xref: /openbmc/linux/drivers/scsi/imm.c (revision 93f5715e)
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 unofficial 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 <linux/slab.h>
19 #include <asm/io.h>
20 
21 #include <scsi/scsi.h>
22 #include <scsi/scsi_cmnd.h>
23 #include <scsi/scsi_device.h>
24 #include <scsi/scsi_host.h>
25 
26 /* The following #define is to avoid a clash with hosts.c */
27 #define IMM_PROBE_SPP   0x0001
28 #define IMM_PROBE_PS2   0x0002
29 #define IMM_PROBE_ECR   0x0010
30 #define IMM_PROBE_EPP17 0x0100
31 #define IMM_PROBE_EPP19 0x0200
32 
33 
34 typedef struct {
35 	struct pardevice *dev;	/* Parport device entry         */
36 	int base;		/* Actual port address          */
37 	int base_hi;		/* Hi Base address for ECP-ISA chipset */
38 	int mode;		/* Transfer mode                */
39 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
40 	struct delayed_work imm_tq;	/* Polling interrupt stuff       */
41 	unsigned long jstart;	/* Jiffies at start             */
42 	unsigned failed:1;	/* Failure flag                 */
43 	unsigned dp:1;		/* Data phase present           */
44 	unsigned rd:1;		/* Read data in data phase      */
45 	unsigned wanted:1;	/* Parport sharing busy flag    */
46 	unsigned int dev_no;	/* Device number		*/
47 	wait_queue_head_t *waiting;
48 	struct Scsi_Host *host;
49 	struct list_head list;
50 } imm_struct;
51 
52 static void imm_reset_pulse(unsigned int base);
53 static int device_check(imm_struct *dev);
54 
55 #include "imm.h"
56 
57 static inline imm_struct *imm_dev(struct Scsi_Host *host)
58 {
59 	return *(imm_struct **)&host->hostdata;
60 }
61 
62 static DEFINE_SPINLOCK(arbitration_lock);
63 
64 static void got_it(imm_struct *dev)
65 {
66 	dev->base = dev->dev->port->base;
67 	if (dev->cur_cmd)
68 		dev->cur_cmd->SCp.phase = 1;
69 	else
70 		wake_up(dev->waiting);
71 }
72 
73 static void imm_wakeup(void *ref)
74 {
75 	imm_struct *dev = (imm_struct *) ref;
76 	unsigned long flags;
77 
78 	spin_lock_irqsave(&arbitration_lock, flags);
79 	if (dev->wanted) {
80 		if (parport_claim(dev->dev) == 0) {
81 			got_it(dev);
82 			dev->wanted = 0;
83 		}
84 	}
85 	spin_unlock_irqrestore(&arbitration_lock, flags);
86 }
87 
88 static int imm_pb_claim(imm_struct *dev)
89 {
90 	unsigned long flags;
91 	int res = 1;
92 	spin_lock_irqsave(&arbitration_lock, flags);
93 	if (parport_claim(dev->dev) == 0) {
94 		got_it(dev);
95 		res = 0;
96 	}
97 	dev->wanted = res;
98 	spin_unlock_irqrestore(&arbitration_lock, flags);
99 	return res;
100 }
101 
102 static void imm_pb_dismiss(imm_struct *dev)
103 {
104 	unsigned long flags;
105 	int wanted;
106 	spin_lock_irqsave(&arbitration_lock, flags);
107 	wanted = dev->wanted;
108 	dev->wanted = 0;
109 	spin_unlock_irqrestore(&arbitration_lock, flags);
110 	if (!wanted)
111 		parport_release(dev->dev);
112 }
113 
114 static inline void imm_pb_release(imm_struct *dev)
115 {
116 	parport_release(dev->dev);
117 }
118 
119 /* This is to give the imm driver a way to modify the timings (and other
120  * parameters) by writing to the /proc/scsi/imm/0 file.
121  * Very simple method really... (Too simple, no error checking :( )
122  * Reason: Kernel hackers HATE having to unload and reload modules for
123  * testing...
124  * Also gives a method to use a script to obtain optimum timings (TODO)
125  */
126 static int imm_write_info(struct Scsi_Host *host, char *buffer, int length)
127 {
128 	imm_struct *dev = imm_dev(host);
129 
130 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
131 		dev->mode = simple_strtoul(buffer + 5, NULL, 0);
132 		return length;
133 	}
134 	printk("imm /proc: invalid variable\n");
135 	return -EINVAL;
136 }
137 
138 static int imm_show_info(struct seq_file *m, struct Scsi_Host *host)
139 {
140 	imm_struct *dev = imm_dev(host);
141 
142 	seq_printf(m, "Version : %s\n", IMM_VERSION);
143 	seq_printf(m, "Parport : %s\n", dev->dev->port->name);
144 	seq_printf(m, "Mode    : %s\n", IMM_MODE_STRING[dev->mode]);
145 	return 0;
146 }
147 
148 #if IMM_DEBUG > 0
149 #define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
150 	   y, __func__, __LINE__); imm_fail_func(x,y);
151 static inline void
152 imm_fail_func(imm_struct *dev, int error_code)
153 #else
154 static inline void
155 imm_fail(imm_struct *dev, int error_code)
156 #endif
157 {
158 	/* If we fail a device then we trash status / message bytes */
159 	if (dev->cur_cmd) {
160 		dev->cur_cmd->result = error_code << 16;
161 		dev->failed = 1;
162 	}
163 }
164 
165 /*
166  * Wait for the high bit to be set.
