1/* ppa.c   --  low level driver for the IOMEGA PPA3
2 * parallel port SCSI host adapter.
3 *
4 * (The PPA3 is the embedded controller in the ZIP drive.)
5 *
6 * (c) 1995,1996 Grant R. Guenther, grant@torque.net,
7 * under the terms of the GNU General Public License.
8 *
9 */
10
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/blkdev.h>
15#include <linux/parport.h>
16#include <linux/workqueue.h>
17#include <linux/delay.h>
18#include <linux/jiffies.h>
19#include <asm/io.h>
20
21#include <scsi/scsi.h>
22#include <scsi/scsi_cmnd.h>
23#include <scsi/scsi_device.h>
24#include <scsi/scsi_host.h>
25
26
27static void ppa_reset_pulse(unsigned int base);
28
29typedef struct {
30	struct pardevice *dev;	/* Parport device entry         */
31	int base;		/* Actual port address          */
32	int mode;		/* Transfer mode                */
33	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
34	struct delayed_work ppa_tq;	/* Polling interrupt stuff       */
35	unsigned long jstart;	/* Jiffies at start             */
36	unsigned long recon_tmo;	/* How many usecs to wait for reconnection (6th bit) */
37	unsigned int failed:1;	/* Failure flag                 */
38	unsigned wanted:1;	/* Parport sharing busy flag    */
39	wait_queue_head_t *waiting;
40	struct Scsi_Host *host;
41	struct list_head list;
42} ppa_struct;
43
44#include  "ppa.h"
45
46static inline ppa_struct *ppa_dev(struct Scsi_Host *host)
47{
48	return *(ppa_struct **)&host->hostdata;
49}
50
51static DEFINE_SPINLOCK(arbitration_lock);
52
53static void got_it(ppa_struct *dev)
54{
55	dev->base = dev->dev->port->base;
56	if (dev->cur_cmd)
57		dev->cur_cmd->SCp.phase = 1;
58	else
59		wake_up(dev->waiting);
60}
61
62static void ppa_wakeup(void *ref)
63{
64	ppa_struct *dev = (ppa_struct *) ref;
65	unsigned long flags;
66
67	spin_lock_irqsave(&arbitration_lock, flags);
68	if (dev->wanted) {
69		parport_claim(dev->dev);
70		got_it(dev);
71		dev->wanted = 0;
72	}
73	spin_unlock_irqrestore(&arbitration_lock, flags);
74	return;
75}
76
77static int ppa_pb_claim(ppa_struct *dev)
78{
79	unsigned long flags;
80	int res = 1;
81	spin_lock_irqsave(&arbitration_lock, flags);
82	if (parport_claim(dev->dev) == 0) {
83		got_it(dev);
84		res = 0;
85	}
86	dev->wanted = res;
87	spin_unlock_irqrestore(&arbitration_lock, flags);
88	return res;
89}
90
91static void ppa_pb_dismiss(ppa_struct *dev)
92{
93	unsigned long flags;
94	int wanted;
95	spin_lock_irqsave(&arbitration_lock, flags);
96	wanted = dev->wanted;
97	dev->wanted = 0;
98	spin_unlock_irqrestore(&arbitration_lock, flags);
99	if (!wanted)
100		parport_release(dev->dev);
101}
102
103static inline void ppa_pb_release(ppa_struct *dev)
104{
105	parport_release(dev->dev);
106}
107
108/*
109 * Start of Chipset kludges
110 */
111
112/* This is to give the ppa driver a way to modify the timings (and other
113 * parameters) by writing to the /proc/scsi/ppa/0 file.
114 * Very simple method really... (To simple, no error checking :( )
115 * Reason: Kernel hackers HATE having to unload and reload modules for
116 * testing...
