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 * Notes for Falcon SCSI DMA
19 *
20 * The 5380 device is one of several that all share the DMA chip. Hence
21 * "locking" and "unlocking" access to this chip is required.
22 *
23 * Two possible schemes for ST DMA acquisition by atari_scsi are:
24 * 1) The lock is taken for each command separately (i.e. can_queue == 1).
25 * 2) The lock is taken when the first command arrives and released
26 * when the last command is finished (i.e. can_queue > 1).
27 *
28 * The first alternative limits SCSI bus utilization, since interleaving
29 * commands is not possible. The second gives better performance but is
30 * unfair to other drivers needing to use the ST DMA chip. In order to
31 * allow the IDE and floppy drivers equal access to the ST DMA chip
32 * the default is can_queue == 1.
33 */
34
35 #include <linux/module.h>
36 #include <linux/types.h>
37 #include <linux/blkdev.h>
38 #include <linux/interrupt.h>
39 #include <linux/init.h>
40 #include <linux/nvram.h>
41 #include <linux/bitops.h>
42 #include <linux/wait.h>
43 #include <linux/platform_device.h>
44
45 #include <asm/setup.h>
46 #include <asm/atarihw.h>
47 #include <asm/atariints.h>
48 #include <asm/atari_stdma.h>
49 #include <asm/atari_stram.h>
50 #include <asm/io.h>
51
52 #include <scsi/scsi_host.h>
53
54 #define DMA_MIN_SIZE 32
55
56 /* Definitions for the core NCR5380 driver. */
57
58 #define NCR5380_implementation_fields /* none */
59
60 static u8 (*atari_scsi_reg_read)(unsigned int);
61 static void (*atari_scsi_reg_write)(unsigned int, u8);
62
63 #define NCR5380_read(reg) atari_scsi_reg_read(reg)
64 #define NCR5380_write(reg, value) atari_scsi_reg_write(reg, value)
65
66 #define NCR5380_queue_command atari_scsi_queue_command
67 #define NCR5380_abort atari_scsi_abort
68 #define NCR5380_info atari_scsi_info
69
70 #define NCR5380_dma_xfer_len atari_scsi_dma_xfer_len
71 #define NCR5380_dma_recv_setup atari_scsi_dma_recv_setup
72 #define NCR5380_dma_send_setup atari_scsi_dma_send_setup
73 #define NCR5380_dma_residual atari_scsi_dma_residual
74
75 #define NCR5380_acquire_dma_irq(instance) falcon_get_lock(instance)
76 #define NCR5380_release_dma_irq(instance) falcon_release_lock()
77
78 #include "NCR5380.h"
79
80
81 #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI)
82
83 #define SCSI_DMA_WRITE_P(elt,val) \
84 do { \
85 unsigned long v = val; \
86 tt_scsi_dma.elt##_lo = v & 0xff; \
87 v >>= 8; \
88 tt_scsi_dma.elt##_lmd = v & 0xff; \
89 v >>= 8; \
90 tt_scsi_dma.elt##_hmd = v & 0xff; \
91 v >>= 8; \
92 tt_scsi_dma.elt##_hi = v & 0xff; \
93 } while(0)
94
95 #define SCSI_DMA_READ_P(elt) \
96 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \
97 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \
98 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \
99 (unsigned long)tt_scsi_dma.elt##_lo)
100
101
102 static inline void SCSI_DMA_SETADR(unsigned long adr)
103 {
104 st_dma.dma_lo = (unsigned char)adr;
105 MFPDELAY();
106 adr >>= 8;
107 st_dma.dma_md = (unsigned char)adr;
108 MFPDELAY();
109 adr >>= 8;
110 st_dma.dma_hi = (unsigned char)adr;
111 MFPDELAY();
112 }
113
114 static inline unsigned long SCSI_DMA_GETADR(void)
115 {
116 unsigned long adr;
117 adr = st_dma.dma_lo;
118 MFPDELAY();
119 adr |= (st_dma.dma_md & 0xff) << 8;
120 MFPDELAY();
121 adr |= (st_dma.dma_hi & 0xff) << 16;
122 MFPDELAY();
123 return adr;
124 }
125
126 static void atari_scsi_fetch_restbytes(void);
127
128 static unsigned long atari_dma_residual, atari_dma_startaddr;
129 static short atari_dma_active;
130 /* pointer to the dribble buffer */
131 static char *atari_dma_buffer;
132 /* precalculated physical address of the dribble buffer */
133 static unsigned long atari_dma_phys_buffer;
134 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */
135 static char *atari_dma_orig_addr;
136 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
137 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
138 * cases where requests to physical contiguous buffers have been merged, this
139 * request is <= 4k (one page). So I don't think we have to split transfers
140 * just due to this buffer size...
