2 * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
4 * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
6 * Loosely based on the work of Robert De Vries' team and added:
8 * - Falcon support (untested yet!) ++bjoern fixed and now it works
9 * - lots of extensions and bug fixes.
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
18 /**************************************************************************/
20 /* Notes for Falcon SCSI: */
21 /* ---------------------- */
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. */
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 */
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. */
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! */
64 /**************************************************************************/
68 #include <linux/module.h>
70 /* For the Atari version, use only polled IO or REAL_DMA */
72 /* Support tagged queuing? (on devices that are able to... :-) */
76 #include <linux/types.h>
77 #include <linux/stddef.h>
78 #include <linux/ctype.h>
79 #include <linux/delay.h>
81 #include <linux/blkdev.h>
82 #include <linux/interrupt.h>
83 #include <linux/init.h>
84 #include <linux/nvram.h>
85 #include <linux/bitops.h>
86 #include <linux/wait.h>
88 #include <asm/setup.h>
89 #include <asm/atarihw.h>
90 #include <asm/atariints.h>
92 #include <asm/pgtable.h>
94 #include <asm/traps.h>
97 #include <scsi/scsi_host.h>
98 #include "atari_scsi.h"
100 #include <asm/atari_stdma.h>
101 #include <asm/atari_stram.h>
104 #include <linux/stat.h>
106 #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI)
108 #define SCSI_DMA_WRITE_P(elt,val) \
110 unsigned long v = val; \
111 tt_scsi_dma.elt##_lo = v & 0xff; \
113 tt_scsi_dma.elt##_lmd = v & 0xff; \
115 tt_scsi_dma.elt##_hmd = v & 0xff; \
117 tt_scsi_dma.elt##_hi = v & 0xff; \
120 #define SCSI_DMA_READ_P(elt) \
121 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \
122 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \
123 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \
124 (unsigned long)tt_scsi_dma.elt##_lo)
127 static inline void SCSI_DMA_SETADR(unsigned long adr)
129 st_dma.dma_lo = (unsigned char)adr;
132 st_dma.dma_md = (unsigned char)adr;
135 st_dma.dma_hi = (unsigned char)adr;
139 static inline unsigned long SCSI_DMA_GETADR(void)
144 adr |= (st_dma.dma_md & 0xff) << 8;
146 adr |= (st_dma.dma_hi & 0xff) << 16;
151 static inline void ENABLE_IRQ(void)
154 atari_enable_irq(IRQ_TT_MFP_SCSI);
156 atari_enable_irq(IRQ_MFP_FSCSI);
159 static inline void DISABLE_IRQ(void)
162 atari_disable_irq(IRQ_TT_MFP_SCSI);
164 atari_disable_irq(IRQ_MFP_FSCSI);
168 #define HOSTDATA_DMALEN (((struct NCR5380_hostdata *) \
169 (atari_scsi_host->hostdata))->dma_len)
171 /* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
172 * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
173 * need ten times the standard value... */
174 #ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
175 #define AFTER_RESET_DELAY (HZ/2)
177 #define AFTER_RESET_DELAY (5*HZ/2)
180 /***************************** Prototypes *****************************/
183 static void atari_scsi_fetch_restbytes(void);
185 static irqreturn_t scsi_tt_intr(int irq, void *dummy);
186 static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
187 static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
188 static void falcon_get_lock(void);
189 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
190 static void atari_scsi_reset_boot(void);
192 static unsigned char atari_scsi_tt_reg_read(unsigned char reg);
193 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value);
194 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg);
195 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value);
197 /************************* End of Prototypes **************************/
200 static struct Scsi_Host *atari_scsi_host;
201 static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
202 static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
205 static unsigned long atari_dma_residual, atari_dma_startaddr;
206 static short atari_dma_active;
207 /* pointer to the dribble buffer */
208 static char *atari_dma_buffer;
209 /* precalculated physical address of the dribble buffer */
210 static unsigned long atari_dma_phys_buffer;
211 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */
212 static char *atari_dma_orig_addr;
213 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
214 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
215 * cases where requests to physical contiguous buffers have been merged, this
216 * request is <= 4k (one page). So I don't think we have to split transfers
217 * just due to this buffer size...
