2 * Copyright (c) 2000, 2001 Michael Smith
3 * Copyright (c) 2000 BSDi
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
27 * $FreeBSD: src/sys/dev/acpica/acpi_timer.c,v 1.25 2003/08/28 16:06:30 njl Exp $
28 * $DragonFly: src/sys/dev/acpica5/acpi_timer.c,v 1.1 2004/02/21 06:48:08 dillon Exp $
31 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/sysctl.h>
35 #if __FreeBSD_version >= 500000
36 #include <sys/timetc.h>
41 #include <machine/bus.h>
42 #include <machine/resource.h>
44 #include <bus/pci/pcivar.h>
52 * A timecounter based on the free-running ACPI timer.
54 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
57 /* Hooks for the ACPI CA debugging infrastructure */
58 #define _COMPONENT ACPI_SYSTEM
59 ACPI_MODULE_NAME("TIMER")
61 static device_t acpi_timer_dev;
62 struct resource *acpi_timer_reg;
64 static u_int acpi_timer_frequency = 14318182 / 4;
66 static void acpi_timer_identify(driver_t *driver, device_t parent);
67 static int acpi_timer_probe(device_t dev);
68 static int acpi_timer_attach(device_t dev);
69 static unsigned acpi_timer_get_timecount(struct timecounter *tc);
70 static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
71 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
72 static void acpi_timer_test(void);
74 static uint32_t read_counter(void);
75 static int test_counter(void);
77 static device_method_t acpi_timer_methods[] = {
78 DEVMETHOD(device_identify, acpi_timer_identify),
79 DEVMETHOD(device_probe, acpi_timer_probe),
80 DEVMETHOD(device_attach, acpi_timer_attach),
85 static driver_t acpi_timer_driver = {
91 static devclass_t acpi_timer_devclass;
92 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
94 static struct timecounter acpi_timer_timecounter = {
95 acpi_timer_get_timecount_safe,
106 bus_space_handle_t bsh;
110 bsh = rman_get_bushandle(acpi_timer_reg);
111 bst = rman_get_bustag(acpi_timer_reg);
112 tv = bus_space_read_4(bst, bsh, 0);
113 bus_space_barrier(bst, bsh, 0, 4, BUS_SPACE_BARRIER_READ);
123 int min, max, n, delta;
127 last = read_counter();
128 for (n = 0; n < N; n++) {
129 this = read_counter();
130 delta = (this - last) & 0xffffff;
133 else if (delta < min)
139 else if (min < 0 || max == 0)
144 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
146 min, max, max - min);
154 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
158 acpi_timer_identify(driver_t *driver, device_t parent)
163 int i, j, rid, rtype;
165 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
167 if (acpi_disabled("timer") || AcpiGbl_FADT == NULL)
170 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
171 device_printf(parent, "could not add acpi_timer0\n");
174 acpi_timer_dev = dev;
177 rlen = AcpiGbl_FADT->PmTmLen;
178 rtype = (AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId)
179 ? SYS_RES_IOPORT : SYS_RES_MEMORY;
180 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
181 bus_set_resource(dev, rtype, rid, rstart, rlen);
182 acpi_timer_reg = bus_alloc_resource(dev, rtype, &rid, 0, ~0, 1, RF_ACTIVE);
183 if (acpi_timer_reg == NULL) {
184 device_printf(dev, "couldn't allocate I/O resource (%s 0x%lx)\n",
185 rtype == SYS_RES_IOPORT ? "port" : "mem", rstart);
188 if (testenv("debug.acpi.timer_test"))
191 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
193 for(i = 0; i < 10; i++)
196 acpi_timer_timecounter.tc_name = "ACPI-fast";
197 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
199 acpi_timer_timecounter.tc_name = "ACPI-safe";
200 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
202 tc_init(&acpi_timer_timecounter);
204 sprintf(desc, "%d-bit timer at 3.579545MHz",
205 AcpiGbl_FADT->TmrValExt ? 32 : 24);
206 device_set_desc_copy(dev, desc);
212 acpi_timer_probe(device_t dev)
214 if (dev == acpi_timer_dev)
221 acpi_timer_attach(device_t dev)
227 * Fetch current time value from reliable hardware.