141 */
142 #define STRAM_BUFFER_SIZE (4096)
143 /* mask for address bits that can't be used with the ST-DMA */
144 static unsigned long atari_dma_stram_mask;
145 #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
146
147 static int setup_can_queue = -1;
148 module_param(setup_can_queue, int, 0);
149 static int setup_cmd_per_lun = -1;
150 module_param(setup_cmd_per_lun, int, 0);
151 static int setup_sg_tablesize = -1;
152 module_param(setup_sg_tablesize, int, 0);
153 static int setup_hostid = -1;
154 module_param(setup_hostid, int, 0);
155 static int setup_toshiba_delay = -1;
156 module_param(setup_toshiba_delay, int, 0);
157
158
159 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
160 {
161 int i;
162 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
163
164 if (dma_stat & 0x01) {
165
166 /* A bus error happens when DMA-ing from the last page of a
167 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
168 * Check for this case:
169 */
170
171 for (i = 0; i < m68k_num_memory; ++i) {
172 end_addr = m68k_memory[i].addr + m68k_memory[i].size;
173 if (end_addr <= addr && addr <= end_addr + 4)
174 return 1;
175 }
176 }
177 return 0;
178 }
179
180
181 static irqreturn_t scsi_tt_intr(int irq, void *dev)
182 {
183 struct Scsi_Host *instance = dev;
184 struct NCR5380_hostdata *hostdata = shost_priv(instance);
185 int dma_stat;
186
187 dma_stat = tt_scsi_dma.dma_ctrl;
188
189 dsprintk(NDEBUG_INTR, instance, "NCR5380 interrupt, DMA status = %02x\n",
190 dma_stat & 0xff);
191
192 /* Look if it was the DMA that has interrupted: First possibility
193 * is that a bus error occurred...
194 */
195 if (dma_stat & 0x80) {
196 if (!scsi_dma_is_ignored_buserr(dma_stat)) {
197 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
198 SCSI_DMA_READ_P(dma_addr));
199 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
200 }
201 }
202
203 /* If the DMA is active but not finished, we have the case
204 * that some other 5380 interrupt occurred within the DMA transfer.
205 * This means we have residual bytes, if the desired end address
206 * is not yet reached. Maybe we have to fetch some bytes from the
207 * rest data register, too. The residual must be calculated from
208 * the address pointer, not the counter register, because only the
209 * addr reg counts bytes not yet written and pending in the rest
210 * data reg!
211 */
212 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
213 atari_dma_residual = hostdata->dma_len -
214 (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
215
216 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
217 atari_dma_residual);
218
219 if ((signed int)atari_dma_residual < 0)
220 atari_dma_residual = 0;
221 if ((dma_stat & 1) == 0) {
222 /*
223 * After read operations, we maybe have to
224 * transport some rest bytes
225 */
226 atari_scsi_fetch_restbytes();
227 } else {
228 /*
229 * There seems to be a nasty bug in some SCSI-DMA/NCR
230 * combinations: If a target disconnects while a write
231 * operation is going on, the address register of the
232 * DMA may be a few bytes farer than it actually read.
233 * This is probably due to DMA prefetching and a delay
234 * between DMA and NCR. Experiments showed that the
235 * dma_addr is 9 bytes to high, but this could vary.
236 * The problem is, that the residual is thus calculated
237 * wrong and the next transfer will start behind where
238 * it should. So we round up the residual to the next
239 * multiple of a sector size, if it isn't already a
240 * multiple and the originally expected transfer size
241 * was. The latter condition is there to ensure that
242 * the correction is taken only for "real" data
243 * transfers and not for, e.g., the parameters of some
244 * other command. These shouldn't disconnect anyway.
