xref: /linux/drivers/scsi/imm.c (revision 5cd2340cb6a383d04fd88e48fabc2a21a909d6a1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* imm.c   --  low level driver for the IOMEGA MatchMaker
3  * parallel port SCSI host adapter.
4  *
5  * (The IMM is the embedded controller in the ZIP Plus drive.)
6  *
7  * My unofficial company acronym list is 21 pages long:
8  *      FLA:    Four letter acronym with built in facility for
9  *              future expansion to five letters.
10  */
11 
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/blkdev.h>
16 #include <linux/parport.h>
17 #include <linux/workqueue.h>
18 #include <linux/delay.h>
19 #include <linux/slab.h>
20 #include <asm/io.h>
21 
22 #include <scsi/scsi.h>
23 #include <scsi/scsi_cmnd.h>
24 #include <scsi/scsi_device.h>
25 #include <scsi/scsi_host.h>
26 
27 /* The following #define is to avoid a clash with hosts.c */
28 #define IMM_PROBE_SPP   0x0001
29 #define IMM_PROBE_PS2   0x0002
30 #define IMM_PROBE_ECR   0x0010
31 #define IMM_PROBE_EPP17 0x0100
32 #define IMM_PROBE_EPP19 0x0200
33 
34 
35 typedef struct {
36 	struct pardevice *dev;	/* Parport device entry         */
37 	int base;		/* Actual port address          */
38 	int base_hi;		/* Hi Base address for ECP-ISA chipset */
39 	int mode;		/* Transfer mode                */
40 	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
41 	struct delayed_work imm_tq;	/* Polling interrupt stuff       */
42 	unsigned long jstart;	/* Jiffies at start             */
43 	unsigned failed:1;	/* Failure flag                 */
44 	unsigned dp:1;		/* Data phase present           */
45 	unsigned rd:1;		/* Read data in data phase      */
46 	unsigned wanted:1;	/* Parport sharing busy flag    */
47 	unsigned int dev_no;	/* Device number		*/
48 	wait_queue_head_t *waiting;
49 	struct Scsi_Host *host;
50 	struct list_head list;
51 } imm_struct;
52 
53 static void imm_reset_pulse(unsigned int base);
54 static int device_check(imm_struct *dev, bool autodetect);
55 
56 #include "imm.h"
57 
58 static unsigned int mode = IMM_AUTODETECT;
59 module_param(mode, uint, 0644);
60 MODULE_PARM_DESC(mode, "Transfer mode (0 = Autodetect, 1 = SPP 4-bit, "
61 	"2 = SPP 8-bit, 3 = EPP 8-bit, 4 = EPP 16-bit, 5 = EPP 32-bit");
62 
63 static inline imm_struct *imm_dev(struct Scsi_Host *host)
64 {
65 	return *(imm_struct **)&host->hostdata;
66 }
67 
68 static DEFINE_SPINLOCK(arbitration_lock);
69 
70 static void got_it(imm_struct *dev)
71 {
72 	dev->base = dev->dev->port->base;
73 	if (dev->cur_cmd)
74 		imm_scsi_pointer(dev->cur_cmd)->phase = 1;
75 	else
76 		wake_up(dev->waiting);
77 }
78 
79 static void imm_wakeup(void *ref)
80 {
81 	imm_struct *dev = (imm_struct *) ref;
82 	unsigned long flags;
83 
84 	spin_lock_irqsave(&arbitration_lock, flags);
85 	if (dev->wanted) {
86 		if (parport_claim(dev->dev) == 0) {
87 			got_it(dev);
88 			dev->wanted = 0;
89 		}
90 	}
91 	spin_unlock_irqrestore(&arbitration_lock, flags);
92 }
93 
94 static int imm_pb_claim(imm_struct *dev)
95 {
96 	unsigned long flags;
97 	int res = 1;
98 	spin_lock_irqsave(&arbitration_lock, flags);
99 	if (parport_claim(dev->dev) == 0) {
100 		got_it(dev);
101 		res = 0;
102 	}
103 	dev->wanted = res;
104 	spin_unlock_irqrestore(&arbitration_lock, flags);
105 	return res;
106 }
107 
108 static void imm_pb_dismiss(imm_struct *dev)
109 {
110 	unsigned long flags;
111 	int wanted;
112 	spin_lock_irqsave(&arbitration_lock, flags);
113 	wanted = dev->wanted;
114 	dev->wanted = 0;
115 	spin_unlock_irqrestore(&arbitration_lock, flags);
116 	if (!wanted)
117 		parport_release(dev->dev);
118 }
119 
120 static inline void imm_pb_release(imm_struct *dev)
121 {
122 	parport_release(dev->dev);
123 }
124 
125 /* This is to give the imm driver a way to modify the timings (and other
126  * parameters) by writing to the /proc/scsi/imm/0 file.
