1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2018 Justin Hibbits
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
20 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
22 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/bus.h>
34#include <sys/cpu.h>
35#include <sys/kernel.h>
36#include <sys/module.h>
37
38#include <dev/ofw/openfirm.h>
39
40#include "cpufreq_if.h"
41
42static int pstate_ids[256];
43static int pstate_freqs[256];
44static int npstates;
45
46static void parse_pstates(void)
47{
48	phandle_t node;
49
50	node = OF_finddevice("/ibm,opal/power-mgt");
51
52	/* If this fails, npstates will remain 0, and any attachment will bail. */
53	if (node == -1)
54		return;
55
56	npstates = OF_getencprop(node, "ibm,pstate-ids", pstate_ids,
57	    sizeof(pstate_ids));
58	if (npstates < 0) {
59		npstates = 0;
60		return;
61	}
62
63	if (OF_getencprop(node, "ibm,pstate-frequencies-mhz", pstate_freqs,
64	    sizeof(pstate_freqs)) != npstates) {
65		npstates = 0;
66		return;
67	}
68	npstates /= sizeof(cell_t);
69
70}
71
72/* Make this a sysinit so it runs before the cpufreq driver attaches. */
73SYSINIT(parse_pstates, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, parse_pstates, NULL);
74
75#define	PMCR_UPPERPS_MASK	0xff00000000000000UL
76#define	PMCR_UPPERPS_SHIFT	56
77#define	PMCR_LOWERPS_MASK	0x00ff000000000000UL
78#define	PMCR_LOWERPS_SHIFT	48
79#define	PMCR_VERSION_MASK	0x0000000f
80#define	  PMCR_VERSION_1	  1
81
82struct pmcr_softc {
83	device_t dev;
84};
85
86static void	pmcr_identify(driver_t *driver, device_t parent);
87static int	pmcr_probe(device_t dev);
88static int	pmcr_attach(device_t dev);
89static int	pmcr_settings(device_t dev, struct cf_setting *sets, int *count);
90static int	pmcr_set(device_t dev, const struct cf_setting *set);
91static int	pmcr_get(device_t dev, struct cf_setting *set);
92static int	pmcr_type(device_t dev, int *type);
93
94static device_method_t pmcr_methods[] = {
95	/* Device interface */
96	DEVMETHOD(device_identify,	pmcr_identify),
97	DEVMETHOD(device_probe,		pmcr_probe),
98	DEVMETHOD(device_attach,	pmcr_attach),
99
100	/* cpufreq interface */
101	DEVMETHOD(cpufreq_drv_set,	pmcr_set),
102	DEVMETHOD(cpufreq_drv_get,	pmcr_get),
103	DEVMETHOD(cpufreq_drv_type,	pmcr_type),
104	DEVMETHOD(cpufreq_drv_settings,	pmcr_settings),
105	{0, 0}
106};
107
108static driver_t pmcr_driver = {
109	"pmcr",
110	pmcr_methods,
111	sizeof(struct pmcr_softc)
112};
113
114static devclass_t pmcr_devclass;
115DRIVER_MODULE(pmcr, cpu, pmcr_driver, pmcr_devclass, 0, 0);
116
117static void
118pmcr_identify(driver_t *driver, device_t parent)
119{
120
121	/* Make sure we're not being doubly invoked. */
122	if (device_find_child(parent, "pmcr", -1) != NULL)
123		return;
124
125	/*
126	 * We attach a child for every CPU since settings need to
127	 * be performed on every CPU in the SMP case.
128	 */
129	if (BUS_ADD_CHILD(parent, 10, "pmcr", -1) == NULL)
130		device_printf(parent, "add pmcr child failed\n");
131}
132
133static int
134pmcr_probe(device_t dev)
135{
136	if (resource_disabled("pmcr", 0))
137		return (ENXIO);
138
139	if (npstates == 0)
140		return (ENXIO);
141
142	device_set_desc(dev, "Power Management Control Register");
143	return (0);
144}
145
146static int
147pmcr_attach(device_t dev)
148{
149	struct pmcr_softc *sc;
150
151	sc = device_get_softc(dev);
152	sc->dev = dev;
153
154	cpufreq_register(dev);
155	return (0);
156}
157
158static int
159pmcr_settings(device_t dev, struct cf_setting *sets, int *count)
160{
161	struct pmcr_softc *sc;
162	int i;
163
164	sc = device_get_softc(dev);
165	if (sets == NULL || count == NULL)
166		return (EINVAL);
167	if (*count < npstates)
168		return (E2BIG);
169
170	/* Return a list of valid settings for this driver. */
171	memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * npstates);
172
173	for (i = 0; i < npstates; i++) {
174		sets[i].freq = pstate_freqs[i];
175		sets[i].spec[0] = pstate_ids[i];
176		sets[i].spec[1] = i;
177		sets[i].dev = dev;
178	}
179	*count = npstates;
180
181	return (0);
182}
183
184static int
185pmcr_set(device_t dev, const struct cf_setting *set)
186{
187	register_t pmcr;
188
189	if (set == NULL)
190		return (EINVAL);
191
192	if (set->spec[1] < 0 || set->spec[1] >= npstates)
193		return (EINVAL);
194
195	pmcr = ((long)set->spec[0] << PMCR_LOWERPS_SHIFT) & PMCR_LOWERPS_MASK;
196	pmcr |= ((long)set->spec[0] << PMCR_UPPERPS_SHIFT) & PMCR_UPPERPS_MASK;
197	pmcr |= PMCR_VERSION_1;
198
199	mtspr(SPR_PMCR, pmcr);
200	powerpc_sync(); isync();
201
202	return (0);
203}
204
205static int
206pmcr_get(device_t dev, struct cf_setting *set)
207{
208	struct pmcr_softc *sc;
209	register_t pmcr;
210	int i, pstate;
211
212	if (set == NULL)
213		return (EINVAL);
214	sc = device_get_softc(dev);
215
216	memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
217
218	pmcr = mfspr(SPR_PMCR);
219
220	pstate = (pmcr & PMCR_LOWERPS_MASK) >> PMCR_LOWERPS_SHIFT;
221
222	for (i = 0; i < npstates && pstate_ids[i] != pstate; i++)
223		;
224
225	if (i == npstates)
226		return (EINVAL);
227
228	set->spec[0] = pstate;
229	set->spec[1] = i;
230	set->freq = pstate_freqs[i];
231
232	set->dev = dev;
233
234	return (0);
235}
236
237static int
238pmcr_type(device_t dev, int *type)
239{
240
241	if (type == NULL)
242		return (EINVAL);
243
244	*type = CPUFREQ_TYPE_ABSOLUTE;
245	return (0);
246}
247