Loading...
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#include <linux/module.h>
68#include <linux/types.h>
69#include <linux/blkdev.h>
70#include <linux/interrupt.h>
71#include <linux/init.h>
72#include <linux/nvram.h>
73#include <linux/bitops.h>
74#include <linux/wait.h>
75#include <linux/platform_device.h>
76
77#include <asm/setup.h>
78#include <asm/atarihw.h>
79#include <asm/atariints.h>
80#include <asm/atari_stdma.h>
81#include <asm/atari_stram.h>
82#include <asm/io.h>
83
84#include <scsi/scsi_host.h>
85
86/* Definitions for the core NCR5380 driver. */
87
88#define REAL_DMA
89#define SUPPORT_TAGS
90#define MAX_TAGS 32
91#define DMA_MIN_SIZE 32
92
93#define NCR5380_implementation_fields /* none */
94
95#define NCR5380_read(reg) atari_scsi_reg_read(reg)
96#define NCR5380_write(reg, value) atari_scsi_reg_write(reg, value)
97
98#define NCR5380_queue_command atari_scsi_queue_command
99#define NCR5380_abort atari_scsi_abort
100#define NCR5380_info atari_scsi_info
101
102#define NCR5380_dma_read_setup(instance, data, count) \
103 atari_scsi_dma_setup(instance, data, count, 0)
104#define NCR5380_dma_write_setup(instance, data, count) \
105 atari_scsi_dma_setup(instance, data, count, 1)
106#define NCR5380_dma_residual(instance) \
107 atari_scsi_dma_residual(instance)
108#define NCR5380_dma_xfer_len(instance, cmd, phase) \
109 atari_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & SR_IO))
110
111#define NCR5380_acquire_dma_irq(instance) falcon_get_lock(instance)
112#define NCR5380_release_dma_irq(instance) falcon_release_lock()
113
114#include "NCR5380.h"
115
116
117#define IS_A_TT() ATARIHW_PRESENT(TT_SCSI)
118
119#define SCSI_DMA_WRITE_P(elt,val) \
120 do { \
121 unsigned long v = val; \
122 tt_scsi_dma.elt##_lo = v & 0xff; \
123 v >>= 8; \
124 tt_scsi_dma.elt##_lmd = v & 0xff; \
125 v >>= 8; \
126 tt_scsi_dma.elt##_hmd = v & 0xff; \
127 v >>= 8; \
128 tt_scsi_dma.elt##_hi = v & 0xff; \
129 } while(0)
130
131#define SCSI_DMA_READ_P(elt) \
132 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \
133 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \
134 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \
135 (unsigned long)tt_scsi_dma.elt##_lo)
136
137
138static inline void SCSI_DMA_SETADR(unsigned long adr)
139{
140 st_dma.dma_lo = (unsigned char)adr;
141 MFPDELAY();
142 adr >>= 8;
143 st_dma.dma_md = (unsigned char)adr;
144 MFPDELAY();
145 adr >>= 8;
146 st_dma.dma_hi = (unsigned char)adr;
147 MFPDELAY();
148}
149
150static inline unsigned long SCSI_DMA_GETADR(void)
151{
152 unsigned long adr;
153 adr = st_dma.dma_lo;
154 MFPDELAY();
155 adr |= (st_dma.dma_md & 0xff) << 8;
156 MFPDELAY();
157 adr |= (st_dma.dma_hi & 0xff) << 16;
158 MFPDELAY();
159 return adr;
160}
161
162#ifdef REAL_DMA
163static void atari_scsi_fetch_restbytes(void);
164#endif
165
166static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
167static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
168
169#ifdef REAL_DMA
170static unsigned long atari_dma_residual, atari_dma_startaddr;
171static short atari_dma_active;
172/* pointer to the dribble buffer */
173static char *atari_dma_buffer;
174/* precalculated physical address of the dribble buffer */
175static unsigned long atari_dma_phys_buffer;
176/* != 0 tells the Falcon int handler to copy data from the dribble buffer */
177static char *atari_dma_orig_addr;
178/* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
179 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
180 * cases where requests to physical contiguous buffers have been merged, this
181 * request is <= 4k (one page). So I don't think we have to split transfers
182 * just due to this buffer size...
