Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1001 insertions, 0 deletions

diff --git a/drivers/char/generic_serial.c b/drivers/char/generic_serial.c
new file mode 100644
index 000000000000..204a7302a4a9
--- /dev/null
+++ b/drivers/char/generic_serial.c
@@ -0,0 +1,1001 @@
+/*
+ *  generic_serial.c
+ *
+ *  Copyright (C) 1998/1999 R.E.Wolff@BitWizard.nl
+ *
+ *  written for the SX serial driver.
+ *     Contains the code that should be shared over all the serial drivers.
+ *
+ *  Credit for the idea to do it this way might go to Alan Cox. 
+ *
+ *
+ *  Version 0.1 -- December, 1998. Initial version.
+ *  Version 0.2 -- March, 1999.    Some more routines. Bugfixes. Etc.
+ *  Version 0.5 -- August, 1999.   Some more fixes. Reformat for Linus.
+ *
+ *  BitWizard is actively maintaining this file. We sometimes find
+ *  that someone submitted changes to this file. We really appreciate
+ *  your help, but please submit changes through us. We're doing our
+ *  best to be responsive.  -- REW
+ * */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/tty.h>
+#include <linux/serial.h>
+#include <linux/mm.h>
+#include <linux/generic_serial.h>
+#include <linux/interrupt.h>
+#include <linux/tty_flip.h>
+#include <linux/delay.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+#define DEBUG 
+
+static char *                  tmp_buf; 
+static DECLARE_MUTEX(tmp_buf_sem);
+
+static int gs_debug;
+
+#ifdef DEBUG
+#define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
+#else
+#define gs_dprintk(f, str...) /* nothing */
+#endif
+
+#define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __FUNCTION__)
+#define func_exit()  gs_dprintk (GS_DEBUG_FLOW, "gs: exit  %s\n", __FUNCTION__)
+#define NEW_WRITE_LOCKING 1
+#if NEW_WRITE_LOCKING
+#define DECL      /* Nothing */
+#define LOCKIT    down (& port->port_write_sem);
+#define RELEASEIT up (&port->port_write_sem);
+#else
+#define DECL      unsigned long flags;
+#define LOCKIT    save_flags (flags);cli ()
+#define RELEASEIT restore_flags (flags)
+#endif
+
+#define RS_EVENT_WRITE_WAKEUP   1
+
+module_param(gs_debug, int, 0644);
+
+
+void gs_put_char(struct tty_struct * tty, unsigned char ch)
+{
+        struct gs_port *port;
+        DECL
+
+        func_enter (); 
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+
+        if (! (port->flags & ASYNC_INITIALIZED)) return;
+
+        /* Take a lock on the serial tranmit buffer! */
+        LOCKIT;
+
+        if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
+                /* Sorry, buffer is full, drop character. Update statistics???? -- REW */
+                RELEASEIT;
+                return;
+        }
+
+        port->xmit_buf[port->xmit_head++] = ch;
+        port->xmit_head &= SERIAL_XMIT_SIZE - 1;
+        port->xmit_cnt++;  /* Characters in buffer */
+
+        RELEASEIT;
+        func_exit ();
+}
+
+
+#ifdef NEW_WRITE_LOCKING
+
+/*
+> Problems to take into account are:
+>       -1- Interrupts that empty part of the buffer.
+>       -2- page faults on the access to userspace. 
+>       -3- Other processes that are also trying to do a "write". 