117 * Also gives a method to use a script to obtain optimum timings (TODO)
118 */
119
120static inline int ppa_proc_write(ppa_struct *dev, char *buffer, int length)
121{
122	unsigned long x;
123
124	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
125		x = simple_strtoul(buffer + 5, NULL, 0);
126		dev->mode = x;
127		return length;
128	}
129	if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
130		x = simple_strtoul(buffer + 10, NULL, 0);
131		dev->recon_tmo = x;
132		printk("ppa: recon_tmo set to %ld\n", x);
133		return length;
134	}
135	printk("ppa /proc: invalid variable\n");
136	return (-EINVAL);
137}
138
139static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
140{
141	int len = 0;
142	ppa_struct *dev = ppa_dev(host);
143
144	if (inout)
145		return ppa_proc_write(dev, buffer, length);
146
147	len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
148	len +=
149	    sprintf(buffer + len, "Parport : %s\n",
150		    dev->dev->port->name);
151	len +=
152	    sprintf(buffer + len, "Mode    : %s\n",
153		    PPA_MODE_STRING[dev->mode]);
154#if PPA_DEBUG > 0
155	len +=
156	    sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
157#endif
158
159	/* Request for beyond end of buffer */
160	if (offset > length)
161		return 0;
162
163	*start = buffer + offset;
164	len -= offset;
165	if (len > length)
166		len = length;
167	return len;
168}
169
170static int device_check(ppa_struct *dev);
171
172#if PPA_DEBUG > 0
173#define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
174	   y, __FUNCTION__, __LINE__); ppa_fail_func(x,y);
175static inline void ppa_fail_func(ppa_struct *dev, int error_code)
176#else
177static inline void ppa_fail(ppa_struct *dev, int error_code)
178#endif
179{
180	/* If we fail a device then we trash status / message bytes */
181	if (dev->cur_cmd) {
182		dev->cur_cmd->result = error_code << 16;
183		dev->failed = 1;
184	}
185}
186
187/*
188 * Wait for the high bit to be set.
189 *
190 * In principle, this could be tied to an interrupt, but the adapter
191 * doesn't appear to be designed to support interrupts.  We spin on
192 * the 0x80 ready bit.
193 */
194static unsigned char ppa_wait(ppa_struct *dev)
195{
196	int k;
197	unsigned short ppb = dev->base;
198	unsigned char r;
199
200	k = PPA_SPIN_TMO;
201	/* Wait for bit 6 and 7 - PJC */
202	for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
203		udelay(1);
204		r = r_str(ppb);
205	}
206
207	/*
208	 * return some status information.
209	 * Semantics: 0xc0 = ZIP wants more data
210	 *            0xd0 = ZIP wants to send more data
211	 *            0xe0 = ZIP is expecting SCSI command data
212	 *            0xf0 = end of transfer, ZIP is sending status
213	 */
214	if (k)
215		return (r & 0xf0);
216
217	/* Counter expired - Time out occurred */
218	ppa_fail(dev, DID_TIME_OUT);
219	printk("ppa timeout in ppa_wait\n");
220	return 0;		/* command timed out */
221}
222
223/*
224 * Clear EPP Timeout Bit
225 */
226static inline void epp_reset(unsigned short ppb)
227{
228	int i;
229
230	i = r_str(ppb);
231	w_str(ppb, i);
232	w_str(ppb, i & 0xfe);
233}
234
235/*
236 * Wait for empty ECP fifo (if we are in ECP fifo mode only)
237 */
238static inline void ecp_sync(ppa_struct *dev)
239{
240	int i, ppb_hi = dev->dev->port->base_hi;
241
242	if (ppb_hi == 0)
243		return;
244
245	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
246		for (i = 0; i < 100; i++) {
247			if (r_ecr(ppb_hi) & 0x01)
248				return;
249			udelay(5);
250		}
251		printk("ppa: ECP sync failed as data still present in FIFO.\n");
252	}
253}
254
255static int ppa_byte_out(unsigned short base, const char *buffer, int len)
256{
257	int i;
258
259	for (i = len; i; i--) {
260		w_dtr(base, *buffer++);
261		w_ctr(base, 0xe);
262		w_ctr(base, 0xc);
263	}
264	return 1;		/* All went well - we hope! */
265}
266
267static int ppa_byte_in(unsigned short base, char *buffer, int len)
268{
269	int i;
270
271	for (i = len; i; i--) {
272		*buffer++ = r_dtr(base);
273		w_ctr(base, 0x27);
274		w_ctr(base, 0x25);
275	}
276	return 1;		/* All went well - we hope! */
277}
278
