xref: /openbmc/linux/drivers/scsi/ppa.c (revision 4f3865fb)
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  * Current Maintainer: David Campbell (Perth, Western Australia, GMT+0800)
10  *                     campbell@torque.net
11  */
12 
13 #include <linux/config.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/blkdev.h>
18 #include <linux/parport.h>
19 #include <linux/workqueue.h>
20 #include <linux/delay.h>
21 #include <linux/jiffies.h>
22 #include <asm/io.h>
23 
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_cmnd.h>
26 #include <scsi/scsi_device.h>
27 #include <scsi/scsi_host.h>
28 
29 
30 static void ppa_reset_pulse(unsigned int base);
31 
32 typedef struct {
33 	struct pardevice *dev;	/* Parport device entry         */
34 	int base;		/* Actual port address          */
35 	int mode;		/* Transfer mode                */
36 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
37 	struct work_struct ppa_tq;	/* Polling interrupt stuff       */
38 	unsigned long jstart;	/* Jiffies at start             */
39 	unsigned long recon_tmo;	/* How many usecs to wait for reconnection (6th bit) */
40 	unsigned int failed:1;	/* Failure flag                 */
41 	unsigned wanted:1;	/* Parport sharing busy flag    */
42 	wait_queue_head_t *waiting;
43 	struct Scsi_Host *host;
44 	struct list_head list;
45 } ppa_struct;
46 
47 #include  "ppa.h"
48 
49 static inline ppa_struct *ppa_dev(struct Scsi_Host *host)
50 {
51 	return *(ppa_struct **)&host->hostdata;
52 }
53 
54 static DEFINE_SPINLOCK(arbitration_lock);
55 
56 static void got_it(ppa_struct *dev)
57 {
58 	dev->base = dev->dev->port->base;
59 	if (dev->cur_cmd)
60 		dev->cur_cmd->SCp.phase = 1;
61 	else
62 		wake_up(dev->waiting);
63 }
64 
65 static void ppa_wakeup(void *ref)
66 {
67 	ppa_struct *dev = (ppa_struct *) ref;
68 	unsigned long flags;
69 
70 	spin_lock_irqsave(&arbitration_lock, flags);
71 	if (dev->wanted) {
72 		parport_claim(dev->dev);
73 		got_it(dev);
74 		dev->wanted = 0;
75 	}
76 	spin_unlock_irqrestore(&arbitration_lock, flags);
77 	return;
78 }
79 
80 static int ppa_pb_claim(ppa_struct *dev)
81 {
82 	unsigned long flags;
83 	int res = 1;
84 	spin_lock_irqsave(&arbitration_lock, flags);
85 	if (parport_claim(dev->dev) == 0) {
86 		got_it(dev);
87 		res = 0;
88 	}
89 	dev->wanted = res;
90 	spin_unlock_irqrestore(&arbitration_lock, flags);
91 	return res;
92 }
93 
94 static void ppa_pb_dismiss(ppa_struct *dev)
95 {
96 	unsigned long flags;
97 	int wanted;
98 	spin_lock_irqsave(&arbitration_lock, flags);
99 	wanted = dev->wanted;
100 	dev->wanted = 0;
101 	spin_unlock_irqrestore(&arbitration_lock, flags);
102 	if (!wanted)
103 		parport_release(dev->dev);
104 }
105 
106 static inline void ppa_pb_release(ppa_struct *dev)
107 {
108 	parport_release(dev->dev);
109 }
110 
111 /*
112  * Start of Chipset kludges
113  */
114 
115 /* This is to give the ppa driver a way to modify the timings (and other
116  * parameters) by writing to the /proc/scsi/ppa/0 file.
117  * Very simple method really... (To simple, no error checking :( )
118  * Reason: Kernel hackers HATE having to unload and reload modules for
119  * testing...
120  * Also gives a method to use a script to obtain optimum timings (TODO)
121  */
122 
123 static inline int ppa_proc_write(ppa_struct *dev, char *buffer, int length)
124 {
125 	unsigned long x;
126 
127 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
128 		x = simple_strtoul(buffer + 5, NULL, 0);
129 		dev->mode = x;
130 		return length;
131 	}
132 	if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
133 		x = simple_strtoul(buffer + 10, NULL, 0);
134 		dev->recon_tmo = x;
135 		printk("ppa: recon_tmo set to %ld\n", x);
136 		return length;
137 	}
138 	printk("ppa /proc: invalid variable\n");
139 	return (-EINVAL);
140 }
141 
142 static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
143 {
144 	int len = 0;
145 	ppa_struct *dev = ppa_dev(host);
146 
147 	if (inout)
148 		return ppa_proc_write(dev, buffer, length);
149 
150 	len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
151 	len +=
152 	    sprintf(buffer + len, "Parport : %s\n",
153 		    dev->dev->port->name);
154 	len +=
155 	    sprintf(buffer + len, "Mode    : %s\n",
156 		    PPA_MODE_STRING[dev->mode]);
157 #if PPA_DEBUG > 0
158 	len +=
159 	    sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
160 #endif
161 
162 	/* Request for beyond end of buffer */
163 	if (offset > length)
164 		return 0;
165 
166 	*start = buffer + offset;
167 	len -= offset;
168 	if (len > length)
169 		len = length;
170 	return len;
171 }
172 
173 static int device_check(ppa_struct *dev);
174 
175 #if PPA_DEBUG > 0
176 #define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
177 	   y, __FUNCTION__, __LINE__); ppa_fail_func(x,y);
178 static inline void ppa_fail_func(ppa_struct *dev, int error_code)
179 #else
180 static inline void ppa_fail(ppa_struct *dev, int error_code)
181 #endif
182 {
183 	/* If we fail a device then we trash status / message bytes */
184 	if (dev->cur_cmd) {
185 		dev->cur_cmd->result = error_code << 16;
186 		dev->failed = 1;
187 	}
188 }
189 
190 /*
191  * Wait for the high bit to be set.
