static void jsm_tty_start_tx(struct uart_port *port)
{
struct jsm_channel *channel = (struct jsm_channel *)port;
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");
channel->ch_flags &= ~(CH_STOP);
jsm_tty_write(port);
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
}
static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch)
{
u16 head;
u16 tail;
int n;
int s;
int qlen;
u32 len_written = 0;
if (!ch)
return;
/* No data to write to the UART */
if (ch->ch_w_tail == ch->ch_w_head)
return;
/* If port is "stopped", don't send any data to the UART */
if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
return;
/*
* If FIFOs are disabled. Send data directly to txrx register
*/
if (!(ch->ch_flags & CH_FIFO_ENABLED)) {
u8 lsrbits = readb(&ch->ch_neo_uart->lsr);
ch->ch_cached_lsr |= lsrbits;
if (ch->ch_cached_lsr & UART_LSR_THRE) {
ch->ch_cached_lsr &= ~(UART_LSR_THRE);
writeb(ch->ch_wqueue[ch->ch_w_tail], &ch->ch_neo_uart->txrx);
jsm_printk(WRITE, INFO, &ch->ch_bd->pci_dev,
"Tx data: %x\n", ch->ch_wqueue[ch->ch_w_head]);
ch->ch_w_tail++;
ch->ch_w_tail &= WQUEUEMASK;
ch->ch_txcount++;
}
return;
}
/*
* We have to do it this way, because of the EXAR TXFIFO count bug.
*/
if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
return;
n = UART_17158_TX_FIFOSIZE - ch->ch_t_tlevel;
/* cache head and tail of queue */
head = ch->ch_w_head & WQUEUEMASK;
tail = ch->ch_w_tail & WQUEUEMASK;
qlen = (head - tail) & WQUEUEMASK;
/* Find minimum of the FIFO space, versus queue length */
n = min(n, qlen);
while (n > 0) {
s = ((head >= tail) ? head : WQUEUESIZE) - tail;
s = min(s, n);
if (s <= 0)
break;
memcpy_toio(&ch->ch_neo_uart->txrxburst, ch->ch_wqueue + tail, s);
/* Add and flip queue if needed */
tail = (tail + s) & WQUEUEMASK;
n -= s;
ch->ch_txcount += s;
len_written += s;
}
/* Update the final tail */
ch->ch_w_tail = tail & WQUEUEMASK;
if (len_written >= ch->ch_t_tlevel)
ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
if (!jsm_tty_write(&ch->uart_port))
uart_write_wakeup(&ch->uart_port);
}
