/*
* Slightly higher-level routines aware of buffering and flow control.
*/
static inline int
aju_writable(struct altera_jtag_uart_softc *sc)
{
return ((aju_control_read(sc) &
ALTERA_JTAG_UART_CONTROL_WSPACE) != 0);
}
static void
aju_ac_callout(void *arg)
{
struct altera_jtag_uart_softc *sc = arg;
struct tty *tp = sc->ajus_ttyp;
uint32_t v;
tty_lock(tp);
AJU_LOCK(sc);
v = aju_control_read(sc);
if (v & ALTERA_JTAG_UART_CONTROL_AC) {
v &= ~ALTERA_JTAG_UART_CONTROL_AC;
aju_control_write(sc, v);
if (*sc->ajus_jtag_presentp == 0) {
*sc->ajus_jtag_missedp = 0;
*sc->ajus_jtag_presentp = 1;
aju_handle_output(sc, tp);
}
} else if (*sc->ajus_jtag_presentp != 0) {
(*sc->ajus_jtag_missedp)++;
if (*sc->ajus_jtag_missedp >= AJU_JTAG_MAXMISS) {
*sc->ajus_jtag_presentp = 0;
aju_handle_output(sc, tp);
}
}
callout_reset(&sc->ajus_ac_callout, AJU_AC_POLLINTERVAL,
aju_ac_callout, sc);
AJU_UNLOCK(sc);
tty_unlock(tp);
}
/*
* Send output to the UART until either there's none left to send, or we run
* out of room and need to await an interrupt so that we can start sending
* again.
*
* XXXRW: It would be nice to query WSPACE at the beginning and write to the
* FIFO in bugger chunks.
*/
static void
aju_handle_output(struct altera_jtag_uart_softc *sc, struct tty *tp)
{
uint32_t v;
uint8_t ch;
tty_lock_assert(tp, MA_OWNED);
AJU_LOCK_ASSERT(sc);
AJU_UNLOCK(sc);
while (ttydisc_getc_poll(tp) != 0) {
AJU_LOCK(sc);
v = aju_control_read(sc);
if ((v & ALTERA_JTAG_UART_CONTROL_WSPACE) != 0) {
AJU_UNLOCK(sc);
if (ttydisc_getc(tp, &ch, sizeof(ch)) != sizeof(ch))
panic("%s: ttydisc_getc", __func__);
AJU_LOCK(sc);
/*
* XXXRW: There is a slight race here in which we test
* for writability, drop the lock, get the character
* from the tty layer, re-acquire the lock, and then
* write. It's possible for other code --
* specifically, the low-level console -- to have
* written in the mean time, which might mean that
* there is no longer space. The BERI memory bus will
* cause this write to block, wedging the processor
* until space is available -- which could be a while
* if JTAG is not attached!
*
* The 'easy' fix is to drop the character if WSPACE
* has become unset. Not sure what the 'hard' fix is.
*/
aju_data_write(sc, ch);
} else {
/*
* If JTAG is not present, then we will drop this
* character instead of perhaps scheduling an
* interrupt to let us know when there is buffer
* space. Otherwise we might get a write interrupt
* later even though we aren't interested in sending
* anymore. Loop to drain TTY-layer buffer.
