acpi_timer.c revision 80602
1/*- 2 * Copyright (c) 2000, 2001 Michael Smith 3 * Copyright (c) 2000 BSDi 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 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. 14 * 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 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD: head/sys/dev/acpica/acpi_timer.c 80602 2001-07-30 08:57:55Z msmith $ 28 */ 29#include "opt_acpi.h" 30#include <sys/param.h> 31#include <sys/bus.h> 32#include <sys/kernel.h> 33#include <sys/sysctl.h> 34#include <sys/timetc.h> 35 36#include <machine/bus_pio.h> 37#include <machine/bus.h> 38#include <machine/resource.h> 39#include <sys/rman.h> 40 41#include "acpi.h" 42 43#include <acpica/acpivar.h> 44#include <pci/pcivar.h> 45 46/* 47 * A timecounter based on the free-running ACPI timer. 48 * 49 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>. 50 */ 51 52/* 53 * Hooks for the ACPI CA debugging infrastructure 54 */ 55#define _COMPONENT ACPI_SYSTEM 56MODULE_NAME("TIMER") 57 58static device_t acpi_timer_dev; 59struct resource *acpi_timer_reg; 60#define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \ 61 rman_get_bushandle(acpi_timer_reg), \ 62 0) 63 64static u_int acpi_timer_frequency = 14318182/4; 65 66static void acpi_timer_identify(driver_t *driver, device_t parent); 67static int acpi_timer_probe(device_t dev); 68static int acpi_timer_attach(device_t dev); 69static unsigned acpi_timer_get_timecount(struct timecounter *tc); 70static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 71static void acpi_timer_test(void); 72 73/* 74 * Driver hung off ACPI. 75 */ 76static device_method_t acpi_timer_methods[] = { 77 DEVMETHOD(device_identify, acpi_timer_identify), 78 DEVMETHOD(device_probe, acpi_timer_probe), 79 DEVMETHOD(device_attach, acpi_timer_attach), 80 81 {0, 0} 82}; 83 84static driver_t acpi_timer_driver = { 85 "acpi_timer", 86 acpi_timer_methods, 87 0, 88}; 89 90devclass_t acpi_timer_devclass; 91DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 92 93/* 94 * Timecounter. 95 */ 96static struct timecounter acpi_timer_timecounter = { 97 acpi_timer_get_timecount, 98 0, 99 0xffffff, 100 0, 101 "ACPI" 102}; 103 104SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD, 105 &acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", ""); 106 107/* 108 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 109 * we will be using. 110 */ 111static void 112acpi_timer_identify(driver_t *driver, device_t parent) 113{ 114 device_t dev; 115 char desc[40]; 116 int rid; 117 118 FUNCTION_TRACE(__func__); 119 120 if (acpi_disabled("timer")) 121 return_VOID; 122 123 if (AcpiGbl_FADT == NULL) 124 return_VOID; 125 126 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 127 device_printf(parent, "could not add acpi_timer0\n"); 128 return_VOID; 129 } 130 acpi_timer_dev = dev; 131 rid = 0; 132 bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t)); 133 if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) { 134 device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk); 135 return_VOID; 136 } 137 if (getenv("debug.acpi.timer_test") != NULL) 138 acpi_timer_test(); 139 140 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 141 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 142 tc_init(&acpi_timer_timecounter); 143 144 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24); 145 device_set_desc_copy(dev, desc); 146 147 return_VOID; 148} 149 150static int 151acpi_timer_probe(device_t dev) 152{ 153 if (dev == acpi_timer_dev) 154 return(0); 155 return(ENXIO); 156} 157 158static int 159acpi_timer_attach(device_t dev) 160{ 161 return(0); 162} 163 164/* 165 * Fetch current time value from hardware. 166 */ 167static unsigned 168acpi_timer_get_timecount(struct timecounter *tc) 169{ 170 return(TIMER_READ); 171} 172 173/* 174 * Timecounter freqency adjustment interface. 