summaryrefslogtreecommitdiff
path: root/Documentation/hpet.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/hpet.txt')
-rw-r--r--Documentation/hpet.txt300
1 files changed, 0 insertions, 300 deletions
diff --git a/Documentation/hpet.txt b/Documentation/hpet.txt
deleted file mode 100644
index 6ad52d9dad6c..000000000000
--- a/Documentation/hpet.txt
+++ /dev/null
@@ -1,300 +0,0 @@
- High Precision Event Timer Driver for Linux
-
-The High Precision Event Timer (HPET) hardware is the future replacement
-for the 8254 and Real Time Clock (RTC) periodic timer functionality.
-Each HPET can have up to 32 timers. It is possible to configure the
-first two timers as legacy replacements for 8254 and RTC periodic timers.
-A specification done by Intel and Microsoft can be found at
-<http://www.intel.com/technology/architecture/hpetspec.htm>.
-
-The driver supports detection of HPET driver allocation and initialization
-of the HPET before the driver module_init routine is called. This enables
-platform code which uses timer 0 or 1 as the main timer to intercept HPET
-initialization. An example of this initialization can be found in
-arch/i386/kernel/time_hpet.c.
-
-The driver provides two APIs which are very similar to the API found in
-the rtc.c driver. There is a user space API and a kernel space API.
-An example user space program is provided below.
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <string.h>
-#include <memory.h>
-#include <malloc.h>
-#include <time.h>
-#include <ctype.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <signal.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <sys/time.h>
-#include <linux/hpet.h>
-
-
-extern void hpet_open_close(int, const char **);
-extern void hpet_info(int, const char **);
-extern void hpet_poll(int, const char **);
-extern void hpet_fasync(int, const char **);
-extern void hpet_read(int, const char **);
-
-#include <sys/poll.h>
-#include <sys/ioctl.h>
-#include <signal.h>
-
-struct hpet_command {
- char *command;
- void (*func)(int argc, const char ** argv);
-} hpet_command[] = {
- {
- "open-close",
- hpet_open_close
- },
- {
- "info",
- hpet_info
- },
- {
- "poll",
- hpet_poll
- },
- {
- "fasync",
- hpet_fasync
- },
-};
-
-int
-main(int argc, const char ** argv)
-{
- int i;
-
- argc--;
- argv++;
-
- if (!argc) {
- fprintf(stderr, "-hpet: requires command\n");
- return -1;
- }
-
-
- for (i = 0; i < (sizeof (hpet_command) / sizeof (hpet_command[0])); i++)
- if (!strcmp(argv[0], hpet_command[i].command)) {
- argc--;
- argv++;
- fprintf(stderr, "-hpet: executing %s\n",
- hpet_command[i].command);
- hpet_command[i].func(argc, argv);
- return 0;
- }
-
- fprintf(stderr, "do_hpet: command %s not implemented\n", argv[0]);
-
- return -1;
-}
-
-void
-hpet_open_close(int argc, const char **argv)
-{
- int fd;
-
- if (argc != 1) {
- fprintf(stderr, "hpet_open_close: device-name\n");
- return;
- }
-
- fd = open(argv[0], O_RDONLY);
- if (fd < 0)
- fprintf(stderr, "hpet_open_close: open failed\n");
- else
- close(fd);
-
- return;
-}
-
-void
-hpet_info(int argc, const char **argv)
-{
-}
-
-void
-hpet_poll(int argc, const char **argv)
-{
- unsigned long freq;
- int iterations, i, fd;
- struct pollfd pfd;
- struct hpet_info info;
- struct timeval stv, etv;
- struct timezone tz;
- long usec;
-
- if (argc != 3) {
- fprintf(stderr, "hpet_poll: device-name freq iterations\n");
- return;
- }
-
- freq = atoi(argv[1]);
- iterations = atoi(argv[2]);
-
- fd = open(argv[0], O_RDONLY);
-
- if (fd < 0) {
- fprintf(stderr, "hpet_poll: open of %s failed\n", argv[0]);
- return;
- }
-
