design-question serial-driver + predefined ldisc - Nuber

[Michael Westermann]

Hallo,

I hav a projekt for POS-Systeme with a few driver's that
all use a protokoll over the serial device. 
I think it is a goo idea when i use the ldisc mechanism 
from the tty driver. 

My problem is that the ldiscs array in tty_io.c is static
predefined. I have 3 to 10 protokoll's over this mechnism. 

I think it is a good idea, to create a dynamic part on the ldiscs 
structure. 

My idea for a changed  tty_register_ldisc funktion.

int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
{
	if (disc < N_TTY || disc >= NR_LDISCS)
	    return -EINVAL;
			        
	if (disc == N_LDDYN)
	    if ((disc = get_free_ldisc()) < 0)	
    		return -EINVAL;    
	    
	    if (new_ldisc) {
	         .....	
                return (disc > N_NDDYN) ? disc : 0;	
            } else  {
                if (disc > N_LDDYN)									      set_free_ldisc(disc);
	        memset(&ldiscs[disc], 0, sizeof(struct tty_ldisc));
                return 0;	
	    }    
}

Comments ? 

Renegard's

Michael Westermann