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>
31 #include <linux/of_address.h>
33 #include <asm/hw_irq.h>
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
45 /* SDCPWR_GIZTIME_REG fields */
46 #define SDCPWR_GIZTIME_GR 0x80000000
47 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
49 /* Offset of ASR registers from SDC base */
50 #define SDCASR_OFFSET 0x120000
52 static void __iomem
*sdcpwr_mapbase
;
53 static void __iomem
*sdcasr_mapbase
;
55 /* Current astate, is used when waking up from power savings on
56 * one core, in case the other core has switched states during
59 static int current_astate
;
61 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
62 static struct cpufreq_frequency_table pas_freqs
[] = {
68 {0, 0, CPUFREQ_TABLE_END
},
72 * hardware specific functions
75 static int get_astate_freq(int astate
)
78 ret
= in_le32(sdcpwr_mapbase
+ SDCPWR_CFGA0_REG
+ (astate
* 0x10));
83 static int get_cur_astate(int cpu
)
87 ret
= in_le32(sdcpwr_mapbase
+ SDCPWR_PWST0_REG
);
88 ret
= (ret
>> (cpu
* 4)) & 0x7;
93 static int get_gizmo_latency(void)
97 giztime
= in_le32(sdcpwr_mapbase
+ SDCPWR_GIZTIME_REG
);
99 /* just provide the upper bound */
100 if (giztime
& SDCPWR_GIZTIME_GR
)
101 ret
= (giztime
& SDCPWR_GIZTIME_LONGLOCK
) * 128000;
103 ret
= (giztime
& SDCPWR_GIZTIME_LONGLOCK
) * 1000;
108 static void set_astate(int cpu
, unsigned int astate
)
112 /* Return if called before init has run */
113 if (unlikely(!sdcasr_mapbase
))
116 local_irq_save(flags
);
118 out_le32(sdcasr_mapbase
+ SDCASR_REG
+ SDCASR_REG_STRIDE
*cpu
, astate
);
120 local_irq_restore(flags
);
123 int check_astate(void)
125 return get_cur_astate(hard_smp_processor_id());
128 void restore_astate(int cpu
)
130 set_astate(cpu
, current_astate
);
137 static int pas_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
139 struct cpufreq_frequency_table
*pos
;
140 const u32
*max_freqp
;
144 struct device_node
*cpu
, *dn
;
147 cpu
= of_get_cpu_node(policy
->cpu
, NULL
);
151 max_freqp
= of_get_property(cpu
, "clock-frequency", NULL
);
158 /* we need the freq in kHz */
159 max_freq
= *max_freqp
/ 1000;
161 dn
= of_find_compatible_node(NULL
, NULL
, "1682m-sdc");
163 dn
= of_find_compatible_node(NULL
, NULL
,
164 "pasemi,pwrficient-sdc");
167 err
= of_address_to_resource(dn
, 0, &res
);
171 sdcasr_mapbase
= ioremap(res
.start
+ SDCASR_OFFSET
, 0x2000);
172 if (!sdcasr_mapbase
) {
177 dn
= of_find_compatible_node(NULL
, NULL
, "1682m-gizmo");
179 dn
= of_find_compatible_node(NULL
, NULL
,
180 "pasemi,pwrficient-gizmo");
183 goto out_unmap_sdcasr
;
185 err
= of_address_to_resource(dn
, 0, &res
);
188 goto out_unmap_sdcasr
;
189 sdcpwr_mapbase
= ioremap(res
.start
, 0x1000);
190 if (!sdcpwr_mapbase
) {
192 goto out_unmap_sdcasr
;
195 pr_debug("init cpufreq on CPU %d\n", policy
->cpu
);
196 pr_debug("max clock-frequency is at %u kHz\n", max_freq
);
197 pr_debug("initializing frequency table\n");
199 /* initialize frequency table */
200 cpufreq_for_each_entry_idx(pos
, pas_freqs
, idx
) {
201 pos
->frequency
= get_astate_freq(pos
->driver_data
) * 100000;
202 pr_debug("%d: %d\n", idx
, pos
->frequency
);
205 cur_astate
= get_cur_astate(policy
->cpu
);
206 pr_debug("current astate is at %d\n",cur_astate
);
208 policy
->cur
= pas_freqs
[cur_astate
].frequency
;
209 ppc_proc_freq
= policy
->cur
* 1000ul;
211 return cpufreq_generic_init(policy
, pas_freqs
, get_gizmo_latency());
214 iounmap(sdcasr_mapbase
);
219 static int pas_cpufreq_cpu_exit(struct cpufreq_policy
*policy
)
222 * We don't support CPU hotplug. Don't unmap after the system
223 * has already made it to a running state.
225 if (system_state
>= SYSTEM_RUNNING
)
229 iounmap(sdcasr_mapbase
);
231 iounmap(sdcpwr_mapbase
);
236 static int pas_cpufreq_target(struct cpufreq_policy
*policy
,
237 unsigned int pas_astate_new
)
241 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
243 pas_freqs
[pas_astate_new
].frequency
,
244 pas_freqs
[pas_astate_new
].driver_data
);
246 current_astate
= pas_astate_new
;
248 for_each_online_cpu(i
)
249 set_astate(i
, pas_astate_new
);
251 ppc_proc_freq
= pas_freqs
[pas_astate_new
].frequency
* 1000ul;
255 static struct cpufreq_driver pas_cpufreq_driver
= {
256 .name
= "pas-cpufreq",
257 .flags
= CPUFREQ_CONST_LOOPS
,
258 .init
= pas_cpufreq_cpu_init
,
259 .exit
= pas_cpufreq_cpu_exit
,
260 .verify
= cpufreq_generic_frequency_table_verify
,
261 .target_index
= pas_cpufreq_target
,
262 .attr
= cpufreq_generic_attr
,
266 * module init and destoy
269 static int __init
pas_cpufreq_init(void)
271 if (!of_machine_is_compatible("PA6T-1682M") &&
272 !of_machine_is_compatible("pasemi,pwrficient"))
275 return cpufreq_register_driver(&pas_cpufreq_driver
);
278 static void __exit
pas_cpufreq_exit(void)
280 cpufreq_unregister_driver(&pas_cpufreq_driver
);
283 module_init(pas_cpufreq_init
);
284 module_exit(pas_cpufreq_exit
);
286 MODULE_LICENSE("GPL");
287 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");