/**************************************************************************
*
* Copyright (c) 2013 Alcatel-Lucent
*
* Alcatel Lucent licenses this file to You under the Apache License,
* Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. A copy of the License is contained the
* file LICENSE at the top level of this repository.
* You may also obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
**************************************************************************
*
* timestuff.c
*
* These functions support the monitor's ability to deal with elapsed
* time on targets with or without hardware-timer support.
*
* The INCLUDE_HWTMR definition in config.h determines which mode
* the timer will run in.
*
* The monitor does not require any hardware-assist for maintaining
* elapsed time. With no hardware assist (INCLUDE_HWTMR set to 0),
* the value of LOOPS_PER_SECOND must be established in config.h, and
* can be calibrated using the '-c' option in the sleep command. Even
* with this calibration the accuracy of this mechanism is limited;
* however, since there is no code in the monitor that really requires
* extremely accurate timing this may be ok.
*
* On the other hand, it is preferrable to have accuracy, so on targets
* that have a pollable clock, the hooks can be put in place to allow
* that clock to be used as the hardware assist for the monitor's
* elapsed time measurements. The INCLUDE_HWTMR is set to 1, and
* TIMER_TICKS_PER_MSEC defines the number of ticks of the timer that
* correspond to 1 millisecond of elapsed time. The function target_timer()
* is assumed to be established and must return an unsigned long value
* that is the content of the polled hardware timer.
*
* Regardless of the hardware-assist or not, the following interface is
* used by the code in the monitor...
*
* #include "timer.h"
*
* struct elapsed_tmr tmr;
*
* startElapsedTimer(&tmr,TIMEOUT):
* do {
* SOMETHING();
* } while(!msecElapsed(&tmr));
*
* Refer to the functions startElapsedTimer() and msecElapsed() below for
* more details.
*
* Original author: Ed Sutter (ed.sutter@alcatel-lucent.com)
*
*/
#include "config.h"
#include "stddefs.h"
#include "cli.h"
#include "genlib.h"
#include "ether.h"
#include "timer.h"
#include "cpuio.h"
/* startElapsedTimer() & msecElapsed():
* The timer is started by loading the values timeout_low and timeout_high
* with the number of ticks that must elapse for the timer to expire.
*
* In the case of the non-hardware-assisted timer, the expiration count
* is based on the value of LoopsPerMillisecond (derived from the
* LOOPS_PER_SECOND definition in config.h). Each time msecElapsed()
* is called the elapsed count is incremented until it exceeds the timeout
* timeout_low timeout_high values recorded by startElapsedTimer().
*
* The case of the hardware-assisted timer is similar except that now
* the number of ticks initialized in timeout_low and timeout_high are
* based on the tick rate of the hardware timer (TIMER_TICKS_PER_MSEC).
* This value is expected to be set in config.h. Each time msecElapsed()
* is called, it samples the timer and adds to the running total of ticks
* until it matches or exceeds the timeout_low and timeout_high values.
*
* Notice that 64-bit values are used (high & low) because a 32-bit value
* isn't large enough to deal with the tick rates (per second) of various
* CPUs.
*/
void
startElapsedTimer(struct elapsed_tmr *tmr, long milliseconds)
{
unsigned long new_tm_low;
unsigned long stepmsecs, stepticks, remainder;
#if INCLUDE_HWTMR
tmr->tmrflags = HWTMR_ENABLED;
tmr->tpm = (unsigned long)TIMER_TICKS_PER_MSEC;
#else
tmr->tmrflags = 0;
tmr->tpm = (unsigned long)LoopsPerMillisecond;
#endif
tmr->elapsed_low = 0;
tmr->elapsed_high = 0;
tmr->timeout_high = 0;
tmr->timeout_low = 0;
/* Convert incoming timeout from a millisecond count to a
* tick count...
* Maximum number of milliseconds and ticks before 32-bit
* (tick counter) unsigned long overlaps
*/
stepmsecs = 0xffffffff / tmr->tpm;
stepticks = stepmsecs * tmr->tpm;
remainder = (milliseconds % stepmsecs);
/* Take care of the step remainder
*/
tmr->timeout_low = remainder * tmr->tpm;
milliseconds -= remainder;
for (;milliseconds; milliseconds -= stepmsecs) {
new_tm_low = tmr->timeout_low + stepticks;
if (new_tm_low < tmr->timeout_low)
tmr->timeout_high++;
tmr->timeout_low = new_tm_low;
}
#if INCLUDE_HWTMR
tmr->tmrval = target_timer();
#else
tmr->tmrval = 0;
#endif
}
int
msecElapsed(struct elapsed_tmr *tmr)
{
ulong new_elapsed_low, new_tmrval, elapsed;
/* If timeout has already occurred, then we can assume that this
* function being called without a matching startElapsedTimer() call.
*/
if (ELAPSED_TIMEOUT(tmr))
return(1);
#if INCLUDE_HWTMR
new_tmrval = target_timer();
#else
new_tmrval = tmr->tmrval + 1;
#endif
/* Record how many ticks elapsed since the last call to msecElapsed
* and add that value to the total number of ticks that have elapsed.
*/
elapsed = new_tmrval - tmr->tmrval;
new_elapsed_low = tmr->elapsed_low + elapsed;
if (new_elapsed_low < tmr->elapsed_low)
tmr->elapsed_high++;
/* If the total elapsed number of ticks exceeds the timeout number
* of ticks, then we can return 1 to indicate that the requested
* amount of time has elapsed. Otherwise, we record the values and
* return 0.
