xref: /openbmc/linux/drivers/scsi/imm.c (revision 367b8112)
1 /* imm.c   --  low level driver for the IOMEGA MatchMaker
2  * parallel port SCSI host adapter.
3  *
4  * (The IMM is the embedded controller in the ZIP Plus drive.)
5  *
6  * My unoffical company acronym list is 21 pages long:
7  *      FLA:    Four letter acronym with built in facility for
8  *              future expansion to five letters.
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 <asm/io.h>
19 
20 #include <scsi/scsi.h>
21 #include <scsi/scsi_cmnd.h>
22 #include <scsi/scsi_device.h>
23 #include <scsi/scsi_host.h>
24 
25 /* The following #define is to avoid a clash with hosts.c */
26 #define IMM_PROBE_SPP   0x0001
27 #define IMM_PROBE_PS2   0x0002
28 #define IMM_PROBE_ECR   0x0010
29 #define IMM_PROBE_EPP17 0x0100
30 #define IMM_PROBE_EPP19 0x0200
31 
32 
33 typedef struct {
34 	struct pardevice *dev;	/* Parport device entry         */
35 	int base;		/* Actual port address          */
36 	int base_hi;		/* Hi Base address for ECP-ISA chipset */
37 	int mode;		/* Transfer mode                */
38 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
39 	struct delayed_work imm_tq;	/* Polling interrupt stuff       */
40 	unsigned long jstart;	/* Jiffies at start             */
41 	unsigned failed:1;	/* Failure flag                 */
42 	unsigned dp:1;		/* Data phase present           */
43 	unsigned rd:1;		/* Read data in data phase      */
44 	unsigned wanted:1;	/* Parport sharing busy flag    */
45 	wait_queue_head_t *waiting;
46 	struct Scsi_Host *host;
47 	struct list_head list;
48 } imm_struct;
49 
50 static void imm_reset_pulse(unsigned int base);
51 static int device_check(imm_struct *dev);
52 
53 #include "imm.h"
54 
55 static inline imm_struct *imm_dev(struct Scsi_Host *host)
56 {
57 	return *(imm_struct **)&host->hostdata;
58 }
59 
60 static DEFINE_SPINLOCK(arbitration_lock);
61 
62 static void got_it(imm_struct *dev)
63 {
64 	dev->base = dev->dev->port->base;
65 	if (dev->cur_cmd)
66 		dev->cur_cmd->SCp.phase = 1;
67 	else
68 		wake_up(dev->waiting);
69 }
70 
71 static void imm_wakeup(void *ref)
72 {
73 	imm_struct *dev = (imm_struct *) ref;
74 	unsigned long flags;
75 
76 	spin_lock_irqsave(&arbitration_lock, flags);
77 	if (dev->wanted) {
78 		parport_claim(dev->dev);
79 		got_it(dev);
80 		dev->wanted = 0;
81 	}
82 	spin_unlock_irqrestore(&arbitration_lock, flags);
83 }
84 
85 static int imm_pb_claim(imm_struct *dev)
86 {
87 	unsigned long flags;
88 	int res = 1;
89 	spin_lock_irqsave(&arbitration_lock, flags);
90 	if (parport_claim(dev->dev) == 0) {
91 		got_it(dev);
92 		res = 0;
93 	}
94 	dev->wanted = res;
95 	spin_unlock_irqrestore(&arbitration_lock, flags);
96 	return res;
97 }
98 
99 static void imm_pb_dismiss(imm_struct *dev)
100 {
101 	unsigned long flags;
102 	int wanted;
103 	spin_lock_irqsave(&arbitration_lock, flags);
104 	wanted = dev->wanted;
105 	dev->wanted = 0;
106 	spin_unlock_irqrestore(&arbitration_lock, flags);
107 	if (!wanted)
108 		parport_release(dev->dev);
109 }
110 
111 static inline void imm_pb_release(imm_struct *dev)
112 {
113 	parport_release(dev->dev);
114 }
115 
116 /* This is to give the imm driver a way to modify the timings (and other
117  * parameters) by writing to the /proc/scsi/imm/0 file.
118  * Very simple method really... (Too simple, no error checking :( )
119  * Reason: Kernel hackers HATE having to unload and reload modules for
120  * testing...
121  * Also gives a method to use a script to obtain optimum timings (TODO)
122  */
123 static inline int imm_proc_write(imm_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 	printk("imm /proc: invalid variable\n");
133 	return (-EINVAL);
134 }
135 
136 static int imm_proc_info(struct Scsi_Host *host, char *buffer, char **start,
137 			off_t offset, int length, int inout)
138 {
139 	imm_struct *dev = imm_dev(host);
140 	int len = 0;
141 
142 	if (inout)
143 		return imm_proc_write(dev, buffer, length);
144 
145 	len += sprintf(buffer + len, "Version : %s\n", IMM_VERSION);
146 	len +=
147 	    sprintf(buffer + len, "Parport : %s\n",
148 		    dev->dev->port->name);
149 	len +=
150 	    sprintf(buffer + len, "Mode    : %s\n",
151 		    IMM_MODE_STRING[dev->mode]);
152 
153 	/* Request for beyond end of buffer */
154 	if (offset > len)
155 		return 0;
156 
157 	*start = buffer + offset;
158 	len -= offset;
159 	if (len > length)
160 		len = length;
161 	return len;
162 }
163 
164 #if IMM_DEBUG > 0
165 #define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
166 	   y, __func__, __LINE__); imm_fail_func(x,y);
167 static inline void
168 imm_fail_func(imm_struct *dev, int error_code)
169 #else
170 static inline void
171 imm_fail(imm_struct *dev, int error_code)
172 #endif
173 {
174 	/* If we fail a device then we trash status / message bytes */
175 	if (dev->cur_cmd) {
176 		dev->cur_cmd->result = error_code << 16;
177 		dev->failed = 1;
178 	}
179 }
180 
181 /*
182  * Wait for the high bit to be set.