279static int ppa_nibble_in(unsigned short base, char *buffer, int len)
280{
281	for (; len; len--) {
282		unsigned char h;
283
284		w_ctr(base, 0x4);
285		h = r_str(base) & 0xf0;
286		w_ctr(base, 0x6);
287		*buffer++ = h | ((r_str(base) & 0xf0) >> 4);
288	}
289	return 1;		/* All went well - we hope! */
290}
291
292static int ppa_out(ppa_struct *dev, char *buffer, int len)
293{
294	int r;
295	unsigned short ppb = dev->base;
296
297	r = ppa_wait(dev);
298
299	if ((r & 0x50) != 0x40) {
300		ppa_fail(dev, DID_ERROR);
301		return 0;
302	}
303	switch (dev->mode) {
304	case PPA_NIBBLE:
305	case PPA_PS2:
306		/* 8 bit output, with a loop */
307		r = ppa_byte_out(ppb, buffer, len);
308		break;
309
310	case PPA_EPP_32:
311	case PPA_EPP_16:
312	case PPA_EPP_8:
313		epp_reset(ppb);
314		w_ctr(ppb, 0x4);
315#ifdef CONFIG_SCSI_IZIP_EPP16
316		if (!(((long) buffer | len) & 0x01))
317			outsw(ppb + 4, buffer, len >> 1);
318#else
319		if (!(((long) buffer | len) & 0x03))
320			outsl(ppb + 4, buffer, len >> 2);
321#endif
322		else
323			outsb(ppb + 4, buffer, len);
324		w_ctr(ppb, 0xc);
325		r = !(r_str(ppb) & 0x01);
326		w_ctr(ppb, 0xc);
327		ecp_sync(dev);
328		break;
329
330	default:
331		printk("PPA: bug in ppa_out()\n");
332		r = 0;
333	}
334	return r;
335}
336
337static int ppa_in(ppa_struct *dev, char *buffer, int len)
338{
339	int r;
340	unsigned short ppb = dev->base;
341
342	r = ppa_wait(dev);
343
344	if ((r & 0x50) != 0x50) {
345		ppa_fail(dev, DID_ERROR);
346		return 0;
347	}
348	switch (dev->mode) {
349	case PPA_NIBBLE:
350		/* 4 bit input, with a loop */
351		r = ppa_nibble_in(ppb, buffer, len);
352		w_ctr(ppb, 0xc);
353		break;
354
355	case PPA_PS2:
356		/* 8 bit input, with a loop */
357		w_ctr(ppb, 0x25);
358		r = ppa_byte_in(ppb, buffer, len);
359		w_ctr(ppb, 0x4);
360		w_ctr(ppb, 0xc);
361		break;
362
363	case PPA_EPP_32:
364	case PPA_EPP_16:
365	case PPA_EPP_8:
366		epp_reset(ppb);
367		w_ctr(ppb, 0x24);
368#ifdef CONFIG_SCSI_IZIP_EPP16
369		if (!(((long) buffer | len) & 0x01))
370			insw(ppb + 4, buffer, len >> 1);
371#else
372		if (!(((long) buffer | len) & 0x03))
373			insl(ppb + 4, buffer, len >> 2);
374#endif
375		else
376			insb(ppb + 4, buffer, len);
377		w_ctr(ppb, 0x2c);
378		r = !(r_str(ppb) & 0x01);
379		w_ctr(ppb, 0x2c);
380		ecp_sync(dev);
381		break;
382
383	default:
384		printk("PPA: bug in ppa_ins()\n");
385		r = 0;
386		break;
387	}
388	return r;
389}
390
391/* end of ppa_io.h */
392static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
393{
394	w_dtr(ppb, b);
395	w_ctr(ppb, 0xc);
396	w_ctr(ppb, 0xe);
397	w_ctr(ppb, 0xc);
398	w_ctr(ppb, 0x4);
399	w_ctr(ppb, 0xc);
400}
401
402static void ppa_disconnect(ppa_struct *dev)
403{
404	unsigned short ppb = dev->base;
405
406	ppa_d_pulse(ppb, 0);
407	ppa_d_pulse(ppb, 0x3c);
408	ppa_d_pulse(ppb, 0x20);
409	ppa_d_pulse(ppb, 0xf);
410}
411
412static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
413{
414	w_dtr(ppb, b);
415	w_ctr(ppb, 0x4);
416	w_ctr(ppb, 0x6);
417	w_ctr(ppb, 0x4);
418	w_ctr(ppb, 0xc);
419}
420
421static inline void ppa_connect(ppa_struct *dev, int flag)
422{
423	unsigned short ppb = dev->base;
424
425	ppa_c_pulse(ppb, 0);
426	ppa_c_pulse(ppb, 0x3c);
427	ppa_c_pulse(ppb, 0x20);
428	if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
429		ppa_c_pulse(ppb, 0xcf);
430	else
431		ppa_c_pulse(ppb, 0x8f);
432}
433
434static int ppa_select(ppa_struct *dev, int target)
435{
436	int k;
437	unsigned short ppb = dev->base;
438
439	/*
440	 * Bit 6 (0x40) is the device selected bit.
441	 * First we must wait till the current device goes off line...
442	 */
443	k = PPA_SELECT_TMO;
444	do {
445		k--;
446		udelay(1);
447	} while ((r_str(ppb) & 0x40) && (k));
448	if (!k)
449		return 0;
450
451	w_dtr(ppb, (1 << target));
452	w_ctr(ppb, 0xe);
453	w_ctr(ppb, 0xc);
454	w_dtr(ppb, 0x80);	/* This is NOT the initator */
455	w_ctr(ppb, 0x8);
456
457	k = PPA_SELECT_TMO;
458	do {
459		k--;
460		udelay(1);
461	}
462	while (!(r_str(ppb) & 0x40) && (k));
463	if (!k)
464		return 0;
465
466	return 1;
467}
468
469/*
470 * This is based on a trace of what the Iomega DOS 'guest' driver does.
