1 /*
2  * Copyright 2013 Freescale Semiconductor, Inc.
3  *
4  * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
12 
13 #include <linux/clk.h>
14 #include <linux/clk-provider.h>
15 #include <linux/cpufreq.h>
16 #include <linux/cpu_cooling.h>
17 #include <linux/errno.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/of.h>
23 #include <linux/slab.h>
24 #include <linux/smp.h>
25 
26 /**
27  * struct cpu_data
28  * @pclk: the parent clock of cpu
29  * @table: frequency table
30  */
31 struct cpu_data {
32 	struct clk **pclk;
33 	struct cpufreq_frequency_table *table;
34 	struct thermal_cooling_device *cdev;
35 };
36 
37 /*
38  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
39  * matched a more generic compatible.
40  */
41 #define SOC_BLACKLIST		1
42 
43 /**
44  * struct soc_data - SoC specific data
45  * @flags: SOC_xxx
46  */
47 struct soc_data {
48 	u32 flags;
49 };
50 
51 static u32 get_bus_freq(void)
52 {
53 	struct device_node *soc;
54 	u32 sysfreq;
55 
56 	soc = of_find_node_by_type(NULL, "soc");
57 	if (!soc)
58 		return 0;
59 
60 	if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
61 		sysfreq = 0;
62 
63 	of_node_put(soc);
64 
65 	return sysfreq;
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, ret;
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 		pr_err("%s: no memory\n", __func__);
187 		goto err_nomem2;
188 	}
189 
190 	table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
191 	if (!table) {
192 		pr_err("%s: no memory\n", __func__);
193 		goto err_pclk;
194 	}
195 
196 	for (i = 0; i < count; i++) {
197 		clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
198 		data->pclk[i] = clk;
199 		freq = clk_get_rate(clk);
200 		table[i].frequency = freq / 1000;
201 		table[i].driver_data = i;
202 	}
203 	freq_table_redup(table, count);
204 	freq_table_sort(table, count);
205 	table[i].frequency = CPUFREQ_TABLE_END;
206 
207 	/* set the min and max frequency properly */
208 	ret = cpufreq_table_validate_and_show(policy, table);
209 	if (ret) {
210 		pr_err("invalid frequency table: %d\n", ret);
211 		goto err_nomem1;
212 	}
213 
214 	data->table = table;
215 
216 	/* update ->cpus if we have cluster, no harm if not */
217 	set_affected_cpus(policy);
218 	policy->driver_data = data;
219 
220 	/* Minimum transition latency is 12 platform clocks */
221 	u64temp = 12ULL * NSEC_PER_SEC;
222 	do_div(u64temp, get_bus_freq());
223 	policy->cpuinfo.transition_latency = u64temp + 1;
224 
225 	of_node_put(np);
226 
227 	return 0;
228 
229 err_nomem1:
230 	kfree(table);
231 err_pclk:
232 	kfree(data->pclk);
233 err_nomem2:
234 	kfree(data);
235 err_np:
236 	of_node_put(np);
237 
238 	return -ENODEV;
239 }
240 
241 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
242 {
243 	struct cpu_data *data = policy->driver_data;
244 
245 	cpufreq_cooling_unregister(data->cdev);
246 	kfree(data->pclk);
247 	kfree(data->table);
248 	kfree(data);
249 	policy->driver_data = NULL;
250 
251 	return 0;
252 }
253 
254 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
255 		unsigned int index)
256 {
257 	struct clk *parent;
258 	struct cpu_data *data = policy->driver_data;
259 
260 	parent = data->pclk[data->table[index].driver_data];
261 	return clk_set_parent(policy->clk, parent);
262 }
263 
264 
265 static void qoriq_cpufreq_ready(struct cpufreq_policy *policy)
266 {
267 	struct cpu_data *cpud = policy->driver_data;
268 	struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
269 
270 	if (of_find_property(np, "#cooling-cells", NULL)) {
271 		cpud->cdev = of_cpufreq_cooling_register(np,
272 							 policy->related_cpus);
273 
274 		if (IS_ERR(cpud->cdev) && PTR_ERR(cpud->cdev) != -ENOSYS) {
275 			pr_err("cpu%d is not running as cooling device: %ld\n",
276 					policy->cpu, PTR_ERR(cpud->cdev));
277 
278 			cpud->cdev = NULL;
279 		}
280 	}
281 
282 	of_node_put(np);
283 }
284 
285 static struct cpufreq_driver qoriq_cpufreq_driver = {
286 	.name		= "qoriq_cpufreq",
287 	.flags		= CPUFREQ_CONST_LOOPS,
288 	.init		= qoriq_cpufreq_cpu_init,
289 	.exit		= qoriq_cpufreq_cpu_exit,
290 	.verify		= cpufreq_generic_frequency_table_verify,
291 	.target_index	= qoriq_cpufreq_target,
292 	.get		= cpufreq_generic_get,
293 	.ready		= qoriq_cpufreq_ready,
294 	.attr		= cpufreq_generic_attr,
295 };
296 
297 static const struct soc_data blacklist = {
298 	.flags = SOC_BLACKLIST,
299 };
300 
301 static const struct of_device_id node_matches[] __initconst = {
302 	/* e6500 cannot use cpufreq due to erratum A-008083 */
303 	{ .compatible = "fsl,b4420-clockgen", &blacklist },
304 	{ .compatible = "fsl,b4860-clockgen", &blacklist },
305 	{ .compatible = "fsl,t2080-clockgen", &blacklist },
306 	{ .compatible = "fsl,t4240-clockgen", &blacklist },
307 
308 	{ .compatible = "fsl,ls1012a-clockgen", },
309 	{ .compatible = "fsl,ls1021a-clockgen", },
310 	{ .compatible = "fsl,ls1043a-clockgen", },
311 	{ .compatible = "fsl,ls1046a-clockgen", },
312 	{ .compatible = "fsl,ls1088a-clockgen", },
313 	{ .compatible = "fsl,ls2080a-clockgen", },
314 	{ .compatible = "fsl,p4080-clockgen", },
315 	{ .compatible = "fsl,qoriq-clockgen-1.0", },
316 	{ .compatible = "fsl,qoriq-clockgen-2.0", },
317 	{}
318 };
319 
320 static int __init qoriq_cpufreq_init(void)
321 {
322 	int ret;
323 	struct device_node  *np;
324 	const struct of_device_id *match;
325 	const struct soc_data *data;
326 
327 	np = of_find_matching_node(NULL, node_matches);
328 	if (!np)
329 		return -ENODEV;
330 
331 	match = of_match_node(node_matches, np);
332 	data = match->data;
333 
334 	of_node_put(np);
335 
336 	if (data && data->flags & SOC_BLACKLIST)
337 		return -ENODEV;
338 
339 	ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
340 	if (!ret)
341 		pr_info("Freescale QorIQ CPU frequency scaling driver\n");
342 
343 	return ret;
344 }
345 module_init(qoriq_cpufreq_init);
346 
347 static void __exit qoriq_cpufreq_exit(void)
348 {
349 	cpufreq_unregister_driver(&qoriq_cpufreq_driver);
350 }
351 module_exit(qoriq_cpufreq_exit);
352 
353 MODULE_LICENSE("GPL");
354 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
355 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
356