183  *
184  * In principle, this could be tied to an interrupt, but the adapter
185  * doesn't appear to be designed to support interrupts.  We spin on
186  * the 0x80 ready bit.
187  */
188 static unsigned char imm_wait(imm_struct *dev)
189 {
190 	int k;
191 	unsigned short ppb = dev->base;
192 	unsigned char r;
193 
194 	w_ctr(ppb, 0x0c);
195 
196 	k = IMM_SPIN_TMO;
197 	do {
198 		r = r_str(ppb);
199 		k--;
200 		udelay(1);
201 	}
202 	while (!(r & 0x80) && (k));
203 
204 	/*
205 	 * STR register (LPT base+1) to SCSI mapping:
206 	 *
207 	 * STR      imm     imm
208 	 * ===================================
209 	 * 0x80     S_REQ   S_REQ
210 	 * 0x40     !S_BSY  (????)
211 	 * 0x20     !S_CD   !S_CD
212 	 * 0x10     !S_IO   !S_IO
213 	 * 0x08     (????)  !S_BSY
214 	 *
215 	 * imm      imm     meaning
216 	 * ==================================
217 	 * 0xf0     0xb8    Bit mask
218 	 * 0xc0     0x88    ZIP wants more data
219 	 * 0xd0     0x98    ZIP wants to send more data
220 	 * 0xe0     0xa8    ZIP is expecting SCSI command data
221 	 * 0xf0     0xb8    end of transfer, ZIP is sending status
222 	 */
223 	w_ctr(ppb, 0x04);
224 	if (k)
225 		return (r & 0xb8);
226 
227 	/* Counter expired - Time out occurred */
228 	imm_fail(dev, DID_TIME_OUT);
229 	printk("imm timeout in imm_wait\n");
230 	return 0;		/* command timed out */
231 }
232 
233 static int imm_negotiate(imm_struct * tmp)
234 {
235 	/*
236 	 * The following is supposedly the IEEE 1284-1994 negotiate
237 	 * sequence. I have yet to obtain a copy of the above standard
238 	 * so this is a bit of a guess...
239 	 *
240 	 * A fair chunk of this is based on the Linux parport implementation
241 	 * of IEEE 1284.
242 	 *
243 	 * Return 0 if data available
244 	 *        1 if no data available
245 	 */
246 
247 	unsigned short base = tmp->base;
248 	unsigned char a, mode;
249 
250 	switch (tmp->mode) {
251 	case IMM_NIBBLE:
252 		mode = 0x00;
253 		break;
254 	case IMM_PS2:
255 		mode = 0x01;
256 		break;
257 	default:
258 		return 0;
259 	}
260 
261 	w_ctr(base, 0x04);
262 	udelay(5);
263 	w_dtr(base, mode);
264 	udelay(100);
265 	w_ctr(base, 0x06);
266 	udelay(5);
267 	a = (r_str(base) & 0x20) ? 0 : 1;
268 	udelay(5);
269 	w_ctr(base, 0x07);
270 	udelay(5);
271 	w_ctr(base, 0x06);
272 
273 	if (a) {
274 		printk
275 		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
276 		imm_fail(tmp, DID_ERROR);
277 	}
278 	return a;
279 }
280 
281 /*
282  * Clear EPP timeout bit.
283  */
284 static inline void epp_reset(unsigned short ppb)
285 {
286 	int i;
287 
288 	i = r_str(ppb);
289 	w_str(ppb, i);
290 	w_str(ppb, i & 0xfe);
291 }
292 
293 /*
294  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
295  */
296 static inline void ecp_sync(imm_struct *dev)
297 {
298 	int i, ppb_hi = dev->base_hi;
299 
300 	if (ppb_hi == 0)
301 		return;
302 
303 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
304 		for (i = 0; i < 100; i++) {
305 			if (r_ecr(ppb_hi) & 0x01)
306 				return;
307 			udelay(5);
308 		}
309 		printk("imm: ECP sync failed as data still present in FIFO.\n");
310 	}
311 }
312 
313 static int imm_byte_out(unsigned short base, const char *buffer, int len)
314 {
315 	int i;
316 
317 	w_ctr(base, 0x4);	/* apparently a sane mode */
318 	for (i = len >> 1; i; i--) {
319 		w_dtr(base, *buffer++);
320 		w_ctr(base, 0x5);	/* Drop STROBE low */
321 		w_dtr(base, *buffer++);
322 		w_ctr(base, 0x0);	/* STROBE high + INIT low */
323 	}
324 	w_ctr(base, 0x4);	/* apparently a sane mode */
