xref: /openbmc/linux/drivers/scsi/imm.c (revision 87c2ce3b)
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  * Current Maintainer: David Campbell (Perth, Western Australia)
7  *                     campbell@torque.net
8  *
9  * My unoffical company acronym list is 21 pages long:
10  *      FLA:    Four letter acronym with built in facility for
11  *              future expansion to five letters.
12  */
13 
14 #include <linux/config.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/blkdev.h>
19 #include <linux/parport.h>
20 #include <linux/workqueue.h>
21 #include <linux/delay.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 /* The following #define is to avoid a clash with hosts.c */
30 #define IMM_PROBE_SPP   0x0001
31 #define IMM_PROBE_PS2   0x0002
32 #define IMM_PROBE_ECR   0x0010
33 #define IMM_PROBE_EPP17 0x0100
34 #define IMM_PROBE_EPP19 0x0200
35 
36 
37 typedef struct {
38 	struct pardevice *dev;	/* Parport device entry         */
39 	int base;		/* Actual port address          */
40 	int base_hi;		/* Hi Base address for ECP-ISA chipset */
41 	int mode;		/* Transfer mode                */
42 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
43 	struct work_struct imm_tq;	/* Polling interrupt stuff       */
44 	unsigned long jstart;	/* Jiffies at start             */
45 	unsigned failed:1;	/* Failure flag                 */
46 	unsigned dp:1;		/* Data phase present           */
47 	unsigned rd:1;		/* Read data in data phase      */
48 	unsigned wanted:1;	/* Parport sharing busy flag    */
49 	wait_queue_head_t *waiting;
50 	struct Scsi_Host *host;
51 	struct list_head list;
52 } imm_struct;
53 
54 static void imm_reset_pulse(unsigned int base);
55 static int device_check(imm_struct *dev);
56 
57 #include "imm.h"
58 
59 static inline imm_struct *imm_dev(struct Scsi_Host *host)
60 {
61 	return *(imm_struct **)&host->hostdata;
62 }
63 
64 static DEFINE_SPINLOCK(arbitration_lock);
65 
66 static void got_it(imm_struct *dev)
67 {
68 	dev->base = dev->dev->port->base;
69 	if (dev->cur_cmd)
70 		dev->cur_cmd->SCp.phase = 1;
71 	else
72 		wake_up(dev->waiting);
73 }
74 
75 static void imm_wakeup(void *ref)
76 {
77 	imm_struct *dev = (imm_struct *) ref;
78 	unsigned long flags;
79 
80 	spin_lock_irqsave(&arbitration_lock, flags);
81 	if (dev->wanted) {
82 		parport_claim(dev->dev);
83 		got_it(dev);
84 		dev->wanted = 0;
85 	}
86 	spin_unlock_irqrestore(&arbitration_lock, flags);
87 }
88 
89 static int imm_pb_claim(imm_struct *dev)
90 {
91 	unsigned long flags;
92 	int res = 1;
93 	spin_lock_irqsave(&arbitration_lock, flags);
94 	if (parport_claim(dev->dev) == 0) {
95 		got_it(dev);
96 		res = 0;
97 	}
98 	dev->wanted = res;
99 	spin_unlock_irqrestore(&arbitration_lock, flags);
100 	return res;
101 }
102 
103 static void imm_pb_dismiss(imm_struct *dev)
104 {
105 	unsigned long flags;
106 	int wanted;
107 	spin_lock_irqsave(&arbitration_lock, flags);
108 	wanted = dev->wanted;
109 	dev->wanted = 0;
110 	spin_unlock_irqrestore(&arbitration_lock, flags);
111 	if (!wanted)
112 		parport_release(dev->dev);
113 }
114 
115 static inline void imm_pb_release(imm_struct *dev)
116 {
117 	parport_release(dev->dev);
118 }
119 
120 /* This is to give the imm driver a way to modify the timings (and other
121  * parameters) by writing to the /proc/scsi/imm/0 file.
122  * Very simple method really... (Too simple, no error checking :( )
123  * Reason: Kernel hackers HATE having to unload and reload modules for
124  * testing...
125  * Also gives a method to use a script to obtain optimum timings (TODO)
126  */
127 static inline int imm_proc_write(imm_struct *dev, char *buffer, int length)
128 {
129 	unsigned long x;
130 
131 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
132 		x = simple_strtoul(buffer + 5, NULL, 0);
133 		dev->mode = x;
134 		return length;
135 	}
136 	printk("imm /proc: invalid variable\n");
137 	return (-EINVAL);
138 }
139 
140 static int imm_proc_info(struct Scsi_Host *host, char *buffer, char **start,
141 			off_t offset, int length, int inout)
142 {
143 	imm_struct *dev = imm_dev(host);
144 	int len = 0;
145 
146 	if (inout)
147 		return imm_proc_write(dev, buffer, length);
148 
149 	len += sprintf(buffer + len, "Version : %s\n", IMM_VERSION);
150 	len +=
151 	    sprintf(buffer + len, "Parport : %s\n",
152 		    dev->dev->port->name);
153 	len +=
154 	    sprintf(buffer + len, "Mode    : %s\n",
155 		    IMM_MODE_STRING[dev->mode]);
156 
157 	/* Request for beyond end of buffer */
158 	if (offset > len)
159 		return 0;
160 
161 	*start = buffer + offset;
162 	len -= offset;
163 	if (len > length)
164 		len = length;
165 	return len;
166 }
167 
168 #if IMM_DEBUG > 0
169 #define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
170 	   y, __FUNCTION__, __LINE__); imm_fail_func(x,y);
171 static inline void
172 imm_fail_func(imm_struct *dev, int error_code)
173 #else
174 static inline void
175 imm_fail(imm_struct *dev, int error_code)
176 #endif
177 {
178 	/* If we fail a device then we trash status / message bytes */
179 	if (dev->cur_cmd) {
180 		dev->cur_cmd->result = error_code << 16;
181 		dev->failed = 1;
182 	}
183 }
184 
185 /*
186  * Wait for the high bit to be set.
