1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2013 Freescale Semiconductor, Inc.
4 *
5 * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
6 */
7
8#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
9
10#include <linux/clk.h>
11#include <linux/clk-provider.h>
12#include <linux/cpufreq.h>
13#include <linux/errno.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/of.h>
19#include <linux/slab.h>
20#include <linux/smp.h>
21#include <linux/platform_device.h>
22
23/**
24 * struct cpu_data
25 * @pclk: the parent clock of cpu
26 * @table: frequency table
27 */
28struct cpu_data {
29	struct clk **pclk;
30	struct cpufreq_frequency_table *table;
31};
32
33/**
34 * struct soc_data - SoC specific data
35 * @flags: SOC_xxx
36 */
37struct soc_data {
38	u32 flags;
39};
40
41static u32 get_bus_freq(void)
42{
43	struct device_node *soc;
44	u32 sysfreq;
45	struct clk *pltclk;
46	int ret;
47
48	/* get platform freq by searching bus-frequency property */
49	soc = of_find_node_by_type(NULL, "soc");
50	if (soc) {
51		ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
52		of_node_put(soc);
53		if (!ret)
54			return sysfreq;
55	}
56
57	/* get platform freq by its clock name */
58	pltclk = clk_get(NULL, "cg-pll0-div1");
59	if (IS_ERR(pltclk)) {
60		pr_err("%s: can't get bus frequency %ld\n",
61		       __func__, PTR_ERR(pltclk));
62		return PTR_ERR(pltclk);
63	}
64
65	return clk_get_rate(pltclk);
66}
67
68static struct clk *cpu_to_clk(int cpu)
69{
70	struct device_node *np;
71	struct clk *clk;
72
73	if (!cpu_present(cpu))
74		return NULL;
75
76	np = of_get_cpu_node(cpu, NULL);
77	if (!np)
78		return NULL;
79
80	clk = of_clk_get(np, 0);
81	of_node_put(np);
82	return clk;
83}
84
85/* traverse cpu nodes to get cpu mask of sharing clock wire */
86static void set_affected_cpus(struct cpufreq_policy *policy)
87{
88	struct cpumask *dstp = policy->cpus;
89	struct clk *clk;
90	int i;
91
92	for_each_present_cpu(i) {
93		clk = cpu_to_clk(i);
94		if (IS_ERR(clk)) {
95			pr_err("%s: no clock for cpu %d\n", __func__, i);
96			continue;
97		}
98
99		if (clk_is_match(policy->clk, clk))
100			cpumask_set_cpu(i, dstp);
101	}
102}
103
104/* reduce the duplicated frequencies in frequency table */
105static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
106		int count)
107{
108	int i, j;
109
110	for (i = 1; i < count; i++) {
111		for (j = 0; j < i; j++) {
112			if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
113					freq_table[j].frequency !=
114					freq_table[i].frequency)
115				continue;
116
117			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
118			break;
119		}
120	}
121}
122
123/* sort the frequencies in frequency table in descenting order */
124static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
125		int count)
126{
127	int i, j, ind;
128	unsigned int freq, max_freq;
129	struct cpufreq_frequency_table table;
130
131	for (i = 0; i < count - 1; i++) {
132		max_freq = freq_table[i].frequency;
133		ind = i;
134		for (j = i + 1; j < count; j++) {
135			freq = freq_table[j].frequency;
136			if (freq == CPUFREQ_ENTRY_INVALID ||
137					freq <= max_freq)
138				continue;
139			ind = j;
140			max_freq = freq;
141		}
142
143		if (ind != i) {
144			/* exchange the frequencies */
145			table.driver_data = freq_table[i].driver_data;
146			table.frequency = freq_table[i].frequency;
147			freq_table[i].driver_data = freq_table[ind].driver_data;
148			freq_table[i].frequency = freq_table[ind].frequency;
149			freq_table[ind].driver_data = table.driver_data;
150			freq_table[ind].frequency = table.frequency;
151		}
152	}
153}
154
155static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
156{
157	struct device_node *np;
158	int i, count;
159	u32 freq;
160	struct clk *clk;
161	const struct clk_hw *hwclk;
162	struct cpufreq_frequency_table *table;
163	struct cpu_data *data;
164	unsigned int cpu = policy->cpu;
