xref: /openbmc/linux/drivers/scsi/imm.c (revision e40573a4)
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);
55 
56 #include "imm.h"
57 
58 static inline imm_struct *imm_dev(struct Scsi_Host *host)
59 {
60 	return *(imm_struct **)&host->hostdata;
61 }
62 
63 static DEFINE_SPINLOCK(arbitration_lock);
64 
65 static void got_it(imm_struct *dev)
66 {
67 	dev->base = dev->dev->port->base;
68 	if (dev->cur_cmd)
69 		imm_scsi_pointer(dev->cur_cmd)->phase = 1;
70 	else
71 		wake_up(dev->waiting);
72 }
73 
74 static void imm_wakeup(void *ref)
75 {
76 	imm_struct *dev = (imm_struct *) ref;
77 	unsigned long flags;
78 
79 	spin_lock_irqsave(&arbitration_lock, flags);
80 	if (dev->wanted) {
81 		if (parport_claim(dev->dev) == 0) {
82 			got_it(dev);
83 			dev->wanted = 0;
84 		}
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 int imm_write_info(struct Scsi_Host *host, char *buffer, int length)
128 {
129 	imm_struct *dev = imm_dev(host);
130 
131 	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
132 		dev->mode = simple_strtoul(buffer + 5, NULL, 0);
133 		return length;
134 	}
135 	printk("imm /proc: invalid variable\n");
136 	return -EINVAL;
137 }
138 
139 static int imm_show_info(struct seq_file *m, struct Scsi_Host *host)
140 {
141 	imm_struct *dev = imm_dev(host);
142 
143 	seq_printf(m, "Version : %s\n", IMM_VERSION);
144 	seq_printf(m, "Parport : %s\n", dev->dev->port->name);
145 	seq_printf(m, "Mode    : %s\n", IMM_MODE_STRING[dev->mode]);
146 	return 0;
147 }
148 
149 #if IMM_DEBUG > 0
150 #define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
151 	   y, __func__, __LINE__); imm_fail_func(x,y);
152 static inline void
153 imm_fail_func(imm_struct *dev, int error_code)
154 #else
155 static inline void
156 imm_fail(imm_struct *dev, int error_code)
157 #endif
158 {
159 	/* If we fail a device then we trash status / message bytes */
160 	if (dev->cur_cmd) {
161 		dev->cur_cmd->result = error_code << 16;
162 		dev->failed = 1;
163 	}
164 }
165 
166 /*
167  * Wait for the high bit to be set.
168  *
169  * In principle, this could be tied to an interrupt, but the adapter
170  * doesn't appear to be designed to support interrupts.  We spin on
171  * the 0x80 ready bit.
172  */
173 static unsigned char imm_wait(imm_struct *dev)
174 {
175 	int k;
176 	unsigned short ppb = dev->base;
177 	unsigned char r;
178 
179 	w_ctr(ppb, 0x0c);
180 
181 	k = IMM_SPIN_TMO;
182 	do {
183 		r = r_str(ppb);
184 		k--;
185 		udelay(1);
186 	}
187 	while (!(r & 0x80) && (k));
188 
189 	/*
190 	 * STR register (LPT base+1) to SCSI mapping:
191 	 *
192 	 * STR      imm     imm
193 	 * ===================================
194 	 * 0x80     S_REQ   S_REQ
195 	 * 0x40     !S_BSY  (????)
196 	 * 0x20     !S_CD   !S_CD
197 	 * 0x10     !S_IO   !S_IO
198 	 * 0x08     (????)  !S_BSY
199 	 *
200 	 * imm      imm     meaning
201 	 * ==================================
202 	 * 0xf0     0xb8    Bit mask
203 	 * 0xc0     0x88    ZIP wants more data
204 	 * 0xd0     0x98    ZIP wants to send more data
205 	 * 0xe0     0xa8    ZIP is expecting SCSI command data
206 	 * 0xf0     0xb8    end of transfer, ZIP is sending status
207 	 */
208 	w_ctr(ppb, 0x04);
209 	if (k)
210 		return (r & 0xb8);
211 
212 	/* Counter expired - Time out occurred */
213 	imm_fail(dev, DID_TIME_OUT);
214 	printk("imm timeout in imm_wait\n");
215 	return 0;		/* command timed out */
216 }
217 
218 static int imm_negotiate(imm_struct * tmp)
219 {
220 	/*
221 	 * The following is supposedly the IEEE 1284-1994 negotiate
222 	 * sequence. I have yet to obtain a copy of the above standard
223 	 * so this is a bit of a guess...
224 	 *
225 	 * A fair chunk of this is based on the Linux parport implementation
226 	 * of IEEE 1284.
