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 
22 /**
23  * struct cpu_data
24  * @pclk: the parent clock of cpu
25  * @table: frequency table
26  */
27 struct cpu_data {
28 	struct clk **pclk;
29 	struct cpufreq_frequency_table *table;
30 };
31 
32 /*
33  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
34  * matched a more generic compatible.
35  */
36 #define SOC_BLACKLIST		1
37 
38 /**
39  * struct soc_data - SoC specific data
40  * @flags: SOC_xxx
41  */
42 struct soc_data {
43 	u32 flags;
44 };
45 
46 static u32 get_bus_freq(void)
47 {
48 	struct device_node *soc;
49 	u32 sysfreq;
50 	struct clk *pltclk;
51 	int ret;
52 
53 	/* get platform freq by searching bus-frequency property */
54 	soc = of_find_node_by_type(NULL, "soc");
55 	if (soc) {
56 		ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
57 		of_node_put(soc);
58 		if (!ret)
59 			return sysfreq;
60 	}
61 
62 	/* get platform freq by its clock name */
63 	pltclk = clk_get(NULL, "cg-pll0-div1");
64 	if (IS_ERR(pltclk)) {
65 		pr_err("%s: can't get bus frequency %ld\n",
66 		       __func__, PTR_ERR(pltclk));
67 		return PTR_ERR(pltclk);
68 	}
69 
70 	return clk_get_rate(pltclk);
71 }
72 
73 static struct clk *cpu_to_clk(int cpu)
74 {
75 	struct device_node *np;
76 	struct clk *clk;
77 
78 	if (!cpu_present(cpu))
79 		return NULL;
80 
81 	np = of_get_cpu_node(cpu, NULL);
82 	if (!np)
83 		return NULL;
84 
85 	clk = of_clk_get(np, 0);
86 	of_node_put(np);
87 	return clk;
88 }
89 
90 /* traverse cpu nodes to get cpu mask of sharing clock wire */
91 static void set_affected_cpus(struct cpufreq_policy *policy)
92 {
93 	struct cpumask *dstp = policy->cpus;
94 	struct clk *clk;
95 	int i;
96 
97 	for_each_present_cpu(i) {
98 		clk = cpu_to_clk(i);
99 		if (IS_ERR(clk)) {
100 			pr_err("%s: no clock for cpu %d\n", __func__, i);
101 			continue;
102 		}
103 
104 		if (clk_is_match(policy->clk, clk))
105 			cpumask_set_cpu(i, dstp);
106 	}
107 }
108 
109 /* reduce the duplicated frequencies in frequency table */
110 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
111 		int count)
112 {
113 	int i, j;
114 
115 	for (i = 1; i < count; i++) {
116 		for (j = 0; j < i; j++) {
117 			if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
118 					freq_table[j].frequency !=
119 					freq_table[i].frequency)
120 				continue;
121 
122 			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
123 			break;
124 		}
125 	}
126 }
127 
128 /* sort the frequencies in frequency table in descenting order */
129 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
130 		int count)
131 {
132 	int i, j, ind;
133 	unsigned int freq, max_freq;
134 	struct cpufreq_frequency_table table;
135 
136 	for (i = 0; i < count - 1; i++) {
137 		max_freq = freq_table[i].frequency;
138 		ind = i;
139 		for (j = i + 1; j < count; j++) {
140 			freq = freq_table[j].frequency;
141 			if (freq == CPUFREQ_ENTRY_INVALID ||
142 					freq <= max_freq)
143 				continue;
144 			ind = j;
145 			max_freq = freq;
146 		}
147 
148 		if (ind != i) {
149 			/* exchange the frequencies */
150 			table.driver_data = freq_table[i].driver_data;
151 			table.frequency = freq_table[i].frequency;
152 			freq_table[i].driver_data = freq_table[ind].driver_data;
153 			freq_table[i].frequency = freq_table[ind].frequency;
154 			freq_table[ind].driver_data = table.driver_data;
155 			freq_table[ind].frequency = table.frequency;
156 		}
157 	}
158 }
159 
160 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
161 {
162 	struct device_node *np;
163 	int i, count;
164 	u32 freq;
165 	struct clk *clk;
166 	const struct clk_hw *hwclk;
167 	struct cpufreq_frequency_table *table;
168 	struct cpu_data *data;
169 	unsigned int cpu = policy->cpu;
170 	u64 u64temp;
171 
172 	np = of_get_cpu_node(cpu, NULL);
173 	if (!np)
174 		return -ENODEV;
175 
176 	data = kzalloc(sizeof(*data), GFP_KERNEL);
177 	if (!data)
178 		goto err_np;
179 
180 	policy->clk = of_clk_get(np, 0);
181 	if (IS_ERR(policy->clk)) {
182 		pr_err("%s: no clock information\n", __func__);
183 		goto err_nomem2;
184 	}
185 
186 	hwclk = __clk_get_hw(policy->clk);
