/* 
        comm.c    (c) 1997-8  Grant R. Guenther <grant@torque.net>
                              Under the terms of the GNU General Public License.

	comm.c is a low-level protocol driver for some older models
	of the DataStor "Commuter" parallel to IDE adapter.  Some of
	the parallel port devices marketed by Arista currently
	use this adapter.
*/

/* Changes:

	1.01	GRG 1998.05.05  init_proto, release_proto

*/

#define COMM_VERSION      "1.01"

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <asm/io.h>

#include <linux/pata_parport.h>

/* mode codes:  0  nybble reads, 8-bit writes
                1  8-bit reads and writes
                2  8-bit EPP mode
*/

#define j44(a,b)	(((a>>3)&0x0f)|((b<<1)&0xf0))

#define P1	w2(5);w2(0xd);w2(0xd);w2(5);w2(4);
#define P2	w2(5);w2(7);w2(7);w2(5);w2(4);

/* cont = 0 - access the IDE register file 
   cont = 1 - access the IDE command set 
*/

static int  cont_map[2] = { 0x08, 0x10 };

static int comm_read_regr( PIA *pi, int cont, int regr )

{       int     l, h, r;

        r = regr + cont_map[cont];

        switch (pi->mode)  {

        case 0: w0(r); P1; w0(0);
        	w2(6); l = r1(); w0(0x80); h = r1(); w2(4);
                return j44(l,h);

        case 1: w0(r+0x20); P1; 
        	w0(0); w2(0x26); h = r0(); w2(4);
                return h;

	case 2:
	case 3:
        case 4: w3(r+0x20); (void)r1();
        	w2(0x24); h = r4(); w2(4);
                return h;

        }
        return -1;
}       

static void comm_write_regr( PIA *pi, int cont, int regr, int val )

{       int  r;

        r = regr + cont_map[cont];

        switch (pi->mode)  {

        case 0:
        case 1: w0(r); P1; w0(val); P2;
		break;

	case 2:
	case 3:
        case 4: w3(r); (void)r1(); w4(val);
                break;
        }
}

static void comm_connect ( PIA *pi  )

{       pi->saved_r0 = r0();
        pi->saved_r2 = r2();
        w2(4); w0(0xff); w2(6);
        w2(4); w0(0xaa); w2(6);
        w2(4); w0(0x00); w2(6);
        w2(4); w0(0x87); w2(6);
        w2(4); w0(0xe0); w2(0xc); w2(0xc); w2(4);
}

static void comm_disconnect ( PIA *pi )

{       w2(0); w2(0); w2(0); w2(4); 
	w0(pi->saved_r0);
        w2(pi->saved_r2);
} 

static void comm_read_block( PIA *pi, char * buf, int count )

{       int     i, l, h;

        switch (pi->mode) {
        
        case 0: w0(0x48); P1;
                for(i=0;i<count;i++) {
                        w0(0); w2(6); l = r1();
                        w0(0x80); h = r1(); w2(4);
                        buf[i] = j44(l,h);
                }
                break;

        case 1: w0(0x68); P1; w0(0);
                for(i=0;i<count;i++) {
                        w2(0x26); buf[i] = r0(); w2(0x24);
                }
		w2(4);
		break;
		
	case 2: w3(0x68); (void)r1(); w2(0x24);
		for (i=0;i<count;i++) buf[i] = r4();
		w2(4);
		break;

        case 3: w3(0x68); (void)r1(); w2(0x24);
                for (i=0;i<count/2;i++) ((u16 *)buf)[i] = r4w();
                w2(4);
                break;

        case 4: w3(0x68); (void)r1(); w2(0x24);
                for (i=0;i<count/4;i++) ((u32 *)buf)[i] = r4l();
                w2(4);
                break;
		
	}
}

/* NB: Watch out for the byte swapped writes ! */

static void comm_write_block( PIA *pi, char * buf, int count )

{       int	k;

        switch (pi->mode) {

        case 0:
        case 1: w0(0x68); P1;
        	for (k=0;k<count;k++) {
                        w2(5); w0(buf[k^1]); w2(7);
                }
                w2(5); w2(4);
                break;

        case 2: w3(0x48); (void)r1();
                for (k=0;k<count;k++) w4(buf[k^1]);
                break;

        case 3: w3(0x48); (void)r1();
                for (k=0;k<count/2;k++) w4w(pi_swab16(buf,k));
                break;

        case 4: w3(0x48); (void)r1();
                for (k=0;k<count/4;k++) w4l(pi_swab32(buf,k));
                break;


        }
}

static void comm_log_adapter( PIA *pi, char * scratch, int verbose )

{       char    *mode_string[5] = {"4-bit","8-bit","EPP-8","EPP-16","EPP-32"};

        printk("%s: comm %s, DataStor Commuter at 0x%x, ",
                pi->device,COMM_VERSION,pi->port);
        printk("mode %d (%s), delay %d\n",pi->mode,
		mode_string[pi->mode],pi->delay);

}

static struct pi_protocol comm = {
	.owner		= THIS_MODULE,
	.name		= "comm",
	.max_mode	= 5,
	.epp_first	= 2,
	.default_delay	= 1,
	.max_units	= 1,
	.write_regr	= comm_write_regr,
	.read_regr	= comm_read_regr,
	.write_block	= comm_write_block,
	.read_block	= comm_read_block,
	.connect	= comm_connect,
	.disconnect	= comm_disconnect,
	.log_adapter	= comm_log_adapter,
};

static int __init comm_init(void)
{
	return paride_register(&comm);
}

static void __exit comm_exit(void)
{
	paride_unregister(&comm);
}

MODULE_LICENSE("GPL");
module_init(comm_init)
module_exit(comm_exit)