/* ppa.c -- low level driver for the IOMEGA PPA3
parallel port SCSI host adapter.
(The PPA3 is the embedded controller in the ZIP drive.)
(c) 1995,1996 Grant R. Guenther, grant@torque.net,
under the terms of the GNU Public License.
*/
/* This driver was developed without the benefit of any technical
specifications for the interface. Instead, a modified version of
DOSemu was used to monitor the protocol used by the DOS driver
for this adapter. I have no idea how my programming model relates
to IOMEGA's design.
IOMEGA's driver does not generate linked commands. I've never
observed a SCSI message byte in the protocol transactions, so
I am assuming that as long as linked commands are not used
we won't see any.
So far, this driver has been tested with the embedded PPA3 in the
ZIP drive, only. It can detect and adapt to 4- and 8-bit parallel
ports, but there is currently no support for EPP or ECP ports, as
I have been unable to make the DOS drivers work in these modes on
my test rig.
For more information, see the file drivers/scsi/README.ppa.
*/
#define PPA_VERSION "0.26"
/* Change these variables here or with insmod or with a LILO or LOADLIN
command line argument
*/
static int ppa_base = 0x378; /* parallel port address */
static int ppa_speed_high = 1; /* port delay in data phase */
static int ppa_speed_low = 6; /* port delay otherwise */
static int ppa_nybble = 0; /* don't force nybble mode */
#define PPA_CAN_QUEUE 1 /* use "queueing" interface */
#define PPA_SELECT_TMO 5000 /* how long to wait for target ? */
#define PPA_SPIN_TMO 5000000 /* ppa_wait loop limiter */
#define PPA_SECTOR_SIZE 512 /* for a performance hack only */
#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/tqueue.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/blk.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <asm/io.h>
#include "sd.h"
#include "hosts.h"
#include "ppa.h"
struct proc_dir_entry proc_scsi_ppa =
{ PROC_SCSI_PPA, 3, "ppa", S_IFDIR|S_IRUGO|S_IXUGO, 2 };
static int ppa_abort_flag = 0;
static int ppa_error_code = DID_OK;
static char ppa_info_string[132];
static Scsi_Cmnd *ppa_current = 0;
static void (*ppa_done) (Scsi_Cmnd *);
static int ppa_port_delay;
void out_p( short port, char byte)
{ outb(byte,ppa_base+port);
udelay(ppa_port_delay);
}
char in_p( short port)
{ return inb(ppa_base+port);
udelay(ppa_port_delay);
}
void ppa_d_pulse( char b )
{ out_p(0,b);
out_p(2,0xc); out_p(2,0xe); out_p(2,0xc); out_p(2,0x4); out_p(2,0xc);
}
void ppa_disconnect( void )
{ ppa_d_pulse(0);
ppa_d_pulse(0x3c);
ppa_d_pulse(0x20);
ppa_d_pulse(0xf);
}
void ppa_c_pulse( char b )
{ out_p(0,b);
out_p(2,0x4); out_p(2,0x6); out_p(2,0x4); out_p(2,0xc);
}
void ppa_connect( void )
{ ppa_c_pulse(0);
ppa_c_pulse(0x3c);
ppa_c_pulse(0x20);
ppa_c_pulse(0x8f);
}
void ppa_do_reset( void )
{ out_p(2,0); /* This is really just a guess */
udelay(100);
}
char ppa_select( int initiator, int target )
{ char r;
int k;
r = in_p(1);
out_p(0,(1<<target)); out_p(2,0xe); out_p(2,0xc);
out_p(0,(1<<initiator)); out_p(2,0x8);
k = 0;
while ( !(r = (in_p(1) & 0xf0)) && (k++ < PPA_SELECT_TMO)) barrier();
return r;
}
char ppa_wait( void )
/* Wait for the high bit to be set.
In principle, this could be tied to an interrupt, but the adapter
doesn't appear to be designed to support interrupts. We spin on
the 0x80 ready bit.
*/
{ int k;
char r;
ppa_error_code = DID_OK;
k = 0;
while (!((r = in_p(1)) & 0x80)
&& (k++ < PPA_SPIN_TMO) && !ppa_abort_flag ) barrier();
if (ppa_abort_flag) {
if (ppa_abort_flag == 1) ppa_error_code = DID_ABORT;
else { ppa_do_reset();
ppa_error_code = DID_RESET;
}
ppa_disconnect();
return 0;
}
if (k >= PPA_SPIN_TMO) {
ppa_error_code = DID_TIME_OUT;
ppa_disconnect();
return 0; /* command timed out */
}
return (r & 0xf0);
}
int ppa_init( void )
/* This is based on a trace of what the Iomega DOS 'guest' driver does.
