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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
60static u8 (*atari_scsi_reg_read)(unsigned int);
61static 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
102static 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
114static 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
126static void atari_scsi_fetch_restbytes(void);
127
128static unsigned long atari_dma_residual, atari_dma_startaddr;
129static short atari_dma_active;
130/* pointer to the dribble buffer */
131static char *atari_dma_buffer;
132/* precalculated physical address of the dribble buffer */
133static unsigned long atari_dma_phys_buffer;
134/* != 0 tells the Falcon int handler to copy data from the dribble buffer */
135static 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 */
144static unsigned long atari_dma_stram_mask;
145#define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
146
147static int setup_can_queue = -1;
148module_param(setup_can_queue, int, 0);
149static int setup_cmd_per_lun = -1;
150module_param(setup_cmd_per_lun, int, 0);
151static int setup_sg_tablesize = -1;
152module_param(setup_sg_tablesize, int, 0);
153static int setup_hostid = -1;
154module_param(setup_hostid, int, 0);
155static int setup_toshiba_delay = -1;
156module_param(setup_toshiba_delay, int, 0);
157
158
159static 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
181static 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
270static 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
330static 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
358static 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
374static 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 return 1;
381
382 /* stdma_lock() may sleep which means it can't be used here */
383 return stdma_try_lock(scsi_falcon_intr, instance);
384}
385
386#ifndef MODULE
387static int __init atari_scsi_setup(char *str)
388{
389 /* Format of atascsi parameter is:
390 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
391 * Defaults depend on TT or Falcon, determined at run time.
392 * Negative values mean don't change.
393 */
394 int ints[8];
395
396 get_options(str, ARRAY_SIZE(ints), ints);
397
398 if (ints[0] < 1) {
399 printk("atari_scsi_setup: no arguments!\n");
400 return 0;
401 }
402 if (ints[0] >= 1)
403 setup_can_queue = ints[1];
404 if (ints[0] >= 2)
405 setup_cmd_per_lun = ints[2];
406 if (ints[0] >= 3)
407 setup_sg_tablesize = ints[3];
408 if (ints[0] >= 4)
409 setup_hostid = ints[4];
410 /* ints[5] (use_tagged_queuing) is ignored */
411 /* ints[6] (use_pdma) is ignored */
412 if (ints[0] >= 7)
413 setup_toshiba_delay = ints[7];
414
415 return 1;
416}
417
418__setup("atascsi=", atari_scsi_setup);
419#endif /* !MODULE */
420
421static unsigned long atari_scsi_dma_setup(struct NCR5380_hostdata *hostdata,
422 void *data, unsigned long count,
423 int dir)
424{
425 unsigned long addr = virt_to_phys(data);
426
427 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, dir = %d\n",
428 hostdata->host->host_no, data, addr, count, dir);
429
430 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
431 /* If we have a non-DMAable address on a Falcon, use the dribble
432 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
433 * handler to copy data from the dribble buffer to the originally
434 * wanted address.
435 */
436 if (dir)
437 memcpy(atari_dma_buffer, data, count);
438 else
439 atari_dma_orig_addr = data;
440 addr = atari_dma_phys_buffer;
441 }
442
443 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
444
445 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
446 * it to the peripheral. (Must be done before DMA setup, since at least
447 * the ST-DMA begins to fill internal buffers right after setup. For
448 * reads, invalidate any cache, may be altered after DMA without CPU
449 * knowledge.
450 *
451 * ++roman: For the Medusa, there's no need at all for that cache stuff,
452 * because the hardware does bus snooping (fine!).
453 */
454 dma_cache_maintenance(addr, count, dir);
455
456 if (IS_A_TT()) {
457 tt_scsi_dma.dma_ctrl = dir;
458 SCSI_DMA_WRITE_P(dma_addr, addr);
459 SCSI_DMA_WRITE_P(dma_cnt, count);
460 tt_scsi_dma.dma_ctrl = dir | 2;
461 } else { /* ! IS_A_TT */
462
463 /* set address */
464 SCSI_DMA_SETADR(addr);
465
466 /* toggle direction bit to clear FIFO and set DMA direction */
467 dir <<= 8;
468 st_dma.dma_mode_status = 0x90 | dir;
469 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
470 st_dma.dma_mode_status = 0x90 | dir;
471 udelay(40);
472 /* On writes, round up the transfer length to the next multiple of 512
473 * (see also comment at atari_dma_xfer_len()). */
474 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
475 udelay(40);
476 st_dma.dma_mode_status = 0x10 | dir;
477 udelay(40);
478 /* need not restore value of dir, only boolean value is tested */
479 atari_dma_active = 1;
480 }
481
482 return count;
483}
484
485static inline int atari_scsi_dma_recv_setup(struct NCR5380_hostdata *hostdata,
486 unsigned char *data, int count)
487{
488 return atari_scsi_dma_setup(hostdata, data, count, 0);
489}
490
491static inline int atari_scsi_dma_send_setup(struct NCR5380_hostdata *hostdata,
492 unsigned char *data, int count)
493{
494 return atari_scsi_dma_setup(hostdata, data, count, 1);
495}
496
497static int atari_scsi_dma_residual(struct NCR5380_hostdata *hostdata)
498{
499 return atari_dma_residual;
500}
501
502
503#define CMD_SURELY_BLOCK_MODE 0
504#define CMD_SURELY_BYTE_MODE 1
505#define CMD_MODE_UNKNOWN 2
506
507static int falcon_classify_cmd(struct scsi_cmnd *cmd)
508{
509 unsigned char opcode = cmd->cmnd[0];
510
511 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
512 opcode == READ_BUFFER)
513 return CMD_SURELY_BYTE_MODE;
514 else if (opcode == READ_6 || opcode == READ_10 ||
515 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
516 opcode == RECOVER_BUFFERED_DATA) {
517 /* In case of a sequential-access target (tape), special care is
518 * needed here: The transfer is block-mode only if the 'fixed' bit is
519 * set! */
520 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
521 return CMD_SURELY_BYTE_MODE;
522 else
523 return CMD_SURELY_BLOCK_MODE;
524 } else
525 return CMD_MODE_UNKNOWN;
526}
527
528
529/* This function calculates the number of bytes that can be transferred via
530 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
531 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
532 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
533 * possible on the Falcon, since that would require to program the DMA for
534 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
535 * the overrun problem, so this question is academic :-)
536 */
537
538static int atari_scsi_dma_xfer_len(struct NCR5380_hostdata *hostdata,
539 struct scsi_cmnd *cmd)
540{
541 int wanted_len = NCR5380_to_ncmd(cmd)->this_residual;
542 int possible_len, limit;
543
544 if (wanted_len < DMA_MIN_SIZE)
545 return 0;
546
547 if (IS_A_TT())
548 /* TT SCSI DMA can transfer arbitrary #bytes */
549 return wanted_len;
550
551 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
552 * 255*512 bytes, but this should be enough)
553 *
554 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
555 * that return a number of bytes which cannot be known beforehand. In this
556 * case, the given transfer length is an "allocation length". Now it
557 * can happen that this allocation length is a multiple of 512 bytes and
558 * the DMA is used. But if not n*512 bytes really arrive, some input data
559 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
560 * between commands that do block transfers and those that do byte
561 * transfers. But this isn't easy... there are lots of vendor specific
562 * commands, and the user can issue any command via the
563 * SCSI_IOCTL_SEND_COMMAND.