192  *
193  * In principle, this could be tied to an interrupt, but the adapter
194  * doesn't appear to be designed to support interrupts.  We spin on
195  * the 0x80 ready bit.
196  */
197 static unsigned char ppa_wait(ppa_struct *dev)
198 {
199 	int k;
200 	unsigned short ppb = dev->base;
201 	unsigned char r;
202 
203 	k = PPA_SPIN_TMO;
204 	/* Wait for bit 6 and 7 - PJC */
205 	for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
206 		udelay(1);
207 		r = r_str(ppb);
208 	}
209 
210 	/*
211 	 * return some status information.
212 	 * Semantics: 0xc0 = ZIP wants more data
213 	 *            0xd0 = ZIP wants to send more data
214 	 *            0xe0 = ZIP is expecting SCSI command data
215 	 *            0xf0 = end of transfer, ZIP is sending status
216 	 */
217 	if (k)
218 		return (r & 0xf0);
219 
220 	/* Counter expired - Time out occurred */
221 	ppa_fail(dev, DID_TIME_OUT);
222 	printk("ppa timeout in ppa_wait\n");
223 	return 0;		/* command timed out */
224 }
225 
226 /*
227  * Clear EPP Timeout Bit
228  */
229 static inline void epp_reset(unsigned short ppb)
230 {
231 	int i;
232 
233 	i = r_str(ppb);
234 	w_str(ppb, i);
235 	w_str(ppb, i & 0xfe);
236 }
237 
238 /*
239  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
240  */
241 static inline void ecp_sync(ppa_struct *dev)
242 {
243 	int i, ppb_hi = dev->dev->port->base_hi;
244 
245 	if (ppb_hi == 0)
246 		return;
247 
248 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
249 		for (i = 0; i < 100; i++) {
250 			if (r_ecr(ppb_hi) & 0x01)
251 				return;
252 			udelay(5);
253 		}
254 		printk("ppa: ECP sync failed as data still present in FIFO.\n");
255 	}
256 }
257 
258 static int ppa_byte_out(unsigned short base, const char *buffer, int len)
259 {
260 	int i;
261 
262 	for (i = len; i; i--) {
263 		w_dtr(base, *buffer++);
264 		w_ctr(base, 0xe);
265 		w_ctr(base, 0xc);
266 	}
267 	return 1;		/* All went well - we hope! */
268 }
269 
270 static int ppa_byte_in(unsigned short base, char *buffer, int len)
271 {
272 	int i;
273 
274 	for (i = len; i; i--) {
275 		*buffer++ = r_dtr(base);
276 		w_ctr(base, 0x27);
277 		w_ctr(base, 0x25);
278 	}
279 	return 1;		/* All went well - we hope! */
280 }
281 
282 static int ppa_nibble_in(unsigned short base, char *buffer, int len)
283 {
284 	for (; len; len--) {
285 		unsigned char h;
286 
287 		w_ctr(base, 0x4);
288 		h = r_str(base) & 0xf0;
289 		w_ctr(base, 0x6);
290 		*buffer++ = h | ((r_str(base) & 0xf0) >> 4);
291 	}
292 	return 1;		/* All went well - we hope! */
293 }
294 
295 static int ppa_out(ppa_struct *dev, char *buffer, int len)
296 {
297 	int r;
298 	unsigned short ppb = dev->base;
299 
300 	r = ppa_wait(dev);
301 
302 	if ((r & 0x50) != 0x40) {
303 		ppa_fail(dev, DID_ERROR);
304 		return 0;
305 	}
306 	switch (dev->mode) {
307 	case PPA_NIBBLE:
308 	case PPA_PS2:
309 		/* 8 bit output, with a loop */
310 		r = ppa_byte_out(ppb, buffer, len);
311 		break;
312 
313 	case PPA_EPP_32:
314 	case PPA_EPP_16:
315 	case PPA_EPP_8:
316 		epp_reset(ppb);
317 		w_ctr(ppb, 0x4);
318 #ifdef CONFIG_SCSI_IZIP_EPP16
319 		if (!(((long) buffer | len) & 0x01))
320 			outsw(ppb + 4, buffer, len >> 1);
321 #else
322 		if (!(((long) buffer | len) & 0x03))
323 			outsl(ppb + 4, buffer, len >> 2);
