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
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/module.h>
36 #include <sys/sysctl.h>
37 #include <sys/timetc.h>
39 #include <machine/bus.h>
40 #include <machine/resource.h>
43 #include <contrib/dev/acpica/include/acpi.h>
44 #include <contrib/dev/acpica/include/accommon.h>
46 #include <dev/acpica/acpivar.h>
47 #include <dev/pci/pcivar.h>
50 * A timecounter based on the free-running ACPI timer.
52 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
55 /* Hooks for the ACPI CA debugging infrastructure */
56 #define _COMPONENT ACPI_TIMER
57 ACPI_MODULE_NAME("TIMER")
59 static device_t acpi_timer_dev;
60 static struct resource *acpi_timer_reg;
61 static bus_space_handle_t acpi_timer_bsh;
62 static bus_space_tag_t acpi_timer_bst;
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 u_int acpi_timer_get_timecount(struct timecounter *tc);
70 static u_int acpi_timer_get_timecount_safe(struct timecounter *tc);
71 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
72 static void acpi_timer_boot_test(void);
74 static u_int acpi_timer_read(void);
75 static int acpi_timer_test(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);
93 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
95 static struct timecounter acpi_timer_timecounter = {
96 acpi_timer_get_timecount_safe, /* get_timecount function */
98 0, /* no default counter_mask */
99 0, /* no default frequency */
101 -1 /* quality (chosen later) */
107 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
111 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
115 acpi_timer_identify(driver_t *driver, device_t parent)
121 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
123 if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) ||
127 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
128 device_printf(parent, "could not add acpi_timer0\n");
131 acpi_timer_dev = dev;
134 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
135 SYS_RES_IOPORT : SYS_RES_MEMORY;
136 rlen = AcpiGbl_FADT.PmTimerLength;
137 rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
138 if (bus_set_resource(dev, rtype, rid, rstart, rlen))
139 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
140 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
145 acpi_timer_probe(device_t dev)
148 int i, j, rid, rtype;
150 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
152 if (dev != acpi_timer_dev)
156 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
157 SYS_RES_IOPORT : SYS_RES_MEMORY;
158 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
159 if (acpi_timer_reg == NULL) {
160 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
161 (rtype == SYS_RES_IOPORT) ? "port" : "mem",
162 (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
165 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
166 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
167 if (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER)
168 acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
170 acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
171 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
172 if (testenv("debug.acpi.timer_test"))
173 acpi_timer_boot_test();
176 * If all tests of the counter succeed, use the ACPI-fast method. If
177 * at least one failed, default to using the safe routine, which reads
178 * the timer multiple times to get a consistent value before returning.
182 printf("ACPI timer:");
183 for (i = 0; i < 10; i++)
184 j += acpi_timer_test();
186 printf(" -> %d\n", j);
188 acpi_timer_timecounter.tc_name = "ACPI-fast";
189 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
190 acpi_timer_timecounter.tc_quality = 1000;
192 acpi_timer_timecounter.tc_name = "ACPI-safe";
193 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
194 acpi_timer_timecounter.tc_quality = 850;
196 tc_init(&acpi_timer_timecounter);
198 sprintf(desc, "%d-bit timer at 3.579545MHz",
199 (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
200 device_set_desc_copy(dev, desc);
202 /* Release the resource, we'll allocate it again during attach. */
203 bus_release_resource(dev, rtype, rid, acpi_timer_reg);
208 acpi_timer_attach(device_t dev)
212 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
215 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
216 SYS_RES_IOPORT : SYS_RES_MEMORY;
217 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
218 if (acpi_timer_reg == NULL)
220 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
221 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
226 * Fetch current time value from reliable hardware.
229 acpi_timer_get_timecount(struct timecounter *tc)
231 return (acpi_timer_read());
235 * Fetch current time value from hardware that may not correctly
236 * latch the counter. We need to read until we have three monotonic
237 * samples and then use the middle one, otherwise we are not protected
238 * against the fact that the bits can be wrong in two directions. If
239 * we only cared about monosity, two reads would be enough.
242 acpi_timer_get_timecount_safe(struct timecounter *tc)
246 u2 = acpi_timer_read();
247 u3 = acpi_timer_read();
251 u3 = acpi_timer_read();
252 } while (u1 > u2 || u2 > u3);
258 * Timecounter freqency adjustment interface.
261 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
266 if (acpi_timer_timecounter.tc_frequency == 0)
268 freq = acpi_timer_frequency;
269 error = sysctl_handle_int(oidp, &freq, 0, req);
270 if (error == 0 && req->newptr != NULL) {
271 acpi_timer_frequency = freq;
272 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
278 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
279 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
282 * Some ACPI timers are known or believed to suffer from implementation
283 * problems which can lead to erroneous values being read. This function
284 * tests for consistent results from the timer and returns 1 if it believes
285 * the timer is consistent, otherwise it returns 0.
287 * It appears the cause is that the counter is not latched to the PCI bus
290 * ] 20. ACPI Timer Errata
292 * ] Problem: The power management timer may return improper result when
293 * ] read. Although the timer value settles properly after incrementing,
294 * ] while incrementing there is a 3nS window every 69.8nS where the
295 * ] timer value is indeterminate (a 4.2% chance that the data will be
296 * ] incorrect when read). As a result, the ACPI free running count up
297 * ] timer specification is violated due to erroneous reads. Implication:
298 * ] System hangs due to the "inaccuracy" of the timer when used by
299 * ] software for time critical events and delays.
301 * ] Workaround: Read the register twice and compare.
302 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
310 int min, max, n, delta;
316 /* Test the timer with interrupts disabled to get accurate results. */
318 last = acpi_timer_read();
319 for (n = 0; n < N; n++) {
320 this = acpi_timer_read();
321 delta = acpi_TimerDelta(this, last);
324 else if (delta < min)
332 else if (min < 0 || max == 0)
337 printf(" %d/%d", n, max-min);
344 * Test harness for verifying ACPI timer behaviour.
345 * Boot with debug.acpi.timer_test set to invoke this.
348 acpi_timer_boot_test(void)
352 u1 = acpi_timer_read();
353 u2 = acpi_timer_read();
354 u3 = acpi_timer_read();
356 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
359 * The failure case is where u3 > u1, but u2 does not fall between
360 * the two, ie. it contains garbage.
363 if (u2 < u1 || u2 > u3)
364 device_printf(acpi_timer_dev,
365 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
370 u3 = acpi_timer_read();