From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Date: Thu, 06 Dec 2001 20:50:44 +0000 Subject: [Linux-ia64] multimedia timer interface Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org David, we talked awhile back about a generic timer interface that we could use on SN platforms as a non-drifting replacement for the ITC. I've taken a look at the Intel multimedia timer spec like you suggested and came up with the following header file. I've implemented it on our system with some glibc changes to the hp timing routines and things seem to work fine. I'd like to get people's comments on the ioctl interface though, because I'd like it to be useful on other platforms as well. Also, do you need me to resend the salinfo patch I posted awhile back or are you just waiting for the SAL spec to get updated? I noticed it wasn't in the latest patch. Thanks, Jesse /* * Intel Multimedia Timer device interface * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (c) 2001 Silicon Graphics, Inc. All rights reserved. * * This file should define an interface compatible with the IA-PC Multimedia * Timers Draft Specification (rev. 0.97) from Intel. Note that some * hardware may not be able to safely export its registers to userspace, * so the ioctl interface should support all necessary functionality. * * 11/01/01 - jbarnes - initial revision */ #ifndef _LINUX_MMTIMER_H /* name of the device, usually in /dev */ #define MMTIMER_NAME "mmtimer" #define MMTIMER_FULLNAME "/dev/mmtimer" #define MMTIMER_DESC "IA-PC Multimedia Timer" #define MMTIMER_VERSION "1.0" /* * Used by the user to setup an alarm */ typedef struct mmtimer_alarm { int id; unsigned long value; int signo; } mmtimer_alarm_t; /* * Breakdown of the ioctl's available. An 'optional' next to the command * indicates that supporting this command is optional, while 'required' * commands must be implemented if conformance is desired. * * MMTIMER_GETOFFSET - optional * Should return the offset (relative to the start of the page where the * registers are mapped) for the counter in question. * * MMTIMER_GETRES - required * The resolution of the clock in fempto (10E-15) seconds * * MMTIMER_GETFREQ - required * Frequency of the clock in Hz * * MMTIMER_GETLEGACYIRQ - required * Returns 1 if the device can route IRQs to legacy interrupt controllers * * MMTIMER_GETBITS - required * Number of bits in the clock's counter * * MMTIMER_GETNUM - required * Number of comparators available * * MMTIMER_MMAPAVAIL - required * Returns 1 if the registers can be mmap'd into userspace * * MMTIMER_SETPERIODIC - required * Sets the comparator in question to the value specified. * The interrupt handler will add the value specified to the * comparator after a match. * * MMTIMER_SETONESHOT - required * Like the above, but the comparator is not updated after the match. * * MMTIMER_GETCOUNTER - required * Gets the current value in the counter */ #define MMTIMER_IOCTL_BASE 'm' #define MMTIMER_GETOFFSET _IO(MMTIMER_IOCTL_BASE, 0) #define MMTIMER_GETRES _IOR(MMTIMER_IOCTL_BASE, 1, unsigned long) #define MMTIMER_GETFREQ _IOR(MMTIMER_IOCTL_BASE, 2, unsigned long) #define MMTIMER_GETLEGACYIRQ _IO(MMTIMER_IOCTL_BASE, 3) #define MMTIMER_GETBITS _IO(MMTIMER_IOCTL_BASE, 4) #define MMTIMER_GETNUM _IO(MMTIMER_IOCTL_BASE, 5) #define MMTIMER_MMAPAVAIL _IO(MMTIMER_IOCTL_BASE, 6) #define MMTIMER_SETPERIODIC _IOW(MMTIMER_IOCTL_BASE, 7, mmtimer_alarm_t) #define MMTIMER_SETONESHOT _IOW(MMTIMER_IOCTL_BASE, 8, mmtimer_alarm_t) #define MMTIMER_GETCOUNTER _IOR(MMTIMER_IOCTL_BASE, 9, unsigned long) /* * An mmtimer verification program. WARNINGs are ok, but ERRORs indicate * that the device doesn't fully support the interface defined here. */ #ifdef _MMTIMER_TEST_PROGRAM #include #include #include #include #include #include #include #include "mmtimer.h" int main(int argc, char *argv[]) { int result, fd; unsigned long val = 0; unsigned long i; if((fd = open("/dev/"MMTIMER_NAME, O_RDONLY)) = -1) { printf("failed to open /dev/%s", MMTIMER_NAME); return 1; } /* * How many comparators are there? */ if((result = ioctl(fd, MMTIMER_GETNUM, 0)) != -ENOSYS) printf("comparators available: %d\n", result); else printf("ERROR: no comparators available\n"); /* * Can we mmap in the counter? */ if((result = ioctl(fd, MMTIMER_MMAPAVAIL, 0)) = 1) { printf("mmap available\n"); /* ... so try getting the offset for each clock */ if((result = ioctl(fd, MMTIMER_GETOFFSET, 0)) != -ENOSYS) printf("offset: %d\n", result); else printf("WARNING: offset unavailable for clock\n"); } else printf("WARNING: mmap unavailable\n"); /* * Get the resolution in femptoseconds */ if((result = ioctl(fd, MMTIMER_GETRES, &val)) != -ENOSYS) printf("resolution: %ld femptoseconds\n", val); else printf("ERROR: failed to get resolution\n"); /* * Get the frequency in Hz */ if((result = ioctl(fd, MMTIMER_GETFREQ, &val)) != -ENOSYS) if(val < 10000000) /* less than 10 MHz? */ printf("ERROR: frequency only %ld MHz, should be >= 10 MHz\n", val/1000000); else printf("frequency: %ld MHz\n", val/1000000); else printf("ERROR: failed to get frequency\n"); /* * Does this interface have legacy IRQ support? */ if((result = ioctl(fd, MMTIMER_GETLEGACYIRQ, 0)) = 1) printf("legacy IRQ support available\n"); else printf("no legacy IRQ support available\n"); /* * How many bits in the counter? */ if((result = ioctl(fd, MMTIMER_GETBITS, 0)) != -ENOSYS) printf("bits in counter: %d\n", result); else printf("ERROR: can't get number of bits in counter\n"); if((result = ioctl(fd, MMTIMER_GETCOUNTER, &val)) != -ENOSYS) printf("counter value: %ld\n", val); else printf("ERROR: can't get counter value\n"); return 0; } #endif /* _MMTIMER_TEST_PROGRM */ #endif /* _LINUX_MMTIMER_H */