127  * Very simple method really... (Too simple, no error checking :( )
128  * Reason: Kernel hackers HATE having to unload and reload modules for
129  * testing...
130  * Also gives a method to use a script to obtain optimum timings (TODO)
131  */
132 static int imm_write_info(struct Scsi_Host *host, char *buffer, int length)
133 {
134 	imm_struct *dev = imm_dev(host);
135 
136 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
137 		dev->mode = simple_strtoul(buffer + 5, NULL, 0);
138 		return length;
139 	}
140 	printk("imm /proc: invalid variable\n");
141 	return -EINVAL;
142 }
143 
144 static int imm_show_info(struct seq_file *m, struct Scsi_Host *host)
145 {
146 	imm_struct *dev = imm_dev(host);
147 
148 	seq_printf(m, "Version : %s\n", IMM_VERSION);
149 	seq_printf(m, "Parport : %s\n", dev->dev->port->name);
150 	seq_printf(m, "Mode    : %s\n", IMM_MODE_STRING[dev->mode]);
151 	return 0;
152 }
153 
154 #if IMM_DEBUG > 0
155 #define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
156 	   y, __func__, __LINE__); imm_fail_func(x,y);
157 static inline void
158 imm_fail_func(imm_struct *dev, int error_code)
159 #else
160 static inline void
161 imm_fail(imm_struct *dev, int error_code)
162 #endif
163 {
164 	/* If we fail a device then we trash status / message bytes */
165 	if (dev->cur_cmd) {
166 		dev->cur_cmd->result = error_code << 16;
167 		dev->failed = 1;
168 	}
169 }
170 
171 /*
172  * Wait for the high bit to be set.
173  *
174  * In principle, this could be tied to an interrupt, but the adapter
175  * doesn't appear to be designed to support interrupts.  We spin on
176  * the 0x80 ready bit.
177  */
178 static unsigned char imm_wait(imm_struct *dev)
179 {
180 	int k;
181 	unsigned short ppb = dev->base;
182 	unsigned char r;
183 
184 	w_ctr(ppb, 0x0c);
185 
186 	k = IMM_SPIN_TMO;
187 	do {
188 		r = r_str(ppb);
189 		k--;
190 		udelay(1);
191 	}
192 	while (!(r & 0x80) && (k));
193 
194 	/*
195 	 * STR register (LPT base+1) to SCSI mapping:
196 	 *
197 	 * STR      imm     imm
198 	 * ===================================
199 	 * 0x80     S_REQ   S_REQ
200 	 * 0x40     !S_BSY  (????)
201 	 * 0x20     !S_CD   !S_CD
202 	 * 0x10     !S_IO   !S_IO
203 	 * 0x08     (????)  !S_BSY
204 	 *
205 	 * imm      imm     meaning
206 	 * ==================================
207 	 * 0xf0     0xb8    Bit mask
208 	 * 0xc0     0x88    ZIP wants more data
209 	 * 0xd0     0x98    ZIP wants to send more data
210 	 * 0xe0     0xa8    ZIP is expecting SCSI command data
211 	 * 0xf0     0xb8    end of transfer, ZIP is sending status
212 	 */
213 	w_ctr(ppb, 0x04);
214 	if (k)
215 		return (r & 0xb8);
216 
217 	/* Counter expired - Time out occurred */
218 	imm_fail(dev, DID_TIME_OUT);
219 	printk("imm timeout in imm_wait\n");
220 	return 0;		/* command timed out */
221 }
222 
223 static int imm_negotiate(imm_struct * tmp)
224 {
225 	/*
226 	 * The following is supposedly the IEEE 1284-1994 negotiate
227 	 * sequence. I have yet to obtain a copy of the above standard
228 	 * so this is a bit of a guess...
229 	 *
230 	 * A fair chunk of this is based on the Linux parport implementation
231 	 * of IEEE 1284.
232 	 *
233 	 * Return 0 if data available
234 	 *        1 if no data available
235 	 */
236 
237 	unsigned short base = tmp->base;
238 	unsigned char a, mode;
239 
240 	switch (tmp->mode) {
241 	case IMM_NIBBLE:
242 		mode = 0x00;
243 		break;
244 	case IMM_PS2:
245 		mode = 0x01;
246 		break;
247 	default:
248 		return 0;
249 	}
250 
251 	w_ctr(base, 0x04);
252 	udelay(5);
253 	w_dtr(base, mode);
254 	udelay(100);
255 	w_ctr(base, 0x06);
256 	udelay(5);
257 	a = (r_str(base) & 0x20) ? 0 : 1;
258 	udelay(5);
259 	w_ctr(base, 0x07);
260 	udelay(5);
261 	w_ctr(base, 0x06);
262 
263 	if (a) {
264 		printk
265 		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
266 		imm_fail(tmp, DID_ERROR);
267 	}
268 	return a;
269 }
270 
271 /*
272  * Clear EPP timeout bit.