245 */
246 if (atari_dma_residual & 0x1ff) {
247 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, "
248 "difference %ld bytes\n",
249 512 - (atari_dma_residual & 0x1ff));
250 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
251 }
252 }
253 tt_scsi_dma.dma_ctrl = 0;
254 }
255
256 /* If the DMA is finished, fetch the rest bytes and turn it off */
257 if (dma_stat & 0x40) {
258 atari_dma_residual = 0;
259 if ((dma_stat & 1) == 0)
260 atari_scsi_fetch_restbytes();
261 tt_scsi_dma.dma_ctrl = 0;
262 }
263
264 NCR5380_intr(irq, dev);
265
266 return IRQ_HANDLED;
267 }
268
269
270 static irqreturn_t scsi_falcon_intr(int irq, void *dev)
271 {
272 struct Scsi_Host *instance = dev;
273 struct NCR5380_hostdata *hostdata = shost_priv(instance);
274 int dma_stat;
275
276 /* Turn off DMA and select sector counter register before
277 * accessing the status register (Atari recommendation!)
278 */
279 st_dma.dma_mode_status = 0x90;
280 dma_stat = st_dma.dma_mode_status;
281
282 /* Bit 0 indicates some error in the DMA process... don't know
283 * what happened exactly (no further docu).
284 */
285 if (!(dma_stat & 0x01)) {
286 /* DMA error */
287 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
288 }
289
290 /* If the DMA was active, but now bit 1 is not clear, it is some
291 * other 5380 interrupt that finishes the DMA transfer. We have to
292 * calculate the number of residual bytes and give a warning if
293 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
294 */
295 if (atari_dma_active && (dma_stat & 0x02)) {
296 unsigned long transferred;
297
298 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
299 /* The ST-DMA address is incremented in 2-byte steps, but the
300 * data are written only in 16-byte chunks. If the number of
301 * transferred bytes is not divisible by 16, the remainder is
302 * lost somewhere in outer space.
303 */
304 if (transferred & 15)
305 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
306 "ST-DMA fifo\n", transferred & 15);
307
308 atari_dma_residual = hostdata->dma_len - transferred;
309 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
310 atari_dma_residual);
311 } else
312 atari_dma_residual = 0;
313 atari_dma_active = 0;
314
315 if (atari_dma_orig_addr) {
316 /* If the dribble buffer was used on a read operation, copy the DMA-ed
317 * data to the original destination address.
318 */
319 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
320 hostdata->dma_len - atari_dma_residual);
321 atari_dma_orig_addr = NULL;
322 }
323
324 NCR5380_intr(irq, dev);
325
326 return IRQ_HANDLED;
327 }
328
329
330 static void atari_scsi_fetch_restbytes(void)
331 {
332 int nr;
333 char *src, *dst;
334 unsigned long phys_dst;
335
336 /* fetch rest bytes in the DMA register */
337 phys_dst = SCSI_DMA_READ_P(dma_addr);
338 nr = phys_dst & 3;
339 if (nr) {
340 /* there are 'nr' bytes left for the last long address
341 before the DMA pointer */
342 phys_dst ^= nr;
343 dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
344 nr, phys_dst);
345 /* The content of the DMA pointer is a physical address! */
346 dst = phys_to_virt(phys_dst);
347 dprintk(NDEBUG_DMA, " = virt addr %p\n", dst);
348 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
349 *dst++ = *src++;
350 }
351 }
352
353
354 /* This function releases the lock on the DMA chip if there is no
355 * connected command and the disconnected queue is empty.
356 */
357
358 static void falcon_release_lock(void)
359 {
360 if (IS_A_TT())
361 return;
362
363 if (stdma_is_locked_by(scsi_falcon_intr))
364 stdma_release();
365 }
366
367 /* This function manages the locking of the ST-DMA.
368 * If the DMA isn't locked already for SCSI, it tries to lock it by
369 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
370 * there are other drivers waiting for the chip, we do not issue the
371 * command immediately but tell the SCSI mid-layer to defer.
372 */
373
374 static int falcon_get_lock(struct Scsi_Host *instance)
375 {
376 if (IS_A_TT())
377 return 1;
378
379 if (stdma_is_locked_by(scsi_falcon_intr) &&
380 instance->hostt->can_queue > 1)
381 return 1;
382
383 if (in_interrupt())
384 return stdma_try_lock(scsi_falcon_intr, instance);
385
386 stdma_lock(scsi_falcon_intr, instance);
387 return 1;
388 }
389
390 #ifndef MODULE
391 static int __init atari_scsi_setup(char *str)
392 {
393 /* Format of atascsi parameter is:
394 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
395 * Defaults depend on TT or Falcon, determined at run time.