167  *
168  * In principle, this could be tied to an interrupt, but the adapter
169  * doesn't appear to be designed to support interrupts.  We spin on
170  * the 0x80 ready bit.
171  */
172 static unsigned char imm_wait(imm_struct *dev)
173 {
174 	int k;
175 	unsigned short ppb = dev->base;
176 	unsigned char r;
177 
178 	w_ctr(ppb, 0x0c);
179 
180 	k = IMM_SPIN_TMO;
181 	do {
182 		r = r_str(ppb);
183 		k--;
184 		udelay(1);
185 	}
186 	while (!(r & 0x80) && (k));
187 
188 	/*
189 	 * STR register (LPT base+1) to SCSI mapping:
190 	 *
191 	 * STR      imm     imm
192 	 * ===================================
193 	 * 0x80     S_REQ   S_REQ
194 	 * 0x40     !S_BSY  (????)
195 	 * 0x20     !S_CD   !S_CD
196 	 * 0x10     !S_IO   !S_IO
197 	 * 0x08     (????)  !S_BSY
198 	 *
199 	 * imm      imm     meaning
200 	 * ==================================
201 	 * 0xf0     0xb8    Bit mask
202 	 * 0xc0     0x88    ZIP wants more data
203 	 * 0xd0     0x98    ZIP wants to send more data
204 	 * 0xe0     0xa8    ZIP is expecting SCSI command data
205 	 * 0xf0     0xb8    end of transfer, ZIP is sending status
206 	 */
207 	w_ctr(ppb, 0x04);
208 	if (k)
209 		return (r & 0xb8);
210 
211 	/* Counter expired - Time out occurred */
212 	imm_fail(dev, DID_TIME_OUT);
213 	printk("imm timeout in imm_wait\n");
214 	return 0;		/* command timed out */
215 }
216 
217 static int imm_negotiate(imm_struct * tmp)
218 {
219 	/*
220 	 * The following is supposedly the IEEE 1284-1994 negotiate
221 	 * sequence. I have yet to obtain a copy of the above standard
222 	 * so this is a bit of a guess...
223 	 *
224 	 * A fair chunk of this is based on the Linux parport implementation
225 	 * of IEEE 1284.
226 	 *
227 	 * Return 0 if data available
228 	 *        1 if no data available
229 	 */
230 
231 	unsigned short base = tmp->base;
232 	unsigned char a, mode;
233 
234 	switch (tmp->mode) {
235 	case IMM_NIBBLE:
236 		mode = 0x00;
237 		break;
238 	case IMM_PS2:
239 		mode = 0x01;
240 		break;
241 	default:
242 		return 0;
243 	}
244 
245 	w_ctr(base, 0x04);
246 	udelay(5);
247 	w_dtr(base, mode);
248 	udelay(100);
249 	w_ctr(base, 0x06);
250 	udelay(5);
251 	a = (r_str(base) & 0x20) ? 0 : 1;
252 	udelay(5);
253 	w_ctr(base, 0x07);
254 	udelay(5);
255 	w_ctr(base, 0x06);
256 
257 	if (a) {
258 		printk
259 		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
260 		imm_fail(tmp, DID_ERROR);
261 	}
262 	return a;
263 }
264 
265 /*
266  * Clear EPP timeout bit.
267  */
268 static inline void epp_reset(unsigned short ppb)
269 {
270 	int i;
271 
272 	i = r_str(ppb);
273 	w_str(ppb, i);
274 	w_str(ppb, i & 0xfe);
275 }
276 
277 /*
278  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
279  */
280 static inline void ecp_sync(imm_struct *dev)
281 {
282 	int i, ppb_hi = dev->base_hi;
283 
284 	if (ppb_hi == 0)
285 		return;
286 
287 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
288 		for (i = 0; i < 100; i++) {
289 			if (r_ecr(ppb_hi) & 0x01)
290 				return;
291 			udelay(5);
292 		}
293 		printk("imm: ECP sync failed as data still present in FIFO.\n");
294 	}
295 }
296 
297 static int imm_byte_out(unsigned short base, const char *buffer, int len)
298 {
299 	int i;
300 
301 	w_ctr(base, 0x4);	/* apparently a sane mode */
302 	for (i = len >> 1; i; i--) {
303 		w_dtr(base, *buffer++);
304 		w_ctr(base, 0x5);	/* Drop STROBE low */
305 		w_dtr(base, *buffer++);
306 		w_ctr(base, 0x0);	/* STROBE high + INIT low */
307 	}
308 	w_ctr(base, 0x4);	/* apparently a sane mode */
309 	return 1;		/* All went well - we hope! */
310 }
311 
312 static int imm_nibble_in(unsigned short base, char *buffer, int len)
313 {
314 	unsigned char l;
315 	int i;
316 
317 	/*
318 	 * The following is based on documented timing signals
319 	 */
320 	w_ctr(base, 0x4);
321 	for (i = len; i; i--) {
322 		w_ctr(base, 0x6);
323 		l = (r_str(base) & 0xf0) >> 4;
324 		w_ctr(base, 0x5);
325 		*buffer++ = (r_str(base) & 0xf0) | l;
326 		w_ctr(base, 0x4);
327 	}
328 	return 1;		/* All went well - we hope! */
329 }
330 
331 static int imm_byte_in(unsigned short base, char *buffer, int len)
332 {
333 	int i;
334 
335 	/*
336 	 * The following is based on documented timing signals