183 */
184#define STRAM_BUFFER_SIZE (4096)
185/* mask for address bits that can't be used with the ST-DMA */
186static unsigned long atari_dma_stram_mask;
187#define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
188#endif
189
190static int setup_can_queue = -1;
191module_param(setup_can_queue, int, 0);
192static int setup_cmd_per_lun = -1;
193module_param(setup_cmd_per_lun, int, 0);
194static int setup_sg_tablesize = -1;
195module_param(setup_sg_tablesize, int, 0);
196static int setup_use_tagged_queuing = -1;
197module_param(setup_use_tagged_queuing, int, 0);
198static int setup_hostid = -1;
199module_param(setup_hostid, int, 0);
200static int setup_toshiba_delay = -1;
201module_param(setup_toshiba_delay, int, 0);
202
203
204#if defined(REAL_DMA)
205
206static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
207{
208 int i;
209 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
210
211 if (dma_stat & 0x01) {
212
213 /* A bus error happens when DMA-ing from the last page of a
214 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
215 * Check for this case:
216 */
217
218 for (i = 0; i < m68k_num_memory; ++i) {
219 end_addr = m68k_memory[i].addr + m68k_memory[i].size;
220 if (end_addr <= addr && addr <= end_addr + 4)
221 return 1;
222 }
223 }
224 return 0;
225}
226
227
228#if 0
229/* Dead code... wasn't called anyway :-) and causes some trouble, because at
230 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
231 * to clear the DMA int pending bit before it allows other level 6 interrupts.
232 */
233static void scsi_dma_buserr(int irq, void *dummy)
234{
235 unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
236
237 /* Don't do anything if a NCR interrupt is pending. Probably it's just
238 * masked... */
239 if (atari_irq_pending(IRQ_TT_MFP_SCSI))
240 return;
241
242 printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
243 SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
244 if (dma_stat & 0x80) {
245 if (!scsi_dma_is_ignored_buserr(dma_stat))
246 printk("SCSI DMA bus error -- bad DMA programming!\n");
247 } else {
248 /* Under normal circumstances we never should get to this point,
249 * since both interrupts are triggered simultaneously and the 5380
250 * int has higher priority. When this irq is handled, that DMA
251 * interrupt is cleared. So a warning message is printed here.
252 */
253 printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
254 }
255}
256#endif
257
258#endif
259
260
261static irqreturn_t scsi_tt_intr(int irq, void *dev)
262{
263#ifdef REAL_DMA
264 struct Scsi_Host *instance = dev;
265 struct NCR5380_hostdata *hostdata = shost_priv(instance);
266 int dma_stat;
267
268 dma_stat = tt_scsi_dma.dma_ctrl;
269
270 dsprintk(NDEBUG_INTR, instance, "NCR5380 interrupt, DMA status = %02x\n",
271 dma_stat & 0xff);
272
273 /* Look if it was the DMA that has interrupted: First possibility
274 * is that a bus error occurred...
275 */
276 if (dma_stat & 0x80) {
277 if (!scsi_dma_is_ignored_buserr(dma_stat)) {
278 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
279 SCSI_DMA_READ_P(dma_addr));
280 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
281 }
282 }
283
284 /* If the DMA is active but not finished, we have the case
285 * that some other 5380 interrupt occurred within the DMA transfer.
286 * This means we have residual bytes, if the desired end address
287 * is not yet reached. Maybe we have to fetch some bytes from the
288 * rest data register, too. The residual must be calculated from
289 * the address pointer, not the counter register, because only the
290 * addr reg counts bytes not yet written and pending in the rest
291 * data reg!
292 */
293 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
294 atari_dma_residual = hostdata->dma_len -
295 (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
296
297 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
298 atari_dma_residual);
299
300 if ((signed int)atari_dma_residual < 0)
301 atari_dma_residual = 0;
302 if ((dma_stat & 1) == 0) {
303 /*
304 * After read operations, we maybe have to
305 * transport some rest bytes
306 */
307 atari_scsi_fetch_restbytes();
308 } else {
309 /*
310 * There seems to be a nasty bug in some SCSI-DMA/NCR
311 * combinations: If a target disconnects while a write
312 * operation is going on, the address register of the
313 * DMA may be a few bytes farer than it actually read.
314 * This is probably due to DMA prefetching and a delay
315 * between DMA and NCR. Experiments showed that the
316 * dma_addr is 9 bytes to high, but this could vary.