187  *
188  * In principle, this could be tied to an interrupt, but the adapter
189  * doesn't appear to be designed to support interrupts.  We spin on
190  * the 0x80 ready bit.
191  */
192 static unsigned char imm_wait(imm_struct *dev)
193 {
194 	int k;
195 	unsigned short ppb = dev->base;
196 	unsigned char r;
197 
198 	w_ctr(ppb, 0x0c);
199 
200 	k = IMM_SPIN_TMO;
201 	do {
202 		r = r_str(ppb);
203 		k--;
204 		udelay(1);
205 	}
206 	while (!(r & 0x80) && (k));
207 
208 	/*
209 	 * STR register (LPT base+1) to SCSI mapping:
210 	 *
211 	 * STR      imm     imm
212 	 * ===================================
213 	 * 0x80     S_REQ   S_REQ
214 	 * 0x40     !S_BSY  (????)
215 	 * 0x20     !S_CD   !S_CD
216 	 * 0x10     !S_IO   !S_IO
217 	 * 0x08     (????)  !S_BSY
218 	 *
219 	 * imm      imm     meaning
220 	 * ==================================
221 	 * 0xf0     0xb8    Bit mask
222 	 * 0xc0     0x88    ZIP wants more data
223 	 * 0xd0     0x98    ZIP wants to send more data
224 	 * 0xe0     0xa8    ZIP is expecting SCSI command data
225 	 * 0xf0     0xb8    end of transfer, ZIP is sending status
226 	 */
227 	w_ctr(ppb, 0x04);
228 	if (k)
229 		return (r & 0xb8);
230 
231 	/* Counter expired - Time out occurred */
232 	imm_fail(dev, DID_TIME_OUT);
233 	printk("imm timeout in imm_wait\n");
234 	return 0;		/* command timed out */
235 }
236 
237 static int imm_negotiate(imm_struct * tmp)
238 {
239 	/*
240 	 * The following is supposedly the IEEE 1284-1994 negotiate
241 	 * sequence. I have yet to obtain a copy of the above standard
242 	 * so this is a bit of a guess...
243 	 *
244 	 * A fair chunk of this is based on the Linux parport implementation
245 	 * of IEEE 1284.
246 	 *
247 	 * Return 0 if data available
248 	 *        1 if no data available
249 	 */
250 
251 	unsigned short base = tmp->base;
252 	unsigned char a, mode;
253 
254 	switch (tmp->mode) {
255 	case IMM_NIBBLE:
256 		mode = 0x00;
257 		break;
258 	case IMM_PS2:
259 		mode = 0x01;
260 		break;
261 	default:
262 		return 0;
263 	}
264 
265 	w_ctr(base, 0x04);
266 	udelay(5);
267 	w_dtr(base, mode);
268 	udelay(100);
269 	w_ctr(base, 0x06);
270 	udelay(5);
271 	a = (r_str(base) & 0x20) ? 0 : 1;
272 	udelay(5);
273 	w_ctr(base, 0x07);
274 	udelay(5);
275 	w_ctr(base, 0x06);
276 
277 	if (a) {
278 		printk
279 		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
280 		imm_fail(tmp, DID_ERROR);
281 	}
282 	return a;
283 }
284 
285 /*
286  * Clear EPP timeout bit.
287  */
288 static inline void epp_reset(unsigned short ppb)
289 {
290 	int i;
291 
292 	i = r_str(ppb);
293 	w_str(ppb, i);
294 	w_str(ppb, i & 0xfe);
295 }
296 
297 /*
298  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
299  */
300 static inline void ecp_sync(imm_struct *dev)
301 {
302 	int i, ppb_hi = dev->base_hi;
303 
304 	if (ppb_hi == 0)
305 		return;
306 
307 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
308 		for (i = 0; i < 100; i++) {
309 			if (r_ecr(ppb_hi) & 0x01)
310 				return;
311 			udelay(5);
312 		}
313 		printk("imm: ECP sync failed as data still present in FIFO.\n");
314 	}
315 }
316 
317 static int imm_byte_out(unsigned short base, const char *buffer, int len)
318 {
319 	int i;
320 
321 	w_ctr(base, 0x4);	/* apparently a sane mode */
322 	for (i = len >> 1; i; i--) {
323 		w_dtr(base, *buffer++);
324 		w_ctr(base, 0x5);	/* Drop STROBE low */
325 		w_dtr(base, *buffer++);
326 		w_ctr(base, 0x0);	/* STROBE high + INIT low */
327 	}
328 	w_ctr(base, 0x4);	/* apparently a sane mode */
329 	return 1;		/* All went well - we hope! */
330 }
331 
332 static int imm_nibble_in(unsigned short base, char *buffer, int len)
333 {
334 	unsigned char l;
335 	int i;
336 
337 	/*
338 	 * The following is based on documented timing signals
339 	 */
340 	w_ctr(base, 0x4);
341 	for (i = len; i; i--) {
342 		w_ctr(base, 0x6);
343 		l = (r_str(base) & 0xf0) >> 4;
344 		w_ctr(base, 0x5);
345 		*buffer++ = (r_str(base) & 0xf0) | l;
346 		w_ctr(base, 0x4);
347 	}
348 	return 1;		/* All went well - we hope! */
349 }
350 
351 static int imm_byte_in(unsigned short base, char *buffer, int len)
352 {
353 	int i;
354 
355 	/*
356 	 * The following is based on documented timing signals
