xref: /openbmc/linux/drivers/scsi/ppa.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /* ppa.c   --  low level driver for the IOMEGA PPA3
2  * parallel port SCSI host adapter.
3  *
4  * (The PPA3 is the embedded controller in the ZIP drive.)
5  *
6  * (c) 1995,1996 Grant R. Guenther, grant@torque.net,
7  * under the terms of the GNU General Public License.
8  *
9  */
10 
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/blkdev.h>
15 #include <linux/parport.h>
16 #include <linux/workqueue.h>
17 #include <linux/delay.h>
18 #include <linux/jiffies.h>
19 #include <asm/io.h>
20 
21 #include <scsi/scsi.h>
22 #include <scsi/scsi_cmnd.h>
23 #include <scsi/scsi_device.h>
24 #include <scsi/scsi_host.h>
25 
26 
27 static void ppa_reset_pulse(unsigned int base);
28 
29 typedef struct {
30 	struct pardevice *dev;	/* Parport device entry         */
31 	int base;		/* Actual port address          */
32 	int mode;		/* Transfer mode                */
33 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
34 	struct delayed_work ppa_tq;	/* Polling interrupt stuff       */
35 	unsigned long jstart;	/* Jiffies at start             */
36 	unsigned long recon_tmo;	/* How many usecs to wait for reconnection (6th bit) */
37 	unsigned int failed:1;	/* Failure flag                 */
38 	unsigned wanted:1;	/* Parport sharing busy flag    */
39 	wait_queue_head_t *waiting;
40 	struct Scsi_Host *host;
41 	struct list_head list;
42 } ppa_struct;
43 
44 #include  "ppa.h"
45 
46 static inline ppa_struct *ppa_dev(struct Scsi_Host *host)
47 {
48 	return *(ppa_struct **)&host->hostdata;
49 }
50 
51 static DEFINE_SPINLOCK(arbitration_lock);
52 
53 static void got_it(ppa_struct *dev)
54 {
55 	dev->base = dev->dev->port->base;
56 	if (dev->cur_cmd)
57 		dev->cur_cmd->SCp.phase = 1;
58 	else
59 		wake_up(dev->waiting);
60 }
61 
62 static void ppa_wakeup(void *ref)
63 {
64 	ppa_struct *dev = (ppa_struct *) ref;
65 	unsigned long flags;
66 
67 	spin_lock_irqsave(&arbitration_lock, flags);
68 	if (dev->wanted) {
69 		parport_claim(dev->dev);
70 		got_it(dev);
71 		dev->wanted = 0;
72 	}
73 	spin_unlock_irqrestore(&arbitration_lock, flags);
74 	return;
75 }
76 
77 static int ppa_pb_claim(ppa_struct *dev)
78 {
79 	unsigned long flags;
80 	int res = 1;
81 	spin_lock_irqsave(&arbitration_lock, flags);
82 	if (parport_claim(dev->dev) == 0) {
83 		got_it(dev);
84 		res = 0;
85 	}
86 	dev->wanted = res;
87 	spin_unlock_irqrestore(&arbitration_lock, flags);
88 	return res;
89 }
90 
91 static void ppa_pb_dismiss(ppa_struct *dev)
92 {
93 	unsigned long flags;
94 	int wanted;
95 	spin_lock_irqsave(&arbitration_lock, flags);
96 	wanted = dev->wanted;
97 	dev->wanted = 0;
98 	spin_unlock_irqrestore(&arbitration_lock, flags);
99 	if (!wanted)
100 		parport_release(dev->dev);
101 }
102 
103 static inline void ppa_pb_release(ppa_struct *dev)
104 {
105 	parport_release(dev->dev);
106 }
107 
108 /*
109  * Start of Chipset kludges
110  */
111 
112 /* This is to give the ppa driver a way to modify the timings (and other
113  * parameters) by writing to the /proc/scsi/ppa/0 file.
114  * Very simple method really... (To simple, no error checking :( )
115  * Reason: Kernel hackers HATE having to unload and reload modules for
116  * testing...