325 	return 1;		/* All went well - we hope! */
326 }
327 
328 static int imm_nibble_in(unsigned short base, char *buffer, int len)
329 {
330 	unsigned char l;
331 	int i;
332 
333 	/*
334 	 * The following is based on documented timing signals
335 	 */
336 	w_ctr(base, 0x4);
337 	for (i = len; i; i--) {
338 		w_ctr(base, 0x6);
339 		l = (r_str(base) & 0xf0) >> 4;
340 		w_ctr(base, 0x5);
341 		*buffer++ = (r_str(base) & 0xf0) | l;
342 		w_ctr(base, 0x4);
343 	}
344 	return 1;		/* All went well - we hope! */
345 }
346 
347 static int imm_byte_in(unsigned short base, char *buffer, int len)
348 {
349 	int i;
350 
351 	/*
352 	 * The following is based on documented timing signals
353 	 */
354 	w_ctr(base, 0x4);
355 	for (i = len; i; i--) {
356 		w_ctr(base, 0x26);
357 		*buffer++ = r_dtr(base);
358 		w_ctr(base, 0x25);
359 	}
360 	return 1;		/* All went well - we hope! */
361 }
362 
363 static int imm_out(imm_struct *dev, char *buffer, int len)
364 {
365 	unsigned short ppb = dev->base;
366 	int r = imm_wait(dev);
367 
368 	/*
369 	 * Make sure that:
370 	 * a) the SCSI bus is BUSY (device still listening)
371 	 * b) the device is listening
372 	 */
373 	if ((r & 0x18) != 0x08) {
374 		imm_fail(dev, DID_ERROR);
375 		printk("IMM: returned SCSI status %2x\n", r);
376 		return 0;
377 	}
378 	switch (dev->mode) {
379 	case IMM_EPP_32:
380 	case IMM_EPP_16:
381 	case IMM_EPP_8:
382 		epp_reset(ppb);
383 		w_ctr(ppb, 0x4);
384 #ifdef CONFIG_SCSI_IZIP_EPP16
385 		if (!(((long) buffer | len) & 0x01))
386 			outsw(ppb + 4, buffer, len >> 1);
387 #else
388 		if (!(((long) buffer | len) & 0x03))
389 			outsl(ppb + 4, buffer, len >> 2);
390 #endif
391 		else
392 			outsb(ppb + 4, buffer, len);
393 		w_ctr(ppb, 0xc);
394 		r = !(r_str(ppb) & 0x01);
395 		w_ctr(ppb, 0xc);
396 		ecp_sync(dev);
397 		break;
398 
399 	case IMM_NIBBLE:
400 	case IMM_PS2:
401 		/* 8 bit output, with a loop */
402 		r = imm_byte_out(ppb, buffer, len);
403 		break;
404 
405 	default:
406 		printk("IMM: bug in imm_out()\n");
407 		r = 0;
408 	}
409 	return r;
410 }
411 
412 static int imm_in(imm_struct *dev, char *buffer, int len)
413 {
414 	unsigned short ppb = dev->base;
415 	int r = imm_wait(dev);
416 
417 	/*
418 	 * Make sure that:
419 	 * a) the SCSI bus is BUSY (device still listening)
420 	 * b) the device is sending data
421 	 */
422 	if ((r & 0x18) != 0x18) {
423 		imm_fail(dev, DID_ERROR);
424 		return 0;
425 	}
426 	switch (dev->mode) {
427 	case IMM_NIBBLE:
428 		/* 4 bit input, with a loop */
429 		r = imm_nibble_in(ppb, buffer, len);
430 		w_ctr(ppb, 0xc);
431 		break;
432 
433 	case IMM_PS2:
434 		/* 8 bit input, with a loop */
435 		r = imm_byte_in(ppb, buffer, len);
436 		w_ctr(ppb, 0xc);
437 		break;
438 
439 	case IMM_EPP_32:
440 	case IMM_EPP_16:
441 	case IMM_EPP_8:
442 		epp_reset(ppb);
443 		w_ctr(ppb, 0x24);
444 #ifdef CONFIG_SCSI_IZIP_EPP16
445 		if (!(((long) buffer | len) & 0x01))
446 			insw(ppb + 4, buffer, len >> 1);
447 #else
448 		if (!(((long) buffer | len) & 0x03))
449 			insl(ppb + 4, buffer, len >> 2);
450 #endif
451 		else
452 			insb(ppb + 4, buffer, len);
453 		w_ctr(ppb, 0x2c);
454 		r = !(r_str(ppb) & 0x01);
455 		w_ctr(ppb, 0x2c);
456 		ecp_sync(dev);
457 		break;
458 
459 	default:
460 		printk("IMM: bug in imm_ins()\n");
461 		r = 0;
462 		break;
463 	}
464 	return r;
465 }
466 
467 static int imm_cpp(unsigned short ppb, unsigned char b)
468 {
469 	/*
470 	 * Comments on udelay values refer to the
471 	 * Command Packet Protocol (CPP) timing diagram.
