xref: /openbmc/linux/drivers/scsi/imm.c (revision 64c70b1c)
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, __FUNCTION__, __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 =
709 				    page_address(cmd->SCp.buffer->page) +
710 				    cmd->SCp.buffer->offset;
711 
712 				/*
713 				 * Make sure that we transfer even number of bytes
714 				 * otherwise it makes imm_byte_out() messy.
715 				 */
716 				if (cmd->SCp.this_residual & 0x01)
717 					cmd->SCp.this_residual++;
718 			}
719 		}
720 		/* Now check to see if the drive is ready to comunicate */
721 		w_ctr(ppb, 0x0c);
722 		r = (r_str(ppb) & 0xb8);
723 
724 		/* If not, drop back down to the scheduler and wait a timer tick */
725 		if (!(r & 0x80))
726 			return 0;
727 	}
728 	return 1;		/* FINISH_RETURN */
729 }
730 
731 /*
732  * Since the IMM itself doesn't generate interrupts, we use
733  * the scheduler's task queue to generate a stream of call-backs and
734  * complete the request when the drive is ready.
735  */
736 static void imm_interrupt(struct work_struct *work)
737 {
738 	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
739 	struct scsi_cmnd *cmd = dev->cur_cmd;
740 	struct Scsi_Host *host = cmd->device->host;
741 	unsigned long flags;
742 
743 	if (!cmd) {
744 		printk("IMM: bug in imm_interrupt\n");
745 		return;
746 	}
747 	if (imm_engine(dev, cmd)) {
748 		schedule_delayed_work(&dev->imm_tq, 1);
749 		return;
750 	}
751 	/* Command must of completed hence it is safe to let go... */
752 #if IMM_DEBUG > 0
753 	switch ((cmd->result >> 16) & 0xff) {
754 	case DID_OK:
755 		break;
756 	case DID_NO_CONNECT:
757 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
758 		break;
759 	case DID_BUS_BUSY:
760 		printk("imm: BUS BUSY - EPP timeout detected\n");
761 		break;
762 	case DID_TIME_OUT:
763 		printk("imm: unknown timeout\n");
764 		break;
765 	case DID_ABORT:
766 		printk("imm: told to abort\n");
767 		break;
768 	case DID_PARITY:
769 		printk("imm: parity error (???)\n");
770 		break;
771 	case DID_ERROR:
772 		printk("imm: internal driver error\n");
773 		break;
774 	case DID_RESET:
775 		printk("imm: told to reset device\n");
776 		break;
777 	case DID_BAD_INTR:
778 		printk("imm: bad interrupt (???)\n");
779 		break;
780 	default:
781 		printk("imm: bad return code (%02x)\n",
782 		       (cmd->result >> 16) & 0xff);
783 	}
784 #endif
785 
786 	if (cmd->SCp.phase > 1)
787 		imm_disconnect(dev);
788 
789 	imm_pb_dismiss(dev);
790 
791 	spin_lock_irqsave(host->host_lock, flags);
792 	dev->cur_cmd = NULL;
793 	cmd->scsi_done(cmd);
794 	spin_unlock_irqrestore(host->host_lock, flags);
795 	return;
796 }
797 
798 static int imm_engine(imm_struct *dev, struct scsi_cmnd *cmd)
799 {
800 	unsigned short ppb = dev->base;
801 	unsigned char l = 0, h = 0;
802 	int retv, x;
803 
804 	/* First check for any errors that may have occurred
805 	 * Here we check for internal errors
806 	 */
807 	if (dev->failed)
808 		return 0;
809 
810 	switch (cmd->SCp.phase) {
811 	case 0:		/* Phase 0 - Waiting for parport */
812 		if (time_after(jiffies, dev->jstart + HZ)) {
813 			/*
814 			 * We waited more than a second
815 			 * for parport to call us
816 			 */
817 			imm_fail(dev, DID_BUS_BUSY);
818 			return 0;
819 		}
820 		return 1;	/* wait until imm_wakeup claims parport */
821 		/* Phase 1 - Connected */
822 	case 1:
823 		imm_connect(dev, CONNECT_EPP_MAYBE);
824 		cmd->SCp.phase++;
825 
826 		/* Phase 2 - We are now talking to the scsi bus */
827 	case 2:
828 		if (!imm_select(dev, scmd_id(cmd))) {
829 			imm_fail(dev, DID_NO_CONNECT);
830 			return 0;
831 		}
832 		cmd->SCp.phase++;
833 