324 #endif
325 		else
326 			outsb(ppb + 4, buffer, len);
327 		w_ctr(ppb, 0xc);
328 		r = !(r_str(ppb) & 0x01);
329 		w_ctr(ppb, 0xc);
330 		ecp_sync(dev);
331 		break;
332 
333 	default:
334 		printk("PPA: bug in ppa_out()\n");
335 		r = 0;
336 	}
337 	return r;
338 }
339 
340 static int ppa_in(ppa_struct *dev, char *buffer, int len)
341 {
342 	int r;
343 	unsigned short ppb = dev->base;
344 
345 	r = ppa_wait(dev);
346 
347 	if ((r & 0x50) != 0x50) {
348 		ppa_fail(dev, DID_ERROR);
349 		return 0;
350 	}
351 	switch (dev->mode) {
352 	case PPA_NIBBLE:
353 		/* 4 bit input, with a loop */
354 		r = ppa_nibble_in(ppb, buffer, len);
355 		w_ctr(ppb, 0xc);
356 		break;
357 
358 	case PPA_PS2:
359 		/* 8 bit input, with a loop */
360 		w_ctr(ppb, 0x25);
361 		r = ppa_byte_in(ppb, buffer, len);
362 		w_ctr(ppb, 0x4);
363 		w_ctr(ppb, 0xc);
364 		break;
365 
366 	case PPA_EPP_32:
367 	case PPA_EPP_16:
368 	case PPA_EPP_8:
369 		epp_reset(ppb);
370 		w_ctr(ppb, 0x24);
371 #ifdef CONFIG_SCSI_IZIP_EPP16
372 		if (!(((long) buffer | len) & 0x01))
373 			insw(ppb + 4, buffer, len >> 1);
374 #else
375 		if (!(((long) buffer | len) & 0x03))
376 			insl(ppb + 4, buffer, len >> 2);
377 #endif
378 		else
379 			insb(ppb + 4, buffer, len);
380 		w_ctr(ppb, 0x2c);
381 		r = !(r_str(ppb) & 0x01);
382 		w_ctr(ppb, 0x2c);
383 		ecp_sync(dev);
384 		break;
385 
386 	default:
387 		printk("PPA: bug in ppa_ins()\n");
388 		r = 0;
389 		break;
390 	}
391 	return r;
392 }
393 
394 /* end of ppa_io.h */
395 static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
396 {
397 	w_dtr(ppb, b);
398 	w_ctr(ppb, 0xc);
399 	w_ctr(ppb, 0xe);
400 	w_ctr(ppb, 0xc);
401 	w_ctr(ppb, 0x4);
402 	w_ctr(ppb, 0xc);
403 }
404 
405 static void ppa_disconnect(ppa_struct *dev)
406 {
407 	unsigned short ppb = dev->base;
408 
409 	ppa_d_pulse(ppb, 0);
410 	ppa_d_pulse(ppb, 0x3c);
411 	ppa_d_pulse(ppb, 0x20);
412 	ppa_d_pulse(ppb, 0xf);
413 }
414 
415 static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
416 {
417 	w_dtr(ppb, b);
418 	w_ctr(ppb, 0x4);
419 	w_ctr(ppb, 0x6);
420 	w_ctr(ppb, 0x4);
421 	w_ctr(ppb, 0xc);
422 }
423 
424 static inline void ppa_connect(ppa_struct *dev, int flag)
425 {
426 	unsigned short ppb = dev->base;
427 
428 	ppa_c_pulse(ppb, 0);
429 	ppa_c_pulse(ppb, 0x3c);
430 	ppa_c_pulse(ppb, 0x20);
431 	if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
432 		ppa_c_pulse(ppb, 0xcf);
433 	else
434 		ppa_c_pulse(ppb, 0x8f);
435 }
436 
437 static int ppa_select(ppa_struct *dev, int target)
438 {
439 	int k;
440 	unsigned short ppb = dev->base;
441 
442 	/*
443 	 * Bit 6 (0x40) is the device selected bit.
444 	 * First we must wait till the current device goes off line...
445 	 */
446 	k = PPA_SELECT_TMO;
447 	do {
448 		k--;
449 		udelay(1);
450 	} while ((r_str(ppb) & 0x40) && (k));
451 	if (!k)
452 		return 0;
453 
454 	w_dtr(ppb, (1 << target));
455 	w_ctr(ppb, 0xe);
456 	w_ctr(ppb, 0xc);
457 	w_dtr(ppb, 0x80);	/* This is NOT the initator */
458 	w_ctr(ppb, 0x8);
459 
460 	k = PPA_SELECT_TMO;
461 	do {
462 		k--;
463 		udelay(1);
464 	}
465 	while (!(r_str(ppb) & 0x40) && (k));
466 	if (!k)
467 		return 0;
468 
469 	return 1;
470 }
471 
472 /*
473  * This is based on a trace of what the Iomega DOS 'guest' driver does.