317 * The problem is, that the residual is thus calculated
318 * wrong and the next transfer will start behind where
319 * it should. So we round up the residual to the next
320 * multiple of a sector size, if it isn't already a
321 * multiple and the originally expected transfer size
322 * was. The latter condition is there to ensure that
323 * the correction is taken only for "real" data
324 * transfers and not for, e.g., the parameters of some
325 * other command. These shouldn't disconnect anyway.
326 */
327 if (atari_dma_residual & 0x1ff) {
328 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, "
329 "difference %ld bytes\n",
330 512 - (atari_dma_residual & 0x1ff));
331 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
332 }
333 }
334 tt_scsi_dma.dma_ctrl = 0;
335 }
336
337 /* If the DMA is finished, fetch the rest bytes and turn it off */
338 if (dma_stat & 0x40) {
339 atari_dma_residual = 0;
340 if ((dma_stat & 1) == 0)
341 atari_scsi_fetch_restbytes();
342 tt_scsi_dma.dma_ctrl = 0;
343 }
344
345#endif /* REAL_DMA */
346
347 NCR5380_intr(irq, dev);
348
349 return IRQ_HANDLED;
350}
351
352
353static irqreturn_t scsi_falcon_intr(int irq, void *dev)
354{
355#ifdef REAL_DMA
356 struct Scsi_Host *instance = dev;
357 struct NCR5380_hostdata *hostdata = shost_priv(instance);
358 int dma_stat;
359
360 /* Turn off DMA and select sector counter register before
361 * accessing the status register (Atari recommendation!)
362 */
363 st_dma.dma_mode_status = 0x90;
364 dma_stat = st_dma.dma_mode_status;
365
366 /* Bit 0 indicates some error in the DMA process... don't know
367 * what happened exactly (no further docu).
368 */
369 if (!(dma_stat & 0x01)) {
370 /* DMA error */
371 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
372 }
373
374 /* If the DMA was active, but now bit 1 is not clear, it is some
375 * other 5380 interrupt that finishes the DMA transfer. We have to
376 * calculate the number of residual bytes and give a warning if
377 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
378 */
379 if (atari_dma_active && (dma_stat & 0x02)) {
380 unsigned long transferred;
381
382 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
383 /* The ST-DMA address is incremented in 2-byte steps, but the
384 * data are written only in 16-byte chunks. If the number of
385 * transferred bytes is not divisible by 16, the remainder is
386 * lost somewhere in outer space.
387 */
388 if (transferred & 15)
389 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
390 "ST-DMA fifo\n", transferred & 15);
391
392 atari_dma_residual = hostdata->dma_len - transferred;
393 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
394 atari_dma_residual);
395 } else
396 atari_dma_residual = 0;
397 atari_dma_active = 0;
398
399 if (atari_dma_orig_addr) {
400 /* If the dribble buffer was used on a read operation, copy the DMA-ed
401 * data to the original destination address.
402 */
403 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
404 hostdata->dma_len - atari_dma_residual);
405 atari_dma_orig_addr = NULL;
406 }
407
408#endif /* REAL_DMA */
409
410 NCR5380_intr(irq, dev);
411
412 return IRQ_HANDLED;
413}
414
415
416#ifdef REAL_DMA
417static void atari_scsi_fetch_restbytes(void)
418{
419 int nr;
420 char *src, *dst;
421 unsigned long phys_dst;
422
423 /* fetch rest bytes in the DMA register */
424 phys_dst = SCSI_DMA_READ_P(dma_addr);
425 nr = phys_dst & 3;
426 if (nr) {
427 /* there are 'nr' bytes left for the last long address
428 before the DMA pointer */
429 phys_dst ^= nr;
430 dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
431 nr, phys_dst);
432 /* The content of the DMA pointer is a physical address! */
433 dst = phys_to_virt(phys_dst);
434 dprintk(NDEBUG_DMA, " = virt addr %p\n", dst);
435 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
436 *dst++ = *src++;
437 }
438}
439#endif /* REAL_DMA */
440
441
442/* This function releases the lock on the DMA chip if there is no
443 * connected command and the disconnected queue is empty.
444 */
445
446static void falcon_release_lock(void)
447{
448 if (IS_A_TT())
449 return;
450
451 if (stdma_is_locked_by(scsi_falcon_intr))
452 stdma_release();
453}
454
455/* This function manages the locking of the ST-DMA.
