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 /**************************************************************************/
67 #include <linux/module.h>
68 #include <linux/types.h>
69 #include <linux/delay.h>
70 #include <linux/blkdev.h>
71 #include <linux/interrupt.h>
72 #include <linux/init.h>
73 #include <linux/nvram.h>
74 #include <linux/bitops.h>
75 #include <linux/wait.h>
76 #include <linux/platform_device.h>
78 #include <asm/setup.h>
79 #include <asm/atarihw.h>
80 #include <asm/atariints.h>
81 #include <asm/atari_stdma.h>
82 #include <asm/atari_stram.h>
85 #include <scsi/scsi_host.h>
87 /* Definitions for the core NCR5380 driver. */
93 #define NCR5380_implementation_fields /* none */
95 #define NCR5380_read(reg) atari_scsi_reg_read(reg)
96 #define NCR5380_write(reg, value) atari_scsi_reg_write(reg, value)
98 #define NCR5380_queue_command atari_scsi_queue_command
99 #define NCR5380_abort atari_scsi_abort
100 #define NCR5380_show_info atari_scsi_show_info
101 #define NCR5380_info atari_scsi_info
103 #define NCR5380_dma_read_setup(instance, data, count) \
104 atari_scsi_dma_setup(instance, data, count, 0)
105 #define NCR5380_dma_write_setup(instance, data, count) \
106 atari_scsi_dma_setup(instance, data, count, 1)
107 #define NCR5380_dma_residual(instance) \
108 atari_scsi_dma_residual(instance)
109 #define NCR5380_dma_xfer_len(instance, cmd, phase) \
110 atari_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & SR_IO))
112 #define NCR5380_acquire_dma_irq(instance) falcon_get_lock()
113 #define NCR5380_release_dma_irq(instance) falcon_release_lock()
118 #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI)
120 #define SCSI_DMA_WRITE_P(elt,val) \
122 unsigned long v = val; \
123 tt_scsi_dma.elt##_lo = v & 0xff; \
125 tt_scsi_dma.elt##_lmd = v & 0xff; \
127 tt_scsi_dma.elt##_hmd = v & 0xff; \
129 tt_scsi_dma.elt##_hi = v & 0xff; \
132 #define SCSI_DMA_READ_P(elt) \
133 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \
134 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \
135 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \
136 (unsigned long)tt_scsi_dma.elt##_lo)
139 static inline void SCSI_DMA_SETADR(unsigned long adr)
141 st_dma.dma_lo = (unsigned char)adr;
144 st_dma.dma_md = (unsigned char)adr;
147 st_dma.dma_hi = (unsigned char)adr;
151 static inline unsigned long SCSI_DMA_GETADR(void)
156 adr |= (st_dma.dma_md & 0xff) << 8;
158 adr |= (st_dma.dma_hi & 0xff) << 16;
163 #define HOSTDATA_DMALEN (((struct NCR5380_hostdata *) \
164 (atari_scsi_host->hostdata))->dma_len)
166 /* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
167 * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
168 * need ten times the standard value... */
169 #ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
170 #define AFTER_RESET_DELAY (HZ/2)
172 #define AFTER_RESET_DELAY (5*HZ/2)
176 static void atari_scsi_fetch_restbytes(void);
179 static struct Scsi_Host *atari_scsi_host;
180 static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
181 static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
184 static unsigned long atari_dma_residual, atari_dma_startaddr;
185 static short atari_dma_active;
186 /* pointer to the dribble buffer */
187 static char *atari_dma_buffer;
188 /* precalculated physical address of the dribble buffer */
189 static unsigned long atari_dma_phys_buffer;
190 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */
191 static char *atari_dma_orig_addr;
192 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
193 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
194 * cases where requests to physical contiguous buffers have been merged, this
195 * request is <= 4k (one page). So I don't think we have to split transfers
196 * just due to this buffer size...