117  * Also gives a method to use a script to obtain optimum timings (TODO)
118  */
119 
120 static inline int ppa_proc_write(ppa_struct *dev, char *buffer, int length)
121 {
122 	unsigned long x;
123 
124 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
125 		x = simple_strtoul(buffer + 5, NULL, 0);
126 		dev->mode = x;
127 		return length;
128 	}
129 	if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
130 		x = simple_strtoul(buffer + 10, NULL, 0);
131 		dev->recon_tmo = x;
132 		printk(KERN_INFO "ppa: recon_tmo set to %ld\n", x);
133 		return length;
134 	}
135 	printk(KERN_WARNING "ppa /proc: invalid variable\n");
136 	return -EINVAL;
137 }
138 
139 static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
140 {
141 	int len = 0;
142 	ppa_struct *dev = ppa_dev(host);
143 
144 	if (inout)
145 		return ppa_proc_write(dev, buffer, length);
146 
147 	len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
148 	len +=
149 	    sprintf(buffer + len, "Parport : %s\n",
150 		    dev->dev->port->name);
151 	len +=
152 	    sprintf(buffer + len, "Mode    : %s\n",
153 		    PPA_MODE_STRING[dev->mode]);
154 #if PPA_DEBUG > 0
155 	len +=
156 	    sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
157 #endif
158 
159 	/* Request for beyond end of buffer */
160 	if (offset > length)
161 		return 0;
162 
163 	*start = buffer + offset;
164 	len -= offset;
165 	if (len > length)
166 		len = length;
167 	return len;
168 }
169 
170 static int device_check(ppa_struct *dev);
171 
172 #if PPA_DEBUG > 0
173 #define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
174 	   y, __func__, __LINE__); ppa_fail_func(x,y);
175 static inline void ppa_fail_func(ppa_struct *dev, int error_code)
176 #else
177 static inline void ppa_fail(ppa_struct *dev, int error_code)
178 #endif
179 {
180 	/* If we fail a device then we trash status / message bytes */
181 	if (dev->cur_cmd) {
182 		dev->cur_cmd->result = error_code << 16;
183 		dev->failed = 1;
184 	}
185 }
186 
187 /*
188  * Wait for the high bit to be set.
189  *
190  * In principle, this could be tied to an interrupt, but the adapter
191  * doesn't appear to be designed to support interrupts.  We spin on
192  * the 0x80 ready bit.
193  */
194 static unsigned char ppa_wait(ppa_struct *dev)
195 {
196 	int k;
197 	unsigned short ppb = dev->base;
198 	unsigned char r;
199 
200 	k = PPA_SPIN_TMO;
201 	/* Wait for bit 6 and 7 - PJC */
202 	for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
203 		udelay(1);
204 		r = r_str(ppb);
205 	}
206 
207 	/*
208 	 * return some status information.
209 	 * Semantics: 0xc0 = ZIP wants more data
210 	 *            0xd0 = ZIP wants to send more data
211 	 *            0xe0 = ZIP is expecting SCSI command data
212 	 *            0xf0 = end of transfer, ZIP is sending status
213 	 */
214 	if (k)
215 		return (r & 0xf0);
216 
217 	/* Counter expired - Time out occurred */
218 	ppa_fail(dev, DID_TIME_OUT);
219 	printk(KERN_WARNING "ppa timeout in ppa_wait\n");
220 	return 0;		/* command timed out */
221 }
222 
223 /*
224  * Clear EPP Timeout Bit
225  */
226 static inline void epp_reset(unsigned short ppb)
227 {
228 	int i;
229 
230 	i = r_str(ppb);
231 	w_str(ppb, i);
232 	w_str(ppb, i & 0xfe);
233 }
234 
235 /*
236  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
237  */
238 static inline void ecp_sync(ppa_struct *dev)
239 {
240 	int i, ppb_hi = dev->dev->port->base_hi;
241 
242 	if (ppb_hi == 0)
243 		return;
244 
245 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
246 		for (i = 0; i < 100; i++) {
247 			if (r_ecr(ppb_hi) & 0x01)
248 				return;
249 			udelay(5);
250 		}
251 		printk(KERN_WARNING "ppa: ECP sync failed as data still present in FIFO.\n");
252 	}
253 }
254 
255 static int ppa_byte_out(unsigned short base, const char *buffer, int len)
256 {
257 	int i;
258 
259 	for (i = len; i; i--) {
260 		w_dtr(base, *buffer++);
261 		w_ctr(base, 0xe);
262 		w_ctr(base, 0xc);
263 	}
264 	return 1;		/* All went well - we hope! */
265 }
266 