456 * If the DMA isn't locked already for SCSI, it tries to lock it by
457 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
458 * there are other drivers waiting for the chip, we do not issue the
459 * command immediately but tell the SCSI mid-layer to defer.
460 */
461
462static int falcon_get_lock(struct Scsi_Host *instance)
463{
464 if (IS_A_TT())
465 return 1;
466
467 if (in_interrupt())
468 return stdma_try_lock(scsi_falcon_intr, instance);
469
470 stdma_lock(scsi_falcon_intr, instance);
471 return 1;
472}
473
474#ifndef MODULE
475static int __init atari_scsi_setup(char *str)
476{
477 /* Format of atascsi parameter is:
478 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
479 * Defaults depend on TT or Falcon, determined at run time.
480 * Negative values mean don't change.
481 */
482 int ints[8];
483
484 get_options(str, ARRAY_SIZE(ints), ints);
485
486 if (ints[0] < 1) {
487 printk("atari_scsi_setup: no arguments!\n");
488 return 0;
489 }
490 if (ints[0] >= 1)
491 setup_can_queue = ints[1];
492 if (ints[0] >= 2)
493 setup_cmd_per_lun = ints[2];
494 if (ints[0] >= 3)
495 setup_sg_tablesize = ints[3];
496 if (ints[0] >= 4)
497 setup_hostid = ints[4];
498 if (ints[0] >= 5)
499 setup_use_tagged_queuing = ints[5];
500 /* ints[6] (use_pdma) is ignored */
501 if (ints[0] >= 7)
502 setup_toshiba_delay = ints[7];
503
504 return 1;
505}
506
507__setup("atascsi=", atari_scsi_setup);
508#endif /* !MODULE */
509
510
511#if defined(REAL_DMA)
512
513static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
514 void *data, unsigned long count,
515 int dir)
516{
517 unsigned long addr = virt_to_phys(data);
518
519 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
520 "dir = %d\n", instance->host_no, data, addr, count, dir);
521
522 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
523 /* If we have a non-DMAable address on a Falcon, use the dribble
524 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
525 * handler to copy data from the dribble buffer to the originally
526 * wanted address.
527 */
528 if (dir)
529 memcpy(atari_dma_buffer, data, count);
530 else
531 atari_dma_orig_addr = data;
532 addr = atari_dma_phys_buffer;
533 }
534
535 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
536
537 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
538 * it to the peripheral. (Must be done before DMA setup, since at least
539 * the ST-DMA begins to fill internal buffers right after setup. For
540 * reads, invalidate any cache, may be altered after DMA without CPU
541 * knowledge.
542 *
543 * ++roman: For the Medusa, there's no need at all for that cache stuff,
544 * because the hardware does bus snooping (fine!).
545 */
546 dma_cache_maintenance(addr, count, dir);
547
548 if (count == 0)
549 printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
550
551 if (IS_A_TT()) {
552 tt_scsi_dma.dma_ctrl = dir;
553 SCSI_DMA_WRITE_P(dma_addr, addr);
554 SCSI_DMA_WRITE_P(dma_cnt, count);
555 tt_scsi_dma.dma_ctrl = dir | 2;
556 } else { /* ! IS_A_TT */
557
558 /* set address */
559 SCSI_DMA_SETADR(addr);
560
561 /* toggle direction bit to clear FIFO and set DMA direction */
562 dir <<= 8;
563 st_dma.dma_mode_status = 0x90 | dir;
564 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
565 st_dma.dma_mode_status = 0x90 | dir;
566 udelay(40);
567 /* On writes, round up the transfer length to the next multiple of 512
568 * (see also comment at atari_dma_xfer_len()). */
569 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
570 udelay(40);
571 st_dma.dma_mode_status = 0x10 | dir;
572 udelay(40);
573 /* need not restore value of dir, only boolean value is tested */
574 atari_dma_active = 1;
575 }
576
577 return count;
578}
579
580
581static long atari_scsi_dma_residual(struct Scsi_Host *instance)
582{
583 return atari_dma_residual;
584}
585
586
587#define CMD_SURELY_BLOCK_MODE 0
588#define CMD_SURELY_BYTE_MODE 1
589#define CMD_MODE_UNKNOWN 2
590
591static int falcon_classify_cmd(struct scsi_cmnd *cmd)
592{
593 unsigned char opcode = cmd->cmnd[0];
594
595 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
596 opcode == READ_BUFFER)
597 return CMD_SURELY_BYTE_MODE;
598 else if (opcode == READ_6 || opcode == READ_10 ||
599 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
600 opcode == RECOVER_BUFFERED_DATA) {