474  * I've tried several different kinds of parallel ports with guest and
475  * coded this to react in the same ways that it does.
476  *
477  * The return value from this function is just a hint about where the
478  * handshaking failed.
479  *
480  */
481 static int ppa_init(ppa_struct *dev)
482 {
483 	int retv;
484 	unsigned short ppb = dev->base;
485 
486 	ppa_disconnect(dev);
487 	ppa_connect(dev, CONNECT_NORMAL);
488 
489 	retv = 2;		/* Failed */
490 
491 	w_ctr(ppb, 0xe);
492 	if ((r_str(ppb) & 0x08) == 0x08)
493 		retv--;
494 
495 	w_ctr(ppb, 0xc);
496 	if ((r_str(ppb) & 0x08) == 0x00)
497 		retv--;
498 
499 	if (!retv)
500 		ppa_reset_pulse(ppb);
501 	udelay(1000);		/* Allow devices to settle down */
502 	ppa_disconnect(dev);
503 	udelay(1000);		/* Another delay to allow devices to settle */
504 
505 	if (retv)
506 		return -EIO;
507 
508 	return device_check(dev);
509 }
510 
511 static inline int ppa_send_command(struct scsi_cmnd *cmd)
512 {
513 	ppa_struct *dev = ppa_dev(cmd->device->host);
514 	int k;
515 
516 	w_ctr(dev->base, 0x0c);
517 
518 	for (k = 0; k < cmd->cmd_len; k++)
519 		if (!ppa_out(dev, &cmd->cmnd[k], 1))
520 			return 0;
521 	return 1;
522 }
523 
524 /*
525  * The bulk flag enables some optimisations in the data transfer loops,
526  * it should be true for any command that transfers data in integral
527  * numbers of sectors.
528  *
529  * The driver appears to remain stable if we speed up the parallel port
530  * i/o in this function, but not elsewhere.
531  */
532 static int ppa_completion(struct scsi_cmnd *cmd)
533 {
534 	/* Return codes:
535 	 * -1     Error
536 	 *  0     Told to schedule
537 	 *  1     Finished data transfer
538 	 */
539 	ppa_struct *dev = ppa_dev(cmd->device->host);
540 	unsigned short ppb = dev->base;
541 	unsigned long start_jiffies = jiffies;
542 
543 	unsigned char r, v;
544 	int fast, bulk, status;
545 
546 	v = cmd->cmnd[0];
547 	bulk = ((v == READ_6) ||
548 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
549 
550 	/*
551 	 * We only get here if the drive is ready to comunicate,
552 	 * hence no need for a full ppa_wait.
553 	 */
554 	r = (r_str(ppb) & 0xf0);
555 
556 	while (r != (unsigned char) 0xf0) {
557 		/*
558 		 * If we have been running for more than a full timer tick
559 		 * then take a rest.
560 		 */
561 		if (time_after(jiffies, start_jiffies + 1))
562 			return 0;
563 
564 		if ((cmd->SCp.this_residual <= 0)) {
565 			ppa_fail(dev, DID_ERROR);
566 			return -1;	/* ERROR_RETURN */
567 		}
568 
569 		/* On some hardware we have SCSI disconnected (6th bit low)
570 		 * for about 100usecs. It is too expensive to wait a
571 		 * tick on every loop so we busy wait for no more than
572 		 * 500usecs to give the drive a chance first. We do not
573 		 * change things for "normal" hardware since generally
574 		 * the 6th bit is always high.
575 		 * This makes the CPU load higher on some hardware
576 		 * but otherwise we can not get more than 50K/secs
577 		 * on this problem hardware.
578 		 */
579 		if ((r & 0xc0) != 0xc0) {
580 			/* Wait for reconnection should be no more than
581 			 * jiffy/2 = 5ms = 5000 loops
582 			 */
583 			unsigned long k = dev->recon_tmo;
584 			for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
585 			     k--)
586 				udelay(1);
587 
588 			if (!k)
589 				return 0;
590 		}
591 
592 		/* determine if we should use burst I/O */
593 		fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
594 		    ? PPA_BURST_SIZE : 1;
595 
596 		if (r == (unsigned char) 0xc0)
597 			status = ppa_out(dev, cmd->SCp.ptr, fast);
598 		else
599 			status = ppa_in(dev, cmd->SCp.ptr, fast);
600 
601 		cmd->SCp.ptr += fast;
602 		cmd->SCp.this_residual -= fast;
603 
604 		if (!status) {
605 			ppa_fail(dev, DID_BUS_BUSY);
606 			return -1;	/* ERROR_RETURN */
607 		}
608 		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
609 			/* if scatter/gather, advance to the next segment */
610 			if (cmd->SCp.buffers_residual--) {
611 				cmd->SCp.buffer++;
612 				cmd->SCp.this_residual =
613 				    cmd->SCp.buffer->length;
614 				cmd->SCp.ptr =
615 				    page_address(cmd->SCp.buffer->page) +
616 				    cmd->SCp.buffer->offset;
617 			}
618 		}
619 		/* Now check to see if the drive is ready to comunicate */
620 		r = (r_str(ppb) & 0xf0);
621 		/* If not, drop back down to the scheduler and wait a timer tick */
622 		if (!(r & 0x80))
623 			return 0;
624 	}
625 	return 1;		/* FINISH_RETURN */
626 }
627 
628 /*
629  * Since the PPA itself doesn't generate interrupts, we use
630  * the scheduler's task queue to generate a stream of call-backs and
631  * complete the request when the drive is ready.
