xref: /openbmc/linux/drivers/scsi/atari_scsi.c (revision 4800cd83)
1 /*
2  * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
3  *
4  * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
5  *
6  *   Loosely based on the work of Robert De Vries' team and added:
7  *    - working real DMA
8  *    - Falcon support (untested yet!)   ++bjoern fixed and now it works
9  *    - lots of extensions and bug fixes.
10  *
11  * This file is subject to the terms and conditions of the GNU General Public
12  * License.  See the file COPYING in the main directory of this archive
13  * for more details.
14  *
15  */
16 
17 
18 /**************************************************************************/
19 /*                                                                        */
20 /* Notes for Falcon SCSI:                                                 */
21 /* ----------------------                                                 */
22 /*                                                                        */
23 /* Since the Falcon SCSI uses the ST-DMA chip, that is shared among       */
24 /* several device drivers, locking and unlocking the access to this       */
25 /* chip is required. But locking is not possible from an interrupt,       */
26 /* since it puts the process to sleep if the lock is not available.       */
27 /* This prevents "late" locking of the DMA chip, i.e. locking it just     */
28 /* before using it, since in case of disconnection-reconnection           */
29 /* commands, the DMA is started from the reselection interrupt.           */
30 /*                                                                        */
31 /* Two possible schemes for ST-DMA-locking would be:                      */
32 /*  1) The lock is taken for each command separately and disconnecting    */
33 /*     is forbidden (i.e. can_queue = 1).                                 */
34 /*  2) The DMA chip is locked when the first command comes in and         */
35 /*     released when the last command is finished and all queues are      */
36 /*     empty.                                                             */
37 /* The first alternative would result in bad performance, since the       */
38 /* interleaving of commands would not be used. The second is unfair to    */
39 /* other drivers using the ST-DMA, because the queues will seldom be      */
40 /* totally empty if there is a lot of disk traffic.                       */
41 /*                                                                        */
42 /* For this reasons I decided to employ a more elaborate scheme:          */
43 /*  - First, we give up the lock every time we can (for fairness), this    */
44 /*    means every time a command finishes and there are no other commands */
45 /*    on the disconnected queue.                                          */
46 /*  - If there are others waiting to lock the DMA chip, we stop           */
47 /*    issuing commands, i.e. moving them onto the issue queue.           */
48 /*    Because of that, the disconnected queue will run empty in a         */
49 /*    while. Instead we go to sleep on a 'fairness_queue'.                */
50 /*  - If the lock is released, all processes waiting on the fairness      */
51 /*    queue will be woken. The first of them tries to re-lock the DMA,     */
52 /*    the others wait for the first to finish this task. After that,      */
53 /*    they can all run on and do their commands...                        */
54 /* This sounds complicated (and it is it :-(), but it seems to be a       */
55 /* good compromise between fairness and performance: As long as no one     */
56 /* else wants to work with the ST-DMA chip, SCSI can go along as          */
57 /* usual. If now someone else comes, this behaviour is changed to a       */
58 /* "fairness mode": just already initiated commands are finished and      */
59 /* then the lock is released. The other one waiting will probably win     */
60 /* the race for locking the DMA, since it was waiting for longer. And     */
61 /* after it has finished, SCSI can go ahead again. Finally: I hope I      */
62 /* have not produced any deadlock possibilities!                          */
63 /*                                                                        */
64 /**************************************************************************/
65 
66 
67 
68 #include <linux/module.h>
69 
70 #define NDEBUG (0)
71 
72 #define NDEBUG_ABORT		0x00100000
73 #define NDEBUG_TAGS		0x00200000
74 #define NDEBUG_MERGING		0x00400000
75 
76 #define AUTOSENSE
77 /* For the Atari version, use only polled IO or REAL_DMA */
78 #define	REAL_DMA
79 /* Support tagged queuing? (on devices that are able to... :-) */
80 #define	SUPPORT_TAGS
81 #define	MAX_TAGS 32
82 
83 #include <linux/types.h>
84 #include <linux/stddef.h>
85 #include <linux/ctype.h>
86 #include <linux/delay.h>
87 #include <linux/mm.h>
88 #include <linux/blkdev.h>
89 #include <linux/interrupt.h>
90 #include <linux/init.h>
91 #include <linux/nvram.h>
92 #include <linux/bitops.h>
93 
94 #include <asm/setup.h>
95 #include <asm/atarihw.h>
96 #include <asm/atariints.h>
97 #include <asm/page.h>
98 #include <asm/pgtable.h>
99 #include <asm/irq.h>
100 #include <asm/traps.h>
101 
102 #include "scsi.h"
103 #include <scsi/scsi_host.h>
104 #include "atari_scsi.h"
105 #include "NCR5380.h"
106 #include <asm/atari_stdma.h>
107 #include <asm/atari_stram.h>
108 #include <asm/io.h>
109 
110 #include <linux/stat.h>
111 
112 #define	IS_A_TT()	ATARIHW_PRESENT(TT_SCSI)
113 
114 #define	SCSI_DMA_WRITE_P(elt,val)				\
