GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / qoriq-cpufreq.c
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  */
28 struct 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  */
37 struct soc_data {
38         u32 flags;
39 };
40
41 static 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
68 static 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 */
86 static 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 */
105 static 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 */
124 static 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
155 static 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
218 err_pclk:
219         kfree(data->pclk);
220 err_nomem2:
221         kfree(data);
222 err_np:
223         of_node_put(np);
224
225         return -ENODEV;
226 }
227
228 static 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
240 static 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
250 static 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
262 static 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
271 static 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
291 static int qoriq_cpufreq_remove(struct platform_device *pdev)
292 {
293         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
294
295         return 0;
296 }
297
298 static struct platform_driver qoriq_cpufreq_platform_driver = {
299         .driver = {
300                 .name = "qoriq-cpufreq",
301         },
302         .probe = qoriq_cpufreq_probe,
303         .remove = qoriq_cpufreq_remove,
304 };
305 module_platform_driver(qoriq_cpufreq_platform_driver);
306
307 MODULE_ALIAS("platform:qoriq-cpufreq");
308 MODULE_LICENSE("GPL");
309 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
310 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");