*/
if (*sc->ajus_jtag_presentp == 0) {
if (ttydisc_getc(tp, &ch, sizeof(ch)) !=
sizeof(ch))
panic("%s: ttydisc_getc 2", __func__);
AJU_UNLOCK(sc);
continue;
}
if (sc->ajus_irq_res != NULL)
aju_intr_writable_enable(sc);
return;
}
AJU_UNLOCK(sc);
}
AJU_LOCK(sc);
aju_intr_writable_disable(sc);
}
static void
aju_intr_disable(struct altera_jtag_uart_softc *sc)
{
uint32_t v;
AJU_LOCK_ASSERT(sc);
v = aju_control_read(sc);
v &= ~(ALTERA_JTAG_UART_CONTROL_RE | ALTERA_JTAG_UART_CONTROL_WE);
aju_control_write(sc, v);
}
static void
aju_intr_writable_disable(struct altera_jtag_uart_softc *sc)
{
uint32_t v;
AJU_LOCK_ASSERT(sc);
atomic_add_int(&aju_intr_writable_disabled, 1);
v = aju_control_read(sc);
v &= ~ALTERA_JTAG_UART_CONTROL_WE;
aju_control_write(sc, v);
}
static void
aju_intr(void *arg)
{
struct altera_jtag_uart_softc *sc = arg;
struct tty *tp = sc->ajus_ttyp;
uint32_t v;
tty_lock(tp);
AJU_LOCK(sc);
v = aju_control_read(sc);
if (v & ALTERA_JTAG_UART_CONTROL_RI)
aju_handle_input(sc, tp);
if (v & ALTERA_JTAG_UART_CONTROL_WI)
aju_handle_output(sc, tp);
AJU_UNLOCK(sc);
tty_unlock(tp);
}
/*
* Send output to the UART until either there's none left to send, or we run
* out of room and need to await an interrupt so that we can start sending
* again.
*
* XXXRW: It would be nice to query WSPACE at the beginning and write to the
* FIFO in bugger chunks.
*/
static void
aju_handle_output(struct altera_jtag_uart_softc *sc, struct tty *tp)
{
uint32_t v;
uint8_t ch;
tty_lock_assert(tp, MA_OWNED);
AJU_LOCK_ASSERT(sc);
AJU_UNLOCK(sc);
while (ttydisc_getc_poll(tp) != 0) {
AJU_LOCK(sc);
v = aju_control_read(sc);
if ((v & ALTERA_JTAG_UART_CONTROL_WSPACE) != 0) {
AJU_UNLOCK(sc);
if (ttydisc_getc(tp, &ch, sizeof(ch)) != sizeof(ch))
panic("%s: ttydisc_getc", __func__);
AJU_LOCK(sc);
aju_data_write(sc, ch);
} else {
/*
* If JTAG is not present, then we will drop this
* character instead of perhaps scheduling an
* interrupt to let us know when there is buffer
* space. Otherwise we might get a write interrupt
* later even though we aren't interested in sending
* anymore. Loop to drain TTY-layer buffer.
*/
if (*sc->ajus_jtag_presentp == 0) {
if (ttydisc_getc(tp, &ch, sizeof(ch)) !=
sizeof(ch))
panic("%s: ttydisc_getc 2", __func__);
AJU_UNLOCK(sc);
continue;
}
if (sc->ajus_irq_res != NULL)
aju_intr_writable_enable(sc);
return;
}
AJU_UNLOCK(sc);
}
AJU_LOCK(sc);
aju_intr_writable_disable(sc);
}
static void
aju_ac_callout(void *arg)
{
struct altera_jtag_uart_softc *sc = arg;
struct tty *tp = sc->ajus_ttyp;
uint32_t v;
tty_lock(tp);
AJU_LOCK(sc);
v = aju_control_read(sc);
if (v & ALTERA_JTAG_UART_CONTROL_AC) {
v &= ~ALTERA_JTAG_UART_CONTROL_AC;
aju_control_write(sc, v);
if (*sc->ajus_jtag_presentp == 0) {
*sc->ajus_jtag_presentp = 1;
atomic_add_int(&aju_jtag_appeared, 1);
aju_handle_output(sc, tp);
}
/* Any hit eliminates all recent misses. */
*sc->ajus_jtag_missedp = 0;
} else if (*sc->ajus_jtag_presentp != 0) {
/*
* If we've exceeded our tolerance for misses, mark JTAG as
* disconnected and drain output. Otherwise, bump the miss
* counter.
*/
if (*sc->ajus_jtag_missedp > AJU_JTAG_MAXMISS) {
*sc->ajus_jtag_presentp = 0;
atomic_add_int(&aju_jtag_vanished, 1);
aju_handle_output(sc, tp);
} else
(*sc->ajus_jtag_missedp)++;
}
callout_reset(&sc->ajus_ac_callout, AJU_AC_POLLINTERVAL,
aju_ac_callout, sc);
AJU_UNLOCK(sc);
tty_unlock(tp);
}