115 	do {							\
116 		unsigned long v = val;				\
117 		tt_scsi_dma.elt##_lo = v & 0xff;		\
118 		v >>= 8;					\
119 		tt_scsi_dma.elt##_lmd = v & 0xff;		\
120 		v >>= 8;					\
121 		tt_scsi_dma.elt##_hmd = v & 0xff;		\
122 		v >>= 8;					\
123 		tt_scsi_dma.elt##_hi = v & 0xff;		\
124 	} while(0)
125 
126 #define	SCSI_DMA_READ_P(elt)					\
127 	(((((((unsigned long)tt_scsi_dma.elt##_hi << 8) |	\
128 	     (unsigned long)tt_scsi_dma.elt##_hmd) << 8) |	\
129 	   (unsigned long)tt_scsi_dma.elt##_lmd) << 8) |	\
130 	 (unsigned long)tt_scsi_dma.elt##_lo)
131 
132 
133 static inline void SCSI_DMA_SETADR(unsigned long adr)
134 {
135 	st_dma.dma_lo = (unsigned char)adr;
136 	MFPDELAY();
137 	adr >>= 8;
138 	st_dma.dma_md = (unsigned char)adr;
139 	MFPDELAY();
140 	adr >>= 8;
141 	st_dma.dma_hi = (unsigned char)adr;
142 	MFPDELAY();
143 }
144 
145 static inline unsigned long SCSI_DMA_GETADR(void)
146 {
147 	unsigned long adr;
148 	adr = st_dma.dma_lo;
149 	MFPDELAY();
150 	adr |= (st_dma.dma_md & 0xff) << 8;
151 	MFPDELAY();
152 	adr |= (st_dma.dma_hi & 0xff) << 16;
153 	MFPDELAY();
154 	return adr;
155 }
156 
157 static inline void ENABLE_IRQ(void)
158 {
159 	if (IS_A_TT())
160 		atari_enable_irq(IRQ_TT_MFP_SCSI);
161 	else
162 		atari_enable_irq(IRQ_MFP_FSCSI);
163 }
164 
165 static inline void DISABLE_IRQ(void)
166 {
167 	if (IS_A_TT())
168 		atari_disable_irq(IRQ_TT_MFP_SCSI);
169 	else
170 		atari_disable_irq(IRQ_MFP_FSCSI);
171 }
172 
173 
174 #define HOSTDATA_DMALEN		(((struct NCR5380_hostdata *) \
175 				(atari_scsi_host->hostdata))->dma_len)
176 
177 /* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
178  * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
179  * need ten times the standard value... */
180 #ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
181 #define	AFTER_RESET_DELAY	(HZ/2)
182 #else
183 #define	AFTER_RESET_DELAY	(5*HZ/2)
184 #endif
185 
186 /***************************** Prototypes *****************************/
187 
188 #ifdef REAL_DMA
189 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat);
190 static void atari_scsi_fetch_restbytes(void);
191 static long atari_scsi_dma_residual(struct Scsi_Host *instance);
192 static int falcon_classify_cmd(Scsi_Cmnd *cmd);
193 static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
194 					Scsi_Cmnd *cmd, int write_flag);
195 #endif
196 static irqreturn_t scsi_tt_intr(int irq, void *dummy);
197 static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
198 static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
199 static void falcon_get_lock(void);
200 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
201 static void atari_scsi_reset_boot(void);
202 #endif
203 static unsigned char atari_scsi_tt_reg_read(unsigned char reg);
204 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value);
205 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg);
206 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value);
207 
208 /************************* End of Prototypes **************************/
209 
210 
211 static struct Scsi_Host *atari_scsi_host;
212 static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
213 static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
214 
215 #ifdef REAL_DMA
216 static unsigned long	atari_dma_residual, atari_dma_startaddr;
217 static short		atari_dma_active;
218 /* pointer to the dribble buffer */
219 static char		*atari_dma_buffer;
220 /* precalculated physical address of the dribble buffer */
221 static unsigned long	atari_dma_phys_buffer;
222 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */
223 static char		*atari_dma_orig_addr;
224 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
225  * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
226  * cases where requests to physical contiguous buffers have been merged, this
227  * request is <= 4k (one page). So I don't think we have to split transfers
228  * just due to this buffer size...
229  */
230 #define	STRAM_BUFFER_SIZE	(4096)
231 /* mask for address bits that can't be used with the ST-DMA */
232 static unsigned long	atari_dma_stram_mask;
233 #define STRAM_ADDR(a)	(((a) & atari_dma_stram_mask) == 0)
234 /* number of bytes to cut from a transfer to handle NCR overruns */
235 static int atari_read_overruns;
236 #endif
237 
238 static int setup_can_queue = -1;
239 module_param(setup_can_queue, int, 0);
240 static int setup_cmd_per_lun = -1;
241 module_param(setup_cmd_per_lun, int, 0);
242 static int setup_sg_tablesize = -1;
243 module_param(setup_sg_tablesize, int, 0);
244 #ifdef SUPPORT_TAGS
245 static int setup_use_tagged_queuing = -1;
246 module_param(setup_use_tagged_queuing, int, 0);
247 #endif
248 static int setup_hostid = -1;
249 module_param(setup_hostid, int, 0);
250 
251 
252 #if defined(REAL_DMA)
253 
254 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
255 {
256 	int i;
257 	unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
258 
259 	if (dma_stat & 0x01) {
260 
261 		/* A bus error happens when DMA-ing from the last page of a
262 		 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
263 		 * Check for this case:
264 		 */
265 
266 		for (i = 0; i < m68k_num_memory; ++i) {
267 			end_addr = m68k_memory[i].addr + m68k_memory[i].size;
268 			if (end_addr <= addr && addr <= end_addr + 4)
269 				return 1;
270 		}
271 	}
272 	return 0;
273 }
274 
275 
276 #if 0
277 /* Dead code... wasn't called anyway :-) and causes some trouble, because at
278  * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
279  * to clear the DMA int pending bit before it allows other level 6 interrupts.