396 * Negative values mean don't change.
397 */
398 int ints[8];
399
400 get_options(str, ARRAY_SIZE(ints), ints);
401
402 if (ints[0] < 1) {
403 printk("atari_scsi_setup: no arguments!\n");
404 return 0;
405 }
406 if (ints[0] >= 1)
407 setup_can_queue = ints[1];
408 if (ints[0] >= 2)
409 setup_cmd_per_lun = ints[2];
410 if (ints[0] >= 3)
411 setup_sg_tablesize = ints[3];
412 if (ints[0] >= 4)
413 setup_hostid = ints[4];
414 /* ints[5] (use_tagged_queuing) is ignored */
415 /* ints[6] (use_pdma) is ignored */
416 if (ints[0] >= 7)
417 setup_toshiba_delay = ints[7];
418
419 return 1;
420 }
421
422 __setup("atascsi=", atari_scsi_setup);
423 #endif /* !MODULE */
424
425 static unsigned long atari_scsi_dma_setup(struct NCR5380_hostdata *hostdata,
426 void *data, unsigned long count,
427 int dir)
428 {
429 unsigned long addr = virt_to_phys(data);
430
431 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, dir = %d\n",
432 hostdata->host->host_no, data, addr, count, dir);
433
434 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
435 /* If we have a non-DMAable address on a Falcon, use the dribble
436 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
437 * handler to copy data from the dribble buffer to the originally
438 * wanted address.
439 */
440 if (dir)
441 memcpy(atari_dma_buffer, data, count);
442 else
443 atari_dma_orig_addr = data;
444 addr = atari_dma_phys_buffer;
445 }
446
447 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
448
449 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
450 * it to the peripheral. (Must be done before DMA setup, since at least
451 * the ST-DMA begins to fill internal buffers right after setup. For
452 * reads, invalidate any cache, may be altered after DMA without CPU
453 * knowledge.
454 *
455 * ++roman: For the Medusa, there's no need at all for that cache stuff,
456 * because the hardware does bus snooping (fine!).
457 */
458 dma_cache_maintenance(addr, count, dir);
459
460 if (IS_A_TT()) {
461 tt_scsi_dma.dma_ctrl = dir;
462 SCSI_DMA_WRITE_P(dma_addr, addr);
463 SCSI_DMA_WRITE_P(dma_cnt, count);
464 tt_scsi_dma.dma_ctrl = dir | 2;
465 } else { /* ! IS_A_TT */
466
467 /* set address */
468 SCSI_DMA_SETADR(addr);
469
470 /* toggle direction bit to clear FIFO and set DMA direction */
471 dir <<= 8;
472 st_dma.dma_mode_status = 0x90 | dir;
473 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
474 st_dma.dma_mode_status = 0x90 | dir;
475 udelay(40);
476 /* On writes, round up the transfer length to the next multiple of 512
477 * (see also comment at atari_dma_xfer_len()). */
478 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
479 udelay(40);
480 st_dma.dma_mode_status = 0x10 | dir;
481 udelay(40);
482 /* need not restore value of dir, only boolean value is tested */
483 atari_dma_active = 1;
484 }
485
486 return count;
487 }
488
489 static inline int atari_scsi_dma_recv_setup(struct NCR5380_hostdata *hostdata,
490 unsigned char *data, int count)
491 {
492 return atari_scsi_dma_setup(hostdata, data, count, 0);
493 }
494
495 static inline int atari_scsi_dma_send_setup(struct NCR5380_hostdata *hostdata,
496 unsigned char *data, int count)
497 {
498 return atari_scsi_dma_setup(hostdata, data, count, 1);
499 }
500
501 static int atari_scsi_dma_residual(struct NCR5380_hostdata *hostdata)
502 {
503 return atari_dma_residual;
504 }
505
506
507 #define CMD_SURELY_BLOCK_MODE 0
508 #define CMD_SURELY_BYTE_MODE 1
509 #define CMD_MODE_UNKNOWN 2
510
511 static int falcon_classify_cmd(struct scsi_cmnd *cmd)
512 {
513 unsigned char opcode = cmd->cmnd[0];
514
515 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
516 opcode == READ_BUFFER)
517 return CMD_SURELY_BYTE_MODE;
518 else if (opcode == READ_6 || opcode == READ_10 ||
519 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
520 opcode == RECOVER_BUFFERED_DATA) {
521 /* In case of a sequential-access target (tape), special care is
522 * needed here: The transfer is block-mode only if the 'fixed' bit is
523 * set! */
524 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
525 return CMD_SURELY_BYTE_MODE;