175 */ 176static int 177acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 178{ 179 int error; 180 u_int freq; 181 182 if (acpi_timer_timecounter.tc_frequency == 0) 183 return (EOPNOTSUPP); 184 freq = acpi_timer_frequency; 185 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 186 if (error == 0 && req->newptr != NULL) { 187 acpi_timer_frequency = freq; 188 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 189 tc_update(&acpi_timer_timecounter); 190 } 191 return (error); 192} 193 194SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 195 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 196 197/* 198 * Test harness for verifying ACPI timer behaviour. 199 * Boot with debug.acpi.timer_test set to invoke this. 200 */ 201static void 202acpi_timer_test(void) 203{ 204 u_int32_t u1, u2, u3; 205 206 u1 = TIMER_READ; 207 u2 = TIMER_READ; 208 u3 = TIMER_READ; 209 210 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 211 for (;;) { 212 /* 213 * The failure case is where u3 > u1, but u2 does not fall between the two, 214 * ie. it contains garbage. 215 */ 216 if (u3 > u1) { 217 if ((u2 < u1) || (u2 > u3)) 218 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 219 u1, u2, u3); 220 } 221 u1 = u2; 222 u2 = u3; 223 u3 = TIMER_READ; 224 } 225} 226 227/* 228 * Chipset workaround driver hung off PCI. 229 * 230 * ] 20. ACPI Timer Errata 231 * ] 232 * ] Problem: The power management timer may return improper result when 233 * ] read. Although the timer value settles properly after incrementing, 234 * ] while incrementing there is a 3nS window every 69.8nS where the 235 * ] timer value is indeterminate (a 4.2% chance that the data will be 236 * ] incorrect when read). As a result, the ACPI free running count up 237 * ] timer specification is violated due to erroneous reads. Implication: 238 * ] System hangs due to the "inaccuracy" of the timer when used by 239 * ] software for time critical events and delays. 240 * ] 241 * ] Workaround: Read the register twice and compare. 242 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 243 * ] in the PIIX4M. 244 * 245 * The counter is in other words not latched to the PCI bus clock when 246 * read. Notice the workaround isn't: We need to read until we have 247 * three monotonic samples and then use the middle one, otherwise we are 248 * not protected against the fact that the bits can be wrong in two 249 * directions. If we only cared about monosity two reads would be enough. 250 */ 251 252static int acpi_timer_pci_probe(device_t dev); 253static unsigned acpi_timer_get_timecount_piix(struct timecounter *tc); 254 255static device_method_t acpi_timer_pci_methods[] = { 256 DEVMETHOD(device_probe, acpi_timer_pci_probe), 257 {0, 0} 258}; 259 260static driver_t acpi_timer_pci_driver = { 261 "acpi_timer_pci", 262 acpi_timer_pci_methods, 263 0, 264}; 265 266devclass_t acpi_timer_pci_devclass; 267DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0); 268 269/* 270 * Look at PCI devices as they go past, and if we detect a PIIX4 older than 271 * the PIIX4M, use an alternate get_timecount routine. 272 * 273 * XXX do we know that other timecounters work? Perhaps we should test them? 274 */ 275static int 276acpi_timer_pci_probe(device_t dev) 277{ 278 if ((pci_get_vendor(dev) == 0x8086) && 279 (pci_get_device(dev) == 0x7113) && 280 (pci_get_revid(dev) < 0x03)) { 281 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_piix; 282 acpi_timer_timecounter.tc_name = "ACPI-PIIX"; 283 device_printf(acpi_timer_dev, "enabling PIIX4 timer workaround\n"); 284 } 285 286 return(ENXIO); /* we never match anything */ 287} 288 289/* 290 * Read the buggy PIIX4 ACPI timer and compensate for its behaviour. 291 */ 292static unsigned 293acpi_timer_get_timecount_piix(struct timecounter *tc) 294{ 295 unsigned u1, u2, u3; 296 297 u2 = TIMER_READ; 298 u3 = TIMER_READ; 299 do { 300 u1 = u2; 301 u2 = u3; 302 u3 = TIMER_READ; 303 } while (u1 > u2 || u2 > u3); 304 return (u2); 305} 306 307