472 	 */
473 
474 	unsigned char s1, s2, s3;
475 	w_ctr(ppb, 0x0c);
476 	udelay(2);		/* 1 usec - infinite */
477 	w_dtr(ppb, 0xaa);
478 	udelay(10);		/* 7 usec - infinite */
479 	w_dtr(ppb, 0x55);
480 	udelay(10);		/* 7 usec - infinite */
481 	w_dtr(ppb, 0x00);
482 	udelay(10);		/* 7 usec - infinite */
483 	w_dtr(ppb, 0xff);
484 	udelay(10);		/* 7 usec - infinite */
485 	s1 = r_str(ppb) & 0xb8;
486 	w_dtr(ppb, 0x87);
487 	udelay(10);		/* 7 usec - infinite */
488 	s2 = r_str(ppb) & 0xb8;
489 	w_dtr(ppb, 0x78);
490 	udelay(10);		/* 7 usec - infinite */
491 	s3 = r_str(ppb) & 0x38;
492 	/*
493 	 * Values for b are:
494 	 * 0000 00aa    Assign address aa to current device
495 	 * 0010 00aa    Select device aa in EPP Winbond mode
496 	 * 0010 10aa    Select device aa in EPP mode
497 	 * 0011 xxxx    Deselect all devices
498 	 * 0110 00aa    Test device aa
499 	 * 1101 00aa    Select device aa in ECP mode
500 	 * 1110 00aa    Select device aa in Compatible mode
501 	 */
502 	w_dtr(ppb, b);
503 	udelay(2);		/* 1 usec - infinite */
504 	w_ctr(ppb, 0x0c);
505 	udelay(10);		/* 7 usec - infinite */
506 	w_ctr(ppb, 0x0d);
507 	udelay(2);		/* 1 usec - infinite */
508 	w_ctr(ppb, 0x0c);
509 	udelay(10);		/* 7 usec - infinite */
510 	w_dtr(ppb, 0xff);
511 	udelay(10);		/* 7 usec - infinite */
512 
513 	/*
514 	 * The following table is electrical pin values.
515 	 * (BSY is inverted at the CTR register)
516 	 *
517 	 *       BSY  ACK  POut SEL  Fault
518 	 * S1    0    X    1    1    1
519 	 * S2    1    X    0    1    1
520 	 * S3    L    X    1    1    S
521 	 *
522 	 * L => Last device in chain
523 	 * S => Selected
524 	 *
525 	 * Observered values for S1,S2,S3 are:
526 	 * Disconnect => f8/58/78
527 	 * Connect    => f8/58/70
528 	 */
529 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
530 		return 1;	/* Connected */
531 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
532 		return 0;	/* Disconnected */
533 
534 	return -1;		/* No device present */
535 }
536 
537 static inline int imm_connect(imm_struct *dev, int flag)
538 {
539 	unsigned short ppb = dev->base;
540 
541 	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
542 	imm_cpp(ppb, 0x30);	/* Disconnect all devices */
543 
544 	if ((dev->mode == IMM_EPP_8) ||
545 	    (dev->mode == IMM_EPP_16) ||
546 	    (dev->mode == IMM_EPP_32))
547 		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
548 	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
549 }
550 
551 static void imm_disconnect(imm_struct *dev)
552 {
553 	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
554 }
555 
556 static int imm_select(imm_struct *dev, int target)
557 {
558 	int k;
559 	unsigned short ppb = dev->base;
560 
561 	/*
562 	 * Firstly we want to make sure there is nothing
563 	 * holding onto the SCSI bus.
564 	 */
565 	w_ctr(ppb, 0xc);
566 
567 	k = IMM_SELECT_TMO;
568 	do {
569 		k--;
570 	} while ((r_str(ppb) & 0x08) && (k));
571 
572 	if (!k)
573 		return 0;
574 
575 	/*
576 	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
577 	 */
578 	w_ctr(ppb, 0x4);
579 	w_dtr(ppb, 0x80 | (1 << target));
580 	udelay(1);
581 
582 	/*
583 	 * Deassert SELIN first followed by STROBE
584 	 */
585 	w_ctr(ppb, 0xc);
586 	w_ctr(ppb, 0xd);
587 
588 	/*
589 	 * ACK should drop low while SELIN is deasserted.
590 	 * FAULT should drop low when the SCSI device latches the bus.
591 	 */
592 	k = IMM_SELECT_TMO;
593 	do {
594 		k--;
595 	}
596 	while (!(r_str(ppb) & 0x08) && (k));
597 
598 	/*
599 	 * Place the interface back into a sane state (status mode)
600 	 */
601 	w_ctr(ppb, 0xc);
602 	return (k) ? 1 : 0;
603 }
604 
605 static int imm_init(imm_struct *dev)
606 {
607 	if (imm_connect(dev, 0) != 1)
608 		return -EIO;
609 	imm_reset_pulse(dev->base);
610 	mdelay(1);	/* Delay to allow devices to settle */
611 	imm_disconnect(dev);
612 	mdelay(1);	/* Another delay to allow devices to settle */
613 	return device_check(dev);
614 }
615 
616 static inline int imm_send_command(struct scsi_cmnd *cmd)
617 {
618 	imm_struct *dev = imm_dev(cmd->device->host);
619 	int k;
620 
621 	/* NOTE: IMM uses byte pairs */
622 	for (k = 0; k < cmd->cmd_len; k += 2)
623 		if (!imm_out(dev, &cmd->cmnd[k], 2))
624 			return 0;
625 	return 1;
626 }
627 
628 /*
629  * The bulk flag enables some optimisations in the data transfer loops,
630  * it should be true for any command that transfers data in integral
631  * numbers of sectors.
632  *
633  * The driver appears to remain stable if we speed up the parallel port
634  * i/o in this function, but not elsewhere.
635  */
636 static int imm_completion(struct scsi_cmnd *cmd)
637 {
638 	/* Return codes:
639 	 * -1     Error
640 	 *  0     Told to schedule
641 	 *  1     Finished data transfer
642 	 */
643 	imm_struct *dev = imm_dev(cmd->device->host);
644 	unsigned short ppb = dev->base;
645 	unsigned long start_jiffies = jiffies;
646 
647 	unsigned char r, v;
648 	int fast, bulk, status;
649 
650 	v = cmd->cmnd[0];
651 	bulk = ((v == READ_6) ||
652 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
653 
654 	/*
655 	 * We only get here if the drive is ready to comunicate,
656 	 * hence no need for a full imm_wait.