357 	 */
358 	w_ctr(base, 0x4);
359 	for (i = len; i; i--) {
360 		w_ctr(base, 0x26);
361 		*buffer++ = r_dtr(base);
362 		w_ctr(base, 0x25);
363 	}
364 	return 1;		/* All went well - we hope! */
365 }
366 
367 static int imm_out(imm_struct *dev, char *buffer, int len)
368 {
369 	unsigned short ppb = dev->base;
370 	int r = imm_wait(dev);
371 
372 	/*
373 	 * Make sure that:
374 	 * a) the SCSI bus is BUSY (device still listening)
375 	 * b) the device is listening
376 	 */
377 	if ((r & 0x18) != 0x08) {
378 		imm_fail(dev, DID_ERROR);
379 		printk("IMM: returned SCSI status %2x\n", r);
380 		return 0;
381 	}
382 	switch (dev->mode) {
383 	case IMM_EPP_32:
384 	case IMM_EPP_16:
385 	case IMM_EPP_8:
386 		epp_reset(ppb);
387 		w_ctr(ppb, 0x4);
388 #ifdef CONFIG_SCSI_IZIP_EPP16
389 		if (!(((long) buffer | len) & 0x01))
390 			outsw(ppb + 4, buffer, len >> 1);
391 #else
392 		if (!(((long) buffer | len) & 0x03))
393 			outsl(ppb + 4, buffer, len >> 2);
394 #endif
395 		else
396 			outsb(ppb + 4, buffer, len);
397 		w_ctr(ppb, 0xc);
398 		r = !(r_str(ppb) & 0x01);
399 		w_ctr(ppb, 0xc);
400 		ecp_sync(dev);
401 		break;
402 
403 	case IMM_NIBBLE:
404 	case IMM_PS2:
405 		/* 8 bit output, with a loop */
406 		r = imm_byte_out(ppb, buffer, len);
407 		break;
408 
409 	default:
410 		printk("IMM: bug in imm_out()\n");
411 		r = 0;
412 	}
413 	return r;
414 }
415 
416 static int imm_in(imm_struct *dev, char *buffer, int len)
417 {
418 	unsigned short ppb = dev->base;
419 	int r = imm_wait(dev);
420 
421 	/*
422 	 * Make sure that:
423 	 * a) the SCSI bus is BUSY (device still listening)
424 	 * b) the device is sending data
425 	 */
426 	if ((r & 0x18) != 0x18) {
427 		imm_fail(dev, DID_ERROR);
428 		return 0;
429 	}
430 	switch (dev->mode) {
431 	case IMM_NIBBLE:
432 		/* 4 bit input, with a loop */
433 		r = imm_nibble_in(ppb, buffer, len);
434 		w_ctr(ppb, 0xc);
435 		break;
436 
437 	case IMM_PS2:
438 		/* 8 bit input, with a loop */
439 		r = imm_byte_in(ppb, buffer, len);
440 		w_ctr(ppb, 0xc);
441 		break;
442 
443 	case IMM_EPP_32:
444 	case IMM_EPP_16:
445 	case IMM_EPP_8:
446 		epp_reset(ppb);
447 		w_ctr(ppb, 0x24);
448 #ifdef CONFIG_SCSI_IZIP_EPP16
449 		if (!(((long) buffer | len) & 0x01))
450 			insw(ppb + 4, buffer, len >> 1);
451 #else
452 		if (!(((long) buffer | len) & 0x03))
453 			insl(ppb + 4, buffer, len >> 2);
454 #endif
455 		else
456 			insb(ppb + 4, buffer, len);
457 		w_ctr(ppb, 0x2c);
458 		r = !(r_str(ppb) & 0x01);
459 		w_ctr(ppb, 0x2c);
460 		ecp_sync(dev);
461 		break;
462 
463 	default:
464 		printk("IMM: bug in imm_ins()\n");
465 		r = 0;
466 		break;
467 	}
468 	return r;
469 }
470 
471 static int imm_cpp(unsigned short ppb, unsigned char b)
472 {
473 	/*
474 	 * Comments on udelay values refer to the
475 	 * Command Packet Protocol (CPP) timing diagram.
476 	 */
477 
478 	unsigned char s1, s2, s3;
479 	w_ctr(ppb, 0x0c);
480 	udelay(2);		/* 1 usec - infinite */
481 	w_dtr(ppb, 0xaa);
482 	udelay(10);		/* 7 usec - infinite */
483 	w_dtr(ppb, 0x55);
484 	udelay(10);		/* 7 usec - infinite */
485 	w_dtr(ppb, 0x00);
486 	udelay(10);		/* 7 usec - infinite */
487 	w_dtr(ppb, 0xff);
488 	udelay(10);		/* 7 usec - infinite */
489 	s1 = r_str(ppb) & 0xb8;
490 	w_dtr(ppb, 0x87);
491 	udelay(10);		/* 7 usec - infinite */
492 	s2 = r_str(ppb) & 0xb8;
493 	w_dtr(ppb, 0x78);
494 	udelay(10);		/* 7 usec - infinite */
495 	s3 = r_str(ppb) & 0x38;
496 	/*
497 	 * Values for b are:
498 	 * 0000 00aa    Assign address aa to current device
499 	 * 0010 00aa    Select device aa in EPP Winbond mode
500 	 * 0010 10aa    Select device aa in EPP mode
501 	 * 0011 xxxx    Deselect all devices
502 	 * 0110 00aa    Test device aa
503 	 * 1101 00aa    Select device aa in ECP mode
504 	 * 1110 00aa    Select device aa in Compatible mode
505 	 */
506 	w_dtr(ppb, b);
507 	udelay(2);		/* 1 usec - infinite */
508 	w_ctr(ppb, 0x0c);
509 	udelay(10);		/* 7 usec - infinite */
510 	w_ctr(ppb, 0x0d);
511 	udelay(2);		/* 1 usec - infinite */
512 	w_ctr(ppb, 0x0c);
513 	udelay(10);		/* 7 usec - infinite */
514 	w_dtr(ppb, 0xff);
515 	udelay(10);		/* 7 usec - infinite */
516 
517 	/*
518 	 * The following table is electrical pin values.
