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>
30 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/module.h>
38 #include <machine/bus.h>
40 #include <contrib/dev/acpica/include/acpi.h>
42 #include <dev/acpica/acpivar.h>
43 #include <dev/pci/pcivar.h>
45 #include "cpufreq_if.h"
48 * Throttling provides relative frequency control. It involves modulating
49 * the clock so that the CPU is active for only a fraction of the normal
50 * clock cycle. It does not change voltage and so is less efficient than
51 * other mechanisms. Since it is relative, it can be used in addition to
52 * absolute cpufreq drivers. We support the ACPI 2.0 specification.
55 struct acpi_throttle_softc {
57 ACPI_HANDLE cpu_handle;
58 uint32_t cpu_p_blk; /* ACPI P_BLK location */
59 uint32_t cpu_p_blk_len; /* P_BLK length (must be 6). */
60 struct resource *cpu_p_cnt; /* Throttling control register */
61 int cpu_p_type; /* Resource type for cpu_p_cnt. */
62 uint32_t cpu_thr_state; /* Current throttle setting. */
65 #define THR_GET_REG(reg) \
66 (bus_space_read_4(rman_get_bustag((reg)), \
67 rman_get_bushandle((reg)), 0))
68 #define THR_SET_REG(reg, val) \
69 (bus_space_write_4(rman_get_bustag((reg)), \
70 rman_get_bushandle((reg)), 0, (val)))
73 * Speeds are stored in counts, from 1 to CPU_MAX_SPEED, and
74 * reported to the user in hundredths of a percent.
76 #define CPU_MAX_SPEED (1 << cpu_duty_width)
77 #define CPU_SPEED_PERCENT(x) ((10000 * (x)) / CPU_MAX_SPEED)
78 #define CPU_SPEED_PRINTABLE(x) (CPU_SPEED_PERCENT(x) / 10), \
79 (CPU_SPEED_PERCENT(x) % 10)
80 #define CPU_P_CNT_THT_EN (1<<4)
81 #define CPU_QUIRK_NO_THROTTLE (1<<1) /* Throttling is not usable. */
83 #define PCI_VENDOR_INTEL 0x8086
84 #define PCI_DEVICE_82371AB_3 0x7113 /* PIIX4 chipset for quirks. */
85 #define PCI_REVISION_A_STEP 0
86 #define PCI_REVISION_B_STEP 1
88 static uint32_t cpu_duty_offset; /* Offset in P_CNT of throttle val. */
89 static uint32_t cpu_duty_width; /* Bit width of throttle value. */
90 static int thr_rid; /* Driver-wide resource id. */
91 static int thr_quirks; /* Indicate any hardware bugs. */
93 static void acpi_throttle_identify(driver_t *driver, device_t parent);
94 static int acpi_throttle_probe(device_t dev);
95 static int acpi_throttle_attach(device_t dev);
96 static int acpi_throttle_evaluate(struct acpi_throttle_softc *sc);
97 static void acpi_throttle_quirks(struct acpi_throttle_softc *sc);
98 static int acpi_thr_settings(device_t dev, struct cf_setting *sets,
100 static int acpi_thr_set(device_t dev, const struct cf_setting *set);
101 static int acpi_thr_get(device_t dev, struct cf_setting *set);
102 static int acpi_thr_type(device_t dev, int *type);
104 static device_method_t acpi_throttle_methods[] = {
105 /* Device interface */
106 DEVMETHOD(device_identify, acpi_throttle_identify),
107 DEVMETHOD(device_probe, acpi_throttle_probe),
108 DEVMETHOD(device_attach, acpi_throttle_attach),
110 /* cpufreq interface */
111 DEVMETHOD(cpufreq_drv_set, acpi_thr_set),
112 DEVMETHOD(cpufreq_drv_get, acpi_thr_get),
113 DEVMETHOD(cpufreq_drv_type, acpi_thr_type),
114 DEVMETHOD(cpufreq_drv_settings, acpi_thr_settings),
118 static driver_t acpi_throttle_driver = {
120 acpi_throttle_methods,
121 sizeof(struct acpi_throttle_softc),
124 DRIVER_MODULE(acpi_throttle, cpu, acpi_throttle_driver, 0, 0);
127 acpi_throttle_identify(driver_t *driver, device_t parent)
133 /* Make sure we're not being doubly invoked. */
134 if (device_find_child(parent, "acpi_throttle", -1))
137 /* Check for a valid duty width and parent CPU type. */
138 handle = acpi_get_handle(parent);
141 if (AcpiGbl_FADT.DutyWidth == 0 ||
142 acpi_get_type(parent) != ACPI_TYPE_PROCESSOR)
146 * Add a child if there's a non-NULL P_BLK and correct length, or
147 * if the _PTC method is present.