I've tried several different kinds of parallel ports with guest and
coded this to react in the same ways that it does.
The return value from this function is just a hint about where the
handshaking failed.
*/
{ char r, s;
out_p(0,0xaa);
if (in_p(0) != (char) 0xaa) return 1;
ppa_disconnect();
ppa_connect();
out_p(2,0x6);
if ((in_p(1) & 0xf0) != 0xf0) return 2;
out_p(2,0x4);
if ((in_p(1) & 0xf0) != 0x80) return 3;
ppa_disconnect();
s = in_p(2);
out_p(2,0xec);
out_p(0,0x55);
r = in_p(0);
if (r != (char) 0xff) {
ppa_nybble = 1;
if (r != (char) 0x55) return 4;
out_p(0,0xaa); if (in_p(0) != (char) 0xaa) return 5;
}
out_p(2,s);
ppa_connect();
out_p(0,0x40); out_p(2,0x8); out_p(2,0xc);
ppa_disconnect();
return 0;
}
int ppa_start( Scsi_Cmnd * cmd )
{ int k;
ppa_error_code = DID_OK;
ppa_abort_flag = 0;
if (cmd->target == PPA_INITIATOR) {
ppa_error_code = DID_BAD_TARGET;
return 0;
}
ppa_connect();
if (!ppa_select(PPA_INITIATOR,cmd->target)) {
ppa_disconnect();
ppa_error_code = DID_NO_CONNECT;
return 0;
}
out_p(2,0xc);
for (k=0; k < cmd->cmd_len; k++) { /* send the command */
if (!ppa_wait()) return 0;
out_p(0,cmd->cmnd[k]);
out_p(2,0xe);
out_p(2,0xc);
}
#ifdef PPA_DEBUG
printk("PPA: command out: ");
for (k=0; k < cmd->cmd_len; k++)
printk("%3x",(cmd->cmnd[k]) & 0xff );
printk("\n");
#endif
return 1;
}
int ppa_completion( Scsi_Cmnd * cmd )
/* The bulk flag enables some optimisations in the data transfer loops,
it should be true for any command that transfers data in integral
numbers of sectors.
The driver appears to remain stable if we speed up the parallel port
i/o in this function, but not elsewhere.
*/
{ char r, l, h, v;
int dir, cnt, blen, fast, bulk;
char *buffer;
#ifdef PPA_DEBUG
int k;
#endif
if (!(r = ppa_wait())) return 0;
v = cmd->cmnd[0];
bulk = ((v==READ_6)||(v==READ_10)||(v==WRITE_6)||(v==WRITE_10));
buffer = cmd->request_buffer;
blen = cmd->request_bufflen;
cnt = 0; dir = 0;
if (r == (char) 0xc0) dir = 1; /* d0 = read c0 = write f0 = status */
ppa_port_delay = ppa_speed_high;
while (r != (char) 0xf0) {
if (((r & 0xc0) != 0xc0 ) || (cnt >= blen)) {
ppa_disconnect();
ppa_error_code = DID_ERROR;
return 0;
}
fast = bulk && ((blen - cnt) >= PPA_SECTOR_SIZE);
if (dir) do {
out_p(0,buffer[cnt++]);
out_p(2,0xe); out_p(2,0xc);
if (!fast) break;
} while (cnt % PPA_SECTOR_SIZE);
else {
if (ppa_nybble) do {
out_p(2,0x4); h = in_p(1);
out_p(2,0x6); l = in_p(1);
v = ((l >> 4) & 0x0f) + (h & 0xf0);
buffer[cnt++] = v;
if (!fast) break;
} while (cnt % PPA_SECTOR_SIZE);
else do {
out_p(2,0x25); v = in_p(0); out_p(2,0x27);
buffer[cnt++] = v;
if (!fast) break;
} while (cnt % PPA_SECTOR_SIZE);
if (!ppa_nybble) {
out_p(2,0x5); out_p(2,0x4);
}
out_p(2,0xc);
}
if (!(r = ppa_wait())) return 0;
}
ppa_port_delay = ppa_speed_low;
out_p(2,0x4); /* now read status byte */
h = in_p(1);
out_p(2,0x6);
l = in_p(1);
out_p(2,0xc);
r = ((l >> 4) & 0x0f) + (h & 0xf0);
out_p(2,0xe); out_p(2,0xc);
ppa_disconnect();
#ifdef PPA_DEBUG
printk("PPA: status: %x, data[%d]: ",r & STATUS_MASK,cnt);
if (cnt > 12) cnt = 12;
for (k=0; k < cnt; k++)
printk("%3x",buffer[k] & 0xff );
printk("\n");
#endif
return (r & STATUS_MASK);
}
/* deprecated synchronous interface */
int ppa_command( Scsi_Cmnd * cmd )
{ int s;
sti();
s = 0;
if (ppa_start(cmd))
if (ppa_wait())
s = ppa_completion(cmd);
return s + (ppa_error_code << 16);
}
/* pseudo-interrupt queueing interface */
/* Since the PPA itself doesn't generate interrupts, we use
the scheduler's task queue to generate a stream of call-backs and
complete the request when the drive is ready.
