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