227 	 *
228 	 * Return 0 if data available
229 	 *        1 if no data available
230 	 */
231 
232 	unsigned short base = tmp->base;
233 	unsigned char a, mode;
234 
235 	switch (tmp->mode) {
236 	case IMM_NIBBLE:
237 		mode = 0x00;
238 		break;
239 	case IMM_PS2:
240 		mode = 0x01;
241 		break;
242 	default:
243 		return 0;
244 	}
245 
246 	w_ctr(base, 0x04);
247 	udelay(5);
248 	w_dtr(base, mode);
249 	udelay(100);
250 	w_ctr(base, 0x06);
251 	udelay(5);
252 	a = (r_str(base) & 0x20) ? 0 : 1;
253 	udelay(5);
254 	w_ctr(base, 0x07);
255 	udelay(5);
256 	w_ctr(base, 0x06);
257 
258 	if (a) {
259 		printk
260 		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
261 		imm_fail(tmp, DID_ERROR);
262 	}
263 	return a;
264 }
265 
266 /*
267  * Clear EPP timeout bit.
268  */
269 static inline void epp_reset(unsigned short ppb)
270 {
271 	int i;
272 
273 	i = r_str(ppb);
274 	w_str(ppb, i);
275 	w_str(ppb, i & 0xfe);
276 }
277 
278 /*
279  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
280  */
281 static inline void ecp_sync(imm_struct *dev)
282 {
283 	int i, ppb_hi = dev->base_hi;
284 
285 	if (ppb_hi == 0)
286 		return;
287 
288 	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
289 		for (i = 0; i < 100; i++) {
290 			if (r_ecr(ppb_hi) & 0x01)
291 				return;
292 			udelay(5);
293 		}
294 		printk("imm: ECP sync failed as data still present in FIFO.\n");
295 	}
296 }
297 
298 static int imm_byte_out(unsigned short base, const char *buffer, int len)
299 {
300 	int i;
301 
302 	w_ctr(base, 0x4);	/* apparently a sane mode */
303 	for (i = len >> 1; i; i--) {
304 		w_dtr(base, *buffer++);
305 		w_ctr(base, 0x5);	/* Drop STROBE low */
306 		w_dtr(base, *buffer++);
307 		w_ctr(base, 0x0);	/* STROBE high + INIT low */
308 	}
309 	w_ctr(base, 0x4);	/* apparently a sane mode */
310 	return 1;		/* All went well - we hope! */
311 }
312 
313 static int imm_nibble_in(unsigned short base, char *buffer, int len)
314 {
315 	unsigned char l;
316 	int i;
317 
318 	/*
319 	 * The following is based on documented timing signals
320 	 */
321 	w_ctr(base, 0x4);
322 	for (i = len; i; i--) {
323 		w_ctr(base, 0x6);
324 		l = (r_str(base) & 0xf0) >> 4;
325 		w_ctr(base, 0x5);
326 		*buffer++ = (r_str(base) & 0xf0) | l;
327 		w_ctr(base, 0x4);
328 	}
329 	return 1;		/* All went well - we hope! */
330 }
331 
332 static int imm_byte_in(unsigned short base, char *buffer, int len)
333 {
334 	int i;
335 
336 	/*
337 	 * The following is based on documented timing signals
338 	 */
339 	w_ctr(base, 0x4);
340 	for (i = len; i; i--) {
341 		w_ctr(base, 0x26);
342 		*buffer++ = r_dtr(base);
343 		w_ctr(base, 0x25);
344 	}
345 	return 1;		/* All went well - we hope! */
346 }
347 
348 static int imm_out(imm_struct *dev, char *buffer, int len)
349 {
350 	unsigned short ppb = dev->base;
351 	int r = imm_wait(dev);
352 
353 	/*
354 	 * Make sure that:
355 	 * a) the SCSI bus is BUSY (device still listening)
356 	 * b) the device is listening
357 	 */
358 	if ((r & 0x18) != 0x08) {
359 		imm_fail(dev, DID_ERROR);
360 		printk("IMM: returned SCSI status %2x\n", r);
361 		return 0;
362 	}
363 	switch (dev->mode) {
364 	case IMM_EPP_32:
365 	case IMM_EPP_16:
366 	case IMM_EPP_8:
367 		epp_reset(ppb);
368 		w_ctr(ppb, 0x4);
369 #ifdef CONFIG_SCSI_IZIP_EPP16
370 		if (!(((long) buffer | len) & 0x01))
371 			outsw(ppb + 4, buffer, len >> 1);
372 #else
373 		if (!(((long) buffer | len) & 0x03))
374 			outsl(ppb + 4, buffer, len >> 2);
375 #endif
376 		else
377 			outsb(ppb + 4, buffer, len);
378 		w_ctr(ppb, 0xc);
379 		r = !(r_str(ppb) & 0x01);
380 		w_ctr(ppb, 0xc);
381 		ecp_sync(dev);
382 		break;
383 
384 	case IMM_NIBBLE:
385 	case IMM_PS2:
386 		/* 8 bit output, with a loop */
387 		r = imm_byte_out(ppb, buffer, len);
388 		break;
389 
390 	default:
391 		printk("IMM: bug in imm_out()\n");
392 		r = 0;
393 	}
394 	return r;
395 }
396 
397 static int imm_in(imm_struct *dev, char *buffer, int len)
398 {
399 	unsigned short ppb = dev->base;
400 	int r = imm_wait(dev);
401 
402 	/*
403 	 * Make sure that:
404 	 * a) the SCSI bus is BUSY (device still listening)
405 	 * b) the device is sending data
406 	 */
407 	if ((r & 0x18) != 0x18) {
408 		imm_fail(dev, DID_ERROR);
409 		return 0;
410 	}
411 	switch (dev->mode) {
412 	case IMM_NIBBLE:
413 		/* 4 bit input, with a loop */
414 		r = imm_nibble_in(ppb, buffer, len);
415 		w_ctr(ppb, 0xc);
416 		break;
417 
418 	case IMM_PS2:
419 		/* 8 bit input, with a loop */
420 		r = imm_byte_in(ppb, buffer, len);
421 		w_ctr(ppb, 0xc);
422 		break;
423 
424 	case IMM_EPP_32:
425 	case IMM_EPP_16:
426 	case IMM_EPP_8:
427 		epp_reset(ppb);
428 		w_ctr(ppb, 0x24);
429 #ifdef CONFIG_SCSI_IZIP_EPP16
430 		if (!(((long) buffer | len) & 0x01))
431 			insw(ppb + 4, buffer, len >> 1);
432 #else
433 		if (!(((long) buffer | len) & 0x03))
434 			insl(ppb + 4, buffer, len >> 2);
435 #endif
436 		else
437 			insb(ppb + 4, buffer, len);
438 		w_ctr(ppb, 0x2c);
439 		r = !(r_str(ppb) & 0x01);
440 		w_ctr(ppb, 0x2c);
441 		ecp_sync(dev);
442 		break;
443 
444 	default:
445 		printk("IMM: bug in imm_ins()\n");
446 		r = 0;
447 		break;
448 	}
449 	return r;
450 }
451 
452 static int imm_cpp(unsigned short ppb, unsigned char b)
453 {
454 	/*
455 	 * Comments on udelay values refer to the
456 	 * Command Packet Protocol (CPP) timing diagram.
457 	 */
458 
459 	unsigned char s1, s2, s3;
460 	w_ctr(ppb, 0x0c);
461 	udelay(2);		/* 1 usec - infinite */
462 	w_dtr(ppb, 0xaa);
463 	udelay(10);		/* 7 usec - infinite */
464 	w_dtr(ppb, 0x55);
465 	udelay(10);		/* 7 usec - infinite */
466 	w_dtr(ppb, 0x00);
467 	udelay(10);		/* 7 usec - infinite */
468 	w_dtr(ppb, 0xff);
469 	udelay(10);		/* 7 usec - infinite */
470 	s1 = r_str(ppb) & 0xb8;
471 	w_dtr(ppb, 0x87);
472 	udelay(10);		/* 7 usec - infinite */
473 	s2 = r_str(ppb) & 0xb8;
474 	w_dtr(ppb, 0x78);
475 	udelay(10);		/* 7 usec - infinite */
476 	s3 = r_str(ppb) & 0x38;
477 	/*
478 	 * Values for b are:
479 	 * 0000 00aa    Assign address aa to current device
480 	 * 0010 00aa    Select device aa in EPP Winbond mode
481 	 * 0010 10aa    Select device aa in EPP mode
482 	 * 0011 xxxx    Deselect all devices
483 	 * 0110 00aa    Test device aa
484 	 * 1101 00aa    Select device aa in ECP mode
485 	 * 1110 00aa    Select device aa in Compatible mode
486 	 */
487 	w_dtr(ppb, b);
488 	udelay(2);		/* 1 usec - infinite */
489 	w_ctr(ppb, 0x0c);
490 	udelay(10);		/* 7 usec - infinite */
491 	w_ctr(ppb, 0x0d);
492 	udelay(2);		/* 1 usec - infinite */
493 	w_ctr(ppb, 0x0c);
494 	udelay(10);		/* 7 usec - infinite */
495 	w_dtr(ppb, 0xff);
496 	udelay(10);		/* 7 usec - infinite */
497 
498 	/*
499 	 * The following table is electrical pin values.
500 	 * (BSY is inverted at the CTR register)
501 	 *
502 	 *       BSY  ACK  POut SEL  Fault
503 	 * S1    0    X    1    1    1
504 	 * S2    1    X    0    1    1
505 	 * S3    L    X    1    1    S
506 	 *
507 	 * L => Last device in chain
508 	 * S => Selected
509 	 *
510 	 * Observered values for S1,S2,S3 are:
511 	 * Disconnect => f8/58/78
512 	 * Connect    => f8/58/70
513 	 */
514 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
515 		return 1;	/* Connected */
516 	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
517 		return 0;	/* Disconnected */
518 
519 	return -1;		/* No device present */
520 }
521 
522 static inline int imm_connect(imm_struct *dev, int flag)
523 {
524 	unsigned short ppb = dev->base;
525 
526 	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
527 	imm_cpp(ppb, 0x30);	/* Disconnect all devices */
528 
529 	if ((dev->mode == IMM_EPP_8) ||
530 	    (dev->mode == IMM_EPP_16) ||
531 	    (dev->mode == IMM_EPP_32))
532 		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
533 	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
534 }
535 
536 static void imm_disconnect(imm_struct *dev)
537 {
538 	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
539 }
540 
541 static int imm_select(imm_struct *dev, int target)
542 {
543 	int k;
544 	unsigned short ppb = dev->base;
545 
546 	/*
547 	 * Firstly we want to make sure there is nothing
548 	 * holding onto the SCSI bus.