219 #define STRAM_BUFFER_SIZE (4096)
220 /* mask for address bits that can't be used with the ST-DMA */
221 static unsigned long atari_dma_stram_mask;
222 #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
223 /* number of bytes to cut from a transfer to handle NCR overruns */
224 static int atari_read_overruns;
227 static int setup_can_queue = -1;
228 module_param(setup_can_queue, int, 0);
229 static int setup_cmd_per_lun = -1;
230 module_param(setup_cmd_per_lun, int, 0);
231 static int setup_sg_tablesize = -1;
232 module_param(setup_sg_tablesize, int, 0);
234 static int setup_use_tagged_queuing = -1;
235 module_param(setup_use_tagged_queuing, int, 0);
237 static int setup_hostid = -1;
238 module_param(setup_hostid, int, 0);
241 #if defined(REAL_DMA)
243 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
246 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
248 if (dma_stat & 0x01) {
250 /* A bus error happens when DMA-ing from the last page of a
251 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
252 * Check for this case:
255 for (i = 0; i < m68k_num_memory; ++i) {
256 end_addr = m68k_memory[i].addr + m68k_memory[i].size;
257 if (end_addr <= addr && addr <= end_addr + 4)
266 /* Dead code... wasn't called anyway :-) and causes some trouble, because at
267 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
268 * to clear the DMA int pending bit before it allows other level 6 interrupts.
270 static void scsi_dma_buserr(int irq, void *dummy)
272 unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
274 /* Don't do anything if a NCR interrupt is pending. Probably it's just
276 if (atari_irq_pending(IRQ_TT_MFP_SCSI))
279 printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
280 SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
281 if (dma_stat & 0x80) {
282 if (!scsi_dma_is_ignored_buserr(dma_stat))
283 printk("SCSI DMA bus error -- bad DMA programming!\n");
285 /* Under normal circumstances we never should get to this point,
286 * since both interrupts are triggered simultaneously and the 5380
287 * int has higher priority. When this irq is handled, that DMA
288 * interrupt is cleared. So a warning message is printed here.
290 printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
298 static irqreturn_t scsi_tt_intr(int irq, void *dummy)
303 dma_stat = tt_scsi_dma.dma_ctrl;
305 dprintk(NDEBUG_INTR, "scsi%d: NCR5380 interrupt, DMA status = %02x\n",
306 atari_scsi_host->host_no, dma_stat & 0xff);
308 /* Look if it was the DMA that has interrupted: First possibility
309 * is that a bus error occurred...
311 if (dma_stat & 0x80) {
312 if (!scsi_dma_is_ignored_buserr(dma_stat)) {
313 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
314 SCSI_DMA_READ_P(dma_addr));
315 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
319 /* If the DMA is active but not finished, we have the case
320 * that some other 5380 interrupt occurred within the DMA transfer.
321 * This means we have residual bytes, if the desired end address
322 * is not yet reached. Maybe we have to fetch some bytes from the
323 * rest data register, too. The residual must be calculated from
324 * the address pointer, not the counter register, because only the
325 * addr reg counts bytes not yet written and pending in the rest
328 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
329 atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
331 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
334 if ((signed int)atari_dma_residual < 0)
335 atari_dma_residual = 0;
336 if ((dma_stat & 1) == 0) {
338 * After read operations, we maybe have to
339 * transport some rest bytes
341 atari_scsi_fetch_restbytes();
344 * There seems to be a nasty bug in some SCSI-DMA/NCR
345 * combinations: If a target disconnects while a write
346 * operation is going on, the address register of the
347 * DMA may be a few bytes farer than it actually read.
348 * This is probably due to DMA prefetching and a delay
349 * between DMA and NCR. Experiments showed that the
350 * dma_addr is 9 bytes to high, but this could vary.