471 * I've tried several different kinds of parallel ports with guest and
472 * coded this to react in the same ways that it does.
473 *
474 * The return value from this function is just a hint about where the
475 * handshaking failed.
476 *
477 */
478static int ppa_init(ppa_struct *dev)
479{
480	int retv;
481	unsigned short ppb = dev->base;
482
483	ppa_disconnect(dev);
484	ppa_connect(dev, CONNECT_NORMAL);
485
486	retv = 2;		/* Failed */
487
488	w_ctr(ppb, 0xe);
489	if ((r_str(ppb) & 0x08) == 0x08)
490		retv--;
491
492	w_ctr(ppb, 0xc);
493	if ((r_str(ppb) & 0x08) == 0x00)
494		retv--;
495
496	if (!retv)
497		ppa_reset_pulse(ppb);
498	udelay(1000);		/* Allow devices to settle down */
499	ppa_disconnect(dev);
500	udelay(1000);		/* Another delay to allow devices to settle */
501
502	if (retv)
503		return -EIO;
504
505	return device_check(dev);
506}
507
508static inline int ppa_send_command(struct scsi_cmnd *cmd)
509{
510	ppa_struct *dev = ppa_dev(cmd->device->host);
511	int k;
512
513	w_ctr(dev->base, 0x0c);
514
515	for (k = 0; k < cmd->cmd_len; k++)
516		if (!ppa_out(dev, &cmd->cmnd[k], 1))
517			return 0;
518	return 1;
519}
520
521/*
522 * The bulk flag enables some optimisations in the data transfer loops,
523 * it should be true for any command that transfers data in integral
524 * numbers of sectors.
525 *
526 * The driver appears to remain stable if we speed up the parallel port
527 * i/o in this function, but not elsewhere.
528 */
529static int ppa_completion(struct scsi_cmnd *cmd)
530{
531	/* Return codes:
532	 * -1     Error
533	 *  0     Told to schedule
534	 *  1     Finished data transfer
535	 */
536	ppa_struct *dev = ppa_dev(cmd->device->host);
537	unsigned short ppb = dev->base;
538	unsigned long start_jiffies = jiffies;
539
540	unsigned char r, v;
541	int fast, bulk, status;
542
543	v = cmd->cmnd[0];
544	bulk = ((v == READ_6) ||
545		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
546
547	/*
548	 * We only get here if the drive is ready to comunicate,
549	 * hence no need for a full ppa_wait.
550	 */
551	r = (r_str(ppb) & 0xf0);
552
553	while (r != (unsigned char) 0xf0) {
554		/*
555		 * If we have been running for more than a full timer tick
556		 * then take a rest.
557		 */
558		if (time_after(jiffies, start_jiffies + 1))
559			return 0;
560
561		if ((cmd->SCp.this_residual <= 0)) {
562			ppa_fail(dev, DID_ERROR);
563			return -1;	/* ERROR_RETURN */
564		}
565
566		/* On some hardware we have SCSI disconnected (6th bit low)
567		 * for about 100usecs. It is too expensive to wait a
568		 * tick on every loop so we busy wait for no more than
569		 * 500usecs to give the drive a chance first. We do not
570		 * change things for "normal" hardware since generally
571		 * the 6th bit is always high.
572		 * This makes the CPU load higher on some hardware
573		 * but otherwise we can not get more than 50K/secs
574		 * on this problem hardware.
575		 */
576		if ((r & 0xc0) != 0xc0) {
577			/* Wait for reconnection should be no more than
578			 * jiffy/2 = 5ms = 5000 loops
579			 */
580			unsigned long k = dev->recon_tmo;
581			for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
582			     k--)
583				udelay(1);
584
585			if (!k)
586				return 0;
587		}
588
589		/* determine if we should use burst I/O */
590		fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
591		    ? PPA_BURST_SIZE : 1;
592
593		if (r == (unsigned char) 0xc0)
594			status = ppa_out(dev, cmd->SCp.ptr, fast);
595		else
596			status = ppa_in(dev, cmd->SCp.ptr, fast);
597
598		cmd->SCp.ptr += fast;
599		cmd->SCp.this_residual -= fast;
600
601		if (!status) {
602			ppa_fail(dev, DID_BUS_BUSY);
603			return -1;	/* ERROR_RETURN */
604		}
605		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
606			/* if scatter/gather, advance to the next segment */
607			if (cmd->SCp.buffers_residual--) {
608				cmd->SCp.buffer++;
609				cmd->SCp.this_residual =
610				    cmd->SCp.buffer->length;
611				cmd->SCp.ptr =
612				    page_address(cmd->SCp.buffer->page) +
613				    cmd->SCp.buffer->offset;
614			}
615		}
616		/* Now check to see if the drive is ready to comunicate */
617		r = (r_str(ppb) & 0xf0);
618		/* If not, drop back down to the scheduler and wait a timer tick */
619		if (!(r & 0x80))
620			return 0;
621	}
622	return 1;		/* FINISH_RETURN */
623}
624
625/*
626 * Since the PPA itself doesn't generate interrupts, we use
627 * the scheduler's task queue to generate a stream of call-backs and
628 * complete the request when the drive is ready.