834 		/* Phase 3 - Ready to accept a command */
835 	case 3:
836 		w_ctr(ppb, 0x0c);
837 		if (!(r_str(ppb) & 0x80))
838 			return 1;
839 
840 		if (!imm_send_command(cmd))
841 			return 0;
842 		cmd->SCp.phase++;
843 
844 		/* Phase 4 - Setup scatter/gather buffers */
845 	case 4:
846 		if (cmd->use_sg) {
847 			/* if many buffers are available, start filling the first */
848 			cmd->SCp.buffer =
849 			    (struct scatterlist *) cmd->request_buffer;
850 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
851 			cmd->SCp.ptr =
852 			    page_address(cmd->SCp.buffer->page) +
853 			    cmd->SCp.buffer->offset;
854 		} else {
855 			/* else fill the only available buffer */
856 			cmd->SCp.buffer = NULL;
857 			cmd->SCp.this_residual = cmd->request_bufflen;
858 			cmd->SCp.ptr = cmd->request_buffer;
859 		}
860 		cmd->SCp.buffers_residual = cmd->use_sg - 1;
861 		cmd->SCp.phase++;
862 		if (cmd->SCp.this_residual & 0x01)
863 			cmd->SCp.this_residual++;
864 		/* Phase 5 - Pre-Data transfer stage */
865 	case 5:
866 		/* Spin lock for BUSY */
867 		w_ctr(ppb, 0x0c);
868 		if (!(r_str(ppb) & 0x80))
869 			return 1;
870 
871 		/* Require negotiation for read requests */
872 		x = (r_str(ppb) & 0xb8);
873 		dev->rd = (x & 0x10) ? 1 : 0;
874 		dev->dp = (x & 0x20) ? 0 : 1;
875 
876 		if ((dev->dp) && (dev->rd))
877 			if (imm_negotiate(dev))
878 				return 0;
879 		cmd->SCp.phase++;
880 
881 		/* Phase 6 - Data transfer stage */
882 	case 6:
883 		/* Spin lock for BUSY */
884 		w_ctr(ppb, 0x0c);
885 		if (!(r_str(ppb) & 0x80))
886 			return 1;
887 
888 		if (dev->dp) {
889 			retv = imm_completion(cmd);
890 			if (retv == -1)
891 				return 0;
892 			if (retv == 0)
893 				return 1;
894 		}
895 		cmd->SCp.phase++;
896 
897 		/* Phase 7 - Post data transfer stage */
898 	case 7:
899 		if ((dev->dp) && (dev->rd)) {
900 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
901 				w_ctr(ppb, 0x4);
902 				w_ctr(ppb, 0xc);
903 				w_ctr(ppb, 0xe);
904 				w_ctr(ppb, 0x4);
905 			}
906 		}
907 		cmd->SCp.phase++;
908 
909 		/* Phase 8 - Read status/message */
910 	case 8:
911 		/* Check for data overrun */
912 		if (imm_wait(dev) != (unsigned char) 0xb8) {
913 			imm_fail(dev, DID_ERROR);
914 			return 0;
915 		}
916 		if (imm_negotiate(dev))
917 			return 0;
918 		if (imm_in(dev, &l, 1)) {	/* read status byte */
919 			/* Check for optional message byte */
920 			if (imm_wait(dev) == (unsigned char) 0xb8)
921 				imm_in(dev, &h, 1);
922 			cmd->result = (DID_OK << 16) + (l & STATUS_MASK);
923 		}
924 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
925 			w_ctr(ppb, 0x4);
926 			w_ctr(ppb, 0xc);
927 			w_ctr(ppb, 0xe);
928 			w_ctr(ppb, 0x4);
929 		}
930 		return 0;	/* Finished */
931 		break;
932 
933 	default:
934 		printk("imm: Invalid scsi phase\n");
935 	}
936 	return 0;
937 }
938 
939 static int imm_queuecommand(struct scsi_cmnd *cmd,
940 		void (*done)(struct scsi_cmnd *))
941 {
942 	imm_struct *dev = imm_dev(cmd->device->host);
943 
944 	if (dev->cur_cmd) {
945 		printk("IMM: bug in imm_queuecommand\n");
946 		return 0;
947 	}
948 	dev->failed = 0;
949 	dev->jstart = jiffies;
950 	dev->cur_cmd = cmd;
951 	cmd->scsi_done = done;
952 	cmd->result = DID_ERROR << 16;	/* default return code */
953 	cmd->SCp.phase = 0;	/* bus free */
954 
955 	schedule_delayed_work(&dev->imm_tq, 0);
956 
957 	imm_pb_claim(dev);
958 
959 	return 0;
960 }
961 
962 /*
963  * Apparently the disk->capacity attribute is off by 1 sector
964  * for all disk drives.  We add the one here, but it should really
965  * be done in sd.c.  Even if it gets fixed there, this will still
966  * work.