267 static int ppa_byte_in(unsigned short base, char *buffer, int len)
268 {
269 	int i;
270 
271 	for (i = len; i; i--) {
272 		*buffer++ = r_dtr(base);
273 		w_ctr(base, 0x27);
274 		w_ctr(base, 0x25);
275 	}
276 	return 1;		/* All went well - we hope! */
277 }
278 
279 static int ppa_nibble_in(unsigned short base, char *buffer, int len)
280 {
281 	for (; len; len--) {
282 		unsigned char h;
283 
284 		w_ctr(base, 0x4);
285 		h = r_str(base) & 0xf0;
286 		w_ctr(base, 0x6);
287 		*buffer++ = h | ((r_str(base) & 0xf0) >> 4);
288 	}
289 	return 1;		/* All went well - we hope! */
290 }
291 
292 static int ppa_out(ppa_struct *dev, char *buffer, int len)
293 {
294 	int r;
295 	unsigned short ppb = dev->base;
296 
297 	r = ppa_wait(dev);
298 
299 	if ((r & 0x50) != 0x40) {
300 		ppa_fail(dev, DID_ERROR);
301 		return 0;
302 	}
303 	switch (dev->mode) {
304 	case PPA_NIBBLE:
305 	case PPA_PS2:
306 		/* 8 bit output, with a loop */
307 		r = ppa_byte_out(ppb, buffer, len);
308 		break;
309 
310 	case PPA_EPP_32:
311 	case PPA_EPP_16:
312 	case PPA_EPP_8:
313 		epp_reset(ppb);
314 		w_ctr(ppb, 0x4);
315 #ifdef CONFIG_SCSI_IZIP_EPP16
316 		if (!(((long) buffer | len) & 0x01))
317 			outsw(ppb + 4, buffer, len >> 1);
318 #else
319 		if (!(((long) buffer | len) & 0x03))
320 			outsl(ppb + 4, buffer, len >> 2);
321 #endif
322 		else
323 			outsb(ppb + 4, buffer, len);
324 		w_ctr(ppb, 0xc);
325 		r = !(r_str(ppb) & 0x01);
326 		w_ctr(ppb, 0xc);
327 		ecp_sync(dev);
328 		break;
329 
330 	default:
331 		printk(KERN_ERR "PPA: bug in ppa_out()\n");
332 		r = 0;
333 	}
334 	return r;
335 }
336 
337 static int ppa_in(ppa_struct *dev, char *buffer, int len)
338 {
339 	int r;
340 	unsigned short ppb = dev->base;
341 
342 	r = ppa_wait(dev);
343 
344 	if ((r & 0x50) != 0x50) {
345 		ppa_fail(dev, DID_ERROR);
346 		return 0;
347 	}
348 	switch (dev->mode) {
349 	case PPA_NIBBLE:
350 		/* 4 bit input, with a loop */
351 		r = ppa_nibble_in(ppb, buffer, len);
352 		w_ctr(ppb, 0xc);
353 		break;
354 
355 	case PPA_PS2:
356 		/* 8 bit input, with a loop */
357 		w_ctr(ppb, 0x25);
358 		r = ppa_byte_in(ppb, buffer, len);
359 		w_ctr(ppb, 0x4);
360 		w_ctr(ppb, 0xc);
361 		break;
362 
363 	case PPA_EPP_32:
364 	case PPA_EPP_16:
365 	case PPA_EPP_8:
366 		epp_reset(ppb);
367 		w_ctr(ppb, 0x24);
368 #ifdef CONFIG_SCSI_IZIP_EPP16
369 		if (!(((long) buffer | len) & 0x01))
370 			insw(ppb + 4, buffer, len >> 1);
371 #else
372 		if (!(((long) buffer | len) & 0x03))
373 			insl(ppb + 4, buffer, len >> 2);
374 #endif
375 		else
376 			insb(ppb + 4, buffer, len);
377 		w_ctr(ppb, 0x2c);
378 		r = !(r_str(ppb) & 0x01);
379 		w_ctr(ppb, 0x2c);
380 		ecp_sync(dev);
381 		break;
382 
383 	default:
384 		printk(KERN_ERR "PPA: bug in ppa_ins()\n");
385 		r = 0;
386 		break;
387 	}
388 	return r;
389 }
390 
391 /* end of ppa_io.h */
392 static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
393 {
394 	w_dtr(ppb, b);
395 	w_ctr(ppb, 0xc);
396 	w_ctr(ppb, 0xe);
397 	w_ctr(ppb, 0xc);
398 	w_ctr(ppb, 0x4);
399 	w_ctr(ppb, 0xc);
400 }
401 
402 static void ppa_disconnect(ppa_struct *dev)
403 {
404 	unsigned short ppb = dev->base;
405 
406 	ppa_d_pulse(ppb, 0);
407 	ppa_d_pulse(ppb, 0x3c);
408 	ppa_d_pulse(ppb, 0x20);
409 	ppa_d_pulse(ppb, 0xf);
410 }
411 
412 static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
413 {
414 	w_dtr(ppb, b);
415 	w_ctr(ppb, 0x4);
416 	w_ctr(ppb, 0x6);
417 	w_ctr(ppb, 0x4);
418 	w_ctr(ppb, 0xc);
419 }
420 
421 static inline void ppa_connect(ppa_struct *dev, int flag)
422 {
423 	unsigned short ppb = dev->base;
424 
425 	ppa_c_pulse(ppb, 0);
426 	ppa_c_pulse(ppb, 0x3c);
427 	ppa_c_pulse(ppb, 0x20);
428 	if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
429 		ppa_c_pulse(ppb, 0xcf);
430 	else
431 		ppa_c_pulse(ppb, 0x8f);
432 }
433 
434 static int ppa_select(ppa_struct *dev, int target)
435 {
436 	int k;
437 	unsigned short ppb = dev->base;
438 
439 	/*
440 	 * Bit 6 (0x40) is the device selected bit.
441 	 * First we must wait till the current device goes off line...