519 	 * (BSY is inverted at the CTR register)
520 	 *
521 	 *       BSY  ACK  POut SEL  Fault
522 	 * S1    0    X    1    1    1
523 	 * S2    1    X    0    1    1
524 	 * S3    L    X    1    1    S
525 	 *
526 	 * L => Last device in chain
527 	 * S => Selected
528 	 *
529 	 * Observered values for S1,S2,S3 are:
530 	 * Disconnect => f8/58/78
531 	 * Connect    => f8/58/70
532 	 */
533 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
534 		return 1;	/* Connected */
535 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
536 		return 0;	/* Disconnected */
537 
538 	return -1;		/* No device present */
539 }
540 
541 static inline int imm_connect(imm_struct *dev, int flag)
542 {
543 	unsigned short ppb = dev->base;
544 
545 	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
546 	imm_cpp(ppb, 0x30);	/* Disconnect all devices */
547 
548 	if ((dev->mode == IMM_EPP_8) ||
549 	    (dev->mode == IMM_EPP_16) ||
550 	    (dev->mode == IMM_EPP_32))
551 		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
552 	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
553 }
554 
555 static void imm_disconnect(imm_struct *dev)
556 {
557 	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
558 }
559 
560 static int imm_select(imm_struct *dev, int target)
561 {
562 	int k;
563 	unsigned short ppb = dev->base;
564 
565 	/*
566 	 * Firstly we want to make sure there is nothing
567 	 * holding onto the SCSI bus.
568 	 */
569 	w_ctr(ppb, 0xc);
570 
571 	k = IMM_SELECT_TMO;
572 	do {
573 		k--;
574 	} while ((r_str(ppb) & 0x08) && (k));
575 
576 	if (!k)
577 		return 0;
578 
579 	/*
580 	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
581 	 */
582 	w_ctr(ppb, 0x4);
583 	w_dtr(ppb, 0x80 | (1 << target));
584 	udelay(1);
585 
586 	/*
587 	 * Deassert SELIN first followed by STROBE
588 	 */
589 	w_ctr(ppb, 0xc);
590 	w_ctr(ppb, 0xd);
591 
592 	/*
593 	 * ACK should drop low while SELIN is deasserted.
594 	 * FAULT should drop low when the SCSI device latches the bus.
595 	 */
596 	k = IMM_SELECT_TMO;
597 	do {
598 		k--;
599 	}
600 	while (!(r_str(ppb) & 0x08) && (k));
601 
602 	/*
603 	 * Place the interface back into a sane state (status mode)
604 	 */
605 	w_ctr(ppb, 0xc);
606 	return (k) ? 1 : 0;
607 }
608 
609 static int imm_init(imm_struct *dev)
610 {
611 	if (imm_connect(dev, 0) != 1)
612 		return -EIO;
613 	imm_reset_pulse(dev->base);
614 	mdelay(1);	/* Delay to allow devices to settle */
615 	imm_disconnect(dev);
616 	mdelay(1);	/* Another delay to allow devices to settle */
617 	return device_check(dev);
618 }
619 
620 static inline int imm_send_command(struct scsi_cmnd *cmd)
621 {
622 	imm_struct *dev = imm_dev(cmd->device->host);
623 	int k;
624 
625 	/* NOTE: IMM uses byte pairs */
626 	for (k = 0; k < cmd->cmd_len; k += 2)
627 		if (!imm_out(dev, &cmd->cmnd[k], 2))
628 			return 0;
629 	return 1;
630 }
631 
632 /*
633  * The bulk flag enables some optimisations in the data transfer loops,
634  * it should be true for any command that transfers data in integral
635  * numbers of sectors.
636  *
637  * The driver appears to remain stable if we speed up the parallel port
638  * i/o in this function, but not elsewhere.
639  */
640 static int imm_completion(struct scsi_cmnd *cmd)
641 {
642 	/* Return codes:
643 	 * -1     Error
644 	 *  0     Told to schedule
645 	 *  1     Finished data transfer
646 	 */
647 	imm_struct *dev = imm_dev(cmd->device->host);
648 	unsigned short ppb = dev->base;
649 	unsigned long start_jiffies = jiffies;
650 
651 	unsigned char r, v;
652 	int fast, bulk, status;
653 
654 	v = cmd->cmnd[0];
655 	bulk = ((v == READ_6) ||
656 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
657 
658 	/*
659 	 * We only get here if the drive is ready to comunicate,
660 	 * hence no need for a full imm_wait.
661 	 */
662 	w_ctr(ppb, 0x0c);
663 	r = (r_str(ppb) & 0xb8);
664 
665 	/*
666 	 * while (device is not ready to send status byte)
667 	 *     loop;
668 	 */
669 	while (r != (unsigned char) 0xb8) {
670 		/*
671 		 * If we have been running for more than a full timer tick
672 		 * then take a rest.