549 	 */
550 	w_ctr(ppb, 0xc);
551 
552 	k = IMM_SELECT_TMO;
553 	do {
554 		k--;
555 	} while ((r_str(ppb) & 0x08) && (k));
556 
557 	if (!k)
558 		return 0;
559 
560 	/*
561 	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
562 	 */
563 	w_ctr(ppb, 0x4);
564 	w_dtr(ppb, 0x80 | (1 << target));
565 	udelay(1);
566 
567 	/*
568 	 * Deassert SELIN first followed by STROBE
569 	 */
570 	w_ctr(ppb, 0xc);
571 	w_ctr(ppb, 0xd);
572 
573 	/*
574 	 * ACK should drop low while SELIN is deasserted.
575 	 * FAULT should drop low when the SCSI device latches the bus.
576 	 */
577 	k = IMM_SELECT_TMO;
578 	do {
579 		k--;
580 	}
581 	while (!(r_str(ppb) & 0x08) && (k));
582 
583 	/*
584 	 * Place the interface back into a sane state (status mode)
585 	 */
586 	w_ctr(ppb, 0xc);
587 	return (k) ? 1 : 0;
588 }
589 
590 static int imm_init(imm_struct *dev)
591 {
592 	if (imm_connect(dev, 0) != 1)
593 		return -EIO;
594 	imm_reset_pulse(dev->base);
595 	mdelay(1);	/* Delay to allow devices to settle */
596 	imm_disconnect(dev);
597 	mdelay(1);	/* Another delay to allow devices to settle */
598 	return device_check(dev);
599 }
600 
601 static inline int imm_send_command(struct scsi_cmnd *cmd)
602 {
603 	imm_struct *dev = imm_dev(cmd->device->host);
604 	int k;
605 
606 	/* NOTE: IMM uses byte pairs */
607 	for (k = 0; k < cmd->cmd_len; k += 2)
608 		if (!imm_out(dev, &cmd->cmnd[k], 2))
609 			return 0;
610 	return 1;
611 }
612 
613 /*
614  * The bulk flag enables some optimisations in the data transfer loops,
615  * it should be true for any command that transfers data in integral
616  * numbers of sectors.
617  *
618  * The driver appears to remain stable if we speed up the parallel port
619  * i/o in this function, but not elsewhere.
620  */
621 static int imm_completion(struct scsi_cmnd *const cmd)
622 {
623 	/* Return codes:
624 	 * -1     Error
625 	 *  0     Told to schedule
626 	 *  1     Finished data transfer
627 	 */
628 	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
629 	imm_struct *dev = imm_dev(cmd->device->host);
630 	unsigned short ppb = dev->base;
631 	unsigned long start_jiffies = jiffies;
632 
633 	unsigned char r, v;
634 	int fast, bulk, status;
635 
636 	v = cmd->cmnd[0];
637 	bulk = ((v == READ_6) ||
638 		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
639 
640 	/*
641 	 * We only get here if the drive is ready to comunicate,
642 	 * hence no need for a full imm_wait.
643 	 */
644 	w_ctr(ppb, 0x0c);
645 	r = (r_str(ppb) & 0xb8);
646 
647 	/*
648 	 * while (device is not ready to send status byte)
649 	 *     loop;
650 	 */
651 	while (r != (unsigned char) 0xb8) {
652 		/*
653 		 * If we have been running for more than a full timer tick
654 		 * then take a rest.
655 		 */
656 		if (time_after(jiffies, start_jiffies + 1))
657 			return 0;
658 
659 		/*
660 		 * FAIL if:
661 		 * a) Drive status is screwy (!ready && !present)
662 		 * b) Drive is requesting/sending more data than expected
663 		 */
664 		if ((r & 0x88) != 0x88 || scsi_pointer->this_residual <= 0) {
665 			imm_fail(dev, DID_ERROR);
666 			return -1;	/* ERROR_RETURN */
667 		}
668 		/* determine if we should use burst I/O */
669 		if (dev->rd == 0) {
670 			fast = bulk && scsi_pointer->this_residual >=
671 				IMM_BURST_SIZE ? IMM_BURST_SIZE : 2;
672 			status = imm_out(dev, scsi_pointer->ptr, fast);
673 		} else {
674 			fast = bulk && scsi_pointer->this_residual >=
675 				IMM_BURST_SIZE ? IMM_BURST_SIZE : 1;
676 			status = imm_in(dev, scsi_pointer->ptr, fast);
677 		}
678 
679 		scsi_pointer->ptr += fast;
680 		scsi_pointer->this_residual -= fast;
681 
682 		if (!status) {
683 			imm_fail(dev, DID_BUS_BUSY);
684 			return -1;	/* ERROR_RETURN */
685 		}
686 		if (scsi_pointer->buffer && !scsi_pointer->this_residual) {
687 			/* if scatter/gather, advance to the next segment */
688 			if (scsi_pointer->buffers_residual--) {
689 				scsi_pointer->buffer =
690 					sg_next(scsi_pointer->buffer);
691 				scsi_pointer->this_residual =
692 				    scsi_pointer->buffer->length;
693 				scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
694 
695 				/*
696 				 * Make sure that we transfer even number of bytes
697 				 * otherwise it makes imm_byte_out() messy.
