2 * Copyright 2013 Freescale Semiconductor, Inc.
4 * CPU Frequency Scaling driver for Freescale PowerPC corenet SoCs.
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.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/clk.h>
14 #include <linux/cpufreq.h>
15 #include <linux/errno.h>
16 #include <sysdev/fsl_soc.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
22 #include <linux/slab.h>
23 #include <linux/smp.h>
26 * struct cpu_data - per CPU data struct
27 * @clk: the clk of CPU
28 * @parent: the parent node of cpu clock
29 * @table: frequency table
33 struct device_node *parent;
34 struct cpufreq_frequency_table *table;
38 * struct soc_data - SoC specific data
39 * @freq_mask: mask the disallowed frequencies
48 /* see hardware specification for the allowed frqeuencies */
49 static const struct soc_data sdata[] = {
50 { /* used by p2041 and p3041 */
51 .freq_mask = {0x8, 0x8, 0x2, 0x2},
55 .freq_mask = {0x8, 0x2},
58 { /* used by p4080, p5040 */
65 * the minimum allowed core frequency, in Hz
66 * for chassis v1.0, >= platform frequency
67 * for chassis v2.0, >= platform frequency / 2
69 static u32 min_cpufreq;
70 static const u32 *fmask;
72 /* serialize frequency changes */
73 static DEFINE_MUTEX(cpufreq_lock);
74 static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
76 /* cpumask in a cluster */
77 static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
80 static inline const struct cpumask *cpu_core_mask(int cpu)
86 static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
88 struct cpu_data *data = per_cpu(cpu_data, cpu);
90 return clk_get_rate(data->clk) / 1000;
93 /* reduce the duplicated frequencies in frequency table */
94 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
99 for (i = 1; i < count; i++) {
100 for (j = 0; j < i; j++) {
101 if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
102 freq_table[j].frequency !=
103 freq_table[i].frequency)
106 freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
112 /* sort the frequencies in frequency table in descenting order */
113 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
117 unsigned int freq, max_freq;
118 struct cpufreq_frequency_table table;
119 for (i = 0; i < count - 1; i++) {
120 max_freq = freq_table[i].frequency;
122 for (j = i + 1; j < count; j++) {
123 freq = freq_table[j].frequency;
124 if (freq == CPUFREQ_ENTRY_INVALID ||
132 /* exchange the frequencies */
133 table.driver_data = freq_table[i].driver_data;
134 table.frequency = freq_table[i].frequency;
135 freq_table[i].driver_data = freq_table[ind].driver_data;
136 freq_table[i].frequency = freq_table[ind].frequency;
137 freq_table[ind].driver_data = table.driver_data;
138 freq_table[ind].frequency = table.frequency;
143 static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
145 struct device_node *np;
149 struct cpufreq_frequency_table *table;
150 struct cpu_data *data;
151 unsigned int cpu = policy->cpu;
153 np = of_get_cpu_node(cpu, NULL);
157 data = kzalloc(sizeof(*data), GFP_KERNEL);
159 pr_err("%s: no memory\n", __func__);
163 data->clk = of_clk_get(np, 0);
164 if (IS_ERR(data->clk)) {
165 pr_err("%s: no clock information\n", __func__);
169 data->parent = of_parse_phandle(np, "clocks", 0);
171 pr_err("%s: could not get clock information\n", __func__);
175 count = of_property_count_strings(data->parent, "clock-names");
176 table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
178 pr_err("%s: no memory\n", __func__);
183 mask = fmask[get_hard_smp_processor_id(cpu)];
187 for (i = 0; i < count; i++) {
188 clk = of_clk_get(data->parent, i);
189 freq = clk_get_rate(clk);
191 * the clock is valid if its frequency is not masked
192 * and large than minimum allowed frequency.
194 if (freq < min_cpufreq || (mask & (1 << i)))
195 table[i].frequency = CPUFREQ_ENTRY_INVALID;
197 table[i].frequency = freq / 1000;
198 table[i].driver_data = i;
200 freq_table_redup(table, count);
201 freq_table_sort(table, count);
202 table[i].frequency = CPUFREQ_TABLE_END;
204 /* set the min and max frequency properly */
205 ret = cpufreq_frequency_table_cpuinfo(policy, table);
207 pr_err("invalid frequency table: %d\n", ret);
212 per_cpu(cpu_data, cpu) = data;
214 /* update ->cpus if we have cluster, no harm if not */
215 cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
216 for_each_cpu(i, per_cpu(cpu_mask, cpu))
217 per_cpu(cpu_data, i) = data;
219 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
220 policy->cur = corenet_cpufreq_get_speed(policy->cpu);
222 cpufreq_frequency_table_get_attr(table, cpu);
230 of_node_put(data->parent);
232 per_cpu(cpu_data, cpu) = NULL;
240 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
242 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
245 cpufreq_frequency_table_put_attr(policy->cpu);
246 of_node_put(data->parent);
250 for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
251 per_cpu(cpu_data, cpu) = NULL;
256 static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
258 struct cpufreq_frequency_table *table =
259 per_cpu(cpu_data, policy->cpu)->table;
261 return cpufreq_frequency_table_verify(policy, table);
264 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
265 unsigned int target_freq, unsigned int relation)
267 struct cpufreq_freqs freqs;
271 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
273 cpufreq_frequency_table_target(policy, data->table,
274 target_freq, relation, &new);
276 if (policy->cur == data->table[new].frequency)
279 freqs.old = policy->cur;
280 freqs.new = data->table[new].frequency;
282 mutex_lock(&cpufreq_lock);
283 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
285 parent = of_clk_get(data->parent, data->table[new].driver_data);
286 ret = clk_set_parent(data->clk, parent);
288 freqs.new = freqs.old;
290 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
291 mutex_unlock(&cpufreq_lock);
296 static struct freq_attr *corenet_cpufreq_attr[] = {
297 &cpufreq_freq_attr_scaling_available_freqs,
301 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
302 .name = "ppc_cpufreq",
303 .flags = CPUFREQ_CONST_LOOPS,
304 .init = corenet_cpufreq_cpu_init,
305 .exit = __exit_p(corenet_cpufreq_cpu_exit),
306 .verify = corenet_cpufreq_verify,
307 .target = corenet_cpufreq_target,
308 .get = corenet_cpufreq_get_speed,
309 .attr = corenet_cpufreq_attr,
312 static const struct of_device_id node_matches[] __initdata = {
313 { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
314 { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
315 { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
316 { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
317 { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
318 { .compatible = "fsl,qoriq-clockgen-2.0", },
322 static int __init ppc_corenet_cpufreq_init(void)
325 struct device_node *np;
326 const struct of_device_id *match;
327 const struct soc_data *data;
330 np = of_find_matching_node(NULL, node_matches);
334 for_each_possible_cpu(cpu) {
335 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
337 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
340 match = of_match_node(node_matches, np);
344 fmask = data->freq_mask;
345 min_cpufreq = fsl_get_sys_freq();
347 min_cpufreq = fsl_get_sys_freq() / 2;
352 ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
354 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
359 for_each_possible_cpu(cpu)
360 free_cpumask_var(per_cpu(cpu_mask, cpu));
364 module_init(ppc_corenet_cpufreq_init);
366 static void __exit ppc_corenet_cpufreq_exit(void)
370 for_each_possible_cpu(cpu)
371 free_cpumask_var(per_cpu(cpu_mask, cpu));
373 cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
375 module_exit(ppc_corenet_cpufreq_exit);
377 MODULE_LICENSE("GPL");
378 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
379 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");