1/*
   2 * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
   3 *
   4 * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
   5 *
   6 *   Loosely based on the work of Robert De Vries' team and added:
   7 *    - working real DMA
   8 *    - Falcon support (untested yet!)   ++bjoern fixed and now it works
   9 *    - lots of extensions and bug fixes.
  10 *
  11 * This file is subject to the terms and conditions of the GNU General Public
  12 * License.  See the file COPYING in the main directory of this archive
  13 * for more details.
  14 *
  15 */
  16
  17
  18/**************************************************************************/
  19/*                                                                        */
  20/* Notes for Falcon SCSI:                                                 */
  21/* ----------------------                                                 */
  22/*                                                                        */
  23/* Since the Falcon SCSI uses the ST-DMA chip, that is shared among       */
  24/* several device drivers, locking and unlocking the access to this       */
  25/* chip is required. But locking is not possible from an interrupt,       */
  26/* since it puts the process to sleep if the lock is not available.       */
  27/* This prevents "late" locking of the DMA chip, i.e. locking it just     */
  28/* before using it, since in case of disconnection-reconnection           */
  29/* commands, the DMA is started from the reselection interrupt.           */
  30/*                                                                        */
  31/* Two possible schemes for ST-DMA-locking would be:                      */
  32/*  1) The lock is taken for each command separately and disconnecting    */
  33/*     is forbidden (i.e. can_queue = 1).                                 */
  34/*  2) The DMA chip is locked when the first command comes in and         */
  35/*     released when the last command is finished and all queues are      */
  36/*     empty.                                                             */
  37/* The first alternative would result in bad performance, since the       */
  38/* interleaving of commands would not be used. The second is unfair to    */
  39/* other drivers using the ST-DMA, because the queues will seldom be      */
  40/* totally empty if there is a lot of disk traffic.                       */
  41/*                                                                        */
  42/* For this reasons I decided to employ a more elaborate scheme:          */
  43/*  - First, we give up the lock every time we can (for fairness), this    */
  44/*    means every time a command finishes and there are no other commands */
  45/*    on the disconnected queue.                                          */
  46/*  - If there are others waiting to lock the DMA chip, we stop           */
  47/*    issuing commands, i.e. moving them onto the issue queue.           */
  48/*    Because of that, the disconnected queue will run empty in a         */
  49/*    while. Instead we go to sleep on a 'fairness_queue'.                */
  50/*  - If the lock is released, all processes waiting on the fairness      */
  51/*    queue will be woken. The first of them tries to re-lock the DMA,     */
  52/*    the others wait for the first to finish this task. After that,      */
  53/*    they can all run on and do their commands...                        */
  54/* This sounds complicated (and it is it :-(), but it seems to be a       */
  55/* good compromise between fairness and performance: As long as no one     */
  56/* else wants to work with the ST-DMA chip, SCSI can go along as          */
  57/* usual. If now someone else comes, this behaviour is changed to a       */
  58/* "fairness mode": just already initiated commands are finished and      */
  59/* then the lock is released. The other one waiting will probably win     */
  60/* the race for locking the DMA, since it was waiting for longer. And     */
  61/* after it has finished, SCSI can go ahead again. Finally: I hope I      */
  62/* have not produced any deadlock possibilities!                          */
  63/*                                                                        */
  64/**************************************************************************/
  65
  66
  67
  68#include <linux/module.h>
  69
  70#define NDEBUG (0)
  71
  72#define NDEBUG_ABORT		0x00100000
  73#define NDEBUG_TAGS		0x00200000
  74#define NDEBUG_MERGING		0x00400000
  75
  76#define AUTOSENSE
  77/* For the Atari version, use only polled IO or REAL_DMA */
  78#define	REAL_DMA
  79/* Support tagged queuing? (on devices that are able to... :-) */
  80#define	SUPPORT_TAGS
  81#define	MAX_TAGS 32
  82