280  */
281 static void scsi_dma_buserr(int irq, void *dummy)
282 {
283 	unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
284 
285 	/* Don't do anything if a NCR interrupt is pending. Probably it's just
286 	 * masked... */
287 	if (atari_irq_pending(IRQ_TT_MFP_SCSI))
288 		return;
289 
290 	printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
291 	       SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
292 	if (dma_stat & 0x80) {
293 		if (!scsi_dma_is_ignored_buserr(dma_stat))
294 			printk("SCSI DMA bus error -- bad DMA programming!\n");
295 	} else {
296 		/* Under normal circumstances we never should get to this point,
297 		 * since both interrupts are triggered simultaneously and the 5380
298 		 * int has higher priority. When this irq is handled, that DMA
299 		 * interrupt is cleared. So a warning message is printed here.
300 		 */
301 		printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
302 	}
303 }
304 #endif
305 
306 #endif
307 
308 
309 static irqreturn_t scsi_tt_intr(int irq, void *dummy)
310 {
311 #ifdef REAL_DMA
312 	int dma_stat;
313 
314 	dma_stat = tt_scsi_dma.dma_ctrl;
315 
316 	INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n",
317 		   atari_scsi_host->host_no, dma_stat & 0xff);
318 
319 	/* Look if it was the DMA that has interrupted: First possibility
320 	 * is that a bus error occurred...
321 	 */
322 	if (dma_stat & 0x80) {
323 		if (!scsi_dma_is_ignored_buserr(dma_stat)) {
324 			printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
325 			       SCSI_DMA_READ_P(dma_addr));
326 			printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
327 		}
328 	}
329 
330 	/* If the DMA is active but not finished, we have the case
331 	 * that some other 5380 interrupt occurred within the DMA transfer.
332 	 * This means we have residual bytes, if the desired end address
333 	 * is not yet reached. Maybe we have to fetch some bytes from the
334 	 * rest data register, too. The residual must be calculated from
335 	 * the address pointer, not the counter register, because only the
336 	 * addr reg counts bytes not yet written and pending in the rest
337 	 * data reg!
338 	 */
339 	if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
340 		atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
341 
342 		DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
343 			   atari_dma_residual);
344 
345 		if ((signed int)atari_dma_residual < 0)
346 			atari_dma_residual = 0;
347 		if ((dma_stat & 1) == 0) {
348 			/*
349 			 * After read operations, we maybe have to
350 			 * transport some rest bytes
351 			 */
352 			atari_scsi_fetch_restbytes();
353 		} else {
354 			/*
355 			 * There seems to be a nasty bug in some SCSI-DMA/NCR
356 			 * combinations: If a target disconnects while a write
357 			 * operation is going on, the address register of the
358 			 * DMA may be a few bytes farer than it actually read.
359 			 * This is probably due to DMA prefetching and a delay
360 			 * between DMA and NCR.  Experiments showed that the
361 			 * dma_addr is 9 bytes to high, but this could vary.
362 			 * The problem is, that the residual is thus calculated
363 			 * wrong and the next transfer will start behind where
364 			 * it should.  So we round up the residual to the next
365 			 * multiple of a sector size, if it isn't already a
366 			 * multiple and the originally expected transfer size
367 			 * was.  The latter condition is there to ensure that
368 			 * the correction is taken only for "real" data
369 			 * transfers and not for, e.g., the parameters of some
370 			 * other command.  These shouldn't disconnect anyway.
371 			 */
372 			if (atari_dma_residual & 0x1ff) {
373 				DMA_PRINTK("SCSI DMA: DMA bug corrected, "
374 					   "difference %ld bytes\n",
375 					   512 - (atari_dma_residual & 0x1ff));
376 				atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
377 			}
378 		}
379 		tt_scsi_dma.dma_ctrl = 0;
380 	}
381 
382 	/* If the DMA is finished, fetch the rest bytes and turn it off */
383 	if (dma_stat & 0x40) {
384 		atari_dma_residual = 0;
385 		if ((dma_stat & 1) == 0)
386 			atari_scsi_fetch_restbytes();
387 		tt_scsi_dma.dma_ctrl = 0;
388 	}
389 
390 #endif /* REAL_DMA */
391 
392 	NCR5380_intr(irq, dummy);
393 
394 #if 0
395 	/* To be sure the int is not masked */
396 	atari_enable_irq(IRQ_TT_MFP_SCSI);
397 #endif
398 	return IRQ_HANDLED;
399 }
400 
401 
402 static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
403 {
404 #ifdef REAL_DMA
405 	int dma_stat;
406 
407 	/* Turn off DMA and select sector counter register before
408 	 * accessing the status register (Atari recommendation!)
