/*
* Flush the WRITE FIFO on the Neo.
*
* NOTE: Channel lock MUST be held before calling this function!
*/
static void neo_flush_uart_write(struct jsm_channel *ch)
{
u8 tmp = 0;
int i = 0;
if (!ch)
return;
writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
for (i = 0; i < 10; i++) {
/* Check to see if the UART feels it completely flushed the FIFO. */
tmp = readb(&ch->ch_neo_uart->isr_fcr);
if (tmp & 4) {
jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
"Still flushing TX UART... i: %d\n", i);
udelay(10);
}
else
break;
}
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
}
static void neo_set_cts_flow_control(struct jsm_channel *ch)
{
u8 ier, efr;
ier = readb(&ch->ch_neo_uart->ier);
efr = readb(&ch->ch_neo_uart->efr);
jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting CTSFLOW\n");
/* Turn on auto CTS flow control */
ier |= (UART_17158_IER_CTSDSR);
efr |= (UART_17158_EFR_ECB | UART_17158_EFR_CTSDSR);
/* Turn off auto Xon flow control */
efr &= ~(UART_17158_EFR_IXON);
/* Why? Becuz Exar's spec says we have to zero it out before setting it */
writeb(0, &ch->ch_neo_uart->efr);
/* Turn on UART enhanced bits */
writeb(efr, &ch->ch_neo_uart->efr);
/* Turn on table D, with 8 char hi/low watermarks */
writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
/* Feed the UART our trigger levels */
writeb(8, &ch->ch_neo_uart->tfifo);
ch->ch_t_tlevel = 8;
writeb(ier, &ch->ch_neo_uart->ier);
}
static void neo_parse_modem(struct jsm_channel *ch, u8 signals)
{
u8 msignals = signals;
jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
"neo_parse_modem: port: %d msignals: %x\n",
ch->ch_portnum, msignals);
/* Scrub off lower bits. They signify delta's, which I don't care about */
/* Keep DDCD and DDSR though */
msignals &= 0xf8;
if (msignals & UART_MSR_DDCD)
uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
if (msignals & UART_MSR_DDSR)
uart_handle_cts_change(&ch->uart_port, msignals & UART_MSR_CTS);
if (msignals & UART_MSR_DCD)
ch->ch_mistat |= UART_MSR_DCD;
else
ch->ch_mistat &= ~UART_MSR_DCD;
if (msignals & UART_MSR_DSR)
ch->ch_mistat |= UART_MSR_DSR;
else
ch->ch_mistat &= ~UART_MSR_DSR;
if (msignals & UART_MSR_RI)
ch->ch_mistat |= UART_MSR_RI;
else
ch->ch_mistat &= ~UART_MSR_RI;
if (msignals & UART_MSR_CTS)
ch->ch_mistat |= UART_MSR_CTS;
else
ch->ch_mistat &= ~UART_MSR_CTS;
jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
"Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
ch->ch_portnum,
!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
}
static inline void neo_set_new_start_stop_chars(struct jsm_channel *ch)
{
/* if hardware flow control is set, then skip this whole thing */
if (ch->ch_c_cflag & CRTSCTS)
return;
jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "start\n");
/* Tell UART what start/stop chars it should be looking for */
writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
writeb(0, &ch->ch_neo_uart->xonchar2);
writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
wr
/*
* No locks are assumed to be held when calling this function.