273  */
274 static inline void epp_reset(unsigned short ppb)
275 {
276 	int i;
277 
278 	i = r_str(ppb);
279 	w_str(ppb, i);
280 	w_str(ppb, i & 0xfe);
281 }
282 
283 /*
284  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
285  */
286 static inline void ecp_sync(imm_struct *dev)
287 {
288 	int i, ppb_hi = dev->base_hi;
289 
290 	if (ppb_hi == 0)
291 		return;
292 
293 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
294 		for (i = 0; i < 100; i++) {
295 			if (r_ecr(ppb_hi) & 0x01)
296 				return;
297 			udelay(5);
298 		}
299 		printk("imm: ECP sync failed as data still present in FIFO.\n");
300 	}
301 }
302 
303 static int imm_byte_out(unsigned short base, const char *buffer, int len)
304 {
305 	int i;
306 
307 	w_ctr(base, 0x4);	/* apparently a sane mode */
308 	for (i = len >> 1; i; i--) {
309 		w_dtr(base, *buffer++);
310 		w_ctr(base, 0x5);	/* Drop STROBE low */
311 		w_dtr(base, *buffer++);
312 		w_ctr(base, 0x0);	/* STROBE high + INIT low */
313 	}
314 	w_ctr(base, 0x4);	/* apparently a sane mode */
315 	return 1;		/* All went well - we hope! */
316 }
317 
318 static int imm_nibble_in(unsigned short base, char *buffer, int len)
319 {
320 	unsigned char l;
321 	int i;
322 
323 	/*
324 	 * The following is based on documented timing signals
325 	 */
326 	w_ctr(base, 0x4);
327 	for (i = len; i; i--) {
328 		w_ctr(base, 0x6);
329 		l = (r_str(base) & 0xf0) >> 4;
330 		w_ctr(base, 0x5);
331 		*buffer++ = (r_str(base) & 0xf0) | l;
332 		w_ctr(base, 0x4);
333 	}
334 	return 1;		/* All went well - we hope! */
335 }
336 
337 static int imm_byte_in(unsigned short base, char *buffer, int len)
338 {
339 	int i;
340 
341 	/*
342 	 * The following is based on documented timing signals
343 	 */
344 	w_ctr(base, 0x4);
345 	for (i = len; i; i--) {
346 		w_ctr(base, 0x26);
347 		*buffer++ = r_dtr(base);
348 		w_ctr(base, 0x25);
349 	}
350 	return 1;		/* All went well - we hope! */
351 }
352 
353 static int imm_out(imm_struct *dev, char *buffer, int len)
354 {
355 	unsigned short ppb = dev->base;
356 	int r = imm_wait(dev);
357 
358 	/*
359 	 * Make sure that:
360 	 * a) the SCSI bus is BUSY (device still listening)
361 	 * b) the device is listening
362 	 */
363 	if ((r & 0x18) != 0x08) {
364 		imm_fail(dev, DID_ERROR);
365 		printk("IMM: returned SCSI status %2x\n", r);
366 		return 0;
367 	}
368 	switch (dev->mode) {
369 	case IMM_EPP_32:
370 	case IMM_EPP_16:
371 	case IMM_EPP_8:
372 		epp_reset(ppb);
373 		w_ctr(ppb, 0x4);
374 		if (dev->mode == IMM_EPP_32 && !(((long) buffer | len) & 0x03))
375 			outsl(ppb + 4, buffer, len >> 2);
376 		else if (dev->mode == IMM_EPP_16 && !(((long) buffer | len) & 0x01))
377 			outsw(ppb + 4, buffer, len >> 1);
378 		else
379 			outsb(ppb + 4, buffer, len);
380 		w_ctr(ppb, 0xc);
381 		r = !(r_str(ppb) & 0x01);
382 		w_ctr(ppb, 0xc);
383 		ecp_sync(dev);
384 		break;
385 
386 	case IMM_NIBBLE:
387 	case IMM_PS2:
388 		/* 8 bit output, with a loop */
389 		r = imm_byte_out(ppb, buffer, len);
390 		break;
391 
392 	default:
393 		printk("IMM: bug in imm_out()\n");
394 		r = 0;
395 	}
396 	return r;
397 }
398 
399 static int imm_in(imm_struct *dev, char *buffer, int len)
400 {
401 	unsigned short ppb = dev->base;
402 	int r = imm_wait(dev);
403 
404 	/*
405 	 * Make sure that:
406 	 * a) the SCSI bus is BUSY (device still listening)
407 	 * b) the device is sending data
408 	 */
409 	if ((r & 0x18) != 0x18) {