409 	 */
410 	st_dma.dma_mode_status = 0x90;
411 	dma_stat = st_dma.dma_mode_status;
412 
413 	/* Bit 0 indicates some error in the DMA process... don't know
414 	 * what happened exactly (no further docu).
415 	 */
416 	if (!(dma_stat & 0x01)) {
417 		/* DMA error */
418 		printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
419 	}
420 
421 	/* If the DMA was active, but now bit 1 is not clear, it is some
422 	 * other 5380 interrupt that finishes the DMA transfer. We have to
423 	 * calculate the number of residual bytes and give a warning if
424 	 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
425 	 */
426 	if (atari_dma_active && (dma_stat & 0x02)) {
427 		unsigned long transferred;
428 
429 		transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
430 		/* The ST-DMA address is incremented in 2-byte steps, but the
431 		 * data are written only in 16-byte chunks. If the number of
432 		 * transferred bytes is not divisible by 16, the remainder is
433 		 * lost somewhere in outer space.
434 		 */
435 		if (transferred & 15)
436 			printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
437 			       "ST-DMA fifo\n", transferred & 15);
438 
439 		atari_dma_residual = HOSTDATA_DMALEN - transferred;
440 		DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
441 			   atari_dma_residual);
442 	} else
443 		atari_dma_residual = 0;
444 	atari_dma_active = 0;
445 
446 	if (atari_dma_orig_addr) {
447 		/* If the dribble buffer was used on a read operation, copy the DMA-ed
448 		 * data to the original destination address.
449 		 */
450 		memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
451 		       HOSTDATA_DMALEN - atari_dma_residual);
452 		atari_dma_orig_addr = NULL;
453 	}
454 
455 #endif /* REAL_DMA */
456 
457 	NCR5380_intr(irq, dummy);
458 	return IRQ_HANDLED;
459 }
460 
461 
462 #ifdef REAL_DMA
463 static void atari_scsi_fetch_restbytes(void)
464 {
465 	int nr;
466 	char *src, *dst;
467 	unsigned long phys_dst;
468 
469 	/* fetch rest bytes in the DMA register */
470 	phys_dst = SCSI_DMA_READ_P(dma_addr);
471 	nr = phys_dst & 3;
472 	if (nr) {
473 		/* there are 'nr' bytes left for the last long address
474 		   before the DMA pointer */
475 		phys_dst ^= nr;
476 		DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
477 			   nr, phys_dst);
478 		/* The content of the DMA pointer is a physical address!  */
479 		dst = phys_to_virt(phys_dst);
480 		DMA_PRINTK(" = virt addr %p\n", dst);
481 		for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
482 			*dst++ = *src++;
483 	}
484 }
485 #endif /* REAL_DMA */
486 
487 
488 static int falcon_got_lock = 0;
489 static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait);
490 static int falcon_trying_lock = 0;
491 static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait);
492 static int falcon_dont_release = 0;
493 
494 /* This function releases the lock on the DMA chip if there is no
495  * connected command and the disconnected queue is empty. On
496  * releasing, instances of falcon_get_lock are awoken, that put
497  * themselves to sleep for fairness. They can now try to get the lock
498  * again (but others waiting longer more probably will win).
499  */
500 
501 static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
502 {
503 	unsigned long flags;
504 
505 	if (IS_A_TT())
506 		return;
507 
508 	local_irq_save(flags);
509 
510 	if (falcon_got_lock && !hostdata->disconnected_queue &&
511 	    !hostdata->issue_queue && !hostdata->connected) {
512 
513 		if (falcon_dont_release) {
514 #if 0
515 			printk("WARNING: Lock release not allowed. Ignored\n");
516 #endif
517 			local_irq_restore(flags);
518 			return;
519 		}
520 		falcon_got_lock = 0;
521 		stdma_release();
522 		wake_up(&falcon_fairness_wait);
523 	}
524 
525 	local_irq_restore(flags);
526 }
527 
528 /* This function manages the locking of the ST-DMA.
529  * If the DMA isn't locked already for SCSI, it tries to lock it by
530  * calling stdma_lock(). But if the DMA is locked by the SCSI code and
531  * there are other drivers waiting for the chip, we do not issue the
532  * command immediately but wait on 'falcon_fairness_queue'. We will be
533  * waked up when the DMA is unlocked by some SCSI interrupt. After that
534  * we try to get the lock again.
535  * But we must be prepared that more than one instance of
536  * falcon_get_lock() is waiting on the fairness queue. They should not
537  * try all at once to call stdma_lock(), one is enough! For that, the
538  * first one sets 'falcon_trying_lock', others that see that variable
539  * set wait on the queue 'falcon_try_wait'.
