/*- * Copyright (c) 2000, 2001 Michael Smith * Copyright (c) 2000 BSDi * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD: head/sys/dev/acpica/acpi_timer.c 80070 2001-07-21 04:08:42Z msmith $ */ /* * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp * ---------------------------------------------------------------------------- */ #include "opt_acpi.h" #include #include #include #include #include #include #include #include #include #include "acpi.h" #include #include /* * A timecounter based on the free-running ACPI timer. * * Based on the i386-only mp_clock.c by . */ /* * Hooks for the ACPI CA debugging infrastructure */ #define _COMPONENT ACPI_SYSTEM MODULE_NAME("TIMER") static device_t acpi_timer_dev; struct resource *acpi_timer_reg; #define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \ rman_get_bushandle(acpi_timer_reg), \ 0) static int acpi_timer_flags; /* * ] 20. ACPI Timer Errata * ] * ] Problem: The power management timer may return improper result when * ] read. Although the timer value settles properly after incrementing, * ] while incrementing there is a 3nS window every 69.8nS where the * ] timer value is indeterminate (a 4.2% chance that the data will be * ] incorrect when read). As a result, the ACPI free running count up * ] timer specification is violated due to erroneous reads. Implication: * ] System hangs due to the "inaccuracy" of the timer when used by * ] software for time critical events and delays. * ] * ] Workaround: Read the register twice and compare. * ] Status: This will not be fixed in the PIIX4 or PIIX4E. * * The counter is in other words not latched to the PCI bus clock when * read. Notice the workaround isn't: We need to read until we have * three monotonic samples and then use the middle one, otherwise we are * not protected against the fact that the bits can be wrong in two * directions. If we only cared about monosity two reads would be enough. */ #define TFLAG_NEED_PIIX_WAR (1 << 0) static u_int acpi_timer_frequency = 14318182/4; static void acpi_timer_identify(driver_t *driver, device_t parent); static int acpi_timer_probe(device_t dev); static int acpi_timer_attach(device_t dev); static int acpi_timer_pci_probe(device_t dev); static unsigned acpi_timer_get_timecount(struct timecounter *tc); static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); static void acpi_timer_test(void); /* * Driver hung off ACPI. */ static device_method_t acpi_timer_methods[] = { DEVMETHOD(device_identify, acpi_timer_identify), DEVMETHOD(device_probe, acpi_timer_probe), DEVMETHOD(device_attach, acpi_timer_attach), {0, 0} }; static driver_t acpi_timer_driver = { "acpi_timer", acpi_timer_methods, 0, }; devclass_t acpi_timer_devclass; DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); /* * Chipset workaround driver hung off PCI. */ static device_method_t acpi_timer_pci_methods[] = { DEVMETHOD(device_probe, acpi_timer_pci_probe), {0, 0} }; static driver_t acpi_timer_pci_driver = { "acpi_timer_pci", acpi_timer_pci_methods, 0, }; devclass_t acpi_timer_pci_devclass; DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0); /* * Timecounter. */ static struct timecounter acpi_timer_timecounter = { acpi_timer_get_timecount, 0, 0xffffff, 0, "ACPI" }; SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD, &acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", ""); /* * Locate the ACPI timer using the FADT, set up and allocate the I/O resources * we will be using. */ static void acpi_timer_identify(driver_t *driver, device_t parent) { device_t dev; char desc[40]; int rid; FUNCTION_TRACE(__func__); if (acpi_disabled("timer")) return_VOID; if (AcpiGbl_FADT == NULL) return_VOID; if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { device_printf(parent, "could not add acpi_timer0\n"); return_VOID; } acpi_timer_dev = dev; rid = 0; bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t)); if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) { device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk); return_VOID; } if (getenv("debug.acpi.timer_test") != NULL) acpi_timer_test(); acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; tc_init(&acpi_timer_timecounter); sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24); device_set_desc_copy(dev, desc); return_VOID; } static int acpi_timer_probe(device_t dev) { if (dev == acpi_timer_dev) return(0); return(ENXIO); } static int acpi_timer_attach(device_t dev) { return(0); } /* * Look at PCI devices as they go past, and if we detect a PIIX4, set * the PIIX_WAR flag. * * XXX do we know that other timecounters work? Interesting question. */ static int acpi_timer_pci_probe(device_t dev) { if ((pci_get_vendor(dev) == 0x8086) && (pci_get_device(dev) == 0x7113)) { acpi_timer_flags |= TFLAG_NEED_PIIX_WAR; device_printf(acpi_timer_dev, "enabling PIIX4 timer workaround\n"); } return(ENXIO); /* we never match anything */ } /* * Fetch current time value from hardware. * * XXX This is currently written to be "correct", not * "fast". Optimisation is strongly indicated. */ static unsigned acpi_timer_get_timecount(struct timecounter *tc) { unsigned u1, u2, u3; if (acpi_timer_flags & TFLAG_NEED_PIIX_WAR) { u2 = TIMER_READ; u3 = TIMER_READ; do { u1 = u2; u2 = u3; u3 = TIMER_READ; } while (u1 > u2 || u2 > u3); return (u2); } else { return(TIMER_READ); } } /* * Timecounter freqency adjustment interface. */ static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) { int error; u_int freq; if (acpi_timer_timecounter.tc_frequency == 0) return (EOPNOTSUPP); freq = acpi_timer_frequency; error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); if (error == 0 && req->newptr != NULL) { acpi_timer_frequency = freq; acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; tc_update(&acpi_timer_timecounter); } return (error); } SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); /* * Test harness for verifying ACPI timer behaviour. * Boot with debug.acpi.timer_test set to invoke this. */ static void acpi_timer_test(void) { u_int32_t u1, u2, u3; u1 = TIMER_READ; u2 = TIMER_READ; u3 = TIMER_READ; device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); for (;;) { /* * The failure case is where u3 > u1, but u2 does not fall between the two, * ie. it contains garbage. */ if (u3 > u1) { if ((u2 < u1) || (u2 > u3)) device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", u1, u2, u3); } u1 = u2; u2 = u3; u3 = TIMER_READ; } }