629 */
630static void ppa_interrupt(struct work_struct *work)
631{
632	ppa_struct *dev = container_of(work, ppa_struct, ppa_tq.work);
633	struct scsi_cmnd *cmd = dev->cur_cmd;
634
635	if (!cmd) {
636		printk("PPA: bug in ppa_interrupt\n");
637		return;
638	}
639	if (ppa_engine(dev, cmd)) {
640		schedule_delayed_work(&dev->ppa_tq, 1);
641		return;
642	}
643	/* Command must of completed hence it is safe to let go... */
644#if PPA_DEBUG > 0
645	switch ((cmd->result >> 16) & 0xff) {
646	case DID_OK:
647		break;
648	case DID_NO_CONNECT:
649		printk("ppa: no device at SCSI ID %i\n", cmd->device->target);
650		break;
651	case DID_BUS_BUSY:
652		printk("ppa: BUS BUSY - EPP timeout detected\n");
653		break;
654	case DID_TIME_OUT:
655		printk("ppa: unknown timeout\n");
656		break;
657	case DID_ABORT:
658		printk("ppa: told to abort\n");
659		break;
660	case DID_PARITY:
661		printk("ppa: parity error (???)\n");
662		break;
663	case DID_ERROR:
664		printk("ppa: internal driver error\n");
665		break;
666	case DID_RESET:
667		printk("ppa: told to reset device\n");
668		break;
669	case DID_BAD_INTR:
670		printk("ppa: bad interrupt (???)\n");
671		break;
672	default:
673		printk("ppa: bad return code (%02x)\n",
674		       (cmd->result >> 16) & 0xff);
675	}
676#endif
677
678	if (cmd->SCp.phase > 1)
679		ppa_disconnect(dev);
680
681	ppa_pb_dismiss(dev);
682
683	dev->cur_cmd = NULL;
684
685	cmd->scsi_done(cmd);
686}
687
688static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
689{
690	unsigned short ppb = dev->base;
691	unsigned char l = 0, h = 0;
692	int retv;
693
694	/* First check for any errors that may of occurred
695	 * Here we check for internal errors
696	 */
697	if (dev->failed)
698		return 0;
699
700	switch (cmd->SCp.phase) {
701	case 0:		/* Phase 0 - Waiting for parport */
702		if (time_after(jiffies, dev->jstart + HZ)) {
703			/*
704			 * We waited more than a second
705			 * for parport to call us
706			 */
707			ppa_fail(dev, DID_BUS_BUSY);
708			return 0;
709		}
710		return 1;	/* wait until ppa_wakeup claims parport */
711	case 1:		/* Phase 1 - Connected */
712		{		/* Perform a sanity check for cable unplugged */
713			int retv = 2;	/* Failed */
714
715			ppa_connect(dev, CONNECT_EPP_MAYBE);
716
717			w_ctr(ppb, 0xe);
718			if ((r_str(ppb) & 0x08) == 0x08)
719				retv--;
720
721			w_ctr(ppb, 0xc);
722			if ((r_str(ppb) & 0x08) == 0x00)
723				retv--;
724
725			if (retv) {
726				if (time_after(jiffies, dev->jstart + (1 * HZ))) {
727					printk
728					    ("ppa: Parallel port cable is unplugged!!\n");
729					ppa_fail(dev, DID_BUS_BUSY);
730					return 0;
731				} else {
732					ppa_disconnect(dev);
733					return 1;	/* Try again in a jiffy */
734				}
735			}
736			cmd->SCp.phase++;
737		}
738
739	case 2:		/* Phase 2 - We are now talking to the scsi bus */
740		if (!ppa_select(dev, scmd_id(cmd))) {
741			ppa_fail(dev, DID_NO_CONNECT);
742			return 0;
743		}
744		cmd->SCp.phase++;
745
746	case 3:		/* Phase 3 - Ready to accept a command */
747		w_ctr(ppb, 0x0c);
748		if (!(r_str(ppb) & 0x80))
749			return 1;
750
751		if (!ppa_send_command(cmd))
752			return 0;
753		cmd->SCp.phase++;
754
755	case 4:		/* Phase 4 - Setup scatter/gather buffers */
756		if (cmd->use_sg) {
757			/* if many buffers are available, start filling the first */
758			cmd->SCp.buffer =
759			    (struct scatterlist *) cmd->request_buffer;
760			cmd->SCp.this_residual = cmd->SCp.buffer->length;
761			cmd->SCp.ptr =
