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OpenCloudOS-Kernel/drivers/serial/jsm/jsm_tty.c

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/************************************************************************
* Copyright 2003 Digi International (www.digi.com)
*
* Copyright (C) 2004 IBM Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 * Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*
* Contact Information:
* Scott H Kilau <Scott_Kilau@digi.com>
* Ananda Venkatarman <mansarov@us.ibm.com>
* Modifications:
* 01/19/06: changed jsm_input routine to use the dynamically allocated
* tty_buffer changes. Contributors: Scott Kilau and Ananda V.
***********************************************************************/
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_reg.h>
#include <linux/delay.h> /* For udelay */
#include <linux/pci.h>
#include "jsm.h"
static void jsm_carrier(struct jsm_channel *ch);
static inline int jsm_get_mstat(struct jsm_channel *ch)
{
unsigned char mstat;
unsigned result;
jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "start\n");
mstat = (ch->ch_mostat | ch->ch_mistat);
result = 0;
if (mstat & UART_MCR_DTR)
result |= TIOCM_DTR;
if (mstat & UART_MCR_RTS)
result |= TIOCM_RTS;
if (mstat & UART_MSR_CTS)
result |= TIOCM_CTS;
if (mstat & UART_MSR_DSR)
result |= TIOCM_DSR;
if (mstat & UART_MSR_RI)
result |= TIOCM_RI;
if (mstat & UART_MSR_DCD)
result |= TIOCM_CD;
jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
return result;
}
static unsigned int jsm_tty_tx_empty(struct uart_port *port)
{
return TIOCSER_TEMT;
}
/*
* Return modem signals to ld.
*/
static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
{
int result;
struct jsm_channel *channel = (struct jsm_channel *)port;
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");
result = jsm_get_mstat(channel);
if (result < 0)
return -ENXIO;
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
return result;
}
/*
* jsm_set_modem_info()
*
* Set modem signals, called by ld.
*/
static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct jsm_channel *channel = (struct jsm_channel *)port;
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");
if (mctrl & TIOCM_RTS)
channel->ch_mostat |= UART_MCR_RTS;
else
channel->ch_mostat &= ~UART_MCR_RTS;
if (mctrl & TIOCM_DTR)
channel->ch_mostat |= UART_MCR_DTR;
else
channel->ch_mostat &= ~UART_MCR_DTR;
channel->ch_bd->bd_ops->assert_modem_signals(channel);
jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
udelay(10);
}
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 jsm_tty_stop_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_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
}
static void jsm_tty_send_xchar(struct uart_port *port, char ch)
{
unsigned long lock_flags;
struct jsm_channel *channel = (struct jsm_channel *)port;
struct ktermios *termios;
spin_lock_irqsave(&port->lock, lock_flags);
termios = port->info->tty->termios;
if (ch == termios->c_cc[VSTART])
channel->ch_bd->bd_ops->send_start_character(channel);
if (ch == termios->c_cc[VSTOP])
channel->ch_bd->bd_ops->send_stop_character(channel);
spin_unlock_irqrestore(&port->lock, lock_flags);
}
static void jsm_tty_stop_rx(struct uart_port *port)
{
struct jsm_channel *channel = (struct jsm_channel *)port;
channel->ch_bd->bd_ops->disable_receiver(channel);
}
static void jsm_tty_break(struct uart_port *port, int break_state)
{
unsigned long lock_flags;
struct jsm_channel *channel = (struct jsm_channel *)port;
spin_lock_irqsave(&port->lock, lock_flags);
if (break_state == -1)
channel->ch_bd->bd_ops->send_break(channel);
else
channel->ch_bd->bd_ops->clear_break(channel, 0);
spin_unlock_irqrestore(&port->lock, lock_flags);
}
static int jsm_tty_open(struct uart_port *port)
{
struct jsm_board *brd;
int rc = 0;
struct jsm_channel *channel = (struct jsm_channel *)port;
struct ktermios *termios;
/* Get board pointer from our array of majors we have allocated */
brd = channel->ch_bd;
/*
* Allocate channel buffers for read/write/error.
* Set flag, so we don't get trounced on.
