2 * Copyright (c) 2003-2005 Nate Lawson (SDG)
3 * Copyright (c) 2001 Michael Smith
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, 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
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
40 #include <machine/bus.h>
42 #include <contrib/dev/acpica/include/acpi.h>
44 #include <dev/acpica/acpivar.h>
45 #include <dev/pci/pcivar.h>
47 #include "cpufreq_if.h"
50 * Throttling provides relative frequency control. It involves modulating
51 * the clock so that the CPU is active for only a fraction of the normal
52 * clock cycle. It does not change voltage and so is less efficient than
53 * other mechanisms. Since it is relative, it can be used in addition to
54 * absolute cpufreq drivers. We support the ACPI 2.0 specification.
57 struct acpi_throttle_softc {
59 ACPI_HANDLE cpu_handle;
60 uint32_t cpu_p_blk; /* ACPI P_BLK location */
61 uint32_t cpu_p_blk_len; /* P_BLK length (must be 6). */
62 struct resource *cpu_p_cnt; /* Throttling control register */
63 int cpu_p_type; /* Resource type for cpu_p_cnt. */
64 uint32_t cpu_thr_state; /* Current throttle setting. */
67 #define THR_GET_REG(reg) \
68 (bus_space_read_4(rman_get_bustag((reg)), \
69 rman_get_bushandle((reg)), 0))
70 #define THR_SET_REG(reg, val) \
71 (bus_space_write_4(rman_get_bustag((reg)), \
72 rman_get_bushandle((reg)), 0, (val)))
75 * Speeds are stored in counts, from 1 to CPU_MAX_SPEED, and
76 * reported to the user in hundredths of a percent.
78 #define CPU_MAX_SPEED (1 << cpu_duty_width)
79 #define CPU_SPEED_PERCENT(x) ((10000 * (x)) / CPU_MAX_SPEED)
80 #define CPU_SPEED_PRINTABLE(x) (CPU_SPEED_PERCENT(x) / 10), \
81 (CPU_SPEED_PERCENT(x) % 10)
82 #define CPU_P_CNT_THT_EN (1<<4)
83 #define CPU_QUIRK_NO_THROTTLE (1<<1) /* Throttling is not usable. */
85 #define PCI_VENDOR_INTEL 0x8086
86 #define PCI_DEVICE_82371AB_3 0x7113 /* PIIX4 chipset for quirks. */
87 #define PCI_REVISION_A_STEP 0
88 #define PCI_REVISION_B_STEP 1
90 static uint32_t cpu_duty_offset; /* Offset in P_CNT of throttle val. */
91 static uint32_t cpu_duty_width; /* Bit width of throttle value. */
92 static int thr_rid; /* Driver-wide resource id. */
93 static int thr_quirks; /* Indicate any hardware bugs. */
95 static void acpi_throttle_identify(driver_t *driver, device_t parent);
96 static int acpi_throttle_probe(device_t dev);
97 static int acpi_throttle_attach(device_t dev);
98 static int acpi_throttle_evaluate(struct acpi_throttle_softc *sc);
99 static int acpi_throttle_quirks(struct acpi_throttle_softc *sc);
100 static int acpi_thr_settings(device_t dev, struct cf_setting *sets,
102 static int acpi_thr_set(device_t dev, const struct cf_setting *set);
103 static int acpi_thr_get(device_t dev, struct cf_setting *set);
104 static int acpi_thr_type(device_t dev, int *type);
106 static device_method_t acpi_throttle_methods[] = {
107 /* Device interface */
108 DEVMETHOD(device_identify, acpi_throttle_identify),
109 DEVMETHOD(device_probe, acpi_throttle_probe),
110 DEVMETHOD(device_attach, acpi_throttle_attach),
112 /* cpufreq interface */
113 DEVMETHOD(cpufreq_drv_set, acpi_thr_set),
114 DEVMETHOD(cpufreq_drv_get, acpi_thr_get),
115 DEVMETHOD(cpufreq_drv_type, acpi_thr_type),
116 DEVMETHOD(cpufreq_drv_settings, acpi_thr_settings),
120 static driver_t acpi_throttle_driver = {
122 acpi_throttle_methods,
123 sizeof(struct acpi_throttle_softc),
126 static devclass_t acpi_throttle_devclass;
127 DRIVER_MODULE(acpi_throttle, cpu, acpi_throttle_driver, acpi_throttle_devclass,
131 acpi_throttle_identify(driver_t *driver, device_t parent)
137 /* Make sure we're not being doubly invoked. */
138 if (device_find_child(parent, "acpi_throttle", -1))
141 /* Check for a valid duty width and parent CPU type. */
142 handle = acpi_get_handle(parent);
145 if (AcpiGbl_FADT.DutyWidth == 0 ||
146 acpi_get_type(parent) != ACPI_TYPE_PROCESSOR)
150 * Add a child if there's a non-NULL P_BLK and correct length, or
151 * if the _PTC method is present.