- if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
- fprintf(stderr, "hpet_poll: HPET_IRQFREQ failed\n");
- goto out;
- }
-
- if (ioctl(fd, HPET_INFO, &info) < 0) {
- fprintf(stderr, "hpet_poll: failed to get info\n");
- goto out;
- }
-
- fprintf(stderr, "hpet_poll: info.hi_flags 0x%lx\n", info.hi_flags);
-
- if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
- fprintf(stderr, "hpet_poll: HPET_EPI failed\n");
- goto out;
- }
-
- if (ioctl(fd, HPET_IE_ON, 0) < 0) {
- fprintf(stderr, "hpet_poll, HPET_IE_ON failed\n");
- goto out;
- }
-
- pfd.fd = fd;
- pfd.events = POLLIN;
-
- for (i = 0; i < iterations; i++) {
- pfd.revents = 0;
- gettimeofday(&stv, &tz);
- if (poll(&pfd, 1, -1) < 0)
- fprintf(stderr, "hpet_poll: poll failed\n");
- else {
- long data;
-
- gettimeofday(&etv, &tz);
- usec = stv.tv_sec * 1000000 + stv.tv_usec;
- usec = (etv.tv_sec * 1000000 + etv.tv_usec) - usec;
-
- fprintf(stderr,
- "hpet_poll: expired time = 0x%lx\n", usec);
-
- fprintf(stderr, "hpet_poll: revents = 0x%x\n",
- pfd.revents);
-
- if (read(fd, &data, sizeof(data)) != sizeof(data)) {
- fprintf(stderr, "hpet_poll: read failed\n");
- }
- else
- fprintf(stderr, "hpet_poll: data 0x%lx\n",
- data);
- }
- }
-
-out:
- close(fd);
- return;
-}
-
-static int hpet_sigio_count;
-
-static void
-hpet_sigio(int val)
-{
- fprintf(stderr, "hpet_sigio: called\n");
- hpet_sigio_count++;
-}
-
-void
-hpet_fasync(int argc, const char **argv)
-{
- unsigned long freq;
- int iterations, i, fd, value;
- sig_t oldsig;
- struct hpet_info info;
-
- hpet_sigio_count = 0;
- fd = -1;
-
- if ((oldsig = signal(SIGIO, hpet_sigio)) == SIG_ERR) {
- fprintf(stderr, "hpet_fasync: failed to set signal handler\n");
- return;
- }
-
- if (argc != 3) {
- fprintf(stderr, "hpet_fasync: device-name freq iterations\n");
- goto out;
- }
-
- fd = open(argv[0], O_RDONLY);
-
- if (fd < 0) {
- fprintf(stderr, "hpet_fasync: failed to open %s\n", argv[0]);
- return;
- }
-
-
- if ((fcntl(fd, F_SETOWN, getpid()) == 1) ||
- ((value = fcntl(fd, F_GETFL)) == 1) ||
- (fcntl(fd, F_SETFL, value | O_ASYNC) == 1)) {
- fprintf(stderr, "hpet_fasync: fcntl failed\n");
- goto out;
- }
-
- freq = atoi(argv[1]);
- iterations = atoi(argv[2]);
-
- if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
- fprintf(stderr, "hpet_fasync: HPET_IRQFREQ failed\n");
- goto out;
- }
-
- if (ioctl(fd, HPET_INFO, &info) < 0) {
- fprintf(stderr, "hpet_fasync: failed to get info\n");
- goto out;
- }
-
- fprintf(stderr, "hpet_fasync: info.hi_flags 0x%lx\n", info.hi_flags);
-
- if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
- fprintf(stderr, "hpet_fasync: HPET_EPI failed\n");
- goto out;
- }
-
- if (ioctl(fd, HPET_IE_ON, 0) < 0) {
- fprintf(stderr, "hpet_fasync, HPET_IE_ON failed\n");
- goto out;
- }
-
- for (i = 0; i < iterations; i++) {
- (void) pause();
- fprintf(stderr, "hpet_fasync: count = %d\n", hpet_sigio_count);
- }
-
-out:
- signal(SIGIO, oldsig);
-
- if (fd >= 0)
- close(fd);
-
- return;
-}
-
-The kernel API has three interfaces exported from the driver:
-
- hpet_register(struct hpet_task *tp, int periodic)
- hpet_unregister(struct hpet_task *tp)
- hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
-
-The kernel module using this interface fills in the ht_func and ht_data
-members of the hpet_task structure before calling hpet_register.
-hpet_control simply vectors to the hpet_ioctl routine and has the same
-commands and respective arguments as the user API. hpet_unregister
-is used to terminate usage of the HPET timer reserved by hpet_register.
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-25 04:16:28 +0300