410 		imm_fail(dev, DID_ERROR);
411 		return 0;
412 	}
413 	switch (dev->mode) {
414 	case IMM_NIBBLE:
415 		/* 4 bit input, with a loop */
416 		r = imm_nibble_in(ppb, buffer, len);
417 		w_ctr(ppb, 0xc);
418 		break;
419 
420 	case IMM_PS2:
421 		/* 8 bit input, with a loop */
422 		r = imm_byte_in(ppb, buffer, len);
423 		w_ctr(ppb, 0xc);
424 		break;
425 
426 	case IMM_EPP_32:
427 	case IMM_EPP_16:
428 	case IMM_EPP_8:
429 		epp_reset(ppb);
430 		w_ctr(ppb, 0x24);
431 		if (dev->mode == IMM_EPP_32 && !(((long) buffer | len) & 0x03))
432 			insw(ppb + 4, buffer, len >> 2);
433 		else if (dev->mode == IMM_EPP_16 && !(((long) buffer | len) & 0x01))
434 			insl(ppb + 4, buffer, len >> 1);
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 	bool autodetect = dev->mode == IMM_AUTODETECT;
592 
593 	if (autodetect) {
594 		int modes = dev->dev->port->modes;
595 
596 		/* Mode detection works up the chain of speed
597 		 * This avoids a nasty if-then-else-if-... tree
598 		 */
599 		dev->mode = IMM_NIBBLE;
600 
601 		if (modes & PARPORT_MODE_TRISTATE)
602 			dev->mode = IMM_PS2;
603 	}
604 
605 	if (imm_connect(dev, 0) != 1)
606 		return -EIO;
607 	imm_reset_pulse(dev->base);
608 	mdelay(1);	/* Delay to allow devices to settle */
609 	imm_disconnect(dev);
610 	mdelay(1);	/* Another delay to allow devices to settle */
611 
612 	return device_check(dev, autodetect);
613 }
614 
615 static inline int imm_send_command(struct scsi_cmnd *cmd)
616 {
617 	imm_struct *dev = imm_dev(cmd->device->host);
618 	int k;
619 
620 	/* NOTE: IMM uses byte pairs */
621 	for (k = 0; k < cmd->cmd_len; k += 2)
622 		if (!imm_out(dev, &cmd->cmnd[k], 2))
623 			return 0;
624 	return 1;
625 }
626 
627 /*
628  * The bulk flag enables some optimisations in the data transfer loops,
629  * it should be true for any command that transfers data in integral
630  * numbers of sectors.
631  *
632  * The driver appears to remain stable if we speed up the parallel port
633  * i/o in this function, but not elsewhere.
634  */
635 static int imm_completion(struct scsi_cmnd *const cmd)
636 {
637 	/* Return codes:
638 	 * -1     Error
639 	 *  0     Told to schedule
640 	 *  1     Finished data transfer
641 	 */
642 	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
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 || scsi_pointer->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 && scsi_pointer->this_residual >=
685 				IMM_BURST_SIZE ? IMM_BURST_SIZE : 2;
686 			status = imm_out(dev, scsi_pointer->ptr, fast);
687 		} else {
688 			fast = bulk && scsi_pointer->this_residual >=
689 				IMM_BURST_SIZE ? IMM_BURST_SIZE : 1;
690 			status = imm_in(dev, scsi_pointer->ptr, fast);
691 		}
692 
693 		scsi_pointer->ptr += fast;
694 		scsi_pointer->this_residual -= fast;
695 
696 		if (!status) {
697 			imm_fail(dev, DID_BUS_BUSY);
698 			return -1;	/* ERROR_RETURN */
699 		}
700 		if (scsi_pointer->buffer && !scsi_pointer->this_residual) {
701 			/* if scatter/gather, advance to the next segment */
702 			if (scsi_pointer->buffers_residual--) {
703 				scsi_pointer->buffer =
704 					sg_next(scsi_pointer->buffer);
705 				scsi_pointer->this_residual =
706 				    scsi_pointer->buffer->length;
707 				scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
708 
709 				/*
710 				 * Make sure that we transfer even number of bytes
711 				 * otherwise it makes imm_byte_out() messy.
