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 
52 static void __iomem *sdcpwr_mapbase;
53 static 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  */
59 static int current_astate;
60 
61 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
62 static 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 
75 static 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 
83 static 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 
93 static 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 
108 static 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 
123 int check_astate(void)
124 {
125 	return get_cur_astate(hard_smp_processor_id());
126 }
127 
128 void restore_astate(int cpu)
129 {
130 	set_astate(cpu, current_astate);
131 }
132 
133 /*
134  * cpufreq functions
135  */
136 
137 static 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 
214 out_unmap_sdcpwr:
215 	iounmap(sdcpwr_mapbase);
216 
217 out_unmap_sdcasr:
218 	iounmap(sdcasr_mapbase);
219 out:
220 	return err;
221 }
222 
223 static 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 
240 static 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 
259 static 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 
273 static 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 
282 static void __exit pas_cpufreq_exit(void)
283 {
284 	cpufreq_unregister_driver(&pas_cpufreq_driver);
285 }
286 
287 module_init(pas_cpufreq_init);
288 module_exit(pas_cpufreq_exit);
289 
290 MODULE_LICENSE("GPL");
291 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
292