337 	 */
338 	w_ctr(base, 0x4);
339 	for (i = len; i; i--) {
340 		w_ctr(base, 0x26);
341 		*buffer++ = r_dtr(base);
342 		w_ctr(base, 0x25);
343 	}
344 	return 1;		/* All went well - we hope! */
345 }
346 
347 static int imm_out(imm_struct *dev, char *buffer, int len)
348 {
349 	unsigned short ppb = dev->base;
350 	int r = imm_wait(dev);
351 
352 	/*
353 	 * Make sure that:
354 	 * a) the SCSI bus is BUSY (device still listening)
355 	 * b) the device is listening
356 	 */
357 	if ((r & 0x18) != 0x08) {
358 		imm_fail(dev, DID_ERROR);
359 		printk("IMM: returned SCSI status %2x\n", r);
360 		return 0;
361 	}
362 	switch (dev->mode) {
363 	case IMM_EPP_32:
364 	case IMM_EPP_16:
365 	case IMM_EPP_8:
366 		epp_reset(ppb);
367 		w_ctr(ppb, 0x4);
368 #ifdef CONFIG_SCSI_IZIP_EPP16
369 		if (!(((long) buffer | len) & 0x01))
370 			outsw(ppb + 4, buffer, len >> 1);
371 #else
372 		if (!(((long) buffer | len) & 0x03))
373 			outsl(ppb + 4, buffer, len >> 2);
374 #endif
375 		else
376 			outsb(ppb + 4, buffer, len);
377 		w_ctr(ppb, 0xc);
378 		r = !(r_str(ppb) & 0x01);
379 		w_ctr(ppb, 0xc);
380 		ecp_sync(dev);
381 		break;
382 
383 	case IMM_NIBBLE:
384 	case IMM_PS2:
385 		/* 8 bit output, with a loop */
386 		r = imm_byte_out(ppb, buffer, len);
387 		break;
388 
389 	default:
390 		printk("IMM: bug in imm_out()\n");
391 		r = 0;
392 	}
393 	return r;
394 }
395 
396 static int imm_in(imm_struct *dev, char *buffer, int len)
397 {
398 	unsigned short ppb = dev->base;
399 	int r = imm_wait(dev);
400 
401 	/*
402 	 * Make sure that:
403 	 * a) the SCSI bus is BUSY (device still listening)
404 	 * b) the device is sending data
405 	 */
406 	if ((r & 0x18) != 0x18) {
407 		imm_fail(dev, DID_ERROR);
408 		return 0;
409 	}
410 	switch (dev->mode) {
411 	case IMM_NIBBLE:
412 		/* 4 bit input, with a loop */
413 		r = imm_nibble_in(ppb, buffer, len);
414 		w_ctr(ppb, 0xc);
415 		break;
416 
417 	case IMM_PS2:
418 		/* 8 bit input, with a loop */
419 		r = imm_byte_in(ppb, buffer, len);
420 		w_ctr(ppb, 0xc);
421 		break;
422 
423 	case IMM_EPP_32:
424 	case IMM_EPP_16:
425 	case IMM_EPP_8:
426 		epp_reset(ppb);
427 		w_ctr(ppb, 0x24);
428 #ifdef CONFIG_SCSI_IZIP_EPP16
429 		if (!(((long) buffer | len) & 0x01))
430 			insw(ppb + 4, buffer, len >> 1);
431 #else
432 		if (!(((long) buffer | len) & 0x03))
433 			insl(ppb + 4, buffer, len >> 2);
434 #endif
435 		else
436 			insb(ppb + 4, buffer, len);
437 		w_ctr(ppb, 0x2c);
438 		r = !(r_str(ppb) & 0x01);
439 		w_ctr(ppb, 0x2c);
440 		ecp_sync(dev);
441 		break;
442 
443 	default:
444 		printk("IMM: bug in imm_ins()\n");
445 		r = 0;
446 		break;
447 	}
448 	return r;
449 }
450 
451 static int imm_cpp(unsigned short ppb, unsigned char b)
452 {
453 	/*
454 	 * Comments on udelay values refer to the
455 	 * Command Packet Protocol (CPP) timing diagram.
456 	 */
457 
458 	unsigned char s1, s2, s3;
459 	w_ctr(ppb, 0x0c);
460 	udelay(2);		/* 1 usec - infinite */
461 	w_dtr(ppb, 0xaa);
462 	udelay(10);		/* 7 usec - infinite */
463 	w_dtr(ppb, 0x55);
464 	udelay(10);		/* 7 usec - infinite */
465 	w_dtr(ppb, 0x00);
466 	udelay(10);		/* 7 usec - infinite */
467 	w_dtr(ppb, 0xff);
468 	udelay(10);		/* 7 usec - infinite */
469 	s1 = r_str(ppb) & 0xb8;
470 	w_dtr(ppb, 0x87);
471 	udelay(10);		/* 7 usec - infinite */
472 	s2 = r_str(ppb) & 0xb8;
473 	w_dtr(ppb, 0x78);
474 	udelay(10);		/* 7 usec - infinite */
475 	s3 = r_str(ppb) & 0x38;
476 	/*
477 	 * Values for b are:
478 	 * 0000 00aa    Assign address aa to current device
479 	 * 0010 00aa    Select device aa in EPP Winbond mode
480 	 * 0010 10aa    Select device aa in EPP mode
481 	 * 0011 xxxx    Deselect all devices
482 	 * 0110 00aa    Test device aa
483 	 * 1101 00aa    Select device aa in ECP mode
484 	 * 1110 00aa    Select device aa in Compatible mode
485 	 */
486 	w_dtr(ppb, b);
487 	udelay(2);		/* 1 usec - infinite */
488 	w_ctr(ppb, 0x0c);
489 	udelay(10);		/* 7 usec - infinite */
490 	w_ctr(ppb, 0x0d);
491 	udelay(2);		/* 1 usec - infinite */
492 	w_ctr(ppb, 0x0c);
493 	udelay(10);		/* 7 usec - infinite */
494 	w_dtr(ppb, 0xff);
495 	udelay(10);		/* 7 usec - infinite */
496 
497 	/*
498 	 * The following table is electrical pin values.
