/**
* @brief Transmits up to @a len characters from @a buf.
*
* This routine is invoked either from task context with disabled interrupts to
* start a new transmission process with exactly one character in case of an
* idle output state or from the interrupt handler to refill the transmitter.
*
* Returns always zero.
*/
ssize_t ns16550_write_support_int(
int minor,
const char *buf,
size_t len
)
{
console_tbl *c = Console_Port_Tbl [minor];
console_data *d = &Console_Port_Data [minor];
NS16550Context *ctx = d->pDeviceContext;
uint32_t port = c->ulCtrlPort1;
setRegister_f set = c->setRegister;
int i = 0;
int out = len > SP_FIFO_SIZE ? SP_FIFO_SIZE : len;
for (i = 0; i < out; ++i) {
set( port, NS16550_TRANSMIT_BUFFER, buf [i]);
}
ctx->transmitFifoChars = out;
if (out > 0) {
ns16550_enable_interrupts( c, NS16550_ENABLE_ALL_INTR);
} else {
ns16550_enable_interrupts( c, NS16550_ENABLE_ALL_INTR_EXCEPT_TX);
}
return 0;
}
int ns16550_open(
int major,
int minor,
void *arg
)
{
rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *) arg;
struct rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
console_tbl *c = Console_Port_Tbl [minor];
console_data *d = &Console_Port_Data [minor];
d->termios_data = tty;
/* Assert DTR */
if (c->pDeviceFlow != &ns16550_flow_DTRCTS) {
ns16550_assert_DTR( minor);
}
/* Set initial baud */
rtems_termios_set_initial_baud( tty, (intptr_t) c->pDeviceParams);
if (c->pDeviceFns->deviceOutputUsesInterrupts) {
ns16550_initialize_interrupts( minor);
ns16550_enable_interrupts( c, NS16550_ENABLE_ALL_INTR_EXCEPT_TX);
}
return RTEMS_SUCCESSFUL;
}
/**
* @brief Process interrupt.
*/
NS16550_STATIC void ns16550_process( int minor)
{
console_tbl *c = Console_Port_Tbl [minor];
console_data *d = &Console_Port_Data [minor];
ns16550_context *ctx = d->pDeviceContext;
uint32_t port = c->ulCtrlPort1;
getRegister_f get = c->getRegister;
int i = 0;
char buf [SP_FIFO_SIZE];
/* Iterate until no more interrupts are pending */
do {
/* Fetch received characters */
for (i = 0; i < SP_FIFO_SIZE; ++i) {
if ((get( port, NS16550_LINE_STATUS) & SP_LSR_RDY) != 0) {
buf [i] = (char) get(port, NS16550_RECEIVE_BUFFER);
} else {
break;
}
}
/* Enqueue fetched characters */
rtems_termios_enqueue_raw_characters( d->termios_data, buf, i);
/* Check if we can dequeue transmitted characters */
if (ctx->transmitFifoChars > 0
&& (get( port, NS16550_LINE_STATUS) & SP_LSR_THOLD) != 0) {
unsigned chars = ctx->transmitFifoChars;
/*
* We finished the transmission, so clear the number of characters in the
* transmit FIFO.
*/
ctx->transmitFifoChars = 0;
/* Dequeue transmitted characters */
if (rtems_termios_dequeue_characters( d->termios_data, chars) == 0) {
/* Nothing to do */
d->bActive = false;
ns16550_enable_interrupts( c, NS16550_ENABLE_ALL_INTR_EXCEPT_TX);
}
}
} while ((get( port, NS16550_INTERRUPT_ID) & SP_IID_0) == 0);
}
/**
* @brief Polled write for NS16550.
