1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2007 PA Semi, Inc
4 *
5 * Authors: Egor Martovetsky <egor@pasemi.com>
6 * Olof Johansson <olof@lixom.net>
7 *
8 * Maintained by: Olof Johansson <olof@lixom.net>
9 *
10 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
11 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
12 */
13
14 #include <linux/cpufreq.h>
15 #include <linux/timer.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
18
19 #include <asm/hw_irq.h>
20 #include <asm/io.h>
21 #include <asm/prom.h>
22 #include <asm/time.h>
23 #include <asm/smp.h>
24
25 #include <platforms/pasemi/pasemi.h>
26
27 #define SDCASR_REG 0x0100
28 #define SDCASR_REG_STRIDE 0x1000
29 #define SDCPWR_CFGA0_REG 0x0100
30 #define SDCPWR_PWST0_REG 0x0000
31 #define SDCPWR_GIZTIME_REG 0x0440
32
33 /* SDCPWR_GIZTIME_REG fields */
34 #define SDCPWR_GIZTIME_GR 0x80000000
35 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
36
37 /* Offset of ASR registers from SDC base */
38 #define SDCASR_OFFSET 0x120000
39
40 static void __iomem *sdcpwr_mapbase;
41 static void __iomem *sdcasr_mapbase;
42
43 /* Current astate, is used when waking up from power savings on
44 * one core, in case the other core has switched states during
45 * the idle time.
46 */
47 static int current_astate;
48
49 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
50 static struct cpufreq_frequency_table pas_freqs[] = {
51 {0, 0, 0},
52 {0, 1, 0},
53 {0, 2, 0},
54 {0, 3, 0},
55 {0, 4, 0},
56 {0, 0, CPUFREQ_TABLE_END},
57 };
58
59 /*
60 * hardware specific functions
61 */
62
get_astate_freq(int astate)63 static int get_astate_freq(int astate)
64 {
65 u32 ret;
66 ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
67
68 return ret & 0x3f;
69 }
70
get_cur_astate(int cpu)71 static int get_cur_astate(int cpu)
72 {
73 u32 ret;
74
75 ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
76 ret = (ret >> (cpu * 4)) & 0x7;
77
78 return ret;
79 }
80
get_gizmo_latency(void)81 static int get_gizmo_latency(void)
82 {
83 u32 giztime, ret;
84
85 giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
86
87 /* just provide the upper bound */
88 if (giztime & SDCPWR_GIZTIME_GR)
89 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
90 else
91 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
92
93 return ret;
94 }
95
set_astate(int cpu,unsigned int astate)96 static void set_astate(int cpu, unsigned int astate)
97 {
98 unsigned long flags;
99
100 /* Return if called before init has run */
101 if (unlikely(!sdcasr_mapbase))
102 return;
103
104 local_irq_save(flags);
105
106 out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
107
108 local_irq_restore(flags);
109 }
110
check_astate(void)111 int check_astate(void)
112 {
113 return get_cur_astate(hard_smp_processor_id());
114 }
115
restore_astate(int cpu)116 void restore_astate(int cpu)
117 {
118 set_astate(cpu, current_astate);
119 }
120
121 /*
122 * cpufreq functions
123 */
124
pas_cpufreq_cpu_init(struct cpufreq_policy * policy)125 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
126 {
127 struct cpufreq_frequency_table *pos;
128 const u32 *max_freqp;
129 u32 max_freq;
130 int cur_astate, idx;
131 struct resource res;
132 struct device_node *cpu, *dn;
133 int err = -ENODEV;
134
135 cpu = of_get_cpu_node(policy->cpu, NULL);
136 if (!cpu)
137 goto out;
138
139 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
140 of_node_put(cpu);
141 if (!max_freqp) {
142 err = -EINVAL;
143 goto out;
144 }
145
146 /* we need the freq in kHz */
147 max_freq = *max_freqp / 1000;
