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/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/cpu.h>
34 #include <sys/kernel.h>
35 #include <sys/module.h>
36
37 #include "cpufreq_if.h"
38
39 struct dfs_softc {
40 device_t dev;
41 int dfs4;
42 };
43
44 static void dfs_identify(driver_t *driver, device_t parent);
45 static int dfs_probe(device_t dev);
46 static int dfs_attach(device_t dev);
47 static int dfs_settings(device_t dev, struct cf_setting *sets, int *count);
48 static int dfs_set(device_t dev, const struct cf_setting *set);
49 static int dfs_get(device_t dev, struct cf_setting *set);
50 static int dfs_type(device_t dev, int *type);
51
52 static device_method_t dfs_methods[] = {
53 /* Device interface */
54 DEVMETHOD(device_identify, dfs_identify),
55 DEVMETHOD(device_probe, dfs_probe),
56 DEVMETHOD(device_attach, dfs_attach),
57
58 /* cpufreq interface */
59 DEVMETHOD(cpufreq_drv_set, dfs_set),
60 DEVMETHOD(cpufreq_drv_get, dfs_get),
61 DEVMETHOD(cpufreq_drv_type, dfs_type),
62 DEVMETHOD(cpufreq_drv_settings, dfs_settings),
63 {0, 0}
64 };
65
66 static driver_t dfs_driver = {
67 "dfs",
68 dfs_methods,
69 sizeof(struct dfs_softc)
70 };
71
72 DRIVER_MODULE(dfs, cpu, dfs_driver, 0, 0);
73
74 /*
75 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450
76 * RISC Microprocessor Family Reference Manual", rev. 5.
77 */
78
79 #define HID1_DFS2 (1UL << 22)
80 #define HID1_DFS4 (1UL << 23)
81
82 static void
dfs_identify(driver_t * driver,device_t parent)83 dfs_identify(driver_t *driver, device_t parent)
84 {
85 uint16_t vers;
86 vers = mfpvr() >> 16;
87
88 /* Check for an MPC 7447A or 7448 CPU */
89 switch (vers) {
90 case MPC7447A:
91 case MPC7448:
92 break;
93 default:
94 return;
95 }
96
97 /* Make sure we're not being doubly invoked. */
98 if (device_find_child(parent, "dfs", -1) != NULL)
99 return;
100
101 /*
102 * We attach a child for every CPU since settings need to
103 * be performed on every CPU in the SMP case.
104 */
105 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL)
106 device_printf(parent, "add dfs child failed\n");
107 }
108
109 static int
dfs_probe(device_t dev)110 dfs_probe(device_t dev)
111 {
112 if (resource_disabled("dfs", 0))
113 return (ENXIO);
114
115 device_set_desc(dev, "Dynamic Frequency Switching");
116 return (0);
117 }
118
119 static int
dfs_attach(device_t dev)120 dfs_attach(device_t dev)
121 {
122 struct dfs_softc *sc;
123 uint16_t vers;
124
125 sc = device_get_softc(dev);
126 sc->dev = dev;
127 sc->dfs4 = 0;
128 vers = mfpvr() >> 16;
129
130 /* The 7448 supports divide-by-four as well */
131 if (vers == MPC7448)
132 sc->dfs4 = 1;
133
134 cpufreq_register(dev);
135 return (0);
136 }
137
138 static int
dfs_settings(device_t dev,struct cf_setting * sets,int * count)139 dfs_settings(device_t dev, struct cf_setting *sets, int *count)
140 {
141 struct dfs_softc *sc;
142 int states;
143
144 sc = device_get_softc(dev);
145 states = sc->dfs4 ? 3 : 2;
146 if (sets == NULL || count == NULL)
147 return (EINVAL);
148 if (*count < states)
149 return (E2BIG);
150
151 /* Return a list of valid settings for this driver. */
152 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states);
153
154 sets[0].freq = 10000; sets[0].dev = dev;
155 sets[1].freq = 5000; sets[1].dev = dev;
156 if (sc->dfs4) {
157 sets[2].freq = 2500;
158 sets[2].dev = dev;
159 }
160 *count = states;
161
162 return (0);
163 }
164
165 static int
dfs_set(device_t dev,const struct cf_setting * set)166 dfs_set(device_t dev, const struct cf_setting *set)
167 {
168 register_t hid1;
169
170 if (set == NULL)
171 return (EINVAL);
172
173 hid1 = mfspr(SPR_HID1);
174 hid1 &= ~(HID1_DFS2 | HID1_DFS4);
175
176 if (set->freq == 5000)
177 hid1 |= HID1_DFS2;
178 else if (set->freq == 2500)
179 hid1 |= HID1_DFS4;
180
181 /*
182 * Now set the HID1 register with new values. Calling sequence
183 * taken from page 2-26 of the MPC7450 family CPU manual.
184 */
185
186 powerpc_sync();
187 mtspr(SPR_HID1, hid1);
188 powerpc_sync(); isync();
189
190 return (0);
191 }
192
193 static int
dfs_get(device_t dev,struct cf_setting * set)194 dfs_get(device_t dev, struct cf_setting *set)
195 {
196 struct dfs_softc *sc;
197 register_t hid1;
198
199 if (set == NULL)
200 return (EINVAL);
201 sc = device_get_softc(dev);
202
203 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
204
205 hid1 = mfspr(SPR_HID1);
206
207 set->freq = 10000;
208 if (hid1 & HID1_DFS2)
209 set->freq = 5000;
210 else if (sc->dfs4 && (hid1 & HID1_DFS4))
211 set->freq = 2500;
212
213 set->dev = dev;
214
215 return (0);
216 }
217
218 static int
dfs_type(device_t dev,int * type)219 dfs_type(device_t dev, int *type)
220 {
221
222 if (type == NULL)
223 return (EINVAL);
224
225 *type = CPUFREQ_TYPE_RELATIVE;
226 return (0);
227 }
228