967  */
968 static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
969 			 sector_t capacity, int ip[])
970 {
971 	ip[0] = 0x40;
972 	ip[1] = 0x20;
973 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
974 	if (ip[2] > 1024) {
975 		ip[0] = 0xff;
976 		ip[1] = 0x3f;
977 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
978 	}
979 	return 0;
980 }
981 
982 static int imm_abort(struct scsi_cmnd *cmd)
983 {
984 	imm_struct *dev = imm_dev(cmd->device->host);
985 	/*
986 	 * There is no method for aborting commands since Iomega
987 	 * have tied the SCSI_MESSAGE line high in the interface
988 	 */
989 
990 	switch (cmd->SCp.phase) {
991 	case 0:		/* Do not have access to parport */
992 	case 1:		/* Have not connected to interface */
993 		dev->cur_cmd = NULL;	/* Forget the problem */
994 		return SUCCESS;
995 		break;
996 	default:		/* SCSI command sent, can not abort */
997 		return FAILED;
998 		break;
999 	}
1000 }
1001 
1002 static void imm_reset_pulse(unsigned int base)
1003 {
1004 	w_ctr(base, 0x04);
1005 	w_dtr(base, 0x40);
1006 	udelay(1);
1007 	w_ctr(base, 0x0c);
1008 	w_ctr(base, 0x0d);
1009 	udelay(50);
1010 	w_ctr(base, 0x0c);
1011 	w_ctr(base, 0x04);
1012 }
1013 
1014 static int imm_reset(struct scsi_cmnd *cmd)
1015 {
1016 	imm_struct *dev = imm_dev(cmd->device->host);
1017 
1018 	if (cmd->SCp.phase)
1019 		imm_disconnect(dev);
1020 	dev->cur_cmd = NULL;	/* Forget the problem */
1021 
1022 	imm_connect(dev, CONNECT_NORMAL);
1023 	imm_reset_pulse(dev->base);
1024 	mdelay(1);		/* device settle delay */
1025 	imm_disconnect(dev);
1026 	mdelay(1);		/* device settle delay */
1027 	return SUCCESS;
1028 }
1029 
1030 static int device_check(imm_struct *dev)
1031 {
1032 	/* This routine looks for a device and then attempts to use EPP
1033 	   to send a command. If all goes as planned then EPP is available. */
1034 
1035 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1036 	int loop, old_mode, status, k, ppb = dev->base;
1037 	unsigned char l;
1038 
1039 	old_mode = dev->mode;
1040 	for (loop = 0; loop < 8; loop++) {
1041 		/* Attempt to use EPP for Test Unit Ready */
1042 		if ((ppb & 0x0007) == 0x0000)
1043 			dev->mode = IMM_EPP_32;
1044 
1045 	      second_pass:
1046 		imm_connect(dev, CONNECT_EPP_MAYBE);
1047 		/* Select SCSI device */
1048 		if (!imm_select(dev, loop)) {
1049 			imm_disconnect(dev);
1050 			continue;
1051 		}
1052 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1053 		       loop, IMM_MODE_STRING[dev->mode]);
1054 
1055 		/* Send SCSI command */
1056 		status = 1;
1057 		w_ctr(ppb, 0x0c);
1058 		for (l = 0; (l < 3) && (status); l++)
1059 			status = imm_out(dev, &cmd[l << 1], 2);
1060 
1061 		if (!status) {
1062 			imm_disconnect(dev);
1063 			imm_connect(dev, CONNECT_EPP_MAYBE);
1064 			imm_reset_pulse(dev->base);
1065 			udelay(1000);
1066 			imm_disconnect(dev);
1067 			udelay(1000);
1068 			if (dev->mode == IMM_EPP_32) {
1069 				dev->mode = old_mode;
1070 				goto second_pass;
1071 			}