*/
static void neo_clear_break(struct jsm_channel *ch, int force)
{
unsigned long lock_flags;
spin_lock_irqsave(&ch->ch_lock, lock_flags);
/* Turn break off, and unset some variables */
if (ch->ch_flags & CH_BREAK_SENDING) {
u8 temp = readb(&ch->ch_neo_uart->lcr);
writeb((temp & ~UART_LCR_SBC), &ch->ch_neo_uart->lcr);
ch->ch_flags &= ~(CH_BREAK_SENDING);
jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
"clear break Finishing UART_LCR_SBC! finished: %lx\n",
jiffies);
/* flush write operation */
neo_pci_posting_flush(ch->ch_bd);
}
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
}
static void neo_set_rts_flow_control(struct jsm_channel *ch)
{
u8 ier, efr;
ier = readb(&ch->ch_neo_uart->ier);
efr = readb(&ch->ch_neo_uart->efr);
jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting RTSFLOW\n");
/* Turn on auto RTS flow control */
ier |= (UART_17158_IER_RTSDTR);
efr |= (UART_17158_EFR_ECB | UART_17158_EFR_RTSDTR);
/* Turn off auto Xoff flow control */
ier &= ~(UART_17158_IER_XOFF);
efr &= ~(UART_17158_EFR_IXOFF);
/* Why? Becuz Exar's spec says we have to zero it out before setting it */
writeb(0, &ch->ch_neo_uart->efr);
/* Turn on UART enhanced bits */
writeb(efr, &ch->ch_neo_uart->efr);
writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
ch->ch_r_watermark = 4;
writeb(56, &ch->ch_neo_uart->rfifo);
ch->ch_r_tlevel = 56;
writeb(ier, &ch->ch_neo_uart->ier);
/*
* From the Neo UART spec sheet:
* The auto RTS/DTR function must be started by asserting
* RTS/DTR# output pin (MCR bit-0 or 1 to logic 1 after
* it is enabled.
*/
ch->ch_mostat |= (UART_MCR_RTS);
}
static void neo_set_no_input_flow_control(struct jsm_channel *ch)
{
u8 ier, efr;
ier = readb(&ch->ch_neo_uart->ier);
efr = readb(&ch->ch_neo_uart->efr);
jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Input FLOW\n");
/* Turn off auto RTS flow control */
ier &= ~(UART_17158_IER_RTSDTR);
efr &= ~(UART_17158_EFR_RTSDTR);
/* Turn off auto Xoff flow control */
ier &= ~(UART_17158_IER_XOFF);
if (ch->ch_c_iflag & IXON)
efr &= ~(UART_17158_EFR_IXOFF);
else
efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
/* Why? Becuz Exar's spec says we have to zero it out before setting it */
writeb(0, &ch->ch_neo_uart->efr);
/* Turn on UART enhanced bits */
writeb(efr, &ch->ch_neo_uart->efr);
/* Turn on table D, with 8 char hi/low watermarks */
writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
ch->ch_r_watermark = 0;
writeb(16, &ch->ch_neo_uart->tfifo);
ch->ch_t_tlevel = 16;
writeb(16, &ch->ch_neo_uart->rfifo);
ch->ch_r_tlevel = 16;
writeb(ier, &ch->ch_neo_uart->ier);
}
static void neo_set_ixoff_flow_control(struct jsm_channel *ch)
{
u8 ier, efr;
ier = readb(&ch->ch_neo_uart->ier);
efr = readb(&ch->ch_neo_uart->efr);
jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXOFF FLOW\n");
/* Turn off auto RTS flow control */
ier &= ~(UART_17158_IER_RTSDTR);
efr &= ~(UART_17158_EFR_RTSDTR);
/* Turn on auto Xoff flow control */
ier |= (UART_17158_IER_XOFF);
efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
/* Why? Becuz Exar's spec says we have to zero it out before setting it */
writeb(0, &ch->ch_neo_uart->efr);
/* Turn on UART enhanced bits */
writeb(efr, &ch->ch_neo_uart->efr);
/* Turn on table D, with 8 char hi/low watermarks */
writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
writeb(8, &ch->ch_neo_uart->tfifo);
ch->ch_t_tlevel = 8;
/* Tell UART what start/stop chars it should be looking for */
writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
writeb(0, &ch->ch_neo_uart->xonchar2);
writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
writeb(0, &ch->ch_neo_uart->xoffchar2);
writeb(ier, &ch->ch_neo_uart->ier);
}
static inline void neo_parse_lsr(struct jsm_board *brd, u32 port)
{
struct jsm_channel *ch;
int linestatus;
unsigned long lock_flags;
if (!brd)
return;
if (port > brd->maxports)
return;
ch = brd->channels[port];
if (!ch)
return;
linestatus = readb(&ch->ch_neo_uart->lsr);
jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d port: %d linestatus: %x\n",
__FILE__, __LINE__, port, linestatus);
ch->ch_cached_lsr |= linestatus;
if (ch->ch_cached_lsr & UART_LSR_DR) {
/* Read data from uart -> queue */
neo_copy_data_from_uart_to_queue(ch);
spin_lock_irqsave(&ch->ch_lock, lock_flags);
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
}
/*
* This is a special flag. It indicates that at least 1
* RX error (parity, framing, or break) has happened.