351 * The problem is, that the residual is thus calculated
352 * wrong and the next transfer will start behind where
353 * it should. So we round up the residual to the next
354 * multiple of a sector size, if it isn't already a
355 * multiple and the originally expected transfer size
356 * was. The latter condition is there to ensure that
357 * the correction is taken only for "real" data
358 * transfers and not for, e.g., the parameters of some
359 * other command. These shouldn't disconnect anyway.
361 if (atari_dma_residual & 0x1ff) {
362 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, "
363 "difference %ld bytes\n",
364 512 - (atari_dma_residual & 0x1ff));
365 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
368 tt_scsi_dma.dma_ctrl = 0;
371 /* If the DMA is finished, fetch the rest bytes and turn it off */
372 if (dma_stat & 0x40) {
373 atari_dma_residual = 0;
374 if ((dma_stat & 1) == 0)
375 atari_scsi_fetch_restbytes();
376 tt_scsi_dma.dma_ctrl = 0;
379 #endif /* REAL_DMA */
381 NCR5380_intr(irq, dummy);
384 /* To be sure the int is not masked */
385 atari_enable_irq(IRQ_TT_MFP_SCSI);
391 static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
396 /* Turn off DMA and select sector counter register before
397 * accessing the status register (Atari recommendation!)
399 st_dma.dma_mode_status = 0x90;
400 dma_stat = st_dma.dma_mode_status;
402 /* Bit 0 indicates some error in the DMA process... don't know
403 * what happened exactly (no further docu).
405 if (!(dma_stat & 0x01)) {
407 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
410 /* If the DMA was active, but now bit 1 is not clear, it is some
411 * other 5380 interrupt that finishes the DMA transfer. We have to
412 * calculate the number of residual bytes and give a warning if
413 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
415 if (atari_dma_active && (dma_stat & 0x02)) {
416 unsigned long transferred;
418 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
419 /* The ST-DMA address is incremented in 2-byte steps, but the
420 * data are written only in 16-byte chunks. If the number of
421 * transferred bytes is not divisible by 16, the remainder is
422 * lost somewhere in outer space.
424 if (transferred & 15)
425 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
426 "ST-DMA fifo\n", transferred & 15);
428 atari_dma_residual = HOSTDATA_DMALEN - transferred;
429 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
432 atari_dma_residual = 0;
433 atari_dma_active = 0;
435 if (atari_dma_orig_addr) {
436 /* If the dribble buffer was used on a read operation, copy the DMA-ed
437 * data to the original destination address.
439 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
440 HOSTDATA_DMALEN - atari_dma_residual);
441 atari_dma_orig_addr = NULL;
444 #endif /* REAL_DMA */
446 NCR5380_intr(irq, dummy);
452 static void atari_scsi_fetch_restbytes(void)
456 unsigned long phys_dst;
458 /* fetch rest bytes in the DMA register */
459 phys_dst = SCSI_DMA_READ_P(dma_addr);
462 /* there are 'nr' bytes left for the last long address
463 before the DMA pointer */
465 dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
467 /* The content of the DMA pointer is a physical address! */
468 dst = phys_to_virt(phys_dst);
469 dprintk(NDEBUG_DMA, " = virt addr %p\n", dst);
470 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
474 #endif /* REAL_DMA */
477 static int falcon_got_lock = 0;
478 static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait);
479 static int falcon_trying_lock = 0;
480 static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait);
481 static int falcon_dont_release = 0;
483 /* This function releases the lock on the DMA chip if there is no
484 * connected command and the disconnected queue is empty. On
485 * releasing, instances of falcon_get_lock are awoken, that put
486 * themselves to sleep for fairness. They can now try to get the lock
487 * again (but others waiting longer more probably will win).