1072 			printk("imm: Unable to establish communication\n");
1073 			return -EIO;
1074 		}
1075 		w_ctr(ppb, 0x0c);
1076 
1077 		k = 1000000;	/* 1 Second */
1078 		do {
1079 			l = r_str(ppb);
1080 			k--;
1081 			udelay(1);
1082 		} while (!(l & 0x80) && (k));
1083 
1084 		l &= 0xb8;
1085 
1086 		if (l != 0xb8) {
1087 			imm_disconnect(dev);
1088 			imm_connect(dev, CONNECT_EPP_MAYBE);
1089 			imm_reset_pulse(dev->base);
1090 			udelay(1000);
1091 			imm_disconnect(dev);
1092 			udelay(1000);
1093 			if (dev->mode == IMM_EPP_32) {
1094 				dev->mode = old_mode;
1095 				goto second_pass;
1096 			}
1097 			printk
1098 			    ("imm: Unable to establish communication\n");
1099 			return -EIO;
1100 		}
1101 		imm_disconnect(dev);
1102 		printk
1103 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1104 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1105 		imm_connect(dev, CONNECT_EPP_MAYBE);
1106 		imm_reset_pulse(dev->base);
1107 		udelay(1000);
1108 		imm_disconnect(dev);
1109 		udelay(1000);
1110 		return 0;
1111 	}
1112 	printk("imm: No devices found\n");
1113 	return -ENODEV;
1114 }
1115 
1116 /*
1117  * imm cannot deal with highmem, so this causes all IO pages for this host
1118  * to reside in low memory (hence mapped)
1119  */
1120 static int imm_adjust_queue(struct scsi_device *device)
1121 {
1122 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1123 	return 0;
1124 }
1125 
1126 static struct scsi_host_template imm_template = {
1127 	.module			= THIS_MODULE,
1128 	.proc_name		= "imm",
1129 	.proc_info		= imm_proc_info,
1130 	.name			= "Iomega VPI2 (imm) interface",
1131 	.queuecommand		= imm_queuecommand,
1132 	.eh_abort_handler	= imm_abort,
1133 	.eh_bus_reset_handler	= imm_reset,
1134 	.eh_host_reset_handler	= imm_reset,
1135 	.bios_param		= imm_biosparam,
1136 	.this_id		= 7,
1137 	.sg_tablesize		= SG_ALL,
1138 	.cmd_per_lun		= 1,
1139 	.use_clustering		= ENABLE_CLUSTERING,
1140 	.can_queue		= 1,
1141 	.slave_alloc		= imm_adjust_queue,
1142 };
1143 
1144 /***************************************************************************
1145  *                   Parallel port probing routines                        *
1146  ***************************************************************************/
1147 
1148 static LIST_HEAD(imm_hosts);
1149 
1150 static int __imm_attach(struct parport *pb)
1151 {
1152 	struct Scsi_Host *host;
1153 	imm_struct *dev;
1154 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1155 	DEFINE_WAIT(wait);
1156 	int ports;
1157 	int modes, ppb;
1158 	int err = -ENOMEM;
1159 
1160 	init_waitqueue_head(&waiting);
1161 
1162 	dev = kmalloc(sizeof(imm_struct), GFP_KERNEL);
1163 	if (!dev)
1164 		return -ENOMEM;
1165 
1166 	memset(dev, 0, sizeof(imm_struct));
1167 
1168 	dev->base = -1;
1169 	dev->mode = IMM_AUTODETECT;
1170 	INIT_LIST_HEAD(&dev->list);
1171 
1172 	dev->dev = parport_register_device(pb, "imm", NULL, imm_wakeup,
1173 						NULL, 0, dev);
1174 
1175 	if (!dev->dev)
1176 		goto out;
1177 
1178 