  83#include <linux/types.h>
  84#include <linux/stddef.h>
  85#include <linux/ctype.h>
  86#include <linux/delay.h>
  87#include <linux/mm.h>
  88#include <linux/blkdev.h>
  89#include <linux/interrupt.h>
  90#include <linux/init.h>
  91#include <linux/nvram.h>
  92#include <linux/bitops.h>
  93
  94#include <asm/setup.h>
  95#include <asm/atarihw.h>
  96#include <asm/atariints.h>
  97#include <asm/page.h>
  98#include <asm/pgtable.h>
  99#include <asm/irq.h>
 100#include <asm/traps.h>
 101
 102#include "scsi.h"
 103#include <scsi/scsi_host.h>
 104#include "atari_scsi.h"
 105#include "NCR5380.h"
 106#include <asm/atari_stdma.h>
 107#include <asm/atari_stram.h>
 108#include <asm/io.h>
 109
 110#include <linux/stat.h>
 111
 112#define	IS_A_TT()	ATARIHW_PRESENT(TT_SCSI)
 113
 114#define	SCSI_DMA_WRITE_P(elt,val)				\
 115	do {							\
 116		unsigned long v = val;				\
 117		tt_scsi_dma.elt##_lo = v & 0xff;		\
 118		v >>= 8;					\
 119		tt_scsi_dma.elt##_lmd = v & 0xff;		\
 120		v >>= 8;					\
 121		tt_scsi_dma.elt##_hmd = v & 0xff;		\
 122		v >>= 8;					\
 123		tt_scsi_dma.elt##_hi = v & 0xff;		\
 124	} while(0)
 125
 126#define	SCSI_DMA_READ_P(elt)					\
 127	(((((((unsigned long)tt_scsi_dma.elt##_hi << 8) |	\
 128	     (unsigned long)tt_scsi_dma.elt##_hmd) << 8) |	\
 129	   (unsigned long)tt_scsi_dma.elt##_lmd) << 8) |	\
 130	 (unsigned long)tt_scsi_dma.elt##_lo)
 131
 132
 133static inline void SCSI_DMA_SETADR(unsigned long adr)
 134{
 135	st_dma.dma_lo = (unsigned char)adr;
 136	MFPDELAY();
 137	adr >>= 8;
 138	st_dma.dma_md = (unsigned char)adr;
 139	MFPDELAY();
 140	adr >>= 8;
 141	st_dma.dma_hi = (unsigned char)adr;
 142	MFPDELAY();
 143}
 144
 145static inline unsigned long SCSI_DMA_GETADR(void)
 146{
 147	unsigned long adr;
 148	adr = st_dma.dma_lo;
 149	MFPDELAY();
 150	adr |= (st_dma.dma_md & 0xff) << 8;
 151	MFPDELAY();
 152	adr |= (st_dma.dma_hi & 0xff) << 16;
 153	MFPDELAY();
 154	return adr;
 155}
 156
 157static inline void ENABLE_IRQ(void)
 158{
 159	if (IS_A_TT())
 160		atari_enable_irq(IRQ_TT_MFP_SCSI);
 161	else
 162		atari_enable_irq(IRQ_MFP_FSCSI);
 163}
 164
 165static inline void DISABLE_IRQ(void)
 166{
 167	if (IS_A_TT())
 168		atari_disable_irq(IRQ_TT_MFP_SCSI);
 169	else
 170		atari_disable_irq(IRQ_MFP_FSCSI);
 171}
 172
 173
 174#define HOSTDATA_DMALEN		(((struct NCR5380_hostdata *) \
 175				(atari_scsi_host->hostdata))->dma_len)
 176
 177/* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
 178 * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
 179 * need ten times the standard value... */
 180#ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
 181#define	AFTER_RESET_DELAY	(HZ/2)
 182#else
 183#define	AFTER_RESET_DELAY	(5*HZ/2)
 184#endif
 185
 186/***************************** Prototypes *****************************/
 187
 188#ifdef REAL_DMA
 189static int scsi_dma_is_ignored_buserr(unsigned char dma_stat);
 190static void atari_scsi_fetch_restbytes(void);
 191static long atari_scsi_dma_residual(struct Scsi_Host *instance);
 192static int falcon_classify_cmd(Scsi_Cmnd *cmd);
 193static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
 194					Scsi_Cmnd *cmd, int write_flag);
 195#endif
 196static irqreturn_t scsi_tt_intr(int irq, void *dummy);
 197static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
 198static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
 199static void falcon_get_lock(void);
 200#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 201static void atari_scsi_reset_boot(void);
 202#endif
 203static unsigned char atari_scsi_tt_reg_read(unsigned char reg);
 204static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value);
 205static unsigned char atari_scsi_falcon_reg_read(unsigned char reg);
 206static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value);
 207
 208/************************* End of Prototypes **************************/
 209
 210
 211static struct Scsi_Host *atari_scsi_host;
 212static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
 213static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
 214
 215#ifdef REAL_DMA
 216static unsigned long	atari_dma_residual, atari_dma_startaddr;
 217static short		atari_dma_active;
 218/* pointer to the dribble buffer */
 219static char		*atari_dma_buffer;
 220/* precalculated physical address of the dribble buffer */
 221static unsigned long	atari_dma_phys_buffer;
 222/* != 0 tells the Falcon int handler to copy data from the dribble buffer */
 223static char		*atari_dma_orig_addr;
 224/* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
 225 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
 226 * cases where requests to physical contiguous buffers have been merged, this
 227 * request is <= 4k (one page). So I don't think we have to split transfers
 228 * just due to this buffer size...