698 				 */
699 				if (scsi_pointer->this_residual & 0x01)
700 					scsi_pointer->this_residual++;
701 			}
702 		}
703 		/* Now check to see if the drive is ready to comunicate */
704 		w_ctr(ppb, 0x0c);
705 		r = (r_str(ppb) & 0xb8);
706 
707 		/* If not, drop back down to the scheduler and wait a timer tick */
708 		if (!(r & 0x80))
709 			return 0;
710 	}
711 	return 1;		/* FINISH_RETURN */
712 }
713 
714 /*
715  * Since the IMM itself doesn't generate interrupts, we use
716  * the scheduler's task queue to generate a stream of call-backs and
717  * complete the request when the drive is ready.
718  */
719 static void imm_interrupt(struct work_struct *work)
720 {
721 	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
722 	struct scsi_cmnd *cmd = dev->cur_cmd;
723 	struct Scsi_Host *host = cmd->device->host;
724 	unsigned long flags;
725 
726 	if (imm_engine(dev, cmd)) {
727 		schedule_delayed_work(&dev->imm_tq, 1);
728 		return;
729 	}
730 	/* Command must of completed hence it is safe to let go... */
731 #if IMM_DEBUG > 0
732 	switch ((cmd->result >> 16) & 0xff) {
733 	case DID_OK:
734 		break;
735 	case DID_NO_CONNECT:
736 		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
737 		break;
738 	case DID_BUS_BUSY:
739 		printk("imm: BUS BUSY - EPP timeout detected\n");
740 		break;
741 	case DID_TIME_OUT:
742 		printk("imm: unknown timeout\n");
743 		break;
744 	case DID_ABORT:
745 		printk("imm: told to abort\n");
746 		break;
747 	case DID_PARITY:
748 		printk("imm: parity error (???)\n");
749 		break;
750 	case DID_ERROR:
751 		printk("imm: internal driver error\n");
752 		break;
753 	case DID_RESET:
754 		printk("imm: told to reset device\n");
755 		break;
756 	case DID_BAD_INTR:
757 		printk("imm: bad interrupt (???)\n");
758 		break;
759 	default:
760 		printk("imm: bad return code (%02x)\n",
761 		       (cmd->result >> 16) & 0xff);
762 	}
763 #endif
764 
765 	if (imm_scsi_pointer(cmd)->phase > 1)
766 		imm_disconnect(dev);
767 
768 	imm_pb_dismiss(dev);
769 
770 	spin_lock_irqsave(host->host_lock, flags);
771 	dev->cur_cmd = NULL;
772 	scsi_done(cmd);
773 	spin_unlock_irqrestore(host->host_lock, flags);
774 	return;
775 }
776 
777 static int imm_engine(imm_struct *dev, struct scsi_cmnd *const cmd)
778 {
779 	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
780 	unsigned short ppb = dev->base;
781 	unsigned char l = 0, h = 0;
782 	int retv, x;
783 
784 	/* First check for any errors that may have occurred
785 	 * Here we check for internal errors
786 	 */
787 	if (dev->failed)
788 		return 0;
789 
790 	switch (scsi_pointer->phase) {
791 	case 0:		/* Phase 0 - Waiting for parport */
792 		if (time_after(jiffies, dev->jstart + HZ)) {
793 			/*
794 			 * We waited more than a second
795 			 * for parport to call us
796 			 */
797 			imm_fail(dev, DID_BUS_BUSY);
798 			return 0;
799 		}
800 		return 1;	/* wait until imm_wakeup claims parport */
801 
802 	case 1:		/* Phase 1 - Connected */
803 		imm_connect(dev, CONNECT_EPP_MAYBE);
804 		scsi_pointer->phase++;
805 		fallthrough;
806 
807 	case 2:		/* Phase 2 - We are now talking to the scsi bus */
808 		if (!imm_select(dev, scmd_id(cmd))) {
809 			imm_fail(dev, DID_NO_CONNECT);
810 			return 0;
811 		}
812 		scsi_pointer->phase++;
813 		fallthrough;
814 
815 	case 3:		/* Phase 3 - Ready to accept a command */
816 		w_ctr(ppb, 0x0c);
817 		if (!(r_str(ppb) & 0x80))
818 			return 1;
819 
820 		if (!imm_send_command(cmd))
821 			return 0;
822 		scsi_pointer->phase++;
823 		fallthrough;
824 
825 	case 4:		/* Phase 4 - Setup scatter/gather buffers */
826 		if (scsi_bufflen(cmd)) {
827 			scsi_pointer->buffer = scsi_sglist(cmd);
828 			scsi_pointer->this_residual = scsi_pointer->buffer->length;