490 static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
497 local_irq_save(flags);
499 if (falcon_got_lock && !hostdata->disconnected_queue &&
500 !hostdata->issue_queue && !hostdata->connected) {
502 if (falcon_dont_release) {
504 printk("WARNING: Lock release not allowed. Ignored\n");
506 local_irq_restore(flags);
511 wake_up(&falcon_fairness_wait);
514 local_irq_restore(flags);
517 /* This function manages the locking of the ST-DMA.
518 * If the DMA isn't locked already for SCSI, it tries to lock it by
519 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
520 * there are other drivers waiting for the chip, we do not issue the
521 * command immediately but wait on 'falcon_fairness_queue'. We will be
522 * waked up when the DMA is unlocked by some SCSI interrupt. After that
523 * we try to get the lock again.
524 * But we must be prepared that more than one instance of
525 * falcon_get_lock() is waiting on the fairness queue. They should not
526 * try all at once to call stdma_lock(), one is enough! For that, the
527 * first one sets 'falcon_trying_lock', others that see that variable
528 * set wait on the queue 'falcon_try_wait'.
529 * Complicated, complicated.... Sigh...
532 static void falcon_get_lock(void)
539 local_irq_save(flags);
541 wait_event_cmd(falcon_fairness_wait,
542 in_interrupt() || !falcon_got_lock || !stdma_others_waiting(),
543 local_irq_restore(flags),
544 local_irq_save(flags));
546 while (!falcon_got_lock) {
548 panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
549 if (!falcon_trying_lock) {
550 falcon_trying_lock = 1;
551 stdma_lock(scsi_falcon_intr, NULL);
553 falcon_trying_lock = 0;
554 wake_up(&falcon_try_wait);
556 wait_event_cmd(falcon_try_wait,
557 falcon_got_lock && !falcon_trying_lock,
558 local_irq_restore(flags),
559 local_irq_save(flags));
563 local_irq_restore(flags);
564 if (!falcon_got_lock)
565 panic("Falcon SCSI: someone stole the lock :-(\n");
569 static int __init atari_scsi_detect(struct scsi_host_template *host)
571 static int called = 0;
572 struct Scsi_Host *instance;
574 if (!MACH_IS_ATARI ||
575 (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) ||
579 host->proc_name = "Atari";
581 atari_scsi_reg_read = IS_A_TT() ? atari_scsi_tt_reg_read :
582 atari_scsi_falcon_reg_read;
583 atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write :
584 atari_scsi_falcon_reg_write;
586 /* setup variables */
588 (setup_can_queue > 0) ? setup_can_queue :
589 IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE;
591 (setup_cmd_per_lun > 0) ? setup_cmd_per_lun :
592 IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN;
593 /* Force sg_tablesize to 0 on a Falcon! */
595 !IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE :
596 (setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE;
598 if (setup_hostid >= 0)
599 host->this_id = setup_hostid;
601 /* use 7 as default */
603 /* Test if a host id is set in the NVRam */
604 if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
605 unsigned char b = nvram_read_byte( 14 );
606 /* Arbitration enabled? (for TOS) If yes, use configured host ID */
608 host->this_id = b & 7;
613 if (setup_use_tagged_queuing < 0)
614 setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING;
617 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
618 * memory block, since there's always ST-Ram in a Falcon), then allocate a
619 * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative
622 if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
623 !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
624 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
625 if (!atari_dma_buffer) {
626 printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM "
630 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
631 atari_dma_orig_addr = 0;
634 instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
635 if (instance == NULL) {
636 atari_stram_free(atari_dma_buffer);
637 atari_dma_buffer = 0;
640 atari_scsi_host = instance;
642 * Set irq to 0, to avoid that the mid-level code disables our interrupt
643 * during queue_command calls. This is completely unnecessary, and even
644 * worse causes bad problems on the Falcon, where the int is shared with
649 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
650 atari_scsi_reset_boot();
652 NCR5380_init(instance, 0);
656 /* This int is actually "pseudo-slow", i.e. it acts like a slow
657 * interrupt after having cleared the pending flag for the DMA
659 if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW,
660 "SCSI NCR5380", instance)) {
661 printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI);
662 scsi_unregister(atari_scsi_host);
663 atari_stram_free(atari_dma_buffer);
664 atari_dma_buffer = 0;
667 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
669 tt_scsi_dma.dma_ctrl = 0;
670 atari_dma_residual = 0;
672 if (MACH_IS_MEDUSA) {
673 /* While the read overruns (described by Drew Eckhardt in
674 * NCR5380.c) never happened on TTs, they do in fact on the Medusa
675 * (This was the cause why SCSI didn't work right for so long
676 * there.) Since handling the overruns slows down a bit, I turned
677 * the #ifdef's into a runtime condition.