+*/
+
+int gs_write(struct tty_struct * tty, 
+                    const unsigned char *buf, int count)
+{
+        struct gs_port *port;
+        int c, total = 0;
+        int t;
+
+        func_enter ();
+
+        if (!tty) return 0;
+
+        port = tty->driver_data;
+
+        if (!port) return 0;
+
+        if (! (port->flags & ASYNC_INITIALIZED))
+                return 0;
+
+        /* get exclusive "write" access to this port (problem 3) */
+        /* This is not a spinlock because we can have a disk access (page 
+                 fault) in copy_from_user */
+        down (& port->port_write_sem);
+
+        while (1) {
+
+                c = count;
+ 
+                /* This is safe because we "OWN" the "head". Noone else can 
+                   change the "head": we own the port_write_sem. */
+                /* Don't overrun the end of the buffer */
+                t = SERIAL_XMIT_SIZE - port->xmit_head;
+                if (t < c) c = t;
+ 
+                /* This is safe because the xmit_cnt can only decrease. This 
+                   would increase "t", so we might copy too little chars. */
+                /* Don't copy past the "head" of the buffer */
+                t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
+                if (t < c) c = t;
+ 
+                /* Can't copy more? break out! */
+                if (c <= 0) break;
+
+                memcpy (port->xmit_buf + port->xmit_head, buf, c);
+
+                port -> xmit_cnt += c;
+                port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
+                buf += c;
+                count -= c;
+                total += c;
+        }
+        up (& port->port_write_sem);
+
+        gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n", 
+                    (port->flags & GS_TX_INTEN)?"enabled": "disabled"); 
+
+        if (port->xmit_cnt && 
+            !tty->stopped && 
+            !tty->hw_stopped &&
+            !(port->flags & GS_TX_INTEN)) {
+                port->flags |= GS_TX_INTEN;
+                port->rd->enable_tx_interrupts (port);
+        }
+        func_exit ();
+        return total;
+}
+#else
+/*
+> Problems to take into account are:
+>       -1- Interrupts that empty part of the buffer.
+>       -2- page faults on the access to userspace. 
+>       -3- Other processes that are also trying to do a "write". 
+*/
+
+int gs_write(struct tty_struct * tty,
+                    const unsigned char *buf, int count)
+{
+        struct gs_port *port;
+        int c, total = 0;
+        int t;
+        unsigned long flags;
+
+        func_enter ();
+
+        /* The standard serial driver returns 0 in this case. 
+           That sounds to me as "No error, I just didn't get to writing any
+           bytes. Feel free to try again." 
+           The "official" way to write n bytes from buf is:
+
+                 for (nwritten = 0;nwritten < n;nwritten += rv) {
+                         rv = write (fd, buf+nwritten, n-nwritten);
+                         if (rv < 0) break; // Error: bail out. //
+                 } 
+
+           which will loop endlessly in this case. The manual page for write
+           agrees with me. In practise almost everybody writes 
+           "write (fd, buf,n);" but some people might have had to deal with 
+           incomplete writes in the past and correctly implemented it by now... 
+         */
+
+        if (!tty) return -EIO;
+
+        port = tty->driver_data;
+        if (!port || !port->xmit_buf || !tmp_buf)
+                return -EIO;
+
+        local_save_flags(flags);
+        while (1) {
+                cli();
+                c = count;
+
+                /* This is safe because we "OWN" the "head". Noone else can 
+                   change the "head": we own the port_write_sem. */
+                /* Don't overrun the end of the buffer */
+                t = SERIAL_XMIT_SIZE - port->xmit_head;
+                if (t < c) c = t;
+
+                /* This is safe because the xmit_cnt can only decrease. This 
+                   would increase "t", so we might copy too little chars. */
+                /* Don't copy past the "head" of the buffer */
+                t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
+                if (t < c) c = t;
+
+                /* Can't copy more? break out! */
+                if (c <= 0) {
+                        local_restore_flags(flags);
+                        break;
+                }
