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
35typedef 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
53static void imm_reset_pulse(unsigned int base);
54static int device_check(imm_struct *dev, bool autodetect);
55
56#include "imm.h"
57
58static unsigned int mode = IMM_AUTODETECT;
59module_param(mode, uint, 0644);
60MODULE_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
63static inline imm_struct *imm_dev(struct Scsi_Host *host)
64{
65	return *(imm_struct **)&host->hostdata;
66}
67
68static DEFINE_SPINLOCK(arbitration_lock);
69
70static 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
79static 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
94static 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
108static 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
120static 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 */
132static 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
144static 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);
157static inline void
158imm_fail_func(imm_struct *dev, int error_code)
159#else
160static inline void
161imm_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 */
178static 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
223static 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 */
274static 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 */
286static 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
303static 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
318static 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
337static 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
353static 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
399static 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
451static 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
521static 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
535static void imm_disconnect(imm_struct *dev)
536{
537	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
538}
539
540static 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
589static 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
615static 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 */
635static 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 */
733static 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
791static 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
928static 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
949static 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 */
957static 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
971static 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
989static 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
1001static 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
1017static 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/*
1104 * imm cannot deal with highmem, so this causes all IO pages for this host
1105 * to reside in low memory (hence mapped)
1106 */
1107static int imm_adjust_queue(struct scsi_device *device)
1108{
1109	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
1110	return 0;
1111}
1112
1113static const struct scsi_host_template imm_template = {
1114	.module			= THIS_MODULE,
1115	.proc_name		= "imm",
1116	.show_info		= imm_show_info,
1117	.write_info		= imm_write_info,
1118	.name			= "Iomega VPI2 (imm) interface",
1119	.queuecommand		= imm_queuecommand,
1120	.eh_abort_handler	= imm_abort,
1121	.eh_host_reset_handler	= imm_reset,
1122	.bios_param		= imm_biosparam,
1123	.this_id		= 7,
1124	.sg_tablesize		= SG_ALL,
1125	.can_queue		= 1,
1126	.slave_alloc		= imm_adjust_queue,
1127	.cmd_size		= sizeof(struct scsi_pointer),
1128};
1129
1130/***************************************************************************
1131 *                   Parallel port probing routines                        *
1132 ***************************************************************************/
1133
1134static LIST_HEAD(imm_hosts);
1135
1136/*
1137 * Finds the first available device number that can be alloted to the
1138 * new imm device and returns the address of the previous node so that
1139 * we can add to the tail and have a list in the ascending order.
1140 */
1141
1142static inline imm_struct *find_parent(void)
1143{
1144	imm_struct *dev, *par = NULL;
1145	unsigned int cnt = 0;
1146
1147	if (list_empty(&imm_hosts))
1148		return NULL;
1149
1150	list_for_each_entry(dev, &imm_hosts, list) {
1151		if (dev->dev_no != cnt)
1152			return par;
1153		cnt++;
1154		par = dev;
1155	}
1156
1157	return par;
1158}
1159
1160static int __imm_attach(struct parport *pb)
1161{
1162	struct Scsi_Host *host;
1163	imm_struct *dev, *temp;
1164	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1165	DEFINE_WAIT(wait);
1166	int ports;
1167	int err = -ENOMEM;
1168	struct pardev_cb imm_cb;
1169
1170	init_waitqueue_head(&waiting);
1171
1172	dev = kzalloc(sizeof(imm_struct), GFP_KERNEL);
1173	if (!dev)
1174		return -ENOMEM;
1175
1176
1177	dev->base = -1;
1178	dev->mode = mode < IMM_UNKNOWN ? mode : IMM_AUTODETECT;
1179	INIT_LIST_HEAD(&dev->list);
1180
1181	temp = find_parent();
1182	if (temp)
1183		dev->dev_no = temp->dev_no + 1;
1184
1185	memset(&imm_cb, 0, sizeof(imm_cb));
1186	imm_cb.private = dev;
1187	imm_cb.wakeup = imm_wakeup;
1188
1189	dev->dev = parport_register_dev_model(pb, "imm", &imm_cb, dev->dev_no);
1190	if (!dev->dev)
1191		goto out;
1192
1193
1194	/* Claim the bus so it remembers what we do to the control
1195	 * registers. [ CTR and ECP ]
1196	 */
1197	err = -EBUSY;
1198	dev->waiting = &waiting;
1199	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1200	if (imm_pb_claim(dev))
1201		schedule_timeout(3 * HZ);
1202	if (dev->wanted) {
1203		printk(KERN_ERR "imm%d: failed to claim parport because "
1204			"a pardevice is owning the port for too long "
1205			"time!\n", pb->number);
1206		imm_pb_dismiss(dev);
1207		dev->waiting = NULL;
1208		finish_wait(&waiting, &wait);
1209		goto out1;
1210	}
1211	dev->waiting = NULL;
1212	finish_wait(&waiting, &wait);
1213	dev->base = dev->dev->port->base;
1214	dev->base_hi = dev->dev->port->base_hi;
1215	w_ctr(dev->base, 0x0c);
1216
1217	/* Done configuration */
1218
1219	err = imm_init(dev);
1220
1221	imm_pb_release(dev);
1222
1223	if (err)
1224		goto out1;
1225
1226	/* now the glue ... */
1227	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
1228		ports = 3;
1229	else
1230		ports = 8;
1231
1232	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
1233
1234	err = -ENOMEM;
1235	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
1236	if (!host)
1237		goto out1;
1238	host->io_port = pb->base;
1239	host->n_io_port = ports;
1240	host->dma_channel = -1;
1241	host->unique_id = pb->number;
1242	*(imm_struct **)&host->hostdata = dev;
1243	dev->host = host;
1244	if (!temp)
1245		list_add_tail(&dev->list, &imm_hosts);
1246	else
1247		list_add_tail(&dev->list, &temp->list);
1248	err = scsi_add_host(host, NULL);
1249	if (err)
1250		goto out2;
1251	scsi_scan_host(host);
1252	return 0;
1253
1254out2:
1255	list_del_init(&dev->list);
1256	scsi_host_put(host);
1257out1:
1258	parport_unregister_device(dev->dev);
1259out:
1260	kfree(dev);
1261	return err;
1262}
1263
1264static void imm_attach(struct parport *pb)
1265{
1266	__imm_attach(pb);
1267}
1268
1269static void imm_detach(struct parport *pb)
1270{
1271	imm_struct *dev;
1272	list_for_each_entry(dev, &imm_hosts, list) {
1273		if (dev->dev->port == pb) {
1274			list_del_init(&dev->list);
1275			scsi_remove_host(dev->host);
1276			scsi_host_put(dev->host);
1277			parport_unregister_device(dev->dev);
1278			kfree(dev);
1279			break;
1280		}
1281	}
1282}
1283
1284static struct parport_driver imm_driver = {
1285	.name		= "imm",
1286	.match_port	= imm_attach,
1287	.detach		= imm_detach,
1288	.devmodel	= true,
1289};
1290module_parport_driver(imm_driver);
1291
1292MODULE_LICENSE("GPL");
1293