442 	 */
443 	k = PPA_SELECT_TMO;
444 	do {
445 		k--;
446 		udelay(1);
447 	} while ((r_str(ppb) & 0x40) && (k));
448 	if (!k)
449 		return 0;
450 
451 	w_dtr(ppb, (1 << target));
452 	w_ctr(ppb, 0xe);
453 	w_ctr(ppb, 0xc);
454 	w_dtr(ppb, 0x80);	/* This is NOT the initator */
455 	w_ctr(ppb, 0x8);
456 
457 	k = PPA_SELECT_TMO;
458 	do {
459 		k--;
460 		udelay(1);
461 	}
462 	while (!(r_str(ppb) & 0x40) && (k));
463 	if (!k)
464 		return 0;
465 
466 	return 1;
467 }
468 
469 /*
470  * This is based on a trace of what the Iomega DOS 'guest' driver does.
471  * I've tried several different kinds of parallel ports with guest and
472  * coded this to react in the same ways that it does.
473  *
474  * The return value from this function is just a hint about where the
475  * handshaking failed.
476  *
477  */
478 static int ppa_init(ppa_struct *dev)
479 {
480 	int retv;
481 	unsigned short ppb = dev->base;
482 
483 	ppa_disconnect(dev);
484 	ppa_connect(dev, CONNECT_NORMAL);
485 
486 	retv = 2;		/* Failed */
487 
488 	w_ctr(ppb, 0xe);
489 	if ((r_str(ppb) & 0x08) == 0x08)
490 		retv--;
491 
492 	w_ctr(ppb, 0xc);
493 	if ((r_str(ppb) & 0x08) == 0x00)
494 		retv--;
495 
496 	if (!retv)
497 		ppa_reset_pulse(ppb);
498 	udelay(1000);		/* Allow devices to settle down */
499 	ppa_disconnect(dev);
500 	udelay(1000);		/* Another delay to allow devices to settle */
501 
502 	if (retv)
503 		return -EIO;
504 
505 	return device_check(dev);
506 }
507 
508 static inline int ppa_send_command(struct scsi_cmnd *cmd)
509 {
510 	ppa_struct *dev = ppa_dev(cmd->device->host);
511 	int k;
512 
513 	w_ctr(dev->base, 0x0c);
514 
515 	for (k = 0; k < cmd->cmd_len; k++)
516 		if (!ppa_out(dev, &cmd->cmnd[k], 1))
517 			return 0;
518 	return 1;
519 }
520 
521 /*
522  * The bulk flag enables some optimisations in the data transfer loops,
523  * it should be true for any command that transfers data in integral
524  * numbers of sectors.
525  *
526  * The driver appears to remain stable if we speed up the parallel port
527  * i/o in this function, but not elsewhere.
528  */
529 static int ppa_completion(struct scsi_cmnd *cmd)
530 {
531 	/* Return codes:
532 	 * -1     Error
533 	 *  0     Told to schedule
534 	 *  1     Finished data transfer
535 	 */
536 	ppa_struct *dev = ppa_dev(cmd->device->host);
537 	unsigned short ppb = dev->base;
538 	unsigned long start_jiffies = jiffies;
539 
540 	unsigned char r, v;
541 	int fast, bulk, status;
542 
543 	v = cmd->cmnd[0];
544 	bulk = ((v == READ_6) ||
545 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
546 
547 	/*
548 	 * We only get here if the drive is ready to comunicate,
549 	 * hence no need for a full ppa_wait.
550 	 */
551 	r = (r_str(ppb) & 0xf0);
552 
553 	while (r != (unsigned char) 0xf0) {
554 		/*
555 		 * If we have been running for more than a full timer tick
556 		 * then take a rest.
557 		 */
558 		if (time_after(jiffies, start_jiffies + 1))
559 			return 0;
560 
561 		if ((cmd->SCp.this_residual <= 0)) {
562 			ppa_fail(dev, DID_ERROR);
563 			return -1;	/* ERROR_RETURN */
564 		}
565 
566 		/* On some hardware we have SCSI disconnected (6th bit low)
567 		 * for about 100usecs. It is too expensive to wait a
568 		 * tick on every loop so we busy wait for no more than
569 		 * 500usecs to give the drive a chance first. We do not
570 		 * change things for "normal" hardware since generally
571 		 * the 6th bit is always high.
572 		 * This makes the CPU load higher on some hardware
573 		 * but otherwise we can not get more than 50K/secs
574 		 * on this problem hardware.