679 * In principle it should be sufficient to do max. 1 byte with
680 * PIO, but there is another problem on the Medusa with the DMA
681 * rest data register. So 'atari_read_overruns' is currently set
682 * to 4 to avoid having transfers that aren't a multiple of 4. If
683 * the rest data bug is fixed, this can be lowered to 1.
685 atari_read_overruns = 4;
688 } else { /* ! IS_A_TT */
690 /* Nothing to do for the interrupt: the ST-DMA is initialized
691 * already by atari_init_INTS()
695 atari_dma_residual = 0;
696 atari_dma_active = 0;
697 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
702 printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d "
707 instance->host_no, instance->hostt->can_queue,
708 instance->hostt->cmd_per_lun,
709 instance->hostt->sg_tablesize,
711 setup_use_tagged_queuing ? "yes" : "no",
713 instance->hostt->this_id );
714 NCR5380_print_options(instance);
721 static int atari_scsi_release(struct Scsi_Host *sh)
724 free_irq(IRQ_TT_MFP_SCSI, sh);
725 if (atari_dma_buffer)
726 atari_stram_free(atari_dma_buffer);
732 static int __init atari_scsi_setup(char *str)
734 /* Format of atascsi parameter is:
735 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
736 * Defaults depend on TT or Falcon, hostid determined at run time.
737 * Negative values mean don't change.
741 get_options(str, ARRAY_SIZE(ints), ints);
744 printk("atari_scsi_setup: no arguments!\n");
750 /* no limits on this, just > 0 */
751 setup_can_queue = ints[1];
755 setup_cmd_per_lun = ints[2];
759 setup_sg_tablesize = ints[3];
760 /* Must be <= SG_ALL (255) */
761 if (setup_sg_tablesize > SG_ALL)
762 setup_sg_tablesize = SG_ALL;
766 /* Must be between 0 and 7 */
767 if (ints[4] >= 0 && ints[4] <= 7)
768 setup_hostid = ints[4];
769 else if (ints[4] > 7)
770 printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]);
775 setup_use_tagged_queuing = !!ints[5];
782 __setup("atascsi=", atari_scsi_setup);
786 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
787 static void __init atari_scsi_reset_boot(void)
792 * Do a SCSI reset to clean up the bus during initialization. No messing
793 * with the queues, interrupts, or locks necessary here.
796 printk("Atari SCSI: resetting the SCSI bus...");
799 NCR5380_write(TARGET_COMMAND_REG,
800 PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
803 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
804 /* The min. reset hold time is 25us, so 40us should be enough */
806 /* reset RST and interrupt */
807 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
808 NCR5380_read(RESET_PARITY_INTERRUPT_REG);
810 end = jiffies + AFTER_RESET_DELAY;
811 while (time_before(jiffies, end))
819 static const char *atari_scsi_info(struct Scsi_Host *host)
821 /* atari_scsi_detect() is verbose enough... */
822 static const char string[] = "Atari native SCSI";
827 #if defined(REAL_DMA)
829 static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
830 void *data, unsigned long count,
833 unsigned long addr = virt_to_phys(data);
835 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
836 "dir = %d\n", instance->host_no, data, addr, count, dir);
838 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
839 /* If we have a non-DMAable address on a Falcon, use the dribble
840 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
841 * handler to copy data from the dribble buffer to the originally
845 memcpy(atari_dma_buffer, data, count);
847 atari_dma_orig_addr = data;
848 addr = atari_dma_phys_buffer;
851 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
853 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
854 * it to the peripheral. (Must be done before DMA setup, since at least
855 * the ST-DMA begins to fill internal buffers right after setup. For
856 * reads, invalidate any cache, may be altered after DMA without CPU
859 * ++roman: For the Medusa, there's no need at all for that cache stuff,
860 * because the hardware does bus snooping (fine!).