632  */
633 static void ppa_interrupt(void *data)
634 {
635 	ppa_struct *dev = (ppa_struct *) data;
636 	struct scsi_cmnd *cmd = dev->cur_cmd;
637 
638 	if (!cmd) {
639 		printk("PPA: bug in ppa_interrupt\n");
640 		return;
641 	}
642 	if (ppa_engine(dev, cmd)) {
643 		dev->ppa_tq.data = (void *) dev;
644 		schedule_delayed_work(&dev->ppa_tq, 1);
645 		return;
646 	}
647 	/* Command must of completed hence it is safe to let go... */
648 #if PPA_DEBUG > 0
649 	switch ((cmd->result >> 16) & 0xff) {
650 	case DID_OK:
651 		break;
652 	case DID_NO_CONNECT:
653 		printk("ppa: no device at SCSI ID %i\n", cmd->device->target);
654 		break;
655 	case DID_BUS_BUSY:
656 		printk("ppa: BUS BUSY - EPP timeout detected\n");
657 		break;
658 	case DID_TIME_OUT:
659 		printk("ppa: unknown timeout\n");
660 		break;
661 	case DID_ABORT:
662 		printk("ppa: told to abort\n");
663 		break;
664 	case DID_PARITY:
665 		printk("ppa: parity error (???)\n");
666 		break;
667 	case DID_ERROR:
668 		printk("ppa: internal driver error\n");
669 		break;
670 	case DID_RESET:
671 		printk("ppa: told to reset device\n");
672 		break;
673 	case DID_BAD_INTR:
674 		printk("ppa: bad interrupt (???)\n");
675 		break;
676 	default:
677 		printk("ppa: bad return code (%02x)\n",
678 		       (cmd->result >> 16) & 0xff);
679 	}
680 #endif
681 
682 	if (cmd->SCp.phase > 1)
683 		ppa_disconnect(dev);
684 
685 	ppa_pb_dismiss(dev);
686 
687 	dev->cur_cmd = NULL;
688 
689 	cmd->scsi_done(cmd);
690 }
691 
692 static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
693 {
694 	unsigned short ppb = dev->base;
695 	unsigned char l = 0, h = 0;
696 	int retv;
697 
698 	/* First check for any errors that may of occurred
699 	 * Here we check for internal errors
700 	 */
701 	if (dev->failed)
702 		return 0;
703 
704 	switch (cmd->SCp.phase) {
705 	case 0:		/* Phase 0 - Waiting for parport */
706 		if (time_after(jiffies, dev->jstart + HZ)) {
707 			/*
708 			 * We waited more than a second
709 			 * for parport to call us
710 			 */
711 			ppa_fail(dev, DID_BUS_BUSY);
712 			return 0;
713 		}
714 		return 1;	/* wait until ppa_wakeup claims parport */
715 	case 1:		/* Phase 1 - Connected */
716 		{		/* Perform a sanity check for cable unplugged */
717 			int retv = 2;	/* Failed */
718 
719 			ppa_connect(dev, CONNECT_EPP_MAYBE);
720 
721 			w_ctr(ppb, 0xe);
722 			if ((r_str(ppb) & 0x08) == 0x08)
723 				retv--;
724 
725 			w_ctr(ppb, 0xc);
726 			if ((r_str(ppb) & 0x08) == 0x00)
727 				retv--;
728 
729 			if (retv) {
730 				if (time_after(jiffies, dev->jstart + (1 * HZ))) {
731 					printk
732 					    ("ppa: Parallel port cable is unplugged!!\n");
733 					ppa_fail(dev, DID_BUS_BUSY);
734 					return 0;
735 				} else {
736 					ppa_disconnect(dev);
737 					return 1;	/* Try again in a jiffy */
738 				}
739 			}
740 			cmd->SCp.phase++;
741 		}
742 
743 	case 2:		/* Phase 2 - We are now talking to the scsi bus */
744 		if (!ppa_select(dev, scmd_id(cmd))) {
745 			ppa_fail(dev, DID_NO_CONNECT);
746 			return 0;
747 		}
748 		cmd->SCp.phase++;
749 
750 	case 3:		/* Phase 3 - Ready to accept a command */
751 		w_ctr(ppb, 0x0c);
752 		if (!(r_str(ppb) & 0x80))
753 			return 1;
754 
755 		if (!ppa_send_command(cmd))
756 			return 0;
757 		cmd->SCp.phase++;
758 
759 	case 4:		/* Phase 4 - Setup scatter/gather buffers */
760 		if (cmd->use_sg) {
761 			/* if many buffers are available, start filling the first */
762 			cmd->SCp.buffer =
763 			    (struct scatterlist *) cmd->request_buffer;
764 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
765 			cmd->SCp.ptr =