657 	 */
658 	w_ctr(ppb, 0x0c);
659 	r = (r_str(ppb) & 0xb8);
660 
661 	/*
662 	 * while (device is not ready to send status byte)
663 	 *     loop;
664 	 */
665 	while (r != (unsigned char) 0xb8) {
666 		/*
667 		 * If we have been running for more than a full timer tick
668 		 * then take a rest.
669 		 */
670 		if (time_after(jiffies, start_jiffies + 1))
671 			return 0;
672 
673 		/*
674 		 * FAIL if:
675 		 * a) Drive status is screwy (!ready && !present)
676 		 * b) Drive is requesting/sending more data than expected
677 		 */
678 		if (((r & 0x88) != 0x88) || (cmd->SCp.this_residual <= 0)) {
679 			imm_fail(dev, DID_ERROR);
680 			return -1;	/* ERROR_RETURN */
681 		}
682 		/* determine if we should use burst I/O */
683 		if (dev->rd == 0) {
684 			fast = (bulk
685 				&& (cmd->SCp.this_residual >=
686 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 2;
687 			status = imm_out(dev, cmd->SCp.ptr, fast);
688 		} else {
689 			fast = (bulk
690 				&& (cmd->SCp.this_residual >=
691 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 1;
692 			status = imm_in(dev, cmd->SCp.ptr, fast);
693 		}
694 
695 		cmd->SCp.ptr += fast;
696 		cmd->SCp.this_residual -= fast;
697 
698 		if (!status) {
699 			imm_fail(dev, DID_BUS_BUSY);
700 			return -1;	/* ERROR_RETURN */
701 		}
702 		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
703 			/* if scatter/gather, advance to the next segment */
704 			if (cmd->SCp.buffers_residual--) {
705 				cmd->SCp.buffer++;
706 				cmd->SCp.this_residual =
707 				    cmd->SCp.buffer->length;
708 				cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
709 
710 				/*
711 				 * Make sure that we transfer even number of bytes
712 				 * otherwise it makes imm_byte_out() messy.
713 				 */
714 				if (cmd->SCp.this_residual & 0x01)
715 					cmd->SCp.this_residual++;
716 			}
717 		}
718 		/* Now check to see if the drive is ready to comunicate */
719 		w_ctr(ppb, 0x0c);
720 		r = (r_str(ppb) & 0xb8);
721 
722 		/* If not, drop back down to the scheduler and wait a timer tick */
723 		if (!(r & 0x80))
724 			return 0;
725 	}
726 	return 1;		/* FINISH_RETURN */
727 }
728 
729 /*
730  * Since the IMM itself doesn't generate interrupts, we use
731  * the scheduler's task queue to generate a stream of call-backs and
732  * complete the request when the drive is ready.
733  */
734 static void imm_interrupt(struct work_struct *work)
735 {
736 	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
737 	struct scsi_cmnd *cmd = dev->cur_cmd;
738 	struct Scsi_Host *host = cmd->device->host;
739 	unsigned long flags;
740 
741 	if (imm_engine(dev, cmd)) {
742 		schedule_delayed_work(&dev->imm_tq, 1);
743 		return;
744 	}
745 	/* Command must of completed hence it is safe to let go... */
746 #if IMM_DEBUG > 0
747 	switch ((cmd->result >> 16) & 0xff) {
748 	case DID_OK:
749 		break;
750 	case DID_NO_CONNECT:
751 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
752 		break;
753 	case DID_BUS_BUSY:
754 		printk("imm: BUS BUSY - EPP timeout detected\n");
755 		break;
756 	case DID_TIME_OUT:
757 		printk("imm: unknown timeout\n");
758 		break;
759 	case DID_ABORT:
760 		printk("imm: told to abort\n");
761 		break;
762 	case DID_PARITY:
763 		printk("imm: parity error (???)\n");
764 		break;
765 	case DID_ERROR:
766 		printk("imm: internal driver error\n");
767 		break;
768 	case DID_RESET:
769 		printk("imm: told to reset device\n");
770 		break;
771 	case DID_BAD_INTR:
772 		printk("imm: bad interrupt (???)\n");
773 		break;
774 	default:
775 		printk("imm: bad return code (%02x)\n",
776 		       (cmd->result >> 16) & 0xff);
777 	}
778 #endif
779 
780 	if (cmd->SCp.phase > 1)
781 		imm_disconnect(dev);
782 
783 	imm_pb_dismiss(dev);
784 
785 	spin_lock_irqsave(host->host_lock, flags);
786 	dev->cur_cmd = NULL;
787 	cmd->scsi_done(cmd);
788 	spin_unlock_irqrestore(host->host_lock, flags);
789 	return;
790 }
791 
792 static int imm_engine(imm_struct *dev, struct scsi_cmnd *cmd)
793 {
794 	unsigned short ppb = dev->base;
795 	unsigned char l = 0, h = 0;
796 	int retv, x;
797 
798 	/* First check for any errors that may have occurred
799 	 * Here we check for internal errors