 229 */
 230#define	STRAM_BUFFER_SIZE	(4096)
 231/* mask for address bits that can't be used with the ST-DMA */
 232static unsigned long	atari_dma_stram_mask;
 233#define STRAM_ADDR(a)	(((a) & atari_dma_stram_mask) == 0)
 234/* number of bytes to cut from a transfer to handle NCR overruns */
 235static int atari_read_overruns;
 236#endif
 237
 238static int setup_can_queue = -1;
 239module_param(setup_can_queue, int, 0);
 240static int setup_cmd_per_lun = -1;
 241module_param(setup_cmd_per_lun, int, 0);
 242static int setup_sg_tablesize = -1;
 243module_param(setup_sg_tablesize, int, 0);
 244#ifdef SUPPORT_TAGS
 245static int setup_use_tagged_queuing = -1;
 246module_param(setup_use_tagged_queuing, int, 0);
 247#endif
 248static int setup_hostid = -1;
 249module_param(setup_hostid, int, 0);
 250
 251
 252#if defined(REAL_DMA)
 253
 254static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
 255{
 256	int i;
 257	unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
 258
 259	if (dma_stat & 0x01) {
 260
 261		/* A bus error happens when DMA-ing from the last page of a
 262		 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
 263		 * Check for this case:
 264		 */
 265
 266		for (i = 0; i < m68k_num_memory; ++i) {
 267			end_addr = m68k_memory[i].addr + m68k_memory[i].size;
 268			if (end_addr <= addr && addr <= end_addr + 4)
 269				return 1;
 270		}
 271	}
 272	return 0;
 273}
 274
 275
 276#if 0
 277/* Dead code... wasn't called anyway :-) and causes some trouble, because at
 278 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
 279 * to clear the DMA int pending bit before it allows other level 6 interrupts.
 280 */
 281static void scsi_dma_buserr(int irq, void *dummy)
 282{
 283	unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
 284
 285	/* Don't do anything if a NCR interrupt is pending. Probably it's just
 286	 * masked... */
 287	if (atari_irq_pending(IRQ_TT_MFP_SCSI))
 288		return;
 289
 290	printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
 291	       SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
 292	if (dma_stat & 0x80) {
 293		if (!scsi_dma_is_ignored_buserr(dma_stat))
 294			printk("SCSI DMA bus error -- bad DMA programming!\n");
 295	} else {
 296		/* Under normal circumstances we never should get to this point,
 297		 * since both interrupts are triggered simultaneously and the 5380
 298		 * int has higher priority. When this irq is handled, that DMA
 299		 * interrupt is cleared. So a warning message is printed here.
 300		 */
 301		printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
 302	}
 303}
 304#endif
 305
 306#endif
 307
 308
 309static irqreturn_t scsi_tt_intr(int irq, void *dummy)
 310{
 311#ifdef REAL_DMA
 312	int dma_stat;
 313
 314	dma_stat = tt_scsi_dma.dma_ctrl;
 315
 316	INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n",
 317		   atari_scsi_host->host_no, dma_stat & 0xff);
 318
 319	/* Look if it was the DMA that has interrupted: First possibility
 320	 * is that a bus error occurred...
 321	 */
 322	if (dma_stat & 0x80) {
 323		if (!scsi_dma_is_ignored_buserr(dma_stat)) {
 324			printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
 325			       SCSI_DMA_READ_P(dma_addr));
 326			printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
 327		}
 328	}
 329
 330	/* If the DMA is active but not finished, we have the case
 331	 * that some other 5380 interrupt occurred within the DMA transfer.
 332	 * This means we have residual bytes, if the desired end address
 333	 * is not yet reached. Maybe we have to fetch some bytes from the
 334	 * rest data register, too. The residual must be calculated from
 335	 * the address pointer, not the counter register, because only the
 336	 * addr reg counts bytes not yet written and pending in the rest
 337	 * data reg!
 338	 */
 339	if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
 340		atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
 341
 342		DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
 343			   atari_dma_residual);
 344
 345		if ((signed int)atari_dma_residual < 0)
 346			atari_dma_residual = 0;
 347		if ((dma_stat & 1) == 0) {
 348			/*
 349			 * After read operations, we maybe have to
 350			 * transport some rest bytes
 351			 */
 352			atari_scsi_fetch_restbytes();
 353		} else {
 354			/*
 355			 * There seems to be a nasty bug in some SCSI-DMA/NCR
 356			 * combinations: If a target disconnects while a write
 357			 * operation is going on, the address register of the
 358			 * DMA may be a few bytes farer than it actually read.
 359			 * This is probably due to DMA prefetching and a delay
 360			 * between DMA and NCR.  Experiments showed that the
 361			 * dma_addr is 9 bytes to high, but this could vary.
 362			 * The problem is, that the residual is thus calculated
 363			 * wrong and the next transfer will start behind where
 364			 * it should.  So we round up the residual to the next
 365			 * multiple of a sector size, if it isn't already a
 366			 * multiple and the originally expected transfer size
 367			 * was.  The latter condition is there to ensure that
 368			 * the correction is taken only for "real" data
 369			 * transfers and not for, e.g., the parameters of some
 370			 * other command.  These shouldn't disconnect anyway.
