Fix several bugs where 32-bit timers and wraparound were not properly
supported. Symptoms of this bug included unnecessary use of ACPI-safe and a dmesg that has deltas of about 2^24: ACPI timer looks BAD min = 2, max = 16777206, width = 16777204 ACPI timer looks BAD min = 2, max = 7, width = 5 ACPI timer looks GOOD min = 4, max = 5, width = 1 ACPI timer looks BAD min = 2, max = 16777206, width = 16777204 ACPI timer looks BAD min = 2, max = 7, width = 5 ACPI timer looks BAD min = 2, max = 16777210, width = 16777208 ACPI timer looks BAD min = 4, max = 16777189, width = 16777185 ACPI timer looks GOOD min = 4, max = 5, width = 1 ACPI timer looks BAD min = 2, max = 7, width = 5 ACPI timer looks BAD min = 4, max = 16777189, width = 16777185 To fix this: * Use a 32 bit timecounter mask when the timer is 32 bits. * In test_counter(), use the acpi_TimerDelta function which handles 24/32 bit timers and wraparound. Miscellaneous fixes: * Use C99 initializers for timecounter struct. * Use u_int and uint32_t where appropriate instead of unsigned. * Remove whitespace-only lines * Remove the old PIIX4 PCI workaround. The timecounter testing code has been in use for long enough to prove it's functional.
This commit is contained in:
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47d91ba394
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75988358a2
@ -31,11 +31,7 @@
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#if __FreeBSD_version >= 500000
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#include <sys/timetc.h>
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#else
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#include <sys/time.h>
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#endif
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#include <machine/bus.h>
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#include <machine/resource.h>
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@ -63,12 +59,12 @@ static u_int acpi_timer_frequency = 14318182 / 4;
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static void acpi_timer_identify(driver_t *driver, device_t parent);
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static int acpi_timer_probe(device_t dev);
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static int acpi_timer_attach(device_t dev);
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static unsigned acpi_timer_get_timecount(struct timecounter *tc);
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static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
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static u_int acpi_timer_get_timecount(struct timecounter *tc);
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static u_int acpi_timer_get_timecount_safe(struct timecounter *tc);
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static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
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static void acpi_timer_test(void);
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static uint32_t read_counter(void);
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static u_int read_counter(void);
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static int test_counter(void);
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static device_method_t acpi_timer_methods[] = {
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@ -90,20 +86,20 @@ DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
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MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
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static struct timecounter acpi_timer_timecounter = {
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acpi_timer_get_timecount_safe,
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0,
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0xffffff,
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0,
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"ACPI",
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1000
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.tc_get_timecount = acpi_timer_get_timecount_safe,
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.tc_poll_pps = 0,
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.tc_counter_mask = 0,
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.tc_frequency = 0,
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.tc_name = "ACPI",
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.tc_quality = 1000
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};
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static uint32_t
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static u_int
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read_counter()
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{
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bus_space_handle_t bsh;
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bus_space_tag_t bst;
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u_int32_t tv;
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uint32_t tv;
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bsh = rman_get_bushandle(acpi_timer_reg);
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bst = rman_get_bustag(acpi_timer_reg);
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@ -117,7 +113,7 @@ read_counter()
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static int
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test_counter()
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{
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u_int last, this;
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uint32_t last, this;
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int min, max, n, delta;
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min = 10000000;
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@ -125,7 +121,7 @@ test_counter()
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last = read_counter();
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for (n = 0; n < N; n++) {
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this = read_counter();
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delta = (this - last) & 0xffffff;
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delta = acpi_TimerDelta(this, last);
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if (delta > max)
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max = delta;
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else if (delta < min)
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@ -164,7 +160,7 @@ acpi_timer_identify(driver_t *driver, device_t parent)
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if (acpi_disabled("timer") || AcpiGbl_FADT == NULL)
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return_VOID;
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if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
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device_printf(parent, "could not add acpi_timer0\n");
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return_VOID;
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@ -183,12 +179,16 @@ acpi_timer_identify(driver_t *driver, device_t parent)
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rtype == SYS_RES_IOPORT ? "port" : "mem", rstart);
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return_VOID;
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}
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if (AcpiGbl_FADT->TmrValExt != 0)
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acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
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else
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acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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if (testenv("debug.acpi.timer_test"))
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acpi_timer_test();
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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j = 0;
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for(i = 0; i < 10; i++)
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for (i = 0; i < 10; i++)
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j += test_counter();
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if (j == 10) {
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acpi_timer_timecounter.tc_name = "ACPI-fast";
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@ -224,7 +224,7 @@ acpi_timer_attach(device_t dev)
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/*
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* Fetch current time value from reliable hardware.
