed to find highbank cpufreq node\n");
82 return -ENOENT;
83 }
84
85 cpu_clk = clk_get(cpu_dev, NULL);
86 if (IS_ERR(cpu_clk)) {
87 ret = PTR_ERR(cpu_clk);
88 pr_err("failed to get cpu0 clock: %d\n", ret);
89 goto out_put_node;
90 }
91
92 ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
93 if (ret) {
94 pr_err("failed to register clk notifier: %d\n", ret);
95 goto out_put_node;
96 }
97
98 /* Instantiate cpufreq-dt */
99 platform_device_register_full(&devinfo);
100
101out_put_node:
102 of_node_put(np);
103 return ret;
104}
105module_init(hb_cpufreq_driver_init);
106
107MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
108MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
109MODULE_LICENSE("GPL");