198 #define STRAM_BUFFER_SIZE (4096)
199 /* mask for address bits that can't be used with the ST-DMA */
200 static unsigned long atari_dma_stram_mask;
201 #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0)
204 static int setup_can_queue = -1;
205 module_param(setup_can_queue, int, 0);
206 static int setup_cmd_per_lun = -1;
207 module_param(setup_cmd_per_lun, int, 0);
208 static int setup_sg_tablesize = -1;
209 module_param(setup_sg_tablesize, int, 0);
211 static int setup_use_tagged_queuing = -1;
212 module_param(setup_use_tagged_queuing, int, 0);
214 static int setup_hostid = -1;
215 module_param(setup_hostid, int, 0);
218 #if defined(REAL_DMA)
220 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
223 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
225 if (dma_stat & 0x01) {
227 /* A bus error happens when DMA-ing from the last page of a
228 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
229 * Check for this case:
232 for (i = 0; i < m68k_num_memory; ++i) {
233 end_addr = m68k_memory[i].addr + m68k_memory[i].size;
234 if (end_addr <= addr && addr <= end_addr + 4)
243 /* Dead code... wasn't called anyway :-) and causes some trouble, because at
244 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
245 * to clear the DMA int pending bit before it allows other level 6 interrupts.
247 static void scsi_dma_buserr(int irq, void *dummy)
249 unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
251 /* Don't do anything if a NCR interrupt is pending. Probably it's just
253 if (atari_irq_pending(IRQ_TT_MFP_SCSI))
256 printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
257 SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
258 if (dma_stat & 0x80) {
259 if (!scsi_dma_is_ignored_buserr(dma_stat))
260 printk("SCSI DMA bus error -- bad DMA programming!\n");
262 /* Under normal circumstances we never should get to this point,
263 * since both interrupts are triggered simultaneously and the 5380
264 * int has higher priority. When this irq is handled, that DMA
265 * interrupt is cleared. So a warning message is printed here.
267 printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
275 static irqreturn_t scsi_tt_intr(int irq, void *dummy)
280 dma_stat = tt_scsi_dma.dma_ctrl;
282 dprintk(NDEBUG_INTR, "scsi%d: NCR5380 interrupt, DMA status = %02x\n",
283 atari_scsi_host->host_no, dma_stat & 0xff);
285 /* Look if it was the DMA that has interrupted: First possibility
286 * is that a bus error occurred...
288 if (dma_stat & 0x80) {
289 if (!scsi_dma_is_ignored_buserr(dma_stat)) {
290 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
291 SCSI_DMA_READ_P(dma_addr));
292 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
296 /* If the DMA is active but not finished, we have the case
297 * that some other 5380 interrupt occurred within the DMA transfer.
298 * This means we have residual bytes, if the desired end address
299 * is not yet reached. Maybe we have to fetch some bytes from the
300 * rest data register, too. The residual must be calculated from
301 * the address pointer, not the counter register, because only the
302 * addr reg counts bytes not yet written and pending in the rest
305 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
306 atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
308 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
311 if ((signed int)atari_dma_residual < 0)
312 atari_dma_residual = 0;
313 if ((dma_stat & 1) == 0) {
315 * After read operations, we maybe have to
316 * transport some rest bytes
318 atari_scsi_fetch_restbytes();
321 * There seems to be a nasty bug in some SCSI-DMA/NCR
322 * combinations: If a target disconnects while a write
323 * operation is going on, the address register of the
324 * DMA may be a few bytes farer than it actually read.
325 * This is probably due to DMA prefetching and a delay
326 * between DMA and NCR. Experiments showed that the
327 * dma_addr is 9 bytes to high, but this could vary.
328 * The problem is, that the residual is thus calculated
329 * wrong and the next transfer will start behind where
330 * it should. So we round up the residual to the next
331 * multiple of a sector size, if it isn't already a
332 * multiple and the originally expected transfer size
333 * was. The latter condition is there to ensure that
334 * the correction is taken only for "real" data
335 * transfers and not for, e.g., the parameters of some
336 * other command. These shouldn't disconnect anyway.
338 if (atari_dma_residual & 0x1ff) {
339 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, "
340 "difference %ld bytes\n",
341 512 - (atari_dma_residual & 0x1ff));
342 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
345 tt_scsi_dma.dma_ctrl = 0;
348 /* If the DMA is finished, fetch the rest bytes and turn it off */
349 if (dma_stat & 0x40) {
350 atari_dma_residual = 0;
351 if ((dma_stat & 1) == 0)
352 atari_scsi_fetch_restbytes();
353 tt_scsi_dma.dma_ctrl = 0;
356 #endif /* REAL_DMA */
358 NCR5380_intr(irq, dummy);
364 static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
369 /* Turn off DMA and select sector counter register before
370 * accessing the status register (Atari recommendation!)