* Mark this in our struct, which will tell me that I have
*to do the special RX+LSR read for this FIFO load.
*/
if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"%s:%d Port: %d Got an RX error, need to parse LSR\n",
__FILE__, __LINE__, port);
/*
* The next 3 tests should *NOT* happen, as the above test
* should encapsulate all 3... At least, thats what Exar says.
*/
if (linestatus & UART_LSR_PE) {
ch->ch_err_parity++;
jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. PAR ERR!\n",
__FILE__, __LINE__, port);
}
if (linestatus & UART_LSR_FE) {
ch->ch_err_frame++;
jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. FRM ERR!\n",
__FILE__, __LINE__, port);
}
if (linestatus & UART_LSR_BI) {
ch->ch_err_break++;
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"%s:%d Port: %d. BRK INTR!\n",
__FILE__, __LINE__, port);
}
if (linestatus & UART_LSR_OE) {
/*
* Rx Oruns. Exar says that an orun will NOT corrupt
* the FIFO. It will just replace the holding register
* with this new data byte. So basically just ignore this.
* Probably we should eventually have an orun stat in our driver...
*/
ch->ch_err_overrun++;
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"%s:%d Port: %d. Rx Overrun!\n",
__FILE__, __LINE__, port);
}
if (linestatus & UART_LSR_THRE) {
spin_lock_irqsave(&ch->ch_lock, lock_flags);
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
/* Transfer data (if any) from Write Queue -> UART. */
neo_copy_data_from_queue_to_uart(ch);
}
else if (linestatus & UART_17158_TX_AND_FIFO_CLR) {
spin_lock_irqsave(&ch->ch_lock, lock_flags);
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
/* Transfer data (if any) from Write Queue -> UART. */
neo_copy_data_from_queue_to_uart(ch);
}
}
/*
* Parse the ISR register.
*/
static inline void neo_parse_isr(struct jsm_board *brd, u32 port)
{
struct jsm_channel *ch;
u8 isr;
u8 cause;
unsigned long lock_flags;
if (!brd)
return;
if (port > brd->maxports)
return;
ch = brd->channels[port];
if (!ch)
return;
/* Here we try to figure out what caused the interrupt to happen */
while (1) {
isr = readb(&ch->ch_neo_uart->isr_fcr);
/* Bail if no pending interrupt */
if (isr & UART_IIR_NO_INT)
break;
/*
* Yank off the upper 2 bits, which just show that the FIFO's are enabled.
*/
isr &= ~(UART_17158_IIR_FIFO_ENABLED);
jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d isr: %x\n",
__FILE__, __LINE__, isr);
if (isr & (UART_17158_IIR_RDI_TIMEOUT | UART_IIR_RDI)) {
/* Read data from uart -> queue */
neo_copy_data_from_uart_to_queue(ch);
/* Call our tty layer to enforce queue flow control if needed. */
spin_lock_irqsave(&ch->ch_lock, lock_flags);
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
}
if (isr & UART_IIR_THRI) {
/* Transfer data (if any) from Write Queue -> UART. */
spin_lock_irqsave(&ch->ch_lock, lock_flags);
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
neo_copy_data_from_queue_to_uart(ch);
}
if (isr & UART_17158_IIR_XONXOFF) {
cause = readb(&ch->ch_neo_uart->xoffchar1);
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"Port %d. Got ISR_XONXOFF: cause:%x\n",
port, cause);
/*
* Since the UART detected either an XON or
* XOFF match, we need to figure out which
* one it was, so we can suspend or resume data flow.