499 	 * (BSY is inverted at the CTR register)
500 	 *
501 	 *       BSY  ACK  POut SEL  Fault
502 	 * S1    0    X    1    1    1
503 	 * S2    1    X    0    1    1
504 	 * S3    L    X    1    1    S
505 	 *
506 	 * L => Last device in chain
507 	 * S => Selected
508 	 *
509 	 * Observered values for S1,S2,S3 are:
510 	 * Disconnect => f8/58/78
511 	 * Connect    => f8/58/70
512 	 */
513 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
514 		return 1;	/* Connected */
515 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
516 		return 0;	/* Disconnected */
517 
518 	return -1;		/* No device present */
519 }
520 
521 static inline int imm_connect(imm_struct *dev, int flag)
522 {
523 	unsigned short ppb = dev->base;
524 
525 	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
526 	imm_cpp(ppb, 0x30);	/* Disconnect all devices */
527 
528 	if ((dev->mode == IMM_EPP_8) ||
529 	    (dev->mode == IMM_EPP_16) ||
530 	    (dev->mode == IMM_EPP_32))
531 		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
532 	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
533 }
534 
535 static void imm_disconnect(imm_struct *dev)
536 {
537 	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
538 }
539 
540 static int imm_select(imm_struct *dev, int target)
541 {
542 	int k;
543 	unsigned short ppb = dev->base;
544 
545 	/*
546 	 * Firstly we want to make sure there is nothing
547 	 * holding onto the SCSI bus.
548 	 */
549 	w_ctr(ppb, 0xc);
550 
551 	k = IMM_SELECT_TMO;
552 	do {
553 		k--;
554 	} while ((r_str(ppb) & 0x08) && (k));
555 
556 	if (!k)
557 		return 0;
558 
559 	/*
560 	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
561 	 */
562 	w_ctr(ppb, 0x4);
563 	w_dtr(ppb, 0x80 | (1 << target));
564 	udelay(1);
565 
566 	/*
567 	 * Deassert SELIN first followed by STROBE
568 	 */
569 	w_ctr(ppb, 0xc);
570 	w_ctr(ppb, 0xd);
571 
572 	/*
573 	 * ACK should drop low while SELIN is deasserted.
574 	 * FAULT should drop low when the SCSI device latches the bus.
575 	 */
576 	k = IMM_SELECT_TMO;
577 	do {
578 		k--;
579 	}
580 	while (!(r_str(ppb) & 0x08) && (k));
581 
582 	/*
583 	 * Place the interface back into a sane state (status mode)
584 	 */
585 	w_ctr(ppb, 0xc);
586 	return (k) ? 1 : 0;
587 }
588 
589 static int imm_init(imm_struct *dev)
590 {
591 	if (imm_connect(dev, 0) != 1)
592 		return -EIO;
593 	imm_reset_pulse(dev->base);
594 	mdelay(1);	/* Delay to allow devices to settle */
595 	imm_disconnect(dev);
596 	mdelay(1);	/* Another delay to allow devices to settle */
597 	return device_check(dev);
598 }
599 
600 static inline int imm_send_command(struct scsi_cmnd *cmd)
601 {
602 	imm_struct *dev = imm_dev(cmd->device->host);
603 	int k;
604 
605 	/* NOTE: IMM uses byte pairs */
606 	for (k = 0; k < cmd->cmd_len; k += 2)
607 		if (!imm_out(dev, &cmd->cmnd[k], 2))
608 			return 0;
609 	return 1;
610 }
611 
612 /*
613  * The bulk flag enables some optimisations in the data transfer loops,
614  * it should be true for any command that transfers data in integral
615  * numbers of sectors.
616  *
617  * The driver appears to remain stable if we speed up the parallel port
618  * i/o in this function, but not elsewhere.
619  */
620 static int imm_completion(struct scsi_cmnd *cmd)
621 {
622 	/* Return codes:
623 	 * -1     Error
624 	 *  0     Told to schedule
625 	 *  1     Finished data transfer
626 	 */
627 	imm_struct *dev = imm_dev(cmd->device->host);
628 	unsigned short ppb = dev->base;
629 	unsigned long start_jiffies = jiffies;
630 
631 	unsigned char r, v;
632 	int fast, bulk, status;
633 
634 	v = cmd->cmnd[0];
635 	bulk = ((v == READ_6) ||
636 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
637 
638 	/*
639 	 * We only get here if the drive is ready to comunicate,
640 	 * hence no need for a full imm_wait.
641 	 */
642 	w_ctr(ppb, 0x0c);
643 	r = (r_str(ppb) & 0xb8);
644 
645 	/*
646 	 * while (device is not ready to send status byte)
647 	 *     loop;
648 	 */
649 	while (r != (unsigned char) 0xb8) {
650 		/*
651 		 * If we have been running for more than a full timer tick
652 		 * then take a rest.