187 	count = clk_hw_get_num_parents(hwclk);
188 
189 	data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
190 	if (!data->pclk)
191 		goto err_nomem2;
192 
193 	table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
194 	if (!table)
195 		goto err_pclk;
196 
197 	for (i = 0; i < count; i++) {
198 		clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
199 		data->pclk[i] = clk;
200 		freq = clk_get_rate(clk);
201 		table[i].frequency = freq / 1000;
202 		table[i].driver_data = i;
203 	}
204 	freq_table_redup(table, count);
205 	freq_table_sort(table, count);
206 	table[i].frequency = CPUFREQ_TABLE_END;
207 	policy->freq_table = table;
208 	data->table = table;
209 
210 	/* update ->cpus if we have cluster, no harm if not */
211 	set_affected_cpus(policy);
212 	policy->driver_data = data;
213 
214 	/* Minimum transition latency is 12 platform clocks */
215 	u64temp = 12ULL * NSEC_PER_SEC;
216 	do_div(u64temp, get_bus_freq());
217 	policy->cpuinfo.transition_latency = u64temp + 1;
218 
219 	of_node_put(np);
220 
221 	return 0;
222 
223 err_pclk:
224 	kfree(data->pclk);
225 err_nomem2:
226 	kfree(data);
227 err_np:
228 	of_node_put(np);
229 
230 	return -ENODEV;
231 }
232 
233 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
234 {
235 	struct cpu_data *data = policy->driver_data;
236 
237 	kfree(data->pclk);
238 	kfree(data->table);
239 	kfree(data);
240 	policy->driver_data = NULL;
241 
242 	return 0;
243 }
244 
245 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
246 		unsigned int index)
247 {
248 	struct clk *parent;
249 	struct cpu_data *data = policy->driver_data;
250 
251 	parent = data->pclk[data->table[index].driver_data];
252 	return clk_set_parent(policy->clk, parent);
253 }
254 
255 static struct cpufreq_driver qoriq_cpufreq_driver = {
256 	.name		= "qoriq_cpufreq",
257 	.flags		= CPUFREQ_CONST_LOOPS |
258 			  CPUFREQ_IS_COOLING_DEV,
259 	.init		= qoriq_cpufreq_cpu_init,
260 	.exit		= qoriq_cpufreq_cpu_exit,
261 	.verify		= cpufreq_generic_frequency_table_verify,
262 	.target_index	= qoriq_cpufreq_target,
263 	.get		= cpufreq_generic_get,
264 	.attr		= cpufreq_generic_attr,
265 };
266 
267 static const struct soc_data blacklist = {
268 	.flags = SOC_BLACKLIST,
269 };
270 
271 static const struct of_device_id node_matches[] __initconst = {
272 	/* e6500 cannot use cpufreq due to erratum A-008083 */
273 	{ .compatible = "fsl,b4420-clockgen", &blacklist },
274 	{ .compatible = "fsl,b4860-clockgen", &blacklist },
275 	{ .compatible = "fsl,t2080-clockgen", &blacklist },
276 	{ .compatible = "fsl,t4240-clockgen", &blacklist },
277 
278 	{ .compatible = "fsl,ls1012a-clockgen", },
279 	{ .compatible = "fsl,ls1021a-clockgen", },
280 	{ .compatible = "fsl,ls1028a-clockgen", },
281 	{ .compatible = "fsl,ls1043a-clockgen", },
282 	{ .compatible = "fsl,ls1046a-clockgen", },
283 	{ .compatible = "fsl,ls1088a-clockgen", },
284 	{ .compatible = "fsl,ls2080a-clockgen", },
285 	{ .compatible = "fsl,lx2160a-clockgen", },
286 	{ .compatible = "fsl,p4080-clockgen", },
287 	{ .compatible = "fsl,qoriq-clockgen-1.0", },
288 	{ .compatible = "fsl,qoriq-clockgen-2.0", },
289 	{}
290 };
291 
292 static int __init qoriq_cpufreq_init(void)
293 {
294 	int ret;
295 	struct device_node  *np;
296 	const struct of_device_id *match;
297 	const struct soc_data *data;
298 
299 	np = of_find_matching_node(NULL, node_matches);
300 	if (!np)
301 		return -ENODEV;
302 
303 	match = of_match_node(node_matches, np);
304 	data = match->data;
305 
306 	of_node_put(np);
307 
308 	if (data && data->flags & SOC_BLACKLIST)
309 		return -ENODEV;
310 
311 	ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
312 	if (!ret)
313 		pr_info("Freescale QorIQ CPU frequency scaling driver\n");
314 
315 	return ret;
316 }
317 module_init(qoriq_cpufreq_init);
318 
319 static void __exit qoriq_cpufreq_exit(void)
320 {
321 	cpufreq_unregister_driver(&qoriq_cpufreq_driver);
322 }
323 module_exit(qoriq_cpufreq_exit);
324 
325 MODULE_LICENSE("GPL");
326 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
327 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
328