575 		 */
576 		if ((r & 0xc0) != 0xc0) {
577 			/* Wait for reconnection should be no more than
578 			 * jiffy/2 = 5ms = 5000 loops
579 			 */
580 			unsigned long k = dev->recon_tmo;
581 			for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
582 			     k--)
583 				udelay(1);
584 
585 			if (!k)
586 				return 0;
587 		}
588 
589 		/* determine if we should use burst I/O */
590 		fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
591 		    ? PPA_BURST_SIZE : 1;
592 
593 		if (r == (unsigned char) 0xc0)
594 			status = ppa_out(dev, cmd->SCp.ptr, fast);
595 		else
596 			status = ppa_in(dev, cmd->SCp.ptr, fast);
597 
598 		cmd->SCp.ptr += fast;
599 		cmd->SCp.this_residual -= fast;
600 
601 		if (!status) {
602 			ppa_fail(dev, DID_BUS_BUSY);
603 			return -1;	/* ERROR_RETURN */
604 		}
605 		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
606 			/* if scatter/gather, advance to the next segment */
607 			if (cmd->SCp.buffers_residual--) {
608 				cmd->SCp.buffer++;
609 				cmd->SCp.this_residual =
610 				    cmd->SCp.buffer->length;
611 				cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
612 			}
613 		}
614 		/* Now check to see if the drive is ready to comunicate */
615 		r = (r_str(ppb) & 0xf0);
616 		/* If not, drop back down to the scheduler and wait a timer tick */
617 		if (!(r & 0x80))
618 			return 0;
619 	}
620 	return 1;		/* FINISH_RETURN */
621 }
622 
623 /*
624  * Since the PPA itself doesn't generate interrupts, we use
625  * the scheduler's task queue to generate a stream of call-backs and
626  * complete the request when the drive is ready.
627  */
628 static void ppa_interrupt(struct work_struct *work)
629 {
630 	ppa_struct *dev = container_of(work, ppa_struct, ppa_tq.work);
631 	struct scsi_cmnd *cmd = dev->cur_cmd;
632 
633 	if (!cmd) {
634 		printk(KERN_ERR "PPA: bug in ppa_interrupt\n");
635 		return;
636 	}
637 	if (ppa_engine(dev, cmd)) {
638 		schedule_delayed_work(&dev->ppa_tq, 1);
639 		return;
640 	}
641 	/* Command must of completed hence it is safe to let go... */
642 #if PPA_DEBUG > 0
643 	switch ((cmd->result >> 16) & 0xff) {
644 	case DID_OK:
645 		break;
646 	case DID_NO_CONNECT:
647 		printk(KERN_DEBUG "ppa: no device at SCSI ID %i\n", cmd->device->target);
648 		break;
649 	case DID_BUS_BUSY:
650 		printk(KERN_DEBUG "ppa: BUS BUSY - EPP timeout detected\n");
651 		break;
652 	case DID_TIME_OUT:
653 		printk(KERN_DEBUG "ppa: unknown timeout\n");
654 		break;
655 	case DID_ABORT:
656 		printk(KERN_DEBUG "ppa: told to abort\n");
657 		break;
658 	case DID_PARITY:
659 		printk(KERN_DEBUG "ppa: parity error (???)\n");
660 		break;
661 	case DID_ERROR:
662 		printk(KERN_DEBUG "ppa: internal driver error\n");
663 		break;
664 	case DID_RESET:
665 		printk(KERN_DEBUG "ppa: told to reset device\n");
666 		break;
667 	case DID_BAD_INTR:
668 		printk(KERN_WARNING "ppa: bad interrupt (???)\n");
669 		break;
670 	default:
671 		printk(KERN_WARNING "ppa: bad return code (%02x)\n",
672 		       (cmd->result >> 16) & 0xff);
673 	}
674 #endif
675 
676 	if (cmd->SCp.phase > 1)
677 		ppa_disconnect(dev);
678 
679 	ppa_pb_dismiss(dev);
680 
681 	dev->cur_cmd = NULL;
682 
683 	cmd->scsi_done(cmd);
684 }
685 
686 static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
687 {
688 	unsigned short ppb = dev->base;
689 	unsigned char l = 0, h = 0;
690 	int retv;
691 
692 	/* First check for any errors that may of occurred
693 	 * Here we check for internal errors
694 	 */
695 	if (dev->failed)
696 		return 0;
697 
698 	switch (cmd->SCp.phase) {
699 	case 0:		/* Phase 0 - Waiting for parport */
700 		if (time_after(jiffies, dev->jstart + HZ)) {
701 			/*
702 			 * We waited more than a second
703 			 * for parport to call us
704 			 */
705 			ppa_fail(dev, DID_BUS_BUSY);
706 			return 0;
707 		}
708 		return 1;	/* wait until ppa_wakeup claims parport */
709 	case 1:		/* Phase 1 - Connected */
710 		{		/* Perform a sanity check for cable unplugged */