653 		 */
654 		if (time_after(jiffies, start_jiffies + 1))
655 			return 0;
656 
657 		/*
658 		 * FAIL if:
659 		 * a) Drive status is screwy (!ready && !present)
660 		 * b) Drive is requesting/sending more data than expected
661 		 */
662 		if (((r & 0x88) != 0x88) || (cmd->SCp.this_residual <= 0)) {
663 			imm_fail(dev, DID_ERROR);
664 			return -1;	/* ERROR_RETURN */
665 		}
666 		/* determine if we should use burst I/O */
667 		if (dev->rd == 0) {
668 			fast = (bulk
669 				&& (cmd->SCp.this_residual >=
670 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 2;
671 			status = imm_out(dev, cmd->SCp.ptr, fast);
672 		} else {
673 			fast = (bulk
674 				&& (cmd->SCp.this_residual >=
675 				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 1;
676 			status = imm_in(dev, cmd->SCp.ptr, fast);
677 		}
678 
679 		cmd->SCp.ptr += fast;
680 		cmd->SCp.this_residual -= fast;
681 
682 		if (!status) {
683 			imm_fail(dev, DID_BUS_BUSY);
684 			return -1;	/* ERROR_RETURN */
685 		}
686 		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
687 			/* if scatter/gather, advance to the next segment */
688 			if (cmd->SCp.buffers_residual--) {
689 				cmd->SCp.buffer++;
690 				cmd->SCp.this_residual =
691 				    cmd->SCp.buffer->length;
692 				cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
693 
694 				/*
695 				 * Make sure that we transfer even number of bytes
696 				 * otherwise it makes imm_byte_out() messy.
697 				 */
698 				if (cmd->SCp.this_residual & 0x01)
699 					cmd->SCp.this_residual++;
700 			}
701 		}
702 		/* Now check to see if the drive is ready to comunicate */
703 		w_ctr(ppb, 0x0c);
704 		r = (r_str(ppb) & 0xb8);
705 
706 		/* If not, drop back down to the scheduler and wait a timer tick */
707 		if (!(r & 0x80))
708 			return 0;
709 	}
710 	return 1;		/* FINISH_RETURN */
711 }
712 
713 /*
714  * Since the IMM itself doesn't generate interrupts, we use
715  * the scheduler's task queue to generate a stream of call-backs and
716  * complete the request when the drive is ready.
717  */
718 static void imm_interrupt(struct work_struct *work)
719 {
720 	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
721 	struct scsi_cmnd *cmd = dev->cur_cmd;
722 	struct Scsi_Host *host = cmd->device->host;
723 	unsigned long flags;
724 
725 	if (imm_engine(dev, cmd)) {
726 		schedule_delayed_work(&dev->imm_tq, 1);
727 		return;
728 	}
729 	/* Command must of completed hence it is safe to let go... */
730 #if IMM_DEBUG > 0
731 	switch ((cmd->result >> 16) & 0xff) {
732 	case DID_OK:
733 		break;
734 	case DID_NO_CONNECT:
735 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
736 		break;
737 	case DID_BUS_BUSY:
738 		printk("imm: BUS BUSY - EPP timeout detected\n");
739 		break;
740 	case DID_TIME_OUT:
741 		printk("imm: unknown timeout\n");
742 		break;
743 	case DID_ABORT:
744 		printk("imm: told to abort\n");
745 		break;
746 	case DID_PARITY:
747 		printk("imm: parity error (???)\n");
748 		break;
749 	case DID_ERROR:
750 		printk("imm: internal driver error\n");
751 		break;
752 	case DID_RESET:
753 		printk("imm: told to reset device\n");
754 		break;
755 	case DID_BAD_INTR:
756 		printk("imm: bad interrupt (???)\n");
757 		break;
758 	default:
759 		printk("imm: bad return code (%02x)\n",
760 		       (cmd->result >> 16) & 0xff);
761 	}
762 #endif
763 
764 	if (cmd->SCp.phase > 1)
765 		imm_disconnect(dev);
766 
767 	imm_pb_dismiss(dev);
768 
769 	spin_lock_irqsave(host->host_lock, flags);
770 	dev->cur_cmd = NULL;
771 	cmd->scsi_done(cmd);
772 	spin_unlock_irqrestore(host->host_lock, flags);
773 	return;
774 }
775 
776 static int imm_engine(imm_struct *dev, struct scsi_cmnd *cmd)
777 {
778 	unsigned short ppb = dev->base;
779 	unsigned char l = 0, h = 0;
780 	int retv, x;
781 
782 	/* First check for any errors that may have occurred
783 	 * Here we check for internal errors
784 	 */
785 	if (dev->failed)
786 		return 0;
787 
788 	switch (cmd->SCp.phase) {
789 	case 0:		/* Phase 0 - Waiting for parport */