601 /* In case of a sequential-access target (tape), special care is
602 * needed here: The transfer is block-mode only if the 'fixed' bit is
603 * set! */
604 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
605 return CMD_SURELY_BYTE_MODE;
606 else
607 return CMD_SURELY_BLOCK_MODE;
608 } else
609 return CMD_MODE_UNKNOWN;
610}
611
612
613/* This function calculates the number of bytes that can be transferred via
614 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
615 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
616 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
617 * possible on the Falcon, since that would require to program the DMA for
618 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
619 * the overrun problem, so this question is academic :-)
620 */
621
622static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
623 struct scsi_cmnd *cmd, int write_flag)
624{
625 unsigned long possible_len, limit;
626
627 if (IS_A_TT())
628 /* TT SCSI DMA can transfer arbitrary #bytes */
629 return wanted_len;
630
631 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
632 * 255*512 bytes, but this should be enough)
633 *
634 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
635 * that return a number of bytes which cannot be known beforehand. In this
636 * case, the given transfer length is an "allocation length". Now it
637 * can happen that this allocation length is a multiple of 512 bytes and
638 * the DMA is used. But if not n*512 bytes really arrive, some input data
639 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
640 * between commands that do block transfers and those that do byte
641 * transfers. But this isn't easy... there are lots of vendor specific
642 * commands, and the user can issue any command via the
643 * SCSI_IOCTL_SEND_COMMAND.
644 *
645 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
646 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
647 * and 3), the thing to do is obvious: allow any number of blocks via DMA
648 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
649 * the transfer (allocation) length is < 1024, hoping that no cmd. not
650 * explicitly known as byte mode have such big allocation lengths...
651 * BTW, all the discussion above applies only to reads. DMA writes are
652 * unproblematic anyways, since the targets aborts the transfer after
653 * receiving a sufficient number of bytes.
654 *
655 * Another point: If the transfer is from/to an non-ST-RAM address, we
656 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
657 */
658
659 if (write_flag) {
660 /* Write operation can always use the DMA, but the transfer size must
661 * be rounded up to the next multiple of 512 (atari_dma_setup() does
662 * this).
663 */
664 possible_len = wanted_len;
665 } else {
666 /* Read operations: if the wanted transfer length is not a multiple of
667 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
668 * (no interrupt on DMA finished!)
669 */
670 if (wanted_len & 0x1ff)
671 possible_len = 0;
672 else {
673 /* Now classify the command (see above) and decide whether it is
674 * allowed to do DMA at all */
675 switch (falcon_classify_cmd(cmd)) {
676 case CMD_SURELY_BLOCK_MODE:
677 possible_len = wanted_len;
678 break;
679 case CMD_SURELY_BYTE_MODE:
680 possible_len = 0; /* DMA prohibited */
681 break;
682 case CMD_MODE_UNKNOWN:
683 default:
684 /* For unknown commands assume block transfers if the transfer
685 * size/allocation length is >= 1024 */
686 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
687 break;
688 }
689 }
690 }
691
692 /* Last step: apply the hard limit on DMA transfers */
693 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
694 STRAM_BUFFER_SIZE : 255*512;
695 if (possible_len > limit)
696 possible_len = limit;
697
698 if (possible_len != wanted_len)
699 dprintk(NDEBUG_DMA, "Sorry, must cut DMA transfer size to %ld bytes "
700 "instead of %ld\n", possible_len, wanted_len);
701
702 return possible_len;
703}
704
705
706#endif /* REAL_DMA */
707
708
709/* NCR5380 register access functions
710 *
711 * There are separate functions for TT and Falcon, because the access
712 * methods are quite different. The calling macros NCR5380_read and
713 * NCR5380_write call these functions via function pointers.