526 else
527 return CMD_SURELY_BLOCK_MODE;
528 } else
529 return CMD_MODE_UNKNOWN;
530 }
531
532
533 /* This function calculates the number of bytes that can be transferred via
534 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
535 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
536 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
537 * possible on the Falcon, since that would require to program the DMA for
538 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
539 * the overrun problem, so this question is academic :-)
540 */
541
542 static int atari_scsi_dma_xfer_len(struct NCR5380_hostdata *hostdata,
543 struct scsi_cmnd *cmd)
544 {
545 int wanted_len = cmd->SCp.this_residual;
546 int possible_len, limit;
547
548 if (wanted_len < DMA_MIN_SIZE)
549 return 0;
550
551 if (IS_A_TT())
552 /* TT SCSI DMA can transfer arbitrary #bytes */
553 return wanted_len;
554
555 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
556 * 255*512 bytes, but this should be enough)
557 *
558 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
559 * that return a number of bytes which cannot be known beforehand. In this
560 * case, the given transfer length is an "allocation length". Now it
561 * can happen that this allocation length is a multiple of 512 bytes and
562 * the DMA is used. But if not n*512 bytes really arrive, some input data
563 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
564 * between commands that do block transfers and those that do byte
565 * transfers. But this isn't easy... there are lots of vendor specific
566 * commands, and the user can issue any command via the
567 * SCSI_IOCTL_SEND_COMMAND.
568 *
569 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
570 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
571 * and 3), the thing to do is obvious: allow any number of blocks via DMA
572 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
573 * the transfer (allocation) length is < 1024, hoping that no cmd. not
574 * explicitly known as byte mode have such big allocation lengths...
575 * BTW, all the discussion above applies only to reads. DMA writes are
576 * unproblematic anyways, since the targets aborts the transfer after
577 * receiving a sufficient number of bytes.
578 *
579 * Another point: If the transfer is from/to an non-ST-RAM address, we
580 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
581 */
582
583 if (cmd->sc_data_direction == DMA_TO_DEVICE) {
584 /* Write operation can always use the DMA, but the transfer size must
585 * be rounded up to the next multiple of 512 (atari_dma_setup() does
586 * this).
587 */
588 possible_len = wanted_len;
589 } else {
590 /* Read operations: if the wanted transfer length is not a multiple of
591 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
592 * (no interrupt on DMA finished!)
593 */
594 if (wanted_len & 0x1ff)
595 possible_len = 0;
596 else {
597 /* Now classify the command (see above) and decide whether it is
598 * allowed to do DMA at all */
599 switch (falcon_classify_cmd(cmd)) {
600 case CMD_SURELY_BLOCK_MODE:
601 possible_len = wanted_len;
602 break;
603 case CMD_SURELY_BYTE_MODE:
604 possible_len = 0; /* DMA prohibited */
605 break;
606 case CMD_MODE_UNKNOWN:
607 default:
608 /* For unknown commands assume block transfers if the transfer
609 * size/allocation length is >= 1024 */
610 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
611 break;
612 }
613 }
614 }
615
616 /* Last step: apply the hard limit on DMA transfers */
617 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
618 STRAM_BUFFER_SIZE : 255*512;
619 if (possible_len > limit)
620 possible_len = limit;
621
622 if (possible_len != wanted_len)
623 dprintk(NDEBUG_DMA, "DMA transfer now %d bytes instead of %d\n",
624 possible_len, wanted_len);
625
626 return possible_len;
627 }
628
629
630 /* NCR5380 register access functions
631 *
632 * There are separate functions for TT and Falcon, because the access
633 * methods are quite different. The calling macros NCR5380_read and
634 * NCR5380_write call these functions via function pointers.