*/
void ns16550_outch_polled(console_tbl *c, char out)
{
uintptr_t port = c->ulCtrlPort1;
getRegister_f get = c->getRegister;
setRegister_f set = c->setRegister;
uint32_t status = 0;
rtems_interrupt_lock_context lock_context;
/* Save port interrupt mask */
uint32_t interrupt_mask = get( port, NS16550_INTERRUPT_ENABLE);
/* Disable port interrupts */
ns16550_enable_interrupts( c, NS16550_DISABLE_ALL_INTR);
while (true) {
/* Try to transmit the character in a critical section */
rtems_interrupt_lock_acquire(&ns16550_lock, &lock_context);
/* Read the transmitter holding register and check it */
status = get( port, NS16550_LINE_STATUS);
if ((status & SP_LSR_THOLD) != 0) {
/* Transmit character */
set( port, NS16550_TRANSMIT_BUFFER, out);
/* Finished */
rtems_interrupt_lock_release(&ns16550_lock, &lock_context);
break;
} else {
rtems_interrupt_lock_release(&ns16550_lock, &lock_context);
}
/* Wait for transmitter holding register to be empty */
do {
status = get( port, NS16550_LINE_STATUS);
} while ((status & SP_LSR_THOLD) == 0);
}
/* Restore port interrupt mask */
set( port, NS16550_INTERRUPT_ENABLE, interrupt_mask);
}
int ns16550_close(
int major,
int minor,
void * arg
)
{
console_tbl *c = Console_Port_Tbl [minor];
/*
* Negate DTR
*/
if (c->pDeviceFlow != &ns16550_flow_DTRCTS) {
ns16550_negate_DTR(minor);
}
ns16550_enable_interrupts(c, NS16550_DISABLE_ALL_INTR);
if (c->pDeviceFns->deviceOutputUsesInterrupts) {
ns16550_cleanup_interrupts(minor);
}
return(RTEMS_SUCCESSFUL);
}
void ns16550_init(int minor)
{
uintptr_t pNS16550;
uint8_t ucDataByte;
uint32_t ulBaudDivisor;
NS16550Context *pns16550Context;
setRegister_f setReg;
getRegister_f getReg;
console_tbl *c = Console_Port_Tbl [minor];
pns16550Context=(NS16550Context *)malloc(sizeof(NS16550Context));
if (pns16550Context == NULL) {
printk( "%s: Error: Not enough memory\n", __func__);
rtems_fatal_error_occurred( 0xdeadbeef);
}
Console_Port_Data[minor].pDeviceContext=(void *)pns16550Context;
pns16550Context->ucModemCtrl=SP_MODEM_IRQ;
pNS16550 = c->ulCtrlPort1;
setReg = c->setRegister;
getReg = c->getRegister;
/* Clear the divisor latch, clear all interrupt enables,
* and reset and
* disable the FIFO's.
*/
(*setReg)(pNS16550, NS16550_LINE_CONTROL, 0x0);
ns16550_enable_interrupts( c, NS16550_DISABLE_ALL_INTR );
/* Set the divisor latch and set the baud rate. */
ulBaudDivisor = NS16550_GetBaudDivisor(c, (uintptr_t) c->pDeviceParams);
ucDataByte = SP_LINE_DLAB;
(*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte);
/* XXX */
(*setReg)(pNS16550,NS16550_TRANSMIT_BUFFER,(uint8_t)(ulBaudDivisor & 0xffU));
(*setReg)(
pNS16550,NS16550_INTERRUPT_ENABLE,
(uint8_t)(( ulBaudDivisor >> 8 ) & 0xffU )
);
/* Clear the divisor latch and set the character size to eight bits */
/* with one stop bit and no parity checking. */
ucDataByte = EIGHT_BITS;
(*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte);
/* Enable and reset transmit and receive FIFOs. TJA */
ucDataByte = SP_FIFO_ENABLE;
(*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte);
ucDataByte = SP_FIFO_ENABLE | SP_FIFO_RXRST | SP_FIFO_TXRST;
(*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte);
ns16550_enable_interrupts(c, NS16550_DISABLE_ALL_INTR);
/* Set data terminal ready. */
/* And open interrupt tristate line */
(*setReg)(pNS16550, NS16550_MODEM_CONTROL,pns16550Context->ucModemCtrl);
(*getReg)(pNS16550, NS16550_LINE_STATUS );
(*getReg)(pNS16550, NS16550_RECEIVE_BUFFER );
}
