1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2007 PA Semi, Inc
5 * Authors: Egor Martovetsky <egor@pasemi.com>
6 * Olof Johansson <olof@lixom.net>
8 * Maintained by: Olof Johansson <olof@lixom.net>
10 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
11 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
14 #include <linux/cpufreq.h>
15 #include <linux/timer.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
19 #include <asm/hw_irq.h>
24 #include <platforms/pasemi/pasemi.h>
26 #define SDCASR_REG 0x0100
27 #define SDCASR_REG_STRIDE 0x1000
28 #define SDCPWR_CFGA0_REG 0x0100
29 #define SDCPWR_PWST0_REG 0x0000
30 #define SDCPWR_GIZTIME_REG 0x0440
32 /* SDCPWR_GIZTIME_REG fields */
33 #define SDCPWR_GIZTIME_GR 0x80000000
34 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
36 /* Offset of ASR registers from SDC base */
37 #define SDCASR_OFFSET 0x120000
39 static void __iomem
*sdcpwr_mapbase
;
40 static void __iomem
*sdcasr_mapbase
;
42 /* Current astate, is used when waking up from power savings on
43 * one core, in case the other core has switched states during
46 static int current_astate
;
48 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
49 static struct cpufreq_frequency_table pas_freqs
[] = {
55 {0, 0, CPUFREQ_TABLE_END
},
59 * hardware specific functions
62 static int get_astate_freq(int astate
)
65 ret
= in_le32(sdcpwr_mapbase
+ SDCPWR_CFGA0_REG
+ (astate
* 0x10));
70 static int get_cur_astate(int cpu
)
74 ret
= in_le32(sdcpwr_mapbase
+ SDCPWR_PWST0_REG
);
75 ret
= (ret
>> (cpu
* 4)) & 0x7;
80 static int get_gizmo_latency(void)
84 giztime
= in_le32(sdcpwr_mapbase
+ SDCPWR_GIZTIME_REG
);
86 /* just provide the upper bound */
87 if (giztime
& SDCPWR_GIZTIME_GR
)
88 ret
= (giztime
& SDCPWR_GIZTIME_LONGLOCK
) * 128000;
90 ret
= (giztime
& SDCPWR_GIZTIME_LONGLOCK
) * 1000;
95 static void set_astate(int cpu
, unsigned int astate
)
99 /* Return if called before init has run */
100 if (unlikely(!sdcasr_mapbase
))
103 local_irq_save(flags
);
105 out_le32(sdcasr_mapbase
+ SDCASR_REG
+ SDCASR_REG_STRIDE
*cpu
, astate
);
107 local_irq_restore(flags
);
110 int check_astate(void)
112 return get_cur_astate(hard_smp_processor_id());
115 void restore_astate(int cpu
)
117 set_astate(cpu
, current_astate
);
124 static int pas_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
126 struct cpufreq_frequency_table
*pos
;
127 const u32
*max_freqp
;
131 struct device_node
*cpu
, *dn
;
134 cpu
= of_get_cpu_node(policy
->cpu
, NULL
);
138 max_freqp
= of_get_property(cpu
, "clock-frequency", NULL
);
145 /* we need the freq in kHz */
146 max_freq
= *max_freqp
/ 1000;
148 dn
= of_find_compatible_node(NULL
, NULL
, "1682m-sdc");
150 dn
= of_find_compatible_node(NULL
, NULL
,
151 "pasemi,pwrficient-sdc");
154 err
= of_address_to_resource(dn
, 0, &res
);
158 sdcasr_mapbase
= ioremap(res
.start
+ SDCASR_OFFSET
, 0x2000);
159 if (!sdcasr_mapbase
) {
164 dn
= of_find_compatible_node(NULL
, NULL
, "1682m-gizmo");
166 dn
= of_find_compatible_node(NULL
, NULL
,
167 "pasemi,pwrficient-gizmo");
170 goto out_unmap_sdcasr
;
172 err
= of_address_to_resource(dn
, 0, &res
);
175 goto out_unmap_sdcasr
;
176 sdcpwr_mapbase
= ioremap(res
.start
, 0x1000);
177 if (!sdcpwr_mapbase
) {
179 goto out_unmap_sdcasr
;
182 pr_debug("init cpufreq on CPU %d\n", policy
->cpu
);
183 pr_debug("max clock-frequency is at %u kHz\n", max_freq
);
184 pr_debug("initializing frequency table\n");
186 /* initialize frequency table */
187 cpufreq_for_each_entry_idx(pos
, pas_freqs
, idx
) {
188 pos
->frequency
= get_astate_freq(pos
->driver_data
) * 100000;
189 pr_debug("%d: %d\n", idx
, pos
->frequency
);
192 cur_astate
= get_cur_astate(policy
->cpu
);
193 pr_debug("current astate is at %d\n",cur_astate
);
195 policy
->cur
= pas_freqs
[cur_astate
].frequency
;
196 ppc_proc_freq
= policy
->cur
* 1000ul;
198 cpufreq_generic_init(policy
, pas_freqs
, get_gizmo_latency());
202 iounmap(sdcasr_mapbase
);
207 static void pas_cpufreq_cpu_exit(struct cpufreq_policy
*policy
)
210 * We don't support CPU hotplug. Don't unmap after the system
211 * has already made it to a running state.
213 if (system_state
>= SYSTEM_RUNNING
)
217 iounmap(sdcasr_mapbase
);
219 iounmap(sdcpwr_mapbase
);
222 static int pas_cpufreq_target(struct cpufreq_policy
*policy
,
223 unsigned int pas_astate_new
)
227 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
229 pas_freqs
[pas_astate_new
].frequency
,
230 pas_freqs
[pas_astate_new
].driver_data
);
232 current_astate
= pas_astate_new
;
234 for_each_online_cpu(i
)
235 set_astate(i
, pas_astate_new
);
237 ppc_proc_freq
= pas_freqs
[pas_astate_new
].frequency
* 1000ul;
241 static struct cpufreq_driver pas_cpufreq_driver
= {
242 .name
= "pas-cpufreq",
243 .flags
= CPUFREQ_CONST_LOOPS
,
244 .init
= pas_cpufreq_cpu_init
,
245 .exit
= pas_cpufreq_cpu_exit
,
246 .verify
= cpufreq_generic_frequency_table_verify
,
247 .target_index
= pas_cpufreq_target
,
248 .attr
= cpufreq_generic_attr
,
252 * module init and destoy
255 static int __init
pas_cpufreq_init(void)
257 if (!of_machine_is_compatible("PA6T-1682M") &&
258 !of_machine_is_compatible("pasemi,pwrficient"))
261 return cpufreq_register_driver(&pas_cpufreq_driver
);
264 static void __exit
pas_cpufreq_exit(void)
266 cpufreq_unregister_driver(&pas_cpufreq_driver
);
269 module_init(pas_cpufreq_init
);
270 module_exit(pas_cpufreq_exit
);
272 MODULE_DESCRIPTION("cpufreq driver for PA Semi PWRficient");
273 MODULE_LICENSE("GPL");
274 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");