372 st_dma.dma_mode_status = 0x90;
373 dma_stat = st_dma.dma_mode_status;
375 /* Bit 0 indicates some error in the DMA process... don't know
376 * what happened exactly (no further docu).
378 if (!(dma_stat & 0x01)) {
380 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
383 /* If the DMA was active, but now bit 1 is not clear, it is some
384 * other 5380 interrupt that finishes the DMA transfer. We have to
385 * calculate the number of residual bytes and give a warning if
386 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
388 if (atari_dma_active && (dma_stat & 0x02)) {
389 unsigned long transferred;
391 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
392 /* The ST-DMA address is incremented in 2-byte steps, but the
393 * data are written only in 16-byte chunks. If the number of
394 * transferred bytes is not divisible by 16, the remainder is
395 * lost somewhere in outer space.
397 if (transferred & 15)
398 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
399 "ST-DMA fifo\n", transferred & 15);
401 atari_dma_residual = HOSTDATA_DMALEN - transferred;
402 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
405 atari_dma_residual = 0;
406 atari_dma_active = 0;
408 if (atari_dma_orig_addr) {
409 /* If the dribble buffer was used on a read operation, copy the DMA-ed
410 * data to the original destination address.
412 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
413 HOSTDATA_DMALEN - atari_dma_residual);
414 atari_dma_orig_addr = NULL;
417 #endif /* REAL_DMA */
419 NCR5380_intr(irq, dummy);
425 static void atari_scsi_fetch_restbytes(void)
429 unsigned long phys_dst;
431 /* fetch rest bytes in the DMA register */
432 phys_dst = SCSI_DMA_READ_P(dma_addr);
435 /* there are 'nr' bytes left for the last long address
436 before the DMA pointer */
438 dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
440 /* The content of the DMA pointer is a physical address! */
441 dst = phys_to_virt(phys_dst);
442 dprintk(NDEBUG_DMA, " = virt addr %p\n", dst);
443 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
447 #endif /* REAL_DMA */
450 /* This function releases the lock on the DMA chip if there is no
451 * connected command and the disconnected queue is empty.
454 static void falcon_release_lock(void)
459 if (stdma_is_locked_by(scsi_falcon_intr))
463 /* This function manages the locking of the ST-DMA.
464 * If the DMA isn't locked already for SCSI, it tries to lock it by
465 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
466 * there are other drivers waiting for the chip, we do not issue the
467 * command immediately but tell the SCSI mid-layer to defer.
470 static int falcon_get_lock(void)
476 return stdma_try_lock(scsi_falcon_intr, NULL);
478 stdma_lock(scsi_falcon_intr, NULL);
483 static int __init atari_scsi_setup(char *str)
485 /* Format of atascsi parameter is:
486 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
487 * Defaults depend on TT or Falcon, determined at run time.
488 * Negative values mean don't change.
492 get_options(str, ARRAY_SIZE(ints), ints);
495 printk("atari_scsi_setup: no arguments!\n");
499 setup_can_queue = ints[1];
501 setup_cmd_per_lun = ints[2];
503 setup_sg_tablesize = ints[3];
505 setup_hostid = ints[4];
508 setup_use_tagged_queuing = ints[5];
514 __setup("atascsi=", atari_scsi_setup);
518 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
519 static void __init atari_scsi_reset_boot(void)
524 * Do a SCSI reset to clean up the bus during initialization. No messing
525 * with the queues, interrupts, or locks necessary here.
528 printk("Atari SCSI: resetting the SCSI bus...");
531 NCR5380_write(TARGET_COMMAND_REG,
532 PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
535 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
536 /* The min. reset hold time is 25us, so 40us should be enough */
538 /* reset RST and interrupt */
539 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
540 NCR5380_read(RESET_PARITY_INTERRUPT_REG);
542 end = jiffies + AFTER_RESET_DELAY;
543 while (time_before(jiffies, end))
550 #if defined(REAL_DMA)
552 static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
553 void *data, unsigned long count,
556 unsigned long addr = virt_to_phys(data);
558 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
559 "dir = %d\n", instance->host_no, data, addr, count, dir);
561 if (!IS_A_TT() && !STRAM_ADDR(addr)) {
562 /* If we have a non-DMAable address on a Falcon, use the dribble
563 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
564 * handler to copy data from the dribble buffer to the originally
568 memcpy(atari_dma_buffer, data, count);
570 atari_dma_orig_addr = data;
571 addr = atari_dma_phys_buffer;
574 atari_dma_startaddr = addr; /* Needed for calculating residual later. */
576 /* Cache cleanup stuff: On writes, push any dirty cache out before sending
577 * it to the peripheral. (Must be done before DMA setup, since at least
578 * the ST-DMA begins to fill internal buffers right after setup. For
579 * reads, invalidate any cache, may be altered after DMA without CPU
582 * ++roman: For the Medusa, there's no need at all for that cache stuff,
583 * because the hardware does bus snooping (fine!).