862 dma_cache_maintenance(addr, count, dir);
865 printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
868 tt_scsi_dma.dma_ctrl = dir;
869 SCSI_DMA_WRITE_P(dma_addr, addr);
870 SCSI_DMA_WRITE_P(dma_cnt, count);
871 tt_scsi_dma.dma_ctrl = dir | 2;
872 } else { /* ! IS_A_TT */
875 SCSI_DMA_SETADR(addr);
877 /* toggle direction bit to clear FIFO and set DMA direction */
879 st_dma.dma_mode_status = 0x90 | dir;
880 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
881 st_dma.dma_mode_status = 0x90 | dir;
883 /* On writes, round up the transfer length to the next multiple of 512
884 * (see also comment at atari_dma_xfer_len()). */
885 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
887 st_dma.dma_mode_status = 0x10 | dir;
889 /* need not restore value of dir, only boolean value is tested */
890 atari_dma_active = 1;
897 static long atari_scsi_dma_residual(struct Scsi_Host *instance)
899 return atari_dma_residual;
903 #define CMD_SURELY_BLOCK_MODE 0
904 #define CMD_SURELY_BYTE_MODE 1
905 #define CMD_MODE_UNKNOWN 2
907 static int falcon_classify_cmd(Scsi_Cmnd *cmd)
909 unsigned char opcode = cmd->cmnd[0];
911 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
912 opcode == READ_BUFFER)
913 return CMD_SURELY_BYTE_MODE;
914 else if (opcode == READ_6 || opcode == READ_10 ||
915 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
916 opcode == RECOVER_BUFFERED_DATA) {
917 /* In case of a sequential-access target (tape), special care is
918 * needed here: The transfer is block-mode only if the 'fixed' bit is
920 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
921 return CMD_SURELY_BYTE_MODE;
923 return CMD_SURELY_BLOCK_MODE;
925 return CMD_MODE_UNKNOWN;
929 /* This function calculates the number of bytes that can be transferred via
930 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
931 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
932 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
933 * possible on the Falcon, since that would require to program the DMA for
934 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
935 * the overrun problem, so this question is academic :-)
938 static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
939 Scsi_Cmnd *cmd, int write_flag)
941 unsigned long possible_len, limit;
944 /* TT SCSI DMA can transfer arbitrary #bytes */
947 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
948 * 255*512 bytes, but this should be enough)
950 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
951 * that return a number of bytes which cannot be known beforehand. In this
952 * case, the given transfer length is an "allocation length". Now it
953 * can happen that this allocation length is a multiple of 512 bytes and
954 * the DMA is used. But if not n*512 bytes really arrive, some input data
955 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
956 * between commands that do block transfers and those that do byte
957 * transfers. But this isn't easy... there are lots of vendor specific
958 * commands, and the user can issue any command via the
959 * SCSI_IOCTL_SEND_COMMAND.
961 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
962 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
963 * and 3), the thing to do is obvious: allow any number of blocks via DMA
964 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
965 * the transfer (allocation) length is < 1024, hoping that no cmd. not
966 * explicitly known as byte mode have such big allocation lengths...
967 * BTW, all the discussion above applies only to reads. DMA writes are
968 * unproblematic anyways, since the targets aborts the transfer after
969 * receiving a sufficient number of bytes.