762			    page_address(cmd->SCp.buffer->page) +
763			    cmd->SCp.buffer->offset;
764		} else {
765			/* else fill the only available buffer */
766			cmd->SCp.buffer = NULL;
767			cmd->SCp.this_residual = cmd->request_bufflen;
768			cmd->SCp.ptr = cmd->request_buffer;
769		}
770		cmd->SCp.buffers_residual = cmd->use_sg - 1;
771		cmd->SCp.phase++;
772
773	case 5:		/* Phase 5 - Data transfer stage */
774		w_ctr(ppb, 0x0c);
775		if (!(r_str(ppb) & 0x80))
776			return 1;
777
778		retv = ppa_completion(cmd);
779		if (retv == -1)
780			return 0;
781		if (retv == 0)
782			return 1;
783		cmd->SCp.phase++;
784
785	case 6:		/* Phase 6 - Read status/message */
786		cmd->result = DID_OK << 16;
787		/* Check for data overrun */
788		if (ppa_wait(dev) != (unsigned char) 0xf0) {
789			ppa_fail(dev, DID_ERROR);
790			return 0;
791		}
792		if (ppa_in(dev, &l, 1)) {	/* read status byte */
793			/* Check for optional message byte */
794			if (ppa_wait(dev) == (unsigned char) 0xf0)
795				ppa_in(dev, &h, 1);
796			cmd->result =
797			    (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
798		}
799		return 0;	/* Finished */
800		break;
801
802	default:
803		printk("ppa: Invalid scsi phase\n");
804	}
805	return 0;
806}
807
808static int ppa_queuecommand(struct scsi_cmnd *cmd,
809		void (*done) (struct scsi_cmnd *))
810{
811	ppa_struct *dev = ppa_dev(cmd->device->host);
812
813	if (dev->cur_cmd) {
814		printk("PPA: bug in ppa_queuecommand\n");
815		return 0;
816	}
817	dev->failed = 0;
818	dev->jstart = jiffies;
819	dev->cur_cmd = cmd;
820	cmd->scsi_done = done;
821	cmd->result = DID_ERROR << 16;	/* default return code */
822	cmd->SCp.phase = 0;	/* bus free */
823
824	schedule_delayed_work(&dev->ppa_tq, 0);
825
826	ppa_pb_claim(dev);
827
828	return 0;
829}
830
831/*
832 * Apparently the disk->capacity attribute is off by 1 sector
833 * for all disk drives.  We add the one here, but it should really
834 * be done in sd.c.  Even if it gets fixed there, this will still
835 * work.
836 */
837static int ppa_biosparam(struct scsi_device *sdev, struct block_device *dev,
838	      sector_t capacity, int ip[])
839{
840	ip[0] = 0x40;
841	ip[1] = 0x20;
842	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
843	if (ip[2] > 1024) {
844		ip[0] = 0xff;
845		ip[1] = 0x3f;
846		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
847		if (ip[2] > 1023)
848			ip[2] = 1023;
849	}
850	return 0;
851}
852
853static int ppa_abort(struct scsi_cmnd *cmd)
854{
855	ppa_struct *dev = ppa_dev(cmd->device->host);
856	/*
857	 * There is no method for aborting commands since Iomega
858	 * have tied the SCSI_MESSAGE line high in the interface
859	 */
860
861	switch (cmd->SCp.phase) {
862	case 0:		/* Do not have access to parport */
863	case 1:		/* Have not connected to interface */
864		dev->cur_cmd = NULL;	/* Forget the problem */
865		return SUCCESS;
866		break;
867	default:		/* SCSI command sent, can not abort */
868		return FAILED;
869		break;
870	}
871}
872
873static void ppa_reset_pulse(unsigned int base)
874{
875	w_dtr(base, 0x40);
876	w_ctr(base, 0x8);
877	udelay(30);
878	w_ctr(base, 0xc);
879}
880
881static int ppa_reset(struct scsi_cmnd *cmd)
882{
883	ppa_struct *dev = ppa_dev(cmd->device->host);
884
885	if (cmd->SCp.phase)
886		ppa_disconnect(dev);
887	dev->cur_cmd = NULL;	/* Forget the problem */
888
889	ppa_connect(dev, CONNECT_NORMAL);
890	ppa_reset_pulse(dev->base);
891	mdelay(1);		/* device settle delay */
892	ppa_disconnect(dev);
893	mdelay(1);		/* device settle delay */