+                memcpy(port->xmit_buf + port->xmit_head, buf, c);
+                port->xmit_head = ((port->xmit_head + c) &
+                                   (SERIAL_XMIT_SIZE-1));
+                port->xmit_cnt += c;
+                local_restore_flags(flags);
+                buf += c;
+                count -= c;
+                total += c;
+        }
+
+        if (port->xmit_cnt && 
+            !tty->stopped && 
+            !tty->hw_stopped &&
+            !(port->flags & GS_TX_INTEN)) {
+                port->flags |= GS_TX_INTEN;
+                port->rd->enable_tx_interrupts (port);
+        }
+        func_exit ();
+        return total;
+}
+
+#endif
+
+
+
+int gs_write_room(struct tty_struct * tty)
+{
+        struct gs_port *port = tty->driver_data;
+        int ret;
+
+        func_enter ();
+        ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
+        if (ret < 0)
+                ret = 0;
+        func_exit ();
+        return ret;
+}
+
+
+int gs_chars_in_buffer(struct tty_struct *tty)
+{
+        struct gs_port *port = tty->driver_data;
+        func_enter ();
+
+        func_exit ();
+        return port->xmit_cnt;
+}
+
+
+static int gs_real_chars_in_buffer(struct tty_struct *tty)
+{
+        struct gs_port *port;
+        func_enter ();
+
+        if (!tty) return 0;
+        port = tty->driver_data;
+
+        if (!port->rd) return 0;
+        if (!port->rd->chars_in_buffer) return 0;
+
+        func_exit ();
+        return port->xmit_cnt + port->rd->chars_in_buffer (port);
+}
+
+
+static int gs_wait_tx_flushed (void * ptr, unsigned long timeout) 
+{
+        struct gs_port *port = ptr;
+        unsigned long end_jiffies;
+        int jiffies_to_transmit, charsleft = 0, rv = 0;
+        int rcib;
+
+        func_enter();
+
+        gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
+        if (port) {
+                gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n", 
+                port->xmit_cnt, port->xmit_buf, port->tty);
+        }
+
+        if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
+                gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
+                func_exit();
+                return -EINVAL;  /* This is an error which we don't know how to handle. */
+        }
+
+        rcib = gs_real_chars_in_buffer(port->tty);
+
+        if(rcib <= 0) {
+                gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
+                func_exit();
+                return rv;
+        }
+        /* stop trying: now + twice the time it would normally take +  seconds */
+        if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
+        end_jiffies  = jiffies; 
+        if (timeout !=  MAX_SCHEDULE_TIMEOUT)
+                end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
+        end_jiffies += timeout;
+
+        gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n", 
+                    jiffies, end_jiffies, end_jiffies-jiffies); 
+
+        /* the expression is actually jiffies < end_jiffies, but that won't
+           work around the wraparound. Tricky eh? */
+        while ((charsleft = gs_real_chars_in_buffer (port->tty)) &&
+                time_after (end_jiffies, jiffies)) {
+                /* Units check: 
+                   chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
+                   check! */
+
+                charsleft += 16; /* Allow 16 chars more to be transmitted ... */
+                jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
+                /*                                ^^^ Round up.... */
+                if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
+
+                gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
+                            "(%d chars).\n", jiffies_to_transmit, charsleft); 
+
+                msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
+                if (signal_pending (current)) {
+                        gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: "); 
+                        rv = -EINTR;
+                        break;
+                }
+        }
+
+        gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft); 
+        set_current_state (TASK_RUNNING);
+
+        func_exit();
+        return rv;
+}
+
+
+
+void gs_flush_buffer(struct tty_struct *tty)
+{
+        struct gs_port *port;
+        unsigned long flags;
+
+        func_enter ();
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+