800 	 */
801 	if (dev->failed)
802 		return 0;
803 
804 	switch (cmd->SCp.phase) {
805 	case 0:		/* Phase 0 - Waiting for parport */
806 		if (time_after(jiffies, dev->jstart + HZ)) {
807 			/*
808 			 * We waited more than a second
809 			 * for parport to call us
810 			 */
811 			imm_fail(dev, DID_BUS_BUSY);
812 			return 0;
813 		}
814 		return 1;	/* wait until imm_wakeup claims parport */
815 		/* Phase 1 - Connected */
816 	case 1:
817 		imm_connect(dev, CONNECT_EPP_MAYBE);
818 		cmd->SCp.phase++;
819 
820 		/* Phase 2 - We are now talking to the scsi bus */
821 	case 2:
822 		if (!imm_select(dev, scmd_id(cmd))) {
823 			imm_fail(dev, DID_NO_CONNECT);
824 			return 0;
825 		}
826 		cmd->SCp.phase++;
827 
828 		/* Phase 3 - Ready to accept a command */
829 	case 3:
830 		w_ctr(ppb, 0x0c);
831 		if (!(r_str(ppb) & 0x80))
832 			return 1;
833 
834 		if (!imm_send_command(cmd))
835 			return 0;
836 		cmd->SCp.phase++;
837 
838 		/* Phase 4 - Setup scatter/gather buffers */
839 	case 4:
840 		if (scsi_bufflen(cmd)) {
841 			cmd->SCp.buffer = scsi_sglist(cmd);
842 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
843 			cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
844 		} else {
845 			cmd->SCp.buffer = NULL;
846 			cmd->SCp.this_residual = 0;
847 			cmd->SCp.ptr = NULL;
848 		}
849 		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
850 		cmd->SCp.phase++;
851 		if (cmd->SCp.this_residual & 0x01)
852 			cmd->SCp.this_residual++;
853 		/* Phase 5 - Pre-Data transfer stage */
854 	case 5:
855 		/* Spin lock for BUSY */
856 		w_ctr(ppb, 0x0c);
857 		if (!(r_str(ppb) & 0x80))
858 			return 1;
859 
860 		/* Require negotiation for read requests */
861 		x = (r_str(ppb) & 0xb8);
862 		dev->rd = (x & 0x10) ? 1 : 0;
863 		dev->dp = (x & 0x20) ? 0 : 1;
864 
865 		if ((dev->dp) && (dev->rd))
866 			if (imm_negotiate(dev))
867 				return 0;
868 		cmd->SCp.phase++;
869 
870 		/* Phase 6 - Data transfer stage */
871 	case 6:
872 		/* Spin lock for BUSY */
873 		w_ctr(ppb, 0x0c);
874 		if (!(r_str(ppb) & 0x80))
875 			return 1;
876 
877 		if (dev->dp) {
878 			retv = imm_completion(cmd);
879 			if (retv == -1)
880 				return 0;
881 			if (retv == 0)
882 				return 1;
883 		}
884 		cmd->SCp.phase++;
885 
886 		/* Phase 7 - Post data transfer stage */
887 	case 7:
888 		if ((dev->dp) && (dev->rd)) {
889 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
890 				w_ctr(ppb, 0x4);
891 				w_ctr(ppb, 0xc);
892 				w_ctr(ppb, 0xe);
893 				w_ctr(ppb, 0x4);
894 			}
895 		}
896 		cmd->SCp.phase++;
897 
898 		/* Phase 8 - Read status/message */
899 	case 8:
900 		/* Check for data overrun */
901 		if (imm_wait(dev) != (unsigned char) 0xb8) {
902 			imm_fail(dev, DID_ERROR);
903 			return 0;
904 		}
905 		if (imm_negotiate(dev))
906 			return 0;
907 		if (imm_in(dev, &l, 1)) {	/* read status byte */
908 			/* Check for optional message byte */
909 			if (imm_wait(dev) == (unsigned char) 0xb8)
910 				imm_in(dev, &h, 1);
911 			cmd->result = (DID_OK << 16) + (l & STATUS_MASK);
912 		}
913 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
914 			w_ctr(ppb, 0x4);
915 			w_ctr(ppb, 0xc);
916 			w_ctr(ppb, 0xe);
917 			w_ctr(ppb, 0x4);
918 		}
919 		return 0;	/* Finished */
920 		break;
921 
922 	default:
923 		printk("imm: Invalid scsi phase\n");
924 	}
925 	return 0;
926 }
927 
928 static int imm_queuecommand(struct scsi_cmnd *cmd,
929 		void (*done)(struct scsi_cmnd *))
930 {
931 	imm_struct *dev = imm_dev(cmd->device->host);
932 
933 	if (dev->cur_cmd) {
934 		printk("IMM: bug in imm_queuecommand\n");
935 		return 0;
936 	}
937 	dev->failed = 0;
938 	dev->jstart = jiffies;
939 	dev->cur_cmd = cmd;
940 	cmd->scsi_done = done;
941 	cmd->result = DID_ERROR << 16;	/* default return code */
942 	cmd->SCp.phase = 0;	/* bus free */
943 
944 	schedule_delayed_work(&dev->imm_tq, 0);
945 
946 	imm_pb_claim(dev);
947 
948 	return 0;
949 }
950 
951 /*
952  * Apparently the disk->capacity attribute is off by 1 sector
953  * for all disk drives.  We add the one here, but it should really
954  * be done in sd.c.  Even if it gets fixed there, this will still
955  * work.