766 			    page_address(cmd->SCp.buffer->page) +
767 			    cmd->SCp.buffer->offset;
768 		} else {
769 			/* else fill the only available buffer */
770 			cmd->SCp.buffer = NULL;
771 			cmd->SCp.this_residual = cmd->request_bufflen;
772 			cmd->SCp.ptr = cmd->request_buffer;
773 		}
774 		cmd->SCp.buffers_residual = cmd->use_sg - 1;
775 		cmd->SCp.phase++;
776 
777 	case 5:		/* Phase 5 - Data transfer stage */
778 		w_ctr(ppb, 0x0c);
779 		if (!(r_str(ppb) & 0x80))
780 			return 1;
781 
782 		retv = ppa_completion(cmd);
783 		if (retv == -1)
784 			return 0;
785 		if (retv == 0)
786 			return 1;
787 		cmd->SCp.phase++;
788 
789 	case 6:		/* Phase 6 - Read status/message */
790 		cmd->result = DID_OK << 16;
791 		/* Check for data overrun */
792 		if (ppa_wait(dev) != (unsigned char) 0xf0) {
793 			ppa_fail(dev, DID_ERROR);
794 			return 0;
795 		}
796 		if (ppa_in(dev, &l, 1)) {	/* read status byte */
797 			/* Check for optional message byte */
798 			if (ppa_wait(dev) == (unsigned char) 0xf0)
799 				ppa_in(dev, &h, 1);
800 			cmd->result =
801 			    (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
802 		}
803 		return 0;	/* Finished */
804 		break;
805 
806 	default:
807 		printk("ppa: Invalid scsi phase\n");
808 	}
809 	return 0;
810 }
811 
812 static int ppa_queuecommand(struct scsi_cmnd *cmd,
813 		void (*done) (struct scsi_cmnd *))
814 {
815 	ppa_struct *dev = ppa_dev(cmd->device->host);
816 
817 	if (dev->cur_cmd) {
818 		printk("PPA: bug in ppa_queuecommand\n");
819 		return 0;
820 	}
821 	dev->failed = 0;
822 	dev->jstart = jiffies;
823 	dev->cur_cmd = cmd;
824 	cmd->scsi_done = done;
825 	cmd->result = DID_ERROR << 16;	/* default return code */
826 	cmd->SCp.phase = 0;	/* bus free */
827 
828 	dev->ppa_tq.data = dev;
829 	schedule_work(&dev->ppa_tq);
830 
831 	ppa_pb_claim(dev);
832 
833 	return 0;
834 }
835 
836 /*
837  * Apparently the disk->capacity attribute is off by 1 sector
838  * for all disk drives.  We add the one here, but it should really
839  * be done in sd.c.  Even if it gets fixed there, this will still
840  * work.
841  */
842 static int ppa_biosparam(struct scsi_device *sdev, struct block_device *dev,
843 	      sector_t capacity, int ip[])
844 {
845 	ip[0] = 0x40;
846 	ip[1] = 0x20;
847 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
848 	if (ip[2] > 1024) {
849 		ip[0] = 0xff;
850 		ip[1] = 0x3f;
851 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
852 		if (ip[2] > 1023)
853 			ip[2] = 1023;
854 	}
855 	return 0;
856 }
857 
858 static int ppa_abort(struct scsi_cmnd *cmd)
859 {
860 	ppa_struct *dev = ppa_dev(cmd->device->host);
861 	/*
862 	 * There is no method for aborting commands since Iomega
863 	 * have tied the SCSI_MESSAGE line high in the interface
864 	 */
865 
866 	switch (cmd->SCp.phase) {
867 	case 0:		/* Do not have access to parport */
868 	case 1:		/* Have not connected to interface */
869 		dev->cur_cmd = NULL;	/* Forget the problem */
870 		return SUCCESS;
871 		break;
872 	default:		/* SCSI command sent, can not abort */
873 		return FAILED;
874 		break;
875 	}
876 }
877 
878 static void ppa_reset_pulse(unsigned int base)
879 {
880 	w_dtr(base, 0x40);
881 	w_ctr(base, 0x8);
882 	udelay(30);
883 	w_ctr(base, 0xc);
884 }
885 
886 static int ppa_reset(struct scsi_cmnd *cmd)
887 {
888 	ppa_struct *dev = ppa_dev(cmd->device->host);
889 
890 	if (cmd->SCp.phase)
891 		ppa_disconnect(dev);
892 	dev->cur_cmd = NULL;	/* Forget the problem */
893 
894 	ppa_connect(dev, CONNECT_NORMAL);
895 	ppa_reset_pulse(dev->base);
896 	mdelay(1);		/* device settle delay */
897 	ppa_disconnect(dev);