+        /* XXX Would the write semaphore do? */
+        spin_lock_irqsave (&port->driver_lock, flags);
+        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
+        spin_unlock_irqrestore (&port->driver_lock, flags);
+
+        wake_up_interruptible(&tty->write_wait);
+        tty_wakeup(tty);
+        func_exit ();
+}
+
+
+void gs_flush_chars(struct tty_struct * tty)
+{
+        struct gs_port *port;
+
+        func_enter ();
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+
+        if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
+            !port->xmit_buf) {
+                func_exit ();
+                return;
+        }
+
+        /* Beats me -- REW */
+        port->flags |= GS_TX_INTEN;
+        port->rd->enable_tx_interrupts (port);
+        func_exit ();
+}
+
+
+void gs_stop(struct tty_struct * tty)
+{
+        struct gs_port *port;
+
+        func_enter ();
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+
+        if (port->xmit_cnt && 
+            port->xmit_buf && 
+            (port->flags & GS_TX_INTEN) ) {
+                port->flags &= ~GS_TX_INTEN;
+                port->rd->disable_tx_interrupts (port);
+        }
+        func_exit ();
+}
+
+
+void gs_start(struct tty_struct * tty)
+{
+        struct gs_port *port;
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+
+        if (port->xmit_cnt && 
+            port->xmit_buf && 
+            !(port->flags & GS_TX_INTEN) ) {
+                port->flags |= GS_TX_INTEN;
+                port->rd->enable_tx_interrupts (port);
+        }
+        func_exit ();
+}
+
+
+static void gs_shutdown_port (struct gs_port *port)
+{
+        unsigned long flags;
+
+        func_enter();
+        
+        if (!port) return;
+        
+        if (!(port->flags & ASYNC_INITIALIZED))
+                return;
+
+        spin_lock_irqsave(&port->driver_lock, flags);
+
+        if (port->xmit_buf) {
+                free_page((unsigned long) port->xmit_buf);
+                port->xmit_buf = NULL;
+        }
+
+        if (port->tty)
+                set_bit(TTY_IO_ERROR, &port->tty->flags);
+
+        port->rd->shutdown_port (port);
+
+        port->flags &= ~ASYNC_INITIALIZED;
+        spin_unlock_irqrestore(&port->driver_lock, flags);
+
+        func_exit();
+}
+
+
+void gs_hangup(struct tty_struct *tty)
+{
+        struct gs_port   *port;
+
+        func_enter ();
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+        tty = port->tty;
+        if (!tty) 
+                return;
+
+        gs_shutdown_port (port);
+        port->flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
+        port->tty = NULL;
+        port->count = 0;
+
+        wake_up_interruptible(&port->open_wait);
+        func_exit ();
+}
+
+
+int gs_block_til_ready(void *port_, struct file * filp)
+{
+        struct gs_port *port = port_;
+        DECLARE_WAITQUEUE(wait, current);
+        int    retval;
+        int    do_clocal = 0;
+        int    CD;
+        struct tty_struct *tty;
+        unsigned long flags;
+
+        func_enter ();
+
+        if (!port) return 0;
+
+        tty = port->tty;
+
+        if (!tty) return 0;
+
+        gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n"); 
+        /*
+         * If the device is in the middle of being closed, then block
+         * until it's done, and then try again.
+         */
+        if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
+                interruptible_sleep_on(&port->close_wait);
+                if (port->flags & ASYNC_HUP_NOTIFY)
+                        return -EAGAIN;
+                else
+                        return -ERESTARTSYS;
+        }
+
+        gs_dprintk (GS_DEBUG_BTR, "after hung up\n"); 
+
+        /*
+         * If non-blocking mode is set, or the port is not enabled,
+         * then make the check up front and then exit.
+         */
+        if ((filp->f_flags & O_NONBLOCK) ||
+            (tty->flags & (1 << TTY_IO_ERROR))) {
+                port->flags |= ASYNC_NORMAL_ACTIVE;
+                return 0;
+        }
+
+        gs_dprintk (GS_DEBUG_BTR, "after nonblock\n"); 
+ 
+        if (C_CLOCAL(tty))
+                do_clocal = 1;
+
+        /*
+         * Block waiting for the carrier detect and the line to become
+         * free (i.e., not in use by the callout).  While we are in
+         * this loop, port->count is dropped by one, so that
+         * rs_close() knows when to free things.  We restore it upon
+         * exit, either normal or abnormal.
