cpufreq.c revision 0d08a84770cb03aea24268e515342d44df8ea588 
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
36#define SDCASR_REG		0x0100
37#define SDCASR_REG_STRIDE	0x1000
38#define SDCPWR_CFGA0_REG	0x0100
39#define SDCPWR_PWST0_REG	0x0000
40#define SDCPWR_GIZTIME_REG	0x0440
41
42/* SDCPWR_GIZTIME_REG fields */
43#define SDCPWR_GIZTIME_GR	0x80000000
44#define SDCPWR_GIZTIME_LONGLOCK	0x000000ff
45
46/* Offset of ASR registers from SDC base */
47#define SDCASR_OFFSET		0x120000
48
49static void __iomem *sdcpwr_mapbase;
50static void __iomem *sdcasr_mapbase;
51
52static DEFINE_MUTEX(pas_switch_mutex);
53
54/* Current astate, is used when waking up from power savings on
55 * one core, in case the other core has switched states during
56 * the idle time.
57 */
58static int current_astate;
59
60/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
61static struct cpufreq_frequency_table pas_freqs[] = {
62	{0,	0},
63	{1,	0},
64	{2,	0},
65	{3,	0},
66	{4,	0},
67	{0,	CPUFREQ_TABLE_END},
68};
69
70static struct freq_attr *pas_cpu_freqs_attr[] = {
71	&cpufreq_freq_attr_scaling_available_freqs,
72	NULL,
73};
74
75/*
76 * hardware specific functions
77 */
78
79static int get_astate_freq(int astate)
80{
81	u32 ret;
82	ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
83
84	return ret & 0x3f;
85}
86
87static int get_cur_astate(int cpu)
88{
89	u32 ret;
90
91	ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
92	ret = (ret >> (cpu * 4)) & 0x7;
93
94	return ret;
95}
96
97static int get_gizmo_latency(void)
98{
99	u32 giztime, ret;
100
101	giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
102
103	/* just provide the upper bound */
104	if (giztime & SDCPWR_GIZTIME_GR)
105		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
106	else
107		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
108
109	return ret;
110}
111
112static void set_astate(int cpu, unsigned int astate)
113{
114	u64 flags;
115
116	/* Return if called before init has run */
117	if (unlikely(!sdcasr_mapbase))
118		return;
119
120	local_irq_save(flags);
121
122	out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
123
124	local_irq_restore(flags);
125}
126
127void restore_astate(int cpu)
128{
129	set_astate(cpu, current_astate);
130}
131
132/*
133 * cpufreq functions
134 */
135
136static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
137{
138	const u32 *max_freqp;
139	u32 max_freq;
140	int i, cur_astate;
141	struct resource res;
142	struct device_node *cpu, *dn;
143	int err = -ENODEV;
144
145	cpu = of_get_cpu_node(policy->cpu, NULL);
146
147	if (!cpu)
148		goto out;
149
150	dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
151	if (!dn)
152		dn = of_find_compatible_node(NULL, NULL,
153					     "pasemi,pwrficient-sdc");
154	if (!dn)
155		goto out;
156	err = of_address_to_resource(dn, 0, &res);
157	of_node_put(dn);
158	if (err)
159		goto out;
160	sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
161	if (!sdcasr_mapbase) {
162		err = -EINVAL;
163		goto out;
164	}
165
166	dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
167	if (!dn)
168		dn = of_find_compatible_node(NULL, NULL,
169					     "pasemi,pwrficient-gizmo");
170	if (!dn) {
171		err = -ENODEV;
172		goto out_unmap_sdcasr;
173	}
174	err = of_address_to_resource(dn, 0, &res);
175	of_node_put(dn);
176	if (err)
177		goto out_unmap_sdcasr;
178	sdcpwr_mapbase = ioremap(res.start, 0x1000);
179	if (!sdcpwr_mapbase) {
180		err = -EINVAL;
181		goto out_unmap_sdcasr;
182	}
183
184	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
185