*/
channel->ch_flags |= (CH_OPENING);
/* Drop locks, as malloc with GFP_KERNEL can sleep */
if (!channel->ch_rqueue) {
channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
if (!channel->ch_rqueue) {
jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
"unable to allocate read queue buf");
return -ENOMEM;
}
}
if (!channel->ch_equeue) {
channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
if (!channel->ch_equeue) {
jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
"unable to allocate error queue buf");
return -ENOMEM;
}
}
if (!channel->ch_wqueue) {
channel->ch_wqueue = kzalloc(WQUEUESIZE, GFP_KERNEL);
if (!channel->ch_wqueue) {
jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
"unable to allocate write queue buf");
return -ENOMEM;
}
}
channel->ch_flags &= ~(CH_OPENING);
/*
* Initialize if neither terminal is open.
*/
jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev,
"jsm_open: initializing channel in open...\n");
/*
* Flush input queues.
*/
channel->ch_r_head = channel->ch_r_tail = 0;
channel->ch_e_head = channel->ch_e_tail = 0;
channel->ch_w_head = channel->ch_w_tail = 0;
brd->bd_ops->flush_uart_write(channel);
brd->bd_ops->flush_uart_read(channel);
channel->ch_flags = 0;
channel->ch_cached_lsr = 0;
channel->ch_stops_sent = 0;
termios = port->info->tty->termios;
channel->ch_c_cflag = termios->c_cflag;
channel->ch_c_iflag = termios->c_iflag;
channel->ch_c_oflag = termios->c_oflag;
channel->ch_c_lflag = termios->c_lflag;
channel->ch_startc = termios->c_cc[VSTART];
channel->ch_stopc = termios->c_cc[VSTOP];
/* Tell UART to init itself */
brd->bd_ops->uart_init(channel);
/*
* Run param in case we changed anything
*/
brd->bd_ops->param(channel);
jsm_carrier(channel);
channel->ch_open_count++;
jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev, "finish\n");
return rc;
}
static void jsm_tty_close(struct uart_port *port)
{
struct jsm_board *bd;
struct ktermios *ts;
struct jsm_channel *channel = (struct jsm_channel *)port;
jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "start\n");
bd = channel->ch_bd;
ts = channel->uart_port.info->tty->termios;
channel->ch_flags &= ~(CH_STOPI);
channel->ch_open_count--;
/*
* If we have HUPCL set, lower DTR and RTS
*/
if (channel->ch_c_cflag & HUPCL) {
jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev,
"Close. HUPCL set, dropping DTR/RTS\n");
/* Drop RTS/DTR */
channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
bd->bd_ops->assert_modem_signals(channel);
}
channel->ch_old_baud = 0;
/* Turn off UART interrupts for this port */
channel->ch_bd->bd_ops->uart_off(channel);
jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "finish\n");
}
static void jsm_tty_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old_termios)
{
unsigned long lock_flags;
struct jsm_channel *channel = (struct jsm_channel *)port;
spin_lock_irqsave(&port->lock, lock_flags);
channel->ch_c_cflag = termios->c_cflag;
channel->ch_c_iflag = termios->c_iflag;
channel->ch_c_oflag = termios->c_oflag;
channel->ch_c_lflag = termios->c_lflag;
channel->ch_startc = termios->c_cc[VSTART];
channel->ch_stopc = termios->c_cc[VSTOP];
channel->ch_bd->bd_ops->param(channel);
jsm_carrier(channel);
spin_unlock_irqrestore(&port->lock, lock_flags);
}
static const char *jsm_tty_type(struct uart_port *port)
{
return "jsm";
}
static void jsm_tty_release_port(struct uart_port *port)
{
}
static int jsm_tty_request_port(struct uart_port *port)
{
return 0;
}
static void jsm_config_port(struct uart_port *port, int flags)
{
port->type = PORT_JSM;
}
static struct uart_ops jsm_ops = {
.tx_empty = jsm_tty_tx_empty,
.set_mctrl = jsm_tty_set_mctrl,
.get_mctrl = jsm_tty_get_mctrl,
.stop_tx = jsm_tty_stop_tx,
.start_tx = jsm_tty_start_tx,
.send_xchar = jsm_tty_send_xchar,
.stop_rx = jsm_tty_stop_rx,
.break_ctl = jsm_tty_break,
.startup = jsm_tty_open,
.shutdown = jsm_tty_close,
.set_termios = jsm_tty_set_termios,
.type = jsm_tty_type,
.release_port = jsm_tty_release_port,
.request_port = jsm_tty_request_port,
.config_port = jsm_config_port,
};
/*
* jsm_tty_init()
*
* Init the tty subsystem. Called once per board after board has been
* downloaded and init'ed.