 371			 */
 372			if (atari_dma_residual & 0x1ff) {
 373				DMA_PRINTK("SCSI DMA: DMA bug corrected, "
 374					   "difference %ld bytes\n",
 375					   512 - (atari_dma_residual & 0x1ff));
 376				atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
 377			}
 378		}
 379		tt_scsi_dma.dma_ctrl = 0;
 380	}
 381
 382	/* If the DMA is finished, fetch the rest bytes and turn it off */
 383	if (dma_stat & 0x40) {
 384		atari_dma_residual = 0;
 385		if ((dma_stat & 1) == 0)
 386			atari_scsi_fetch_restbytes();
 387		tt_scsi_dma.dma_ctrl = 0;
 388	}
 389
 390#endif /* REAL_DMA */
 391
 392	NCR5380_intr(irq, dummy);
 393
 394#if 0
 395	/* To be sure the int is not masked */
 396	atari_enable_irq(IRQ_TT_MFP_SCSI);
 397#endif
 398	return IRQ_HANDLED;
 399}
 400
 401
 402static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
 403{
 404#ifdef REAL_DMA
 405	int dma_stat;
 406
 407	/* Turn off DMA and select sector counter register before
 408	 * accessing the status register (Atari recommendation!)
 409	 */
 410	st_dma.dma_mode_status = 0x90;
 411	dma_stat = st_dma.dma_mode_status;
 412
 413	/* Bit 0 indicates some error in the DMA process... don't know
 414	 * what happened exactly (no further docu).
 415	 */
 416	if (!(dma_stat & 0x01)) {
 417		/* DMA error */
 418		printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
 419	}
 420
 421	/* If the DMA was active, but now bit 1 is not clear, it is some
 422	 * other 5380 interrupt that finishes the DMA transfer. We have to
 423	 * calculate the number of residual bytes and give a warning if
 424	 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
 425	 */
 426	if (atari_dma_active && (dma_stat & 0x02)) {
 427		unsigned long transferred;
 428
 429		transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
 430		/* The ST-DMA address is incremented in 2-byte steps, but the
 431		 * data are written only in 16-byte chunks. If the number of
 432		 * transferred bytes is not divisible by 16, the remainder is
 433		 * lost somewhere in outer space.
 434		 */
 435		if (transferred & 15)
 436			printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
 437			       "ST-DMA fifo\n", transferred & 15);
 438
 439		atari_dma_residual = HOSTDATA_DMALEN - transferred;
 440		DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
 441			   atari_dma_residual);
 442	} else
 443		atari_dma_residual = 0;
 444	atari_dma_active = 0;
 445
 446	if (atari_dma_orig_addr) {
 447		/* If the dribble buffer was used on a read operation, copy the DMA-ed
 448		 * data to the original destination address.
 449		 */
 450		memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
 451		       HOSTDATA_DMALEN - atari_dma_residual);
 452		atari_dma_orig_addr = NULL;
 453	}
 454
 455#endif /* REAL_DMA */
 456
 457	NCR5380_intr(irq, dummy);
 458	return IRQ_HANDLED;
 459}
 460
 461
 462#ifdef REAL_DMA
 463static void atari_scsi_fetch_restbytes(void)
 464{
 465	int nr;
 466	char *src, *dst;
 467	unsigned long phys_dst;
 468
 469	/* fetch rest bytes in the DMA register */
 470	phys_dst = SCSI_DMA_READ_P(dma_addr);
 471	nr = phys_dst & 3;
 472	if (nr) {
 473		/* there are 'nr' bytes left for the last long address
 474		   before the DMA pointer */
 475		phys_dst ^= nr;
 476		DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
 477			   nr, phys_dst);
 478		/* The content of the DMA pointer is a physical address!  */
 479		dst = phys_to_virt(phys_dst);
 480		DMA_PRINTK(" = virt addr %p\n", dst);
 481		for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
 482			*dst++ = *src++;
 483	}
 484}
 485#endif /* REAL_DMA */
 486
 487
 488static int falcon_got_lock = 0;
 489static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait);
 490static int falcon_trying_lock = 0;
 491static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait);
 492static int falcon_dont_release = 0;
 493
 494/* This function releases the lock on the DMA chip if there is no
 495 * connected command and the disconnected queue is empty. On
 496 * releasing, instances of falcon_get_lock are awoken, that put
 497 * themselves to sleep for fairness. They can now try to get the lock
 498 * again (but others waiting longer more probably will win).
 499 */
 500
 501static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
 502{
 503	unsigned long flags;
 504
 505	if (IS_A_TT())
 506		return;
 507
 508	local_irq_save(flags);
 509
 510	if (falcon_got_lock && !hostdata->disconnected_queue &&
 511	    !hostdata->issue_queue && !hostdata->connected) {
 512
 513		if (falcon_dont_release) {
 514#if 0
 515			printk("WARNING: Lock release not allowed. Ignored\n");
 516#endif
 517			local_irq_restore(flags);
 518			return;
 519		}
 520		falcon_got_lock = 0;
 521		stdma_release();
 522		wake_up(&falcon_fairness_wait);
 523	}
 524
 525	local_irq_restore(flags);
 526}
 527
 528/* This function manages the locking of the ST-DMA.
 529 * If the DMA isn't locked already for SCSI, it tries to lock it by
 530 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
 531 * there are other drivers waiting for the chip, we do not issue the
 532 * command immediately but wait on 'falcon_fairness_queue'. We will be
 533 * waked up when the DMA is unlocked by some SCSI interrupt. After that
 534 * we try to get the lock again.