540  * Complicated, complicated.... Sigh...
541  */
542 
543 static void falcon_get_lock(void)
544 {
545 	unsigned long flags;
546 
547 	if (IS_A_TT())
548 		return;
549 
550 	local_irq_save(flags);
551 
552 	while (!in_irq() && falcon_got_lock && stdma_others_waiting())
553 		sleep_on(&falcon_fairness_wait);
554 
555 	while (!falcon_got_lock) {
556 		if (in_irq())
557 			panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
558 		if (!falcon_trying_lock) {
559 			falcon_trying_lock = 1;
560 			stdma_lock(scsi_falcon_intr, NULL);
561 			falcon_got_lock = 1;
562 			falcon_trying_lock = 0;
563 			wake_up(&falcon_try_wait);
564 		} else {
565 			sleep_on(&falcon_try_wait);
566 		}
567 	}
568 
569 	local_irq_restore(flags);
570 	if (!falcon_got_lock)
571 		panic("Falcon SCSI: someone stole the lock :-(\n");
572 }
573 
574 
575 int __init atari_scsi_detect(struct scsi_host_template *host)
576 {
577 	static int called = 0;
578 	struct Scsi_Host *instance;
579 
580 	if (!MACH_IS_ATARI ||
581 	    (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) ||
582 	    called)
583 		return 0;
584 
585 	host->proc_name = "Atari";
586 
587 	atari_scsi_reg_read  = IS_A_TT() ? atari_scsi_tt_reg_read :
588 					   atari_scsi_falcon_reg_read;
589 	atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write :
590 					   atari_scsi_falcon_reg_write;
591 
592 	/* setup variables */
593 	host->can_queue =
594 		(setup_can_queue > 0) ? setup_can_queue :
595 		IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE;
596 	host->cmd_per_lun =
597 		(setup_cmd_per_lun > 0) ? setup_cmd_per_lun :
598 		IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN;
599 	/* Force sg_tablesize to 0 on a Falcon! */
600 	host->sg_tablesize =
601 		!IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE :
602 		(setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE;
603 
604 	if (setup_hostid >= 0)
605 		host->this_id = setup_hostid;
606 	else {
607 		/* use 7 as default */
608 		host->this_id = 7;
609 		/* Test if a host id is set in the NVRam */
610 		if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
611 			unsigned char b = nvram_read_byte( 14 );
612 			/* Arbitration enabled? (for TOS) If yes, use configured host ID */
613 			if (b & 0x80)
614 				host->this_id = b & 7;
615 		}
616 	}
617 
618 #ifdef SUPPORT_TAGS
619 	if (setup_use_tagged_queuing < 0)
620 		setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING;
621 #endif
622 #ifdef REAL_DMA
623 	/* If running on a Falcon and if there's TT-Ram (i.e., more than one
624 	 * memory block, since there's always ST-Ram in a Falcon), then allocate a
625 	 * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative
626 	 * Ram.
627 	 */
628 	if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
629 	    !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
630 		atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
631 		if (!atari_dma_buffer) {
632 			printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM "
633 					"double buffer\n");
634 			return 0;
635 		}
636 		atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
637 		atari_dma_orig_addr = 0;
638 	}
639 #endif
640 	instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
641 	if (instance == NULL) {
642 		atari_stram_free(atari_dma_buffer);
643 		atari_dma_buffer = 0;
644 		return 0;
645 	}
646 	atari_scsi_host = instance;
647 	/*
648 	 * Set irq to 0, to avoid that the mid-level code disables our interrupt
649 	 * during queue_command calls. This is completely unnecessary, and even
650 	 * worse causes bad problems on the Falcon, where the int is shared with
651 	 * IDE and floppy!
652 	 */
653        instance->irq = 0;
654 
655 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
656 	atari_scsi_reset_boot();
657 #endif
658 	NCR5380_init(instance, 0);
659 
660 	if (IS_A_TT()) {
661 
662 		/* This int is actually "pseudo-slow", i.e. it acts like a slow
663 		 * interrupt after having cleared the pending flag for the DMA
664 		 * interrupt. */
665 		if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW,
666 				 "SCSI NCR5380", instance)) {
667 			printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI);
668 			scsi_unregister(atari_scsi_host);
669 			atari_stram_free(atari_dma_buffer);
670 			atari_dma_buffer = 0;
671 			return 0;
672 		}
673 		tt_mfp.active_edge |= 0x80;		/* SCSI int on L->H */
674 #ifdef REAL_DMA
675 		tt_scsi_dma.dma_ctrl = 0;
676 		atari_dma_residual = 0;
677 
678 		if (MACH_IS_MEDUSA) {
679 			/* While the read overruns (described by Drew Eckhardt in
680 			 * NCR5380.c) never happened on TTs, they do in fact on the Medusa
681 			 * (This was the cause why SCSI didn't work right for so long
682 			 * there.) Since handling the overruns slows down a bit, I turned
683 			 * the #ifdef's into a runtime condition.