790 		if (time_after(jiffies, dev->jstart + HZ)) {
791 			/*
792 			 * We waited more than a second
793 			 * for parport to call us
794 			 */
795 			imm_fail(dev, DID_BUS_BUSY);
796 			return 0;
797 		}
798 		return 1;	/* wait until imm_wakeup claims parport */
799 		/* Phase 1 - Connected */
800 	case 1:
801 		imm_connect(dev, CONNECT_EPP_MAYBE);
802 		cmd->SCp.phase++;
803 
804 		/* Phase 2 - We are now talking to the scsi bus */
805 	case 2:
806 		if (!imm_select(dev, scmd_id(cmd))) {
807 			imm_fail(dev, DID_NO_CONNECT);
808 			return 0;
809 		}
810 		cmd->SCp.phase++;
811 
812 		/* Phase 3 - Ready to accept a command */
813 	case 3:
814 		w_ctr(ppb, 0x0c);
815 		if (!(r_str(ppb) & 0x80))
816 			return 1;
817 
818 		if (!imm_send_command(cmd))
819 			return 0;
820 		cmd->SCp.phase++;
821 
822 		/* Phase 4 - Setup scatter/gather buffers */
823 	case 4:
824 		if (scsi_bufflen(cmd)) {
825 			cmd->SCp.buffer = scsi_sglist(cmd);
826 			cmd->SCp.this_residual = cmd->SCp.buffer->length;
827 			cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
828 		} else {
829 			cmd->SCp.buffer = NULL;
830 			cmd->SCp.this_residual = 0;
831 			cmd->SCp.ptr = NULL;
832 		}
833 		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
834 		cmd->SCp.phase++;
835 		if (cmd->SCp.this_residual & 0x01)
836 			cmd->SCp.this_residual++;
837 		/* Phase 5 - Pre-Data transfer stage */
838 	case 5:
839 		/* Spin lock for BUSY */
840 		w_ctr(ppb, 0x0c);
841 		if (!(r_str(ppb) & 0x80))
842 			return 1;
843 
844 		/* Require negotiation for read requests */
845 		x = (r_str(ppb) & 0xb8);
846 		dev->rd = (x & 0x10) ? 1 : 0;
847 		dev->dp = (x & 0x20) ? 0 : 1;
848 
849 		if ((dev->dp) && (dev->rd))
850 			if (imm_negotiate(dev))
851 				return 0;
852 		cmd->SCp.phase++;
853 
854 		/* Phase 6 - Data transfer stage */
855 	case 6:
856 		/* Spin lock for BUSY */
857 		w_ctr(ppb, 0x0c);
858 		if (!(r_str(ppb) & 0x80))
859 			return 1;
860 
861 		if (dev->dp) {
862 			retv = imm_completion(cmd);
863 			if (retv == -1)
864 				return 0;
865 			if (retv == 0)
866 				return 1;
867 		}
868 		cmd->SCp.phase++;
869 
870 		/* Phase 7 - Post data transfer stage */
871 	case 7:
872 		if ((dev->dp) && (dev->rd)) {
873 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
874 				w_ctr(ppb, 0x4);
875 				w_ctr(ppb, 0xc);
876 				w_ctr(ppb, 0xe);
877 				w_ctr(ppb, 0x4);
878 			}
879 		}
880 		cmd->SCp.phase++;
881 
882 		/* Phase 8 - Read status/message */
883 	case 8:
884 		/* Check for data overrun */
885 		if (imm_wait(dev) != (unsigned char) 0xb8) {
886 			imm_fail(dev, DID_ERROR);
887 			return 0;
888 		}
889 		if (imm_negotiate(dev))
890 			return 0;
891 		if (imm_in(dev, &l, 1)) {	/* read status byte */
892 			/* Check for optional message byte */
893 			if (imm_wait(dev) == (unsigned char) 0xb8)
894 				imm_in(dev, &h, 1);
895 			cmd->result = (DID_OK << 16) | (l & STATUS_MASK);
896 		}
897 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
898 			w_ctr(ppb, 0x4);
899 			w_ctr(ppb, 0xc);
900 			w_ctr(ppb, 0xe);
901 			w_ctr(ppb, 0x4);
902 		}
903 		return 0;	/* Finished */
904 		break;
905 
906 	default:
907 		printk("imm: Invalid scsi phase\n");
908 	}
909 	return 0;
910 }
911 
912 static int imm_queuecommand_lck(struct scsi_cmnd *cmd,
913 		void (*done)(struct scsi_cmnd *))
914 {
915 	imm_struct *dev = imm_dev(cmd->device->host);
916 
917 	if (dev->cur_cmd) {
918 		printk("IMM: bug in imm_queuecommand\n");
919 		return 0;
920 	}
921 	dev->failed = 0;
922 	dev->jstart = jiffies;
923 	dev->cur_cmd = cmd;
924 	cmd->scsi_done = done;
925 	cmd->result = DID_ERROR << 16;	/* default return code */
926 	cmd->SCp.phase = 0;	/* bus free */
927 
928 	schedule_delayed_work(&dev->imm_tq, 0);
929 
930 	imm_pb_claim(dev);
931 
932 	return 0;
933 }
934 
935 static DEF_SCSI_QCMD(imm_queuecommand)
936 
937 /*
938  * Apparently the disk->capacity attribute is off by 1 sector
939  * for all disk drives.  We add the one here, but it should really
940  * be done in sd.c.  Even if it gets fixed there, this will still
941  * work.
