1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2009 Nathan Whitehorn
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/cpu.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
38
39 #include "cpufreq_if.h"
40
41 struct dfs_softc {
42 device_t dev;
43 int dfs4;
44 };
45
46 static void dfs_identify(driver_t *driver, device_t parent);
47 static int dfs_probe(device_t dev);
48 static int dfs_attach(device_t dev);
49 static int dfs_settings(device_t dev, struct cf_setting *sets, int *count);
50 static int dfs_set(device_t dev, const struct cf_setting *set);
51 static int dfs_get(device_t dev, struct cf_setting *set);
52 static int dfs_type(device_t dev, int *type);
53
54 static device_method_t dfs_methods[] = {
55 /* Device interface */
56 DEVMETHOD(device_identify, dfs_identify),
57 DEVMETHOD(device_probe, dfs_probe),
58 DEVMETHOD(device_attach, dfs_attach),
59
60 /* cpufreq interface */
61 DEVMETHOD(cpufreq_drv_set, dfs_set),
62 DEVMETHOD(cpufreq_drv_get, dfs_get),
63 DEVMETHOD(cpufreq_drv_type, dfs_type),
64 DEVMETHOD(cpufreq_drv_settings, dfs_settings),
65
66 {0, 0}
67 };
68
69 static driver_t dfs_driver = {
70 "dfs",
71 dfs_methods,
72 sizeof(struct dfs_softc)
73 };
74
75 static devclass_t dfs_devclass;
76 DRIVER_MODULE(dfs, cpu, dfs_driver, dfs_devclass, 0, 0);
77
78 /*
79 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450
80 * RISC Microprocessor Family Reference Manual", rev. 5.
81 */
82
83 #define HID1_DFS2 (1UL << 22)
84 #define HID1_DFS4 (1UL << 23)
85
86 static void
87 dfs_identify(driver_t *driver, device_t parent)
88 {
89 uint16_t vers;
90 vers = mfpvr() >> 16;
91
92 /* Check for an MPC 7447A or 7448 CPU */
93 switch (vers) {
94 case MPC7447A:
95 case MPC7448:
96 break;
97 default:
98 return;
99 }
100
101 /* Make sure we're not being doubly invoked. */
102 if (device_find_child(parent, "dfs", -1) != NULL)
103 return;
104
105 /*
106 * We attach a child for every CPU since settings need to
107 * be performed on every CPU in the SMP case.
108 */
109 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL)
110 device_printf(parent, "add dfs child failed\n");
111 }
112
113 static int
114 dfs_probe(device_t dev)
115 {
116 if (resource_disabled("dfs", 0))
117 return (ENXIO);
118
119 device_set_desc(dev, "Dynamic Frequency Switching");
120 return (0);
121 }
122
123 static int
124 dfs_attach(device_t dev)
125 {
126 struct dfs_softc *sc;
127 uint16_t vers;
128
129 sc = device_get_softc(dev);
130 sc->dev = dev;
131 sc->dfs4 = 0;
132 vers = mfpvr() >> 16;
133
134 /* The 7448 supports divide-by-four as well */
135 if (vers == MPC7448)
136 sc->dfs4 = 1;
137
138 cpufreq_register(dev);
139 return (0);
140 }
141
142 static int
143 dfs_settings(device_t dev, struct cf_setting *sets, int *count)
144 {
145 struct dfs_softc *sc;
146 int states;
147
148 sc = device_get_softc(dev);
149 states = sc->dfs4 ? 3 : 2;
150 if (sets == NULL || count == NULL)
151 return (EINVAL);
152 if (*count < states)
153 return (E2BIG);
154
155 /* Return a list of valid settings for this driver. */
156 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states);
157
158 sets[0].freq = 10000; sets[0].dev = dev;
159 sets[1].freq = 5000; sets[1].dev = dev;
160 if (sc->dfs4) {
161 sets[2].freq = 2500;
162 sets[2].dev = dev;
163 }
164 *count = states;
165
166 return (0);
167 }
168
169 static int
170 dfs_set(device_t dev, const struct cf_setting *set)
171 {
172 register_t hid1;
173
174 if (set == NULL)
175 return (EINVAL);
176
177 hid1 = mfspr(SPR_HID1);
178 hid1 &= ~(HID1_DFS2 | HID1_DFS4);
179
180 if (set->freq == 5000)
181 hid1 |= HID1_DFS2;
182 else if (set->freq == 2500)
183 hid1 |= HID1_DFS4;
184
185 /*
186 * Now set the HID1 register with new values. Calling sequence
187 * taken from page 2-26 of the MPC7450 family CPU manual.
188 */
189
190 powerpc_sync();
191 mtspr(SPR_HID1, hid1);
192 powerpc_sync(); isync();
193
194 return (0);
195 }
196
197 static int
198 dfs_get(device_t dev, struct cf_setting *set)
199 {
200 struct dfs_softc *sc;
201 register_t hid1;
202
203 if (set == NULL)
204 return (EINVAL);
205 sc = device_get_softc(dev);
206
207 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
208
209 hid1 = mfspr(SPR_HID1);
210
211 set->freq = 10000;
212 if (hid1 & HID1_DFS2)
213 set->freq = 5000;
214 else if (sc->dfs4 && (hid1 & HID1_DFS4))
215 set->freq = 2500;
216
217 set->dev = dev;
218
219 return (0);
220 }
221
222 static int
223 dfs_type(device_t dev, int *type)
224 {
225
226 if (type == NULL)
227 return (EINVAL);
228
229 *type = CPUFREQ_TYPE_RELATIVE;
230 return (0);
231 }
232
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