712 				 */
713 				if (scsi_pointer->this_residual & 0x01)
714 					scsi_pointer->this_residual++;
715 			}
716 		}
717 		/* Now check to see if the drive is ready to comunicate */
718 		w_ctr(ppb, 0x0c);
719 		r = (r_str(ppb) & 0xb8);
720 
721 		/* If not, drop back down to the scheduler and wait a timer tick */
722 		if (!(r & 0x80))
723 			return 0;
724 	}
725 	return 1;		/* FINISH_RETURN */
726 }
727 
728 /*
729  * Since the IMM itself doesn't generate interrupts, we use
730  * the scheduler's task queue to generate a stream of call-backs and
731  * complete the request when the drive is ready.
732  */
733 static void imm_interrupt(struct work_struct *work)
734 {
735 	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
736 	struct scsi_cmnd *cmd = dev->cur_cmd;
737 	struct Scsi_Host *host = cmd->device->host;
738 	unsigned long flags;
739 
740 	if (imm_engine(dev, cmd)) {
741 		schedule_delayed_work(&dev->imm_tq, 1);
742 		return;
743 	}
744 	/* Command must of completed hence it is safe to let go... */
745 #if IMM_DEBUG > 0
746 	switch ((cmd->result >> 16) & 0xff) {
747 	case DID_OK:
748 		break;
749 	case DID_NO_CONNECT:
750 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
751 		break;
752 	case DID_BUS_BUSY:
753 		printk("imm: BUS BUSY - EPP timeout detected\n");
754 		break;
755 	case DID_TIME_OUT:
756 		printk("imm: unknown timeout\n");
757 		break;
758 	case DID_ABORT:
759 		printk("imm: told to abort\n");
760 		break;
761 	case DID_PARITY:
762 		printk("imm: parity error (???)\n");
763 		break;
764 	case DID_ERROR:
765 		printk("imm: internal driver error\n");
766 		break;
767 	case DID_RESET:
768 		printk("imm: told to reset device\n");
769 		break;
770 	case DID_BAD_INTR:
771 		printk("imm: bad interrupt (???)\n");
772 		break;
773 	default:
774 		printk("imm: bad return code (%02x)\n",
775 		       (cmd->result >> 16) & 0xff);
776 	}
777 #endif
778 
779 	if (imm_scsi_pointer(cmd)->phase > 1)
780 		imm_disconnect(dev);
781 
782 	imm_pb_dismiss(dev);
783 
784 	spin_lock_irqsave(host->host_lock, flags);
785 	dev->cur_cmd = NULL;
786 	scsi_done(cmd);
787 	spin_unlock_irqrestore(host->host_lock, flags);
788 	return;
789 }
790 
791 static int imm_engine(imm_struct *dev, struct scsi_cmnd *const cmd)
792 {
793 	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
794 	unsigned short ppb = dev->base;
795 	unsigned char l = 0, h = 0;
796 	int retv, x;
797 
798 	/* First check for any errors that may have occurred
799 	 * Here we check for internal errors
800 	 */
801 	if (dev->failed)
802 		return 0;
803 
804 	switch (scsi_pointer->phase) {
805 	case 0:		/* Phase 0 - Waiting for parport */
806 		if (time_after(jiffies, dev->jstart + HZ)) {
807 			/*
808 			 * We waited more than a second
809 			 * for parport to call us
810 			 */
811 			imm_fail(dev, DID_BUS_BUSY);
812 			return 0;
813 		}
814 		return 1;	/* wait until imm_wakeup claims parport */
815 
816 	case 1:		/* Phase 1 - Connected */
817 		imm_connect(dev, CONNECT_EPP_MAYBE);
818 		scsi_pointer->phase++;
819 		fallthrough;
820 
821 	case 2:		/* Phase 2 - We are now talking to the scsi bus */
822 		if (!imm_select(dev, scmd_id(cmd))) {
823 			imm_fail(dev, DID_NO_CONNECT);
824 			return 0;
825 		}
826 		scsi_pointer->phase++;
827 		fallthrough;
828 
829 	case 3:		/* Phase 3 - Ready to accept a command */
830 		w_ctr(ppb, 0x0c);
831 		if (!(r_str(ppb) & 0x80))
832 			return 1;
