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 <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
21 #include <linux/slab.h>
22 #include <linux/smp.h>
23 #include <sysdev/fsl_soc.h>
26 * struct cpu_data - per CPU data struct
27 * @parent: the parent node of cpu clock
28 * @table: frequency table
31 struct device_node *parent;
32 struct cpufreq_frequency_table *table;
36 * struct soc_data - SoC specific data
37 * @freq_mask: mask the disallowed frequencies
46 /* see hardware specification for the allowed frqeuencies */
47 static const struct soc_data sdata[] = {
48 { /* used by p2041 and p3041 */
49 .freq_mask = {0x8, 0x8, 0x2, 0x2},
53 .freq_mask = {0x8, 0x2},
56 { /* used by p4080, p5040 */
63 * the minimum allowed core frequency, in Hz
64 * for chassis v1.0, >= platform frequency
65 * for chassis v2.0, >= platform frequency / 2
67 static u32 min_cpufreq;
68 static const u32 *fmask;
70 static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
72 /* cpumask in a cluster */
73 static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
76 static inline const struct cpumask *cpu_core_mask(int cpu)
82 /* reduce the duplicated frequencies in frequency table */
83 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
88 for (i = 1; i < count; i++) {
89 for (j = 0; j < i; j++) {
90 if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
91 freq_table[j].frequency !=
92 freq_table[i].frequency)
95 freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
101 /* sort the frequencies in frequency table in descenting order */
102 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
106 unsigned int freq, max_freq;
107 struct cpufreq_frequency_table table;
108 for (i = 0; i < count - 1; i++) {
109 max_freq = freq_table[i].frequency;
111 for (j = i + 1; j < count; j++) {
112 freq = freq_table[j].frequency;
113 if (freq == CPUFREQ_ENTRY_INVALID ||
121 /* exchange the frequencies */
122 table.driver_data = freq_table[i].driver_data;
123 table.frequency = freq_table[i].frequency;
124 freq_table[i].driver_data = freq_table[ind].driver_data;
125 freq_table[i].frequency = freq_table[ind].frequency;
126 freq_table[ind].driver_data = table.driver_data;
127 freq_table[ind].frequency = table.frequency;
132 static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
134 struct device_node *np;
138 struct cpufreq_frequency_table *table;
139 struct cpu_data *data;
140 unsigned int cpu = policy->cpu;
143 np = of_get_cpu_node(cpu, NULL);
147 data = kzalloc(sizeof(*data), GFP_KERNEL);
149 pr_err("%s: no memory\n", __func__);
153 policy->clk = of_clk_get(np, 0);
154 if (IS_ERR(policy->clk)) {
155 pr_err("%s: no clock information\n", __func__);
159 data->parent = of_parse_phandle(np, "clocks", 0);
161 pr_err("%s: could not get clock information\n", __func__);
165 count = of_property_count_strings(data->parent, "clock-names");
166 table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
168 pr_err("%s: no memory\n", __func__);
173 mask = fmask[get_hard_smp_processor_id(cpu)];
177 for (i = 0; i < count; i++) {
178 clk = of_clk_get(data->parent, i);
179 freq = clk_get_rate(clk);
181 * the clock is valid if its frequency is not masked
182 * and large than minimum allowed frequency.
184 if (freq < min_cpufreq || (mask & (1 << i)))
185 table[i].frequency = CPUFREQ_ENTRY_INVALID;
187 table[i].frequency = freq / 1000;
188 table[i].driver_data = i;
190 freq_table_redup(table, count);
191 freq_table_sort(table, count);
192 table[i].frequency = CPUFREQ_TABLE_END;
194 /* set the min and max frequency properly */
195 ret = cpufreq_table_validate_and_show(policy, table);
197 pr_err("invalid frequency table: %d\n", ret);
203 /* update ->cpus if we have cluster, no harm if not */
204 cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
205 for_each_cpu(i, per_cpu(cpu_mask, cpu))
206 per_cpu(cpu_data, i) = data;
208 /* Minimum transition latency is 12 platform clocks */
209 u64temp = 12ULL * NSEC_PER_SEC;
210 do_div(u64temp, fsl_get_sys_freq());
211 policy->cpuinfo.transition_latency = u64temp + 1;
220 of_node_put(data->parent);
222 per_cpu(cpu_data, cpu) = NULL;
230 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
232 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
235 of_node_put(data->parent);
239 for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
240 per_cpu(cpu_data, cpu) = NULL;
245 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
249 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
251 parent = of_clk_get(data->parent, data->table[index].driver_data);
252 return clk_set_parent(policy->clk, parent);
255 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
256 .name = "ppc_cpufreq",
257 .flags = CPUFREQ_CONST_LOOPS,
258 .init = corenet_cpufreq_cpu_init,
259 .exit = __exit_p(corenet_cpufreq_cpu_exit),
260 .verify = cpufreq_generic_frequency_table_verify,
261 .target_index = corenet_cpufreq_target,
262 .get = cpufreq_generic_get,
263 .attr = cpufreq_generic_attr,
266 static const struct of_device_id node_matches[] __initdata = {
267 { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
268 { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
269 { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
270 { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
271 { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
272 { .compatible = "fsl,qoriq-clockgen-2.0", },
276 static int __init ppc_corenet_cpufreq_init(void)
279 struct device_node *np;
280 const struct of_device_id *match;
281 const struct soc_data *data;
284 np = of_find_matching_node(NULL, node_matches);
288 for_each_possible_cpu(cpu) {
289 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
291 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
294 match = of_match_node(node_matches, np);
298 fmask = data->freq_mask;
299 min_cpufreq = fsl_get_sys_freq();
301 min_cpufreq = fsl_get_sys_freq() / 2;
306 ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
308 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
313 for_each_possible_cpu(cpu)
314 free_cpumask_var(per_cpu(cpu_mask, cpu));
318 module_init(ppc_corenet_cpufreq_init);
320 static void __exit ppc_corenet_cpufreq_exit(void)
324 for_each_possible_cpu(cpu)
325 free_cpumask_var(per_cpu(cpu_mask, cpu));
327 cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
329 module_exit(ppc_corenet_cpufreq_exit);
331 MODULE_LICENSE("GPL");
332 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
333 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");