165	u64 u64temp;
166
167	np = of_get_cpu_node(cpu, NULL);
168	if (!np)
169		return -ENODEV;
170
171	data = kzalloc(sizeof(*data), GFP_KERNEL);
172	if (!data)
173		goto err_np;
174
175	policy->clk = of_clk_get(np, 0);
176	if (IS_ERR(policy->clk)) {
177		pr_err("%s: no clock information\n", __func__);
178		goto err_nomem2;
179	}
180
181	hwclk = __clk_get_hw(policy->clk);
182	count = clk_hw_get_num_parents(hwclk);
183
184	data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
185	if (!data->pclk)
186		goto err_nomem2;
187
188	table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
189	if (!table)
190		goto err_pclk;
191
192	for (i = 0; i < count; i++) {
193		clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
194		data->pclk[i] = clk;
195		freq = clk_get_rate(clk);
196		table[i].frequency = freq / 1000;
197		table[i].driver_data = i;
198	}
199	freq_table_redup(table, count);
200	freq_table_sort(table, count);
201	table[i].frequency = CPUFREQ_TABLE_END;
202	policy->freq_table = table;
203	data->table = table;
204
205	/* update ->cpus if we have cluster, no harm if not */
206	set_affected_cpus(policy);
207	policy->driver_data = data;
208
209	/* Minimum transition latency is 12 platform clocks */
210	u64temp = 12ULL * NSEC_PER_SEC;
211	do_div(u64temp, get_bus_freq());
212	policy->cpuinfo.transition_latency = u64temp + 1;
213
214	of_node_put(np);
215
216	return 0;
217
218err_pclk:
219	kfree(data->pclk);
220err_nomem2:
221	kfree(data);
222err_np:
223	of_node_put(np);
224
225	return -ENODEV;
226}
227
228static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
229{
230	struct cpu_data *data = policy->driver_data;
231
232	kfree(data->pclk);
233	kfree(data->table);
234	kfree(data);
235	policy->driver_data = NULL;
236
237	return 0;
238}
239
240static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
241		unsigned int index)
242{
243	struct clk *parent;
244	struct cpu_data *data = policy->driver_data;
245
246	parent = data->pclk[data->table[index].driver_data];
247	return clk_set_parent(policy->clk, parent);
248}
249
250static struct cpufreq_driver qoriq_cpufreq_driver = {
251	.name		= "qoriq_cpufreq",
252	.flags		= CPUFREQ_CONST_LOOPS |
253			  CPUFREQ_IS_COOLING_DEV,
254	.init		= qoriq_cpufreq_cpu_init,
255	.exit		= qoriq_cpufreq_cpu_exit,
256	.verify		= cpufreq_generic_frequency_table_verify,
257	.target_index	= qoriq_cpufreq_target,
258	.get		= cpufreq_generic_get,
259	.attr		= cpufreq_generic_attr,
260};
261
262static const struct of_device_id qoriq_cpufreq_blacklist[] = {
263	/* e6500 cannot use cpufreq due to erratum A-008083 */
264	{ .compatible = "fsl,b4420-clockgen", },
265	{ .compatible = "fsl,b4860-clockgen", },
266	{ .compatible = "fsl,t2080-clockgen", },
267	{ .compatible = "fsl,t4240-clockgen", },
268	{}
269};
270
271static int qoriq_cpufreq_probe(struct platform_device *pdev)
272{
273	int ret;
274	struct device_node *np;
275
276	np = of_find_matching_node(NULL, qoriq_cpufreq_blacklist);
277	if (np) {
278		of_node_put(np);
279		dev_info(&pdev->dev, "Disabling due to erratum A-008083");
280		return -ENODEV;
281	}
282
283	ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
284	if (ret)
285		return ret;
286
287	dev_info(&pdev->dev, "Freescale QorIQ CPU frequency scaling driver\n");
288	return 0;
289}
290
291static void qoriq_cpufreq_remove(struct platform_device *pdev)
292{
293	cpufreq_unregister_driver(&qoriq_cpufreq_driver);
294}
295
296static struct platform_driver qoriq_cpufreq_platform_driver = {
297	.driver = {
298		.name = "qoriq-cpufreq",
299	},
300	.probe = qoriq_cpufreq_probe,
301	.remove_new = qoriq_cpufreq_remove,
302};
303module_platform_driver(qoriq_cpufreq_platform_driver);
304
305MODULE_ALIAS("platform:qoriq-cpufreq");
306MODULE_LICENSE("GPL");
307MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
308MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
309