1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
|
From 5cf343c60d7557aefb468603065cac5062f11b8d Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Fri, 30 May 2014 16:36:11 -0700
Subject: [PATCH 172/182] cpufreq: Add a cpufreq-krait based on cpufreq-cpu0
Krait processors have individual clocks for each CPU that can
scale independently from one another. cpufreq-cpu0 is fairly
close to this, but assumes that there is only one clock for all
CPUs. Add a driver to support the Krait configuration.
TODO: Merge into cpufreq-cpu0? Or make generic?
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
drivers/cpufreq/Kconfig | 13 +++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/cpufreq-krait.c | 190 +++++++++++++++++++++++++++++++++++++++
3 files changed, 204 insertions(+)
create mode 100644 drivers/cpufreq/cpufreq-krait.c
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -194,6 +194,19 @@ config GENERIC_CPUFREQ_CPU0
If in doubt, say N.
+config GENERIC_CPUFREQ_KRAIT
+ tristate "Krait cpufreq driver"
+ depends on HAVE_CLK && OF
+ # if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y:
+ depends on !CPU_THERMAL || THERMAL
+ select PM_OPP
+ help
+ This adds a generic cpufreq driver for CPU0 frequency management.
+ It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
+ systems which share clock and voltage across all CPUs.
+
+ If in doubt, say N.
+
menu "x86 CPU frequency scaling drivers"
depends on X86
source "drivers/cpufreq/Kconfig.x86"
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)
obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o
obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o
+obj-$(CONFIG_GENERIC_CPUFREQ_KRAIT) += cpufreq-krait.o
##################################################################################
# x86 drivers.
--- /dev/null
+++ b/drivers/cpufreq/cpufreq-krait.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * The OPP code in function krait_set_target() is reused from
+ * drivers/cpufreq/omap-cpufreq.c
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/cpu_cooling.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+static unsigned int transition_latency;
+
+static struct device *cpu_dev;
+static DEFINE_PER_CPU(struct clk *, krait_cpu_clks);
+static struct cpufreq_frequency_table *freq_table;
+static struct thermal_cooling_device *cdev;
+
+static int krait_set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ unsigned long volt = 0, volt_old = 0;
+ unsigned int old_freq, new_freq;
+ long freq_Hz, freq_exact;
+ int ret;
+ struct clk *cpu_clk;
+
+ cpu_clk = per_cpu(krait_cpu_clks, policy->cpu);
+
+ freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
+ if (freq_Hz <= 0)
+ freq_Hz = freq_table[index].frequency * 1000;
+
+ freq_exact = freq_Hz;
+ new_freq = freq_Hz / 1000;
+ old_freq = clk_get_rate(cpu_clk) / 1000;
+
+ pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
+ old_freq / 1000, volt_old ? volt_old / 1000 : -1,
+ new_freq / 1000, volt ? volt / 1000 : -1);
+
+ ret = clk_set_rate(cpu_clk, freq_exact);
+ if (ret)
+ pr_err("failed to set clock rate: %d\n", ret);
+
+ return ret;
+}
+
+static int krait_cpufreq_init(struct cpufreq_policy *policy)
+{
+ int ret;
+
+ policy->clk = per_cpu(krait_cpu_clks, policy->cpu);
+
+ ret = cpufreq_table_validate_and_show(policy, freq_table);
+ if (ret) {
+ pr_err("%s: invalid frequency table: %d\n", __func__, ret);
+ return ret;
+ }
+
+ policy->cpuinfo.transition_latency = transition_latency;
+
+ return 0;
+}
+
+static struct cpufreq_driver krait_cpufreq_driver = {
+ .flags = CPUFREQ_STICKY,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = krait_set_target,
+ .get = cpufreq_generic_get,
+ .init = krait_cpufreq_init,
+ .name = "generic_krait",
+ .attr = cpufreq_generic_attr,
+};
+
+static int krait_cpufreq_probe(struct platform_device *pdev)
+{
+ struct device_node *np;
+ int ret;
+ unsigned int cpu;
+ struct device *dev;
+ struct clk *clk;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev) {
+ pr_err("failed to get krait device\n");
+ return -ENODEV;
+ }
+
+ np = of_node_get(cpu_dev->of_node);
+ if (!np) {
+ pr_err("failed to find krait node\n");
+ return -ENOENT;
+ }
+
+ for_each_possible_cpu(cpu) {
+ dev = get_cpu_device(cpu);
+ if (!dev) {
+ pr_err("failed to get krait device\n");
+ ret = -ENOENT;
+ goto out_put_node;
+ }
+ per_cpu(krait_cpu_clks, cpu) = clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ goto out_put_node;
+ }
+ }
+
+ ret = of_init_opp_table(cpu_dev);
+ if (ret) {
+ pr_err("failed to init OPP table: %d\n", ret);
+ goto out_put_node;
+ }
+
+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+ if (ret) {
+ pr_err("failed to init cpufreq table: %d\n", ret);
+ goto out_put_node;
+ }
+
+ if (of_property_read_u32(np, "clock-latency", &transition_latency))
+ transition_latency = CPUFREQ_ETERNAL;
+
+ ret = cpufreq_register_driver(&krait_cpufreq_driver);
+ if (ret) {
+ pr_err("failed register driver: %d\n", ret);
+ goto out_free_table;
+ }
+ of_node_put(np);
+
+ /*
+ * For now, just loading the cooling device;
+ * thermal DT code takes care of matching them.
+ */
+ for_each_possible_cpu(cpu) {
+ dev = get_cpu_device(cpu);
+ np = of_node_get(dev->of_node);
+ if (of_find_property(np, "#cooling-cells", NULL)) {
+ cdev = of_cpufreq_cooling_register(np, cpumask_of(cpu));
+ if (IS_ERR(cdev))
+ pr_err("running cpufreq without cooling device: %ld\n",
+ PTR_ERR(cdev));
+ }
+ of_node_put(np);
+ }
+
+ return 0;
+
+out_free_table:
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_put_node:
+ of_node_put(np);
+ return ret;
+}
+
+static int krait_cpufreq_remove(struct platform_device *pdev)
+{
+ cpufreq_cooling_unregister(cdev);
+ cpufreq_unregister_driver(&krait_cpufreq_driver);
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+
+ return 0;
+}
+
+static struct platform_driver krait_cpufreq_platdrv = {
+ .driver = {
+ .name = "cpufreq-krait",
+ .owner = THIS_MODULE,
+ },
+ .probe = krait_cpufreq_probe,
+ .remove = krait_cpufreq_remove,
+};
+module_platform_driver(krait_cpufreq_platdrv);
+
+MODULE_DESCRIPTION("Krait CPUfreq driver");
+MODULE_LICENSE("GPL v2");
|