714 */
715
716static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
717{
718 return tt_scsi_regp[reg * 2];
719}
720
721static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
722{
723 tt_scsi_regp[reg * 2] = value;
724}
725
726static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
727{
728 dma_wd.dma_mode_status= (u_short)(0x88 + reg);
729 return (u_char)dma_wd.fdc_acces_seccount;
730}
731
732static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
733{
734 dma_wd.dma_mode_status = (u_short)(0x88 + reg);
735 dma_wd.fdc_acces_seccount = (u_short)value;
736}
737
738
739#include "atari_NCR5380.c"
740
741static int atari_scsi_bus_reset(struct scsi_cmnd *cmd)
742{
743 int rv;
744 unsigned long flags;
745
746 local_irq_save(flags);
747
748#ifdef REAL_DMA
749 /* Abort a maybe active DMA transfer */
750 if (IS_A_TT()) {
751 tt_scsi_dma.dma_ctrl = 0;
752 } else {
753 st_dma.dma_mode_status = 0x90;
754 atari_dma_active = 0;
755 atari_dma_orig_addr = NULL;
756 }
757#endif
758
759 rv = NCR5380_bus_reset(cmd);
760
761 /* The 5380 raises its IRQ line while _RST is active but the ST DMA
762 * "lock" has been released so this interrupt may end up handled by
763 * floppy or IDE driver (if one of them holds the lock). The NCR5380
764 * interrupt flag has been cleared already.
765 */
766
767 local_irq_restore(flags);
768
769 return rv;
770}
771
772#define DRV_MODULE_NAME "atari_scsi"
773#define PFX DRV_MODULE_NAME ": "
774
775static struct scsi_host_template atari_scsi_template = {
776 .module = THIS_MODULE,
777 .proc_name = DRV_MODULE_NAME,
778 .name = "Atari native SCSI",
779 .info = atari_scsi_info,
780 .queuecommand = atari_scsi_queue_command,
781 .eh_abort_handler = atari_scsi_abort,
782 .eh_bus_reset_handler = atari_scsi_bus_reset,
783 .this_id = 7,
784 .use_clustering = DISABLE_CLUSTERING,
785 .cmd_size = NCR5380_CMD_SIZE,
786};
787
788static int __init atari_scsi_probe(struct platform_device *pdev)
789{
790 struct Scsi_Host *instance;
791 int error;
792 struct resource *irq;
793 int host_flags = 0;
794
795 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
796 if (!irq)
797 return -ENODEV;
798
799 if (ATARIHW_PRESENT(TT_SCSI)) {
800 atari_scsi_reg_read = atari_scsi_tt_reg_read;
801 atari_scsi_reg_write = atari_scsi_tt_reg_write;
802 } else {
803 atari_scsi_reg_read = atari_scsi_falcon_reg_read;
804 atari_scsi_reg_write = atari_scsi_falcon_reg_write;
805 }
806
807 /* The values for CMD_PER_LUN and CAN_QUEUE are somehow arbitrary.
808 * Higher values should work, too; try it!
809 * (But cmd_per_lun costs memory!)
810 *
811 * But there seems to be a bug somewhere that requires CAN_QUEUE to be
812 * 2*CMD_PER_LUN. At least on a TT, no spurious timeouts seen since
813 * changed CMD_PER_LUN...
814 *
815 * Note: The Falcon currently uses 8/1 setting due to unsolved problems
816 * with cmd_per_lun != 1
817 */
818 if (ATARIHW_PRESENT(TT_SCSI)) {
819 atari_scsi_template.can_queue = 16;
820 atari_scsi_template.cmd_per_lun = 8;
821 atari_scsi_template.sg_tablesize = SG_ALL;
822 } else {
823 atari_scsi_template.can_queue = 8;
824 atari_scsi_template.cmd_per_lun = 1;
825 atari_scsi_template.sg_tablesize = SG_NONE;
826 }
827
828 if (setup_can_queue > 0)
829 atari_scsi_template.can_queue = setup_can_queue;
830
831 if (setup_cmd_per_lun > 0)
832 atari_scsi_template.cmd_per_lun = setup_cmd_per_lun;
833
834 /* Leave sg_tablesize at 0 on a Falcon! */
835 if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize >= 0)
836 atari_scsi_template.sg_tablesize = setup_sg_tablesize;
837
838 if (setup_hostid >= 0) {
839 atari_scsi_template.this_id = setup_hostid & 7;
840 } else {
841 /* Test if a host id is set in the NVRam */
842 if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
843 unsigned char b = nvram_read_byte(16);
844
845 /* Arbitration enabled? (for TOS)
846 * If yes, use configured host ID
847 */
848 if (b & 0x80)
849 atari_scsi_template.this_id = b & 7;
850 }
851 }
852
853
854#ifdef REAL_DMA
855 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
856 * memory block, since there's always ST-Ram in a Falcon), then
857 * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers
858 * from/to alternative Ram.
