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 	struct clk *pltclk;
56 	int ret;
57 
58 	/* get platform freq by searching bus-frequency property */
59 	soc = of_find_node_by_type(NULL, "soc");
60 	if (soc) {
61 		ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
62 		of_node_put(soc);
63 		if (!ret)
64 			return sysfreq;
65 	}
66 
67 	/* get platform freq by its clock name */
68 	pltclk = clk_get(NULL, "cg-pll0-div1");
69 	if (IS_ERR(pltclk)) {
70 		pr_err("%s: can't get bus frequency %ld\n",
71 		       __func__, PTR_ERR(pltclk));
72 		return PTR_ERR(pltclk);
73 	}
74 
75 	return clk_get_rate(pltclk);
76 }
77 
78 static struct clk *cpu_to_clk(int cpu)
79 {
80 	struct device_node *np;
81 	struct clk *clk;
82 
83 	if (!cpu_present(cpu))
84 		return NULL;
85 
86 	np = of_get_cpu_node(cpu, NULL);
87 	if (!np)
88 		return NULL;
89 
90 	clk = of_clk_get(np, 0);
91 	of_node_put(np);
92 	return clk;
93 }
94 
95 /* traverse cpu nodes to get cpu mask of sharing clock wire */
96 static void set_affected_cpus(struct cpufreq_policy *policy)
97 {
98 	struct cpumask *dstp = policy->cpus;
99 	struct clk *clk;
100 	int i;
101 
102 	for_each_present_cpu(i) {
103 		clk = cpu_to_clk(i);
104 		if (IS_ERR(clk)) {
105 			pr_err("%s: no clock for cpu %d\n", __func__, i);
106 			continue;
107 		}
108 
109 		if (clk_is_match(policy->clk, clk))
110 			cpumask_set_cpu(i, dstp);
111 	}
112 }
113 
114 /* reduce the duplicated frequencies in frequency table */
115 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
116 		int count)
117 {
118 	int i, j;
119 
120 	for (i = 1; i < count; i++) {
121 		for (j = 0; j < i; j++) {
122 			if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
123 					freq_table[j].frequency !=
124 					freq_table[i].frequency)
125 				continue;
126 
127 			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
128 			break;
129 		}
130 	}
131 }
132 
133 /* sort the frequencies in frequency table in descenting order */
134 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
135 		int count)
136 {
137 	int i, j, ind;
138 	unsigned int freq, max_freq;
139 	struct cpufreq_frequency_table table;
140 
141 	for (i = 0; i < count - 1; i++) {
142 		max_freq = freq_table[i].frequency;
143 		ind = i;
144 		for (j = i + 1; j < count; j++) {
145 			freq = freq_table[j].frequency;
146 			if (freq == CPUFREQ_ENTRY_INVALID ||
147 					freq <= max_freq)
148 				continue;
149 			ind = j;
150 			max_freq = freq;
151 		}
152 
153 		if (ind != i) {
154 			/* exchange the frequencies */
155 			table.driver_data = freq_table[i].driver_data;
156 			table.frequency = freq_table[i].frequency;
157 			freq_table[i].driver_data = freq_table[ind].driver_data;
158 			freq_table[i].frequency = freq_table[ind].frequency;
159 			freq_table[ind].driver_data = table.driver_data;
160 			freq_table[ind].frequency = table.frequency;
161 		}
162 	}
163 }
164 
165 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
166 {
167 	struct device_node *np;
168 	int i, count, ret;
169 	u32 freq;
170 	struct clk *clk;
171 	const struct clk_hw *hwclk;
172 	struct cpufreq_frequency_table *table;
173 	struct cpu_data *data;
174 	unsigned int cpu = policy->cpu;
175 	u64 u64temp;
176 
177 	np = of_get_cpu_node(cpu, NULL);
178 	if (!np)
179 		return -ENODEV;
180 
181 	data = kzalloc(sizeof(*data), GFP_KERNEL);
182 	if (!data)
183 		goto err_np;
184 
185 	policy->clk = of_clk_get(np, 0);
186 	if (IS_ERR(policy->clk)) {
187 		pr_err("%s: no clock information\n", __func__);
188 		goto err_nomem2;
189 	}
190 
191 	hwclk = __clk_get_hw(policy->clk);
192 	count = clk_hw_get_num_parents(hwclk);
193 
194 	data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
195 	if (!data->pclk) {
196 		pr_err("%s: no memory\n", __func__);
197 		goto err_nomem2;
198 	}
199 
200 	table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
201 	if (!table) {
202 		pr_err("%s: no memory\n", __func__);
203 		goto err_pclk;
204 	}
205 
206 	for (i = 0; i < count; i++) {
207 		clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
208 		data->pclk[i] = clk;
209 		freq = clk_get_rate(clk);
210 		table[i].frequency = freq / 1000;
211 		table[i].driver_data = i;
212 	}
213 	freq_table_redup(table, count);
214 	freq_table_sort(table, count);