833 
834 		if (!imm_send_command(cmd))
835 			return 0;
836 		scsi_pointer->phase++;
837 		fallthrough;
838 
839 	case 4:		/* Phase 4 - Setup scatter/gather buffers */
840 		if (scsi_bufflen(cmd)) {
841 			scsi_pointer->buffer = scsi_sglist(cmd);
842 			scsi_pointer->this_residual = scsi_pointer->buffer->length;
843 			scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
844 		} else {
845 			scsi_pointer->buffer = NULL;
846 			scsi_pointer->this_residual = 0;
847 			scsi_pointer->ptr = NULL;
848 		}
849 		scsi_pointer->buffers_residual = scsi_sg_count(cmd) - 1;
850 		scsi_pointer->phase++;
851 		if (scsi_pointer->this_residual & 0x01)
852 			scsi_pointer->this_residual++;
853 		fallthrough;
854 
855 	case 5:		/* Phase 5 - Pre-Data transfer stage */
856 		/* Spin lock for BUSY */
857 		w_ctr(ppb, 0x0c);
858 		if (!(r_str(ppb) & 0x80))
859 			return 1;
860 
861 		/* Require negotiation for read requests */
862 		x = (r_str(ppb) & 0xb8);
863 		dev->rd = (x & 0x10) ? 1 : 0;
864 		dev->dp = (x & 0x20) ? 0 : 1;
865 
866 		if ((dev->dp) && (dev->rd))
867 			if (imm_negotiate(dev))
868 				return 0;
869 		scsi_pointer->phase++;
870 		fallthrough;
871 
872 	case 6:		/* Phase 6 - Data transfer stage */
873 		/* Spin lock for BUSY */
874 		w_ctr(ppb, 0x0c);
875 		if (!(r_str(ppb) & 0x80))
876 			return 1;
877 
878 		if (dev->dp) {
879 			retv = imm_completion(cmd);
880 			if (retv == -1)
881 				return 0;
882 			if (retv == 0)
883 				return 1;
884 		}
885 		scsi_pointer->phase++;
886 		fallthrough;
887 
888 	case 7:		/* Phase 7 - Post data transfer stage */
889 		if ((dev->dp) && (dev->rd)) {
890 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
891 				w_ctr(ppb, 0x4);
892 				w_ctr(ppb, 0xc);
893 				w_ctr(ppb, 0xe);
894 				w_ctr(ppb, 0x4);
895 			}
896 		}
897 		scsi_pointer->phase++;
898 		fallthrough;
899 
900 	case 8:		/* Phase 8 - Read status/message */
901 		/* Check for data overrun */
902 		if (imm_wait(dev) != (unsigned char) 0xb8) {
903 			imm_fail(dev, DID_ERROR);
904 			return 0;
905 		}
906 		if (imm_negotiate(dev))
907 			return 0;
908 		if (imm_in(dev, &l, 1)) {	/* read status byte */
909 			/* Check for optional message byte */
910 			if (imm_wait(dev) == (unsigned char) 0xb8)
911 				imm_in(dev, &h, 1);
912 			cmd->result = (DID_OK << 16) | (l & STATUS_MASK);
913 		}
914 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
915 			w_ctr(ppb, 0x4);
916 			w_ctr(ppb, 0xc);
917 			w_ctr(ppb, 0xe);
918 			w_ctr(ppb, 0x4);
919 		}
920 		return 0;	/* Finished */
921 
922 	default:
923 		printk("imm: Invalid scsi phase\n");
924 	}
925 	return 0;
926 }
927 
928 static int imm_queuecommand_lck(struct scsi_cmnd *cmd)
929 {
930 	imm_struct *dev = imm_dev(cmd->device->host);
931 
932 	if (dev->cur_cmd) {
933 		printk("IMM: bug in imm_queuecommand\n");
934 		return 0;
935 	}
936 	dev->failed = 0;
937 	dev->jstart = jiffies;
938 	dev->cur_cmd = cmd;
939 	cmd->result = DID_ERROR << 16;	/* default return code */
940 	imm_scsi_pointer(cmd)->phase = 0;	/* bus free */
941 
942 	schedule_delayed_work(&dev->imm_tq, 0);
943 
944 	imm_pb_claim(dev);
945 
946 	return 0;
947 }
948 
949 static DEF_SCSI_QCMD(imm_queuecommand)
950 
951 /*
952  * Apparently the disk->capacity attribute is off by 1 sector
953  * for all disk drives.  We add the one here, but it should really
954  * be done in sd.c.  Even if it gets fixed there, this will still
955  * work.
