Re: [PATCH] ptmx: adding handshake support

[sander van ginkel <sander@van-ginkel.eu>]

I've created a new patch, build against linux-2.6.25-rc8.

Signed-off-by: Sander van Ginkel <sander@van-ginkel.eu>

===================================================================

diff -pru linux-2.6.25-rc8.orig/drivers/char/pty.c 
linux-2.6.25-rc8/drivers/char/pty.c
--- linux-2.6.25-rc8.orig/drivers/char/pty.c    2008-04-01 
21:44:26.000000000 +0200
+++ linux-2.6.25-rc8/drivers/char/pty.c    2008-04-13 16:40:03.000000000 
+0200
@@ -7,6 +7,8 @@
  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
  *  Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
  *      waiting writers -- Sapan Bhatia <sapan@corewars.org>
+ *  Added support for MCR/MSR, used for serial over ethernet
+ *    -- Sander van Ginkel <sander@van-ginkel.eu>
  *
  *
  */
@@ -196,6 +198,7 @@ static void pty_flush_buffer(struct tty_
 
 static int pty_open(struct tty_struct *tty, struct file * filp)
 {
+    unsigned int    *mcrmsr;
     int    retval = -ENODEV;
 
     if (!tty || !tty->link)
@@ -212,11 +215,56 @@ static int pty_open(struct tty_struct *t
     clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
     set_bit(TTY_THROTTLED, &tty->flags);
     set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+    /* initialize the pointer in case something fails */
+   
+    tty->driver_data = NULL;                         
+    tty->link->driver_data = NULL;
+
+    /* first time accessing this device, let's create it */
+
+    mcrmsr = kmalloc(sizeof(*mcrmsr), GFP_KERNEL);
+
+    if (mcrmsr != NULL) {
+
+        /* save our data within the tty structure */
+
+        *mcrmsr=0;
+
+        tty->driver_data = mcrmsr;
+        tty->link->driver_data = mcrmsr;
+    }
+    else
+    {
+        goto out;
+    }       
+
     retval = 0;
+
 out:
     return retval;
 }
 
+static int pty_tiocmget(struct tty_struct *tty, struct file *file)
+{
+    unsigned int *mcrmsr;
+
+    mcrmsr = tty->driver_data;
+
+    return *mcrmsr;
+}
+
+static int pty_tiocmset(struct tty_struct *tty, struct file 
*file,unsigned int set, unsigned int clear)
+{
+    unsigned int *mcrmsr;
+
+    mcrmsr = tty->driver_data;
+    *mcrmsr=set;
+    tty->driver_data=mcrmsr;
+
+    return 0;
+}
+
 static void pty_set_termios(struct tty_struct *tty, struct ktermios 
*old_termios)
 {
         tty->termios->c_cflag &= ~(CSIZE | PARENB);
@@ -232,6 +280,8 @@ static const struct tty_operations pty_o
     .chars_in_buffer = pty_chars_in_buffer,
     .unthrottle = pty_unthrottle,
     .set_termios = pty_set_termios,
+    .tiocmget = pty_tiocmget,
+    .tiocmset = pty_tiocmset,
 };
 
 /* Traditional BSD devices */
@@ -364,11 +414,27 @@ static struct ctl_table pty_root_table[]
 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
                 unsigned int cmd, unsigned long arg)
 {
+    unsigned int value;
+    unsigned int *mcrmsr;
+
+        mcrmsr=tty->driver_data;
+
     switch (cmd) {
     case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
         return pty_set_lock(tty, (int __user *)arg);
     case TIOCGPTN: /* Get PT Number */
         return put_user(tty->index, (unsigned int __user *)arg);
+
+    case VMCRMSR: /* Set all of the handshake line, even the normally 
read only */
+        {
+        if (copy_from_user(&value,(unsigned int *)arg,sizeof(unsigned 
int)))
+            return -EFAULT;
+
+        *mcrmsr=value;
+        tty->driver_data=mcrmsr;
+
+        return 0;
+        }         
     }
 
     return -ENOIOCTLCMD;