150 buf.Length = ACPI_ALLOCATE_BUFFER;
151 if (ACPI_FAILURE(AcpiEvaluateObject(handle, NULL, NULL, &buf)))
153 obj = (ACPI_OBJECT *)buf.Pointer;
154 if ((obj->Processor.PblkAddress && obj->Processor.PblkLength >= 4) ||
155 ACPI_SUCCESS(AcpiEvaluateObject(handle, "_PTC", NULL, NULL))) {
156 if (BUS_ADD_CHILD(parent, 0, "acpi_throttle",
157 device_get_unit(parent)) == NULL)
158 device_printf(parent, "add throttle child failed\n");
164 acpi_throttle_probe(device_t dev)
167 if (resource_disabled("acpi_throttle", 0))
171 * On i386 platforms at least, ACPI throttling is accomplished by
172 * the chipset modulating the STPCLK# pin based on the duty cycle.
173 * Since p4tcc uses the same mechanism (but internal to the CPU),
174 * we disable acpi_throttle when p4tcc is also present.
176 if (device_find_child(device_get_parent(dev), "p4tcc", -1) &&
177 !resource_disabled("p4tcc", 0))
180 device_set_desc(dev, "ACPI CPU Throttling");
185 acpi_throttle_attach(device_t dev)
187 struct acpi_throttle_softc *sc;
188 struct cf_setting set;
194 sc = device_get_softc(dev);
196 sc->cpu_handle = acpi_get_handle(dev);
199 buf.Length = ACPI_ALLOCATE_BUFFER;
200 status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
201 if (ACPI_FAILURE(status)) {
202 device_printf(dev, "attach failed to get Processor obj - %s\n",
203 AcpiFormatException(status));
206 obj = (ACPI_OBJECT *)buf.Pointer;
207 sc->cpu_p_blk = obj->Processor.PblkAddress;
208 sc->cpu_p_blk_len = obj->Processor.PblkLength;
211 /* If this is the first device probed, check for quirks. */
212 if (device_get_unit(dev) == 0)
213 acpi_throttle_quirks(sc);
215 /* Attempt to attach the actual throttling register. */
216 error = acpi_throttle_evaluate(sc);
221 * Set our initial frequency to the highest since some systems
222 * seem to boot with this at the lowest setting.
225 acpi_thr_set(dev, &set);
227 /* Everything went ok, register with cpufreq(4). */
228 cpufreq_register(dev);
233 acpi_throttle_evaluate(struct acpi_throttle_softc *sc)
238 ACPI_GENERIC_ADDRESS gas;
241 /* Get throttling parameters from the FADT. 0 means not supported. */
242 if (device_get_unit(sc->cpu_dev) == 0) {
243 cpu_duty_offset = AcpiGbl_FADT.DutyOffset;
244 cpu_duty_width = AcpiGbl_FADT.DutyWidth;
246 if (cpu_duty_width == 0 || (thr_quirks & CPU_QUIRK_NO_THROTTLE) != 0)
249 /* Validate the duty offset/width. */
250 duty_end = cpu_duty_offset + cpu_duty_width - 1;
252 device_printf(sc->cpu_dev,
253 "CLK_VAL field overflows P_CNT register\n");
256 if (cpu_duty_offset <= 4 && duty_end >= 4) {
257 device_printf(sc->cpu_dev,
258 "CLK_VAL field overlaps THT_EN bit\n");
263 * If not present, fall back to using the processor's P_BLK to find
264 * the P_CNT register.
266 * Note that some systems seem to duplicate the P_BLK pointer
267 * across multiple CPUs, so not getting the resource is not fatal.