+         */
+        retval = 0;
+
+        add_wait_queue(&port->open_wait, &wait);
+
+        gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n"); 
+        spin_lock_irqsave(&port->driver_lock, flags);
+        if (!tty_hung_up_p(filp)) {
+                port->count--;
+        }
+        spin_unlock_irqrestore(&port->driver_lock, flags);
+        port->blocked_open++;
+        while (1) {
+                CD = port->rd->get_CD (port);
+                gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
+                set_current_state (TASK_INTERRUPTIBLE);
+                if (tty_hung_up_p(filp) ||
+                    !(port->flags & ASYNC_INITIALIZED)) {
+                        if (port->flags & ASYNC_HUP_NOTIFY)
+                                retval = -EAGAIN;
+                        else
+                                retval = -ERESTARTSYS;
+                        break;
+                }
+                if (!(port->flags & ASYNC_CLOSING) &&
+                    (do_clocal || CD))
+                        break;
+                gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n", 
+                (int)signal_pending (current), *(long*)(&current->blocked)); 
+                if (signal_pending(current)) {
+                        retval = -ERESTARTSYS;
+                        break;
+                }
+                schedule();
+        }
+        gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
+                    port->blocked_open);
+        set_current_state (TASK_RUNNING);
+        remove_wait_queue(&port->open_wait, &wait);
+        if (!tty_hung_up_p(filp)) {
+                port->count++;
+        }
+        port->blocked_open--;
+        if (retval)
+                return retval;
+
+        port->flags |= ASYNC_NORMAL_ACTIVE;
+        func_exit ();
+        return 0;
+}                        
+
+
+void gs_close(struct tty_struct * tty, struct file * filp)
+{
+        unsigned long flags;
+        struct gs_port *port;
+        
+        func_enter ();
+
+        if (!tty) return;
+
+        port = (struct gs_port *) tty->driver_data;
+
+        if (!port) return;
+
+        if (!port->tty) {
+                /* This seems to happen when this is called from vhangup. */
+                gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->tty is NULL\n");
+                port->tty = tty;
+        }
+
+        spin_lock_irqsave(&port->driver_lock, flags);
+
+        if (tty_hung_up_p(filp)) {
+                spin_unlock_irqrestore(&port->driver_lock, flags);
+                if (port->rd->hungup)
+                        port->rd->hungup (port);
+                func_exit ();
+                return;
+        }
+
+        if ((tty->count == 1) && (port->count != 1)) {
+                printk(KERN_ERR "gs: gs_close port %p: bad port count;"
+                       " tty->count is 1, port count is %d\n", port, port->count);
+                port->count = 1;
+        }
+        if (--port->count < 0) {
+                printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->count);
+                port->count = 0;
+        }
+
+        if (port->count) {
+                gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->count);
+                spin_unlock_irqrestore(&port->driver_lock, flags);
+                func_exit ();
+                return;
+        }
+        port->flags |= ASYNC_CLOSING;
+
+        /*
+         * Now we wait for the transmit buffer to clear; and we notify 
+         * the line discipline to only process XON/XOFF characters.
+         */
+        tty->closing = 1;
+        /* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
+           tty_wait_until_sent(tty, port->closing_wait); */
+
+        /*
+         * At this point we stop accepting input.  To do this, we
+         * disable the receive line status interrupts, and tell the
+         * interrupt driver to stop checking the data ready bit in the
+         * line status register.
+         */
+
+        port->rd->disable_rx_interrupts (port);
+        spin_unlock_irqrestore(&port->driver_lock, flags);
+
+        /* close has no way of returning "EINTR", so discard return value */
+        if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
+                gs_wait_tx_flushed (port, port->closing_wait);
+
+        port->flags &= ~GS_ACTIVE;
+
+        if (tty->driver->flush_buffer)
+                tty->driver->flush_buffer(tty);
+
+        tty_ldisc_flush(tty);
+        tty->closing = 0;
+
+        port->event = 0;
+        port->rd->close (port);
+        port->rd->shutdown_port (port);
+        port->tty = NULL;
+
+        if (port->blocked_open) {
+                if (port->close_delay) {
+                        spin_unlock_irqrestore(&port->driver_lock, flags);
+                        msleep_interruptible(jiffies_to_msecs(port->close_delay));
+                        spin_lock_irqsave(&port->driver_lock, flags);