*/
spin_lock_irqsave(&ch->ch_lock, lock_flags);
if (cause == UART_17158_XON_DETECT) {
/* Is output stopped right now, if so, resume it */
if (brd->channels[port]->ch_flags & CH_STOP) {
ch->ch_flags &= ~(CH_STOP);
}
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"Port %d. XON detected in incoming data\n",
port);
}
else if (cause == UART_17158_XOFF_DETECT) {
if (!(brd->channels[port]->ch_flags & CH_STOP)) {
ch->ch_flags |= CH_STOP;
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"Setting CH_STOP\n");
}
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"Port: %d. XOFF detected in incoming data\n",
port);
}
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
}
if (isr & UART_17158_IIR_HWFLOW_STATE_CHANGE) {
/*
* If we get here, this means the hardware is doing auto flow control.
* Check to see whether RTS/DTR or CTS/DSR caused this interrupt.
*/
cause = readb(&ch->ch_neo_uart->mcr);
/* Which pin is doing auto flow? RTS or DTR? */
spin_lock_irqsave(&ch->ch_lock, lock_flags);
if ((cause & 0x4) == 0) {
if (cause & UART_MCR_RTS)
ch->ch_mostat |= UART_MCR_RTS;
else
ch->ch_mostat &= ~(UART_MCR_RTS);
} else {
if (cause & UART_MCR_DTR)
ch->ch_mostat |= UART_MCR_DTR;
else
ch->ch_mostat &= ~(UART_MCR_DTR);
}
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
}
/* Parse any modem signal changes */
jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"MOD_STAT: sending to parse_modem_sigs\n");
neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
}
}
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;
struct circ_buf *circ;
if (!ch)
return;
circ = &ch->uart_port.state->xmit;
/* No data to write to the UART */
if (uart_circ_empty(circ))
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(circ->buf[circ->tail], &ch->ch_neo_uart->txrx);
jsm_dbg(WRITE, &ch->ch_bd->pci_dev,
"Tx data: %x\n", circ->buf[circ->tail]);
circ->tail = (circ->tail + 1) & (UART_XMIT_SIZE - 1);
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 = circ->head & (UART_XMIT_SIZE - 1);
tail = circ->tail & (UART_XMIT_SIZE - 1);
qlen = uart_circ_chars_pending(circ);
/* Find minimum of the FIFO space, versus queue length */
n = min(n, qlen);
while (n > 0) {
s = ((head >= tail) ? head : UART_XMIT_SIZE) - tail;
s = min(s, n);
if (s <= 0)
break;
memcpy_toio(&ch->ch_neo_uart->txrxburst, circ->buf + tail, s);
/* Add and flip queue if needed */
tail = (tail + s) & (UART_XMIT_SIZE - 1);
n -= s;
ch->ch_txcount += s;
len_written += s;
}
/* Update the final tail */
circ->tail = tail & (UART_XMIT_SIZE - 1);
if (len_written >= ch->ch_t_tlevel)
ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
if (uart_circ_empty(circ))
uart_write_wakeup(&ch->uart_port);
}
static void neo_copy_data_from_uart_to_queue(struct jsm_channel *ch)
{
int qleft = 0;
u8 linestatus = 0;
u8 error_mask = 0;
int n = 0;
int total = 0;
u16 head;
u16 tail;
if (!ch)
return;
/* cache head and tail of queue */
head = ch->ch_r_head & RQUEUEMASK;
tail = ch->ch_r_tail & RQUEUEMASK;
/* Get our cached LSR */
linestatus = ch->ch_cached_lsr;
ch->ch_cached_lsr = 0;
/* Store how much space we have left in the queue */
if ((qleft = tail - head - 1) < 0)
qleft += RQUEUEMASK + 1;
/*
* If the UART is not in FIFO mode, force the FIFO copy to
* NOT be run, by setting total to 0.
*
* On the other hand, if the UART IS in FIFO mode, then ask
* the UART to give us an approximation of data it has RX'ed.
*/
if (!(ch->ch_flags & CH_FIFO_ENABLED))
total = 0;
else {
total = readb(&ch->ch_neo_uart->rfifo);
/*
* EXAR chip bug - RX FIFO COUNT - Fudge factor.
*
* This resolves a problem/bug with the Exar chip that sometimes
* returns a bogus value in the rfifo register.
* The count can be any where from 0-3 bytes "off".
* Bizarre, but true.
