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Diffstat (limited to 'drivers/tty/serial/jsm/jsm_tty.c')
-rw-r--r--drivers/tty/serial/jsm/jsm_tty.c828
1 files changed, 828 insertions, 0 deletions
diff --git a/drivers/tty/serial/jsm/jsm_tty.c b/drivers/tty/serial/jsm/jsm_tty.c
new file mode 100644
index 000000000..222afc270
--- /dev/null
+++ b/drivers/tty/serial/jsm/jsm_tty.c
@@ -0,0 +1,828 @@
+// SPDX-License-Identifier: GPL-2.0+
+/************************************************************************
+ * Copyright 2003 Digi International (www.digi.com)
+ *
+ * Copyright (C) 2004 IBM Corporation. All rights reserved.
+ *
+ * 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 <linux/slab.h>
+
+#include "jsm.h"
+
+static DECLARE_BITMAP(linemap, MAXLINES);
+
+static void jsm_carrier(struct jsm_channel *ch);
+
+static inline int jsm_get_mstat(struct jsm_channel *ch)
+{
+ unsigned char mstat;
+ int result;
+
+ jsm_dbg(IOCTL, &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_dbg(IOCTL, &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 =
+ container_of(port, struct jsm_channel, uart_port);
+
+ jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
+
+ result = jsm_get_mstat(channel);
+
+ if (result < 0)
+ return -ENXIO;
+
+ jsm_dbg(IOCTL, &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 =
+ container_of(port, struct jsm_channel, uart_port);
+
+ jsm_dbg(IOCTL, &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_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
+ udelay(10);
+}
+
+/*
+ * 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.
+ */
+static void jsm_tty_write(struct uart_port *port)
+{
+ struct jsm_channel *channel;
+
+ channel = container_of(port, struct jsm_channel, uart_port);
+ channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
+}
+
+static void jsm_tty_start_tx(struct uart_port *port)
+{
+ struct jsm_channel *channel =
+ container_of(port, struct jsm_channel, uart_port);
+
+ jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
+
+ channel->ch_flags &= ~(CH_STOP);
+ jsm_tty_write(port);
+
+ jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
+}
+
+static void jsm_tty_stop_tx(struct uart_port *port)
+{
+ struct jsm_channel *channel =
+ container_of(port, struct jsm_channel, uart_port);
+
+ jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
+
+ channel->ch_flags |= (CH_STOP);
+
+ jsm_dbg(IOCTL, &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 =
+ container_of(port, struct jsm_channel, uart_port);
+ struct ktermios *termios;
+
+ spin_lock_irqsave(&port->lock, lock_flags);
+ termios = &port->state->port.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 =
+ container_of(port, struct jsm_channel, uart_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 =
+ container_of(port, struct jsm_channel, uart_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);
+
+ spin_unlock_irqrestore(&port->lock, lock_flags);
+}
+
+static int jsm_tty_open(struct uart_port *port)
+{
+ unsigned long lock_flags;
+ struct jsm_board *brd;
+ struct jsm_channel *channel =
+ container_of(port, struct jsm_channel, uart_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_dbg(INIT, &channel->ch_bd->pci_dev,
+ "unable to allocate read queue buf\n");
+ return -ENOMEM;
+ }
+ }
+ if (!channel->ch_equeue) {
+ channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
+ if (!channel->ch_equeue) {
+ jsm_dbg(INIT, &channel->ch_bd->pci_dev,
+ "unable to allocate error queue buf\n");
+ return -ENOMEM;
+ }
+ }
+
+ channel->ch_flags &= ~(CH_OPENING);
+ /*
+ * Initialize if neither terminal is open.
