int main(void)
{
/* This is a fairly solid assumption that the math we're doing
* is based on tb_hz of exactly 512mhz.
* If we do start doing the math on different tb_hz, you probably
* want to go and audit every bit of code that touches tb to
* count/delay things.
*/
assert(tb_hz == 512000000);
assert(secs_to_tb(1) == tb_hz);
assert(secs_to_tb(2) == 1024000000);
assert(secs_to_tb(10) == 5120000000);
assert(tb_to_secs(512000000) == 1);
assert(tb_to_secs(5120000000) == 10);
assert(tb_to_secs(1024000000) == 2);
assert(msecs_to_tb(1) == 512000);
assert(msecs_to_tb(100) == 51200000);
assert(msecs_to_tb(5) == 2560000);
assert(tb_to_msecs(512000) == 1);
assert(usecs_to_tb(5) == 2560);
assert(tb_to_usecs(2560) == 5);
assert(usecs_to_tb(5)*1000 == msecs_to_tb(5));
assert(tb_to_usecs(512000) == 1000);
assert(tb_compare(msecs_to_tb(5), usecs_to_tb(5)) == TB_AAFTERB);
assert(tb_compare(msecs_to_tb(5), usecs_to_tb(50000)) == TB_ABEFOREB);
assert(tb_compare(msecs_to_tb(5), usecs_to_tb(5)*1000) == TB_AEQUALB);
return 0;
}
/* This is called with the timer lock held, so there is no
* issue with re-entrancy or concurrence
*/
void p8_sbe_update_timer_expiry(uint64_t new_target)
{
uint64_t count, gen, gen2, req, now;
int64_t rc;
if (!sbe_has_timer || new_target == sbe_timer_target)
return;
sbe_timer_target = new_target;
_xscom_lock();
now = mftb();
/* Calculate how many increments from now, rounded up */
if (now < new_target)
count = (new_target - now + sbe_timer_inc - 1) / sbe_timer_inc;
else
count = 1;
/* Max counter is 24-bit */
if (count > 0xffffff)
count = 0xffffff;
/* Fabricate update request */
req = (1ull << 63) | (count << 32);
prlog(PR_TRACE, "SLW: TMR expiry: 0x%llx, req: %016llx\n", count, req);
do {
/* Grab generation and spin if odd */
for (;;) {
rc = _xscom_read(sbe_timer_chip, 0xE0006, &gen, false);
if (rc) {
prerror("SLW: Error %lld reading tmr gen "
" count\n", rc);
_xscom_unlock();
return;
}
if (!(gen & 1))
break;
if (tb_compare(now + msecs_to_tb(1), mftb()) == TB_ABEFOREB) {
/**
* @fwts-label SLWTimerStuck
* @fwts-advice The SLeep/Winkle Engine (SLW)
* failed to increment the generation number
* within our timeout period (it *should* have
* done so within ~10us, not >1ms. OPAL uses
* the SLW timer to schedule some operations,
* but can fall back to the (much less frequent
* OPAL poller, which although does not affect
* functionality, runs *much* less frequently.
* This could have the effect of slow I2C
* operations (for example). It may also mean
* that you *had* an increase in jitter, due
* to slow interactions with SLW.
* This error may also occur if the machine
* is connected to via soft FSI.
*/
prerror("SLW: timer stuck, falling back to OPAL pollers. You will likely have slower I2C and may have experienced increased jitter.\n");
prlog(PR_DEBUG, "SLW: Stuck with odd generation !\n");
_xscom_unlock();
sbe_has_timer = false;
p8_sbe_dump_timer_ffdc();
return;
}
}
rc = _xscom_write(sbe_timer_chip, 0x5003A, req, false);
if (rc) {
prerror("SLW: Error %lld writing tmr request\n", rc);
_xscom_unlock();
return;
}
/* Re-check gen count */
rc = _xscom_read(sbe_timer_chip, 0xE0006, &gen2, false);
if (rc) {
prerror("SLW: Error %lld re-reading tmr gen "
" count\n", rc);
_xscom_unlock();
return;
}
} while(gen != gen2);
_xscom_unlock();
/* Check if the timer is working. If at least 1ms has elapsed
* since the last call to this function, check that the gen
* count has changed
*/
if (tb_compare(sbe_last_gen_stamp + msecs_to_tb(1), now)
== TB_ABEFOREB) {
if (sbe_last_gen == gen) {
prlog(PR_ERR,
"SLW: Timer appears to not be running !\n");
sbe_has_timer = false;
p8_sbe_dump_timer_ffdc();
}
sbe_last_gen = gen;
sbe_last_gen_stamp = mftb();
}
prlog(PR_TRACE, "SLW: gen: %llx\n", gen);
}