215 	table[i].frequency = CPUFREQ_TABLE_END;
216 
217 	/* set the min and max frequency properly */
218 	ret = cpufreq_table_validate_and_show(policy, table);
219 	if (ret) {
220 		pr_err("invalid frequency table: %d\n", ret);
221 		goto err_nomem1;
222 	}
223 
224 	data->table = table;
225 
226 	/* update ->cpus if we have cluster, no harm if not */
227 	set_affected_cpus(policy);
228 	policy->driver_data = data;
229 
230 	/* Minimum transition latency is 12 platform clocks */
231 	u64temp = 12ULL * NSEC_PER_SEC;
232 	do_div(u64temp, get_bus_freq());
233 	policy->cpuinfo.transition_latency = u64temp + 1;
234 
235 	of_node_put(np);
236 
237 	return 0;
238 
239 err_nomem1:
240 	kfree(table);
241 err_pclk:
242 	kfree(data->pclk);
243 err_nomem2:
244 	kfree(data);
245 err_np:
246 	of_node_put(np);
247 
248 	return -ENODEV;
249 }
250 
251 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
252 {
253 	struct cpu_data *data = policy->driver_data;
254 
255 	cpufreq_cooling_unregister(data->cdev);
256 	kfree(data->pclk);
257 	kfree(data->table);
258 	kfree(data);
259 	policy->driver_data = NULL;
260 
261 	return 0;
262 }
263 
264 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
265 		unsigned int index)
266 {
267 	struct clk *parent;
268 	struct cpu_data *data = policy->driver_data;
269 
270 	parent = data->pclk[data->table[index].driver_data];
271 	return clk_set_parent(policy->clk, parent);
272 }
273 
274 
275 static void qoriq_cpufreq_ready(struct cpufreq_policy *policy)
276 {
277 	struct cpu_data *cpud = policy->driver_data;
278 	struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
279 
280 	if (of_find_property(np, "#cooling-cells", NULL)) {
281 		cpud->cdev = of_cpufreq_cooling_register(np, policy);
282 
283 		if (IS_ERR(cpud->cdev) && PTR_ERR(cpud->cdev) != -ENOSYS) {
284 			pr_err("cpu%d is not running as cooling device: %ld\n",
285 					policy->cpu, PTR_ERR(cpud->cdev));
286 
287 			cpud->cdev = NULL;
288 		}
289 	}
290 
291 	of_node_put(np);
292 }
293 
294 static struct cpufreq_driver qoriq_cpufreq_driver = {
295 	.name		= "qoriq_cpufreq",
296 	.flags		= CPUFREQ_CONST_LOOPS,
297 	.init		= qoriq_cpufreq_cpu_init,
298 	.exit		= qoriq_cpufreq_cpu_exit,
299 	.verify		= cpufreq_generic_frequency_table_verify,
300 	.target_index	= qoriq_cpufreq_target,
301 	.get		= cpufreq_generic_get,
302 	.ready		= qoriq_cpufreq_ready,
303 	.attr		= cpufreq_generic_attr,
304 };
305 
306 static const struct soc_data blacklist = {
307 	.flags = SOC_BLACKLIST,
308 };
309 
310 static const struct of_device_id node_matches[] __initconst = {
311 	/* e6500 cannot use cpufreq due to erratum A-008083 */
312 	{ .compatible = "fsl,b4420-clockgen", &blacklist },
313 	{ .compatible = "fsl,b4860-clockgen", &blacklist },
314 	{ .compatible = "fsl,t2080-clockgen", &blacklist },
315 	{ .compatible = "fsl,t4240-clockgen", &blacklist },
316 
317 	{ .compatible = "fsl,ls1012a-clockgen", },
318 	{ .compatible = "fsl,ls1021a-clockgen", },
319 	{ .compatible = "fsl,ls1043a-clockgen", },
320 	{ .compatible = "fsl,ls1046a-clockgen", },
321 	{ .compatible = "fsl,ls1088a-clockgen", },
322 	{ .compatible = "fsl,ls2080a-clockgen", },
323 	{ .compatible = "fsl,p4080-clockgen", },
324 	{ .compatible = "fsl,qoriq-clockgen-1.0", },
325 	{ .compatible = "fsl,qoriq-clockgen-2.0", },
326 	{}
327 };
328 
329 static int __init qoriq_cpufreq_init(void)
330 {
331 	int ret;
332 	struct device_node  *np;
333 	const struct of_device_id *match;
334 	const struct soc_data *data;
335 
336 	np = of_find_matching_node(NULL, node_matches);
337 	if (!np)
338 		return -ENODEV;
339 
340 	match = of_match_node(node_matches, np);
341 	data = match->data;
342 
343 	of_node_put(np);
344 
345 	if (data && data->flags & SOC_BLACKLIST)
346 		return -ENODEV;
347 
348 	ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
349 	if (!ret)
350 		pr_info("Freescale QorIQ CPU frequency scaling driver\n");
351 
352 	return ret;
353 }
354 module_init(qoriq_cpufreq_init);
355 
356 static void __exit qoriq_cpufreq_exit(void)
357 {
358 	cpufreq_unregister_driver(&qoriq_cpufreq_driver);
359 }
360 module_exit(qoriq_cpufreq_exit);
361 
362 MODULE_LICENSE("GPL");
363 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
364 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
365