956  */
957 static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
958 			 sector_t capacity, int ip[])
959 {
960 	ip[0] = 0x40;
961 	ip[1] = 0x20;
962 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
963 	if (ip[2] > 1024) {
964 		ip[0] = 0xff;
965 		ip[1] = 0x3f;
966 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
967 	}
968 	return 0;
969 }
970 
971 static int imm_abort(struct scsi_cmnd *cmd)
972 {
973 	imm_struct *dev = imm_dev(cmd->device->host);
974 	/*
975 	 * There is no method for aborting commands since Iomega
976 	 * have tied the SCSI_MESSAGE line high in the interface
977 	 */
978 
979 	switch (cmd->SCp.phase) {
980 	case 0:		/* Do not have access to parport */
981 	case 1:		/* Have not connected to interface */
982 		dev->cur_cmd = NULL;	/* Forget the problem */
983 		return SUCCESS;
984 		break;
985 	default:		/* SCSI command sent, can not abort */
986 		return FAILED;
987 		break;
988 	}
989 }
990 
991 static void imm_reset_pulse(unsigned int base)
992 {
993 	w_ctr(base, 0x04);
994 	w_dtr(base, 0x40);
995 	udelay(1);
996 	w_ctr(base, 0x0c);
997 	w_ctr(base, 0x0d);
998 	udelay(50);
999 	w_ctr(base, 0x0c);
1000 	w_ctr(base, 0x04);
1001 }
1002 
1003 static int imm_reset(struct scsi_cmnd *cmd)
1004 {
1005 	imm_struct *dev = imm_dev(cmd->device->host);
1006 
1007 	if (cmd->SCp.phase)
1008 		imm_disconnect(dev);
1009 	dev->cur_cmd = NULL;	/* Forget the problem */
1010 
1011 	imm_connect(dev, CONNECT_NORMAL);
1012 	imm_reset_pulse(dev->base);
1013 	mdelay(1);		/* device settle delay */
1014 	imm_disconnect(dev);
1015 	mdelay(1);		/* device settle delay */
1016 	return SUCCESS;
1017 }
1018 
1019 static int device_check(imm_struct *dev)
1020 {
1021 	/* This routine looks for a device and then attempts to use EPP
1022 	   to send a command. If all goes as planned then EPP is available. */
1023 
1024 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1025 	int loop, old_mode, status, k, ppb = dev->base;
1026 	unsigned char l;
1027 
1028 	old_mode = dev->mode;
1029 	for (loop = 0; loop < 8; loop++) {
1030 		/* Attempt to use EPP for Test Unit Ready */
1031 		if ((ppb & 0x0007) == 0x0000)
1032 			dev->mode = IMM_EPP_32;
1033 
1034 	      second_pass:
1035 		imm_connect(dev, CONNECT_EPP_MAYBE);
1036 		/* Select SCSI device */
1037 		if (!imm_select(dev, loop)) {
1038 			imm_disconnect(dev);
1039 			continue;
1040 		}
1041 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1042 		       loop, IMM_MODE_STRING[dev->mode]);
1043 
1044 		/* Send SCSI command */
1045 		status = 1;
1046 		w_ctr(ppb, 0x0c);
1047 		for (l = 0; (l < 3) && (status); l++)
1048 			status = imm_out(dev, &cmd[l << 1], 2);
1049 
1050 		if (!status) {
1051 			imm_disconnect(dev);
1052 			imm_connect(dev, CONNECT_EPP_MAYBE);
1053 			imm_reset_pulse(dev->base);
1054 			udelay(1000);
1055 			imm_disconnect(dev);
1056 			udelay(1000);
1057 			if (dev->mode == IMM_EPP_32) {
1058 				dev->mode = old_mode;
1059 				goto second_pass;
1060 			}
1061 			printk("imm: Unable to establish communication\n");
1062 			return -EIO;
1063 		}
1064 		w_ctr(ppb, 0x0c);
1065 
1066 		k = 1000000;	/* 1 Second */
1067 		do {
1068 			l = r_str(ppb);
1069 			k--;
1070 			udelay(1);
1071 		} while (!(l & 0x80) && (k));
1072 
1073 		l &= 0xb8;
1074 
1075 		if (l != 0xb8) {
1076 			imm_disconnect(dev);
1077 			imm_connect(dev, CONNECT_EPP_MAYBE);
1078 			imm_reset_pulse(dev->base);
1079 			udelay(1000);
1080 			imm_disconnect(dev);
1081 			udelay(1000);
1082 			if (dev->mode == IMM_EPP_32) {
1083 				dev->mode = old_mode;
1084 				goto second_pass;
1085 			}
1086 			printk
1087 			    ("imm: Unable to establish communication\n");
1088 			return -EIO;
1089 		}
1090 		imm_disconnect(dev);
1091 		printk
1092 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1093 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1094 		imm_connect(dev, CONNECT_EPP_MAYBE);
1095 		imm_reset_pulse(dev->base);
1096 		udelay(1000);
1097 		imm_disconnect(dev);
1098 		udelay(1000);
1099 		return 0;
1100 	}
1101 	printk("imm: No devices found\n");
1102 	return -ENODEV;
1103 }
1104 
1105 /*
1106  * imm cannot deal with highmem, so this causes all IO pages for this host
1107  * to reside in low memory (hence mapped)
1108  */
1109 static int imm_adjust_queue(struct scsi_device *device)
1110 {
1111 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1112 	return 0;
1113 }
1114 
1115 static struct scsi_host_template imm_template = {
1116 	.module			= THIS_MODULE,