 535 * But we must be prepared that more than one instance of
 536 * falcon_get_lock() is waiting on the fairness queue. They should not
 537 * try all at once to call stdma_lock(), one is enough! For that, the
 538 * first one sets 'falcon_trying_lock', others that see that variable
 539 * set wait on the queue 'falcon_try_wait'.
 540 * Complicated, complicated.... Sigh...
 541 */
 542
 543static void falcon_get_lock(void)
 544{
 545	unsigned long flags;
 546
 547	if (IS_A_TT())
 548		return;
 549
 550	local_irq_save(flags);
 551
 552	while (!in_irq() && falcon_got_lock && stdma_others_waiting())
 553		sleep_on(&falcon_fairness_wait);
 554
 555	while (!falcon_got_lock) {
 556		if (in_irq())
 557			panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
 558		if (!falcon_trying_lock) {
 559			falcon_trying_lock = 1;
 560			stdma_lock(scsi_falcon_intr, NULL);
 561			falcon_got_lock = 1;
 562			falcon_trying_lock = 0;
 563			wake_up(&falcon_try_wait);
 564		} else {
 565			sleep_on(&falcon_try_wait);
 566		}
 567	}
 568
 569	local_irq_restore(flags);
 570	if (!falcon_got_lock)
 571		panic("Falcon SCSI: someone stole the lock :-(\n");
 572}
 573
 574
 575int __init atari_scsi_detect(struct scsi_host_template *host)
 576{
 577	static int called = 0;
 578	struct Scsi_Host *instance;
 579
 580	if (!MACH_IS_ATARI ||
 581	    (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) ||
 582	    called)
 583		return 0;
 584
 585	host->proc_name = "Atari";
 586
 587	atari_scsi_reg_read  = IS_A_TT() ? atari_scsi_tt_reg_read :
 588					   atari_scsi_falcon_reg_read;
 589	atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write :
 590					   atari_scsi_falcon_reg_write;
 591
 592	/* setup variables */
 593	host->can_queue =
 594		(setup_can_queue > 0) ? setup_can_queue :
 595		IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE;
 596	host->cmd_per_lun =
 597		(setup_cmd_per_lun > 0) ? setup_cmd_per_lun :
 598		IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN;
 599	/* Force sg_tablesize to 0 on a Falcon! */
 600	host->sg_tablesize =
 601		!IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE :
 602		(setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE;
 603
 604	if (setup_hostid >= 0)
 605		host->this_id = setup_hostid;
 606	else {
 607		/* use 7 as default */
 608		host->this_id = 7;
 609		/* Test if a host id is set in the NVRam */
 610		if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
 611			unsigned char b = nvram_read_byte( 14 );
 612			/* Arbitration enabled? (for TOS) If yes, use configured host ID */
 613			if (b & 0x80)
 614				host->this_id = b & 7;
 615		}
 616	}
 617
 618#ifdef SUPPORT_TAGS
 619	if (setup_use_tagged_queuing < 0)
 620		setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING;
 621#endif
 622#ifdef REAL_DMA
 623	/* If running on a Falcon and if there's TT-Ram (i.e., more than one
 624	 * memory block, since there's always ST-Ram in a Falcon), then allocate a
 625	 * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative
 626	 * Ram.
 627	 */
 628	if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
 629	    !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
 630		atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
 631		if (!atari_dma_buffer) {
 632			printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM "
 633					"double buffer\n");
 634			return 0;
 635		}
 636		atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
 637		atari_dma_orig_addr = 0;
 638	}
 639#endif
 640	instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
 641	if (instance == NULL) {
 642		atari_stram_free(atari_dma_buffer);
 643		atari_dma_buffer = 0;
 644		return 0;
 645	}
 646	atari_scsi_host = instance;
 647	/*
 648	 * Set irq to 0, to avoid that the mid-level code disables our interrupt
 649	 * during queue_command calls. This is completely unnecessary, and even
 650	 * worse causes bad problems on the Falcon, where the int is shared with
 651	 * IDE and floppy!
 652	 */
 653       instance->irq = 0;
 654
 655#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 656	atari_scsi_reset_boot();
 657#endif
 658	NCR5380_init(instance, 0);
 659
 660	if (IS_A_TT()) {
 661
 662		/* This int is actually "pseudo-slow", i.e. it acts like a slow
 663		 * interrupt after having cleared the pending flag for the DMA
 664		 * interrupt. */
 665		if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW,
 666				 "SCSI NCR5380", instance)) {
 667			printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI);
 668			scsi_unregister(atari_scsi_host);
 669			atari_stram_free(atari_dma_buffer);
 670			atari_dma_buffer = 0;
 671			return 0;
 672		}
 673		tt_mfp.active_edge |= 0x80;		/* SCSI int on L->H */
 674#ifdef REAL_DMA
 675		tt_scsi_dma.dma_ctrl = 0;
 676		atari_dma_residual = 0;
 677
 678		if (MACH_IS_MEDUSA) {
 679			/* While the read overruns (described by Drew Eckhardt in
 680			 * NCR5380.c) never happened on TTs, they do in fact on the Medusa
 681			 * (This was the cause why SCSI didn't work right for so long
 682			 * there.) Since handling the overruns slows down a bit, I turned
 683			 * the #ifdef's into a runtime condition.
