2 * Copyright (C) 2007 PA Semi, Inc
4 * Authors: Egor Martovetsky <egor@pasemi.com>
5 * Olof Johansson <olof@lixom.net>
7 * Maintained by: Olof Johansson <olof@lixom.net>
9 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
10 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
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)
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.
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.
28 #include <linux/cpufreq.h>
29 #include <linux/timer.h>
30 #include <linux/module.h>
32 #include <asm/hw_irq.h>
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
44 /* SDCPWR_GIZTIME_REG fields */
45 #define SDCPWR_GIZTIME_GR 0x80000000
46 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
48 /* Offset of ASR registers from SDC base */
49 #define SDCASR_OFFSET 0x120000
51 static void __iomem *sdcpwr_mapbase;
52 static void __iomem *sdcasr_mapbase;
54 static DEFINE_MUTEX(pas_switch_mutex);
56 /* Current astate, is used when waking up from power savings on
57 * one core, in case the other core has switched states during
60 static int current_astate;
62 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
63 static struct cpufreq_frequency_table pas_freqs[] = {
69 {0, CPUFREQ_TABLE_END},
73 * hardware specific functions
76 static int get_astate_freq(int astate)
79 ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
84 static int get_cur_astate(int cpu)
88 ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
89 ret = (ret >> (cpu * 4)) & 0x7;
94 static int get_gizmo_latency(void)
98 giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
100 /* just provide the upper bound */
101 if (giztime & SDCPWR_GIZTIME_GR)
102 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
104 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
109 static void set_astate(int cpu, unsigned int astate)
113 /* Return if called before init has run */
114 if (unlikely(!sdcasr_mapbase))
117 local_irq_save(flags);
119 out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
121 local_irq_restore(flags);
124 int check_astate(void)
126 return get_cur_astate(hard_smp_processor_id());
129 void restore_astate(int cpu)
131 set_astate(cpu, current_astate);
138 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
140 const u32 *max_freqp;
144 struct device_node *cpu, *dn;
147 cpu = of_get_cpu_node(policy->cpu, NULL);
152 dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
154 dn = of_find_compatible_node(NULL, NULL,
155 "pasemi,pwrficient-sdc");
158 err = of_address_to_resource(dn, 0, &res);
162 sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
163 if (!sdcasr_mapbase) {
168 dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
170 dn = of_find_compatible_node(NULL, NULL,
171 "pasemi,pwrficient-gizmo");
174 goto out_unmap_sdcasr;
176 err = of_address_to_resource(dn, 0, &res);
179 goto out_unmap_sdcasr;
180 sdcpwr_mapbase = ioremap(res.start, 0x1000);
181 if (!sdcpwr_mapbase) {
183 goto out_unmap_sdcasr;
186 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
188 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
191 goto out_unmap_sdcpwr;
194 /* we need the freq in kHz */
195 max_freq = *max_freqp / 1000;
197 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
198 pr_debug("initializing frequency table\n");
200 /* initialize frequency table */
201 for (i=0; pas_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
202 pas_freqs[i].frequency =
203 get_astate_freq(pas_freqs[i].driver_data) * 100000;
204 pr_debug("%d: %d\n", i, pas_freqs[i].frequency);
207 cur_astate = get_cur_astate(policy->cpu);
208 pr_debug("current astate is at %d\n",cur_astate);
210 policy->cur = pas_freqs[cur_astate].frequency;
211 ppc_proc_freq = policy->cur * 1000ul;
213 return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
216 iounmap(sdcpwr_mapbase);
219 iounmap(sdcasr_mapbase);
224 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
227 * We don't support CPU hotplug. Don't unmap after the system
228 * has already made it to a running state.
230 if (system_state != SYSTEM_BOOTING)
234 iounmap(sdcasr_mapbase);
236 iounmap(sdcpwr_mapbase);
238 cpufreq_frequency_table_put_attr(policy->cpu);
242 static int pas_cpufreq_target(struct cpufreq_policy *policy,
243 unsigned int target_freq,
244 unsigned int relation)
246 struct cpufreq_freqs freqs;
250 cpufreq_frequency_table_target(policy,
256 freqs.old = policy->cur;
257 freqs.new = pas_freqs[pas_astate_new].frequency;
259 mutex_lock(&pas_switch_mutex);
260 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
262 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
264 pas_freqs[pas_astate_new].frequency,
265 pas_freqs[pas_astate_new].driver_data);
267 current_astate = pas_astate_new;
269 for_each_online_cpu(i)
270 set_astate(i, pas_astate_new);
272 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
273 mutex_unlock(&pas_switch_mutex);
275 ppc_proc_freq = freqs.new * 1000ul;
279 static struct cpufreq_driver pas_cpufreq_driver = {
280 .name = "pas-cpufreq",
281 .flags = CPUFREQ_CONST_LOOPS,
282 .init = pas_cpufreq_cpu_init,
283 .exit = pas_cpufreq_cpu_exit,
284 .verify = cpufreq_generic_frequency_table_verify,
285 .target = pas_cpufreq_target,
286 .attr = cpufreq_generic_attr,
290 * module init and destoy
293 static int __init pas_cpufreq_init(void)
295 if (!of_machine_is_compatible("PA6T-1682M") &&
296 !of_machine_is_compatible("pasemi,pwrficient"))
299 return cpufreq_register_driver(&pas_cpufreq_driver);
302 static void __exit pas_cpufreq_exit(void)
304 cpufreq_unregister_driver(&pas_cpufreq_driver);
307 module_init(pas_cpufreq_init);
308 module_exit(pas_cpufreq_exit);
310 MODULE_LICENSE("GPL");
311 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");