1117 	.proc_name		= "imm",
1118 	.proc_info		= imm_proc_info,
1119 	.name			= "Iomega VPI2 (imm) interface",
1120 	.queuecommand		= imm_queuecommand,
1121 	.eh_abort_handler	= imm_abort,
1122 	.eh_bus_reset_handler	= imm_reset,
1123 	.eh_host_reset_handler	= imm_reset,
1124 	.bios_param		= imm_biosparam,
1125 	.this_id		= 7,
1126 	.sg_tablesize		= SG_ALL,
1127 	.cmd_per_lun		= 1,
1128 	.use_clustering		= ENABLE_CLUSTERING,
1129 	.can_queue		= 1,
1130 	.slave_alloc		= imm_adjust_queue,
1131 };
1132 
1133 /***************************************************************************
1134  *                   Parallel port probing routines                        *
1135  ***************************************************************************/
1136 
1137 static LIST_HEAD(imm_hosts);
1138 
1139 static int __imm_attach(struct parport *pb)
1140 {
1141 	struct Scsi_Host *host;
1142 	imm_struct *dev;
1143 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1144 	DEFINE_WAIT(wait);
1145 	int ports;
1146 	int modes, ppb;
1147 	int err = -ENOMEM;
1148 
1149 	init_waitqueue_head(&waiting);
1150 
1151 	dev = kzalloc(sizeof(imm_struct), GFP_KERNEL);
1152 	if (!dev)
1153 		return -ENOMEM;
1154 
1155 
1156 	dev->base = -1;
1157 	dev->mode = IMM_AUTODETECT;
1158 	INIT_LIST_HEAD(&dev->list);
1159 
1160 	dev->dev = parport_register_device(pb, "imm", NULL, imm_wakeup,
1161 						NULL, 0, dev);
1162 
1163 	if (!dev->dev)
1164 		goto out;
1165 
1166 
1167 	/* Claim the bus so it remembers what we do to the control
1168 	 * registers. [ CTR and ECP ]
1169 	 */
1170 	err = -EBUSY;
1171 	dev->waiting = &waiting;
1172 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1173 	if (imm_pb_claim(dev))
1174 		schedule_timeout(3 * HZ);
1175 	if (dev->wanted) {
1176 		printk(KERN_ERR "imm%d: failed to claim parport because "
1177 			"a pardevice is owning the port for too long "
1178 			"time!\n", pb->number);
1179 		imm_pb_dismiss(dev);
1180 		dev->waiting = NULL;
1181 		finish_wait(&waiting, &wait);
1182 		goto out1;
1183 	}
1184 	dev->waiting = NULL;
1185 	finish_wait(&waiting, &wait);
1186 	ppb = dev->base = dev->dev->port->base;
1187 	dev->base_hi = dev->dev->port->base_hi;
1188 	w_ctr(ppb, 0x0c);
1189 	modes = dev->dev->port->modes;
1190 
1191 	/* Mode detection works up the chain of speed
1192 	 * This avoids a nasty if-then-else-if-... tree
1193 	 */
1194 	dev->mode = IMM_NIBBLE;
1195 
1196 	if (modes & PARPORT_MODE_TRISTATE)
1197 		dev->mode = IMM_PS2;
1198 
1199 	/* Done configuration */
1200 
1201 	err = imm_init(dev);
1202 
1203 	imm_pb_release(dev);
1204 
1205 	if (err)
1206 		goto out1;
1207 
1208 	/* now the glue ... */
1209 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1210 		ports = 3;
1211 	else
1212 		ports = 8;
1213 
1214 	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1215 
1216 	err = -ENOMEM;
1217 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1218 	if (!host)
1219 		goto out1;
1220 	host->io_port = pb->base;
1221 	host->n_io_port = ports;
1222 	host->dma_channel = -1;
1223 	host->unique_id = pb->number;
1224 	*(imm_struct **)&host->hostdata = dev;
1225 	dev->host = host;
1226 	list_add_tail(&dev->list, &imm_hosts);
1227 	err = scsi_add_host(host, NULL);
1228 	if (err)
1229 		goto out2;
1230 	scsi_scan_host(host);
1231 	return 0;
1232 
1233 out2:
1234 	list_del_init(&dev->list);
1235 	scsi_host_put(host);
1236 out1:
1237 	parport_unregister_device(dev->dev);
1238 out:
1239 	kfree(dev);
1240 	return err;
1241 }
1242 
1243 static void imm_attach(struct parport *pb)
1244 {
1245 	__imm_attach(pb);
1246 }
1247 
1248 static void imm_detach(struct parport *pb)
1249 {
1250 	imm_struct *dev;
1251 	list_for_each_entry(dev, &imm_hosts, list) {
1252 		if (dev->dev->port == pb) {
1253 			list_del_init(&dev->list);
1254 			scsi_remove_host(dev->host);
1255 			scsi_host_put(dev->host);
1256 			parport_unregister_device(dev->dev);
1257 			kfree(dev);
1258 			break;
1259 		}
1260 	}
1261 }
1262 
1263 static struct parport_driver imm_driver = {
1264 	.name	= "imm",
1265 	.attach	= imm_attach,
1266 	.detach	= imm_detach,
1267 };
1268 
1269 static int __init imm_driver_init(void)
1270 {
1271 	printk("imm: Version %s\n", IMM_VERSION);
1272 	return parport_register_driver(&imm_driver);
1273 }
1274 
1275 static void __exit imm_driver_exit(void)
1276 {
1277 	parport_unregister_driver(&imm_driver);
1278 }
1279 
1280 module_init(imm_driver_init);
1281 module_exit(imm_driver_exit);
1282 
1283 MODULE_LICENSE("GPL");
1284