cpufreq.c revision 71a157e8edca55198e808f8561dd49017a54ee34 
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
31#include <asm/hw_irq.h>
32#include <asm/io.h>
33#include <asm/prom.h>
34#include <asm/time.h>
35#include <asm/smp.h>
36
37#define SDCASR_REG		0x0100
38#define SDCASR_REG_STRIDE	0x1000
39#define SDCPWR_CFGA0_REG	0x0100
40#define SDCPWR_PWST0_REG	0x0000
41#define SDCPWR_GIZTIME_REG	0x0440
42
43/* SDCPWR_GIZTIME_REG fields */
44#define SDCPWR_GIZTIME_GR	0x80000000
45#define SDCPWR_GIZTIME_LONGLOCK	0x000000ff
46
47/* Offset of ASR registers from SDC base */
48#define SDCASR_OFFSET		0x120000
49
50static void __iomem *sdcpwr_mapbase;
51static void __iomem *sdcasr_mapbase;
52
53static DEFINE_MUTEX(pas_switch_mutex);
54
55/* Current astate, is used when waking up from power savings on
56 * one core, in case the other core has switched states during
57 * the idle time.
58 */
59static int current_astate;
60
61/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
62static struct cpufreq_frequency_table pas_freqs[] = {
63	{0,	0},
64	{1,	0},
65	{2,	0},
66	{3,	0},
67	{4,	0},
68	{0,	CPUFREQ_TABLE_END},
69};
70
71static struct freq_attr *pas_cpu_freqs_attr[] = {
72	&cpufreq_freq_attr_scaling_available_freqs,
73	NULL,
74};
75
76/*
77 * hardware specific functions
78 */
79
80static int get_astate_freq(int astate)
81{
82	u32 ret;
83	ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
84
85	return ret & 0x3f;
86}
87
88static int get_cur_astate(int cpu)
89{
90	u32 ret;
91
92	ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
93	ret = (ret >> (cpu * 4)) & 0x7;
94
95	return ret;
96}
97
98static int get_gizmo_latency(void)
99{
100	u32 giztime, ret;
101
102	giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
103
104	/* just provide the upper bound */
105	if (giztime & SDCPWR_GIZTIME_GR)
106		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
107	else
108		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
109
110	return ret;
111}
112
113static void set_astate(int cpu, unsigned int astate)
114{
115	unsigned long flags;
116
117	/* Return if called before init has run */
118	if (unlikely(!sdcasr_mapbase))
119		return;
120
121	local_irq_save(flags);
122
123	out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
124
125	local_irq_restore(flags);
126}
127
128int check_astate(void)
129{
130	return get_cur_astate(hard_smp_processor_id());
131}
132
133void restore_astate(int cpu)
134{
135	set_astate(cpu, current_astate);
136}
137
138/*
139 * cpufreq functions
140 */
141
142static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
143{
144	const u32 *max_freqp;
145	u32 max_freq;
146	int i, cur_astate;
147	struct resource res;
148	struct device_node *cpu, *dn;
149	int err = -ENODEV;
150
151	cpu = of_get_cpu_node(policy->cpu, NULL);
152
153	if (!cpu)
154		goto out;
155
156	dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
157	if (!dn)
158		dn = of_find_compatible_node(NULL, NULL,
159					     "pasemi,pwrficient-sdc");
160	if (!dn)
161		goto out;
162	err = of_address_to_resource(dn, 0, &res);
163	of_node_put(dn);
164	if (err)
165		goto out;
166	sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
167	if (!sdcasr_mapbase) {
168		err = -EINVAL;
169		goto out;
170	}
171
172	dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
173	if (!dn)
174		dn = of_find_compatible_node(NULL, NULL,
175					     "pasemi,pwrficient-gizmo");
176	if (!dn) {
177		err = -ENODEV;
178		goto out_unmap_sdcasr;
179	}
180	err = of_address_to_resource(dn, 0, &res);
181	of_node_put(dn);
182	if (err)
183		goto out_unmap_sdcasr;
184	sdcpwr_mapbase = ioremap(res.start, 0x1000);
185	if (!sdcpwr_mapbase) {
