1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30 #include <sys/systm.h>
31 #include <sys/bus.h>
32 #include <sys/cpu.h>
33 #include <sys/kernel.h>
34 #include <sys/module.h>
35
36 #include "cpufreq_if.h"
37
38 struct dfs_softc {
39 device_t dev;
40 int dfs4;
41 };
42
43 static void dfs_identify(driver_t *driver, device_t parent);
44 static int dfs_probe(device_t dev);
45 static int dfs_attach(device_t dev);
46 static int dfs_settings(device_t dev, struct cf_setting *sets, int *count);
47 static int dfs_set(device_t dev, const struct cf_setting *set);
48 static int dfs_get(device_t dev, struct cf_setting *set);
49 static int dfs_type(device_t dev, int *type);
50
51 static device_method_t dfs_methods[] = {
52 /* Device interface */
53 DEVMETHOD(device_identify, dfs_identify),
54 DEVMETHOD(device_probe, dfs_probe),
55 DEVMETHOD(device_attach, dfs_attach),
56
57 /* cpufreq interface */
58 DEVMETHOD(cpufreq_drv_set, dfs_set),
59 DEVMETHOD(cpufreq_drv_get, dfs_get),
60 DEVMETHOD(cpufreq_drv_type, dfs_type),
61 DEVMETHOD(cpufreq_drv_settings, dfs_settings),
62 {0, 0}
63 };
64
65 static driver_t dfs_driver = {
66 "dfs",
67 dfs_methods,
68 sizeof(struct dfs_softc)
69 };
70
71 DRIVER_MODULE(dfs, cpu, dfs_driver, 0, 0);
72
73 /*
74 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450
75 * RISC Microprocessor Family Reference Manual", rev. 5.
76 */
77
78 #define HID1_DFS2 (1UL << 22)
79 #define HID1_DFS4 (1UL << 23)
80
81 static void
dfs_identify(driver_t * driver,device_t parent)82 dfs_identify(driver_t *driver, device_t parent)
83 {
84 uint16_t vers;
85 vers = mfpvr() >> 16;
86
87 /* Check for an MPC 7447A or 7448 CPU */
88 switch (vers) {
89 case MPC7447A:
90 case MPC7448:
91 break;
92 default:
93 return;
94 }
95
96 /* Make sure we're not being doubly invoked. */
97 if (device_find_child(parent, "dfs", -1) != NULL)
98 return;
99
100 /*
101 * We attach a child for every CPU since settings need to
102 * be performed on every CPU in the SMP case.
103 */
104 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL)
105 device_printf(parent, "add dfs child failed\n");
106 }
107
108 static int
dfs_probe(device_t dev)109 dfs_probe(device_t dev)
110 {
111 if (resource_disabled("dfs", 0))
112 return (ENXIO);
113
114 device_set_desc(dev, "Dynamic Frequency Switching");
115 return (0);
116 }
117
118 static int
dfs_attach(device_t dev)119 dfs_attach(device_t dev)
120 {
121 struct dfs_softc *sc;
122 uint16_t vers;
123
124 sc = device_get_softc(dev);
125 sc->dev = dev;
126 sc->dfs4 = 0;
127 vers = mfpvr() >> 16;
128
129 /* The 7448 supports divide-by-four as well */
130 if (vers == MPC7448)
131 sc->dfs4 = 1;
132
133 cpufreq_register(dev);
134 return (0);
135 }
136
137 static int
dfs_settings(device_t dev,struct cf_setting * sets,int * count)138 dfs_settings(device_t dev, struct cf_setting *sets, int *count)
139 {
140 struct dfs_softc *sc;
141 int states;
142
143 sc = device_get_softc(dev);
144 states = sc->dfs4 ? 3 : 2;
145 if (sets == NULL || count == NULL)
146 return (EINVAL);
147 if (*count < states)
148 return (E2BIG);
149
150 /* Return a list of valid settings for this driver. */
151 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states);
152
153 sets[0].freq = 10000; sets[0].dev = dev;
154 sets[1].freq = 5000; sets[1].dev = dev;
155 if (sc->dfs4) {
156 sets[2].freq = 2500;
157 sets[2].dev = dev;
158 }
159 *count = states;
160
161 return (0);
162 }
163
164 static int
dfs_set(device_t dev,const struct cf_setting * set)165 dfs_set(device_t dev, const struct cf_setting *set)
166 {
167 register_t hid1;
168
169 if (set == NULL)
170 return (EINVAL);
171
172 hid1 = mfspr(SPR_HID1);
173 hid1 &= ~(HID1_DFS2 | HID1_DFS4);
174
175 if (set->freq == 5000)
176 hid1 |= HID1_DFS2;
177 else if (set->freq == 2500)
178 hid1 |= HID1_DFS4;
179
180 /*
181 * Now set the HID1 register with new values. Calling sequence
182 * taken from page 2-26 of the MPC7450 family CPU manual.
183 */
184
185 powerpc_sync();
186 mtspr(SPR_HID1, hid1);
187 powerpc_sync(); isync();
188
189 return (0);
190 }
191
192 static int
dfs_get(device_t dev,struct cf_setting * set)193 dfs_get(device_t dev, struct cf_setting *set)
194 {
195 struct dfs_softc *sc;
196 register_t hid1;
197
198 if (set == NULL)
199 return (EINVAL);
200 sc = device_get_softc(dev);
201
202 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
203
204 hid1 = mfspr(SPR_HID1);
205
206 set->freq = 10000;
207 if (hid1 & HID1_DFS2)
208 set->freq = 5000;
209 else if (sc->dfs4 && (hid1 & HID1_DFS4))
210 set->freq = 2500;
211
212 set->dev = dev;
213
214 return (0);
215 }
216
217 static int
dfs_type(device_t dev,int * type)218 dfs_type(device_t dev, int *type)
219 {
220
221 if (type == NULL)
222 return (EINVAL);
223
224 *type = CPUFREQ_TYPE_RELATIVE;
225 return (0);
226 }
227