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*/
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static unsigned
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static u_int
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acpi_timer_get_timecount(struct timecounter *tc)
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{
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return (read_counter());
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@ -234,10 +234,10 @@ acpi_timer_get_timecount(struct timecounter *tc)
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* Fetch current time value from hardware that may not correctly
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* latch the counter.
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*/
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static unsigned
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static u_int
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acpi_timer_get_timecount_safe(struct timecounter *tc)
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{
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unsigned u1, u2, u3;
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u_int u1, u2, u3;
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u2 = read_counter();
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u3 = read_counter();
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@ -281,12 +281,12 @@ SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
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static void
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acpi_timer_test(void)
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{
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u_int32_t u1, u2, u3;
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uint32_t u1, u2, u3;
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u1 = read_counter();
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u2 = read_counter();
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u3 = read_counter();
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device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
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for (;;) {
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/*
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@ -304,87 +304,3 @@ acpi_timer_test(void)
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u3 = read_counter();
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}
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}
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/*
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* Chipset workaround driver hung off PCI.
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*
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* Some ACPI timers are known or believed to suffer from implementation
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* problems which can lead to erroneous values being read from the timer.
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*
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* Since we can't trust unknown chipsets, we default to a timer-read
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* routine which compensates for the most common problem (as detailed
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* in the excerpt from the Intel PIIX4 datasheet below).
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*
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* When we detect a known-functional chipset, we disable the workaround
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* to improve speed.
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*
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* ] 20. ACPI Timer Errata
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* ]
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* ] Problem: The power management timer may return improper result when
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* ] read. Although the timer value settles properly after incrementing,
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* ] while incrementing there is a 3nS window every 69.8nS where the
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* ] timer value is indeterminate (a 4.2% chance that the data will be
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* ] incorrect when read). As a result, the ACPI free running count up
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* ] timer specification is violated due to erroneous reads. Implication:
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* ] System hangs due to the "inaccuracy" of the timer when used by
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* ] software for time critical events and delays.
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* ]
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* ] Workaround: Read the register twice and compare.
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* ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
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* ] in the PIIX4M.
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*
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* The counter is in other words not latched to the PCI bus clock when
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* read. Notice the workaround isn't: We need to read until we have
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* three monotonic samples and then use the middle one, otherwise we are
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* not protected against the fact that the bits can be wrong in two
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* directions. If we only cared about monosity two reads would be enough.
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*/
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#if 0
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static int acpi_timer_pci_probe(device_t dev);
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static device_method_t acpi_timer_pci_methods[] = {
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DEVMETHOD(device_probe, acpi_timer_pci_probe),
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{0, 0}
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};
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static driver_t acpi_timer_pci_driver = {
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"acpi_timer_pci",
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acpi_timer_pci_methods,
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0,
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};
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devclass_t acpi_timer_pci_devclass;
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DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver,
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acpi_timer_pci_devclass, 0, 0);
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/*
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* Look at PCI devices going past; if we detect one we know contains
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* a functional ACPI timer device, enable the faster timecounter read
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* routine.
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*/
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static int
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acpi_timer_pci_probe(device_t dev)
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{
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int vendor, device, revid;
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vendor = pci_get_vendor(dev);
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device = pci_get_device(dev);
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revid = pci_get_revid(dev);
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/* Detect the PIIX4M and i440MX, respectively */
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if ((vendor == 0x8086 && device == 0x7113 && revid >= 0x03) ||
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(vendor == 0x8086 && device == 0x719b)) {
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acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
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acpi_timer_timecounter.tc_name = "ACPI-fast";
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if (bootverbose) {
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device_printf(acpi_timer_dev,"functional ACPI timer detected, "
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"enabling fast timecount interface\n");
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}
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}
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/* We never match anything */
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return (ENXIO);
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}
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#endif
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