154 buf.Length = ACPI_ALLOCATE_BUFFER;
155 if (ACPI_FAILURE(AcpiEvaluateObject(handle, NULL, NULL, &buf)))
157 obj = (ACPI_OBJECT *)buf.Pointer;
158 if ((obj->Processor.PblkAddress && obj->Processor.PblkLength >= 4) ||
159 ACPI_SUCCESS(AcpiEvaluateObject(handle, "_PTC", NULL, NULL))) {
160 if (BUS_ADD_CHILD(parent, 0, "acpi_throttle", -1) == NULL)
161 device_printf(parent, "add throttle child failed\n");
167 acpi_throttle_probe(device_t dev)
170 if (resource_disabled("acpi_throttle", 0))
174 * On i386 platforms at least, ACPI throttling is accomplished by
175 * the chipset modulating the STPCLK# pin based on the duty cycle.
176 * Since p4tcc uses the same mechanism (but internal to the CPU),
177 * we disable acpi_throttle when p4tcc is also present.
179 if (device_find_child(device_get_parent(dev), "p4tcc", -1) &&
180 !resource_disabled("p4tcc", 0))
183 device_set_desc(dev, "ACPI CPU Throttling");
188 acpi_throttle_attach(device_t dev)
190 struct acpi_throttle_softc *sc;
191 struct cf_setting set;
197 sc = device_get_softc(dev);
199 sc->cpu_handle = acpi_get_handle(dev);
202 buf.Length = ACPI_ALLOCATE_BUFFER;
203 status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
204 if (ACPI_FAILURE(status)) {
205 device_printf(dev, "attach failed to get Processor obj - %s\n",
206 AcpiFormatException(status));
209 obj = (ACPI_OBJECT *)buf.Pointer;
210 sc->cpu_p_blk = obj->Processor.PblkAddress;
211 sc->cpu_p_blk_len = obj->Processor.PblkLength;
214 /* If this is the first device probed, check for quirks. */
215 if (device_get_unit(dev) == 0)
216 acpi_throttle_quirks(sc);
218 /* Attempt to attach the actual throttling register. */
219 error = acpi_throttle_evaluate(sc);
224 * Set our initial frequency to the highest since some systems
225 * seem to boot with this at the lowest setting.
228 acpi_thr_set(dev, &set);
230 /* Everything went ok, register with cpufreq(4). */
231 cpufreq_register(dev);
236 acpi_throttle_evaluate(struct acpi_throttle_softc *sc)
241 ACPI_GENERIC_ADDRESS gas;
244 /* Get throttling parameters from the FADT. 0 means not supported. */
245 if (device_get_unit(sc->cpu_dev) == 0) {
246 cpu_duty_offset = AcpiGbl_FADT.DutyOffset;
247 cpu_duty_width = AcpiGbl_FADT.DutyWidth;
249 if (cpu_duty_width == 0 || (thr_quirks & CPU_QUIRK_NO_THROTTLE) != 0)
252 /* Validate the duty offset/width. */
253 duty_end = cpu_duty_offset + cpu_duty_width - 1;
255 device_printf(sc->cpu_dev,
256 "CLK_VAL field overflows P_CNT register\n");
259 if (cpu_duty_offset <= 4 && duty_end >= 4) {
260 device_printf(sc->cpu_dev,
261 "CLK_VAL field overlaps THT_EN bit\n");
266 * If not present, fall back to using the processor's P_BLK to find
267 * the P_CNT register.
269 * Note that some systems seem to duplicate the P_BLK pointer
270 * across multiple CPUs, so not getting the resource is not fatal.