635 */
636
637 static u8 atari_scsi_tt_reg_read(unsigned int reg)
638 {
639 return tt_scsi_regp[reg * 2];
640 }
641
642 static void atari_scsi_tt_reg_write(unsigned int reg, u8 value)
643 {
644 tt_scsi_regp[reg * 2] = value;
645 }
646
647 static u8 atari_scsi_falcon_reg_read(unsigned int reg)
648 {
649 unsigned long flags;
650 u8 result;
651
652 reg += 0x88;
653 local_irq_save(flags);
654 dma_wd.dma_mode_status = (u_short)reg;
655 result = (u8)dma_wd.fdc_acces_seccount;
656 local_irq_restore(flags);
657 return result;
658 }
659
660 static void atari_scsi_falcon_reg_write(unsigned int reg, u8 value)
661 {
662 unsigned long flags;
663
664 reg += 0x88;
665 local_irq_save(flags);
666 dma_wd.dma_mode_status = (u_short)reg;
667 dma_wd.fdc_acces_seccount = (u_short)value;
668 local_irq_restore(flags);
669 }
670
671
672 #include "NCR5380.c"
673
674 static int atari_scsi_host_reset(struct scsi_cmnd *cmd)
675 {
676 int rv;
677 unsigned long flags;
678
679 local_irq_save(flags);
680
681 /* Abort a maybe active DMA transfer */
682 if (IS_A_TT()) {
683 tt_scsi_dma.dma_ctrl = 0;
684 } else {
685 if (stdma_is_locked_by(scsi_falcon_intr))
686 st_dma.dma_mode_status = 0x90;
687 atari_dma_active = 0;
688 atari_dma_orig_addr = NULL;
689 }
690
691 rv = NCR5380_host_reset(cmd);
692
693 /* The 5380 raises its IRQ line while _RST is active but the ST DMA
694 * "lock" has been released so this interrupt may end up handled by
695 * floppy or IDE driver (if one of them holds the lock). The NCR5380
696 * interrupt flag has been cleared already.
697 */
698
699 local_irq_restore(flags);
700
701 return rv;
702 }
703
704 #define DRV_MODULE_NAME "atari_scsi"
705 #define PFX DRV_MODULE_NAME ": "
706
707 static struct scsi_host_template atari_scsi_template = {
708 .module = THIS_MODULE,
709 .proc_name = DRV_MODULE_NAME,
710 .name = "Atari native SCSI",
711 .info = atari_scsi_info,
712 .queuecommand = atari_scsi_queue_command,
713 .eh_abort_handler = atari_scsi_abort,
714 .eh_host_reset_handler = atari_scsi_host_reset,
715 .this_id = 7,
716 .cmd_per_lun = 2,
717 .dma_boundary = PAGE_SIZE - 1,
718 .cmd_size = NCR5380_CMD_SIZE,
719 };
720
721 static int __init atari_scsi_probe(struct platform_device *pdev)
722 {
723 struct Scsi_Host *instance;
724 int error;
725 struct resource *irq;
726 int host_flags = 0;
727
728 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
729 if (!irq)
730 return -ENODEV;
731
732 if (ATARIHW_PRESENT(TT_SCSI)) {
733 atari_scsi_reg_read = atari_scsi_tt_reg_read;
734 atari_scsi_reg_write = atari_scsi_tt_reg_write;
735 } else {
736 atari_scsi_reg_read = atari_scsi_falcon_reg_read;
737 atari_scsi_reg_write = atari_scsi_falcon_reg_write;
738 }
739
740 if (ATARIHW_PRESENT(TT_SCSI)) {
741 atari_scsi_template.can_queue = 16;
742 atari_scsi_template.sg_tablesize = SG_ALL;
743 } else {
744 atari_scsi_template.can_queue = 1;
745 atari_scsi_template.sg_tablesize = 1;
746 }
747
748 if (setup_can_queue > 0)
749 atari_scsi_template.can_queue = setup_can_queue;
750
751 if (setup_cmd_per_lun > 0)
752 atari_scsi_template.cmd_per_lun = setup_cmd_per_lun;
753
754 /* Don't increase sg_tablesize on Falcon! */
755 if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize > 0)
756 atari_scsi_template.sg_tablesize = setup_sg_tablesize;
757
758 if (setup_hostid >= 0) {
759 atari_scsi_template.this_id = setup_hostid & 7;
760 } else if (IS_REACHABLE(CONFIG_NVRAM)) {
761 /* Test if a host id is set in the NVRam */
762 if (ATARIHW_PRESENT(TT_CLK)) {
763 unsigned char b;
764 loff_t offset = 16;
765 ssize_t count = nvram_read(&b, 1, &offset);
766
767 /* Arbitration enabled? (for TOS)
768 * If yes, use configured host ID
769 */
770 if ((count == 1) && (b & 0x80))
771 atari_scsi_template.this_id = b & 7;
772 }
773 }
774
775 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
776 * memory block, since there's always ST-Ram in a Falcon), then
777 * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers
778 * from/to alternative Ram.