186		err = -EINVAL;
187		goto out_unmap_sdcasr;
188	}
189
190	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
191
192	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
193	if (!max_freqp) {
194		err = -EINVAL;
195		goto out_unmap_sdcpwr;
196	}
197
198	/* we need the freq in kHz */
199	max_freq = *max_freqp / 1000;
200
201	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
202	pr_debug("initializing frequency table\n");
203
204	/* initialize frequency table */
205	for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
206		pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
207		pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
208	}
209
210	policy->cpuinfo.transition_latency = get_gizmo_latency();
211
212	cur_astate = get_cur_astate(policy->cpu);
213	pr_debug("current astate is at %d\n",cur_astate);
214
215	policy->cur = pas_freqs[cur_astate].frequency;
216	cpumask_copy(policy->cpus, &cpu_online_map);
217
218	ppc_proc_freq = policy->cur * 1000ul;
219
220	cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
221
222	/* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
223	 * are set correctly
224	 */
225	return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
226
227out_unmap_sdcpwr:
228	iounmap(sdcpwr_mapbase);
229
230out_unmap_sdcasr:
231	iounmap(sdcasr_mapbase);
232out:
233	return err;
234}
235
236static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
237{
238	if (sdcasr_mapbase)
239		iounmap(sdcasr_mapbase);
240	if (sdcpwr_mapbase)
241		iounmap(sdcpwr_mapbase);
242
243	cpufreq_frequency_table_put_attr(policy->cpu);
244	return 0;
245}
246
247static int pas_cpufreq_verify(struct cpufreq_policy *policy)
248{
249	return cpufreq_frequency_table_verify(policy, pas_freqs);
250}
251
252static int pas_cpufreq_target(struct cpufreq_policy *policy,
253			      unsigned int target_freq,
254			      unsigned int relation)
255{
256	struct cpufreq_freqs freqs;
257	int pas_astate_new;
258	int i;
259
260	cpufreq_frequency_table_target(policy,
261				       pas_freqs,
262				       target_freq,
263				       relation,
264				       &pas_astate_new);
265
266	freqs.old = policy->cur;
267	freqs.new = pas_freqs[pas_astate_new].frequency;
268	freqs.cpu = policy->cpu;
269
270	mutex_lock(&pas_switch_mutex);
271	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
272
273	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
274		 policy->cpu,
275		 pas_freqs[pas_astate_new].frequency,
276		 pas_freqs[pas_astate_new].index);
277
278	current_astate = pas_astate_new;
279
280	for_each_online_cpu(i)
281		set_astate(i, pas_astate_new);
282
283	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
284	mutex_unlock(&pas_switch_mutex);
285
286	ppc_proc_freq = freqs.new * 1000ul;
287	return 0;
288}
289
290static struct cpufreq_driver pas_cpufreq_driver = {
291	.name		= "pas-cpufreq",
292	.owner		= THIS_MODULE,
293	.flags		= CPUFREQ_CONST_LOOPS,
294	.init		= pas_cpufreq_cpu_init,
295	.exit		= pas_cpufreq_cpu_exit,
296	.verify		= pas_cpufreq_verify,
297	.target		= pas_cpufreq_target,
298	.attr		= pas_cpu_freqs_attr,
299};
300
301/*
302 * module init and destoy
303 */
304
305static int __init pas_cpufreq_init(void)
306{
307	if (!of_machine_is_compatible("PA6T-1682M") &&
308	    !of_machine_is_compatible("pasemi,pwrficient"))
309		return -ENODEV;
310
311	return cpufreq_register_driver(&pas_cpufreq_driver);
312}
313
314static void __exit pas_cpufreq_exit(void)
315{
316	cpufreq_unregister_driver(&pas_cpufreq_driver);
317}
318
319module_init(pas_cpufreq_init);
320module_exit(pas_cpufreq_exit);
321
322MODULE_LICENSE("GPL");
323MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
324