*/
int jsm_tty_init(struct jsm_board *brd)
{
int i;
void __iomem *vaddr;
struct jsm_channel *ch;
if (!brd)
return -ENXIO;
jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
/*
* Initialize board structure elements.
*/
brd->nasync = brd->maxports;
/*
* Allocate channel memory that might not have been allocated
* when the driver was first loaded.
*/
for (i = 0; i < brd->nasync; i++) {
if (!brd->channels[i]) {
/*
* Okay to malloc with GFP_KERNEL, we are not at
* interrupt context, and there are no locks held.
*/
brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
if (!brd->channels[i]) {
jsm_printk(CORE, ERR, &brd->pci_dev,
"%s:%d Unable to allocate memory for channel struct\n",
__FILE__, __LINE__);
}
}
}
ch = brd->channels[0];
vaddr = brd->re_map_membase;
/* Set up channel variables */
for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
if (!brd->channels[i])
continue;
spin_lock_init(&ch->ch_lock);
if (brd->bd_uart_offset == 0x200)
ch->ch_neo_uart = vaddr + (brd->bd_uart_offset * i);
ch->ch_bd = brd;
ch->ch_portnum = i;
/* .25 second delay */
ch->ch_close_delay = 250;
init_waitqueue_head(&ch->ch_flags_wait);
}
jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
return 0;
}
int jsm_uart_port_init(struct jsm_board *brd)
{
int i;
struct jsm_channel *ch;
if (!brd)
return -ENXIO;
jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
/*
* Initialize board structure elements.
*/
brd->nasync = brd->maxports;
/* Set up channel variables */
for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
if (!brd->channels[i])
continue;
brd->channels[i]->uart_port.irq = brd->irq;
brd->channels[i]->uart_port.type = PORT_JSM;
brd->channels[i]->uart_port.iotype = UPIO_MEM;
brd->channels[i]->uart_port.membase = brd->re_map_membase;
brd->channels[i]->uart_port.fifosize = 16;
brd->channels[i]->uart_port.ops = &jsm_ops;
brd->channels[i]->uart_port.line = brd->channels[i]->ch_portnum + brd->boardnum * 2;
if (uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port))
printk(KERN_INFO "Added device failed\n");
else
printk(KERN_INFO "Added device \n");
}
jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
return 0;
}
int jsm_remove_uart_port(struct jsm_board *brd)
{
int i;
struct jsm_channel *ch;
if (!brd)
return -ENXIO;
jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
/*
* Initialize board structure elements.
*/
brd->nasync = brd->maxports;
/* Set up channel variables */
for (i = 0; i < brd->nasync; i++) {
if (!brd->channels[i])
continue;
ch = brd->channels[i];
uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
}
jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
return 0;
}
void jsm_input(struct jsm_channel *ch)
{
struct jsm_board *bd;
struct tty_struct *tp;
struct tty_ldisc *ld;
u32 rmask;
u16 head;
u16 tail;
int data_len;
unsigned long lock_flags;
int flip_len = 0;
int len = 0;
int n = 0;
int s = 0;
int i = 0;
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
if (!ch)
return;
tp = ch->uart_port.info->tty;
bd = ch->ch_bd;
if(!bd)
return;
spin_lock_irqsave(&ch->ch_lock, lock_flags);
/*
*Figure the number of characters in the buffer.
*Exit immediately if none.
*/
rmask = RQUEUEMASK;
head = ch->ch_r_head & rmask;
tail = ch->ch_r_tail & rmask;
data_len = (head - tail) & rmask;
if (data_len == 0) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
return;
}
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
/*
*If the device is not open, or CREAD is off, flush
*input data and return immediately.
*/
if (!tp ||
!(tp->termios->c_cflag & CREAD) ) {
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
ch->ch_r_head = tail;
/* Force queue flow control to be released, if needed */
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
return;
}
/*
* If we are throttled, simply don't read any data.
