1 /*
2 * Copyright (C) 2007 PA Semi, Inc
3 *
4 * Authors: Egor Martovetsky <egor@pasemi.com>
5 * Olof Johansson <olof@lixom.net>
6 *
7 * Maintained by: Olof Johansson <olof@lixom.net>
8 *
9 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
10 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2, or (at your option)
15 * any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 *
26 */
27
28 #include <linux/cpufreq.h>
29 #include <linux/timer.h>
30 #include <linux/module.h>
31
32 #include <asm/hw_irq.h>
33 #include <asm/io.h>
34 #include <asm/prom.h>
35 #include <asm/time.h>
36 #include <asm/smp.h>
37
38 #define SDCASR_REG 0x0100
39 #define SDCASR_REG_STRIDE 0x1000
40 #define SDCPWR_CFGA0_REG 0x0100
41 #define SDCPWR_PWST0_REG 0x0000
42 #define SDCPWR_GIZTIME_REG 0x0440
43
44 /* SDCPWR_GIZTIME_REG fields */
45 #define SDCPWR_GIZTIME_GR 0x80000000
46 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
47
48 /* Offset of ASR registers from SDC base */
49 #define SDCASR_OFFSET 0x120000
50
51 static void __iomem *sdcpwr_mapbase;
52 static void __iomem *sdcasr_mapbase;
53
54 static DEFINE_MUTEX(pas_switch_mutex);
55
56 /* Current astate, is used when waking up from power savings on
57 * one core, in case the other core has switched states during
58 * the idle time.
59 */
60 static int current_astate;
61
62 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
63 static struct cpufreq_frequency_table pas_freqs[] = {
64 {0, 0},
65 {1, 0},
66 {2, 0},
67 {3, 0},
68 {4, 0},
69 {0, CPUFREQ_TABLE_END},
70 };
71
72 static struct freq_attr *pas_cpu_freqs_attr[] = {
73 &cpufreq_freq_attr_scaling_available_freqs,
74 NULL,
75 };
76
77 /*
78 * hardware specific functions
79 */
80
get_astate_freq(int astate)81 static int get_astate_freq(int astate)
82 {
83 u32 ret;
84 ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
85
86 return ret & 0x3f;
87 }
88
get_cur_astate(int cpu)89 static int get_cur_astate(int cpu)
90 {
91 u32 ret;
92
93 ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
94 ret = (ret >> (cpu * 4)) & 0x7;
95
96 return ret;
97 }
98
get_gizmo_latency(void)99 static int get_gizmo_latency(void)
100 {
101 u32 giztime, ret;
102
103 giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
104
105 /* just provide the upper bound */
106 if (giztime & SDCPWR_GIZTIME_GR)
107 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
108 else
109 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
110
111 return ret;
112 }
113
set_astate(int cpu,unsigned int astate)114 static void set_astate(int cpu, unsigned int astate)
115 {
116 unsigned long flags;
117
118 /* Return if called before init has run */
119 if (unlikely(!sdcasr_mapbase))
120 return;
121
122 local_irq_save(flags);
123
124 out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
125
126 local_irq_restore(flags);
127 }
128
check_astate(void)129 int check_astate(void)
130 {
131 return get_cur_astate(hard_smp_processor_id());
132 }
133
restore_astate(int cpu)134 void restore_astate(int cpu)
135 {
136 set_astate(cpu, current_astate);
137 }
138
139 /*
140 * cpufreq functions
141 */
142
pas_cpufreq_cpu_init(struct cpufreq_policy * policy)143 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
144 {
145 const u32 *max_freqp;
146 u32 max_freq;
147 int i, cur_astate;
148 struct resource res;
149 struct device_node *cpu, *dn;
150 int err = -ENODEV;
151
152 cpu = of_get_cpu_node(policy->cpu, NULL);
153
154 if (!cpu)
155 goto out;
156
157 dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
158 if (!dn)
159 dn = of_find_compatible_node(NULL, NULL,
160 "pasemi,pwrficient-sdc");
161 if (!dn)
162 goto out;
163 err = of_address_to_resource(dn, 0, &res);
164 of_node_put(dn);
165 if (err)
166 goto out;
167 sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
168 if (!sdcasr_mapbase) {
169 err = -EINVAL;
170 goto out;
171 }
172
173 dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
174 if (!dn)
175 dn = of_find_compatible_node(NULL, NULL,
176 "pasemi,pwrficient-gizmo");
177 if (!dn) {