564 *
565 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
566 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
567 * and 3), the thing to do is obvious: allow any number of blocks via DMA
568 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
569 * the transfer (allocation) length is < 1024, hoping that no cmd. not
570 * explicitly known as byte mode have such big allocation lengths...
571 * BTW, all the discussion above applies only to reads. DMA writes are
572 * unproblematic anyways, since the targets aborts the transfer after
573 * receiving a sufficient number of bytes.
574 *
575 * Another point: If the transfer is from/to an non-ST-RAM address, we
576 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
577 */
578
579 if (cmd->sc_data_direction == DMA_TO_DEVICE) {
580 /* Write operation can always use the DMA, but the transfer size must
581 * be rounded up to the next multiple of 512 (atari_dma_setup() does
582 * this).
583 */
584 possible_len = wanted_len;
585 } else {
586 /* Read operations: if the wanted transfer length is not a multiple of
587 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
588 * (no interrupt on DMA finished!)
589 */
590 if (wanted_len & 0x1ff)
591 possible_len = 0;
592 else {
593 /* Now classify the command (see above) and decide whether it is
594 * allowed to do DMA at all */
595 switch (falcon_classify_cmd(cmd)) {
596 case CMD_SURELY_BLOCK_MODE:
597 possible_len = wanted_len;
598 break;
599 case CMD_SURELY_BYTE_MODE:
600 possible_len = 0; /* DMA prohibited */
601 break;
602 case CMD_MODE_UNKNOWN:
603 default:
604 /* For unknown commands assume block transfers if the transfer
605 * size/allocation length is >= 1024 */
606 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
607 break;
608 }
609 }
610 }
611
612 /* Last step: apply the hard limit on DMA transfers */
613 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(NCR5380_to_ncmd(cmd)->ptr))) ?
614 STRAM_BUFFER_SIZE : 255*512;
615 if (possible_len > limit)
616 possible_len = limit;
617
618 if (possible_len != wanted_len)
619 dprintk(NDEBUG_DMA, "DMA transfer now %d bytes instead of %d\n",
620 possible_len, wanted_len);
621
622 return possible_len;
623}
624
625
626/* NCR5380 register access functions
627 *
628 * There are separate functions for TT and Falcon, because the access
629 * methods are quite different. The calling macros NCR5380_read and
630 * NCR5380_write call these functions via function pointers.
631 */
632
633static u8 atari_scsi_tt_reg_read(unsigned int reg)
634{
635 return tt_scsi_regp[reg * 2];
636}
637
638static void atari_scsi_tt_reg_write(unsigned int reg, u8 value)
639{
640 tt_scsi_regp[reg * 2] = value;
641}
642
643static u8 atari_scsi_falcon_reg_read(unsigned int reg)
644{
645 unsigned long flags;
646 u8 result;
647
648 reg += 0x88;
649 local_irq_save(flags);
650 dma_wd.dma_mode_status = (u_short)reg;
651 result = (u8)dma_wd.fdc_acces_seccount;
652 local_irq_restore(flags);
653 return result;
654}
655
656static void atari_scsi_falcon_reg_write(unsigned int reg, u8 value)
657{
658 unsigned long flags;
659
660 reg += 0x88;
661 local_irq_save(flags);
662 dma_wd.dma_mode_status = (u_short)reg;
663 dma_wd.fdc_acces_seccount = (u_short)value;
664 local_irq_restore(flags);
665}
666
667
668#include "NCR5380.c"
669
670static int atari_scsi_host_reset(struct scsi_cmnd *cmd)
671{
672 int rv;
673 unsigned long flags;
674
675 local_irq_save(flags);
676
677 /* Abort a maybe active DMA transfer */
678 if (IS_A_TT()) {
679 tt_scsi_dma.dma_ctrl = 0;
680 } else {
681 if (stdma_is_locked_by(scsi_falcon_intr))
682 st_dma.dma_mode_status = 0x90;
683 atari_dma_active = 0;
684 atari_dma_orig_addr = NULL;
685 }
686
687 rv = NCR5380_host_reset(cmd);
688
689 /* The 5380 raises its IRQ line while _RST is active but the ST DMA
690 * "lock" has been released so this interrupt may end up handled by
691 * floppy or IDE driver (if one of them holds the lock). The NCR5380
692 * interrupt flag has been cleared already.