829 			scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
830 		} else {
831 			scsi_pointer->buffer = NULL;
832 			scsi_pointer->this_residual = 0;
833 			scsi_pointer->ptr = NULL;
834 		}
835 		scsi_pointer->buffers_residual = scsi_sg_count(cmd) - 1;
836 		scsi_pointer->phase++;
837 		if (scsi_pointer->this_residual & 0x01)
838 			scsi_pointer->this_residual++;
839 		fallthrough;
840 
841 	case 5:		/* Phase 5 - Pre-Data transfer stage */
842 		/* Spin lock for BUSY */
843 		w_ctr(ppb, 0x0c);
844 		if (!(r_str(ppb) & 0x80))
845 			return 1;
846 
847 		/* Require negotiation for read requests */
848 		x = (r_str(ppb) & 0xb8);
849 		dev->rd = (x & 0x10) ? 1 : 0;
850 		dev->dp = (x & 0x20) ? 0 : 1;
851 
852 		if ((dev->dp) && (dev->rd))
853 			if (imm_negotiate(dev))
854 				return 0;
855 		scsi_pointer->phase++;
856 		fallthrough;
857 
858 	case 6:		/* Phase 6 - Data transfer stage */
859 		/* Spin lock for BUSY */
860 		w_ctr(ppb, 0x0c);
861 		if (!(r_str(ppb) & 0x80))
862 			return 1;
863 
864 		if (dev->dp) {
865 			retv = imm_completion(cmd);
866 			if (retv == -1)
867 				return 0;
868 			if (retv == 0)
869 				return 1;
870 		}
871 		scsi_pointer->phase++;
872 		fallthrough;
873 
874 	case 7:		/* Phase 7 - Post data transfer stage */
875 		if ((dev->dp) && (dev->rd)) {
876 			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
877 				w_ctr(ppb, 0x4);
878 				w_ctr(ppb, 0xc);
879 				w_ctr(ppb, 0xe);
880 				w_ctr(ppb, 0x4);
881 			}
882 		}
883 		scsi_pointer->phase++;
884 		fallthrough;
885 
886 	case 8:		/* Phase 8 - Read status/message */
887 		/* Check for data overrun */
888 		if (imm_wait(dev) != (unsigned char) 0xb8) {
889 			imm_fail(dev, DID_ERROR);
890 			return 0;
891 		}
892 		if (imm_negotiate(dev))
893 			return 0;
894 		if (imm_in(dev, &l, 1)) {	/* read status byte */
895 			/* Check for optional message byte */
896 			if (imm_wait(dev) == (unsigned char) 0xb8)
897 				imm_in(dev, &h, 1);
898 			cmd->result = (DID_OK << 16) | (l & STATUS_MASK);
899 		}
900 		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
901 			w_ctr(ppb, 0x4);
902 			w_ctr(ppb, 0xc);
903 			w_ctr(ppb, 0xe);
904 			w_ctr(ppb, 0x4);
905 		}
906 		return 0;	/* Finished */
907 
908 	default:
909 		printk("imm: Invalid scsi phase\n");
910 	}
911 	return 0;
912 }
913 
914 static int imm_queuecommand_lck(struct scsi_cmnd *cmd)
915 {
916 	imm_struct *dev = imm_dev(cmd->device->host);
917 
918 	if (dev->cur_cmd) {
919 		printk("IMM: bug in imm_queuecommand\n");
920 		return 0;
921 	}
922 	dev->failed = 0;
923 	dev->jstart = jiffies;
924 	dev->cur_cmd = cmd;
925 	cmd->result = DID_ERROR << 16;	/* default return code */
926 	imm_scsi_pointer(cmd)->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 (imm_scsi_pointer(cmd)->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 	default:		/* SCSI command sent, can not abort */
971 		return FAILED;
972 	}
973 }
974 
975 static void imm_reset_pulse(unsigned int base)
976 {
977 	w_ctr(base, 0x04);
978 	w_dtr(base, 0x40);
979 	udelay(1);
980 	w_ctr(base, 0x0c);
981 	w_ctr(base, 0x0d);
982 	udelay(50);
983 	w_ctr(base, 0x0c);
984 	w_ctr(base, 0x04);
985 }
986 
987 static int imm_reset(struct scsi_cmnd *cmd)
988 {
989 	imm_struct *dev = imm_dev(cmd->device->host);
990 
991 	if (imm_scsi_pointer(cmd)->phase)
992 		imm_disconnect(dev);
993 	dev->cur_cmd = NULL;	/* Forget the problem */
994 
995 	imm_connect(dev, CONNECT_NORMAL);
996 	imm_reset_pulse(dev->base);
997 	mdelay(1);		/* device settle delay */
998 	imm_disconnect(dev);
999 	mdelay(1);		/* device settle delay */
1000 	return SUCCESS;
1001 }
1002 
1003 static int device_check(imm_struct *dev)
1004 {
1005 	/* This routine looks for a device and then attempts to use EPP