684 			 *
685 			 * In principle it should be sufficient to do max. 1 byte with
686 			 * PIO, but there is another problem on the Medusa with the DMA
687 			 * rest data register. So 'atari_read_overruns' is currently set
688 			 * to 4 to avoid having transfers that aren't a multiple of 4. If
689 			 * the rest data bug is fixed, this can be lowered to 1.
690 			 */
691 			atari_read_overruns = 4;
692 		}
693 #endif /*REAL_DMA*/
694 	} else { /* ! IS_A_TT */
695 
696 		/* Nothing to do for the interrupt: the ST-DMA is initialized
697 		 * already by atari_init_INTS()
698 		 */
699 
700 #ifdef REAL_DMA
701 		atari_dma_residual = 0;
702 		atari_dma_active = 0;
703 		atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
704 					: 0xff000000);
705 #endif
706 	}
707 
708 	printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d "
709 #ifdef SUPPORT_TAGS
710 			"TAGGED-QUEUING=%s "
711 #endif
712 			"HOSTID=%d",
713 			instance->host_no, instance->hostt->can_queue,
714 			instance->hostt->cmd_per_lun,
715 			instance->hostt->sg_tablesize,
716 #ifdef SUPPORT_TAGS
717 			setup_use_tagged_queuing ? "yes" : "no",
718 #endif
719 			instance->hostt->this_id );
720 	NCR5380_print_options(instance);
721 	printk("\n");
722 
723 	called = 1;
724 	return 1;
725 }
726 
727 int atari_scsi_release(struct Scsi_Host *sh)
728 {
729 	if (IS_A_TT())
730 		free_irq(IRQ_TT_MFP_SCSI, sh);
731 	if (atari_dma_buffer)
732 		atari_stram_free(atari_dma_buffer);
733 	return 1;
734 }
735 
736 void __init atari_scsi_setup(char *str, int *ints)
737 {
738 	/* Format of atascsi parameter is:
739 	 *   atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
740 	 * Defaults depend on TT or Falcon, hostid determined at run time.
741 	 * Negative values mean don't change.
742 	 */
743 
744 	if (ints[0] < 1) {
745 		printk("atari_scsi_setup: no arguments!\n");
746 		return;
747 	}
748 
749 	if (ints[0] >= 1) {
750 		if (ints[1] > 0)
751 			/* no limits on this, just > 0 */
752 			setup_can_queue = ints[1];
753 	}
754 	if (ints[0] >= 2) {
755 		if (ints[2] > 0)
756 			setup_cmd_per_lun = ints[2];
757 	}
758 	if (ints[0] >= 3) {
759 		if (ints[3] >= 0) {
760 			setup_sg_tablesize = ints[3];
761 			/* Must be <= SG_ALL (255) */
762 			if (setup_sg_tablesize > SG_ALL)
763 				setup_sg_tablesize = SG_ALL;
764 		}
765 	}
766 	if (ints[0] >= 4) {
767 		/* Must be between 0 and 7 */
768 		if (ints[4] >= 0 && ints[4] <= 7)
769 			setup_hostid = ints[4];
770 		else if (ints[4] > 7)
771 			printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]);
772 	}
773 #ifdef SUPPORT_TAGS
774 	if (ints[0] >= 5) {
775 		if (ints[5] >= 0)
776 			setup_use_tagged_queuing = !!ints[5];
777 	}
778 #endif
779 }
780 
781 int atari_scsi_bus_reset(Scsi_Cmnd *cmd)
782 {
783 	int rv;
784 	struct NCR5380_hostdata *hostdata =
785 		(struct NCR5380_hostdata *)cmd->device->host->hostdata;
786 
787 	/* For doing the reset, SCSI interrupts must be disabled first,
788 	 * since the 5380 raises its IRQ line while _RST is active and we
789 	 * can't disable interrupts completely, since we need the timer.
790 	 */
791 	/* And abort a maybe active DMA transfer */
792 	if (IS_A_TT()) {
793 		atari_turnoff_irq(IRQ_TT_MFP_SCSI);
794 #ifdef REAL_DMA
795 		tt_scsi_dma.dma_ctrl = 0;
796 #endif /* REAL_DMA */
797 	} else {
798 		atari_turnoff_irq(IRQ_MFP_FSCSI);
799 #ifdef REAL_DMA
800 		st_dma.dma_mode_status = 0x90;
801 		atari_dma_active = 0;
802 		atari_dma_orig_addr = NULL;
803 #endif /* REAL_DMA */
804 	}
805 
806 	rv = NCR5380_bus_reset(cmd);
807 
808 	/* Re-enable ints */
809 	if (IS_A_TT()) {
810 		atari_turnon_irq(IRQ_TT_MFP_SCSI);
811 	} else {
812 		atari_turnon_irq(IRQ_MFP_FSCSI);
813 	}
814 	if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS)
815 		falcon_release_lock_if_possible(hostdata);
816 
817 	return rv;
818 }
819 
820 
821 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
822 static void __init atari_scsi_reset_boot(void)
823 {
824 	unsigned long end;
825 
826 	/*
827 	 * Do a SCSI reset to clean up the bus during initialization. No messing
828 	 * with the queues, interrupts, or locks necessary here.
