2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 2009 Nathan Whitehorn
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/module.h>
37 #include <dev/ofw/ofw_bus.h>
39 #include "cpufreq_if.h"
47 static void pcr_identify(driver_t *driver, device_t parent);
48 static int pcr_probe(device_t dev);
49 static int pcr_attach(device_t dev);
50 static int pcr_settings(device_t dev, struct cf_setting *sets, int *count);
51 static int pcr_set(device_t dev, const struct cf_setting *set);
52 static int pcr_get(device_t dev, struct cf_setting *set);
53 static int pcr_type(device_t dev, int *type);
55 static device_method_t pcr_methods[] = {
56 /* Device interface */
57 DEVMETHOD(device_identify, pcr_identify),
58 DEVMETHOD(device_probe, pcr_probe),
59 DEVMETHOD(device_attach, pcr_attach),
61 /* cpufreq interface */
62 DEVMETHOD(cpufreq_drv_set, pcr_set),
63 DEVMETHOD(cpufreq_drv_get, pcr_get),
64 DEVMETHOD(cpufreq_drv_type, pcr_type),
65 DEVMETHOD(cpufreq_drv_settings, pcr_settings),
69 static driver_t pcr_driver = {
72 sizeof(struct pcr_softc)
75 DRIVER_MODULE(pcr, cpu, pcr_driver, 0, 0);
81 #define PCR_TO_FREQ(a) ((a >> 17) & 3)
85 #define PCR_QUARTER 2 /* Only on 970MP */
87 #define PSR_RECEIVED (1ULL << 61)
88 #define PSR_COMPLETED (1ULL << 61)
94 #define SCOM_PCR 0x0aa00100 /* Power Control Register */
95 #define SCOM_PCR_BIT 0x80000000 /* Data bit for PCR */
96 #define SCOM_PSR 0x40800100 /* Power Status Register */
102 #define SCOMC_READ 0x00008000
103 #define SCOMC_WRITE 0x00000000
106 write_scom(register_t address, uint64_t value)
109 #ifndef __powerpc64__
110 register_t hi, lo, scratch;
114 mtmsr(msr & ~PSL_EE); isync();
117 mtspr(SPR_SCOMD, value);
119 hi = (value >> 32) & 0xffffffff;
120 lo = value & 0xffffffff;
121 mtspr64(SPR_SCOMD, hi, lo, scratch);
124 mtspr(SPR_SCOMC, address | SCOMC_WRITE);
131 read_scom(register_t address)
137 mtmsr(msr & ~PSL_EE); isync();
139 mtspr(SPR_SCOMC, address | SCOMC_READ);
142 __asm __volatile ("mfspr %0,%1;"
143 " mr %0+1, %0; srdi %0,%0,32" : "=r" (ret) : "K" (SPR_SCOMD));
145 (void)mfspr(SPR_SCOMC); /* Complete transcation */
153 pcr_identify(driver_t *driver, device_t parent)
156 vers = mfpvr() >> 16;
158 /* Check for an IBM 970-class CPU */
168 /* Make sure we're not being doubly invoked. */
169 if (device_find_child(parent, "pcr", -1) != NULL)
173 * We attach a child for every CPU since settings need to
174 * be performed on every CPU in the SMP case.
176 if (BUS_ADD_CHILD(parent, 10, "pcr", -1) == NULL)
177 device_printf(parent, "add pcr child failed\n");
181 pcr_probe(device_t dev)
183 if (resource_disabled("pcr", 0))
186 device_set_desc(dev, "PPC 970 Power Control Register");
191 pcr_attach(device_t dev)
193 struct pcr_softc *sc;
198 sc = device_get_softc(dev);
201 cpu = ofw_bus_get_node(device_get_parent(dev));
204 device_printf(dev,"No CPU device tree node!\n");
208 if (OF_getproplen(cpu, "power-mode-data") <= 0) {
209 /* Use the first CPU's node */
210 cpu = OF_child(OF_parent(cpu));
214 * Collect the PCR values for each mode from the device tree.
215 * These include bus timing information, and so cannot be
218 sc->nmodes = OF_getproplen(cpu, "power-mode-data");
219 if (sc->nmodes <= 0 || sc->nmodes > sizeof(sc->pcr_vals)) {
220 device_printf(dev,"No power mode data in device tree!\n");
223 OF_getprop(cpu, "power-mode-data", modes, sc->nmodes);
224 sc->nmodes /= sizeof(modes[0]);
227 for (i = 0; i < sc->nmodes; i++)
228 sc->pcr_vals[PCR_TO_FREQ(modes[i])] = modes[i];
230 cpufreq_register(dev);
235 pcr_settings(device_t dev, struct cf_setting *sets, int *count)
237 struct pcr_softc *sc;
239 sc = device_get_softc(dev);
240 if (sets == NULL || count == NULL)
242 if (*count < sc->nmodes)
245 /* Return a list of valid settings for this driver. */
246 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * sc->nmodes);
248 sets[0].freq = 10000; sets[0].dev = dev;
249 sets[1].freq = 5000; sets[1].dev = dev;
250 if (sc->nmodes > 2) {
260 pcr_set(device_t dev, const struct cf_setting *set)
262 struct pcr_softc *sc;
268 sc = device_get_softc(dev);
270 /* Construct the new PCR */
274 if (set->freq == 10000)
275 pcr |= sc->pcr_vals[0];
276 else if (set->freq == 5000)
277 pcr |= sc->pcr_vals[1];
278 else if (set->freq == 2500)
279 pcr |= sc->pcr_vals[2];
282 mtmsr(msr & ~PSL_EE); isync();
284 /* 970MP requires PCR and PCRH to be cleared first */
286 write_scom(SCOM_PCR,0); /* Clear PCRH */
287 write_scom(SCOM_PCR,SCOM_PCR_BIT); /* Clear PCR */
291 write_scom(SCOM_PCR, pcr);
293 /* Wait for completion */
297 psr = read_scom(SCOM_PSR);
298 } while ((psr & PSR_RECEIVED) && !(psr & PSR_COMPLETED));
306 pcr_get(device_t dev, struct cf_setting *set)
313 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
315 psr = read_scom(SCOM_PSR);
317 /* We want bits 6 and 7 */
318 psr = (psr >> 56) & 3;
323 else if (psr == PCR_QUARTER)
332 pcr_type(device_t dev, int *type)
338 *type = CPUFREQ_TYPE_RELATIVE;