*/
total -= 3;
}
/*
* Finally, bound the copy to make sure we don't overflow
* our own queue...
* The byte by byte copy loop below this loop this will
* deal with the queue overflow possibility.
*/
total = min(total, qleft);
while (total > 0) {
/*
* Grab the linestatus register, we need to check
* to see if there are any errors in the FIFO.
*/
linestatus = readb(&ch->ch_neo_uart->lsr);
/*
* Break out if there is a FIFO error somewhere.
* This will allow us to go byte by byte down below,
* finding the exact location of the error.
*/
if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
break;
/* Make sure we don't go over the end of our queue */
n = min(((u32) total), (RQUEUESIZE - (u32) head));
/*
* Cut down n even further if needed, this is to fix
* a problem with memcpy_fromio() with the Neo on the
* IBM pSeries platform.
* 15 bytes max appears to be the magic number.
*/
n = min((u32) n, (u32) 12);
/*
* Since we are grabbing the linestatus register, which
* will reset some bits after our read, we need to ensure
* we don't miss our TX FIFO emptys.
*/
if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR))
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
linestatus = 0;
/* Copy data from uart to the queue */
memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, n);
/*
* Since RX_FIFO_DATA_ERROR was 0, we are guaranteed
* that all the data currently in the FIFO is free of
* breaks and parity/frame/orun errors.
*/
memset(ch->ch_equeue + head, 0, n);
/* Add to and flip head if needed */
head = (head + n) & RQUEUEMASK;
total -= n;
qleft -= n;
ch->ch_rxcount += n;
}
/*
* Create a mask to determine whether we should
* insert the character (if any) into our queue.
*/
if (ch->ch_c_iflag & IGNBRK)
error_mask |= UART_LSR_BI;
/*
* Now cleanup any leftover bytes still in the UART.
* Also deal with any possible queue overflow here as well.
*/
while (1) {
/*
* Its possible we have a linestatus from the loop above
* this, so we "OR" on any extra bits.
*/
linestatus |= readb(&ch->ch_neo_uart->lsr);
/*
* If the chip tells us there is no more data pending to
* be read, we can then leave.
* But before we do, cache the linestatus, just in case.
*/
if (!(linestatus & UART_LSR_DR)) {
ch->ch_cached_lsr = linestatus;
break;
}
/* No need to store this bit */
linestatus &= ~UART_LSR_DR;
/*
* Since we are grabbing the linestatus register, which
* will reset some bits after our read, we need to ensure
* we don't miss our TX FIFO emptys.
*/
if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR)) {
linestatus &= ~(UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR);
ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
}
/*
* Discard character if we are ignoring the error mask.
*/
if (linestatus & error_mask) {
u8 discard;
linestatus = 0;
memcpy_fromio(&discard, &ch->ch_neo_uart->txrxburst, 1);
continue;
}
/*
* If our queue is full, we have no choice but to drop some data.
* The assumption is that HWFLOW or SWFLOW should have stopped
* things way way before we got to this point.
*
* I decided that I wanted to ditch the oldest data first,
* I hope thats okay with everyone? Yes? Good.
*/
while (qleft < 1) {
jsm_dbg(READ, &ch->ch_bd->pci_dev,
"Queue full, dropping DATA:%x LSR:%x\n",
ch->ch_rqueue[tail], ch->ch_equeue[tail]);
ch->ch_r_tail = tail = (tail + 1) & RQUEUEMASK;
ch->ch_err_overrun++;
qleft++;
}
memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, 1);
ch->ch_equeue[head] = (u8) linestatus;
jsm_dbg(READ, &ch->ch_bd->pci_dev, "DATA/LSR pair: %x %x\n",
ch->ch_rqueue[head], ch->ch_equeue[head]);
/* Ditch any remaining linestatus value. */
linestatus = 0;
/* Add to and flip head if needed */
head = (head + 1) & RQUEUEMASK;
qleft--;
ch->ch_rxcount++;
}
/*
* Write new final heads to channel structure.
*/
ch->ch_r_head = head & RQUEUEMASK;
ch->ch_e_head = head & EQUEUEMASK;
jsm_input(ch);
}