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>
25 #include <asm/smp.h> /* for get_hard_smp_processor_id() in UP configs */
28 * struct cpu_data - per CPU data struct
29 * @parent: the parent node of cpu clock
30 * @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 static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
74 /* cpumask in a cluster */
75 static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
78 static inline const struct cpumask *cpu_core_mask(int cpu)
84 /* reduce the duplicated frequencies in frequency table */
85 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
90 for (i = 1; i < count; i++) {
91 for (j = 0; j < i; j++) {
92 if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
93 freq_table[j].frequency !=
94 freq_table[i].frequency)
97 freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
103 /* sort the frequencies in frequency table in descenting order */
104 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
108 unsigned int freq, max_freq;
109 struct cpufreq_frequency_table table;
110 for (i = 0; i < count - 1; i++) {
111 max_freq = freq_table[i].frequency;
113 for (j = i + 1; j < count; j++) {
114 freq = freq_table[j].frequency;
115 if (freq == CPUFREQ_ENTRY_INVALID ||
123 /* exchange the frequencies */
124 table.driver_data = freq_table[i].driver_data;
125 table.frequency = freq_table[i].frequency;
126 freq_table[i].driver_data = freq_table[ind].driver_data;
127 freq_table[i].frequency = freq_table[ind].frequency;
128 freq_table[ind].driver_data = table.driver_data;
129 freq_table[ind].frequency = table.frequency;
134 static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
136 struct device_node *np;
140 struct cpufreq_frequency_table *table;
141 struct cpu_data *data;
142 unsigned int cpu = policy->cpu;
145 np = of_get_cpu_node(cpu, NULL);
149 data = kzalloc(sizeof(*data), GFP_KERNEL);
151 pr_err("%s: no memory\n", __func__);
155 policy->clk = of_clk_get(np, 0);
156 if (IS_ERR(policy->clk)) {
157 pr_err("%s: no clock information\n", __func__);
161 data->parent = of_parse_phandle(np, "clocks", 0);
163 pr_err("%s: could not get clock information\n", __func__);
167 count = of_property_count_strings(data->parent, "clock-names");
168 table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
170 pr_err("%s: no memory\n", __func__);
175 mask = fmask[get_hard_smp_processor_id(cpu)];
179 for (i = 0; i < count; i++) {
180 clk = of_clk_get(data->parent, i);
181 freq = clk_get_rate(clk);
183 * the clock is valid if its frequency is not masked
184 * and large than minimum allowed frequency.
186 if (freq < min_cpufreq || (mask & (1 << i)))
187 table[i].frequency = CPUFREQ_ENTRY_INVALID;
189 table[i].frequency = freq / 1000;
190 table[i].driver_data = i;
192 freq_table_redup(table, count);
193 freq_table_sort(table, count);
194 table[i].frequency = CPUFREQ_TABLE_END;
196 /* set the min and max frequency properly */
197 ret = cpufreq_table_validate_and_show(policy, table);
199 pr_err("invalid frequency table: %d\n", ret);
205 /* update ->cpus if we have cluster, no harm if not */
206 cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
207 for_each_cpu(i, per_cpu(cpu_mask, cpu))
208 per_cpu(cpu_data, i) = data;
210 /* Minimum transition latency is 12 platform clocks */
211 u64temp = 12ULL * NSEC_PER_SEC;
212 do_div(u64temp, fsl_get_sys_freq());
213 policy->cpuinfo.transition_latency = u64temp + 1;
222 of_node_put(data->parent);
224 per_cpu(cpu_data, cpu) = NULL;
232 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
234 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
237 of_node_put(data->parent);
241 for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
242 per_cpu(cpu_data, cpu) = NULL;
247 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
251 struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
253 parent = of_clk_get(data->parent, data->table[index].driver_data);
254 return clk_set_parent(policy->clk, parent);
257 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
258 .name = "ppc_cpufreq",
259 .flags = CPUFREQ_CONST_LOOPS,
260 .init = corenet_cpufreq_cpu_init,
261 .exit = __exit_p(corenet_cpufreq_cpu_exit),
262 .verify = cpufreq_generic_frequency_table_verify,
263 .target_index = corenet_cpufreq_target,
264 .get = cpufreq_generic_get,
265 .attr = cpufreq_generic_attr,
268 static const struct of_device_id node_matches[] __initdata = {
269 { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
270 { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
271 { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
272 { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
273 { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
274 { .compatible = "fsl,qoriq-clockgen-2.0", },
278 static int __init ppc_corenet_cpufreq_init(void)
281 struct device_node *np;
282 const struct of_device_id *match;
283 const struct soc_data *data;
286 np = of_find_matching_node(NULL, node_matches);
290 for_each_possible_cpu(cpu) {
291 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
293 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
296 match = of_match_node(node_matches, np);
300 fmask = data->freq_mask;
301 min_cpufreq = fsl_get_sys_freq();
303 min_cpufreq = fsl_get_sys_freq() / 2;
308 ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
310 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
315 for_each_possible_cpu(cpu)
316 free_cpumask_var(per_cpu(cpu_mask, cpu));
320 module_init(ppc_corenet_cpufreq_init);
322 static void __exit ppc_corenet_cpufreq_exit(void)
326 for_each_possible_cpu(cpu)
327 free_cpumask_var(per_cpu(cpu_mask, cpu));
329 cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
331 module_exit(ppc_corenet_cpufreq_exit);
333 MODULE_LICENSE("GPL");
334 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
335 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");