971 * Another point: If the transfer is from/to an non-ST-RAM address, we
972 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
976 /* Write operation can always use the DMA, but the transfer size must
977 * be rounded up to the next multiple of 512 (atari_dma_setup() does
980 possible_len = wanted_len;
982 /* Read operations: if the wanted transfer length is not a multiple of
983 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
984 * (no interrupt on DMA finished!)
986 if (wanted_len & 0x1ff)
989 /* Now classify the command (see above) and decide whether it is
990 * allowed to do DMA at all */
991 switch (falcon_classify_cmd(cmd)) {
992 case CMD_SURELY_BLOCK_MODE:
993 possible_len = wanted_len;
995 case CMD_SURELY_BYTE_MODE:
996 possible_len = 0; /* DMA prohibited */
998 case CMD_MODE_UNKNOWN:
1000 /* For unknown commands assume block transfers if the transfer
1001 * size/allocation length is >= 1024 */
1002 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
1008 /* Last step: apply the hard limit on DMA transfers */
1009 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
1010 STRAM_BUFFER_SIZE : 255*512;
1011 if (possible_len > limit)
1012 possible_len = limit;
1014 if (possible_len != wanted_len)
1015 dprintk(NDEBUG_DMA, "Sorry, must cut DMA transfer size to %ld bytes "
1016 "instead of %ld\n", possible_len, wanted_len);
1018 return possible_len;
1022 #endif /* REAL_DMA */
1025 /* NCR5380 register access functions
1027 * There are separate functions for TT and Falcon, because the access
1028 * methods are quite different. The calling macros NCR5380_read and
1029 * NCR5380_write call these functions via function pointers.
1032 static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
1034 return tt_scsi_regp[reg * 2];
1037 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
1039 tt_scsi_regp[reg * 2] = value;
1042 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
1044 dma_wd.dma_mode_status= (u_short)(0x88 + reg);
1045 return (u_char)dma_wd.fdc_acces_seccount;
1048 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
1050 dma_wd.dma_mode_status = (u_short)(0x88 + reg);
1051 dma_wd.fdc_acces_seccount = (u_short)value;
1055 #include "atari_NCR5380.c"
1057 static int atari_scsi_bus_reset(struct scsi_cmnd *cmd)
1060 struct NCR5380_hostdata *hostdata = shost_priv(cmd->device->host);
1062 /* For doing the reset, SCSI interrupts must be disabled first,
1063 * since the 5380 raises its IRQ line while _RST is active and we
1064 * can't disable interrupts completely, since we need the timer.
1066 /* And abort a maybe active DMA transfer */
1068 atari_turnoff_irq(IRQ_TT_MFP_SCSI);
1070 tt_scsi_dma.dma_ctrl = 0;
1073 atari_turnoff_irq(IRQ_MFP_FSCSI);
1075 st_dma.dma_mode_status = 0x90;
1076 atari_dma_active = 0;
1077 atari_dma_orig_addr = NULL;
1081 rv = NCR5380_bus_reset(cmd);
1084 atari_turnon_irq(IRQ_TT_MFP_SCSI);
1086 atari_turnon_irq(IRQ_MFP_FSCSI);
1089 falcon_release_lock_if_possible(hostdata);
1094 static struct scsi_host_template driver_template = {
1095 .show_info = atari_scsi_show_info,
1096 .name = "Atari native SCSI",
1097 .detect = atari_scsi_detect,
1098 .release = atari_scsi_release,
1099 .info = atari_scsi_info,
1100 .queuecommand = atari_scsi_queue_command,
1101 .eh_abort_handler = atari_scsi_abort,
1102 .eh_bus_reset_handler = atari_scsi_bus_reset,
1103 .can_queue = 0, /* initialized at run-time */
1104 .this_id = 0, /* initialized at run-time */
1105 .sg_tablesize = 0, /* initialized at run-time */
1106 .cmd_per_lun = 0, /* initialized at run-time */
1107 .use_clustering = DISABLE_CLUSTERING
1111 #include "scsi_module.c"
1113 MODULE_LICENSE("GPL");