+ */
+ jsm_dbg(OPEN, &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;
+
+ 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;
+
+ spin_lock_irqsave(&port->lock, lock_flags);
+ termios = &port->state->port.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++;
+ spin_unlock_irqrestore(&port->lock, lock_flags);
+
+ jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
+ return 0;
+}
+
+static void jsm_tty_close(struct uart_port *port)
+{
+ struct jsm_board *bd;
+ struct jsm_channel *channel =
+ container_of(port, struct jsm_channel, uart_port);
+
+ jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");
+
+ bd = channel->ch_bd;
+
+ 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_dbg(CLOSE, &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);
+ }
+
+ /* Turn off UART interrupts for this port */
+ channel->ch_bd->bd_ops->uart_off(channel);
+
+ jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "finish\n");
+}
+
+static void jsm_tty_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ const struct ktermios *old_termios)
+{
+ unsigned long lock_flags;
+ struct jsm_channel *channel =
+ container_of(port, struct jsm_channel, uart_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 const 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_dbg(INIT, &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_dbg(CORE, &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);
+ else
+ ch->ch_cls_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_dbg(INIT, &brd->pci_dev, "finish\n");
+ return 0;
+}
+
+int jsm_uart_port_init(struct jsm_board *brd)
+{
+ int i, rc;
+ unsigned int line;
+
+ if (!brd)
+ return -ENXIO;
+
+ jsm_dbg(INIT, &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;
+
+ brd->channels[i]->uart_port.irq = brd->irq;
+ brd->channels[i]->uart_port.uartclk = 14745600;
+ 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;
+ line = find_first_zero_bit(linemap, MAXLINES);
+ if (line >= MAXLINES) {
+ printk(KERN_INFO "jsm: linemap is full, added device failed\n");
+ continue;
+ } else
+ set_bit(line, linemap);
+ brd->channels[i]->uart_port.line = line;
+ rc = uart_add_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
+ if (rc) {
+ printk(KERN_INFO "jsm: Port %d failed. Aborting...\n", i);
+ return rc;
+ } else
+ printk(KERN_INFO "jsm: Port %d added\n", i);
+ }
+
+ jsm_dbg(INIT, &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_dbg(INIT, &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];
+
+ clear_bit(ch->uart_port.line, linemap);
+ uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
+ }
+
+ jsm_dbg(INIT, &brd->pci_dev, "finish\n");
+ return 0;
+}
+
+void jsm_input(struct jsm_channel *ch)
+{
+ struct jsm_board *bd;
+ struct tty_struct *tp;
+ struct tty_port *port;
+ u32 rmask;
+ u16 head;
+ u16 tail;
+ int data_len;
+ unsigned long lock_flags;
+ int len = 0;
+ int s = 0;
+ int i = 0;
+
+ jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
+
+ port = &ch->uart_port.state->port;
+ tp = port->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_dbg(READ, &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 || !C_CREAD(tp)) {
+
+ jsm_dbg(READ, &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_dbg(READ, &ch->ch_bd->pci_dev,
+ "Port %d throttled, not reading any data. head: %x tail: %x\n",
+ ch->ch_portnum, head, tail);
+ return;
+ }
+
+ jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");
+
+ len = tty_buffer_request_room(port, data_len);
+
+ /*
+ * len 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 (len) {
+ s = ((head >= tail) ? head : RQUEUESIZE) - tail;
+ s = min(s, len);
+
+ 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++) {
+ u8 chr = ch->ch_rqueue[tail + i];
+ u8 error = ch->ch_equeue[tail + i];
+ char flag = TTY_NORMAL;
+
+ /*
+ * Give the Linux ld the flags in the format it
+ * likes.
+ */
+ if (error & UART_LSR_BI)
+ flag = TTY_BREAK;
+ else if (error & UART_LSR_PE)
+ flag = TTY_PARITY;
+ else if (error & UART_LSR_FE)
+ flag = TTY_FRAME;
+
+ tty_insert_flip_char(port, chr, flag);
+ }
+ } else {
+ tty_insert_flip_string(port, ch->ch_rqueue + tail, s);
+ }
+ tail += s;
+ len -= 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(port);
+
+ jsm_dbg(IOCTL, &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_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");
+
+ bd = ch->ch_bd;
+ if (!bd)
+ return;
+
+ if (ch->ch_mistat & UART_MSR_DCD) {
+ jsm_dbg(CARR, &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_dbg(CARR, &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_dbg(CARR, &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_dbg(CARR, &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;
+
+ /* Store how much space we have left in the queue */
+ qleft = ch->ch_r_tail - ch->ch_r_head - 1;
+ if (qleft < 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_dbg(READ, &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_dbg(READ, &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_dbg(READ, &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_dbg(READ, &ch->ch_bd->pci_dev,
+ "Sending start char!\n");
+ }
+ }
+}