711 			int retv = 2;	/* Failed */
712 
713 			ppa_connect(dev, CONNECT_EPP_MAYBE);
714 
715 			w_ctr(ppb, 0xe);
716 			if ((r_str(ppb) & 0x08) == 0x08)
717 				retv--;
718 
719 			w_ctr(ppb, 0xc);
720 			if ((r_str(ppb) & 0x08) == 0x00)
721 				retv--;
722 
723 			if (retv) {
724 				if (time_after(jiffies, dev->jstart + (1 * HZ))) {
725 					printk(KERN_ERR "ppa: Parallel port cable is unplugged.\n");
726 					ppa_fail(dev, DID_BUS_BUSY);
727 					return 0;
728 				} else {
729 					ppa_disconnect(dev);
730 					return 1;	/* Try again in a jiffy */
731 				}
732 			}
733 			cmd->SCp.phase++;
734 		}
735 
736 	case 2:		/* Phase 2 - We are now talking to the scsi bus */
737 		if (!ppa_select(dev, scmd_id(cmd))) {
738 			ppa_fail(dev, DID_NO_CONNECT);
739 			return 0;
740 		}
741 		cmd->SCp.phase++;
742 
743 	case 3:		/* Phase 3 - Ready to accept a command */
744 		w_ctr(ppb, 0x0c);
745 		if (!(r_str(ppb) & 0x80))
746 			return 1;
747 
748 		if (!ppa_send_command(cmd))
749 			return 0;
750 		cmd->SCp.phase++;
751 
752 	case 4:		/* Phase 4 - Setup scatter/gather buffers */
753 		if (scsi_bufflen(cmd)) {
754 			cmd->SCp.buffer = scsi_sglist(cmd);
755 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
756 			cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
757 		} else {
758 			cmd->SCp.buffer = NULL;
759 			cmd->SCp.this_residual = 0;
760 			cmd->SCp.ptr = NULL;
761 		}
762 		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
763 		cmd->SCp.phase++;
764 
765 	case 5:		/* Phase 5 - Data transfer stage */
766 		w_ctr(ppb, 0x0c);
767 		if (!(r_str(ppb) & 0x80))
768 			return 1;
769 
770 		retv = ppa_completion(cmd);
771 		if (retv == -1)
772 			return 0;
773 		if (retv == 0)
774 			return 1;
775 		cmd->SCp.phase++;
776 
777 	case 6:		/* Phase 6 - Read status/message */
778 		cmd->result = DID_OK << 16;
779 		/* Check for data overrun */
780 		if (ppa_wait(dev) != (unsigned char) 0xf0) {
781 			ppa_fail(dev, DID_ERROR);
782 			return 0;
783 		}
784 		if (ppa_in(dev, &l, 1)) {	/* read status byte */
785 			/* Check for optional message byte */
786 			if (ppa_wait(dev) == (unsigned char) 0xf0)
787 				ppa_in(dev, &h, 1);
788 			cmd->result =
789 			    (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
790 		}
791 		return 0;	/* Finished */
792 		break;
793 
794 	default:
795 		printk(KERN_ERR "ppa: Invalid scsi phase\n");
796 	}
797 	return 0;
798 }
799 
800 static int ppa_queuecommand(struct scsi_cmnd *cmd,
801 		void (*done) (struct scsi_cmnd *))
802 {
803 	ppa_struct *dev = ppa_dev(cmd->device->host);
804 
805 	if (dev->cur_cmd) {
806 		printk(KERN_ERR "PPA: bug in ppa_queuecommand\n");
807 		return 0;
808 	}
809 	dev->failed = 0;
810 	dev->jstart = jiffies;
811 	dev->cur_cmd = cmd;
812 	cmd->scsi_done = done;
813 	cmd->result = DID_ERROR << 16;	/* default return code */
814 	cmd->SCp.phase = 0;	/* bus free */
815 
816 	schedule_delayed_work(&dev->ppa_tq, 0);
817 
818 	ppa_pb_claim(dev);
819 
820 	return 0;
821 }
822 
823 /*
824  * Apparently the disk->capacity attribute is off by 1 sector
825  * for all disk drives.  We add the one here, but it should really
826  * be done in sd.c.  Even if it gets fixed there, this will still
827  * work.
828  */
829 static int ppa_biosparam(struct scsi_device *sdev, struct block_device *dev,
830 	      sector_t capacity, int ip[])
831 {
832 	ip[0] = 0x40;
833 	ip[1] = 0x20;
834 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
835 	if (ip[2] > 1024) {
836 		ip[0] = 0xff;
837 		ip[1] = 0x3f;
838 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
839 		if (ip[2] > 1023)
840 			ip[2] = 1023;
841 	}
842 	return 0;
843 }
844 
845 static int ppa_abort(struct scsi_cmnd *cmd)
846 {
847 	ppa_struct *dev = ppa_dev(cmd->device->host);
848 	/*
849 	 * There is no method for aborting commands since Iomega
850 	 * have tied the SCSI_MESSAGE line high in the interface
851 	 */
852 
853 	switch (cmd->SCp.phase) {
854 	case 0:		/* Do not have access to parport */