1006 	   to send a command. If all goes as planned then EPP is available. */
1007 
1008 	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
1009 	int loop, old_mode, status, k, ppb = dev->base;
1010 	unsigned char l;
1011 
1012 	old_mode = dev->mode;
1013 	for (loop = 0; loop < 8; loop++) {
1014 		/* Attempt to use EPP for Test Unit Ready */
1015 		if ((ppb & 0x0007) == 0x0000)
1016 			dev->mode = IMM_EPP_32;
1017 
1018 	      second_pass:
1019 		imm_connect(dev, CONNECT_EPP_MAYBE);
1020 		/* Select SCSI device */
1021 		if (!imm_select(dev, loop)) {
1022 			imm_disconnect(dev);
1023 			continue;
1024 		}
1025 		printk("imm: Found device at ID %i, Attempting to use %s\n",
1026 		       loop, IMM_MODE_STRING[dev->mode]);
1027 
1028 		/* Send SCSI command */
1029 		status = 1;
1030 		w_ctr(ppb, 0x0c);
1031 		for (l = 0; (l < 3) && (status); l++)
1032 			status = imm_out(dev, &cmd[l << 1], 2);
1033 
1034 		if (!status) {
1035 			imm_disconnect(dev);
1036 			imm_connect(dev, CONNECT_EPP_MAYBE);
1037 			imm_reset_pulse(dev->base);
1038 			udelay(1000);
1039 			imm_disconnect(dev);
1040 			udelay(1000);
1041 			if (dev->mode == IMM_EPP_32) {
1042 				dev->mode = old_mode;
1043 				goto second_pass;
1044 			}
1045 			printk("imm: Unable to establish communication\n");
1046 			return -EIO;
1047 		}
1048 		w_ctr(ppb, 0x0c);
1049 
1050 		k = 1000000;	/* 1 Second */
1051 		do {
1052 			l = r_str(ppb);
1053 			k--;
1054 			udelay(1);
1055 		} while (!(l & 0x80) && (k));
1056 
1057 		l &= 0xb8;
1058 
1059 		if (l != 0xb8) {
1060 			imm_disconnect(dev);
1061 			imm_connect(dev, CONNECT_EPP_MAYBE);
1062 			imm_reset_pulse(dev->base);
1063 			udelay(1000);
1064 			imm_disconnect(dev);
1065 			udelay(1000);
1066 			if (dev->mode == IMM_EPP_32) {
1067 				dev->mode = old_mode;
1068 				goto second_pass;
1069 			}
1070 			printk
1071 			    ("imm: Unable to establish communication\n");
1072 			return -EIO;
1073 		}
1074 		imm_disconnect(dev);
1075 		printk
1076 		    ("imm: Communication established at 0x%x with ID %i using %s\n",
1077 		     ppb, loop, IMM_MODE_STRING[dev->mode]);
1078 		imm_connect(dev, CONNECT_EPP_MAYBE);
1079 		imm_reset_pulse(dev->base);
1080 		udelay(1000);
1081 		imm_disconnect(dev);
1082 		udelay(1000);
1083 		return 0;
1084 	}
1085 	printk("imm: No devices found\n");
1086 	return -ENODEV;
1087 }
1088 
1089 /*
1090  * imm cannot deal with highmem, so this causes all IO pages for this host
1091  * to reside in low memory (hence mapped)
1092  */
1093 static int imm_adjust_queue(struct scsi_device *device)
1094 {
1095 	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1096 	return 0;
1097 }
1098 
1099 static struct scsi_host_template imm_template = {
1100 	.module			= THIS_MODULE,
1101 	.proc_name		= "imm",
1102 	.show_info		= imm_show_info,
1103 	.write_info		= imm_write_info,
1104 	.name			= "Iomega VPI2 (imm) interface",
1105 	.queuecommand		= imm_queuecommand,
1106 	.eh_abort_handler	= imm_abort,
1107 	.eh_host_reset_handler	= imm_reset,
1108 	.bios_param		= imm_biosparam,
1109 	.this_id		= 7,
1110 	.sg_tablesize		= SG_ALL,
1111 	.can_queue		= 1,
1112 	.slave_alloc		= imm_adjust_queue,
1113 	.cmd_size		= sizeof(struct scsi_pointer),
1114 };
1115 
1116 /***************************************************************************
1117  *                   Parallel port probing routines                        *
1118  ***************************************************************************/
1119 
1120 static LIST_HEAD(imm_hosts);
1121 
1122 /*
1123  * Finds the first available device number that can be alloted to the
1124  * new imm device and returns the address of the previous node so that
1125  * we can add to the tail and have a list in the ascending order.