*/
if ((tmr->elapsed_high >= tmr->timeout_high) &&
(new_elapsed_low >= tmr->timeout_low)) {
tmr->tmrflags |= TIMEOUT_OCCURRED;
return(1);
}
tmr->tmrval = new_tmrval;
tmr->elapsed_low = new_elapsed_low;
return(0);
}
/* msecRemainging():
* Used to query how many milliseconds were left (if any) in the timeout.
*/
ulong
msecRemaining(struct elapsed_tmr *tmr)
{
ulong high, low, msectot, leftover, divisor;
if (ELAPSED_TIMEOUT(tmr))
return(0);
high = tmr->timeout_high - tmr->elapsed_high;
low = tmr->timeout_low - tmr->elapsed_low;
msectot = leftover = 0;
#if INCLUDE_HWTMR
divisor = (ulong)TIMER_TICKS_PER_MSEC;
#else
divisor = (ulong)LoopsPerMillisecond;
#endif
while(1) {
while (low > divisor) {
msectot++;
low -= divisor;
}
leftover += low;
if (high == 0)
break;
else {
high--;
low = 0xffffffff;
}
}
while(leftover > divisor) {
msectot++;
low -= divisor;
}
return(msectot);
}
/* monDelay():
* Delay for specified number of milliseconds.
* Refer to msecElapsed() description for a discussion on the
* accuracy of this delay.
*/
void
monDelay(int milliseconds)
{
struct elapsed_tmr tmr;
startElapsedTimer(&tmr,milliseconds);
while(!msecElapsed(&tmr)) {
WATCHDOG_MACRO;
pollethernet();
}
}
/* monTimer():
* Provide the API with the ability to start a millisecond-granularity
* timer with some countdown value, and poll it waiting for completion.
*/
int
monTimer(int cmd, void *arg)
{
int rc = 0;
struct elapsed_tmr *tmr = (struct elapsed_tmr *)arg;
switch(cmd) {
case TIMER_START:
startElapsedTimer(tmr,tmr->start);
break;
case TIMER_ELAPSED:
msecElapsed(tmr);
if (ELAPSED_TIMEOUT(tmr))
rc = 1;
break;
case TIMER_QUERY:
#if INCLUDE_HWTMR
tmr->tmrflags = HWTMR_ENABLED;
tmr->tpm = (unsigned long)TIMER_TICKS_PER_MSEC;
tmr->currenttmrval = target_timer();
#else
tmr->tmrflags = 0;
tmr->tpm = (unsigned long)LoopsPerMillisecond;
tmr->currenttmrval = 0;
#endif
break;
default:
rc = -1;
break;
}
return(rc);
}
#if INCLUDE_TFSSCRIPT
/* Sleep():
* Simple delay loop accessible by the command line.
* This loop count is dependent on the underlying hardware.
* The LoopsPerMillisecond count is loaded with a default at startup, or
* it can be calibrated by the user via the -c option.
* Note that this LoopsPerMillisecond value is used in a few other places
* in the monitor also for time-dependent stuff.
* NOTES:
* - This is obviously not real accurate (not intended to be), but allows the
* monitor to be independent of the underlying hardware.
* - The delay time is very dependent on ethernet activity, since the call
* to pollethernet() part of the loop.
*/
char *SleepHelp[] = {
"Second or msec delay (not precise)",
"-[clmv:] {count}",
#if INCLUDE_VERBOSEHELP
" -c calibrate new LPS count",
" -l store LPS count",
" -m millisecond",
" -v {LPSvarname}",
#endif
0,
};
int
Sleep(int argc,char *argv[])
{
int opt, calibrate, count, multiplier;
multiplier = 1000;
calibrate = 0;
while ((opt=getopt(argc,argv,"clmv:")) != -1) {
switch(opt) {
case 'c':
calibrate = 2;
break;
case 'l':
calibrate = 1;
break;
case 'm':
multiplier = 1;
break;
case 'v':
shell_sprintf(optarg,"%d",LoopsPerMillisecond*1000);
return(CMD_SUCCESS);
default:
return(CMD_PARAM_ERROR);
}
}
/* If no args, just print the current LPS value and return... */
if (argc == 1) {
#if INCLUDE_HWTMR
printf("Hardware-based timer, LPS not applicable\n");
#else
printf("Current LPS = %ld\n",LoopsPerMillisecond * 1000);
#endif
return(CMD_SUCCESS);
}
/* For calibration, take in the count on the command line, then use
* it to put out 5 dots dot at the rate of the loop to allow the user
* to adjust it to be about 1 second.
*/
if (calibrate) {
#if INCLUDE_HWTMR
printf("Hardware-based timer, doesn't calibrate\n");
#else
long lps;
if (argc != optind+1)
return(CMD_PARAM_ERROR);
printf("Current LPS: %ld\n",LoopsPerMillisecond * 1000);
lps = strtol(argv[optind],0,0);
LoopsPerMillisecond = lps/1000;
printf("New LPS: %ld%s\n",LoopsPerMillisecond * 1000,
lps % 1000 ? " (truncated by 1000)" : "");
if (calibrate == 2) {
count = 10;
while(count-- > 0) {
monDelay(1000);
putstr(".\007");
}
putchar('\n');
}
#endif
return(CMD_SUCCESS);
}
if (argc == optind)
count = 1;
else
count = strtol(argv[optind],(char **)0,0);
monDelay(count * multiplier);
return(CMD_SUCCESS);
}
#endif