855 	case 1:		/* Have not connected to interface */
856 		dev->cur_cmd = NULL;	/* Forget the problem */
857 		return SUCCESS;
858 		break;
859 	default:		/* SCSI command sent, can not abort */
860 		return FAILED;
861 		break;
862 	}
863 }
864 
865 static void ppa_reset_pulse(unsigned int base)
866 {
867 	w_dtr(base, 0x40);
868 	w_ctr(base, 0x8);
869 	udelay(30);
870 	w_ctr(base, 0xc);
871 }
872 
873 static int ppa_reset(struct scsi_cmnd *cmd)
874 {
875 	ppa_struct *dev = ppa_dev(cmd->device->host);
876 
877 	if (cmd->SCp.phase)
878 		ppa_disconnect(dev);
879 	dev->cur_cmd = NULL;	/* Forget the problem */
880 
881 	ppa_connect(dev, CONNECT_NORMAL);
882 	ppa_reset_pulse(dev->base);
883 	mdelay(1);		/* device settle delay */
884 	ppa_disconnect(dev);
885 	mdelay(1);		/* device settle delay */
886 	return SUCCESS;
887 }
888 
889 static int device_check(ppa_struct *dev)
890 {
891 	/* This routine looks for a device and then attempts to use EPP
892 	   to send a command. If all goes as planned then EPP is available. */
893 
894 	static u8 cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
895 	int loop, old_mode, status, k, ppb = dev->base;
896 	unsigned char l;
897 
898 	old_mode = dev->mode;
899 	for (loop = 0; loop < 8; loop++) {
900 		/* Attempt to use EPP for Test Unit Ready */
901 		if ((ppb & 0x0007) == 0x0000)
902 			dev->mode = PPA_EPP_32;
903 
904 second_pass:
905 		ppa_connect(dev, CONNECT_EPP_MAYBE);
906 		/* Select SCSI device */
907 		if (!ppa_select(dev, loop)) {
908 			ppa_disconnect(dev);
909 			continue;
910 		}
911 		printk(KERN_INFO "ppa: Found device at ID %i, Attempting to use %s\n",
912 		       loop, PPA_MODE_STRING[dev->mode]);
913 
914 		/* Send SCSI command */
915 		status = 1;
916 		w_ctr(ppb, 0x0c);
917 		for (l = 0; (l < 6) && (status); l++)
918 			status = ppa_out(dev, cmd, 1);
919 
920 		if (!status) {
921 			ppa_disconnect(dev);
922 			ppa_connect(dev, CONNECT_EPP_MAYBE);
923 			w_dtr(ppb, 0x40);
924 			w_ctr(ppb, 0x08);
925 			udelay(30);
926 			w_ctr(ppb, 0x0c);
927 			udelay(1000);
928 			ppa_disconnect(dev);
929 			udelay(1000);
930 			if (dev->mode == PPA_EPP_32) {
931 				dev->mode = old_mode;
932 				goto second_pass;
933 			}
934 			return -EIO;
935 		}
936 		w_ctr(ppb, 0x0c);
937 		k = 1000000;	/* 1 Second */
938 		do {
939 			l = r_str(ppb);
940 			k--;
941 			udelay(1);
942 		} while (!(l & 0x80) && (k));
943 
944 		l &= 0xf0;
945 
946 		if (l != 0xf0) {
947 			ppa_disconnect(dev);
948 			ppa_connect(dev, CONNECT_EPP_MAYBE);
949 			ppa_reset_pulse(ppb);
950 			udelay(1000);
951 			ppa_disconnect(dev);
952 			udelay(1000);
953 			if (dev->mode == PPA_EPP_32) {
954 				dev->mode = old_mode;
955 				goto second_pass;
956 			}
957 			return -EIO;
958 		}
959 		ppa_disconnect(dev);
960 		printk(KERN_INFO "ppa: Communication established with ID %i using %s\n",
961 		       loop, PPA_MODE_STRING[dev->mode]);
962 		ppa_connect(dev, CONNECT_EPP_MAYBE);
963 		ppa_reset_pulse(ppb);
964 		udelay(1000);
965 		ppa_disconnect(dev);
966 		udelay(1000);
967 		return 0;
968 	}
969 	return -ENODEV;
970 }
971 
972 static int ppa_adjust_queue(struct scsi_device *device)
973 {
974 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
975 	return 0;
976 }
977 
978 static struct scsi_host_template ppa_template = {
979 	.module			= THIS_MODULE,
980 	.proc_name		= "ppa",
981 	.proc_info		= ppa_proc_info,
982 	.name			= "Iomega VPI0 (ppa) interface",
983 	.queuecommand		= ppa_queuecommand,
984 	.eh_abort_handler	= ppa_abort,
985 	.eh_bus_reset_handler	= ppa_reset,
986 	.eh_host_reset_handler	= ppa_reset,
987 	.bios_param		= ppa_biosparam,
988 	.this_id		= -1,
989 	.sg_tablesize		= SG_ALL,
990 	.cmd_per_lun		= 1,
991 	.use_clustering		= ENABLE_CLUSTERING,
992 	.can_queue		= 1,
993 	.slave_alloc		= ppa_adjust_queue,
994 };
995 
996 /***************************************************************************
997  *                   Parallel port probing routines                        *