178 err = -ENODEV;
179 goto out_unmap_sdcasr;
180 }
181 err = of_address_to_resource(dn, 0, &res);
182 of_node_put(dn);
183 if (err)
184 goto out_unmap_sdcasr;
185 sdcpwr_mapbase = ioremap(res.start, 0x1000);
186 if (!sdcpwr_mapbase) {
187 err = -EINVAL;
188 goto out_unmap_sdcasr;
189 }
190
191 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
192
193 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
194 if (!max_freqp) {
195 err = -EINVAL;
196 goto out_unmap_sdcpwr;
197 }
198
199 /* we need the freq in kHz */
200 max_freq = *max_freqp / 1000;
201
202 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
203 pr_debug("initializing frequency table\n");
204
205 /* initialize frequency table */
206 for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
207 pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
208 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
209 }
210
211 policy->cpuinfo.transition_latency = get_gizmo_latency();
212
213 cur_astate = get_cur_astate(policy->cpu);
214 pr_debug("current astate is at %d\n",cur_astate);
215
216 policy->cur = pas_freqs[cur_astate].frequency;
217 cpumask_copy(policy->cpus, cpu_online_mask);
218
219 ppc_proc_freq = policy->cur * 1000ul;
220
221 cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
222
223 /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
224 * are set correctly
225 */
226 return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
227
228 out_unmap_sdcpwr:
229 iounmap(sdcpwr_mapbase);
230
231 out_unmap_sdcasr:
232 iounmap(sdcasr_mapbase);
233 out:
234 return err;
235 }
236
pas_cpufreq_cpu_exit(struct cpufreq_policy * policy)237 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
238 {
239 if (sdcasr_mapbase)
240 iounmap(sdcasr_mapbase);
241 if (sdcpwr_mapbase)
242 iounmap(sdcpwr_mapbase);
243
244 cpufreq_frequency_table_put_attr(policy->cpu);
245 return 0;
246 }
247
pas_cpufreq_verify(struct cpufreq_policy * policy)248 static int pas_cpufreq_verify(struct cpufreq_policy *policy)
249 {
250 return cpufreq_frequency_table_verify(policy, pas_freqs);
251 }
252
pas_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)253 static int pas_cpufreq_target(struct cpufreq_policy *policy,
254 unsigned int target_freq,
255 unsigned int relation)
256 {
257 struct cpufreq_freqs freqs;
258 int pas_astate_new;
259 int i;
260
261 cpufreq_frequency_table_target(policy,
262 pas_freqs,
263 target_freq,
264 relation,
265 &pas_astate_new);
266
267 freqs.old = policy->cur;
268 freqs.new = pas_freqs[pas_astate_new].frequency;
269 freqs.cpu = policy->cpu;
270
271 mutex_lock(&pas_switch_mutex);
272 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
273
274 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
275 policy->cpu,
276 pas_freqs[pas_astate_new].frequency,
277 pas_freqs[pas_astate_new].index);
278
279 current_astate = pas_astate_new;
280
281 for_each_online_cpu(i)
282 set_astate(i, pas_astate_new);
283
284 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
285 mutex_unlock(&pas_switch_mutex);
286
287 ppc_proc_freq = freqs.new * 1000ul;
288 return 0;
289 }
290
291 static struct cpufreq_driver pas_cpufreq_driver = {
292 .name = "pas-cpufreq",
293 .owner = THIS_MODULE,
294 .flags = CPUFREQ_CONST_LOOPS,
295 .init = pas_cpufreq_cpu_init,
296 .exit = pas_cpufreq_cpu_exit,
297 .verify = pas_cpufreq_verify,
298 .target = pas_cpufreq_target,
299 .attr = pas_cpu_freqs_attr,
300 };
301
302 /*
303 * module init and destoy
304 */
305
pas_cpufreq_init(void)306 static int __init pas_cpufreq_init(void)
307 {
308 if (!of_machine_is_compatible("PA6T-1682M") &&
309 !of_machine_is_compatible("pasemi,pwrficient"))
310 return -ENODEV;
311
312 return cpufreq_register_driver(&pas_cpufreq_driver);
313 }
314
pas_cpufreq_exit(void)315 static void __exit pas_cpufreq_exit(void)
316 {
317 cpufreq_unregister_driver(&pas_cpufreq_driver);
318 }
319
320 module_init(pas_cpufreq_init);
321 module_exit(pas_cpufreq_exit);
322
323 MODULE_LICENSE("GPL");
324 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
325