1126  */
1127 
1128 static inline imm_struct *find_parent(void)
1129 {
1130 	imm_struct *dev, *par = NULL;
1131 	unsigned int cnt = 0;
1132 
1133 	if (list_empty(&imm_hosts))
1134 		return NULL;
1135 
1136 	list_for_each_entry(dev, &imm_hosts, list) {
1137 		if (dev->dev_no != cnt)
1138 			return par;
1139 		cnt++;
1140 		par = dev;
1141 	}
1142 
1143 	return par;
1144 }
1145 
1146 static int __imm_attach(struct parport *pb)
1147 {
1148 	struct Scsi_Host *host;
1149 	imm_struct *dev, *temp;
1150 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1151 	DEFINE_WAIT(wait);
1152 	int ports;
1153 	int modes, ppb;
1154 	int err = -ENOMEM;
1155 	struct pardev_cb imm_cb;
1156 
1157 	init_waitqueue_head(&waiting);
1158 
1159 	dev = kzalloc(sizeof(imm_struct), GFP_KERNEL);
1160 	if (!dev)
1161 		return -ENOMEM;
1162 
1163 
1164 	dev->base = -1;
1165 	dev->mode = IMM_AUTODETECT;
1166 	INIT_LIST_HEAD(&dev->list);
1167 
1168 	temp = find_parent();
1169 	if (temp)
1170 		dev->dev_no = temp->dev_no + 1;
1171 
1172 	memset(&imm_cb, 0, sizeof(imm_cb));
1173 	imm_cb.private = dev;
1174 	imm_cb.wakeup = imm_wakeup;
1175 
1176 	dev->dev = parport_register_dev_model(pb, "imm", &imm_cb, dev->dev_no);
1177 	if (!dev->dev)
1178 		goto out;
1179 
1180 
1181 	/* Claim the bus so it remembers what we do to the control
1182 	 * registers. [ CTR and ECP ]
1183 	 */
1184 	err = -EBUSY;
1185 	dev->waiting = &waiting;
1186 	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1187 	if (imm_pb_claim(dev))
1188 		schedule_timeout(3 * HZ);
1189 	if (dev->wanted) {
1190 		printk(KERN_ERR "imm%d: failed to claim parport because "
1191 			"a pardevice is owning the port for too long "
1192 			"time!\n", pb->number);
1193 		imm_pb_dismiss(dev);
1194 		dev->waiting = NULL;
1195 		finish_wait(&waiting, &wait);
1196 		goto out1;
1197 	}
1198 	dev->waiting = NULL;
1199 	finish_wait(&waiting, &wait);
1200 	ppb = dev->base = dev->dev->port->base;
1201 	dev->base_hi = dev->dev->port->base_hi;
1202 	w_ctr(ppb, 0x0c);
1203 	modes = dev->dev->port->modes;
1204 
1205 	/* Mode detection works up the chain of speed
1206 	 * This avoids a nasty if-then-else-if-... tree
1207 	 */
1208 	dev->mode = IMM_NIBBLE;
1209 
1210 	if (modes & PARPORT_MODE_TRISTATE)
1211 		dev->mode = IMM_PS2;
1212 
1213 	/* Done configuration */
1214 
1215 	err = imm_init(dev);
1216 
1217 	imm_pb_release(dev);
1218 
1219 	if (err)
1220 		goto out1;
1221 
1222 	/* now the glue ... */
1223 	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1224 		ports = 3;
1225 	else
1226 		ports = 8;
1227 
1228 	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1229 
1230 	err = -ENOMEM;
1231 	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1232 	if (!host)
1233 		goto out1;
1234 	host->io_port = pb->base;
1235 	host->n_io_port = ports;
1236 	host->dma_channel = -1;
1237 	host->unique_id = pb->number;
1238 	*(imm_struct **)&host->hostdata = dev;
1239 	dev->host = host;
1240 	if (!temp)
1241 		list_add_tail(&dev->list, &imm_hosts);
1242 	else
1243 		list_add_tail(&dev->list, &temp->list);
1244 	err = scsi_add_host(host, NULL);
1245 	if (err)
1246 		goto out2;
1247 	scsi_scan_host(host);
1248 	return 0;
1249 
1250 out2:
1251 	list_del_init(&dev->list);
1252 	scsi_host_put(host);
1253 out1:
1254 	parport_unregister_device(dev->dev);
1255 out:
1256 	kfree(dev);
1257 	return err;
1258 }
1259 
1260 static void imm_attach(struct parport *pb)
1261 {
1262 	__imm_attach(pb);
1263 }
1264 
1265 static void imm_detach(struct parport *pb)
1266 {
1267 	imm_struct *dev;
1268 	list_for_each_entry(dev, &imm_hosts, list) {
1269 		if (dev->dev->port == pb) {
1270 			list_del_init(&dev->list);
1271 			scsi_remove_host(dev->host);
1272 			scsi_host_put(dev->host);
1273 			parport_unregister_device(dev->dev);
1274 			kfree(dev);
1275 			break;
1276 		}
1277 	}
1278 }
1279 
1280 static struct parport_driver imm_driver = {
1281 	.name		= "imm",
1282 	.match_port	= imm_attach,
1283 	.detach		= imm_detach,
1284 	.devmodel	= true,
1285 };
1286 module_parport_driver(imm_driver);
1287 
1288 MODULE_LICENSE("GPL");
1289