273 buf.Length = sizeof(obj);
274 status = AcpiEvaluateObject(sc->cpu_handle, "_PTC", NULL, &buf);
275 if (ACPI_SUCCESS(status)) {
276 if (obj.Buffer.Length < sizeof(ACPI_GENERIC_ADDRESS) + 3) {
277 device_printf(sc->cpu_dev, "_PTC buffer too small\n");
280 memcpy(&gas, obj.Buffer.Pointer + 3, sizeof(gas));
281 acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
282 &gas, &sc->cpu_p_cnt, 0);
283 if (sc->cpu_p_cnt != NULL && bootverbose) {
284 device_printf(sc->cpu_dev, "P_CNT from _PTC %#jx\n",
289 /* If _PTC not present or other failure, try the P_BLK. */
290 if (sc->cpu_p_cnt == NULL) {
292 * The spec says P_BLK must be 6 bytes long. However, some
293 * systems use it to indicate a fractional set of features
294 * present so we take anything >= 4.
296 if (sc->cpu_p_blk_len < 4)
298 gas.Address = sc->cpu_p_blk;
299 gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
301 acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
302 &gas, &sc->cpu_p_cnt, 0);
303 if (sc->cpu_p_cnt != NULL) {
305 device_printf(sc->cpu_dev,
306 "P_CNT from P_BLK %#x\n", sc->cpu_p_blk);
308 device_printf(sc->cpu_dev, "failed to attach P_CNT\n");
318 acpi_throttle_quirks(struct acpi_throttle_softc *sc)
322 /* Look for various quirks of the PIIX4 part. */
323 acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
325 switch (pci_get_revid(acpi_dev)) {
327 * Disable throttling control on PIIX4 A and B-step.
328 * See specification changes #13 ("Manual Throttle Duty Cycle")
329 * and #14 ("Enabling and Disabling Manual Throttle"), plus
330 * erratum #5 ("STPCLK# Deassertion Time") from the January
331 * 2002 PIIX4 specification update. Note that few (if any)
332 * mobile systems ever used this part.
334 case PCI_REVISION_A_STEP:
335 case PCI_REVISION_B_STEP:
336 thr_quirks |= CPU_QUIRK_NO_THROTTLE;
347 acpi_thr_settings(device_t dev, struct cf_setting *sets, int *count)
351 if (sets == NULL || count == NULL)
353 if (*count < CPU_MAX_SPEED)
356 /* Return a list of valid settings for this driver. */
357 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * CPU_MAX_SPEED);
358 for (i = 0, speed = CPU_MAX_SPEED; speed != 0; i++, speed--) {
359 sets[i].freq = CPU_SPEED_PERCENT(speed);
362 *count = CPU_MAX_SPEED;
368 acpi_thr_set(device_t dev, const struct cf_setting *set)
370 struct acpi_throttle_softc *sc;
371 uint32_t clk_val, p_cnt, speed;
375 sc = device_get_softc(dev);
378 * Validate requested state converts to a duty cycle that is an
379 * integer from [1 .. CPU_MAX_SPEED].
381 speed = set->freq * CPU_MAX_SPEED / 10000;
382 if (speed * 10000 != set->freq * CPU_MAX_SPEED ||
383 speed < 1 || speed > CPU_MAX_SPEED)
386 /* If we're at this setting, don't bother applying it again. */
387 if (speed == sc->cpu_thr_state)
390 /* Get the current P_CNT value and disable throttling */
391 p_cnt = THR_GET_REG(sc->cpu_p_cnt);
392 p_cnt &= ~CPU_P_CNT_THT_EN;
393 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
395 /* If we're at maximum speed, that's all */
396 if (speed < CPU_MAX_SPEED) {
397 /* Mask the old CLK_VAL off and OR in the new value */
398 clk_val = (CPU_MAX_SPEED - 1) << cpu_duty_offset;
400 p_cnt |= (speed << cpu_duty_offset);
402 /* Write the new P_CNT value and then enable throttling */
403 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
404 p_cnt |= CPU_P_CNT_THT_EN;
405 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
407 sc->cpu_thr_state = speed;
413 acpi_thr_get(device_t dev, struct cf_setting *set)
415 struct acpi_throttle_softc *sc;
416 uint32_t p_cnt, clk_val;
420 sc = device_get_softc(dev);
422 /* Get the current throttling setting from P_CNT. */
423 p_cnt = THR_GET_REG(sc->cpu_p_cnt);
424 clk_val = (p_cnt >> cpu_duty_offset) & (CPU_MAX_SPEED - 1);
425 sc->cpu_thr_state = clk_val;
427 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
428 set->freq = CPU_SPEED_PERCENT(clk_val);
435 acpi_thr_type(device_t dev, int *type)
441 *type = CPUFREQ_TYPE_RELATIVE;