585 dma_cache_maintenance(addr, count, dir);
588 printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
591 tt_scsi_dma.dma_ctrl = dir;
592 SCSI_DMA_WRITE_P(dma_addr, addr);
593 SCSI_DMA_WRITE_P(dma_cnt, count);
594 tt_scsi_dma.dma_ctrl = dir | 2;
595 } else { /* ! IS_A_TT */
598 SCSI_DMA_SETADR(addr);
600 /* toggle direction bit to clear FIFO and set DMA direction */
602 st_dma.dma_mode_status = 0x90 | dir;
603 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
604 st_dma.dma_mode_status = 0x90 | dir;
606 /* On writes, round up the transfer length to the next multiple of 512
607 * (see also comment at atari_dma_xfer_len()). */
608 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
610 st_dma.dma_mode_status = 0x10 | dir;
612 /* need not restore value of dir, only boolean value is tested */
613 atari_dma_active = 1;
620 static long atari_scsi_dma_residual(struct Scsi_Host *instance)
622 return atari_dma_residual;
626 #define CMD_SURELY_BLOCK_MODE 0
627 #define CMD_SURELY_BYTE_MODE 1
628 #define CMD_MODE_UNKNOWN 2
630 static int falcon_classify_cmd(struct scsi_cmnd *cmd)
632 unsigned char opcode = cmd->cmnd[0];
634 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
635 opcode == READ_BUFFER)
636 return CMD_SURELY_BYTE_MODE;
637 else if (opcode == READ_6 || opcode == READ_10 ||
638 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
639 opcode == RECOVER_BUFFERED_DATA) {
640 /* In case of a sequential-access target (tape), special care is
641 * needed here: The transfer is block-mode only if the 'fixed' bit is
643 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
644 return CMD_SURELY_BYTE_MODE;
646 return CMD_SURELY_BLOCK_MODE;
648 return CMD_MODE_UNKNOWN;
652 /* This function calculates the number of bytes that can be transferred via
653 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
654 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
655 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
656 * possible on the Falcon, since that would require to program the DMA for
657 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
658 * the overrun problem, so this question is academic :-)
661 static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
662 struct scsi_cmnd *cmd, int write_flag)
664 unsigned long possible_len, limit;
667 /* TT SCSI DMA can transfer arbitrary #bytes */
670 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
671 * 255*512 bytes, but this should be enough)
673 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
674 * that return a number of bytes which cannot be known beforehand. In this
675 * case, the given transfer length is an "allocation length". Now it
676 * can happen that this allocation length is a multiple of 512 bytes and
677 * the DMA is used. But if not n*512 bytes really arrive, some input data
678 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
679 * between commands that do block transfers and those that do byte
680 * transfers. But this isn't easy... there are lots of vendor specific
681 * commands, and the user can issue any command via the
682 * SCSI_IOCTL_SEND_COMMAND.
684 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
685 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
686 * and 3), the thing to do is obvious: allow any number of blocks via DMA
687 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
688 * the transfer (allocation) length is < 1024, hoping that no cmd. not
689 * explicitly known as byte mode have such big allocation lengths...
690 * BTW, all the discussion above applies only to reads. DMA writes are
691 * unproblematic anyways, since the targets aborts the transfer after
692 * receiving a sufficient number of bytes.
694 * Another point: If the transfer is from/to an non-ST-RAM address, we
695 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
699 /* Write operation can always use the DMA, but the transfer size must
700 * be rounded up to the next multiple of 512 (atari_dma_setup() does
703 possible_len = wanted_len;
705 /* Read operations: if the wanted transfer length is not a multiple of
706 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
707 * (no interrupt on DMA finished!)