270 buf.Length = sizeof(obj);
271 status = AcpiEvaluateObject(sc->cpu_handle, "_PTC", NULL, &buf);
272 if (ACPI_SUCCESS(status)) {
273 if (obj.Buffer.Length < sizeof(ACPI_GENERIC_ADDRESS) + 3) {
274 device_printf(sc->cpu_dev, "_PTC buffer too small\n");
277 memcpy(&gas, obj.Buffer.Pointer + 3, sizeof(gas));
278 acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
279 &gas, &sc->cpu_p_cnt, 0);
280 if (sc->cpu_p_cnt != NULL && bootverbose) {
281 device_printf(sc->cpu_dev, "P_CNT from _PTC %#jx\n",
286 /* If _PTC not present or other failure, try the P_BLK. */
287 if (sc->cpu_p_cnt == NULL) {
289 * The spec says P_BLK must be 6 bytes long. However, some
290 * systems use it to indicate a fractional set of features
291 * present so we take anything >= 4.
293 if (sc->cpu_p_blk_len < 4)
295 gas.Address = sc->cpu_p_blk;
296 gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
298 acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
299 &gas, &sc->cpu_p_cnt, 0);
300 if (sc->cpu_p_cnt != NULL) {
302 device_printf(sc->cpu_dev,
303 "P_CNT from P_BLK %#x\n", sc->cpu_p_blk);
305 device_printf(sc->cpu_dev, "failed to attach P_CNT\n");
315 acpi_throttle_quirks(struct acpi_throttle_softc *sc)
320 /* Look for various quirks of the PIIX4 part. */
321 acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
323 switch (pci_get_revid(acpi_dev)) {
325 * Disable throttling control on PIIX4 A and B-step.
326 * See specification changes #13 ("Manual Throttle Duty Cycle")
327 * and #14 ("Enabling and Disabling Manual Throttle"), plus
328 * erratum #5 ("STPCLK# Deassertion Time") from the January
329 * 2002 PIIX4 specification update. Note that few (if any)
330 * mobile systems ever used this part.
332 case PCI_REVISION_A_STEP:
333 case PCI_REVISION_B_STEP:
334 thr_quirks |= CPU_QUIRK_NO_THROTTLE;
344 acpi_thr_settings(device_t dev, struct cf_setting *sets, int *count)
348 if (sets == NULL || count == NULL)
350 if (*count < CPU_MAX_SPEED)
353 /* Return a list of valid settings for this driver. */
354 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * CPU_MAX_SPEED);
355 for (i = 0, speed = CPU_MAX_SPEED; speed != 0; i++, speed--) {
356 sets[i].freq = CPU_SPEED_PERCENT(speed);
359 *count = CPU_MAX_SPEED;
365 acpi_thr_set(device_t dev, const struct cf_setting *set)
367 struct acpi_throttle_softc *sc;
368 uint32_t clk_val, p_cnt, speed;
372 sc = device_get_softc(dev);
375 * Validate requested state converts to a duty cycle that is an
376 * integer from [1 .. CPU_MAX_SPEED].
378 speed = set->freq * CPU_MAX_SPEED / 10000;
379 if (speed * 10000 != set->freq * CPU_MAX_SPEED ||
380 speed < 1 || speed > CPU_MAX_SPEED)
383 /* If we're at this setting, don't bother applying it again. */
384 if (speed == sc->cpu_thr_state)
387 /* Get the current P_CNT value and disable throttling */
388 p_cnt = THR_GET_REG(sc->cpu_p_cnt);
389 p_cnt &= ~CPU_P_CNT_THT_EN;
390 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
392 /* If we're at maximum speed, that's all */
393 if (speed < CPU_MAX_SPEED) {
394 /* Mask the old CLK_VAL off and OR in the new value */
395 clk_val = (CPU_MAX_SPEED - 1) << cpu_duty_offset;
397 p_cnt |= (speed << cpu_duty_offset);
399 /* Write the new P_CNT value and then enable throttling */
400 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
401 p_cnt |= CPU_P_CNT_THT_EN;
402 THR_SET_REG(sc->cpu_p_cnt, p_cnt);
404 sc->cpu_thr_state = speed;
410 acpi_thr_get(device_t dev, struct cf_setting *set)
412 struct acpi_throttle_softc *sc;
413 uint32_t p_cnt, clk_val;
417 sc = device_get_softc(dev);
419 /* Get the current throttling setting from P_CNT. */
420 p_cnt = THR_GET_REG(sc->cpu_p_cnt);
421 clk_val = (p_cnt >> cpu_duty_offset) & (CPU_MAX_SPEED - 1);
422 sc->cpu_thr_state = clk_val;
424 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
425 set->freq = CPU_SPEED_PERCENT(clk_val);
432 acpi_thr_type(device_t dev, int *type)
438 *type = CPUFREQ_TYPE_RELATIVE;