956  */
957 static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
958 			 sector_t capacity, int ip[])
959 {
960 	ip[0] = 0x40;
961 	ip[1] = 0x20;
962 	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
963 	if (ip[2] > 1024) {
964 		ip[0] = 0xff;
965 		ip[1] = 0x3f;
966 		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
967 	}
968 	return 0;
969 }
970 
971 static int imm_abort(struct scsi_cmnd *cmd)
972 {
973 	imm_struct *dev = imm_dev(cmd->device->host);
974 	/*
975 	 * There is no method for aborting commands since Iomega
976 	 * have tied the SCSI_MESSAGE line high in the interface
977 	 */
978 
979 	switch (imm_scsi_pointer(cmd)->phase) {
980 	case 0:		/* Do not have access to parport */
981 	case 1:		/* Have not connected to interface */
982 		dev->cur_cmd = NULL;	/* Forget the problem */
983 		return SUCCESS;
984 	default:		/* SCSI command sent, can not abort */
985 		return FAILED;
986 	}
987 }
988 
989 static void imm_reset_pulse(unsigned int base)
990 {
991 	w_ctr(base, 0x04);
992 	w_dtr(base, 0x40);
993 	udelay(1);
994 	w_ctr(base, 0x0c);
995 	w_ctr(base, 0x0d);
996 	udelay(50);
997 	w_ctr(base, 0x0c);
998 	w_ctr(base, 0x04);
999 }
1000 
1001 static int imm_reset(struct scsi_cmnd *cmd)
1002 {
1003 	imm_struct *dev = imm_dev(cmd->device->host);
1004 
1005 	if (imm_scsi_pointer(cmd)->phase)
1006 		imm_disconnect(dev);
1007 	dev->cur_cmd = NULL;	/* Forget the problem */
1008 
1009 	imm_connect(dev, CONNECT_NORMAL);
1010 	imm_reset_pulse(dev->base);
1011 	mdelay(1);		/* device settle delay */
1012 	imm_disconnect(dev);
1013 	mdelay(1);		/* device settle delay */
1014 	return SUCCESS;
1015 }
1016 
1017 static int device_check(imm_struct *dev, bool autodetect)
1018 {
1019 	/* This routine looks for a device and then attempts to use EPP
1020 	   to send a command. If all goes as planned then EPP is available. */
1021 
1022 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1023 	int loop, old_mode, status, k, ppb = dev->base;
1024 	unsigned char l;
1025 
1026 	old_mode = dev->mode;
1027 	for (loop = 0; loop < 8; loop++) {
1028 		/* Attempt to use EPP for Test Unit Ready */
1029 		if (autodetect && (ppb & 0x0007) == 0x0000)
1030 			dev->mode = IMM_EPP_8;
1031 
1032 	      second_pass:
1033 		imm_connect(dev, CONNECT_EPP_MAYBE);
1034 		/* Select SCSI device */
1035 		if (!imm_select(dev, loop)) {
1036 			imm_disconnect(dev);
1037 			continue;
1038 		}
1039 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1040 		       loop, IMM_MODE_STRING[dev->mode]);
1041 
1042 		/* Send SCSI command */
1043 		status = 1;
1044 		w_ctr(ppb, 0x0c);
1045 		for (l = 0; (l < 3) && (status); l++)
1046 			status = imm_out(dev, &cmd[l << 1], 2);
1047 
1048 		if (!status) {
1049 			imm_disconnect(dev);
1050 			imm_connect(dev, CONNECT_EPP_MAYBE);
1051 			imm_reset_pulse(dev->base);
1052 			udelay(1000);
1053 			imm_disconnect(dev);
1054 			udelay(1000);
1055 			if (dev->mode != old_mode) {
1056 				dev->mode = old_mode;
1057 				goto second_pass;
1058 			}
1059 			printk("imm: Unable to establish communication\n");
1060 			return -EIO;
1061 		}
1062 		w_ctr(ppb, 0x0c);
1063 
1064 		k = 1000000;	/* 1 Second */
1065 		do {
1066 			l = r_str(ppb);
1067 			k--;
1068 			udelay(1);
1069 		} while (!(l & 0x80) && (k));
1070 
1071 		l &= 0xb8;
1072 
1073 		if (l != 0xb8) {
1074 			imm_disconnect(dev);
1075 			imm_connect(dev, CONNECT_EPP_MAYBE);
1076 			imm_reset_pulse(dev->base);
1077 			udelay(1000);
1078 			imm_disconnect(dev);
1079 			udelay(1000);
1080 			if (dev->mode != old_mode) {
1081 				dev->mode = old_mode;
1082 				goto second_pass;
1083 			}
1084 			printk
1085 			    ("imm: Unable to establish communication\n");
1086 			return -EIO;
1087 		}
1088 		imm_disconnect(dev);
1089 		printk
1090 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1091 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1092 		imm_connect(dev, CONNECT_EPP_MAYBE);
1093 		imm_reset_pulse(dev->base);
1094 		udelay(1000);
1095 		imm_disconnect(dev);
1096 		udelay(1000);
1097 		return 0;
1098 	}
1099 	printk("imm: No devices found\n");
1100 	return -ENODEV;
1101 }
1102 
1103 static const struct scsi_host_template imm_template = {
1104 	.module			= THIS_MODULE,
1105 	.proc_name		= "imm",
1106 	.show_info		= imm_show_info,
1107 	.write_info		= imm_write_info,
1108 	.name			= "Iomega VPI2 (imm) interface",
1109 	.queuecommand		= imm_queuecommand,
1110 	.eh_abort_handler	= imm_abort,
1111 	.eh_host_reset_handler	= imm_reset,
1112 	.bios_param		= imm_biosparam,
1113 	.this_id		= 7,
1114 	.sg_tablesize		= SG_ALL,
1115 	.can_queue		= 1,
1116 	.cmd_size		= sizeof(struct scsi_pointer),
1117 };
1118 
1119 /***************************************************************************
1120  *                   Parallel port probing routines                        *
1121  ***************************************************************************/
1122 
1123 static LIST_HEAD(imm_hosts);
1124 
1125 /*
1126  * Finds the first available device number that can be alloted to the
1127  * new imm device and returns the address of the previous node so that
1128  * we can add to the tail and have a list in the ascending order.