898 	mdelay(1);		/* device settle delay */
899 	return SUCCESS;
900 }
901 
902 static int device_check(ppa_struct *dev)
903 {
904 	/* This routine looks for a device and then attempts to use EPP
905 	   to send a command. If all goes as planned then EPP is available. */
906 
907 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
908 	int loop, old_mode, status, k, ppb = dev->base;
909 	unsigned char l;
910 
911 	old_mode = dev->mode;
912 	for (loop = 0; loop < 8; loop++) {
913 		/* Attempt to use EPP for Test Unit Ready */
914 		if ((ppb & 0x0007) == 0x0000)
915 			dev->mode = PPA_EPP_32;
916 
917 	      second_pass:
918 		ppa_connect(dev, CONNECT_EPP_MAYBE);
919 		/* Select SCSI device */
920 		if (!ppa_select(dev, loop)) {
921 			ppa_disconnect(dev);
922 			continue;
923 		}
924 		printk("ppa: Found device at ID %i, Attempting to use %s\n",
925 		       loop, PPA_MODE_STRING[dev->mode]);
926 
927 		/* Send SCSI command */
928 		status = 1;
929 		w_ctr(ppb, 0x0c);
930 		for (l = 0; (l < 6) && (status); l++)
931 			status = ppa_out(dev, cmd, 1);
932 
933 		if (!status) {
934 			ppa_disconnect(dev);
935 			ppa_connect(dev, CONNECT_EPP_MAYBE);
936 			w_dtr(ppb, 0x40);
937 			w_ctr(ppb, 0x08);
938 			udelay(30);
939 			w_ctr(ppb, 0x0c);
940 			udelay(1000);
941 			ppa_disconnect(dev);
942 			udelay(1000);
943 			if (dev->mode == PPA_EPP_32) {
944 				dev->mode = old_mode;
945 				goto second_pass;
946 			}
947 			return -EIO;
948 		}
949 		w_ctr(ppb, 0x0c);
950 		k = 1000000;	/* 1 Second */
951 		do {
952 			l = r_str(ppb);
953 			k--;
954 			udelay(1);
955 		} while (!(l & 0x80) && (k));
956 
957 		l &= 0xf0;
958 
959 		if (l != 0xf0) {
960 			ppa_disconnect(dev);
961 			ppa_connect(dev, CONNECT_EPP_MAYBE);
962 			ppa_reset_pulse(ppb);
963 			udelay(1000);
964 			ppa_disconnect(dev);
965 			udelay(1000);
966 			if (dev->mode == PPA_EPP_32) {
967 				dev->mode = old_mode;
968 				goto second_pass;
969 			}
970 			return -EIO;
971 		}
972 		ppa_disconnect(dev);
973 		printk("ppa: Communication established with ID %i using %s\n",
974 		       loop, PPA_MODE_STRING[dev->mode]);
975 		ppa_connect(dev, CONNECT_EPP_MAYBE);
976 		ppa_reset_pulse(ppb);
977 		udelay(1000);
978 		ppa_disconnect(dev);
979 		udelay(1000);
980 		return 0;
981 	}
982 	return -ENODEV;
983 }
984 
985 static int ppa_adjust_queue(struct scsi_device *device)
986 {
987 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
988 	return 0;
989 }
990 
991 static struct scsi_host_template ppa_template = {
992 	.module			= THIS_MODULE,
993 	.proc_name		= "ppa",
994 	.proc_info		= ppa_proc_info,
995 	.name			= "Iomega VPI0 (ppa) interface",
996 	.queuecommand		= ppa_queuecommand,
997 	.eh_abort_handler	= ppa_abort,
998 	.eh_bus_reset_handler	= ppa_reset,
999 	.eh_host_reset_handler	= ppa_reset,
1000 	.bios_param		= ppa_biosparam,
1001 	.this_id		= -1,
1002 	.sg_tablesize		= SG_ALL,
1003 	.cmd_per_lun		= 1,
1004 	.use_clustering		= ENABLE_CLUSTERING,
1005 	.can_queue		= 1,
1006 	.slave_alloc		= ppa_adjust_queue,
1007 };
1008 
1009 /***************************************************************************
1010  *                   Parallel port probing routines                        *
1011  ***************************************************************************/
1012 
1013 static LIST_HEAD(ppa_hosts);
1014 
1015 static int __ppa_attach(struct parport *pb)
1016 {
1017 	struct Scsi_Host *host;
1018 	DECLARE_WAIT_QUEUE_HEAD(waiting);
1019 	DEFINE_WAIT(wait);
1020 	ppa_struct *dev;
1021 	int ports;
1022 	int modes, ppb, ppb_hi;
1023 	int err = -ENOMEM;
1024 