894	return SUCCESS;
895}
896
897static int device_check(ppa_struct *dev)
898{
899	/* This routine looks for a device and then attempts to use EPP
900	   to send a command. If all goes as planned then EPP is available. */
901
902	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
903	int loop, old_mode, status, k, ppb = dev->base;
904	unsigned char l;
905
906	old_mode = dev->mode;
907	for (loop = 0; loop < 8; loop++) {
908		/* Attempt to use EPP for Test Unit Ready */
909		if ((ppb & 0x0007) == 0x0000)
910			dev->mode = PPA_EPP_32;
911
912	      second_pass:
913		ppa_connect(dev, CONNECT_EPP_MAYBE);
914		/* Select SCSI device */
915		if (!ppa_select(dev, loop)) {
916			ppa_disconnect(dev);
917			continue;
918		}
919		printk("ppa: Found device at ID %i, Attempting to use %s\n",
920		       loop, PPA_MODE_STRING[dev->mode]);
921
922		/* Send SCSI command */
923		status = 1;
924		w_ctr(ppb, 0x0c);
925		for (l = 0; (l < 6) && (status); l++)
926			status = ppa_out(dev, cmd, 1);
927
928		if (!status) {
929			ppa_disconnect(dev);
930			ppa_connect(dev, CONNECT_EPP_MAYBE);
931			w_dtr(ppb, 0x40);
932			w_ctr(ppb, 0x08);
933			udelay(30);
934			w_ctr(ppb, 0x0c);
935			udelay(1000);
936			ppa_disconnect(dev);
937			udelay(1000);
938			if (dev->mode == PPA_EPP_32) {
939				dev->mode = old_mode;
940				goto second_pass;
941			}
942			return -EIO;
943		}
944		w_ctr(ppb, 0x0c);
945		k = 1000000;	/* 1 Second */
946		do {
947			l = r_str(ppb);
948			k--;
949			udelay(1);
950		} while (!(l & 0x80) && (k));
951
952		l &= 0xf0;
953
954		if (l != 0xf0) {
955			ppa_disconnect(dev);
956			ppa_connect(dev, CONNECT_EPP_MAYBE);
957			ppa_reset_pulse(ppb);
958			udelay(1000);
959			ppa_disconnect(dev);
960			udelay(1000);
961			if (dev->mode == PPA_EPP_32) {
962				dev->mode = old_mode;
963				goto second_pass;
964			}
965			return -EIO;
966		}
967		ppa_disconnect(dev);
968		printk("ppa: Communication established with ID %i using %s\n",
969		       loop, PPA_MODE_STRING[dev->mode]);
970		ppa_connect(dev, CONNECT_EPP_MAYBE);
971		ppa_reset_pulse(ppb);
972		udelay(1000);
973		ppa_disconnect(dev);
974		udelay(1000);
975		return 0;
976	}
977	return -ENODEV;
978}
979
980static int ppa_adjust_queue(struct scsi_device *device)
981{
982	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
983	return 0;
984}
985
986static struct scsi_host_template ppa_template = {
987	.module			= THIS_MODULE,
988	.proc_name		= "ppa",
989	.proc_info		= ppa_proc_info,
990	.name			= "Iomega VPI0 (ppa) interface",
991	.queuecommand		= ppa_queuecommand,
992	.eh_abort_handler	= ppa_abort,
993	.eh_bus_reset_handler	= ppa_reset,
994	.eh_host_reset_handler	= ppa_reset,
995	.bios_param		= ppa_biosparam,
996	.this_id		= -1,
997	.sg_tablesize		= SG_ALL,
998	.cmd_per_lun		= 1,
999	.use_clustering		= ENABLE_CLUSTERING,
1000	.can_queue		= 1,
1001	.slave_alloc		= ppa_adjust_queue,
1002};
1003
1004/***************************************************************************
1005 *                   Parallel port probing routines                        *
1006 ***************************************************************************/
1007
1008static LIST_HEAD(ppa_hosts);
1009
1010static int __ppa_attach(struct parport *pb)
1011{
1012	struct Scsi_Host *host;
1013	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
1014	DEFINE_WAIT(wait);
1015	ppa_struct *dev;
1016	int ports;
1017	int modes, ppb, ppb_hi;
1018	int err = -ENOMEM;
1019