693 */
694
695 local_irq_restore(flags);
696
697 return rv;
698}
699
700#define DRV_MODULE_NAME "atari_scsi"
701#define PFX DRV_MODULE_NAME ": "
702
703static struct scsi_host_template atari_scsi_template = {
704 .module = THIS_MODULE,
705 .proc_name = DRV_MODULE_NAME,
706 .name = "Atari native SCSI",
707 .info = atari_scsi_info,
708 .queuecommand = atari_scsi_queue_command,
709 .eh_abort_handler = atari_scsi_abort,
710 .eh_host_reset_handler = atari_scsi_host_reset,
711 .this_id = 7,
712 .cmd_per_lun = 2,
713 .dma_boundary = PAGE_SIZE - 1,
714 .cmd_size = sizeof(struct NCR5380_cmd),
715};
716
717static int __init atari_scsi_probe(struct platform_device *pdev)
718{
719 struct Scsi_Host *instance;
720 int error;
721 struct resource *irq;
722 int host_flags = 0;
723
724 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
725 if (!irq)
726 return -ENODEV;
727
728 if (ATARIHW_PRESENT(TT_SCSI)) {
729 atari_scsi_reg_read = atari_scsi_tt_reg_read;
730 atari_scsi_reg_write = atari_scsi_tt_reg_write;
731 } else {
732 atari_scsi_reg_read = atari_scsi_falcon_reg_read;
733 atari_scsi_reg_write = atari_scsi_falcon_reg_write;
734 }
735
736 if (ATARIHW_PRESENT(TT_SCSI)) {
737 atari_scsi_template.can_queue = 16;
738 atari_scsi_template.sg_tablesize = SG_ALL;
739 } else {
740 atari_scsi_template.can_queue = 1;
741 atari_scsi_template.sg_tablesize = 1;
742 }
743
744 if (setup_can_queue > 0)
745 atari_scsi_template.can_queue = setup_can_queue;
746
747 if (setup_cmd_per_lun > 0)
748 atari_scsi_template.cmd_per_lun = setup_cmd_per_lun;
749
750 /* Don't increase sg_tablesize on Falcon! */
751 if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize > 0)
752 atari_scsi_template.sg_tablesize = setup_sg_tablesize;
753
754 if (setup_hostid >= 0) {
755 atari_scsi_template.this_id = setup_hostid & 7;
756 } else if (IS_REACHABLE(CONFIG_NVRAM)) {
757 /* Test if a host id is set in the NVRam */
758 if (ATARIHW_PRESENT(TT_CLK)) {
759 unsigned char b;
760 loff_t offset = 16;
761 ssize_t count = nvram_read(&b, 1, &offset);
762
763 /* Arbitration enabled? (for TOS)
764 * If yes, use configured host ID
765 */
766 if ((count == 1) && (b & 0x80))
767 atari_scsi_template.this_id = b & 7;
768 }
769 }
770
771 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
772 * memory block, since there's always ST-Ram in a Falcon), then
773 * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers
774 * from/to alternative Ram.
775 */
776 if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) &&
777 m68k_realnum_memory > 1) {
778 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
779 if (!atari_dma_buffer) {
780 pr_err(PFX "can't allocate ST-RAM double buffer\n");
781 return -ENOMEM;
782 }
783 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
784 atari_dma_orig_addr = NULL;
785 }
786
787 instance = scsi_host_alloc(&atari_scsi_template,
788 sizeof(struct NCR5380_hostdata));
789 if (!instance) {
790 error = -ENOMEM;
791 goto fail_alloc;
792 }
793
794 instance->irq = irq->start;
795
796 host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
797 host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
798
799 error = NCR5380_init(instance, host_flags);
800 if (error)
801 goto fail_init;
802
803 if (IS_A_TT()) {
804 error = request_irq(instance->irq, scsi_tt_intr, 0,
805 "NCR5380", instance);
806 if (error) {
807 pr_err(PFX "request irq %d failed, aborting\n",
808 instance->irq);
809 goto fail_irq;
810 }
811 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
812
813 tt_scsi_dma.dma_ctrl = 0;
814 atari_dma_residual = 0;
815
816 /* While the read overruns (described by Drew Eckhardt in
817 * NCR5380.c) never happened on TTs, they do in fact on the
818 * Medusa (This was the cause why SCSI didn't work right for
819 * so long there.) Since handling the overruns slows down
820 * a bit, I turned the #ifdef's into a runtime condition.
821 *
822 * In principle it should be sufficient to do max. 1 byte with
823 * PIO, but there is another problem on the Medusa with the DMA
824 * rest data register. So read_overruns is currently set
825 * to 4 to avoid having transfers that aren't a multiple of 4.
826 * If the rest data bug is fixed, this can be lowered to 1.
827 */
828 if (MACH_IS_MEDUSA) {
829 struct NCR5380_hostdata *hostdata =
830 shost_priv(instance);
831
832 hostdata->read_overruns = 4;
833 }
834 } else {
835 /* Nothing to do for the interrupt: the ST-DMA is initialized
836 * already.
837 */
838 atari_dma_residual = 0;
839 atari_dma_active = 0;
840 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
841 : 0xff000000);
842 }
843
844 NCR5380_maybe_reset_bus(instance);
845
846 error = scsi_add_host(instance, NULL);
847 if (error)
848 goto fail_host;
849
850 platform_set_drvdata(pdev, instance);
851
852 scsi_scan_host(instance);
853 return 0;
854
855fail_host:
856 if (IS_A_TT())
857 free_irq(instance->irq, instance);
858fail_irq:
859 NCR5380_exit(instance);
860fail_init:
861 scsi_host_put(instance);
862fail_alloc:
863 if (atari_dma_buffer)
864 atari_stram_free(atari_dma_buffer);
865 return error;
866}
867
868static void __exit atari_scsi_remove(struct platform_device *pdev)
869{
870 struct Scsi_Host *instance = platform_get_drvdata(pdev);
871
872 scsi_remove_host(instance);
873 if (IS_A_TT())
874 free_irq(instance->irq, instance);
875 NCR5380_exit(instance);
876 scsi_host_put(instance);
877 if (atari_dma_buffer)
878 atari_stram_free(atari_dma_buffer);
879}
880
881static struct platform_driver atari_scsi_driver = {
882 .remove_new = __exit_p(atari_scsi_remove),
883 .driver = {
884 .name = DRV_MODULE_NAME,
885 },
886};
887
888module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
889
890MODULE_ALIAS("platform:" DRV_MODULE_NAME);
891MODULE_LICENSE("GPL");
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#include <linux/wait.h>
94
95#include <asm/setup.h>
96#include <asm/atarihw.h>
97#include <asm/atariints.h>
98#include <asm/page.h>
99#include <asm/pgtable.h>
100#include <asm/irq.h>
101#include <asm/traps.h>
102
103#include "scsi.h"
104#include <scsi/scsi_host.h>
105#include "atari_scsi.h"
106#include "NCR5380.h"
107#include <asm/atari_stdma.h>
108#include <asm/atari_stram.h>
109#include <asm/io.h>
110
111#include <linux/stat.h>
112
113#define IS_A_TT() ATARIHW_PRESENT(TT_SCSI)
114
115#define SCSI_DMA_WRITE_P(elt,val) \
116 do { \
117 unsigned long v = val; \
118 tt_scsi_dma.elt##_lo = v & 0xff; \
119 v >>= 8; \
120 tt_scsi_dma.elt##_lmd = v & 0xff; \
121 v >>= 8; \
122 tt_scsi_dma.elt##_hmd = v & 0xff; \
123 v >>= 8; \