859 */
860 if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) &&
861 m68k_num_memory > 1) {
862 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
863 if (!atari_dma_buffer) {
864 pr_err(PFX "can't allocate ST-RAM double buffer\n");
865 return -ENOMEM;
866 }
867 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
868 atari_dma_orig_addr = 0;
869 }
870#endif
871
872 instance = scsi_host_alloc(&atari_scsi_template,
873 sizeof(struct NCR5380_hostdata));
874 if (!instance) {
875 error = -ENOMEM;
876 goto fail_alloc;
877 }
878
879 instance->irq = irq->start;
880
881 host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
882#ifdef SUPPORT_TAGS
883 host_flags |= setup_use_tagged_queuing > 0 ? FLAG_TAGGED_QUEUING : 0;
884#endif
885 host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
886
887 error = NCR5380_init(instance, host_flags);
888 if (error)
889 goto fail_init;
890
891 if (IS_A_TT()) {
892 error = request_irq(instance->irq, scsi_tt_intr, 0,
893 "NCR5380", instance);
894 if (error) {
895 pr_err(PFX "request irq %d failed, aborting\n",
896 instance->irq);
897 goto fail_irq;
898 }
899 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
900#ifdef REAL_DMA
901 tt_scsi_dma.dma_ctrl = 0;
902 atari_dma_residual = 0;
903
904 /* While the read overruns (described by Drew Eckhardt in
905 * NCR5380.c) never happened on TTs, they do in fact on the
906 * Medusa (This was the cause why SCSI didn't work right for
907 * so long there.) Since handling the overruns slows down
908 * a bit, I turned the #ifdef's into a runtime condition.
909 *
910 * In principle it should be sufficient to do max. 1 byte with
911 * PIO, but there is another problem on the Medusa with the DMA
912 * rest data register. So read_overruns is currently set
913 * to 4 to avoid having transfers that aren't a multiple of 4.
914 * If the rest data bug is fixed, this can be lowered to 1.
915 */
916 if (MACH_IS_MEDUSA) {
917 struct NCR5380_hostdata *hostdata =
918 shost_priv(instance);
919
920 hostdata->read_overruns = 4;
921 }
922#endif
923 } else {
924 /* Nothing to do for the interrupt: the ST-DMA is initialized
925 * already.
926 */
927#ifdef REAL_DMA
928 atari_dma_residual = 0;
929 atari_dma_active = 0;
930 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
931 : 0xff000000);
932#endif
933 }
934
935 NCR5380_maybe_reset_bus(instance);
936
937 error = scsi_add_host(instance, NULL);
938 if (error)
939 goto fail_host;
940
941 platform_set_drvdata(pdev, instance);
942
943 scsi_scan_host(instance);
944 return 0;
945
946fail_host:
947 if (IS_A_TT())
948 free_irq(instance->irq, instance);
949fail_irq:
950 NCR5380_exit(instance);
951fail_init:
952 scsi_host_put(instance);
953fail_alloc:
954 if (atari_dma_buffer)
955 atari_stram_free(atari_dma_buffer);
956 return error;
957}
958
959static int __exit atari_scsi_remove(struct platform_device *pdev)
960{
961 struct Scsi_Host *instance = platform_get_drvdata(pdev);
962
963 scsi_remove_host(instance);
964 if (IS_A_TT())
965 free_irq(instance->irq, instance);
966 NCR5380_exit(instance);
967 scsi_host_put(instance);
968 if (atari_dma_buffer)
969 atari_stram_free(atari_dma_buffer);
970 return 0;
971}
972
973static struct platform_driver atari_scsi_driver = {
974 .remove = __exit_p(atari_scsi_remove),
975 .driver = {
976 .name = DRV_MODULE_NAME,
977 },
978};
979
980module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
981
982MODULE_ALIAS("platform:" DRV_MODULE_NAME);
983MODULE_LICENSE("GPL");