2 * Copyright 2013 Freescale Semiconductor, Inc.
4 * CPU Frequency Scaling driver for Freescale QorIQ 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/clk-provider.h>
15 #include <linux/cpufreq.h>
16 #include <linux/errno.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>
27 * @pclk: the parent clock of cpu
28 * @table: frequency table
32 struct cpufreq_frequency_table *table;
36 * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
37 * matched a more generic compatible.
39 #define SOC_BLACKLIST 1
42 * struct soc_data - SoC specific data
49 static u32 get_bus_freq(void)
51 struct device_node *soc;
56 /* get platform freq by searching bus-frequency property */
57 soc = of_find_node_by_type(NULL, "soc");
59 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
65 /* get platform freq by its clock name */
66 pltclk = clk_get(NULL, "cg-pll0-div1");
68 pr_err("%s: can't get bus frequency %ld\n",
69 __func__, PTR_ERR(pltclk));
70 return PTR_ERR(pltclk);
73 return clk_get_rate(pltclk);
76 static struct clk *cpu_to_clk(int cpu)
78 struct device_node *np;
81 if (!cpu_present(cpu))
84 np = of_get_cpu_node(cpu, NULL);
88 clk = of_clk_get(np, 0);
93 /* traverse cpu nodes to get cpu mask of sharing clock wire */
94 static void set_affected_cpus(struct cpufreq_policy *policy)
96 struct cpumask *dstp = policy->cpus;
100 for_each_present_cpu(i) {
103 pr_err("%s: no clock for cpu %d\n", __func__, i);
107 if (clk_is_match(policy->clk, clk))
108 cpumask_set_cpu(i, dstp);
112 /* reduce the duplicated frequencies in frequency table */
113 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
118 for (i = 1; i < count; i++) {
119 for (j = 0; j < i; j++) {
120 if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
121 freq_table[j].frequency !=
122 freq_table[i].frequency)
125 freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
131 /* sort the frequencies in frequency table in descenting order */
132 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
136 unsigned int freq, max_freq;
137 struct cpufreq_frequency_table table;
139 for (i = 0; i < count - 1; i++) {
140 max_freq = freq_table[i].frequency;
142 for (j = i + 1; j < count; j++) {
143 freq = freq_table[j].frequency;
144 if (freq == CPUFREQ_ENTRY_INVALID ||
152 /* exchange the frequencies */
153 table.driver_data = freq_table[i].driver_data;
154 table.frequency = freq_table[i].frequency;
155 freq_table[i].driver_data = freq_table[ind].driver_data;
156 freq_table[i].frequency = freq_table[ind].frequency;
157 freq_table[ind].driver_data = table.driver_data;
158 freq_table[ind].frequency = table.frequency;
163 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
165 struct device_node *np;
169 const struct clk_hw *hwclk;
170 struct cpufreq_frequency_table *table;
171 struct cpu_data *data;
172 unsigned int cpu = policy->cpu;
175 np = of_get_cpu_node(cpu, NULL);
179 data = kzalloc(sizeof(*data), GFP_KERNEL);
183 policy->clk = of_clk_get(np, 0);
184 if (IS_ERR(policy->clk)) {
185 pr_err("%s: no clock information\n", __func__);
189 hwclk = __clk_get_hw(policy->clk);
190 count = clk_hw_get_num_parents(hwclk);
192 data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
196 table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
200 for (i = 0; i < count; i++) {
201 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
203 freq = clk_get_rate(clk);
204 table[i].frequency = freq / 1000;
205 table[i].driver_data = i;
207 freq_table_redup(table, count);
208 freq_table_sort(table, count);
209 table[i].frequency = CPUFREQ_TABLE_END;
210 policy->freq_table = table;
213 /* update ->cpus if we have cluster, no harm if not */
214 set_affected_cpus(policy);
215 policy->driver_data = data;
217 /* Minimum transition latency is 12 platform clocks */
218 u64temp = 12ULL * NSEC_PER_SEC;
219 do_div(u64temp, get_bus_freq());
220 policy->cpuinfo.transition_latency = u64temp + 1;
236 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
238 struct cpu_data *data = policy->driver_data;
243 policy->driver_data = NULL;
248 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
252 struct cpu_data *data = policy->driver_data;
254 parent = data->pclk[data->table[index].driver_data];
255 return clk_set_parent(policy->clk, parent);
258 static struct cpufreq_driver qoriq_cpufreq_driver = {
259 .name = "qoriq_cpufreq",
260 .flags = CPUFREQ_CONST_LOOPS |
261 CPUFREQ_IS_COOLING_DEV,
262 .init = qoriq_cpufreq_cpu_init,
263 .exit = qoriq_cpufreq_cpu_exit,
264 .verify = cpufreq_generic_frequency_table_verify,
265 .target_index = qoriq_cpufreq_target,
266 .get = cpufreq_generic_get,
267 .attr = cpufreq_generic_attr,
270 static const struct soc_data blacklist = {
271 .flags = SOC_BLACKLIST,
274 static const struct of_device_id node_matches[] __initconst = {
275 /* e6500 cannot use cpufreq due to erratum A-008083 */
276 { .compatible = "fsl,b4420-clockgen", &blacklist },
277 { .compatible = "fsl,b4860-clockgen", &blacklist },
278 { .compatible = "fsl,t2080-clockgen", &blacklist },
279 { .compatible = "fsl,t4240-clockgen", &blacklist },
281 { .compatible = "fsl,ls1012a-clockgen", },
282 { .compatible = "fsl,ls1021a-clockgen", },
283 { .compatible = "fsl,ls1028a-clockgen", },
284 { .compatible = "fsl,ls1043a-clockgen", },
285 { .compatible = "fsl,ls1046a-clockgen", },
286 { .compatible = "fsl,ls1088a-clockgen", },
287 { .compatible = "fsl,ls2080a-clockgen", },
288 { .compatible = "fsl,lx2160a-clockgen", },
289 { .compatible = "fsl,p4080-clockgen", },
290 { .compatible = "fsl,qoriq-clockgen-1.0", },
291 { .compatible = "fsl,qoriq-clockgen-2.0", },
295 static int __init qoriq_cpufreq_init(void)
298 struct device_node *np;
299 const struct of_device_id *match;
300 const struct soc_data *data;
302 np = of_find_matching_node(NULL, node_matches);
306 match = of_match_node(node_matches, np);
311 if (data && data->flags & SOC_BLACKLIST)
314 ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
316 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
320 module_init(qoriq_cpufreq_init);
322 static void __exit qoriq_cpufreq_exit(void)
324 cpufreq_unregister_driver(&qoriq_cpufreq_driver);
326 module_exit(qoriq_cpufreq_exit);
328 MODULE_LICENSE("GPL");
329 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
330 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");