1179 	/* Claim the bus so it remembers what we do to the control
1180 	 * registers. [ CTR and ECP ]
1181 	 */
1182 	err = -EBUSY;
1183 	dev->waiting = &waiting;
1184 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1185 	if (imm_pb_claim(dev))
1186 		schedule_timeout(3 * HZ);
1187 	if (dev->wanted) {
1188 		printk(KERN_ERR "imm%d: failed to claim parport because "
1189 			"a pardevice is owning the port for too long "
1190 			"time!\n", pb->number);
1191 		imm_pb_dismiss(dev);
1192 		dev->waiting = NULL;
1193 		finish_wait(&waiting, &wait);
1194 		goto out1;
1195 	}
1196 	dev->waiting = NULL;
1197 	finish_wait(&waiting, &wait);
1198 	ppb = dev->base = dev->dev->port->base;
1199 	dev->base_hi = dev->dev->port->base_hi;
1200 	w_ctr(ppb, 0x0c);
1201 	modes = dev->dev->port->modes;
1202 
1203 	/* Mode detection works up the chain of speed
1204 	 * This avoids a nasty if-then-else-if-... tree
1205 	 */
1206 	dev->mode = IMM_NIBBLE;
1207 
1208 	if (modes & PARPORT_MODE_TRISTATE)
1209 		dev->mode = IMM_PS2;
1210 
1211 	/* Done configuration */
1212 
1213 	err = imm_init(dev);
1214 
1215 	imm_pb_release(dev);
1216 
1217 	if (err)
1218 		goto out1;
1219 
1220 	/* now the glue ... */
1221 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1222 		ports = 3;
1223 	else
1224 		ports = 8;
1225 
1226 	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1227 
1228 	err = -ENOMEM;
1229 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1230 	if (!host)
1231 		goto out1;
1232 	host->io_port = pb->base;
1233 	host->n_io_port = ports;
1234 	host->dma_channel = -1;
1235 	host->unique_id = pb->number;
1236 	*(imm_struct **)&host->hostdata = dev;
1237 	dev->host = host;
1238 	list_add_tail(&dev->list, &imm_hosts);
1239 	err = scsi_add_host(host, NULL);
1240 	if (err)
1241 		goto out2;
1242 	scsi_scan_host(host);
1243 	return 0;
1244 
1245 out2:
1246 	list_del_init(&dev->list);
1247 	scsi_host_put(host);
1248 out1:
1249 	parport_unregister_device(dev->dev);
1250 out:
1251 	kfree(dev);
1252 	return err;
1253 }
1254 
1255 static void imm_attach(struct parport *pb)
1256 {
1257 	__imm_attach(pb);
1258 }
1259 
1260 static void imm_detach(struct parport *pb)
1261 {
1262 	imm_struct *dev;
1263 	list_for_each_entry(dev, &imm_hosts, list) {
1264 		if (dev->dev->port == pb) {
1265 			list_del_init(&dev->list);
1266 			scsi_remove_host(dev->host);
1267 			scsi_host_put(dev->host);
1268 			parport_unregister_device(dev->dev);
1269 			kfree(dev);
1270 			break;
1271 		}
1272 	}
1273 }
1274 
1275 static struct parport_driver imm_driver = {
1276 	.name	= "imm",
1277 	.attach	= imm_attach,
1278 	.detach	= imm_detach,
1279 };
1280 
1281 static int __init imm_driver_init(void)
1282 {
1283 	printk("imm: Version %s\n", IMM_VERSION);
1284 	return parport_register_driver(&imm_driver);
1285 }
1286 
1287 static void __exit imm_driver_exit(void)
1288 {
1289 	parport_unregister_driver(&imm_driver);
1290 }
1291 
1292 module_init(imm_driver_init);
1293 module_exit(imm_driver_exit);
1294 
1295 MODULE_LICENSE("GPL");
1296