124 tt_scsi_dma.elt##_hi = v & 0xff; \
125 } while(0)
126
127#define SCSI_DMA_READ_P(elt) \
128 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \
129 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \
130 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \
131 (unsigned long)tt_scsi_dma.elt##_lo)
132
133
134static inline void SCSI_DMA_SETADR(unsigned long adr)
135{
136 st_dma.dma_lo = (unsigned char)adr;
137 MFPDELAY();
138 adr >>= 8;
139 st_dma.dma_md = (unsigned char)adr;
140 MFPDELAY();
141 adr >>= 8;
142 st_dma.dma_hi = (unsigned char)adr;
143 MFPDELAY();
144}
145
146static inline unsigned long SCSI_DMA_GETADR(void)
147{
148 unsigned long adr;
149 adr = st_dma.dma_lo;
150 MFPDELAY();
151 adr |= (st_dma.dma_md & 0xff) << 8;
152 MFPDELAY();
153 adr |= (st_dma.dma_hi & 0xff) << 16;
154 MFPDELAY();
155 return adr;
156}
157
158static inline void ENABLE_IRQ(void)
159{
160 if (IS_A_TT())
161 atari_enable_irq(IRQ_TT_MFP_SCSI);
162 else
163 atari_enable_irq(IRQ_MFP_FSCSI);
164}
165
166static inline void DISABLE_IRQ(void)
167{
168 if (IS_A_TT())
169 atari_disable_irq(IRQ_TT_MFP_SCSI);
170 else
171 atari_disable_irq(IRQ_MFP_FSCSI);
172}
173
174
175#define HOSTDATA_DMALEN (((struct NCR5380_hostdata *) \
176 (atari_scsi_host->hostdata))->dma_len)
177
178/* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
179 * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
180 * need ten times the standard value... */
181#ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
182#define AFTER_RESET_DELAY (HZ/2)
183#else
184#define AFTER_RESET_DELAY (5*HZ/2)
185#endif
186
187/***************************** Prototypes *****************************/
188
189#ifdef REAL_DMA
190static int scsi_dma_is_ignored_buserr(unsigned char dma_stat);
191static void atari_scsi_fetch_restbytes(void);
192static long atari_scsi_dma_residual(struct Scsi_Host *instance);
193static int falcon_classify_cmd(Scsi_Cmnd *cmd);
194static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
195 Scsi_Cmnd *cmd, int write_flag);
196#endif
197static irqreturn_t scsi_tt_intr(int irq, void *dummy);
198static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
199static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
200static void falcon_get_lock(void);
201#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
202static void atari_scsi_reset_boot(void);
203#endif
204static unsigned char atari_scsi_tt_reg_read(unsigned char reg);
205static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value);
206static unsigned char atari_scsi_falcon_reg_read(unsigned char reg);
207static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value);
208
209/************************* End of Prototypes **************************/
210
211
212static struct Scsi_Host *atari_scsi_host;
213static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
214static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
215
216#ifdef REAL_DMA
217static unsigned long atari_dma_residual, atari_dma_startaddr;
218static short atari_dma_active;
219/* pointer to the dribble buffer */
220static char *atari_dma_buffer;
221/* precalculated physical address of the dribble buffer */
222static unsigned long atari_dma_phys_buffer;
223/* != 0 tells the Falcon int handler to copy data from the dribble buffer */
224static char *atari_dma_orig_addr;
225/* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
226 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
227 * cases where requests to physical contiguous buffers have been merged, this
228 * request is <= 4k (one page). So I don't think we have to split transfers
229 * just due to this buffer size...
230 */
231#define STRAM_BUFFER_SIZE (4096)
232/* mask for address bits that can't be used with the ST-DMA */
233static unsigned long atari_dma_stram_mask;
234#define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
235/* number of bytes to cut from a transfer to handle NCR overruns */
236static int atari_read_overruns;
237#endif
238
239static int setup_can_queue = -1;
240module_param(setup_can_queue, int, 0);
241static int setup_cmd_per_lun = -1;
242module_param(setup_cmd_per_lun, int, 0);
243static int setup_sg_tablesize = -1;
244module_param(setup_sg_tablesize, int, 0);
245#ifdef SUPPORT_TAGS
246static int setup_use_tagged_queuing = -1;
247module_param(setup_use_tagged_queuing, int, 0);
248#endif
249static int setup_hostid = -1;
250module_param(setup_hostid, int, 0);
251
252
253#if defined(REAL_DMA)
254
255static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
256{
257 int i;
258 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
259
260 if (dma_stat & 0x01) {
261
262 /* A bus error happens when DMA-ing from the last page of a
263 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
264 * Check for this case:
265 */
266
267 for (i = 0; i < m68k_num_memory; ++i) {
268 end_addr = m68k_memory[i].addr + m68k_memory[i].size;
269 if (end_addr <= addr && addr <= end_addr + 4)
270 return 1;
271 }
272 }
273 return 0;
274}
275
276
277#if 0
278/* Dead code... wasn't called anyway :-) and causes some trouble, because at
279 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
280 * to clear the DMA int pending bit before it allows other level 6 interrupts.
281 */
282static void scsi_dma_buserr(int irq, void *dummy)
283{
284 unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
285
286 /* Don't do anything if a NCR interrupt is pending. Probably it's just
287 * masked... */
288 if (atari_irq_pending(IRQ_TT_MFP_SCSI))
289 return;
290
291 printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
292 SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
293 if (dma_stat & 0x80) {
294 if (!scsi_dma_is_ignored_buserr(dma_stat))
295 printk("SCSI DMA bus error -- bad DMA programming!\n");
296 } else {
297 /* Under normal circumstances we never should get to this point,
298 * since both interrupts are triggered simultaneously and the 5380
299 * int has higher priority. When this irq is handled, that DMA
300 * interrupt is cleared. So a warning message is printed here.
301 */
302 printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
303 }
304}
305#endif
306
307#endif
308
309
310static irqreturn_t scsi_tt_intr(int irq, void *dummy)
311{
312#ifdef REAL_DMA
313 int dma_stat;
314
315 dma_stat = tt_scsi_dma.dma_ctrl;
316
317 INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n",
318 atari_scsi_host->host_no, dma_stat & 0xff);
319
320 /* Look if it was the DMA that has interrupted: First possibility
321 * is that a bus error occurred...