*/
static void ppa_interrupt( void *data);
static struct tq_struct ppa_tq = {0,0,ppa_interrupt,NULL};
static void ppa_interrupt( void *data)
{ Scsi_Cmnd *cmd;
void (*done) (Scsi_Cmnd *);
cmd = ppa_current;
done = ppa_done;
if (!cmd) return;
if (ppa_abort_flag) {
ppa_disconnect();
if(ppa_abort_flag == 1) cmd->result = DID_ABORT << 16;
else { ppa_do_reset();
cmd->result = DID_RESET << 16;
}
ppa_current = 0;
done(cmd);
return;
}
if (!( in_p(1) & 0x80)) {
queue_task(&ppa_tq,&tq_scheduler);
return;
}
cmd->result = ppa_completion(cmd) + (ppa_error_code << 16);
ppa_current = 0;
done(cmd);
return;
}
int ppa_queuecommand( Scsi_Cmnd * cmd, void (*done) (Scsi_Cmnd *))
{ if (ppa_current) return 0;
sti();
ppa_current = cmd;
ppa_done = done;
if (!ppa_start(cmd)) {
cmd->result = ppa_error_code << 16;
ppa_current = 0;
done(cmd);
return 0;
}
queue_task(&ppa_tq,&tq_scheduler);
return 0;
}
int ppa_detect( Scsi_Host_Template * host )
{ struct Scsi_Host *hreg;
int rs;
/* can we have the ports ? */
if (check_region(ppa_base,3)) {
printk("PPA: ports at 0x%3x are not available\n",ppa_base);
return 0;
}
/* attempt to initialise the controller */
ppa_port_delay = ppa_speed_low;
rs = ppa_init();
if (rs) {
printk("PPA: unable to initialise controller at 0x%x, error %d\n",
ppa_base,rs);
return 0;
}
/* now the glue ... */
host->proc_dir = &proc_scsi_ppa;
request_region(ppa_base,3,"ppa");
host->can_queue = PPA_CAN_QUEUE;
hreg = scsi_register(host,0);
hreg->io_port = ppa_base;
hreg->n_io_port = 3;
hreg->dma_channel = -1;
sprintf(ppa_info_string,
"PPA driver version %s using %d-bit mode on port 0x%x.",
PPA_VERSION,8-ppa_nybble*4,ppa_base);
host->name = ppa_info_string;
return 1; /* 1 host detected */
}
int ppa_biosparam( Disk * disk, kdev_t dev, int ip[])
/* Apparently the the disk->capacity attribute is off by 1 sector
for all disk drives. We add the one here, but it should really
be done in sd.c. Even if it gets fixed there, this will still
work.
*/
{ ip[0] = 0x40;
ip[1] = 0x20;
ip[2] = (disk->capacity +1) / (ip[0] * ip[1]);
if (ip[2] > 1024) {
ip[0] = 0xff;
ip[1] = 0x3f;
ip[2] = (disk->capacity +1) / (ip[0] * ip[1]);
if (ip[2] > 1023)
ip[2] = 1023;
}
return 0;
}
int ppa_abort( Scsi_Cmnd * cmd )
{ ppa_abort_flag = 1;
return SCSI_ABORT_SNOOZE;
}
int ppa_reset( Scsi_Cmnd * cmd )
{ ppa_abort_flag = 2;
return SCSI_RESET_PUNT;
}
const char *ppa_info( struct Scsi_Host * host )
{ return ppa_info_string;
}
#ifndef MODULE
/* Command line parameters (for built-in driver):
Syntax: ppa=base[,speed_high[,speed_low[,nybble]]]
For example: ppa=0x378 or ppa=0x378,0,3
*/
void ppa_setup(char *str, int *ints)
{ if (ints[0] > 0) ppa_base = ints[1];
if (ints[0] > 1) ppa_speed_high = ints[2];
if (ints[0] > 2) ppa_speed_low = ints[3];
if (ints[0] > 3) ppa_nybble = ints[4];
if (ints[0] > 4) ppa_nybble = ints[5];
}
#else
Scsi_Host_Template driver_template = PPA;
#include "scsi_module.c"
#endif
/* end of ppa.c */