673 		 */
674 		if (time_after(jiffies, start_jiffies + 1))
675 			return 0;
676 
677 		/*
678 		 * FAIL if:
679 		 * a) Drive status is screwy (!ready && !present)
680 		 * b) Drive is requesting/sending more data than expected
681 		 */
682 		if (((r & 0x88) != 0x88) || (cmd->SCp.this_residual <= 0)) {
683 			imm_fail(dev, DID_ERROR);
684 			return -1;	/* ERROR_RETURN */
685 		}
686 		/* determine if we should use burst I/O */
687 		if (dev->rd == 0) {
688 			fast = (bulk
689 				&& (cmd->SCp.this_residual >=
690 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 2;
691 			status = imm_out(dev, cmd->SCp.ptr, fast);
692 		} else {
693 			fast = (bulk
694 				&& (cmd->SCp.this_residual >=
695 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 1;
696 			status = imm_in(dev, cmd->SCp.ptr, fast);
697 		}
698 
699 		cmd->SCp.ptr += fast;
700 		cmd->SCp.this_residual -= fast;
701 
702 		if (!status) {
703 			imm_fail(dev, DID_BUS_BUSY);
704 			return -1;	/* ERROR_RETURN */
705 		}
706 		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
707 			/* if scatter/gather, advance to the next segment */
708 			if (cmd->SCp.buffers_residual--) {
709 				cmd->SCp.buffer++;
710 				cmd->SCp.this_residual =
711 				    cmd->SCp.buffer->length;
712 				cmd->SCp.ptr =
713 				    page_address(cmd->SCp.buffer->page) +
714 				    cmd->SCp.buffer->offset;
715 
716 				/*
717 				 * Make sure that we transfer even number of bytes
718 				 * otherwise it makes imm_byte_out() messy.
719 				 */
720 				if (cmd->SCp.this_residual & 0x01)
721 					cmd->SCp.this_residual++;
722 			}
723 		}
724 		/* Now check to see if the drive is ready to comunicate */
725 		w_ctr(ppb, 0x0c);
726 		r = (r_str(ppb) & 0xb8);
727 
728 		/* If not, drop back down to the scheduler and wait a timer tick */
729 		if (!(r & 0x80))
730 			return 0;
731 	}
732 	return 1;		/* FINISH_RETURN */
733 }
734 
735 /*
736  * Since the IMM itself doesn't generate interrupts, we use
737  * the scheduler's task queue to generate a stream of call-backs and
738  * complete the request when the drive is ready.
739  */
740 static void imm_interrupt(void *data)
741 {
742 	imm_struct *dev = (imm_struct *) data;
743 	struct scsi_cmnd *cmd = dev->cur_cmd;
744 	struct Scsi_Host *host = cmd->device->host;
745 	unsigned long flags;
746 
747 	if (!cmd) {
748 		printk("IMM: bug in imm_interrupt\n");
749 		return;
750 	}
751 	if (imm_engine(dev, cmd)) {
752 		INIT_WORK(&dev->imm_tq, imm_interrupt, (void *) dev);
753 		schedule_delayed_work(&dev->imm_tq, 1);
754 		return;
755 	}
756 	/* Command must of completed hence it is safe to let go... */
757 #if IMM_DEBUG > 0
758 	switch ((cmd->result >> 16) & 0xff) {
759 	case DID_OK:
760 		break;
761 	case DID_NO_CONNECT:
762 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
763 		break;
764 	case DID_BUS_BUSY:
765 		printk("imm: BUS BUSY - EPP timeout detected\n");
766 		break;
767 	case DID_TIME_OUT:
768 		printk("imm: unknown timeout\n");
769 		break;
770 	case DID_ABORT:
771 		printk("imm: told to abort\n");
772 		break;
773 	case DID_PARITY:
774 		printk("imm: parity error (???)\n");
775 		break;
776 	case DID_ERROR:
777 		printk("imm: internal driver error\n");
778 		break;
779 	case DID_RESET:
780 		printk("imm: told to reset device\n");
781 		break;
782 	case DID_BAD_INTR:
783 		printk("imm: bad interrupt (???)\n");
784 		break;
785 	default:
786 		printk("imm: bad return code (%02x)\n",
787 		       (cmd->result >> 16) & 0xff);
788 	}
789 #endif
790 
791 	if (cmd->SCp.phase > 1)
792 		imm_disconnect(dev);
793 
794 	imm_pb_dismiss(dev);
795 
796 	spin_lock_irqsave(host->host_lock, flags);
797 	dev->cur_cmd = NULL;
798 	cmd->scsi_done(cmd);
799 	spin_unlock_irqrestore(host->host_lock, flags);
800 	return;
801 }
802 
803 static int imm_engine(imm_struct *dev, struct scsi_cmnd *cmd)
804 {
805 	unsigned short ppb = dev->base;
806 	unsigned char l = 0, h = 0;
807 	int retv, x;
808 
809 	/* First check for any errors that may have occurred
810 	 * Here we check for internal errors
811 	 */
812 	if (dev->failed)
813 		return 0;
814 
815 	switch (cmd->SCp.phase) {
816 	case 0:		/* Phase 0 - Waiting for parport */
817 		if (time_after(jiffies, dev->jstart + HZ)) {