322 */
323 if (dma_stat & 0x80) {
324 if (!scsi_dma_is_ignored_buserr(dma_stat)) {
325 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
326 SCSI_DMA_READ_P(dma_addr));
327 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
328 }
329 }
330
331 /* If the DMA is active but not finished, we have the case
332 * that some other 5380 interrupt occurred within the DMA transfer.
333 * This means we have residual bytes, if the desired end address
334 * is not yet reached. Maybe we have to fetch some bytes from the
335 * rest data register, too. The residual must be calculated from
336 * the address pointer, not the counter register, because only the
337 * addr reg counts bytes not yet written and pending in the rest
338 * data reg!
339 */
340 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
341 atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
342
343 DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
344 atari_dma_residual);
345
346 if ((signed int)atari_dma_residual < 0)
347 atari_dma_residual = 0;
348 if ((dma_stat & 1) == 0) {
349 /*
350 * After read operations, we maybe have to
351 * transport some rest bytes
352 */
353 atari_scsi_fetch_restbytes();
354 } else {
355 /*
356 * There seems to be a nasty bug in some SCSI-DMA/NCR
357 * combinations: If a target disconnects while a write
358 * operation is going on, the address register of the
359 * DMA may be a few bytes farer than it actually read.
360 * This is probably due to DMA prefetching and a delay
361 * between DMA and NCR. Experiments showed that the
362 * dma_addr is 9 bytes to high, but this could vary.
363 * The problem is, that the residual is thus calculated
364 * wrong and the next transfer will start behind where
365 * it should. So we round up the residual to the next
366 * multiple of a sector size, if it isn't already a
367 * multiple and the originally expected transfer size
368 * was. The latter condition is there to ensure that
369 * the correction is taken only for "real" data
370 * transfers and not for, e.g., the parameters of some
371 * other command. These shouldn't disconnect anyway.
372 */
373 if (atari_dma_residual & 0x1ff) {
374 DMA_PRINTK("SCSI DMA: DMA bug corrected, "
375 "difference %ld bytes\n",
376 512 - (atari_dma_residual & 0x1ff));
377 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
378 }
379 }
380 tt_scsi_dma.dma_ctrl = 0;
381 }
382
383 /* If the DMA is finished, fetch the rest bytes and turn it off */
384 if (dma_stat & 0x40) {
385 atari_dma_residual = 0;
386 if ((dma_stat & 1) == 0)
387 atari_scsi_fetch_restbytes();
388 tt_scsi_dma.dma_ctrl = 0;
389 }
390
391#endif /* REAL_DMA */
392
393 NCR5380_intr(irq, dummy);
394
395#if 0
396 /* To be sure the int is not masked */
397 atari_enable_irq(IRQ_TT_MFP_SCSI);
398#endif
399 return IRQ_HANDLED;
400}
401
402
403static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
404{
405#ifdef REAL_DMA
406 int dma_stat;
407
408 /* Turn off DMA and select sector counter register before
409 * accessing the status register (Atari recommendation!)
410 */
411 st_dma.dma_mode_status = 0x90;
412 dma_stat = st_dma.dma_mode_status;
413
414 /* Bit 0 indicates some error in the DMA process... don't know
415 * what happened exactly (no further docu).
416 */
417 if (!(dma_stat & 0x01)) {
418 /* DMA error */
419 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
420 }
421
422 /* If the DMA was active, but now bit 1 is not clear, it is some
423 * other 5380 interrupt that finishes the DMA transfer. We have to
424 * calculate the number of residual bytes and give a warning if
425 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
426 */
427 if (atari_dma_active && (dma_stat & 0x02)) {
428 unsigned long transferred;
429
430 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
431 /* The ST-DMA address is incremented in 2-byte steps, but the
432 * data are written only in 16-byte chunks. If the number of
433 * transferred bytes is not divisible by 16, the remainder is
434 * lost somewhere in outer space.
435 */
436 if (transferred & 15)
437 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
438 "ST-DMA fifo\n", transferred & 15);
439
440 atari_dma_residual = HOSTDATA_DMALEN - transferred;
441 DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
442 atari_dma_residual);
443 } else
444 atari_dma_residual = 0;
445 atari_dma_active = 0;
446
447 if (atari_dma_orig_addr) {
448 /* If the dribble buffer was used on a read operation, copy the DMA-ed
449 * data to the original destination address.
450 */
451 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
452 HOSTDATA_DMALEN - atari_dma_residual);
453 atari_dma_orig_addr = NULL;
454 }
455
456#endif /* REAL_DMA */
457
458 NCR5380_intr(irq, dummy);
459 return IRQ_HANDLED;
460}
461
462
463#ifdef REAL_DMA
464static void atari_scsi_fetch_restbytes(void)
465{
466 int nr;
467 char *src, *dst;
468 unsigned long phys_dst;
469
470 /* fetch rest bytes in the DMA register */
471 phys_dst = SCSI_DMA_READ_P(dma_addr);
472 nr = phys_dst & 3;
473 if (nr) {
474 /* there are 'nr' bytes left for the last long address
475 before the DMA pointer */
476 phys_dst ^= nr;
477 DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
478 nr, phys_dst);
479 /* The content of the DMA pointer is a physical address! */
480 dst = phys_to_virt(phys_dst);
481 DMA_PRINTK(" = virt addr %p\n", dst);
482 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
483 *dst++ = *src++;
484 }
485}
486#endif /* REAL_DMA */
487
488
489static int falcon_got_lock = 0;
490static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait);
491static int falcon_trying_lock = 0;
492static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait);
493static int falcon_dont_release = 0;
494
495/* This function releases the lock on the DMA chip if there is no
496 * connected command and the disconnected queue is empty. On
497 * releasing, instances of falcon_get_lock are awoken, that put
498 * themselves to sleep for fairness. They can now try to get the lock
499 * again (but others waiting longer more probably will win).
500 */
501
502static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
503{
504 unsigned long flags;
505
506 if (IS_A_TT())
507 return;
508
509 local_irq_save(flags);
510
511 if (falcon_got_lock && !hostdata->disconnected_queue &&
512 !hostdata->issue_queue && !hostdata->connected) {
513
514 if (falcon_dont_release) {
515#if 0
516 printk("WARNING: Lock release not allowed. Ignored\n");
517#endif
518 local_irq_restore(flags);
519 return;
520 }
521 falcon_got_lock = 0;
522 stdma_release();
523 wake_up(&falcon_fairness_wait);
524 }
525
526 local_irq_restore(flags);
527}
528
529/* This function manages the locking of the ST-DMA.