709 if (wanted_len & 0x1ff)
712 /* Now classify the command (see above) and decide whether it is
713 * allowed to do DMA at all */
714 switch (falcon_classify_cmd(cmd)) {
715 case CMD_SURELY_BLOCK_MODE:
716 possible_len = wanted_len;
718 case CMD_SURELY_BYTE_MODE:
719 possible_len = 0; /* DMA prohibited */
721 case CMD_MODE_UNKNOWN:
723 /* For unknown commands assume block transfers if the transfer
724 * size/allocation length is >= 1024 */
725 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
731 /* Last step: apply the hard limit on DMA transfers */
732 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
733 STRAM_BUFFER_SIZE : 255*512;
734 if (possible_len > limit)
735 possible_len = limit;
737 if (possible_len != wanted_len)
738 dprintk(NDEBUG_DMA, "Sorry, must cut DMA transfer size to %ld bytes "
739 "instead of %ld\n", possible_len, wanted_len);
745 #endif /* REAL_DMA */
748 /* NCR5380 register access functions
750 * There are separate functions for TT and Falcon, because the access
751 * methods are quite different. The calling macros NCR5380_read and
752 * NCR5380_write call these functions via function pointers.
755 static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
757 return tt_scsi_regp[reg * 2];
760 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
762 tt_scsi_regp[reg * 2] = value;
765 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
767 dma_wd.dma_mode_status= (u_short)(0x88 + reg);
768 return (u_char)dma_wd.fdc_acces_seccount;
771 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
773 dma_wd.dma_mode_status = (u_short)(0x88 + reg);
774 dma_wd.fdc_acces_seccount = (u_short)value;
778 #include "atari_NCR5380.c"
780 static int atari_scsi_bus_reset(struct scsi_cmnd *cmd)
785 local_irq_save(flags);
788 /* Abort a maybe active DMA transfer */
790 tt_scsi_dma.dma_ctrl = 0;
792 st_dma.dma_mode_status = 0x90;
793 atari_dma_active = 0;
794 atari_dma_orig_addr = NULL;
798 rv = NCR5380_bus_reset(cmd);
800 /* The 5380 raises its IRQ line while _RST is active but the ST DMA
801 * "lock" has been released so this interrupt may end up handled by
802 * floppy or IDE driver (if one of them holds the lock). The NCR5380
803 * interrupt flag has been cleared already.
806 local_irq_restore(flags);
811 #define DRV_MODULE_NAME "atari_scsi"
812 #define PFX DRV_MODULE_NAME ": "
814 static struct scsi_host_template atari_scsi_template = {
815 .module = THIS_MODULE,
816 .proc_name = DRV_MODULE_NAME,
817 .show_info = atari_scsi_show_info,
818 .name = "Atari native SCSI",
819 .info = atari_scsi_info,
820 .queuecommand = atari_scsi_queue_command,
821 .eh_abort_handler = atari_scsi_abort,
822 .eh_bus_reset_handler = atari_scsi_bus_reset,
824 .use_clustering = DISABLE_CLUSTERING
827 static int __init atari_scsi_probe(struct platform_device *pdev)
829 struct Scsi_Host *instance;
831 struct resource *irq;
834 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
838 if (ATARIHW_PRESENT(TT_SCSI)) {
839 atari_scsi_reg_read = atari_scsi_tt_reg_read;
840 atari_scsi_reg_write = atari_scsi_tt_reg_write;
842 atari_scsi_reg_read = atari_scsi_falcon_reg_read;
843 atari_scsi_reg_write = atari_scsi_falcon_reg_write;
846 /* The values for CMD_PER_LUN and CAN_QUEUE are somehow arbitrary.
847 * Higher values should work, too; try it!
848 * (But cmd_per_lun costs memory!)
850 * But there seems to be a bug somewhere that requires CAN_QUEUE to be
851 * 2*CMD_PER_LUN. At least on a TT, no spurious timeouts seen since
852 * changed CMD_PER_LUN...