*/
if (ch->ch_flags & CH_STOPI) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Port %d throttled, not reading any data. head: %x tail: %x\n",
ch->ch_portnum, head, tail);
return;
}
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");
/*
* If the rxbuf is empty and we are not throttled, put as much
* as we can directly into the linux TTY buffer.
*
*/
flip_len = TTY_FLIPBUF_SIZE;
len = min(data_len, flip_len);
len = min(len, (N_TTY_BUF_SIZE - 1) - tp->read_cnt);
ld = tty_ldisc_ref(tp);
/*
* If we were unable to get a reference to the ld,
* don't flush our buffer, and act like the ld doesn't
* have any space to put the data right now.
*/
if (!ld) {
len = 0;
} else {
/*
* If ld doesn't have a pointer to a receive_buf function,
* flush the data, then act like the ld doesn't have any
* space to put the data right now.
*/
if (!ld->receive_buf) {
ch->ch_r_head = ch->ch_r_tail;
len = 0;
}
}
if (len <= 0) {
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
if (ld)
tty_ldisc_deref(ld);
return;
}
len = tty_buffer_request_room(tp, len);
n = len;
/*
* n now contains the most amount of data we can copy,
* bounded either by the flip buffer size or the amount
* of data the card actually has pending...
*/
while (n) {
s = ((head >= tail) ? head : RQUEUESIZE) - tail;
s = min(s, n);
if (s <= 0)
break;
/*
* If conditions are such that ld needs to see all
* UART errors, we will have to walk each character
* and error byte and send them to the buffer one at
* a time.
*/
if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
for (i = 0; i < s; i++) {
/*
* Give the Linux ld the flags in the
* format it likes.
*/
if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_BREAK);
else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
else
tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
}
} else {
tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
}
tail += s;
n -= s;
/* Flip queue if needed */
tail &= rmask;
}
ch->ch_r_tail = tail & rmask;
ch->ch_e_tail = tail & rmask;
jsm_check_queue_flow_control(ch);
spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
/* Tell the tty layer its okay to "eat" the data now */
tty_flip_buffer_push(tp);
if (ld)
tty_ldisc_deref(ld);
jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
}
static void jsm_carrier(struct jsm_channel *ch)
{
struct jsm_board *bd;
int virt_carrier = 0;
int phys_carrier = 0;
jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev, "start\n");
if (!ch)
return;
bd = ch->ch_bd;
if (!bd)
return;
if (ch->ch_mistat & UART_MSR_DCD) {
jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
"mistat: %x D_CD: %x\n", ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
phys_carrier = 1;
}
if (ch->ch_c_cflag & CLOCAL)
virt_carrier = 1;
jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
"DCD: physical: %d virt: %d\n", phys_carrier, virt_carrier);
/*
* Test for a VIRTUAL carrier transition to HIGH.
*/
if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
/*
* When carrier rises, wake any threads waiting
* for carrier in the open routine.
*/
jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
"carrier: virt DCD rose\n");
if (waitqueue_active(&(ch->ch_flags_wait)))
wake_up_interruptible(&ch->ch_flags_wait);
}
/*
* Test for a PHYSICAL carrier transition to HIGH.
*/
if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
/*
* When carrier rises, wake any threads waiting
* for carrier in the open routine.
*/
jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
"carrier: physical DCD rose\n");
if (waitqueue_active(&(ch->ch_flags_wait)))
wake_up_interruptible(&ch->ch_flags_wait);
}
/*
* Test for a PHYSICAL transition to low, so long as we aren't
* currently ignoring physical transitions (which is what "virtual
* carrier" indicates).
*
* The transition of the virtual carrier to low really doesn't
* matter... it really only means "ignore carrier state", not
* "make pretend that carrier is there".
*/
if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
&& (phys_carrier == 0)) {
/*
* When carrier drops:
*
* Drop carrier on all open units.
*
* Flush queues, waking up any task waiting in the
* line discipline.
*
* Send a hangup to the control terminal.
*
* Enable all select calls.
*/
if (waitqueue_active(&(ch->ch_flags_wait)))
wake_up_interruptible(&ch->ch_flags_wait);
}
/*
* Make sure that our cached values reflect the current reality.