942  */
943 static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
944 			 sector_t capacity, int ip[])
945 {
946 	ip[0] = 0x40;
947 	ip[1] = 0x20;
948 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
949 	if (ip[2] > 1024) {
950 		ip[0] = 0xff;
951 		ip[1] = 0x3f;
952 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
953 	}
954 	return 0;
955 }
956 
957 static int imm_abort(struct scsi_cmnd *cmd)
958 {
959 	imm_struct *dev = imm_dev(cmd->device->host);
960 	/*
961 	 * There is no method for aborting commands since Iomega
962 	 * have tied the SCSI_MESSAGE line high in the interface
963 	 */
964 
965 	switch (cmd->SCp.phase) {
966 	case 0:		/* Do not have access to parport */
967 	case 1:		/* Have not connected to interface */
968 		dev->cur_cmd = NULL;	/* Forget the problem */
969 		return SUCCESS;
970 		break;
971 	default:		/* SCSI command sent, can not abort */
972 		return FAILED;
973 		break;
974 	}
975 }
976 
977 static void imm_reset_pulse(unsigned int base)
978 {
979 	w_ctr(base, 0x04);
980 	w_dtr(base, 0x40);
981 	udelay(1);
982 	w_ctr(base, 0x0c);
983 	w_ctr(base, 0x0d);
984 	udelay(50);
985 	w_ctr(base, 0x0c);
986 	w_ctr(base, 0x04);
987 }
988 
989 static int imm_reset(struct scsi_cmnd *cmd)
990 {
991 	imm_struct *dev = imm_dev(cmd->device->host);
992 
993 	if (cmd->SCp.phase)
994 		imm_disconnect(dev);
995 	dev->cur_cmd = NULL;	/* Forget the problem */
996 
997 	imm_connect(dev, CONNECT_NORMAL);
998 	imm_reset_pulse(dev->base);
999 	mdelay(1);		/* device settle delay */
1000 	imm_disconnect(dev);
1001 	mdelay(1);		/* device settle delay */
1002 	return SUCCESS;
1003 }
1004 
1005 static int device_check(imm_struct *dev)
1006 {
1007 	/* This routine looks for a device and then attempts to use EPP
1008 	   to send a command. If all goes as planned then EPP is available. */
1009 
1010 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1011 	int loop, old_mode, status, k, ppb = dev->base;
1012 	unsigned char l;
1013 
1014 	old_mode = dev->mode;
1015 	for (loop = 0; loop < 8; loop++) {
1016 		/* Attempt to use EPP for Test Unit Ready */
1017 		if ((ppb & 0x0007) == 0x0000)
1018 			dev->mode = IMM_EPP_32;
1019 
1020 	      second_pass:
1021 		imm_connect(dev, CONNECT_EPP_MAYBE);
1022 		/* Select SCSI device */
1023 		if (!imm_select(dev, loop)) {
1024 			imm_disconnect(dev);
1025 			continue;
1026 		}
1027 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1028 		       loop, IMM_MODE_STRING[dev->mode]);
1029 
1030 		/* Send SCSI command */
1031 		status = 1;
1032 		w_ctr(ppb, 0x0c);
1033 		for (l = 0; (l < 3) && (status); l++)
1034 			status = imm_out(dev, &cmd[l << 1], 2);
1035 
1036 		if (!status) {
1037 			imm_disconnect(dev);
1038 			imm_connect(dev, CONNECT_EPP_MAYBE);
1039 			imm_reset_pulse(dev->base);
1040 			udelay(1000);
1041 			imm_disconnect(dev);
1042 			udelay(1000);
1043 			if (dev->mode == IMM_EPP_32) {
1044 				dev->mode = old_mode;
1045 				goto second_pass;
1046 			}
1047 			printk("imm: Unable to establish communication\n");
1048 			return -EIO;
1049 		}
1050 		w_ctr(ppb, 0x0c);
1051 
1052 		k = 1000000;	/* 1 Second */
1053 		do {
1054 			l = r_str(ppb);
1055 			k--;
1056 			udelay(1);
1057 		} while (!(l & 0x80) && (k));
1058 
1059 		l &= 0xb8;
1060 
1061 		if (l != 0xb8) {
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
1073 			    ("imm: Unable to establish communication\n");
1074 			return -EIO;
1075 		}
1076 		imm_disconnect(dev);
1077 		printk
1078 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1079 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1080 		imm_connect(dev, CONNECT_EPP_MAYBE);
1081 		imm_reset_pulse(dev->base);
1082 		udelay(1000);
1083 		imm_disconnect(dev);
1084 		udelay(1000);
1085 		return 0;
1086 	}
1087 	printk("imm: No devices found\n");
1088 	return -ENODEV;
1089 }
1090 
1091 /*
1092  * imm cannot deal with highmem, so this causes all IO pages for this host
1093  * to reside in low memory (hence mapped)
1094  */
1095 static int imm_adjust_queue(struct scsi_device *device)
1096 {
1097 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1098 	return 0;
1099 }
1100 
1101 static struct scsi_host_template imm_template = {
1102 	.module			= THIS_MODULE,
1103 	.proc_name		= "imm",
1104 	.show_info		= imm_show_info,
1105 	.write_info		= imm_write_info,
1106 	.name			= "Iomega VPI2 (imm) interface",
1107 	.queuecommand		= imm_queuecommand,
1108 	.eh_abort_handler	= imm_abort,
1109 	.eh_host_reset_handler	= imm_reset,
1110 	.bios_param		= imm_biosparam,
1111 	.this_id		= 7,
1112 	.sg_tablesize		= SG_ALL,
1113 	.use_clustering		= ENABLE_CLUSTERING,
1114 	.can_queue		= 1,
1115 	.slave_alloc		= imm_adjust_queue,
1116 };
1117 
1118 /***************************************************************************
1119  *                   Parallel port probing routines                        *
1120  ***************************************************************************/
1121 
1122 static LIST_HEAD(imm_hosts);
1123 
1124 /*
1125  * Finds the first available device number that can be alloted to the
1126  * new imm device and returns the address of the previous node so that
1127  * we can add to the tail and have a list in the ascending order.