530 * If the DMA isn't locked already for SCSI, it tries to lock it by
531 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
532 * there are other drivers waiting for the chip, we do not issue the
533 * command immediately but wait on 'falcon_fairness_queue'. We will be
534 * waked up when the DMA is unlocked by some SCSI interrupt. After that
535 * we try to get the lock again.
536 * But we must be prepared that more than one instance of
537 * falcon_get_lock() is waiting on the fairness queue. They should not
538 * try all at once to call stdma_lock(), one is enough! For that, the
539 * first one sets 'falcon_trying_lock', others that see that variable
540 * set wait on the queue 'falcon_try_wait'.
541 * Complicated, complicated.... Sigh...
542 */
543
544static void falcon_get_lock(void)
545{
546 unsigned long flags;
547
548 if (IS_A_TT())
549 return;
550
551 local_irq_save(flags);
552
553 wait_event_cmd(falcon_fairness_wait,
554 in_interrupt() || !falcon_got_lock || !stdma_others_waiting(),
555 local_irq_restore(flags),
556 local_irq_save(flags));
557
558 while (!falcon_got_lock) {
559 if (in_irq())
560 panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
561 if (!falcon_trying_lock) {
562 falcon_trying_lock = 1;
563 stdma_lock(scsi_falcon_intr, NULL);
564 falcon_got_lock = 1;
565 falcon_trying_lock = 0;
566 wake_up(&falcon_try_wait);
567 } else {
568 wait_event_cmd(falcon_try_wait,
569 falcon_got_lock && !falcon_trying_lock,
570 local_irq_restore(flags),
571 local_irq_save(flags));
572 }
573 }
574
575 local_irq_restore(flags);
576 if (!falcon_got_lock)
577 panic("Falcon SCSI: someone stole the lock :-(\n");
578}
579
580
581static int __init atari_scsi_detect(struct scsi_host_template *host)
582{
583 static int called = 0;
584 struct Scsi_Host *instance;
585
586 if (!MACH_IS_ATARI ||
587 (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) ||
588 called)
589 return 0;
590
591 host->proc_name = "Atari";
592
593 atari_scsi_reg_read = IS_A_TT() ? atari_scsi_tt_reg_read :
594 atari_scsi_falcon_reg_read;
595 atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write :
596 atari_scsi_falcon_reg_write;
597
598 /* setup variables */
599 host->can_queue =
600 (setup_can_queue > 0) ? setup_can_queue :
601 IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE;
602 host->cmd_per_lun =
603 (setup_cmd_per_lun > 0) ? setup_cmd_per_lun :
604 IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN;
605 /* Force sg_tablesize to 0 on a Falcon! */
606 host->sg_tablesize =
607 !IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE :
608 (setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE;
609
610 if (setup_hostid >= 0)
611 host->this_id = setup_hostid;
612 else {
613 /* use 7 as default */
614 host->this_id = 7;
615 /* Test if a host id is set in the NVRam */
616 if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
617 unsigned char b = nvram_read_byte( 14 );
618 /* Arbitration enabled? (for TOS) If yes, use configured host ID */
619 if (b & 0x80)
620 host->this_id = b & 7;
621 }
622 }
623
624#ifdef SUPPORT_TAGS
625 if (setup_use_tagged_queuing < 0)
626 setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING;
627#endif
628#ifdef REAL_DMA
629 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
630 * memory block, since there's always ST-Ram in a Falcon), then allocate a
631 * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative
632 * Ram.
633 */
634 if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
635 !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
636 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
637 if (!atari_dma_buffer) {
638 printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM "
639 "double buffer\n");
640 return 0;
641 }
642 atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
643 atari_dma_orig_addr = 0;
644 }
645#endif
646 instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
647 if (instance == NULL) {
648 atari_stram_free(atari_dma_buffer);
649 atari_dma_buffer = 0;
650 return 0;
651 }
652 atari_scsi_host = instance;
653 /*
654 * Set irq to 0, to avoid that the mid-level code disables our interrupt
655 * during queue_command calls. This is completely unnecessary, and even
656 * worse causes bad problems on the Falcon, where the int is shared with
657 * IDE and floppy!
658 */
659 instance->irq = 0;
660
661#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
662 atari_scsi_reset_boot();
663#endif
664 NCR5380_init(instance, 0);
665
666 if (IS_A_TT()) {
667
668 /* This int is actually "pseudo-slow", i.e. it acts like a slow
669 * interrupt after having cleared the pending flag for the DMA
670 * interrupt. */
671 if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW,
672 "SCSI NCR5380", instance)) {
673 printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI);
674 scsi_unregister(atari_scsi_host);
675 atari_stram_free(atari_dma_buffer);
676 atari_dma_buffer = 0;
677 return 0;
678 }
679 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
680#ifdef REAL_DMA
681 tt_scsi_dma.dma_ctrl = 0;
682 atari_dma_residual = 0;
683
684 if (MACH_IS_MEDUSA) {
685 /* While the read overruns (described by Drew Eckhardt in
686 * NCR5380.c) never happened on TTs, they do in fact on the Medusa
687 * (This was the cause why SCSI didn't work right for so long
688 * there.) Since handling the overruns slows down a bit, I turned
689 * the #ifdef's into a runtime condition.
690 *
691 * In principle it should be sufficient to do max. 1 byte with
692 * PIO, but there is another problem on the Medusa with the DMA
693 * rest data register. So 'atari_read_overruns' is currently set
694 * to 4 to avoid having transfers that aren't a multiple of 4. If
695 * the rest data bug is fixed, this can be lowered to 1.
696 */
697 atari_read_overruns = 4;
698 }
699#endif /*REAL_DMA*/
700 } else { /* ! IS_A_TT */
701
702 /* Nothing to do for the interrupt: the ST-DMA is initialized
703 * already by atari_init_INTS()
704 */
705
706#ifdef REAL_DMA
707 atari_dma_residual = 0;
708 atari_dma_active = 0;
709 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
710 : 0xff000000);
711#endif
712 }
713
714 printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d "
715#ifdef SUPPORT_TAGS
716 "TAGGED-QUEUING=%s "
717#endif
718 "HOSTID=%d",
719 instance->host_no, instance->hostt->can_queue,
720 instance->hostt->cmd_per_lun,
721 instance->hostt->sg_tablesize,
722#ifdef SUPPORT_TAGS
723 setup_use_tagged_queuing ? "yes" : "no",
724#endif
725 instance->hostt->this_id );
726 NCR5380_print_options(instance);
727 printk("\n");
728
729 called = 1;
730 return 1;
731}
732
733static int atari_scsi_release(struct Scsi_Host *sh)
734{
735 if (IS_A_TT())
736 free_irq(IRQ_TT_MFP_SCSI, sh);
737 if (atari_dma_buffer)
738 atari_stram_free(atari_dma_buffer);
739 NCR5380_exit(sh);
740 return 1;
741}
742
743#ifndef MODULE
744static int __init atari_scsi_setup(char *str)
745{
746 /* Format of atascsi parameter is:
747 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
748 * Defaults depend on TT or Falcon, hostid determined at run time.