*/
if (virt_carrier == 1)
ch->ch_flags |= CH_FCAR;
else
ch->ch_flags &= ~CH_FCAR;
if (phys_carrier == 1)
ch->ch_flags |= CH_CD;
else
ch->ch_flags &= ~CH_CD;
}
void jsm_check_queue_flow_control(struct jsm_channel *ch)
{
struct board_ops *bd_ops = ch->ch_bd->bd_ops;
int qleft = 0;
/* Store how much space we have left in the queue */
if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
qleft += RQUEUEMASK + 1;
/*
* Check to see if we should enforce flow control on our queue because
* the ld (or user) isn't reading data out of our queue fast enuf.
*
* NOTE: This is done based on what the current flow control of the
* port is set for.
*
* 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
* This will cause the UART's FIFO to back up, and force
* the RTS signal to be dropped.
* 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
* the other side, in hopes it will stop sending data to us.
* 3) NONE - Nothing we can do. We will simply drop any extra data
* that gets sent into us when the queue fills up.
*/
if (qleft < 256) {
/* HWFLOW */
if (ch->ch_c_cflag & CRTSCTS) {
if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
bd_ops->disable_receiver(ch);
ch->ch_flags |= (CH_RECEIVER_OFF);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
qleft);
}
}
/* SWFLOW */
else if (ch->ch_c_iflag & IXOFF) {
if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
bd_ops->send_stop_character(ch);
ch->ch_stops_sent++;
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
}
}
}
/*
* Check to see if we should unenforce flow control because
* ld (or user) finally read enuf data out of our queue.
*
* NOTE: This is done based on what the current flow control of the
* port is set for.
*
* 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
* This will cause the UART's FIFO to raise RTS back up,
* which will allow the other side to start sending data again.
* 2) SWFLOW (IXOFF) - Send a start character to
* the other side, so it will start sending data to us again.
* 3) NONE - Do nothing. Since we didn't do anything to turn off the
* other side, we don't need to do anything now.
*/
if (qleft > (RQUEUESIZE / 2)) {
/* HWFLOW */
if (ch->ch_c_cflag & CRTSCTS) {
if (ch->ch_flags & CH_RECEIVER_OFF) {
bd_ops->enable_receiver(ch);
ch->ch_flags &= ~(CH_RECEIVER_OFF);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
"Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
qleft);
}
}
/* SWFLOW */
else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
ch->ch_stops_sent = 0;
bd_ops->send_start_character(ch);
jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
}
}
}
/*
* jsm_tty_write()
*
* Take data from the user or kernel and send it out to the FEP.
* In here exists all the Transparent Print magic as well.
*/
int jsm_tty_write(struct uart_port *port)
{
int bufcount = 0, n = 0;
int data_count = 0,data_count1 =0;
u16 head;
u16 tail;
u16 tmask;
u32 remain;
int temp_tail = port->info->xmit.tail;
struct jsm_channel *channel = (struct jsm_channel *)port;
tmask = WQUEUEMASK;
head = (channel->ch_w_head) & tmask;
tail = (channel->ch_w_tail) & tmask;
if ((bufcount = tail - head - 1) < 0)
bufcount += WQUEUESIZE;
n = bufcount;
n = min(n, 56);
remain = WQUEUESIZE - head;
data_count = 0;
if (n >= remain) {
n -= remain;
while ((port->info->xmit.head != temp_tail) &&
(data_count < remain)) {
channel->ch_wqueue[head++] =
port->info->xmit.buf[temp_tail];
temp_tail++;
temp_tail &= (UART_XMIT_SIZE - 1);
data_count++;
}
if (data_count == remain) head = 0;
}
data_count1 = 0;
if (n > 0) {
remain = n;
while ((port->info->xmit.head != temp_tail) &&
(data_count1 < remain)) {
channel->ch_wqueue[head++] =
port->info->xmit.buf[temp_tail];
temp_tail++;
temp_tail &= (UART_XMIT_SIZE - 1);
data_count1++;
}
}
port->info->xmit.tail = temp_tail;
data_count += data_count1;
if (data_count) {
head &= tmask;
channel->ch_w_head = head;
}
if (data_count) {
channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
}
return data_count;
}
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