2 * Copyright (c) 2005 Nate Lawson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
28 * Throttle clock frequency by using the thermal control circuit. This
29 * operates independently of SpeedStep and ACPI throttling and is supported
30 * on Pentium 4 and later models (feature TM).
32 * Reference: Intel Developer's manual v.3 #245472-012
34 * The original version of this driver was written by Ted Unangst for
35 * OpenBSD and imported by Maxim Sobolev. It was rewritten by Nate Lawson
36 * for use with the cpufreq framework.
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
43 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/module.h>
49 #include <machine/md_var.h>
50 #include <machine/specialreg.h>
52 #include "cpufreq_if.h"
54 #include <contrib/dev/acpica/include/acpi.h>
56 #include <dev/acpica/acpivar.h>
66 #define TCC_NUM_SETTINGS 8
68 #define TCC_ENABLE_ONDEMAND (1<<4)
69 #define TCC_REG_OFFSET 1
70 #define TCC_SPEED_PERCENT(x) ((10000 * (x)) / TCC_NUM_SETTINGS)
72 static int p4tcc_features(driver_t *driver, u_int *features);
73 static void p4tcc_identify(driver_t *driver, device_t parent);
74 static int p4tcc_probe(device_t dev);
75 static int p4tcc_attach(device_t dev);
76 static int p4tcc_settings(device_t dev, struct cf_setting *sets,
78 static int p4tcc_set(device_t dev, const struct cf_setting *set);
79 static int p4tcc_get(device_t dev, struct cf_setting *set);
80 static int p4tcc_type(device_t dev, int *type);
82 static device_method_t p4tcc_methods[] = {
83 /* Device interface */
84 DEVMETHOD(device_identify, p4tcc_identify),
85 DEVMETHOD(device_probe, p4tcc_probe),
86 DEVMETHOD(device_attach, p4tcc_attach),
88 /* cpufreq interface */
89 DEVMETHOD(cpufreq_drv_set, p4tcc_set),
90 DEVMETHOD(cpufreq_drv_get, p4tcc_get),
91 DEVMETHOD(cpufreq_drv_type, p4tcc_type),
92 DEVMETHOD(cpufreq_drv_settings, p4tcc_settings),
95 DEVMETHOD(acpi_get_features, p4tcc_features),
100 static driver_t p4tcc_driver = {
103 sizeof(struct p4tcc_softc),
106 static devclass_t p4tcc_devclass;
107 DRIVER_MODULE(p4tcc, cpu, p4tcc_driver, p4tcc_devclass, 0, 0);
110 p4tcc_features(driver_t *driver, u_int *features)
113 /* Notify the ACPI CPU that we support direct access to MSRs */
114 *features = ACPI_CAP_THR_MSRS;
119 p4tcc_identify(driver_t *driver, device_t parent)
122 if ((cpu_feature & (CPUID_ACPI | CPUID_TM)) != (CPUID_ACPI | CPUID_TM))
125 /* Make sure we're not being doubly invoked. */
126 if (device_find_child(parent, "p4tcc", -1) != NULL)
130 * We attach a p4tcc child for every CPU since settings need to
131 * be performed on every CPU in the SMP case. See section 13.15.3
132 * of the IA32 Intel Architecture Software Developer's Manual,
133 * Volume 3, for more info.
135 if (BUS_ADD_CHILD(parent, 10, "p4tcc", -1) == NULL)
136 device_printf(parent, "add p4tcc child failed\n");
140 p4tcc_probe(device_t dev)
143 if (resource_disabled("p4tcc", 0))
146 device_set_desc(dev, "CPU Frequency Thermal Control");
151 p4tcc_attach(device_t dev)
153 struct p4tcc_softc *sc;
154 struct cf_setting set;
156 sc = device_get_softc(dev);
158 sc->set_count = TCC_NUM_SETTINGS;
161 * On boot, the TCC is usually in Automatic mode where reading the
162 * current performance level is likely to produce bogus results.
163 * We record that state here and don't trust the contents of the
164 * status MSR until we've set it ourselves.
166 sc->auto_mode = TRUE;
169 * XXX: After a cursory glance at various Intel specification
170 * XXX: updates it seems like these tests for errata is bogus.