 684			 *
 685			 * In principle it should be sufficient to do max. 1 byte with
 686			 * PIO, but there is another problem on the Medusa with the DMA
 687			 * rest data register. So 'atari_read_overruns' is currently set
 688			 * to 4 to avoid having transfers that aren't a multiple of 4. If
 689			 * the rest data bug is fixed, this can be lowered to 1.
 690			 */
 691			atari_read_overruns = 4;
 692		}
 693#endif /*REAL_DMA*/
 694	} else { /* ! IS_A_TT */
 695
 696		/* Nothing to do for the interrupt: the ST-DMA is initialized
 697		 * already by atari_init_INTS()
 698		 */
 699
 700#ifdef REAL_DMA
 701		atari_dma_residual = 0;
 702		atari_dma_active = 0;
 703		atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
 704					: 0xff000000);
 705#endif
 706	}
 707
 708	printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d "
 709#ifdef SUPPORT_TAGS
 710			"TAGGED-QUEUING=%s "
 711#endif
 712			"HOSTID=%d",
 713			instance->host_no, instance->hostt->can_queue,
 714			instance->hostt->cmd_per_lun,
 715			instance->hostt->sg_tablesize,
 716#ifdef SUPPORT_TAGS
 717			setup_use_tagged_queuing ? "yes" : "no",
 718#endif
 719			instance->hostt->this_id );
 720	NCR5380_print_options(instance);
 721	printk("\n");
 722
 723	called = 1;
 724	return 1;
 725}
 726
 727int atari_scsi_release(struct Scsi_Host *sh)
 728{
 729	if (IS_A_TT())
 730		free_irq(IRQ_TT_MFP_SCSI, sh);
 731	if (atari_dma_buffer)
 732		atari_stram_free(atari_dma_buffer);
 733	NCR5380_exit(sh);
 734	return 1;
 735}
 736
 737void __init atari_scsi_setup(char *str, int *ints)
 
 738{
 739	/* Format of atascsi parameter is:
 740	 *   atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 741	 * Defaults depend on TT or Falcon, hostid determined at run time.
 742	 * Negative values mean don't change.
 743	 */
 
 
 
 744
 745	if (ints[0] < 1) {
 746		printk("atari_scsi_setup: no arguments!\n");
 747		return;
 748	}
 749
 750	if (ints[0] >= 1) {
 751		if (ints[1] > 0)
 752			/* no limits on this, just > 0 */
 753			setup_can_queue = ints[1];
 754	}
 755	if (ints[0] >= 2) {
 756		if (ints[2] > 0)
 757			setup_cmd_per_lun = ints[2];
 758	}
 759	if (ints[0] >= 3) {
 760		if (ints[3] >= 0) {
 761			setup_sg_tablesize = ints[3];
 762			/* Must be <= SG_ALL (255) */
 763			if (setup_sg_tablesize > SG_ALL)
 764				setup_sg_tablesize = SG_ALL;
 765		}
 766	}
 767	if (ints[0] >= 4) {
 768		/* Must be between 0 and 7 */
 769		if (ints[4] >= 0 && ints[4] <= 7)
 770			setup_hostid = ints[4];
 771		else if (ints[4] > 7)
 772			printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]);
 773	}
 774#ifdef SUPPORT_TAGS
 775	if (ints[0] >= 5) {
 776		if (ints[5] >= 0)
 777			setup_use_tagged_queuing = !!ints[5];
 778	}
 779#endif
 
 
 780}
 781
 782int atari_scsi_bus_reset(Scsi_Cmnd *cmd)
 
 
 
 783{
 784	int rv;
 785	struct NCR5380_hostdata *hostdata =
 786		(struct NCR5380_hostdata *)cmd->device->host->hostdata;
 787
 788	/* For doing the reset, SCSI interrupts must be disabled first,
 789	 * since the 5380 raises its IRQ line while _RST is active and we
 790	 * can't disable interrupts completely, since we need the timer.
 791	 */
 792	/* And abort a maybe active DMA transfer */
 793	if (IS_A_TT()) {
 794		atari_turnoff_irq(IRQ_TT_MFP_SCSI);
 795#ifdef REAL_DMA
 796		tt_scsi_dma.dma_ctrl = 0;
 797#endif /* REAL_DMA */
 798	} else {
 799		atari_turnoff_irq(IRQ_MFP_FSCSI);
 800#ifdef REAL_DMA
 801		st_dma.dma_mode_status = 0x90;
 802		atari_dma_active = 0;
 803		atari_dma_orig_addr = NULL;
 804#endif /* REAL_DMA */
 805	}
 806
 807	rv = NCR5380_bus_reset(cmd);
 808
 809	/* Re-enable ints */
 810	if (IS_A_TT()) {
 811		atari_turnon_irq(IRQ_TT_MFP_SCSI);
 812	} else {
 813		atari_turnon_irq(IRQ_MFP_FSCSI);
 814	}
 815	if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS)
 816		falcon_release_lock_if_possible(hostdata);
 817
 818	return rv;
 819}
 820
 821
 822#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 823static void __init atari_scsi_reset_boot(void)
 824{
 825	unsigned long end;
 826
 827	/*
 828	 * Do a SCSI reset to clean up the bus during initialization. No messing
 829	 * with the queues, interrupts, or locks necessary here.