230 acpi_timer_get_timecount(struct timecounter *tc)
232 return (read_counter());
236 * Fetch current time value from hardware that may not correctly
240 acpi_timer_get_timecount_safe(struct timecounter *tc)
250 } while (u1 > u2 || u2 > u3 || u3 - u1 > 15);
256 * Timecounter freqency adjustment interface.
259 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
264 if (acpi_timer_timecounter.tc_frequency == 0)
266 freq = acpi_timer_frequency;
267 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
268 if (error == 0 && req->newptr != NULL) {
269 acpi_timer_frequency = freq;
270 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
276 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
277 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
280 * Test harness for verifying ACPI timer behaviour.
281 * Boot with debug.acpi.timer_test set to invoke this.
284 acpi_timer_test(void)
286 u_int32_t u1, u2, u3;
292 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
295 * The failure case is where u3 > u1, but u2 does not fall between
296 * the two, ie. it contains garbage.
299 if (u2 < u1 || u2 > u3)
300 device_printf(acpi_timer_dev,
301 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
311 * Chipset workaround driver hung off PCI.
313 * Some ACPI timers are known or believed to suffer from implementation
314 * problems which can lead to erroneous values being read from the timer.
316 * Since we can't trust unknown chipsets, we default to a timer-read
317 * routine which compensates for the most common problem (as detailed
318 * in the excerpt from the Intel PIIX4 datasheet below).
320 * When we detect a known-functional chipset, we disable the workaround
323 * ] 20. ACPI Timer Errata
325 * ] Problem: The power management timer may return improper result when
326 * ] read. Although the timer value settles properly after incrementing,
327 * ] while incrementing there is a 3nS window every 69.8nS where the
328 * ] timer value is indeterminate (a 4.2% chance that the data will be
329 * ] incorrect when read). As a result, the ACPI free running count up
330 * ] timer specification is violated due to erroneous reads. Implication:
331 * ] System hangs due to the "inaccuracy" of the timer when used by
332 * ] software for time critical events and delays.
334 * ] Workaround: Read the register twice and compare.
335 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
338 * The counter is in other words not latched to the PCI bus clock when
339 * read. Notice the workaround isn't: We need to read until we have
340 * three monotonic samples and then use the middle one, otherwise we are
341 * not protected against the fact that the bits can be wrong in two
342 * directions. If we only cared about monosity two reads would be enough.
346 static int acpi_timer_pci_probe(device_t dev);
348 static device_method_t acpi_timer_pci_methods[] = {
349 DEVMETHOD(device_probe, acpi_timer_pci_probe),
353 static driver_t acpi_timer_pci_driver = {
355 acpi_timer_pci_methods,
359 devclass_t acpi_timer_pci_devclass;
360 DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver,
361 acpi_timer_pci_devclass, 0, 0);
364 * Look at PCI devices going past; if we detect one we know contains
365 * a functional ACPI timer device, enable the faster timecounter read
369 acpi_timer_pci_probe(device_t dev)
371 int vendor, device, revid;
373 vendor = pci_get_vendor(dev);
374 device = pci_get_device(dev);
375 revid = pci_get_revid(dev);
377 /* Detect the PIIX4M and i440MX, respectively */
378 if ((vendor == 0x8086 && device == 0x7113 && revid >= 0x03) ||
379 (vendor == 0x8086 && device == 0x719b)) {
381 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
382 acpi_timer_timecounter.tc_name = "ACPI-fast";
384 device_printf(acpi_timer_dev,"functional ACPI timer detected, "
385 "enabling fast timecount interface\n");
389 /* We never match anything */