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#include <linux/of_address.h>
 32
 33#include <asm/hw_irq.h>
 34#include <asm/io.h>
 35#include <asm/prom.h>
 36#include <asm/time.h>
 37#include <asm/smp.h>
 38
 39#define SDCASR_REG		0x0100
 40#define SDCASR_REG_STRIDE	0x1000
 41#define SDCPWR_CFGA0_REG	0x0100
 42#define SDCPWR_PWST0_REG	0x0000
 43#define SDCPWR_GIZTIME_REG	0x0440
 44
 45/* SDCPWR_GIZTIME_REG fields */
 46#define SDCPWR_GIZTIME_GR	0x80000000
 47#define SDCPWR_GIZTIME_LONGLOCK	0x000000ff
 48
 49/* Offset of ASR registers from SDC base */
 50#define SDCASR_OFFSET		0x120000
 51
 52static void __iomem *sdcpwr_mapbase;
 53static void __iomem *sdcasr_mapbase;
 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,	0},
 64	{0, 1,	0},
 65	{0, 2,	0},
 66	{0, 3,	0},
 67	{0, 4,	0},
 68	{0, 0,	CPUFREQ_TABLE_END},
 69};
 70
 71/*
 72 * hardware specific functions
 73 */
 74
 75static int get_astate_freq(int astate)
 76{
 77	u32 ret;
 78	ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
 79
 80	return ret & 0x3f;
 81}
 82
 83static int get_cur_astate(int cpu)
 84{
 85	u32 ret;
 86
 87	ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
 88	ret = (ret >> (cpu * 4)) & 0x7;
 89
 90	return ret;
 91}
 92
 93static int get_gizmo_latency(void)
 94{
 95	u32 giztime, ret;
 96
 97	giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 98
 99	/* just provide the upper bound */
100	if (giztime & SDCPWR_GIZTIME_GR)
101		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
102	else
103		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
104
105	return ret;
106}
107
108static void set_astate(int cpu, unsigned int astate)
109{
110	unsigned long flags;
111
112	/* Return if called before init has run */
113	if (unlikely(!sdcasr_mapbase))
114		return;
115
116	local_irq_save(flags);
117
118	out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
119
120	local_irq_restore(flags);
121}
122
123int check_astate(void)
124{
125	return get_cur_astate(hard_smp_processor_id());
126}
127
128void restore_astate(int cpu)
129{
130	set_astate(cpu, current_astate);
131}
132
133/*
134 * cpufreq functions
135 */
136
137static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
138{
139	const u32 *max_freqp;
140	u32 max_freq;
141	int i, cur_astate;
142	struct resource res;
143	struct device_node *cpu, *dn;
144	int err = -ENODEV;
145
146	cpu = of_get_cpu_node(policy->cpu, NULL);
147
148	if (!cpu)
149		goto out;
150
151	dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
152	if (!dn)
153		dn = of_find_compatible_node(NULL, NULL,
154					     "pasemi,pwrficient-sdc");
155	if (!dn)
156		goto out;
157	err = of_address_to_resource(dn, 0, &res);
158	of_node_put(dn);
159	if (err)
160		goto out;
161	sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
162	if (!sdcasr_mapbase) {
163		err = -EINVAL;
164		goto out;
165	}
166
167	dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
168	if (!dn)
169		dn = of_find_compatible_node(NULL, NULL,
170					     "pasemi,pwrficient-gizmo");
171	if (!dn) {
172		err = -ENODEV;
173		goto out_unmap_sdcasr;
174	}
175	err = of_address_to_resource(dn, 0, &res);
176	of_node_put(dn);
177	if (err)
178		goto out_unmap_sdcasr;
179	sdcpwr_mapbase = ioremap(res.start, 0x1000);
180	if (!sdcpwr_mapbase) {
181		err = -EINVAL;
182		goto out_unmap_sdcasr;
183	}
184
185	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
186
187	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
188	if (!max_freqp) {
189		err = -EINVAL;
190		goto out_unmap_sdcpwr;
191	}
192
193	/* we need the freq in kHz */
194	max_freq = *max_freqp / 1000;
195
196	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
197	pr_debug("initializing frequency table\n");
198
199	/* initialize frequency table */
200	for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
201		pas_freqs[i].frequency =
202			get_astate_freq(pas_freqs[i].driver_data) * 100000;
203		pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
204	}
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	ppc_proc_freq = policy->cur * 1000ul;
211
212	return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
213
214out_unmap_sdcpwr:
215	iounmap(sdcpwr_mapbase);
216
217out_unmap_sdcasr:
218	iounmap(sdcasr_mapbase);
219out:
220	return err;
221}
222
223static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
224{
225	/*
226	 * We don't support CPU hotplug. Don't unmap after the system
227	 * has already made it to a running state.
228	 */
229	if (system_state != SYSTEM_BOOTING)
230		return 0;
231
232	if (sdcasr_mapbase)
233		iounmap(sdcasr_mapbase);
234	if (sdcpwr_mapbase)
235		iounmap(sdcpwr_mapbase);
236
237	return 0;
238}
239
240static int pas_cpufreq_target(struct cpufreq_policy *policy,
241			      unsigned int pas_astate_new)
242{
243	int i;
244
245	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
246		 policy->cpu,
247		 pas_freqs[pas_astate_new].frequency,
248		 pas_freqs[pas_astate_new].driver_data);
249
250	current_astate = pas_astate_new;
251
252	for_each_online_cpu(i)
253		set_astate(i, pas_astate_new);
254
255	ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
256	return 0;
257}
258
259static struct cpufreq_driver pas_cpufreq_driver = {
260	.name		= "pas-cpufreq",
261	.flags		= CPUFREQ_CONST_LOOPS,
262	.init		= pas_cpufreq_cpu_init,
263	.exit		= pas_cpufreq_cpu_exit,
264	.verify		= cpufreq_generic_frequency_table_verify,
265	.target_index	= pas_cpufreq_target,
266	.attr		= cpufreq_generic_attr,
267};
268
269/*
270 * module init and destoy
271 */
272
273static int __init pas_cpufreq_init(void)
274{
275	if (!of_machine_is_compatible("PA6T-1682M") &&
276	    !of_machine_is_compatible("pasemi,pwrficient"))
277		return -ENODEV;
278
279	return cpufreq_register_driver(&pas_cpufreq_driver);
280}
281
282static void __exit pas_cpufreq_exit(void)
283{
284	cpufreq_unregister_driver(&pas_cpufreq_driver);
285}
286
287module_init(pas_cpufreq_init);
288module_exit(pas_cpufreq_exit);
289
290MODULE_LICENSE("GPL");
291MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");