749 * Negative values mean don't change.
750 */
751 int ints[6];
752
753 get_options(str, ARRAY_SIZE(ints), ints);
754
755 if (ints[0] < 1) {
756 printk("atari_scsi_setup: no arguments!\n");
757 return 0;
758 }
759
760 if (ints[0] >= 1) {
761 if (ints[1] > 0)
762 /* no limits on this, just > 0 */
763 setup_can_queue = ints[1];
764 }
765 if (ints[0] >= 2) {
766 if (ints[2] > 0)
767 setup_cmd_per_lun = ints[2];
768 }
769 if (ints[0] >= 3) {
770 if (ints[3] >= 0) {
771 setup_sg_tablesize = ints[3];
772 /* Must be <= SG_ALL (255) */
773 if (setup_sg_tablesize > SG_ALL)
774 setup_sg_tablesize = SG_ALL;
775 }
776 }
777 if (ints[0] >= 4) {
778 /* Must be between 0 and 7 */
779 if (ints[4] >= 0 && ints[4] <= 7)
780 setup_hostid = ints[4];
781 else if (ints[4] > 7)
782 printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]);
783 }
784#ifdef SUPPORT_TAGS
785 if (ints[0] >= 5) {
786 if (ints[5] >= 0)
787 setup_use_tagged_queuing = !!ints[5];
788 }
789#endif
790
791 return 1;
792}
793
794__setup("atascsi=", atari_scsi_setup);
795#endif /* !MODULE */
796
797static int atari_scsi_bus_reset(Scsi_Cmnd *cmd)
798{
799 int rv;
800 struct NCR5380_hostdata *hostdata =
801 (struct NCR5380_hostdata *)cmd->device->host->hostdata;
802
803 /* For doing the reset, SCSI interrupts must be disabled first,
804 * since the 5380 raises its IRQ line while _RST is active and we
805 * can't disable interrupts completely, since we need the timer.
806 */
807 /* And abort a maybe active DMA transfer */
808 if (IS_A_TT()) {
809 atari_turnoff_irq(IRQ_TT_MFP_SCSI);
810#ifdef REAL_DMA
811 tt_scsi_dma.dma_ctrl = 0;
812#endif /* REAL_DMA */
813 } else {
814 atari_turnoff_irq(IRQ_MFP_FSCSI);
815#ifdef REAL_DMA
816 st_dma.dma_mode_status = 0x90;
817 atari_dma_active = 0;
818 atari_dma_orig_addr = NULL;
819#endif /* REAL_DMA */
820 }
821
822 rv = NCR5380_bus_reset(cmd);
823
824 /* Re-enable ints */
825 if (IS_A_TT()) {
826 atari_turnon_irq(IRQ_TT_MFP_SCSI);
827 } else {
828 atari_turnon_irq(IRQ_MFP_FSCSI);
829 }
830 if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS)
831 falcon_release_lock_if_possible(hostdata);
832
833 return rv;
834}
835
836
837#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
838static void __init atari_scsi_reset_boot(void)
839{
840 unsigned long end;
841
842 /*
843 * Do a SCSI reset to clean up the bus during initialization. No messing
844 * with the queues, interrupts, or locks necessary here.
845 */
846
847 printk("Atari SCSI: resetting the SCSI bus...");
848
849 /* get in phase */
850 NCR5380_write(TARGET_COMMAND_REG,
851 PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
852
853 /* assert RST */
854 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
855 /* The min. reset hold time is 25us, so 40us should be enough */
856 udelay(50);
857 /* reset RST and interrupt */
858 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
859 NCR5380_read(RESET_PARITY_INTERRUPT_REG);
860
861 end = jiffies + AFTER_RESET_DELAY;
862 while (time_before(jiffies, end))
863 barrier();
864
865 printk(" done\n");
866}
867#endif
868
869
870static const char *atari_scsi_info(struct Scsi_Host *host)
871{
872 /* atari_scsi_detect() is verbose enough... */
873 static const char string[] = "Atari native SCSI";
874 return string;
875}
876
877
878#if defined(REAL_DMA)
879
880static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
881 void *data, unsigned long count,
882 int dir)
883{
884 unsigned long addr = virt_to_phys(data);
885
886 DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
887 "dir = %d\n", instance->host_no, data, addr, count, dir);
888
889 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
890 /* If we have a non-DMAable address on a Falcon, use the dribble
891 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
892 * handler to copy data from the dribble buffer to the originally
893 * wanted address.
894 */
895 if (dir)
896 memcpy(atari_dma_buffer, data, count);
897 else
898 atari_dma_orig_addr = data;
899 addr = atari_dma_phys_buffer;
900 }
901
902 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
903
904 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
905 * it to the peripheral. (Must be done before DMA setup, since at least
906 * the ST-DMA begins to fill internal buffers right after setup. For
907 * reads, invalidate any cache, may be altered after DMA without CPU
908 * knowledge.
909 *
910 * ++roman: For the Medusa, there's no need at all for that cache stuff,
911 * because the hardware does bus snooping (fine!).