1129  */
1130 
1131 static inline imm_struct *find_parent(void)
1132 {
1133 	imm_struct *dev, *par = NULL;
1134 	unsigned int cnt = 0;
1135 
1136 	if (list_empty(&imm_hosts))
1137 		return NULL;
1138 
1139 	list_for_each_entry(dev, &imm_hosts, list) {
1140 		if (dev->dev_no != cnt)
1141 			return par;
1142 		cnt++;
1143 		par = dev;
1144 	}
1145 
1146 	return par;
1147 }
1148 
1149 static int __imm_attach(struct parport *pb)
1150 {
1151 	struct Scsi_Host *host;
1152 	imm_struct *dev, *temp;
1153 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1154 	DEFINE_WAIT(wait);
1155 	int ports;
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 = mode < IMM_UNKNOWN ? 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 	dev->base = dev->dev->port->base;
1203 	dev->base_hi = dev->dev->port->base_hi;
1204 	w_ctr(dev->base, 0x0c);
1205 
1206 	/* Done configuration */
1207 
1208 	err = imm_init(dev);
1209 
1210 	imm_pb_release(dev);
1211 
1212 	if (err)
1213 		goto out1;
1214 
1215 	/* now the glue ... */
1216 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1217 		ports = 3;
1218 	else
1219 		ports = 8;
1220 
1221 	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1222 
1223 	err = -ENOMEM;
1224 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1225 	if (!host)
1226 		goto out1;
1227 	host->no_highmem = true;
1228 	host->io_port = pb->base;
1229 	host->n_io_port = ports;
1230 	host->dma_channel = -1;
1231 	host->unique_id = pb->number;
1232 	*(imm_struct **)&host->hostdata = dev;
1233 	dev->host = host;
1234 	if (!temp)
1235 		list_add_tail(&dev->list, &imm_hosts);
1236 	else
1237 		list_add_tail(&dev->list, &temp->list);
1238 	err = scsi_add_host(host, NULL);
1239 	if (err)
1240 		goto out2;
1241 	scsi_scan_host(host);
1242 	return 0;
1243 
1244 out2:
1245 	list_del_init(&dev->list);
1246 	scsi_host_put(host);
1247 out1:
1248 	parport_unregister_device(dev->dev);
1249 out:
1250 	kfree(dev);
1251 	return err;
1252 }
1253 
1254 static void imm_attach(struct parport *pb)
1255 {
1256 	__imm_attach(pb);
1257 }
1258 
1259 static void imm_detach(struct parport *pb)
1260 {
1261 	imm_struct *dev;
1262 	list_for_each_entry(dev, &imm_hosts, list) {
1263 		if (dev->dev->port == pb) {
1264 			list_del_init(&dev->list);
1265 			scsi_remove_host(dev->host);
1266 			scsi_host_put(dev->host);
1267 			parport_unregister_device(dev->dev);
1268 			kfree(dev);
1269 			break;
1270 		}
1271 	}
1272 }
1273 
1274 static struct parport_driver imm_driver = {
1275 	.name		= "imm",
1276 	.match_port	= imm_attach,
1277 	.detach		= imm_detach,
1278 };
1279 module_parport_driver(imm_driver);
1280 
1281 MODULE_DESCRIPTION("IOMEGA MatchMaker parallel port SCSI host adapter driver");
1282 MODULE_LICENSE("GPL");
1283