1025 	dev = kmalloc(sizeof(ppa_struct), GFP_KERNEL);
1026 	if (!dev)
1027 		return -ENOMEM;
1028 	memset(dev, 0, sizeof(ppa_struct));
1029 	dev->base = -1;
1030 	dev->mode = PPA_AUTODETECT;
1031 	dev->recon_tmo = PPA_RECON_TMO;
1032 	init_waitqueue_head(&waiting);
1033 	dev->dev = parport_register_device(pb, "ppa", NULL, ppa_wakeup,
1034 					    NULL, 0, dev);
1035 
1036 	if (!dev->dev)
1037 		goto out;
1038 
1039 	/* Claim the bus so it remembers what we do to the control
1040 	 * registers. [ CTR and ECP ]
1041 	 */
1042 	err = -EBUSY;
1043 	dev->waiting = &waiting;
1044 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1045 	if (ppa_pb_claim(dev))
1046 		schedule_timeout(3 * HZ);
1047 	if (dev->wanted) {
1048 		printk(KERN_ERR "ppa%d: failed to claim parport because "
1049 				"a pardevice is owning the port for too long "
1050 				"time!\n", pb->number);
1051 		ppa_pb_dismiss(dev);
1052 		dev->waiting = NULL;
1053 		finish_wait(&waiting, &wait);
1054 		goto out1;
1055 	}
1056 	dev->waiting = NULL;
1057 	finish_wait(&waiting, &wait);
1058 	ppb = dev->base = dev->dev->port->base;
1059 	ppb_hi = dev->dev->port->base_hi;
1060 	w_ctr(ppb, 0x0c);
1061 	modes = dev->dev->port->modes;
1062 
1063 	/* Mode detection works up the chain of speed
1064 	 * This avoids a nasty if-then-else-if-... tree
1065 	 */
1066 	dev->mode = PPA_NIBBLE;
1067 
1068 	if (modes & PARPORT_MODE_TRISTATE)
1069 		dev->mode = PPA_PS2;
1070 
1071 	if (modes & PARPORT_MODE_ECP) {
1072 		w_ecr(ppb_hi, 0x20);
1073 		dev->mode = PPA_PS2;
1074 	}
1075 	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
1076 		w_ecr(ppb_hi, 0x80);
1077 
1078 	/* Done configuration */
1079 
1080 	err = ppa_init(dev);
1081 	ppa_pb_release(dev);
1082 
1083 	if (err)
1084 		goto out1;
1085 
1086 	/* now the glue ... */
1087 	if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
1088 		ports = 3;
1089 	else
1090 		ports = 8;
1091 
1092 	INIT_WORK(&dev->ppa_tq, ppa_interrupt, dev);
1093 
1094 	err = -ENOMEM;
1095 	host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
1096 	if (!host)
1097 		goto out1;
1098 	host->io_port = pb->base;
1099 	host->n_io_port = ports;
1100 	host->dma_channel = -1;
1101 	host->unique_id = pb->number;
1102 	*(ppa_struct **)&host->hostdata = dev;
1103 	dev->host = host;
1104 	list_add_tail(&dev->list, &ppa_hosts);
1105 	err = scsi_add_host(host, NULL);
1106 	if (err)
1107 		goto out2;
1108 	scsi_scan_host(host);
1109 	return 0;
1110 out2:
1111 	list_del_init(&dev->list);
1112 	scsi_host_put(host);
1113 out1:
1114 	parport_unregister_device(dev->dev);
1115 out:
1116 	kfree(dev);
1117 	return err;
1118 }
1119 
1120 static void ppa_attach(struct parport *pb)
1121 {
1122 	__ppa_attach(pb);
1123 }
1124 
1125 static void ppa_detach(struct parport *pb)
1126 {
1127 	ppa_struct *dev;
1128 	list_for_each_entry(dev, &ppa_hosts, list) {
1129 		if (dev->dev->port == pb) {
1130 			list_del_init(&dev->list);
1131 			scsi_remove_host(dev->host);
1132 			scsi_host_put(dev->host);
1133 			parport_unregister_device(dev->dev);
1134 			kfree(dev);
1135 			break;
1136 		}
1137 	}
1138 }
1139 
1140 static struct parport_driver ppa_driver = {
1141 	.name	= "ppa",
1142 	.attach	= ppa_attach,
1143 	.detach	= ppa_detach,
1144 };
1145 
1146 static int __init ppa_driver_init(void)
1147 {
1148 	printk("ppa: Version %s\n", PPA_VERSION);
1149 	return parport_register_driver(&ppa_driver);
1150 }
1151 
1152 static void __exit ppa_driver_exit(void)
1153 {
1154 	parport_unregister_driver(&ppa_driver);
1155 }
1156 
1157 module_init(ppa_driver_init);
1158 module_exit(ppa_driver_exit);
1159 MODULE_LICENSE("GPL");
1160