 830	 */
 831
 832	printk("Atari SCSI: resetting the SCSI bus...");
 833
 834	/* get in phase */
 835	NCR5380_write(TARGET_COMMAND_REG,
 836		      PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
 837
 838	/* assert RST */
 839	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
 840	/* The min. reset hold time is 25us, so 40us should be enough */
 841	udelay(50);
 842	/* reset RST and interrupt */
 843	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 844	NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 845
 846	end = jiffies + AFTER_RESET_DELAY;
 847	while (time_before(jiffies, end))
 848		barrier();
 849
 850	printk(" done\n");
 851}
 852#endif
 853
 854
 855const char *atari_scsi_info(struct Scsi_Host *host)
 856{
 857	/* atari_scsi_detect() is verbose enough... */
 858	static const char string[] = "Atari native SCSI";
 859	return string;
 860}
 861
 862
 863#if defined(REAL_DMA)
 864
 865unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance, void *data,
 866				   unsigned long count, int dir)
 
 867{
 868	unsigned long addr = virt_to_phys(data);
 869
 870	DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
 871		   "dir = %d\n", instance->host_no, data, addr, count, dir);
 872
 873	if (!IS_A_TT() && !STRAM_ADDR(addr)) {
 874		/* If we have a non-DMAable address on a Falcon, use the dribble
 875		 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
 876		 * handler to copy data from the dribble buffer to the originally
 877		 * wanted address.
 878		 */
 879		if (dir)
 880			memcpy(atari_dma_buffer, data, count);
 881		else
 882			atari_dma_orig_addr = data;
 883		addr = atari_dma_phys_buffer;
 884	}
 885
 886	atari_dma_startaddr = addr;	/* Needed for calculating residual later. */
 887
 888	/* Cache cleanup stuff: On writes, push any dirty cache out before sending
 889	 * it to the peripheral. (Must be done before DMA setup, since at least
 890	 * the ST-DMA begins to fill internal buffers right after setup. For
 891	 * reads, invalidate any cache, may be altered after DMA without CPU
 892	 * knowledge.
 893	 *
 894	 * ++roman: For the Medusa, there's no need at all for that cache stuff,
 895	 * because the hardware does bus snooping (fine!).
 896	 */
 897	dma_cache_maintenance(addr, count, dir);
 898
 899	if (count == 0)
 900		printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
 901
 902	if (IS_A_TT()) {
 903		tt_scsi_dma.dma_ctrl = dir;
 904		SCSI_DMA_WRITE_P(dma_addr, addr);
 905		SCSI_DMA_WRITE_P(dma_cnt, count);
 906		tt_scsi_dma.dma_ctrl = dir | 2;
 907	} else { /* ! IS_A_TT */
 908
 909		/* set address */
 910		SCSI_DMA_SETADR(addr);
 911
 912		/* toggle direction bit to clear FIFO and set DMA direction */
 913		dir <<= 8;
 914		st_dma.dma_mode_status = 0x90 | dir;
 915		st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
 916		st_dma.dma_mode_status = 0x90 | dir;
 917		udelay(40);
 918		/* On writes, round up the transfer length to the next multiple of 512
 919		 * (see also comment at atari_dma_xfer_len()). */
 920		st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
 921		udelay(40);
 922		st_dma.dma_mode_status = 0x10 | dir;
 923		udelay(40);
 924		/* need not restore value of dir, only boolean value is tested */
 925		atari_dma_active = 1;
 926	}
 927
 928	return count;
 929}
 930
 931
 932static long atari_scsi_dma_residual(struct Scsi_Host *instance)
 933{
 934	return atari_dma_residual;
 935}
 936
 937
 938#define	CMD_SURELY_BLOCK_MODE	0
 939#define	CMD_SURELY_BYTE_MODE	1
 940#define	CMD_MODE_UNKNOWN		2
 941
 942static int falcon_classify_cmd(Scsi_Cmnd *cmd)
 943{
 944	unsigned char opcode = cmd->cmnd[0];
 945
 946	if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
 947	    opcode == READ_BUFFER)
 948		return CMD_SURELY_BYTE_MODE;
 949	else if (opcode == READ_6 || opcode == READ_10 ||
 950		 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
 951		 opcode == RECOVER_BUFFERED_DATA) {
 952		/* In case of a sequential-access target (tape), special care is
 953		 * needed here: The transfer is block-mode only if the 'fixed' bit is
 954		 * set! */
 955		if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
 956			return CMD_SURELY_BYTE_MODE;
 957		else
 958			return CMD_SURELY_BLOCK_MODE;
 959	} else
 960		return CMD_MODE_UNKNOWN;
 961}
 962
 963
 964/* This function calculates the number of bytes that can be transferred via
 965 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
 966 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
 967 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
 968 * possible on the Falcon, since that would require to program the DMA for
 969 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
 970 * the overrun problem, so this question is academic :-)
 971 */
 972
 973static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
 974					Scsi_Cmnd *cmd, int write_flag)
 975{
 976	unsigned long	possible_len, limit;
 977
 978	if (IS_A_TT())
 979		/* TT SCSI DMA can transfer arbitrary #bytes */
 980		return wanted_len;
 981
 982	/* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
 983	 * 255*512 bytes, but this should be enough)
 984	 *
 985	 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
 986	 * that return a number of bytes which cannot be known beforehand. In this
 987	 * case, the given transfer length is an "allocation length". Now it
 988	 * can happen that this allocation length is a multiple of 512 bytes and
 989	 * the DMA is used. But if not n*512 bytes really arrive, some input data
 990	 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
 991	 * between commands that do block transfers and those that do byte
 992	 * transfers. But this isn't easy... there are lots of vendor specific
 993	 * commands, and the user can issue any command via the
 994	 * SCSI_IOCTL_SEND_COMMAND.