854 * Note: The Falcon currently uses 8/1 setting due to unsolved problems
855 * with cmd_per_lun != 1
857 if (ATARIHW_PRESENT(TT_SCSI)) {
858 atari_scsi_template.can_queue = 16;
859 atari_scsi_template.cmd_per_lun = 8;
860 atari_scsi_template.sg_tablesize = SG_ALL;
862 atari_scsi_template.can_queue = 8;
863 atari_scsi_template.cmd_per_lun = 1;
864 atari_scsi_template.sg_tablesize = SG_NONE;
867 if (setup_can_queue > 0)
868 atari_scsi_template.can_queue = setup_can_queue;
870 if (setup_cmd_per_lun > 0)
871 atari_scsi_template.cmd_per_lun = setup_cmd_per_lun;
873 /* Leave sg_tablesize at 0 on a Falcon! */
874 if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize >= 0)
875 atari_scsi_template.sg_tablesize = setup_sg_tablesize;
877 if (setup_hostid >= 0) {
878 atari_scsi_template.this_id = setup_hostid & 7;
880 /* Test if a host id is set in the NVRam */
881 if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
882 unsigned char b = nvram_read_byte(14);
884 /* Arbitration enabled? (for TOS)
885 * If yes, use configured host ID
888 atari_scsi_template.this_id = b & 7;
893 if (setup_use_tagged_queuing < 0)
894 setup_use_tagged_queuing = 0;
898 /* If running on a Falcon and if there's TT-Ram (i.e., more than one
899 * memory block, since there's always ST-Ram in a Falcon), then
900 * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers
901 * from/to alternative Ram.
903 if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) &&
904 m68k_num_memory > 1) {
905 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
906 if (!atari_dma_buffer) {
907 pr_err(PFX "can't allocate ST-RAM double buffer\n");
910 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
911 atari_dma_orig_addr = 0;
915 instance = scsi_host_alloc(&atari_scsi_template,
916 sizeof(struct NCR5380_hostdata));
921 atari_scsi_host = instance;
923 #ifdef CONFIG_ATARI_SCSI_RESET_BOOT
924 atari_scsi_reset_boot();
927 instance->irq = irq->start;
929 host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
931 NCR5380_init(instance, host_flags);
934 error = request_irq(instance->irq, scsi_tt_intr, 0,
935 "NCR5380", instance);
937 pr_err(PFX "request irq %d failed, aborting\n",
941 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
943 tt_scsi_dma.dma_ctrl = 0;
944 atari_dma_residual = 0;
946 /* While the read overruns (described by Drew Eckhardt in
947 * NCR5380.c) never happened on TTs, they do in fact on the
948 * Medusa (This was the cause why SCSI didn't work right for
949 * so long there.) Since handling the overruns slows down
950 * a bit, I turned the #ifdef's into a runtime condition.
952 * In principle it should be sufficient to do max. 1 byte with
953 * PIO, but there is another problem on the Medusa with the DMA
954 * rest data register. So read_overruns is currently set
955 * to 4 to avoid having transfers that aren't a multiple of 4.
956 * If the rest data bug is fixed, this can be lowered to 1.
958 if (MACH_IS_MEDUSA) {
959 struct NCR5380_hostdata *hostdata =
960 shost_priv(instance);
962 hostdata->read_overruns = 4;
966 /* Nothing to do for the interrupt: the ST-DMA is initialized
970 atari_dma_residual = 0;
971 atari_dma_active = 0;
972 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
977 error = scsi_add_host(instance, NULL);
981 platform_set_drvdata(pdev, instance);
983 scsi_scan_host(instance);
988 free_irq(instance->irq, instance);
990 NCR5380_exit(instance);
991 scsi_host_put(instance);
993 if (atari_dma_buffer)
994 atari_stram_free(atari_dma_buffer);
998 static int __exit atari_scsi_remove(struct platform_device *pdev)
1000 struct Scsi_Host *instance = platform_get_drvdata(pdev);
1002 scsi_remove_host(instance);
1004 free_irq(instance->irq, instance);
1005 NCR5380_exit(instance);
1006 scsi_host_put(instance);
1007 if (atari_dma_buffer)
1008 atari_stram_free(atari_dma_buffer);
1012 static struct platform_driver atari_scsi_driver = {
1013 .remove = __exit_p(atari_scsi_remove),
1015 .name = DRV_MODULE_NAME,
1016 .owner = THIS_MODULE,
1020 module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
1022 MODULE_ALIAS("platform:" DRV_MODULE_NAME);
1023 MODULE_LICENSE("GPL");