+                }
+                wake_up_interruptible(&port->open_wait);
+        }
+        port->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
+        wake_up_interruptible(&port->close_wait);
+
+        func_exit ();
+}
+
+
+static unsigned int     gs_baudrates[] = {
+  0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+  9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600
+};
+
+
+void gs_set_termios (struct tty_struct * tty, 
+                     struct termios * old_termios)
+{
+        struct gs_port *port;
+        int baudrate, tmp, rv;
+        struct termios *tiosp;
+
+        func_enter();
+
+        if (!tty) return;
+
+        port = tty->driver_data;
+
+        if (!port) return;
+        if (!port->tty) {
+                /* This seems to happen when this is called after gs_close. */
+                gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->tty is NULL\n");
+                port->tty = tty;
+        }
+
+
+        tiosp = tty->termios;
+
+        if (gs_debug & GS_DEBUG_TERMIOS) {
+                gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
+        }
+
+#if 0
+        /* This is an optimization that is only allowed for dumb cards */
+        /* Smart cards require knowledge of iflags and oflags too: that 
+           might change hardware cooking mode.... */
+#endif
+        if (old_termios) {
+                if(   (tiosp->c_iflag == old_termios->c_iflag)
+                   && (tiosp->c_oflag == old_termios->c_oflag)
+                   && (tiosp->c_cflag == old_termios->c_cflag)
+                   && (tiosp->c_lflag == old_termios->c_lflag)
+                   && (tiosp->c_line  == old_termios->c_line)
+                   && (memcmp(tiosp->c_cc, old_termios->c_cc, NCC) == 0)) {
+                        gs_dprintk(GS_DEBUG_TERMIOS, "gs_set_termios: optimized away\n");
+                        return /* 0 */;
+                }
+        } else 
+                gs_dprintk(GS_DEBUG_TERMIOS, "gs_set_termios: no old_termios: "
+                           "no optimization\n");
+
+        if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
+                if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
+                if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
+                if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
+                if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
+                if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
+                if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
+        }
+
+        baudrate = tiosp->c_cflag & CBAUD;
+        if (baudrate & CBAUDEX) {
+                baudrate &= ~CBAUDEX;
+                if ((baudrate < 1) || (baudrate > 4))
+                        tiosp->c_cflag &= ~CBAUDEX;
+                else
+                        baudrate += 15;
+        }
+
+        baudrate = gs_baudrates[baudrate];
+        if ((tiosp->c_cflag & CBAUD) == B38400) {
+                if (     (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
+                        baudrate = 57600;
+                else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
+                        baudrate = 115200;
+                else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
+                        baudrate = 230400;
+                else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
+                        baudrate = 460800;
+                else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
+                        baudrate = (port->baud_base / port->custom_divisor);
+        }
+
+        /* I recommend using THIS instead of the mess in termios (and
+           duplicating the above code). Next we should create a clean
+           interface towards this variable. If your card supports arbitrary
+           baud rates, (e.g. CD1400 or 16550 based cards) then everything
+           will be very easy..... */
+        port->baud = baudrate;
+
+        /* Two timer ticks seems enough to wakeup something like SLIP driver */
+        /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
+        tmp = (baudrate / 10 / HZ) * 2;                  
+
+        if (tmp <                 0) tmp = 0;
+        if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
+
+        port->wakeup_chars = tmp;
+
+        /* We should really wait for the characters to be all sent before
+           changing the settings. -- CAL */
+        rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
+        if (rv < 0) return /* rv */;
+
+        rv = port->rd->set_real_termios(port);
+        if (rv < 0) return /* rv */;
+
+        if ((!old_termios || 
+             (old_termios->c_cflag & CRTSCTS)) &&
+            !(      tiosp->c_cflag & CRTSCTS)) {
+                tty->stopped = 0;
+                gs_start(tty);
+        }
+
+#ifdef tytso_patch_94Nov25_1726
+        /* This "makes sense", Why is it commented out? */