912 */
913 dma_cache_maintenance(addr, count, dir);
914
915 if (count == 0)
916 printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
917
918 if (IS_A_TT()) {
919 tt_scsi_dma.dma_ctrl = dir;
920 SCSI_DMA_WRITE_P(dma_addr, addr);
921 SCSI_DMA_WRITE_P(dma_cnt, count);
922 tt_scsi_dma.dma_ctrl = dir | 2;
923 } else { /* ! IS_A_TT */
924
925 /* set address */
926 SCSI_DMA_SETADR(addr);
927
928 /* toggle direction bit to clear FIFO and set DMA direction */
929 dir <<= 8;
930 st_dma.dma_mode_status = 0x90 | dir;
931 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
932 st_dma.dma_mode_status = 0x90 | dir;
933 udelay(40);
934 /* On writes, round up the transfer length to the next multiple of 512
935 * (see also comment at atari_dma_xfer_len()). */
936 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
937 udelay(40);
938 st_dma.dma_mode_status = 0x10 | dir;
939 udelay(40);
940 /* need not restore value of dir, only boolean value is tested */
941 atari_dma_active = 1;
942 }
943
944 return count;
945}
946
947
948static long atari_scsi_dma_residual(struct Scsi_Host *instance)
949{
950 return atari_dma_residual;
951}
952
953
954#define CMD_SURELY_BLOCK_MODE 0
955#define CMD_SURELY_BYTE_MODE 1
956#define CMD_MODE_UNKNOWN 2
957
958static int falcon_classify_cmd(Scsi_Cmnd *cmd)
959{
960 unsigned char opcode = cmd->cmnd[0];
961
962 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
963 opcode == READ_BUFFER)
964 return CMD_SURELY_BYTE_MODE;
965 else if (opcode == READ_6 || opcode == READ_10 ||
966 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
967 opcode == RECOVER_BUFFERED_DATA) {
968 /* In case of a sequential-access target (tape), special care is
969 * needed here: The transfer is block-mode only if the 'fixed' bit is
970 * set! */
971 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
972 return CMD_SURELY_BYTE_MODE;
973 else
974 return CMD_SURELY_BLOCK_MODE;
975 } else
976 return CMD_MODE_UNKNOWN;
977}
978
979
980/* This function calculates the number of bytes that can be transferred via
981 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
982 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
983 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
984 * possible on the Falcon, since that would require to program the DMA for
985 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
986 * the overrun problem, so this question is academic :-)
987 */
988
989static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
990 Scsi_Cmnd *cmd, int write_flag)
991{
992 unsigned long possible_len, limit;
993
994 if (IS_A_TT())
995 /* TT SCSI DMA can transfer arbitrary #bytes */
996 return wanted_len;
997
998 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
999 * 255*512 bytes, but this should be enough)
1000 *
1001 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
1002 * that return a number of bytes which cannot be known beforehand. In this
1003 * case, the given transfer length is an "allocation length". Now it
1004 * can happen that this allocation length is a multiple of 512 bytes and
1005 * the DMA is used. But if not n*512 bytes really arrive, some input data
1006 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
1007 * between commands that do block transfers and those that do byte
1008 * transfers. But this isn't easy... there are lots of vendor specific
1009 * commands, and the user can issue any command via the
1010 * SCSI_IOCTL_SEND_COMMAND.
1011 *
1012 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
1013 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
1014 * and 3), the thing to do is obvious: allow any number of blocks via DMA
1015 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
1016 * the transfer (allocation) length is < 1024, hoping that no cmd. not
1017 * explicitly known as byte mode have such big allocation lengths...
1018 * BTW, all the discussion above applies only to reads. DMA writes are
1019 * unproblematic anyways, since the targets aborts the transfer after
1020 * receiving a sufficient number of bytes.
1021 *
1022 * Another point: If the transfer is from/to an non-ST-RAM address, we
1023 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
1024 */
1025
1026 if (write_flag) {
1027 /* Write operation can always use the DMA, but the transfer size must
1028 * be rounded up to the next multiple of 512 (atari_dma_setup() does
1029 * this).
1030 */
1031 possible_len = wanted_len;
1032 } else {
1033 /* Read operations: if the wanted transfer length is not a multiple of
1034 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
1035 * (no interrupt on DMA finished!)
1036 */
1037 if (wanted_len & 0x1ff)
1038 possible_len = 0;
1039 else {
1040 /* Now classify the command (see above) and decide whether it is
1041 * allowed to do DMA at all */
1042 switch (falcon_classify_cmd(cmd)) {
1043 case CMD_SURELY_BLOCK_MODE:
1044 possible_len = wanted_len;
1045 break;
1046 case CMD_SURELY_BYTE_MODE:
1047 possible_len = 0; /* DMA prohibited */
1048 break;
1049 case CMD_MODE_UNKNOWN:
1050 default:
1051 /* For unknown commands assume block transfers if the transfer
1052 * size/allocation length is >= 1024 */
1053 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
1054 break;
1055 }
1056 }
1057 }
1058
1059 /* Last step: apply the hard limit on DMA transfers */
1060 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
1061 STRAM_BUFFER_SIZE : 255*512;
1062 if (possible_len > limit)
1063 possible_len = limit;
1064
1065 if (possible_len != wanted_len)
1066 DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes "
1067 "instead of %ld\n", possible_len, wanted_len);
1068
1069 return possible_len;
1070}
1071
1072
1073#endif /* REAL_DMA */
1074
1075
1076/* NCR5380 register access functions
1077 *
1078 * There are separate functions for TT and Falcon, because the access
1079 * methods are quite different. The calling macros NCR5380_read and
1080 * NCR5380_write call these functions via function pointers.
1081 */
1082
1083static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
1084{
1085 return tt_scsi_regp[reg * 2];
1086}
1087
1088static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
1089{
1090 tt_scsi_regp[reg * 2] = value;
1091}
1092
1093static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
1094{
1095 dma_wd.dma_mode_status= (u_short)(0x88 + reg);
1096 return (u_char)dma_wd.fdc_acces_seccount;
1097}
1098
1099static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
1100{
1101 dma_wd.dma_mode_status = (u_short)(0x88 + reg);
1102 dma_wd.fdc_acces_seccount = (u_short)value;
1103}
1104
1105
1106#include "atari_NCR5380.c"
1107
1108static struct scsi_host_template driver_template = {
1109 .show_info = atari_scsi_show_info,
1110 .name = "Atari native SCSI",
1111 .detect = atari_scsi_detect,
1112 .release = atari_scsi_release,
1113 .info = atari_scsi_info,
1114 .queuecommand = atari_scsi_queue_command,
1115 .eh_abort_handler = atari_scsi_abort,
1116 .eh_bus_reset_handler = atari_scsi_bus_reset,
1117 .can_queue = 0, /* initialized at run-time */
1118 .this_id = 0, /* initialized at run-time */
1119 .sg_tablesize = 0, /* initialized at run-time */
1120 .cmd_per_lun = 0, /* initialized at run-time */
1121 .use_clustering = DISABLE_CLUSTERING
1122};
1123
1124
1125#include "scsi_module.c"
1126
1127MODULE_LICENSE("GPL");