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 1.24.2.1 2003/08/22 20:49:20 jhb Exp $
28 * $DragonFly: src/sys/dev/acpica/Attic/acpi_timer.c,v 1.3 2004/02/13 00:25:17 joerg Exp $
31 #ifdef NOTDEF /* Disabled */
34 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/sysctl.h>
38 #if defined(__FreeBSD__) && __FreeBSD_version >= 500000
39 #include <sys/timetc.h>
44 #include <machine/bus.h>
45 #include <machine/resource.h>
50 #include <dev/acpica/acpivar.h>
51 #include <bus/pci/pcivar.h>
54 * A timecounter based on the free-running ACPI timer.
56 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
60 * Hooks for the ACPI CA debugging infrastructure
62 #define _COMPONENT ACPI_SYSTEM
63 ACPI_MODULE_NAME("TIMER")
65 static device_t acpi_timer_dev;
66 struct resource *acpi_timer_reg;
68 static u_int acpi_timer_frequency = 14318182/4;
70 static void acpi_timer_identify(driver_t *driver, device_t parent);
71 static int acpi_timer_probe(device_t dev);
72 static int acpi_timer_attach(device_t dev);
73 static unsigned acpi_timer_get_timecount(struct timecounter *tc);
74 static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
75 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
76 static void acpi_timer_test(void);
78 static u_int32_t read_counter(void);
79 static int test_counter(void);
82 * Driver hung off ACPI.
84 static device_method_t acpi_timer_methods[] = {
85 DEVMETHOD(device_identify, acpi_timer_identify),
86 DEVMETHOD(device_probe, acpi_timer_probe),
87 DEVMETHOD(device_attach, acpi_timer_attach),
92 static driver_t acpi_timer_driver = {
98 static devclass_t acpi_timer_devclass;
99 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
104 static struct timecounter acpi_timer_timecounter = {
105 acpi_timer_get_timecount_safe,
116 bus_space_handle_t bsh;
120 bsh = rman_get_bushandle(acpi_timer_reg);
121 bst = rman_get_bustag(acpi_timer_reg);
122 tv = bus_space_read_4(bst, bsh, 0);
123 bus_space_barrier(bst, bsh, 0, 4, BUS_SPACE_BARRIER_READ);
131 int min, max, n, delta;
136 last = read_counter();
137 for (n = 0; n < N; n++) {
138 this = read_counter();
139 delta = (this - last) & 0xffffff;
142 else if (delta < min)
148 else if (min < 0 || max == 0)
153 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
155 min, max, max - min);
160 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
164 acpi_timer_identify(driver_t *driver, device_t parent)
169 int i, j, rid, rtype;
171 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
173 if (acpi_disabled("timer"))
176 if (AcpiGbl_FADT == NULL)
179 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
180 device_printf(parent, "could not add acpi_timer0\n");
183 acpi_timer_dev = dev;
186 rlen = AcpiGbl_FADT->PmTmLen;
187 rtype = (AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId)
188 ? SYS_RES_IOPORT : SYS_RES_MEMORY;
189 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
190 bus_set_resource(dev, rtype, rid, rstart, rlen);
191 acpi_timer_reg = bus_alloc_resource(dev, rtype, &rid, 0, ~0, 1, RF_ACTIVE);
192 if (acpi_timer_reg == NULL) {
193 device_printf(dev, "couldn't allocate I/O resource (%s 0x%lx)\n",
194 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart);
197 if (testenv("debug.acpi.timer_test"))
200 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
202 for(i = 0; i < 10; i++)
205 acpi_timer_timecounter.tc_name = "ACPI-fast";
206 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
208 acpi_timer_timecounter.tc_name = "ACPI-safe";
209 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
211 tc_init(&acpi_timer_timecounter);
213 sprintf(desc, "%d-bit timer at 3.579545MHz", (AcpiGbl_FADT->TmrValExt)
215 device_set_desc_copy(dev, desc);
221 acpi_timer_probe(device_t dev)
223 if (dev == acpi_timer_dev)
229 acpi_timer_attach(device_t dev)
235 * Fetch current time value from reliable hardware.
238 acpi_timer_get_timecount(struct timecounter *tc)
240 return (read_counter());
244 * Fetch current time value from hardware that may not correctly
248 acpi_timer_get_timecount_safe(struct timecounter *tc)
258 } while (u1 > u2 || u2 > u3 || (u3 - u1) > 15);
263 * Timecounter freqency adjustment interface.
266 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
271 if (acpi_timer_timecounter.tc_frequency == 0)
273 freq = acpi_timer_frequency;
274 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
275 if (error == 0 && req->newptr != NULL) {
276 acpi_timer_frequency = freq;
277 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
282 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
283 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
286 * Test harness for verifying ACPI timer behaviour.
287 * Boot with debug.acpi.timer_test set to invoke this.
290 acpi_timer_test(void)
292 u_int32_t u1, u2, u3;
298 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
301 * The failure case is where u3 > u1, but u2 does not fall between the two,
302 * ie. it contains garbage.
305 if ((u2 < u1) || (u2 > u3))
306 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
316 * Chipset workaround driver hung off PCI.
318 * Some ACPI timers are known or believed to suffer from implementation
319 * problems which can lead to erroneous values being read from the timer.
321 * Since we can't trust unknown chipsets, we default to a timer-read
322 * routine which compensates for the most common problem (as detailed
323 * in the excerpt from the Intel PIIX4 datasheet below).
325 * When we detect a known-functional chipset, we disable the workaround
328 * ] 20. ACPI Timer Errata
330 * ] Problem: The power management timer may return improper result when
331 * ] read. Although the timer value settles properly after incrementing,
332 * ] while incrementing there is a 3nS window every 69.8nS where the
333 * ] timer value is indeterminate (a 4.2% chance that the data will be
334 * ] incorrect when read). As a result, the ACPI free running count up
335 * ] timer specification is violated due to erroneous reads. Implication:
336 * ] System hangs due to the "inaccuracy" of the timer when used by
337 * ] software for time critical events and delays.
339 * ] Workaround: Read the register twice and compare.
340 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
343 * The counter is in other words not latched to the PCI bus clock when
344 * read. Notice the workaround isn't: We need to read until we have
345 * three monotonic samples and then use the middle one, otherwise we are
346 * not protected against the fact that the bits can be wrong in two
347 * directions. If we only cared about monosity two reads would be enough.
351 static int acpi_timer_pci_probe(device_t dev);
353 static device_method_t acpi_timer_pci_methods[] = {
354 DEVMETHOD(device_probe, acpi_timer_pci_probe),
358 static driver_t acpi_timer_pci_driver = {
360 acpi_timer_pci_methods,
364 devclass_t acpi_timer_pci_devclass;
365 DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
368 * Look at PCI devices going past; if we detect one we know contains
369 * a functional ACPI timer device, enable the faster timecounter read
373 acpi_timer_pci_probe(device_t dev)
375 int vendor, device, revid;
377 vendor = pci_get_vendor(dev);
378 device = pci_get_device(dev);
379 revid = pci_get_revid(dev);
381 if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */
382 ((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */
385 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
386 acpi_timer_timecounter.tc_name = "ACPI-fast";
388 device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n");
391 return(ENXIO); /* we never match anything */