171 * XXX: As far as I can tell, the failure mode is benign, in
172 * XXX: that cpus with no errata will have their bottom two
173 * XXX: STPCLK# rates disabled, so rather than waste more time
174 * XXX: hunting down intel docs, just document it and punt. /phk
176 switch (cpu_id & 0xff) {
183 * These CPU models hang when set to 12.5%.
184 * See Errata O50, P44, and Z21.
188 case 0x07: /* errata N44 and P18 */
192 case 0x62: /* Pentium D B1: errata AA21 */
193 case 0x64: /* Pentium D C1: errata AA21 */
194 case 0x65: /* Pentium D D0: errata AA21 */
196 * These CPU models hang when set to 12.5% or 25%.
197 * See Errata N44, P18l and AA21.
202 sc->lowest_val = TCC_NUM_SETTINGS - sc->set_count + 1;
205 * Before we finish attach, switch to 100%. It's possible the BIOS
206 * set us to a lower rate. The user can override this after boot.
209 p4tcc_set(dev, &set);
211 cpufreq_register(dev);
216 p4tcc_settings(device_t dev, struct cf_setting *sets, int *count)
218 struct p4tcc_softc *sc;
221 sc = device_get_softc(dev);
222 if (sets == NULL || count == NULL)
224 if (*count < sc->set_count)
227 /* Return a list of valid settings for this driver. */
228 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * sc->set_count);
229 val = TCC_NUM_SETTINGS;
230 for (i = 0; i < sc->set_count; i++, val--) {
231 sets[i].freq = TCC_SPEED_PERCENT(val);
234 *count = sc->set_count;
240 p4tcc_set(device_t dev, const struct cf_setting *set)
242 struct p4tcc_softc *sc;
248 sc = device_get_softc(dev);
251 * Validate requested state converts to a setting that is an integer
252 * from [sc->lowest_val .. TCC_NUM_SETTINGS].
254 val = set->freq * TCC_NUM_SETTINGS / 10000;
255 if (val * 10000 != set->freq * TCC_NUM_SETTINGS ||
256 val < sc->lowest_val || val > TCC_NUM_SETTINGS)
260 * Read the current register and mask off the old setting and
261 * On-Demand bit. If the new val is < 100%, set it and the On-Demand
262 * bit, otherwise just return to Automatic mode.
264 msr = rdmsr(MSR_THERM_CONTROL);
265 mask = (TCC_NUM_SETTINGS - 1) << TCC_REG_OFFSET;
266 msr &= ~(mask | TCC_ENABLE_ONDEMAND);
267 if (val < TCC_NUM_SETTINGS)
268 msr |= (val << TCC_REG_OFFSET) | TCC_ENABLE_ONDEMAND;
269 wrmsr(MSR_THERM_CONTROL, msr);
272 * Record whether we're now in Automatic or On-Demand mode. We have
273 * to cache this since there is no reliable way to check if TCC is in
274 * Automatic mode (i.e., at 100% or possibly 50%). Reading bit 4 of
275 * the ACPI Thermal Monitor Control Register produces 0 no matter
276 * what the current mode.
278 if (msr & TCC_ENABLE_ONDEMAND)
279 sc->auto_mode = TRUE;
281 sc->auto_mode = FALSE;
287 p4tcc_get(device_t dev, struct cf_setting *set)
289 struct p4tcc_softc *sc;
295 sc = device_get_softc(dev);
298 * Read the current register and extract the current setting. If
299 * in automatic mode, assume we're at TCC_NUM_SETTINGS (100%).
301 * XXX This is not completely reliable since at high temperatures
302 * the CPU may be automatically throttling to 50% but it's the best
305 if (!sc->auto_mode) {
306 msr = rdmsr(MSR_THERM_CONTROL);
307 val = (msr >> TCC_REG_OFFSET) & (TCC_NUM_SETTINGS - 1);
309 val = TCC_NUM_SETTINGS;
311 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
312 set->freq = TCC_SPEED_PERCENT(val);
319 p4tcc_type(device_t dev, int *type)
325 *type = CPUFREQ_TYPE_RELATIVE;