From: bennett78 <bennett78@digis•net>
To: Wolfgang Denk <wd@denx•de>
Cc: linuxppc-embedded@ozlabs•org
Subject: MPC5200 RTC
Date: Tue, 13 Dec 2005 11:10:35 -0700 [thread overview]
Message-ID: <439F0E9B.30600@digis.net> (raw)
In-Reply-To: <20051207195112.06457353A66@atlas.denx.de>
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* The /dev/rtc interface will block on reads until an interrupt
* has been received. If a RTC interrupt has already happened,
* it will output an unsigned long and then block.
Paul Gortmaker's rtctest (included below) works really well on my x86
machine (driver/char/rtc.c) as a nice way for a user process to wait on
ticks
of a programable frequency (via ioctl).
Under Denx linuxppc_2_4_devel MPC5200 I've tried:
driver/char/rtc.c - kernel panics
seems to need a RTC_IRQ to be defined
include/linux/mc14681rtc.h mentions #define RTC_IRQ 8 ?
CONFIG_PPC_RTC also panics
driver/char/genrtc.c (with #define CONFIG_GEN_RTC_X)
sort of works but I get the following:
gen_rtc_interrupt: system delaying clock ticks?
The internal MPC5200 RTC doesn't seem supported.
I see a lot of references to external RTCs, probably because
the standby power for the 5200 is high. I would like to
use a timer as the RTC interrupt and add an external RTC
later as a time reference (none on Lite5200 dev brd).
How best can I assign a GPTx as an interrupt? other than re-write
genrtc.c?
thanks,
Frank Bennett
*//*
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[-- Attachment #2: rtctest.c --]
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/*
* Real Time Clock Driver Test/Example Program
*
* Compile with:
* gcc -s -Wall -Wstrict-prototypes rtctest.c -o rtctest
*
* Copyright (C) 1996, Paul Gortmaker.
*
* Released under the GNU General Public License, version 2,
* included herein by reference.
*
*/
#define spinlock_t int
#include <stdio.h>
#include <linux/mc146818rtc.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
void main(void) {
int i, fd, retval, irqcount = 0;
unsigned long tmp, data;
struct rtc_time rtc_tm;
fd = open ("/dev/rtc", O_RDONLY);
if (fd == -1) {
perror("/dev/rtc");
exit(errno);
}
fprintf(stderr, "\n\t\t\tRTC Driver Test Example.\n\n");
/* Turn on update interrupts (one per second) */
retval = ioctl(fd, RTC_UIE_ON, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading /dev/rtc:");
fflush(stderr);
for (i=1; i<6; i++) {
/* This read will block */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -1) {
perror("read");
exit(errno);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
fprintf(stderr, "\nAgain, from using select(2) on /dev/rtc:");
fflush(stderr);
for (i=1; i<6; i++) {
struct timeval tv = {5, 0}; /* 5 second timeout on select */
fd_set readfds;
FD_ZERO(&readfds);
FD_SET(fd, &readfds);
/* The select will wait until an RTC interrupt happens. */
retval = select(fd+1, &readfds, NULL, NULL, &tv);
if (retval == -1) {
perror("select");
exit(errno);
}
/* This read won't block unlike the select-less case above. */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -1) {
perror("read");
exit(errno);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
/* Turn off update interrupts */
retval = ioctl(fd, RTC_UIE_OFF, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
/* Read the RTC time/date */
retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "\n\nCurrent RTC date/time is %d-%d-%d, %02d:%02d:%02d.\n",
rtc_tm.tm_mday, rtc_tm.tm_mon + 1, rtc_tm.tm_year + 1900,
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);
/* Set the alarm to 5 sec in the future, and check for rollover */
rtc_tm.tm_sec += 5;
if (rtc_tm.tm_sec >= 60) {
rtc_tm.tm_sec %= 60;
rtc_tm.tm_min++;
}
if (rtc_tm.tm_min == 60) {
rtc_tm.tm_min = 0;
rtc_tm.tm_hour++;
}
if (rtc_tm.tm_hour == 24)
rtc_tm.tm_hour = 0;
retval = ioctl(fd, RTC_ALM_SET, &rtc_tm);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
/* Read the current alarm settings */
retval = ioctl(fd, RTC_ALM_READ, &rtc_tm);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "Alarm time now set to %02d:%02d:%02d.\n",
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);
/* Enable alarm interrupts */
retval = ioctl(fd, RTC_AIE_ON, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "Waiting 5 seconds for alarm...");
fflush(stderr);
/* This blocks until the alarm ring causes an interrupt */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -1) {
perror("read");
exit(errno);
}
irqcount++;
fprintf(stderr, " okay. Alarm rang.\n");
/* Disable alarm interrupts */
retval = ioctl(fd, RTC_AIE_OFF, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
/* Read periodic IRQ rate */
retval = ioctl(fd, RTC_IRQP_READ, &tmp);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "\nPeriodic IRQ rate was %ldHz.\n", tmp);
fprintf(stderr, "Counting 20 interrupts at:");
fflush(stderr);
/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */
for (tmp=2; tmp<=64; tmp*=2) {
retval = ioctl(fd, RTC_IRQP_SET, tmp);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
fprintf(stderr, "\n%ldHz:\t", tmp);
fflush(stderr);
/* Enable periodic interrupts */
retval = ioctl(fd, RTC_PIE_ON, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
for (i=1; i<21; i++) {
/* This blocks */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -1) {
perror("read");
exit(errno);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
/* Disable periodic interrupts */
retval = ioctl(fd, RTC_PIE_OFF, 0);
if (retval == -1) {
perror("ioctl");
exit(errno);
}
}
fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");
fprintf(stderr, "\nTyping \"cat /proc/interrupts\" will show %d more events on IRQ 8.\n\n",
irqcount);
close(fd);
} /* end main */
next prev parent reply other threads:[~2005-12-13 18:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-05 19:30 Video Card to Lite5200 Alan Carvalho
2005-12-05 20:35 ` Wolfgang Denk
2005-12-05 20:39 ` Alessandro Rubini
2005-12-07 17:23 ` roger blofeld
2005-12-07 18:53 ` Alan Carvalho
2005-12-07 19:51 ` Wolfgang Denk
2005-12-13 18:10 ` bennett78 [this message]
2006-06-30 23:16 ` Benjamin Herrenschmidt
2006-07-01 9:15 ` Wolfgang Denk
2006-07-01 9:29 ` Benjamin Herrenschmidt
2005-12-08 0:25 ` Alessandro Rubini
2005-12-08 5:59 ` White
2005-12-08 23:10 ` Wolfgang Denk
2005-12-09 11:49 ` Andrey Volkov
2005-12-07 21:23 ` bennett78
2005-12-07 22:53 ` Wolfgang Denk
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