X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2Fhpet.txt;h=b7a3dc38dd524777f67bd185c1fabcf867015326;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=4e7cc8d3359b9a839ed941d5dbad01598869c306;hpb=9bf4aaab3e101692164d49b7ca357651eb691cb6;p=linux-2.6.git diff --git a/Documentation/hpet.txt b/Documentation/hpet.txt index 4e7cc8d33..b7a3dc38d 100644 --- a/Documentation/hpet.txt +++ b/Documentation/hpet.txt @@ -1,18 +1,21 @@ 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 two 32 timers. It is possible -to configure the first two timers as legacy replacements for 8254 and RTC periodic. A specification -done by INTEL and Microsoft can be found at http://www.intel.com/labs/platcomp/hpet/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 +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 +. + +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. +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 #include @@ -290,9 +293,8 @@ The kernel API has three interfaces exported from the driver: 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 +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. - -