/*
* Nudge the transmitter...
*
* XXX: I inherited some funny code here. It implies the host card only
* interrupts when the transmit buffer reaches the low-water-mark, and does
* not interrupt when it's actually hits empty. In some cases, we have
* processes waiting for complete drain, and we need to simulate an interrupt
* about when we think the buffer is going to be empty (and retry if not).
* I really am not certain about this... I *need* the hardware manuals.
*/
static void
si_start(struct tty *tp)
{
struct si_port *pp;
volatile struct si_channel *ccbp;
BYTE ipos, count;
#if 0
int nchar;
#endif
int oldspl, n, amount;
oldspl = spltty();
mtx_assert(&Giant, MA_OWNED);
pp = tty_softc(tp);
DPRINT((pp, DBG_ENTRY|DBG_START,
"si_start(%x) sp_state %x\n",
tp, pp->sp_state));
ccbp = pp->sp_ccb;
while ((count = (int)ccbp->hi_txipos - (int)ccbp->hi_txopos) < 255) {
DPRINT((pp, DBG_START, "txbuf pend count %d\n", (BYTE)count));
ipos = (unsigned int)ccbp->hi_txipos;
if ((int)ccbp->hi_txopos <= ipos)
amount = SI_BUFFERSIZE - ipos;
else
amount = 255 - count;
DPRINT((pp, DBG_START, "spaceleft amount %d\n", amount));
if (amount == 0)
break;
n = ttydisc_getc(tp, si_txbuf, amount);
DPRINT((pp, DBG_START, "getc n=%d\n", n));
if (n == 0)
break;
si_bcopyv(si_txbuf, &ccbp->hi_txbuf[ipos], n);
ccbp->hi_txipos += n;
}
#if 0
/*
* See if there are any characters still to come. If so, we can
* depend on si_start being called again.
*
* XXX the manual is vague on this. It implies we get an interrupt
* when the transmit queue reaches the 25% low water mark, but NOT
* when it hits empty.
*/
nchar = ttyoutq_getsize(&tp->t_outq) - ttyoutq_bytesleft(&tp->t_outq);
DPRINT((pp, DBG_START, "count %d, nchar %d\n",
(BYTE)count, nchar));
if (count != 0 && nchar == 0) {
int time;
/* XXX lame. Ticks per character. used to be a table. */
time = (tp->t_termios.c_ospeed + 9) / 10;
if (time > 0) {
if (time < nchar)
time = nchar / time;
else
time = 2;
} else {
DPRINT((pp, DBG_START,
"bad char time value! %d\n", time));
time = hz/10;
}
if ((pp->sp_state & SS_LSTART) != 0)
untimeout(si_lstart, (caddr_t)pp, pp->lstart_ch);
DPRINT((pp, DBG_START, "arming lstart, time=%d\n", time));
pp->sp_state |= SS_LSTART;
pp->lstart_ch = timeout(si_lstart, (caddr_t)pp, time);
}
#endif
splx(oldspl);
DPRINT((pp, DBG_EXIT|DBG_START, "leave si_start()\n"));
}
/*
* Nudge the transmitter...
*
* XXX: I inherited some funny code here. It implies the host card only
* interrupts when the transmit buffer reaches the low-water-mark, and does
* not interrupt when it's actually hits empty. In some cases, we have
* processes waiting for complete drain, and we need to simulate an interrupt
* about when we think the buffer is going to be empty (and retry if not).
* I really am not certain about this... I *need* the hardware manuals.
*/
static void
si_start(struct tty *tp)
{
struct si_port *pp;
volatile struct si_channel *ccbp;
struct clist *qp;
BYTE ipos;
int nchar;
int oldspl, count, n, amount, buffer_full;
oldspl = spltty();
qp = &tp->t_outq;
pp = tp->t_sc;
DPRINT((pp, DBG_ENTRY|DBG_START,
"si_start(%x) t_state %x sp_state %x t_outq.c_cc %d\n",
tp, tp->t_state, pp->sp_state, qp->c_cc));
if (tp->t_state & (TS_TIMEOUT|TS_TTSTOP))
goto out;
buffer_full = 0;
ccbp = pp->sp_ccb;
count = (int)ccbp->hi_txipos - (int)ccbp->hi_txopos;
DPRINT((pp, DBG_START, "count %d\n", (BYTE)count));
while ((nchar = qp->c_cc) > 0) {
if ((BYTE)count >= 255) {
buffer_full++;
break;
}
amount = min(nchar, (255 - (BYTE)count));
ipos = (unsigned int)ccbp->hi_txipos;
n = q_to_b(&tp->t_outq, si_txbuf, amount);
/* will it fit in one lump? */
if ((SI_BUFFERSIZE - ipos) >= n) {
si_bcopyv(si_txbuf, &ccbp->hi_txbuf[ipos], n);
} else {
si_bcopyv(si_txbuf, &ccbp->hi_txbuf[ipos],
SI_BUFFERSIZE - ipos);
si_bcopyv(si_txbuf + (SI_BUFFERSIZE - ipos),
&ccbp->hi_txbuf[0], n - (SI_BUFFERSIZE - ipos));
}
ccbp->hi_txipos += n;
count = (int)ccbp->hi_txipos - (int)ccbp->hi_txopos;
}
if (count != 0 && nchar == 0) {
tp->t_state |= TS_BUSY;
} else {
tp->t_state &= ~TS_BUSY;
}
/* wakeup time? */
ttwwakeup(tp);
DPRINT((pp, DBG_START, "count %d, nchar %d, tp->t_state 0x%x\n",
(BYTE)count, nchar, tp->t_state));
if (tp->t_state & TS_BUSY)
{
int time;
time = ttspeedtab(tp->t_ospeed, chartimes);
if (time > 0) {
if (time < nchar)
time = nchar / time;
else
time = 2;
} else {
DPRINT((pp, DBG_START,
"bad char time value! %d\n", time));
time = hz/10;
}
if ((pp->sp_state & (SS_LSTART|SS_INLSTART)) == SS_LSTART) {
untimeout(si_lstart, (caddr_t)pp, pp->lstart_ch);
} else {
pp->sp_state |= SS_LSTART;
}
DPRINT((pp, DBG_START, "arming lstart, time=%d\n", time));
pp->lstart_ch = timeout(si_lstart, (caddr_t)pp, time);
}
out:
splx(oldspl);
DPRINT((pp, DBG_EXIT|DBG_START, "leave si_start()\n"));
}