818 			/*
819 			 * We waited more than a second
820 			 * for parport to call us
821 			 */
822 			imm_fail(dev, DID_BUS_BUSY);
823 			return 0;
824 		}
825 		return 1;	/* wait until imm_wakeup claims parport */
826 		/* Phase 1 - Connected */
827 	case 1:
828 		imm_connect(dev, CONNECT_EPP_MAYBE);
829 		cmd->SCp.phase++;
830 
831 		/* Phase 2 - We are now talking to the scsi bus */
832 	case 2:
833 		if (!imm_select(dev, scmd_id(cmd))) {
834 			imm_fail(dev, DID_NO_CONNECT);
835 			return 0;
836 		}
837 		cmd->SCp.phase++;
838 
839 		/* Phase 3 - Ready to accept a command */
840 	case 3:
841 		w_ctr(ppb, 0x0c);
842 		if (!(r_str(ppb) & 0x80))
843 			return 1;
844 
845 		if (!imm_send_command(cmd))
846 			return 0;
847 		cmd->SCp.phase++;
848 
849 		/* Phase 4 - Setup scatter/gather buffers */
850 	case 4:
851 		if (cmd->use_sg) {
852 			/* if many buffers are available, start filling the first */
853 			cmd->SCp.buffer =
854 			    (struct scatterlist *) cmd->request_buffer;
855 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
856 			cmd->SCp.ptr =
857 			    page_address(cmd->SCp.buffer->page) +
858 			    cmd->SCp.buffer->offset;
859 		} else {
860 			/* else fill the only available buffer */
861 			cmd->SCp.buffer = NULL;
862 			cmd->SCp.this_residual = cmd->request_bufflen;
863 			cmd->SCp.ptr = cmd->request_buffer;
864 		}
865 		cmd->SCp.buffers_residual = cmd->use_sg - 1;
866 		cmd->SCp.phase++;
867 		if (cmd->SCp.this_residual & 0x01)
868 			cmd->SCp.this_residual++;
869 		/* Phase 5 - Pre-Data transfer stage */
870 	case 5:
871 		/* Spin lock for BUSY */
872 		w_ctr(ppb, 0x0c);
873 		if (!(r_str(ppb) & 0x80))
874 			return 1;
875 
876 		/* Require negotiation for read requests */
877 		x = (r_str(ppb) & 0xb8);
878 		dev->rd = (x & 0x10) ? 1 : 0;
879 		dev->dp = (x & 0x20) ? 0 : 1;
880 
881 		if ((dev->dp) && (dev->rd))
882 			if (imm_negotiate(dev))
883 				return 0;
884 		cmd->SCp.phase++;
885 
886 		/* Phase 6 - Data transfer stage */
887 	case 6:
888 		/* Spin lock for BUSY */
889 		w_ctr(ppb, 0x0c);
890 		if (!(r_str(ppb) & 0x80))
891 			return 1;
892 
893 		if (dev->dp) {
894 			retv = imm_completion(cmd);
895 			if (retv == -1)
896 				return 0;
897 			if (retv == 0)
898 				return 1;
899 		}
900 		cmd->SCp.phase++;
901 
902 		/* Phase 7 - Post data transfer stage */
903 	case 7:
904 		if ((dev->dp) && (dev->rd)) {
905 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
906 				w_ctr(ppb, 0x4);
907 				w_ctr(ppb, 0xc);
908 				w_ctr(ppb, 0xe);
909 				w_ctr(ppb, 0x4);
910 			}
911 		}
912 		cmd->SCp.phase++;
913 
914 		/* Phase 8 - Read status/message */
915 	case 8:
916 		/* Check for data overrun */
917 		if (imm_wait(dev) != (unsigned char) 0xb8) {
918 			imm_fail(dev, DID_ERROR);
919 			return 0;
920 		}
921 		if (imm_negotiate(dev))
922 			return 0;
923 		if (imm_in(dev, &l, 1)) {	/* read status byte */
924 			/* Check for optional message byte */
925 			if (imm_wait(dev) == (unsigned char) 0xb8)
926 				imm_in(dev, &h, 1);
927 			cmd->result = (DID_OK << 16) + (l & STATUS_MASK);
928 		}
929 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
930 			w_ctr(ppb, 0x4);
931 			w_ctr(ppb, 0xc);
932 			w_ctr(ppb, 0xe);
933 			w_ctr(ppb, 0x4);
934 		}
935 		return 0;	/* Finished */
936 		break;
937 
938 	default:
939 		printk("imm: Invalid scsi phase\n");
940 	}
941 	return 0;
942 }
943 
944 static int imm_queuecommand(struct scsi_cmnd *cmd,
945 		void (*done)(struct scsi_cmnd *))
946 {
947 	imm_struct *dev = imm_dev(cmd->device->host);
948 
949 	if (dev->cur_cmd) {
950 		printk("IMM: bug in imm_queuecommand\n");
951 		return 0;
952 	}
953 	dev->failed = 0;
954 	dev->jstart = jiffies;
955 	dev->cur_cmd = cmd;
956 	cmd->scsi_done = done;
957 	cmd->result = DID_ERROR << 16;	/* default return code */
958 	cmd->SCp.phase = 0;	/* bus free */
959 
960 	INIT_WORK(&dev->imm_tq, imm_interrupt, dev);
961 	schedule_work(&dev->imm_tq);
962 
963 	imm_pb_claim(dev);
964 
965 	return 0;
966 }
967 
968 /*
969  * Apparently the disk->capacity attribute is off by 1 sector
970  * for all disk drives.  We add the one here, but it should really
971  * be done in sd.c.  Even if it gets fixed there, this will still
972  * work.