829 	 */
830 
831 	printk("Atari SCSI: resetting the SCSI bus...");
832 
833 	/* get in phase */
834 	NCR5380_write(TARGET_COMMAND_REG,
835 		      PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
836 
837 	/* assert RST */
838 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
839 	/* The min. reset hold time is 25us, so 40us should be enough */
840 	udelay(50);
841 	/* reset RST and interrupt */
842 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
843 	NCR5380_read(RESET_PARITY_INTERRUPT_REG);
844 
845 	end = jiffies + AFTER_RESET_DELAY;
846 	while (time_before(jiffies, end))
847 		barrier();
848 
849 	printk(" done\n");
850 }
851 #endif
852 
853 
854 const char *atari_scsi_info(struct Scsi_Host *host)
855 {
856 	/* atari_scsi_detect() is verbose enough... */
857 	static const char string[] = "Atari native SCSI";
858 	return string;
859 }
860 
861 
862 #if defined(REAL_DMA)
863 
864 unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance, void *data,
865 				   unsigned long count, int dir)
866 {
867 	unsigned long addr = virt_to_phys(data);
868 
869 	DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
870 		   "dir = %d\n", instance->host_no, data, addr, count, dir);
871 
872 	if (!IS_A_TT() && !STRAM_ADDR(addr)) {
873 		/* If we have a non-DMAable address on a Falcon, use the dribble
874 		 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
875 		 * handler to copy data from the dribble buffer to the originally
876 		 * wanted address.
877 		 */
878 		if (dir)
879 			memcpy(atari_dma_buffer, data, count);
880 		else
881 			atari_dma_orig_addr = data;
882 		addr = atari_dma_phys_buffer;
883 	}
884 
885 	atari_dma_startaddr = addr;	/* Needed for calculating residual later. */
886 
887 	/* Cache cleanup stuff: On writes, push any dirty cache out before sending
888 	 * it to the peripheral. (Must be done before DMA setup, since at least
889 	 * the ST-DMA begins to fill internal buffers right after setup. For
890 	 * reads, invalidate any cache, may be altered after DMA without CPU
891 	 * knowledge.
892 	 *
893 	 * ++roman: For the Medusa, there's no need at all for that cache stuff,
894 	 * because the hardware does bus snooping (fine!).
895 	 */
896 	dma_cache_maintenance(addr, count, dir);
897 
898 	if (count == 0)
899 		printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
900 
901 	if (IS_A_TT()) {
902 		tt_scsi_dma.dma_ctrl = dir;
903 		SCSI_DMA_WRITE_P(dma_addr, addr);
904 		SCSI_DMA_WRITE_P(dma_cnt, count);
905 		tt_scsi_dma.dma_ctrl = dir | 2;
906 	} else { /* ! IS_A_TT */
907 
908 		/* set address */
909 		SCSI_DMA_SETADR(addr);
910 
911 		/* toggle direction bit to clear FIFO and set DMA direction */
912 		dir <<= 8;
913 		st_dma.dma_mode_status = 0x90 | dir;
914 		st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
915 		st_dma.dma_mode_status = 0x90 | dir;
916 		udelay(40);
917 		/* On writes, round up the transfer length to the next multiple of 512
918 		 * (see also comment at atari_dma_xfer_len()). */
919 		st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
920 		udelay(40);
921 		st_dma.dma_mode_status = 0x10 | dir;
922 		udelay(40);
923 		/* need not restore value of dir, only boolean value is tested */
924 		atari_dma_active = 1;
925 	}
926 
927 	return count;
928 }
929 
930 
931 static long atari_scsi_dma_residual(struct Scsi_Host *instance)
932 {
933 	return atari_dma_residual;
934 }
935 
936 
937 #define	CMD_SURELY_BLOCK_MODE	0
938 #define	CMD_SURELY_BYTE_MODE	1
939 #define	CMD_MODE_UNKNOWN		2
940 
941 static int falcon_classify_cmd(Scsi_Cmnd *cmd)
942 {
943 	unsigned char opcode = cmd->cmnd[0];
944 
945 	if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
946 	    opcode == READ_BUFFER)
947 		return CMD_SURELY_BYTE_MODE;
948 	else if (opcode == READ_6 || opcode == READ_10 ||
949 		 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
950 		 opcode == RECOVER_BUFFERED_DATA) {
951 		/* In case of a sequential-access target (tape), special care is
952 		 * needed here: The transfer is block-mode only if the 'fixed' bit is
953 		 * set! */
954 		if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
955 			return CMD_SURELY_BYTE_MODE;
956 		else
957 			return CMD_SURELY_BLOCK_MODE;
958 	} else
959 		return CMD_MODE_UNKNOWN;
960 }
961 
962 
963 /* This function calculates the number of bytes that can be transferred via
964  * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
965  * ST-DMA chip. There are only multiples of 512 bytes possible and max.
