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");