973  */
974 static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
975 			 sector_t capacity, int ip[])
976 {
977 	ip[0] = 0x40;
978 	ip[1] = 0x20;
979 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
980 	if (ip[2] > 1024) {
981 		ip[0] = 0xff;
982 		ip[1] = 0x3f;
983 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
984 	}
985 	return 0;
986 }
987 
988 static int imm_abort(struct scsi_cmnd *cmd)
989 {
990 	imm_struct *dev = imm_dev(cmd->device->host);
991 	/*
992 	 * There is no method for aborting commands since Iomega
993 	 * have tied the SCSI_MESSAGE line high in the interface
994 	 */
995 
996 	switch (cmd->SCp.phase) {
997 	case 0:		/* Do not have access to parport */
998 	case 1:		/* Have not connected to interface */
999 		dev->cur_cmd = NULL;	/* Forget the problem */
1000 		return SUCCESS;
1001 		break;
1002 	default:		/* SCSI command sent, can not abort */
1003 		return FAILED;
1004 		break;
1005 	}
1006 }
1007 
1008 static void imm_reset_pulse(unsigned int base)
1009 {
1010 	w_ctr(base, 0x04);
1011 	w_dtr(base, 0x40);
1012 	udelay(1);
1013 	w_ctr(base, 0x0c);
1014 	w_ctr(base, 0x0d);
1015 	udelay(50);
1016 	w_ctr(base, 0x0c);
1017 	w_ctr(base, 0x04);
1018 }
1019 
1020 static int imm_reset(struct scsi_cmnd *cmd)
1021 {
1022 	imm_struct *dev = imm_dev(cmd->device->host);
1023 
1024 	if (cmd->SCp.phase)
1025 		imm_disconnect(dev);
1026 	dev->cur_cmd = NULL;	/* Forget the problem */
1027 
1028 	imm_connect(dev, CONNECT_NORMAL);
1029 	imm_reset_pulse(dev->base);
1030 	mdelay(1);		/* device settle delay */
1031 	imm_disconnect(dev);
1032 	mdelay(1);		/* device settle delay */
1033 	return SUCCESS;
1034 }
1035 
1036 static int device_check(imm_struct *dev)
1037 {
1038 	/* This routine looks for a device and then attempts to use EPP
1039 	   to send a command. If all goes as planned then EPP is available. */
1040 
1041 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1042 	int loop, old_mode, status, k, ppb = dev->base;
1043 	unsigned char l;
1044 
1045 	old_mode = dev->mode;
1046 	for (loop = 0; loop < 8; loop++) {
1047 		/* Attempt to use EPP for Test Unit Ready */
1048 		if ((ppb & 0x0007) == 0x0000)
1049 			dev->mode = IMM_EPP_32;
1050 
1051 	      second_pass:
1052 		imm_connect(dev, CONNECT_EPP_MAYBE);
1053 		/* Select SCSI device */
1054 		if (!imm_select(dev, loop)) {
1055 			imm_disconnect(dev);
1056 			continue;
1057 		}
1058 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1059 		       loop, IMM_MODE_STRING[dev->mode]);
1060 
1061 		/* Send SCSI command */
1062 		status = 1;
1063 		w_ctr(ppb, 0x0c);
1064 		for (l = 0; (l < 3) && (status); l++)
1065 			status = imm_out(dev, &cmd[l << 1], 2);
1066 
1067 		if (!status) {
1068 			imm_disconnect(dev);
1069 			imm_connect(dev, CONNECT_EPP_MAYBE);
1070 			imm_reset_pulse(dev->base);
1071 			udelay(1000);
1072 			imm_disconnect(dev);
1073 			udelay(1000);
1074 			if (dev->mode == IMM_EPP_32) {
1075 				dev->mode = old_mode;
1076 				goto second_pass;
1077 			}
1078 			printk("imm: Unable to establish communication\n");
1079 			return -EIO;
1080 		}
1081 		w_ctr(ppb, 0x0c);
1082 
1083 		k = 1000000;	/* 1 Second */
1084 		do {
1085 			l = r_str(ppb);
1086 			k--;
1087 			udelay(1);
1088 		} while (!(l & 0x80) && (k));
1089 
1090 		l &= 0xb8;
1091 
1092 		if (l != 0xb8) {
1093 			imm_disconnect(dev);
1094 			imm_connect(dev, CONNECT_EPP_MAYBE);
1095 			imm_reset_pulse(dev->base);
1096 			udelay(1000);
1097 			imm_disconnect(dev);
1098 			udelay(1000);
1099 			if (dev->mode == IMM_EPP_32) {
1100 				dev->mode = old_mode;
1101 				goto second_pass;
1102 			}
1103 			printk
1104 			    ("imm: Unable to establish communication\n");
1105 			return -EIO;
1106 		}
1107 		imm_disconnect(dev);
1108 		printk
1109 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1110 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1111 		imm_connect(dev, CONNECT_EPP_MAYBE);
1112 		imm_reset_pulse(dev->base);
1113 		udelay(1000);
1114 		imm_disconnect(dev);
1115 		udelay(1000);
1116 		return 0;
1117 	}
1118 	printk("imm: No devices found\n");
1119 	return -ENODEV;
1120 }
1121 
1122 static int imm_adjust_queue(struct scsi_device *device)
1123 {
1124 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1125 	return 0;
1126 }
1127 
1128 static struct scsi_host_template imm_template = {
1129 	.module			= THIS_MODULE,
1130 	.proc_name		= "imm",
1131 	.proc_info		= imm_proc_info,
1132 	.name			= "Iomega VPI2 (imm) interface",
1133 	.queuecommand		= imm_queuecommand,
1134 	.eh_abort_handler	= imm_abort,