998  ***************************************************************************/
999 
1000 static LIST_HEAD(ppa_hosts);
1001 
1002 static int __ppa_attach(struct parport *pb)
1003 {
1004 	struct Scsi_Host *host;
1005 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1006 	DEFINE_WAIT(wait);
1007 	ppa_struct *dev;
1008 	int ports;
1009 	int modes, ppb, ppb_hi;
1010 	int err = -ENOMEM;
1011 
1012 	dev = kzalloc(sizeof(ppa_struct), GFP_KERNEL);
1013 	if (!dev)
1014 		return -ENOMEM;
1015 	dev->base = -1;
1016 	dev->mode = PPA_AUTODETECT;
1017 	dev->recon_tmo = PPA_RECON_TMO;
1018 	init_waitqueue_head(&waiting);
1019 	dev->dev = parport_register_device(pb, "ppa", NULL, ppa_wakeup,
1020 					    NULL, 0, dev);
1021 
1022 	if (!dev->dev)
1023 		goto out;
1024 
1025 	/* Claim the bus so it remembers what we do to the control
1026 	 * registers. [ CTR and ECP ]
1027 	 */
1028 	err = -EBUSY;
1029 	dev->waiting = &waiting;
1030 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1031 	if (ppa_pb_claim(dev))
1032 		schedule_timeout(3 * HZ);
1033 	if (dev->wanted) {
1034 		printk(KERN_ERR "ppa%d: failed to claim parport because "
1035 				"a pardevice is owning the port for too long "
1036 				"time!\n", pb->number);
1037 		ppa_pb_dismiss(dev);
1038 		dev->waiting = NULL;
1039 		finish_wait(&waiting, &wait);
1040 		goto out1;
1041 	}
1042 	dev->waiting = NULL;
1043 	finish_wait(&waiting, &wait);
1044 	ppb = dev->base = dev->dev->port->base;
1045 	ppb_hi = dev->dev->port->base_hi;
1046 	w_ctr(ppb, 0x0c);
1047 	modes = dev->dev->port->modes;
1048 
1049 	/* Mode detection works up the chain of speed
1050 	 * This avoids a nasty if-then-else-if-... tree
1051 	 */
1052 	dev->mode = PPA_NIBBLE;
1053 
1054 	if (modes & PARPORT_MODE_TRISTATE)
1055 		dev->mode = PPA_PS2;
1056 
1057 	if (modes & PARPORT_MODE_ECP) {
1058 		w_ecr(ppb_hi, 0x20);
1059 		dev->mode = PPA_PS2;
1060 	}
1061 	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
1062 		w_ecr(ppb_hi, 0x80);
1063 
1064 	/* Done configuration */
1065 
1066 	err = ppa_init(dev);
1067 	ppa_pb_release(dev);
1068 
1069 	if (err)
1070 		goto out1;
1071 
1072 	/* now the glue ... */
1073 	if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
1074 		ports = 3;
1075 	else
1076 		ports = 8;
1077 
1078 	INIT_DELAYED_WORK(&dev->ppa_tq, ppa_interrupt);
1079 
1080 	err = -ENOMEM;
1081 	host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
1082 	if (!host)
1083 		goto out1;
1084 	host->io_port = pb->base;
1085 	host->n_io_port = ports;
1086 	host->dma_channel = -1;
1087 	host->unique_id = pb->number;
1088 	*(ppa_struct **)&host->hostdata = dev;
1089 	dev->host = host;
1090 	list_add_tail(&dev->list, &ppa_hosts);
1091 	err = scsi_add_host(host, NULL);
1092 	if (err)
1093 		goto out2;
1094 	scsi_scan_host(host);
1095 	return 0;
1096 out2:
1097 	list_del_init(&dev->list);
1098 	scsi_host_put(host);
1099 out1:
1100 	parport_unregister_device(dev->dev);
1101 out:
1102 	kfree(dev);
1103 	return err;
1104 }
1105 
1106 static void ppa_attach(struct parport *pb)
1107 {
1108 	__ppa_attach(pb);
1109 }
1110 
1111 static void ppa_detach(struct parport *pb)
1112 {
1113 	ppa_struct *dev;
1114 	list_for_each_entry(dev, &ppa_hosts, list) {
1115 		if (dev->dev->port == pb) {
1116 			list_del_init(&dev->list);
1117 			scsi_remove_host(dev->host);
1118 			scsi_host_put(dev->host);
1119 			parport_unregister_device(dev->dev);
1120 			kfree(dev);
1121 			break;
1122 		}
1123 	}
1124 }
1125 
1126 static struct parport_driver ppa_driver = {
1127 	.name	= "ppa",
1128 	.attach	= ppa_attach,
1129 	.detach	= ppa_detach,
1130 };
1131 
1132 static int __init ppa_driver_init(void)
1133 {
1134 	printk(KERN_INFO "ppa: Version %s\n", PPA_VERSION);
1135 	return parport_register_driver(&ppa_driver);
1136 }
1137 
1138 static void __exit ppa_driver_exit(void)
1139 {
1140 	parport_unregister_driver(&ppa_driver);
1141 }
1142 
1143 module_init(ppa_driver_init);
1144 module_exit(ppa_driver_exit);
1145 MODULE_LICENSE("GPL");
1146