186	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
187	if (!max_freqp) {
188		err = -EINVAL;
189		goto out_unmap_sdcpwr;
190	}
191
192	/* we need the freq in kHz */
193	max_freq = *max_freqp / 1000;
194
195	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
196	pr_debug("initializing frequency table\n");
197
198	/* initialize frequency table */
199	for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
200		pas_freqs[i].frequency = get_astate_freq(pas_freqs[i].index) * 100000;
201		pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
202	}
203
204	policy->cpuinfo.transition_latency = get_gizmo_latency();
205
206	cur_astate = get_cur_astate(policy->cpu);
207	pr_debug("current astate is at %d\n",cur_astate);
208
209	policy->cur = pas_freqs[cur_astate].frequency;
210	policy->cpus = cpu_online_map;
211
212	ppc_proc_freq = policy->cur * 1000ul;
213
214	cpufreq_frequency_table_get_attr(pas_freqs, policy->cpu);
215
216	/* this ensures that policy->cpuinfo_min and policy->cpuinfo_max
217	 * are set correctly
218	 */
219	return cpufreq_frequency_table_cpuinfo(policy, pas_freqs);
220
221out_unmap_sdcpwr:
222	iounmap(sdcpwr_mapbase);
223
224out_unmap_sdcasr:
225	iounmap(sdcasr_mapbase);
226out:
227	return err;
228}
229
230static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
231{
232	if (sdcasr_mapbase)
233		iounmap(sdcasr_mapbase);
234	if (sdcpwr_mapbase)
235		iounmap(sdcpwr_mapbase);
236
237	cpufreq_frequency_table_put_attr(policy->cpu);
238	return 0;
239}
240
241static int pas_cpufreq_verify(struct cpufreq_policy *policy)
242{
243	return cpufreq_frequency_table_verify(policy, pas_freqs);
244}
245
246static int pas_cpufreq_target(struct cpufreq_policy *policy,
247			      unsigned int target_freq,
248			      unsigned int relation)
249{
250	struct cpufreq_freqs freqs;
251	int pas_astate_new;
252	int i;
253
254	cpufreq_frequency_table_target(policy,
255				       pas_freqs,
256				       target_freq,
257				       relation,
258				       &pas_astate_new);
259
260	freqs.old = policy->cur;
261	freqs.new = pas_freqs[pas_astate_new].frequency;
262	freqs.cpu = policy->cpu;
263
264	mutex_lock(&pas_switch_mutex);
265	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
266
267	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
268		 policy->cpu,
269		 pas_freqs[pas_astate_new].frequency,
270		 pas_freqs[pas_astate_new].index);
271
272	current_astate = pas_astate_new;
273
274	for_each_online_cpu(i)
275		set_astate(i, pas_astate_new);
276
277	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
278	mutex_unlock(&pas_switch_mutex);
279
280	ppc_proc_freq = freqs.new * 1000ul;
281	return 0;
282}
283
284static struct cpufreq_driver pas_cpufreq_driver = {
285	.name		= "pas-cpufreq",
286	.owner		= THIS_MODULE,
287	.flags		= CPUFREQ_CONST_LOOPS,
288	.init		= pas_cpufreq_cpu_init,
289	.exit		= pas_cpufreq_cpu_exit,
290	.verify		= pas_cpufreq_verify,
291	.target		= pas_cpufreq_target,
292	.attr		= pas_cpu_freqs_attr,
293};
294
295/*
296 * module init and destoy
297 */
298
299static int __init pas_cpufreq_init(void)
300{
301	if (!machine_is_compatible("PA6T-1682M") &&
302	    !machine_is_compatible("pasemi,pwrficient"))
303		return -ENODEV;
304
305	return cpufreq_register_driver(&pas_cpufreq_driver);
306}
307
308static void __exit pas_cpufreq_exit(void)
309{
310	cpufreq_unregister_driver(&pas_cpufreq_driver);
311}
312
313module_init(pas_cpufreq_init);
314module_exit(pas_cpufreq_exit);
315
316MODULE_LICENSE("GPL");
317MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
318