1135 	.eh_bus_reset_handler	= imm_reset,
1136 	.eh_host_reset_handler	= imm_reset,
1137 	.bios_param		= imm_biosparam,
1138 	.this_id		= 7,
1139 	.sg_tablesize		= SG_ALL,
1140 	.cmd_per_lun		= 1,
1141 	.use_clustering		= ENABLE_CLUSTERING,
1142 	.can_queue		= 1,
1143 	.slave_alloc		= imm_adjust_queue,
1144 	.unchecked_isa_dma	= 1, /* imm cannot deal with highmem, so
1145 				      * this is an easy trick to ensure
1146 				      * all io pages for this host reside
1147 				      * in low memory */
1148 };
1149 
1150 /***************************************************************************
1151  *                   Parallel port probing routines                        *
1152  ***************************************************************************/
1153 
1154 static LIST_HEAD(imm_hosts);
1155 
1156 static int __imm_attach(struct parport *pb)
1157 {
1158 	struct Scsi_Host *host;
1159 	imm_struct *dev;
1160 	DECLARE_WAIT_QUEUE_HEAD(waiting);
1161 	DEFINE_WAIT(wait);
1162 	int ports;
1163 	int modes, ppb;
1164 	int err = -ENOMEM;
1165 
1166 	init_waitqueue_head(&waiting);
1167 
1168 	dev = kmalloc(sizeof(imm_struct), GFP_KERNEL);
1169 	if (!dev)
1170 		return -ENOMEM;
1171 
1172 	memset(dev, 0, sizeof(imm_struct));
1173 
1174 	dev->base = -1;
1175 	dev->mode = IMM_AUTODETECT;
1176 	INIT_LIST_HEAD(&dev->list);
1177 
1178 	dev->dev = parport_register_device(pb, "imm", NULL, imm_wakeup,
1179 						NULL, 0, dev);
1180 
1181 	if (!dev->dev)
1182 		goto out;
1183 
1184 
1185 	/* Claim the bus so it remembers what we do to the control
1186 	 * registers. [ CTR and ECP ]
1187 	 */
1188 	err = -EBUSY;
1189 	dev->waiting = &waiting;
1190 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1191 	if (imm_pb_claim(dev))
1192 		schedule_timeout(3 * HZ);
1193 	if (dev->wanted) {
1194 		printk(KERN_ERR "imm%d: failed to claim parport because "
1195 			"a pardevice is owning the port for too long "
1196 			"time!\n", pb->number);
1197 		imm_pb_dismiss(dev);
1198 		dev->waiting = NULL;
1199 		finish_wait(&waiting, &wait);
1200 		goto out1;
1201 	}
1202 	dev->waiting = NULL;
1203 	finish_wait(&waiting, &wait);
1204 	ppb = dev->base = dev->dev->port->base;
1205 	dev->base_hi = dev->dev->port->base_hi;
1206 	w_ctr(ppb, 0x0c);
1207 	modes = dev->dev->port->modes;
1208 
1209 	/* Mode detection works up the chain of speed
1210 	 * This avoids a nasty if-then-else-if-... tree
1211 	 */
1212 	dev->mode = IMM_NIBBLE;
1213 
1214 	if (modes & PARPORT_MODE_TRISTATE)
1215 		dev->mode = IMM_PS2;
1216 
1217 	/* Done configuration */
1218 
1219 	err = imm_init(dev);
1220 
1221 	imm_pb_release(dev);
1222 
1223 	if (err)
1224 		goto out1;
1225 
1226 	/* now the glue ... */
1227 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1228 		ports = 3;
1229 	else
1230 		ports = 8;
1231 
1232 	INIT_WORK(&dev->imm_tq, imm_interrupt, dev);
1233 
1234 	err = -ENOMEM;
1235 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1236 	if (!host)
1237 		goto out1;
1238 	host->io_port = pb->base;
1239 	host->n_io_port = ports;
1240 	host->dma_channel = -1;
1241 	host->unique_id = pb->number;
1242 	*(imm_struct **)&host->hostdata = dev;
1243 	dev->host = host;
1244 	list_add_tail(&dev->list, &imm_hosts);
1245 	err = scsi_add_host(host, NULL);
1246 	if (err)
1247 		goto out2;
1248 	scsi_scan_host(host);
1249 	return 0;
1250 
1251 out2:
1252 	list_del_init(&dev->list);
1253 	scsi_host_put(host);
1254 out1:
1255 	parport_unregister_device(dev->dev);
1256 out:
1257 	kfree(dev);
1258 	return err;
1259 }
1260 
1261 static void imm_attach(struct parport *pb)
1262 {
1263 	__imm_attach(pb);
1264 }
1265 
1266 static void imm_detach(struct parport *pb)
1267 {
1268 	imm_struct *dev;
1269 	list_for_each_entry(dev, &imm_hosts, list) {
1270 		if (dev->dev->port == pb) {
1271 			list_del_init(&dev->list);
1272 			scsi_remove_host(dev->host);
1273 			scsi_host_put(dev->host);
1274 			parport_unregister_device(dev->dev);
1275 			kfree(dev);
1276 			break;
1277 		}
1278 	}
1279 }
1280 
1281 static struct parport_driver imm_driver = {
1282 	.name	= "imm",
1283 	.attach	= imm_attach,
1284 	.detach	= imm_detach,
1285 };
1286 
1287 static int __init imm_driver_init(void)
1288 {
1289 	printk("imm: Version %s\n", IMM_VERSION);
1290 	return parport_register_driver(&imm_driver);
1291 }
1292 
1293 static void __exit imm_driver_exit(void)
1294 {
1295 	parport_unregister_driver(&imm_driver);
1296 }
1297 
1298 module_init(imm_driver_init);
1299 module_exit(imm_driver_exit);
1300 
1301 MODULE_LICENSE("GPL");
1302