1020	dev = kmalloc(sizeof(ppa_struct), GFP_KERNEL);
1021	if (!dev)
1022		return -ENOMEM;
1023	memset(dev, 0, sizeof(ppa_struct));
1024	dev->base = -1;
1025	dev->mode = PPA_AUTODETECT;
1026	dev->recon_tmo = PPA_RECON_TMO;
1027	init_waitqueue_head(&waiting);
1028	dev->dev = parport_register_device(pb, "ppa", NULL, ppa_wakeup,
1029					    NULL, 0, dev);
1030
1031	if (!dev->dev)
1032		goto out;
1033
1034	/* Claim the bus so it remembers what we do to the control
1035	 * registers. [ CTR and ECP ]
1036	 */
1037	err = -EBUSY;
1038	dev->waiting = &waiting;
1039	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1040	if (ppa_pb_claim(dev))
1041		schedule_timeout(3 * HZ);
1042	if (dev->wanted) {
1043		printk(KERN_ERR "ppa%d: failed to claim parport because "
1044				"a pardevice is owning the port for too long "
1045				"time!\n", pb->number);
1046		ppa_pb_dismiss(dev);
1047		dev->waiting = NULL;
1048		finish_wait(&waiting, &wait);
1049		goto out1;
1050	}
1051	dev->waiting = NULL;
1052	finish_wait(&waiting, &wait);
1053	ppb = dev->base = dev->dev->port->base;
1054	ppb_hi = dev->dev->port->base_hi;
1055	w_ctr(ppb, 0x0c);
1056	modes = dev->dev->port->modes;
1057
1058	/* Mode detection works up the chain of speed
1059	 * This avoids a nasty if-then-else-if-... tree
1060	 */
1061	dev->mode = PPA_NIBBLE;
1062
1063	if (modes & PARPORT_MODE_TRISTATE)
1064		dev->mode = PPA_PS2;
1065
1066	if (modes & PARPORT_MODE_ECP) {
1067		w_ecr(ppb_hi, 0x20);
1068		dev->mode = PPA_PS2;
1069	}
1070	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
1071		w_ecr(ppb_hi, 0x80);
1072
1073	/* Done configuration */
1074
1075	err = ppa_init(dev);
1076	ppa_pb_release(dev);
1077
1078	if (err)
1079		goto out1;
1080
1081	/* now the glue ... */
1082	if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
1083		ports = 3;
1084	else
1085		ports = 8;
1086
1087	INIT_DELAYED_WORK(&dev->ppa_tq, ppa_interrupt);
1088
1089	err = -ENOMEM;
1090	host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
1091	if (!host)
1092		goto out1;
1093	host->io_port = pb->base;
1094	host->n_io_port = ports;
1095	host->dma_channel = -1;
1096	host->unique_id = pb->number;
1097	*(ppa_struct **)&host->hostdata = dev;
1098	dev->host = host;
1099	list_add_tail(&dev->list, &ppa_hosts);
1100	err = scsi_add_host(host, NULL);
1101	if (err)
1102		goto out2;
1103	scsi_scan_host(host);
1104	return 0;
1105out2:
1106	list_del_init(&dev->list);
1107	scsi_host_put(host);
1108out1:
1109	parport_unregister_device(dev->dev);
1110out:
1111	kfree(dev);
1112	return err;
1113}
1114
1115static void ppa_attach(struct parport *pb)
1116{
1117	__ppa_attach(pb);
1118}
1119
1120static void ppa_detach(struct parport *pb)
1121{
1122	ppa_struct *dev;
1123	list_for_each_entry(dev, &ppa_hosts, list) {
1124		if (dev->dev->port == pb) {
1125			list_del_init(&dev->list);
1126			scsi_remove_host(dev->host);
1127			scsi_host_put(dev->host);
1128			parport_unregister_device(dev->dev);
1129			kfree(dev);
1130			break;
1131		}
1132	}
1133}
1134
1135static struct parport_driver ppa_driver = {
1136	.name	= "ppa",
1137	.attach	= ppa_attach,
1138	.detach	= ppa_detach,
1139};
1140
1141static int __init ppa_driver_init(void)
1142{
1143	printk("ppa: Version %s\n", PPA_VERSION);
1144	return parport_register_driver(&ppa_driver);
1145}
1146
1147static void __exit ppa_driver_exit(void)
1148{
1149	parport_unregister_driver(&ppa_driver);
1150}
1151
1152module_init(ppa_driver_init);
1153module_exit(ppa_driver_exit);
1154MODULE_LICENSE("GPL");
1155