1128  */
1129 
1130 static inline imm_struct *find_parent(void)
1131 {
1132 	imm_struct *dev, *par = NULL;
1133 	unsigned int cnt = 0;
1134 
1135 	if (list_empty(&imm_hosts))
1136 		return NULL;
1137 
1138 	list_for_each_entry(dev, &imm_hosts, list) {
1139 		if (dev->dev_no != cnt)
1140 			return par;
1141 		cnt++;
1142 		par = dev;
1143 	}
1144 
1145 	return par;
1146 }
1147 
1148 static int __imm_attach(struct parport *pb)
1149 {
1150 	struct Scsi_Host *host;
1151 	imm_struct *dev, *temp;
1152 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1153 	DEFINE_WAIT(wait);
1154 	int ports;
1155 	int modes, ppb;
1156 	int err = -ENOMEM;
1157 	struct pardev_cb imm_cb;
1158 
1159 	init_waitqueue_head(&waiting);
1160 
1161 	dev = kzalloc(sizeof(imm_struct), GFP_KERNEL);
1162 	if (!dev)
1163 		return -ENOMEM;
1164 
1165 
1166 	dev->base = -1;
1167 	dev->mode = IMM_AUTODETECT;
1168 	INIT_LIST_HEAD(&dev->list);
1169 
1170 	temp = find_parent();
1171 	if (temp)
1172 		dev->dev_no = temp->dev_no + 1;
1173 
1174 	memset(&imm_cb, 0, sizeof(imm_cb));
1175 	imm_cb.private = dev;
1176 	imm_cb.wakeup = imm_wakeup;
1177 
1178 	dev->dev = parport_register_dev_model(pb, "imm", &imm_cb, dev->dev_no);
1179 	if (!dev->dev)
1180 		goto out;
1181 
1182 
1183 	/* Claim the bus so it remembers what we do to the control
1184 	 * registers. [ CTR and ECP ]
1185 	 */
1186 	err = -EBUSY;
1187 	dev->waiting = &waiting;
1188 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1189 	if (imm_pb_claim(dev))
1190 		schedule_timeout(3 * HZ);
1191 	if (dev->wanted) {
1192 		printk(KERN_ERR "imm%d: failed to claim parport because "
1193 			"a pardevice is owning the port for too long "
1194 			"time!\n", pb->number);
1195 		imm_pb_dismiss(dev);
1196 		dev->waiting = NULL;
1197 		finish_wait(&waiting, &wait);
1198 		goto out1;
1199 	}
1200 	dev->waiting = NULL;
1201 	finish_wait(&waiting, &wait);
1202 	ppb = dev->base = dev->dev->port->base;
1203 	dev->base_hi = dev->dev->port->base_hi;
1204 	w_ctr(ppb, 0x0c);
1205 	modes = dev->dev->port->modes;
1206 
1207 	/* Mode detection works up the chain of speed
1208 	 * This avoids a nasty if-then-else-if-... tree
1209 	 */
1210 	dev->mode = IMM_NIBBLE;
1211 
1212 	if (modes & PARPORT_MODE_TRISTATE)
1213 		dev->mode = IMM_PS2;
1214 
1215 	/* Done configuration */
1216 
1217 	err = imm_init(dev);
1218 
1219 	imm_pb_release(dev);
1220 
1221 	if (err)
1222 		goto out1;
1223 
1224 	/* now the glue ... */
1225 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1226 		ports = 3;
1227 	else
1228 		ports = 8;
1229 
1230 	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1231 
1232 	err = -ENOMEM;
1233 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1234 	if (!host)
1235 		goto out1;
1236 	host->io_port = pb->base;
1237 	host->n_io_port = ports;
1238 	host->dma_channel = -1;
1239 	host->unique_id = pb->number;
1240 	*(imm_struct **)&host->hostdata = dev;
1241 	dev->host = host;
1242 	if (!temp)
1243 		list_add_tail(&dev->list, &imm_hosts);
1244 	else
1245 		list_add_tail(&dev->list, &temp->list);
1246 	err = scsi_add_host(host, NULL);
1247 	if (err)
1248 		goto out2;
1249 	scsi_scan_host(host);
1250 	return 0;
1251 
1252 out2:
1253 	list_del_init(&dev->list);
1254 	scsi_host_put(host);
1255 out1:
1256 	parport_unregister_device(dev->dev);
1257 out:
1258 	kfree(dev);
1259 	return err;
1260 }
1261 
1262 static void imm_attach(struct parport *pb)
1263 {
1264 	__imm_attach(pb);
1265 }
1266 
1267 static void imm_detach(struct parport *pb)
1268 {
1269 	imm_struct *dev;
1270 	list_for_each_entry(dev, &imm_hosts, list) {
1271 		if (dev->dev->port == pb) {
1272 			list_del_init(&dev->list);
1273 			scsi_remove_host(dev->host);
1274 			scsi_host_put(dev->host);
1275 			parport_unregister_device(dev->dev);
1276 			kfree(dev);
1277 			break;
1278 		}
1279 	}
1280 }
1281 
1282 static struct parport_driver imm_driver = {
1283 	.name		= "imm",
1284 	.match_port	= imm_attach,
1285 	.detach		= imm_detach,
1286 	.devmodel	= true,
1287 };
1288 
1289 static int __init imm_driver_init(void)
1290 {
1291 	printk("imm: Version %s\n", IMM_VERSION);
1292 	return parport_register_driver(&imm_driver);
1293 }
1294 
1295 static void __exit imm_driver_exit(void)
1296 {
1297 	parport_unregister_driver(&imm_driver);
1298 }
1299 
1300 module_init(imm_driver_init);
1301 module_exit(imm_driver_exit);
1302 
1303 MODULE_LICENSE("GPL");
1304