966  * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
967  * possible on the Falcon, since that would require to program the DMA for
968  * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
969  * the overrun problem, so this question is academic :-)
970  */
971 
972 static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
973 					Scsi_Cmnd *cmd, int write_flag)
974 {
975 	unsigned long	possible_len, limit;
976 
977 	if (IS_A_TT())
978 		/* TT SCSI DMA can transfer arbitrary #bytes */
979 		return wanted_len;
980 
981 	/* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
982 	 * 255*512 bytes, but this should be enough)
983 	 *
984 	 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
985 	 * that return a number of bytes which cannot be known beforehand. In this
986 	 * case, the given transfer length is an "allocation length". Now it
987 	 * can happen that this allocation length is a multiple of 512 bytes and
988 	 * the DMA is used. But if not n*512 bytes really arrive, some input data
989 	 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
990 	 * between commands that do block transfers and those that do byte
991 	 * transfers. But this isn't easy... there are lots of vendor specific
992 	 * commands, and the user can issue any command via the
993 	 * SCSI_IOCTL_SEND_COMMAND.
994 	 *
995 	 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
996 	 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
997 	 * and 3), the thing to do is obvious: allow any number of blocks via DMA
998 	 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
999 	 * the transfer (allocation) length is < 1024, hoping that no cmd. not
1000 	 * explicitly known as byte mode have such big allocation lengths...
1001 	 * BTW, all the discussion above applies only to reads. DMA writes are
1002 	 * unproblematic anyways, since the targets aborts the transfer after
1003 	 * receiving a sufficient number of bytes.
1004 	 *
1005 	 * Another point: If the transfer is from/to an non-ST-RAM address, we
1006 	 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
1007 	 */
1008 
1009 	if (write_flag) {
1010 		/* Write operation can always use the DMA, but the transfer size must
1011 		 * be rounded up to the next multiple of 512 (atari_dma_setup() does
1012 		 * this).
1013 		 */
1014 		possible_len = wanted_len;
1015 	} else {
1016 		/* Read operations: if the wanted transfer length is not a multiple of
1017 		 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
1018 		 * (no interrupt on DMA finished!)
1019 		 */
1020 		if (wanted_len & 0x1ff)
1021 			possible_len = 0;
1022 		else {
1023 			/* Now classify the command (see above) and decide whether it is
1024 			 * allowed to do DMA at all */
1025 			switch (falcon_classify_cmd(cmd)) {
1026 			case CMD_SURELY_BLOCK_MODE:
1027 				possible_len = wanted_len;
1028 				break;
1029 			case CMD_SURELY_BYTE_MODE:
1030 				possible_len = 0; /* DMA prohibited */
1031 				break;
1032 			case CMD_MODE_UNKNOWN:
1033 			default:
1034 				/* For unknown commands assume block transfers if the transfer
1035 				 * size/allocation length is >= 1024 */
1036 				possible_len = (wanted_len < 1024) ? 0 : wanted_len;
1037 				break;
1038 			}
1039 		}
1040 	}
1041 
1042 	/* Last step: apply the hard limit on DMA transfers */
1043 	limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
1044 		    STRAM_BUFFER_SIZE : 255*512;
1045 	if (possible_len > limit)
1046 		possible_len = limit;
1047 
1048 	if (possible_len != wanted_len)
1049 		DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes "
1050 			   "instead of %ld\n", possible_len, wanted_len);
1051 
1052 	return possible_len;
1053 }
1054 
1055 
1056 #endif	/* REAL_DMA */
1057 
1058 
1059 /* NCR5380 register access functions
1060  *
1061  * There are separate functions for TT and Falcon, because the access
1062  * methods are quite different. The calling macros NCR5380_read and
1063  * NCR5380_write call these functions via function pointers.
1064  */
1065 
1066 static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
1067 {
1068 	return tt_scsi_regp[reg * 2];
1069 }
1070 
1071 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
1072 {
1073 	tt_scsi_regp[reg * 2] = value;
1074 }
1075 
1076 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
1077 {
1078 	dma_wd.dma_mode_status= (u_short)(0x88 + reg);
1079 	return (u_char)dma_wd.fdc_acces_seccount;
1080 }
1081 
1082 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
1083 {
1084 	dma_wd.dma_mode_status = (u_short)(0x88 + reg);
1085 	dma_wd.fdc_acces_seccount = (u_short)value;
1086 }
1087 
1088 
1089 #include "atari_NCR5380.c"
1090 
1091 static struct scsi_host_template driver_template = {
1092 	.proc_info		= atari_scsi_proc_info,
1093 	.name			= "Atari native SCSI",
1094 	.detect			= atari_scsi_detect,
1095 	.release		= atari_scsi_release,
1096 	.info			= atari_scsi_info,
1097 	.queuecommand		= atari_scsi_queue_command,
1098 	.eh_abort_handler	= atari_scsi_abort,
1099 	.eh_bus_reset_handler	= atari_scsi_bus_reset,
1100 	.can_queue		= 0, /* initialized at run-time */
1101 	.this_id		= 0, /* initialized at run-time */
1102 	.sg_tablesize		= 0, /* initialized at run-time */
1103 	.cmd_per_lun		= 0, /* initialized at run-time */
1104 	.use_clustering		= DISABLE_CLUSTERING
1105 };
1106 
1107 
1108 #include "scsi_module.c"
1109 
1110 MODULE_LICENSE("GPL");
1111