148
149 dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
150 if (!dn)
151 dn = of_find_compatible_node(NULL, NULL,
152 "pasemi,pwrficient-sdc");
153 if (!dn)
154 goto out;
155 err = of_address_to_resource(dn, 0, &res);
156 of_node_put(dn);
157 if (err)
158 goto out;
159 sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
160 if (!sdcasr_mapbase) {
161 err = -EINVAL;
162 goto out;
163 }
164
165 dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
166 if (!dn)
167 dn = of_find_compatible_node(NULL, NULL,
168 "pasemi,pwrficient-gizmo");
169 if (!dn) {
170 err = -ENODEV;
171 goto out_unmap_sdcasr;
172 }
173 err = of_address_to_resource(dn, 0, &res);
174 of_node_put(dn);
175 if (err)
176 goto out_unmap_sdcasr;
177 sdcpwr_mapbase = ioremap(res.start, 0x1000);
178 if (!sdcpwr_mapbase) {
179 err = -EINVAL;
180 goto out_unmap_sdcasr;
181 }
182
183 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
184 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
185 pr_debug("initializing frequency table\n");
186
187 /* initialize frequency table */
188 cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
189 pos->frequency = get_astate_freq(pos->driver_data) * 100000;
190 pr_debug("%d: %d\n", idx, pos->frequency);
191 }
192
193 cur_astate = get_cur_astate(policy->cpu);
194 pr_debug("current astate is at %d\n",cur_astate);
195
196 policy->cur = pas_freqs[cur_astate].frequency;
197 ppc_proc_freq = policy->cur * 1000ul;
198
199 cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
200 return 0;
201
202 out_unmap_sdcasr:
203 iounmap(sdcasr_mapbase);
204 out:
205 return err;
206 }
207
pas_cpufreq_cpu_exit(struct cpufreq_policy * policy)208 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
209 {
210 /*
211 * We don't support CPU hotplug. Don't unmap after the system
212 * has already made it to a running state.
213 */
214 if (system_state >= SYSTEM_RUNNING)
215 return 0;
216
217 if (sdcasr_mapbase)
218 iounmap(sdcasr_mapbase);
219 if (sdcpwr_mapbase)
220 iounmap(sdcpwr_mapbase);
221
222 return 0;
223 }
224
pas_cpufreq_target(struct cpufreq_policy * policy,unsigned int pas_astate_new)225 static int pas_cpufreq_target(struct cpufreq_policy *policy,
226 unsigned int pas_astate_new)
227 {
228 int i;
229
230 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
231 policy->cpu,
232 pas_freqs[pas_astate_new].frequency,
233 pas_freqs[pas_astate_new].driver_data);
234
235 current_astate = pas_astate_new;
236
237 for_each_online_cpu(i)
238 set_astate(i, pas_astate_new);
239
240 ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
241 return 0;
242 }
243
244 static struct cpufreq_driver pas_cpufreq_driver = {
245 .name = "pas-cpufreq",
246 .flags = CPUFREQ_CONST_LOOPS,
247 .init = pas_cpufreq_cpu_init,
248 .exit = pas_cpufreq_cpu_exit,
249 .verify = cpufreq_generic_frequency_table_verify,
250 .target_index = pas_cpufreq_target,
251 .attr = cpufreq_generic_attr,
252 };
253
254 /*
255 * module init and destoy
256 */
257
pas_cpufreq_init(void)258 static int __init pas_cpufreq_init(void)
259 {
260 if (!of_machine_is_compatible("PA6T-1682M") &&
261 !of_machine_is_compatible("pasemi,pwrficient"))
262 return -ENODEV;
263
264 return cpufreq_register_driver(&pas_cpufreq_driver);
265 }
266
pas_cpufreq_exit(void)267 static void __exit pas_cpufreq_exit(void)
268 {
269 cpufreq_unregister_driver(&pas_cpufreq_driver);
270 }
271
272 module_init(pas_cpufreq_init);
273 module_exit(pas_cpufreq_exit);
274
275 MODULE_LICENSE("GPL");
276 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
277