1 /*-
2 * Copyright (c) 2009 Nathan Whitehorn
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
19 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
21 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
22 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: stable/10/sys/powerpc/cpufreq/dfs.c 217065 2011-01-06 20:19:01Z andreast $");
29
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
64 {0, 0}
65 };
66
67 static driver_t dfs_driver = {
68 "dfs",
69 dfs_methods,
70 sizeof(struct dfs_softc)
71 };
72
73 static devclass_t dfs_devclass;
74 DRIVER_MODULE(dfs, cpu, dfs_driver, dfs_devclass, 0, 0);
75
76 /*
77 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450
78 * RISC Microprocessor Family Reference Manual", rev. 5.
79 */
80
81 #define HID1_DFS2 (1UL << 22)
82 #define HID1_DFS4 (1UL << 23)
83
84 static void
dfs_identify(driver_t * driver,device_t parent)85 dfs_identify(driver_t *driver, device_t parent)
86 {
87 uint16_t vers;
88 vers = mfpvr() >> 16;
89
90 /* Check for an MPC 7447A or 7448 CPU */
91 switch (vers) {
92 case MPC7447A:
93 case MPC7448:
94 break;
95 default:
96 return;
97 }
98
99 /* Make sure we're not being doubly invoked. */
100 if (device_find_child(parent, "dfs", -1) != NULL)
101 return;
102
103 /*
104 * We attach a child for every CPU since settings need to
105 * be performed on every CPU in the SMP case.
106 */
107 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL)
108 device_printf(parent, "add dfs child failed\n");
109 }
110
111 static int
dfs_probe(device_t dev)112 dfs_probe(device_t dev)
113 {
114 if (resource_disabled("dfs", 0))
115 return (ENXIO);
116
117 device_set_desc(dev, "Dynamic Frequency Switching");
118 return (0);
119 }
120
121 static int
dfs_attach(device_t dev)122 dfs_attach(device_t dev)
123 {
124 struct dfs_softc *sc;
125 uint16_t vers;
126
127 sc = device_get_softc(dev);
128 sc->dev = dev;
129 sc->dfs4 = 0;
130 vers = mfpvr() >> 16;
131
132 /* The 7448 supports divide-by-four as well */
133 if (vers == MPC7448)
134 sc->dfs4 = 1;
135
136 cpufreq_register(dev);
137 return (0);
138 }
139
140 static int
dfs_settings(device_t dev,struct cf_setting * sets,int * count)141 dfs_settings(device_t dev, struct cf_setting *sets, int *count)
142 {
143 struct dfs_softc *sc;
144 int states;
145
146 sc = device_get_softc(dev);
147 states = sc->dfs4 ? 3 : 2;
148 if (sets == NULL || count == NULL)
149 return (EINVAL);
150 if (*count < states)
151 return (E2BIG);
152
153 /* Return a list of valid settings for this driver. */
154 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states);
155
156 sets[0].freq = 10000; sets[0].dev = dev;
157 sets[1].freq = 5000; sets[1].dev = dev;
158 if (sc->dfs4)
159 sets[2].freq = 2500; sets[2].dev = dev;
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
229