+
+        if (!(old_termios->c_cflag & CLOCAL) &&
+            (tty->termios->c_cflag & CLOCAL))
+                wake_up_interruptible(&port->gs.open_wait);
+#endif
+
+        func_exit();
+        return /* 0 */;
+}
+
+
+
+/* Must be called with interrupts enabled */
+int gs_init_port(struct gs_port *port)
+{
+        unsigned long flags;
+        unsigned long page;
+
+        func_enter ();
+
+        if (!tmp_buf) {
+                page = get_zeroed_page(GFP_KERNEL);
+                spin_lock_irqsave (&port->driver_lock, flags); /* Don't expect this to make a difference. */
+                if (tmp_buf)
+                        free_page(page);
+                else
+                        tmp_buf = (unsigned char *) page;
+                spin_unlock_irqrestore (&port->driver_lock, flags);
+                if (!tmp_buf) {
+                        func_exit ();
+                        return -ENOMEM;
+                }
+        }
+
+        if (port->flags & ASYNC_INITIALIZED) {
+                func_exit ();
+                return 0;
+        }
+        if (!port->xmit_buf) {
+                /* We may sleep in get_zeroed_page() */
+                unsigned long tmp;
+
+                tmp = get_zeroed_page(GFP_KERNEL);
+                spin_lock_irqsave (&port->driver_lock, flags);
+                if (port->xmit_buf) 
+                        free_page (tmp);
+                else
+                        port->xmit_buf = (unsigned char *) tmp;
+                spin_unlock_irqrestore(&port->driver_lock, flags);
+                if (!port->xmit_buf) {
+                        func_exit ();
+                        return -ENOMEM;
+                }
+        }
+
+        spin_lock_irqsave (&port->driver_lock, flags);
+        if (port->tty) 
+                clear_bit(TTY_IO_ERROR, &port->tty->flags);
+        init_MUTEX(&port->port_write_sem);
+        port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
+        spin_unlock_irqrestore(&port->driver_lock, flags);
+        gs_set_termios(port->tty, NULL);
+        spin_lock_irqsave (&port->driver_lock, flags);
+        port->flags |= ASYNC_INITIALIZED;
+        port->flags &= ~GS_TX_INTEN;
+
+        spin_unlock_irqrestore(&port->driver_lock, flags);
+        func_exit ();
+        return 0;
+}
+
+
+int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
+{
+        struct serial_struct sio;
+
+        if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
+                return(-EFAULT);
+
+        if (!capable(CAP_SYS_ADMIN)) {
+                if ((sio.baud_base != port->baud_base) ||
+                    (sio.close_delay != port->close_delay) ||
+                    ((sio.flags & ~ASYNC_USR_MASK) !=
+                     (port->flags & ~ASYNC_USR_MASK)))
+                        return(-EPERM);
+        } 
+
+        port->flags = (port->flags & ~ASYNC_USR_MASK) |
+                (sio.flags & ASYNC_USR_MASK);
+  
+        port->baud_base = sio.baud_base;
+        port->close_delay = sio.close_delay;
+        port->closing_wait = sio.closing_wait;
+        port->custom_divisor = sio.custom_divisor;
+
+        gs_set_termios (port->tty, NULL);
+
+        return 0;
+}
+
+
+/*****************************************************************************/
+
+/*
+ *      Generate the serial struct info.
+ */
+
+int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
+{
+        struct serial_struct    sio;
+
+        memset(&sio, 0, sizeof(struct serial_struct));
+        sio.flags = port->flags;
+        sio.baud_base = port->baud_base;
+        sio.close_delay = port->close_delay;
+        sio.closing_wait = port->closing_wait;
+        sio.custom_divisor = port->custom_divisor;
+        sio.hub6 = 0;
+
+        /* If you want you can override these. */
+        sio.type = PORT_UNKNOWN;
+        sio.xmit_fifo_size = -1;
+        sio.line = -1;
+        sio.port = -1;
+        sio.irq = -1;
+
+        if (port->rd->getserial)
+                port->rd->getserial (port, &sio);
+
+        if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
+                return -EFAULT;
+        return 0;
+
+}
+
+
+void gs_got_break(struct gs_port *port)
+{
+        func_enter ();
+
+        tty_insert_flip_char(port->tty, 0, TTY_BREAK);
+        tty_schedule_flip(port->tty);
+        if (port->flags & ASYNC_SAK) {
+                do_SAK (port->tty);
+        }
+
+        func_exit ();
+}
+
+
+EXPORT_SYMBOL(gs_put_char);
+EXPORT_SYMBOL(gs_write);
+EXPORT_SYMBOL(gs_write_room);
+EXPORT_SYMBOL(gs_chars_in_buffer);
+EXPORT_SYMBOL(gs_flush_buffer);
+EXPORT_SYMBOL(gs_flush_chars);
+EXPORT_SYMBOL(gs_stop);
+EXPORT_SYMBOL(gs_start);
+EXPORT_SYMBOL(gs_hangup);
+EXPORT_SYMBOL(gs_block_til_ready);
+EXPORT_SYMBOL(gs_close);
+EXPORT_SYMBOL(gs_set_termios);
+EXPORT_SYMBOL(gs_init_port);
+EXPORT_SYMBOL(gs_setserial);
+EXPORT_SYMBOL(gs_getserial);
+EXPORT_SYMBOL(gs_got_break);
+
+MODULE_LICENSE("GPL");