 995	 *
 996	 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
 997	 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
 998	 * and 3), the thing to do is obvious: allow any number of blocks via DMA
 999	 * or none. In case 2), we apply some heuristic: Byte mode is assumed if
1000	 * the transfer (allocation) length is < 1024, hoping that no cmd. not
1001	 * explicitly known as byte mode have such big allocation lengths...
1002	 * BTW, all the discussion above applies only to reads. DMA writes are
1003	 * unproblematic anyways, since the targets aborts the transfer after
1004	 * receiving a sufficient number of bytes.
1005	 *
1006	 * Another point: If the transfer is from/to an non-ST-RAM address, we
1007	 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
1008	 */
1009
1010	if (write_flag) {
1011		/* Write operation can always use the DMA, but the transfer size must
1012		 * be rounded up to the next multiple of 512 (atari_dma_setup() does
1013		 * this).
1014		 */
1015		possible_len = wanted_len;
1016	} else {
1017		/* Read operations: if the wanted transfer length is not a multiple of
1018		 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
1019		 * (no interrupt on DMA finished!)
1020		 */
1021		if (wanted_len & 0x1ff)
1022			possible_len = 0;
1023		else {
1024			/* Now classify the command (see above) and decide whether it is
1025			 * allowed to do DMA at all */
1026			switch (falcon_classify_cmd(cmd)) {
1027			case CMD_SURELY_BLOCK_MODE:
1028				possible_len = wanted_len;
1029				break;
1030			case CMD_SURELY_BYTE_MODE:
1031				possible_len = 0; /* DMA prohibited */
1032				break;
1033			case CMD_MODE_UNKNOWN:
1034			default:
1035				/* For unknown commands assume block transfers if the transfer
1036				 * size/allocation length is >= 1024 */
1037				possible_len = (wanted_len < 1024) ? 0 : wanted_len;
1038				break;
1039			}
1040		}
1041	}
1042
1043	/* Last step: apply the hard limit on DMA transfers */
1044	limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
1045		    STRAM_BUFFER_SIZE : 255*512;
1046	if (possible_len > limit)
1047		possible_len = limit;
1048
1049	if (possible_len != wanted_len)
1050		DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes "
1051			   "instead of %ld\n", possible_len, wanted_len);
1052
1053	return possible_len;
1054}
1055
1056
1057#endif	/* REAL_DMA */
1058
1059
1060/* NCR5380 register access functions
1061 *
1062 * There are separate functions for TT and Falcon, because the access
1063 * methods are quite different. The calling macros NCR5380_read and
1064 * NCR5380_write call these functions via function pointers.
1065 */
1066
1067static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
1068{
1069	return tt_scsi_regp[reg * 2];
1070}
1071
1072static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
1073{
1074	tt_scsi_regp[reg * 2] = value;
1075}
1076
1077static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
1078{
1079	dma_wd.dma_mode_status= (u_short)(0x88 + reg);
1080	return (u_char)dma_wd.fdc_acces_seccount;
1081}
1082
1083static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
1084{
1085	dma_wd.dma_mode_status = (u_short)(0x88 + reg);
1086	dma_wd.fdc_acces_seccount = (u_short)value;
1087}
1088
1089
1090#include "atari_NCR5380.c"
1091
1092static struct scsi_host_template driver_template = {
1093	.proc_info		= atari_scsi_proc_info,
1094	.name			= "Atari native SCSI",
1095	.detect			= atari_scsi_detect,
1096	.release		= atari_scsi_release,
1097	.info			= atari_scsi_info,
1098	.queuecommand		= atari_scsi_queue_command,
1099	.eh_abort_handler	= atari_scsi_abort,
1100	.eh_bus_reset_handler	= atari_scsi_bus_reset,
1101	.can_queue		= 0, /* initialized at run-time */
1102	.this_id		= 0, /* initialized at run-time */
1103	.sg_tablesize		= 0, /* initialized at run-time */
1104	.cmd_per_lun		= 0, /* initialized at run-time */
1105	.use_clustering		= DISABLE_CLUSTERING
1106};
1107
1108
1109#include "scsi_module.c"
1110
1111MODULE_LICENSE("GPL");