779 */
780 if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) &&
781 m68k_realnum_memory > 1) {
782 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
783 if (!atari_dma_buffer) {
784 pr_err(PFX "can't allocate ST-RAM double buffer\n");
785 return -ENOMEM;
786 }
787 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
788 atari_dma_orig_addr = NULL;
789 }
790
791 instance = scsi_host_alloc(&atari_scsi_template,
792 sizeof(struct NCR5380_hostdata));
793 if (!instance) {
794 error = -ENOMEM;
795 goto fail_alloc;
796 }
797
798 instance->irq = irq->start;
799
800 host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
801 host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
802
803 error = NCR5380_init(instance, host_flags);
804 if (error)
805 goto fail_init;
806
807 if (IS_A_TT()) {
808 error = request_irq(instance->irq, scsi_tt_intr, 0,
809 "NCR5380", instance);
810 if (error) {
811 pr_err(PFX "request irq %d failed, aborting\n",
812 instance->irq);
813 goto fail_irq;
814 }
815 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
816
817 tt_scsi_dma.dma_ctrl = 0;
818 atari_dma_residual = 0;
819
820 /* While the read overruns (described by Drew Eckhardt in
821 * NCR5380.c) never happened on TTs, they do in fact on the
822 * Medusa (This was the cause why SCSI didn't work right for
823 * so long there.) Since handling the overruns slows down
824 * a bit, I turned the #ifdef's into a runtime condition.
825 *
826 * In principle it should be sufficient to do max. 1 byte with
827 * PIO, but there is another problem on the Medusa with the DMA
828 * rest data register. So read_overruns is currently set
829 * to 4 to avoid having transfers that aren't a multiple of 4.
830 * If the rest data bug is fixed, this can be lowered to 1.
831 */
832 if (MACH_IS_MEDUSA) {
833 struct NCR5380_hostdata *hostdata =
834 shost_priv(instance);
835
836 hostdata->read_overruns = 4;
837 }
838 } else {
839 /* Nothing to do for the interrupt: the ST-DMA is initialized
840 * already.
841 */
842 atari_dma_residual = 0;
843 atari_dma_active = 0;
844 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
845 : 0xff000000);
846 }
847
848 NCR5380_maybe_reset_bus(instance);
849
850 error = scsi_add_host(instance, NULL);
851 if (error)
852 goto fail_host;
853
854 platform_set_drvdata(pdev, instance);
855
856 scsi_scan_host(instance);
857 return 0;
858
859 fail_host:
860 if (IS_A_TT())
861 free_irq(instance->irq, instance);
862 fail_irq:
863 NCR5380_exit(instance);
864 fail_init:
865 scsi_host_put(instance);
866 fail_alloc:
867 if (atari_dma_buffer)
868 atari_stram_free(atari_dma_buffer);
869 return error;
870 }
871
872 static int __exit atari_scsi_remove(struct platform_device *pdev)
873 {
874 struct Scsi_Host *instance = platform_get_drvdata(pdev);
875
876 scsi_remove_host(instance);
877 if (IS_A_TT())
878 free_irq(instance->irq, instance);
879 NCR5380_exit(instance);
880 scsi_host_put(instance);
881 if (atari_dma_buffer)
882 atari_stram_free(atari_dma_buffer);
883 return 0;
884 }
885
886 static struct platform_driver atari_scsi_driver = {
887 .remove = __exit_p(atari_scsi_remove),
888 .driver = {
889 .name = DRV_MODULE_NAME,
890 },
891 };
892
893 module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
894
895 MODULE_ALIAS("platform:" DRV_MODULE_NAME);
896 MODULE_LICENSE("GPL");