1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
29#include <sys/systm.h>
30#include <sys/bus.h>
31#include <sys/cpu.h>
32#include <sys/kernel.h>
33#include <sys/module.h>
34
35#include <dev/ofw/openfirm.h>
36
37#include "cpufreq_if.h"
38
39static int pstate_ids[256];
40static int pstate_freqs[256];
41static int npstates;
42
43static void parse_pstates(void)
44{
45	phandle_t node;
46
47	node = OF_finddevice("/ibm,opal/power-mgt");
48
49	/* If this fails, npstates will remain 0, and any attachment will bail. */
50	if (node == -1)
51		return;
52
53	npstates = OF_getencprop(node, "ibm,pstate-ids", pstate_ids,
54	    sizeof(pstate_ids));
55	if (npstates < 0) {
56		npstates = 0;
57		return;
58	}
59
60	if (OF_getencprop(node, "ibm,pstate-frequencies-mhz", pstate_freqs,
61	    sizeof(pstate_freqs)) != npstates) {
62		npstates = 0;
63		return;
64	}
65	npstates /= sizeof(cell_t);
66
67}
68
69/* Make this a sysinit so it runs before the cpufreq driver attaches. */
70SYSINIT(parse_pstates, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, parse_pstates, NULL);
71
72#define	PMCR_UPPERPS_MASK	0xff00000000000000UL
73#define	PMCR_UPPERPS_SHIFT	56
74#define	PMCR_LOWERPS_MASK	0x00ff000000000000UL
75#define	PMCR_LOWERPS_SHIFT	48
76#define	PMCR_VERSION_MASK	0x0000000f
77#define	  PMCR_VERSION_1	  1
78
79struct pmcr_softc {
80	device_t dev;
81};
82
83static void	pmcr_identify(driver_t *driver, device_t parent);
84static int	pmcr_probe(device_t dev);
85static int	pmcr_attach(device_t dev);
86static int	pmcr_settings(device_t dev, struct cf_setting *sets, int *count);
87static int	pmcr_set(device_t dev, const struct cf_setting *set);
88static int	pmcr_get(device_t dev, struct cf_setting *set);
89static int	pmcr_type(device_t dev, int *type);
90
91static device_method_t pmcr_methods[] = {
92	/* Device interface */
93	DEVMETHOD(device_identify,	pmcr_identify),
94	DEVMETHOD(device_probe,		pmcr_probe),
95	DEVMETHOD(device_attach,	pmcr_attach),
96
97	/* cpufreq interface */
98	DEVMETHOD(cpufreq_drv_set,	pmcr_set),
99	DEVMETHOD(cpufreq_drv_get,	pmcr_get),
100	DEVMETHOD(cpufreq_drv_type,	pmcr_type),
101	DEVMETHOD(cpufreq_drv_settings,	pmcr_settings),
102	{0, 0}
103};
104
105static driver_t pmcr_driver = {
106	"pmcr",
107	pmcr_methods,
108	sizeof(struct pmcr_softc)
109};
110
111DRIVER_MODULE(pmcr, cpu, pmcr_driver, 0, 0);
112
113static void
114pmcr_identify(driver_t *driver, device_t parent)
115{
116
117	/* Make sure we're not being doubly invoked. */
118	if (device_find_child(parent, "pmcr", -1) != NULL)
119		return;
120
121	/*
122	 * We attach a child for every CPU since settings need to
123	 * be performed on every CPU in the SMP case.
124	 */
125	if (BUS_ADD_CHILD(parent, 10, "pmcr", -1) == NULL)
126		device_printf(parent, "add pmcr child failed\n");
127}
128
129static int
130pmcr_probe(device_t dev)
131{
132	if (resource_disabled("pmcr", 0))
133		return (ENXIO);
134
135	if (npstates == 0)
136		return (ENXIO);
137
138	device_set_desc(dev, "Power Management Control Register");
139	return (0);
140}
141
142static int
143pmcr_attach(device_t dev)
144{
145	struct pmcr_softc *sc;
146
147	sc = device_get_softc(dev);
148	sc->dev = dev;
149
150	cpufreq_register(dev);
151	return (0);
152}
153
154static int
155pmcr_settings(device_t dev, struct cf_setting *sets, int *count)
156{
157	int i;
158
159	if (sets == NULL || count == NULL)
160		return (EINVAL);
161	if (*count < npstates)
162		return (E2BIG);
163
164	/* Return a list of valid settings for this driver. */
165	memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * npstates);
166
167	for (i = 0; i < npstates; i++) {
168		sets[i].freq = pstate_freqs[i];
169		sets[i].spec[0] = pstate_ids[i];
170		sets[i].spec[1] = i;
171		sets[i].dev = dev;
172	}
173	*count = npstates;
174
175	return (0);
176}
177
178static int
179pmcr_set(device_t dev, const struct cf_setting *set)
180{
181	register_t pmcr;
182
183	if (set == NULL)
184		return (EINVAL);
185
186	if (set->spec[1] < 0 || set->spec[1] >= npstates)
187		return (EINVAL);
188
189	pmcr = ((long)set->spec[0] << PMCR_LOWERPS_SHIFT) & PMCR_LOWERPS_MASK;
190	pmcr |= ((long)set->spec[0] << PMCR_UPPERPS_SHIFT) & PMCR_UPPERPS_MASK;
191	pmcr |= PMCR_VERSION_1;
192
193	mtspr(SPR_PMCR, pmcr);
194	powerpc_sync(); isync();
195
196	return (0);
197}
198
199static int
200pmcr_get(device_t dev, struct cf_setting *set)
201{
202	register_t pmcr;
203	int i, pstate;
204
205	if (set == NULL)
206		return (EINVAL);
207
208	memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
209
210	pmcr = mfspr(SPR_PMCR);
211
212	pstate = (pmcr & PMCR_LOWERPS_MASK) >> PMCR_LOWERPS_SHIFT;
213
214	for (i = 0; i < npstates && pstate_ids[i] != pstate; i++)
215		;
216
217	if (i == npstates)
218		return (EINVAL);
219
220	set->spec[0] = pstate;
221	set->spec[1] = i;
222	set->freq = pstate_freqs[i];
223
224	set->dev = dev;
225
226	return (0);
227}
228
229static int
230pmcr_type(device_t dev, int *type)
231{
232
233	if (type == NULL)
234		return (EINVAL);
235
236	*type = CPUFREQ_TYPE_ABSOLUTE;
237	return (0);
238}
239