1 /* 2 * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port 3 * 4 * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> 5 * 6 * Loosely based on the work of Robert De Vries' team and added: 7 * - working real DMA 8 * - Falcon support (untested yet!) ++bjoern fixed and now it works 9 * - lots of extensions and bug fixes. 10 * 11 * This file is subject to the terms and conditions of the GNU General Public 12 * License. See the file COPYING in the main directory of this archive 13 * for more details. 14 * 15 */ 16 17 18 /**************************************************************************/ 19 /* */ 20 /* Notes for Falcon SCSI: */ 21 /* ---------------------- */ 22 /* */ 23 /* Since the Falcon SCSI uses the ST-DMA chip, that is shared among */ 24 /* several device drivers, locking and unlocking the access to this */ 25 /* chip is required. But locking is not possible from an interrupt, */ 26 /* since it puts the process to sleep if the lock is not available. */ 27 /* This prevents "late" locking of the DMA chip, i.e. locking it just */ 28 /* before using it, since in case of disconnection-reconnection */ 29 /* commands, the DMA is started from the reselection interrupt. */ 30 /* */ 31 /* Two possible schemes for ST-DMA-locking would be: */ 32 /* 1) The lock is taken for each command separately and disconnecting */ 33 /* is forbidden (i.e. can_queue = 1). */ 34 /* 2) The DMA chip is locked when the first command comes in and */ 35 /* released when the last command is finished and all queues are */ 36 /* empty. */ 37 /* The first alternative would result in bad performance, since the */ 38 /* interleaving of commands would not be used. The second is unfair to */ 39 /* other drivers using the ST-DMA, because the queues will seldom be */ 40 /* totally empty if there is a lot of disk traffic. */ 41 /* */ 42 /* For this reasons I decided to employ a more elaborate scheme: */ 43 /* - First, we give up the lock every time we can (for fairness), this */ 44 /* means every time a command finishes and there are no other commands */ 45 /* on the disconnected queue. */ 46 /* - If there are others waiting to lock the DMA chip, we stop */ 47 /* issuing commands, i.e. moving them onto the issue queue. */ 48 /* Because of that, the disconnected queue will run empty in a */ 49 /* while. Instead we go to sleep on a 'fairness_queue'. */ 50 /* - If the lock is released, all processes waiting on the fairness */ 51 /* queue will be woken. The first of them tries to re-lock the DMA, */ 52 /* the others wait for the first to finish this task. After that, */ 53 /* they can all run on and do their commands... */ 54 /* This sounds complicated (and it is it :-(), but it seems to be a */ 55 /* good compromise between fairness and performance: As long as no one */ 56 /* else wants to work with the ST-DMA chip, SCSI can go along as */ 57 /* usual. If now someone else comes, this behaviour is changed to a */ 58 /* "fairness mode": just already initiated commands are finished and */ 59 /* then the lock is released. The other one waiting will probably win */ 60 /* the race for locking the DMA, since it was waiting for longer. And */ 61 /* after it has finished, SCSI can go ahead again. Finally: I hope I */ 62 /* have not produced any deadlock possibilities! */ 63 /* */ 64 /**************************************************************************/ 65 66 67 #include <linux/module.h> 68 #include <linux/types.h> 69 #include <linux/blkdev.h> 70 #include <linux/interrupt.h> 71 #include <linux/init.h> 72 #include <linux/nvram.h> 73 #include <linux/bitops.h> 74 #include <linux/wait.h> 75 #include <linux/platform_device.h> 76 77 #include <asm/setup.h> 78 #include <asm/atarihw.h> 79 #include <asm/atariints.h> 80 #include <asm/atari_stdma.h> 81 #include <asm/atari_stram.h> 82 #include <asm/io.h> 83 84 #include <scsi/scsi_host.h> 85 86 /* Definitions for the core NCR5380 driver. */ 87 88 #define REAL_DMA 89 #define SUPPORT_TAGS 90 #define MAX_TAGS 32 91 #define DMA_MIN_SIZE 32 92 93 #define NCR5380_implementation_fields /* none */ 94 95 #define NCR5380_read(reg) atari_scsi_reg_read(reg) 96 #define NCR5380_write(reg, value) atari_scsi_reg_write(reg, value) 97 98 #define NCR5380_queue_command atari_scsi_queue_command 99 #define NCR5380_abort atari_scsi_abort 100 #define NCR5380_info atari_scsi_info 101 102 #define NCR5380_dma_read_setup(instance, data, count) \ 103 atari_scsi_dma_setup(instance, data, count, 0) 104 #define NCR5380_dma_write_setup(instance, data, count) \ 105 atari_scsi_dma_setup(instance, data, count, 1) 106 #define NCR5380_dma_residual(instance) \ 107 atari_scsi_dma_residual(instance) 108 #define NCR5380_dma_xfer_len(instance, cmd, phase) \ 109 atari_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & SR_IO)) 110 111 #define NCR5380_acquire_dma_irq(instance) falcon_get_lock(instance) 112 #define NCR5380_release_dma_irq(instance) falcon_release_lock() 113 114 #include "NCR5380.h" 115 116 117 #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI) 118 119 #define SCSI_DMA_WRITE_P(elt,val) \ 120 do { \ 121 unsigned long v = val; \ 122 tt_scsi_dma.elt##_lo = v & 0xff; \ 123 v >>= 8; \ 124 tt_scsi_dma.elt##_lmd = v & 0xff; \ 125 v >>= 8; \ 126 tt_scsi_dma.elt##_hmd = v & 0xff; \ 127 v >>= 8; \ 128 tt_scsi_dma.elt##_hi = v & 0xff; \ 129 } while(0) 130 131 #define SCSI_DMA_READ_P(elt) \ 132 (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \ 133 (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \ 134 (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \ 135 (unsigned long)tt_scsi_dma.elt##_lo) 136 137 138 static inline void SCSI_DMA_SETADR(unsigned long adr) 139 { 140 st_dma.dma_lo = (unsigned char)adr; 141 MFPDELAY(); 142 adr >>= 8; 143 st_dma.dma_md = (unsigned char)adr; 144 MFPDELAY(); 145 adr >>= 8; 146 st_dma.dma_hi = (unsigned char)adr; 147 MFPDELAY(); 148 } 149 150 static inline unsigned long SCSI_DMA_GETADR(void) 151 { 152 unsigned long adr; 153 adr = st_dma.dma_lo; 154 MFPDELAY(); 155 adr |= (st_dma.dma_md & 0xff) << 8; 156 MFPDELAY(); 157 adr |= (st_dma.dma_hi & 0xff) << 16; 158 MFPDELAY(); 159 return adr; 160 } 161 162 #ifdef REAL_DMA 163 static void atari_scsi_fetch_restbytes(void); 164 #endif 165 166 static unsigned char (*atari_scsi_reg_read)(unsigned char reg); 167 static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value); 168 169 #ifdef REAL_DMA 170 static unsigned long atari_dma_residual, atari_dma_startaddr; 171 static short atari_dma_active; 172 /* pointer to the dribble buffer */ 173 static char *atari_dma_buffer; 174 /* precalculated physical address of the dribble buffer */ 175 static unsigned long atari_dma_phys_buffer; 176 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */ 177 static char *atari_dma_orig_addr; 178 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use 179 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare 180 * cases where requests to physical contiguous buffers have been merged, this 181 * request is <= 4k (one page). So I don't think we have to split transfers 182 * just due to this buffer size... 183 */ 184 #define STRAM_BUFFER_SIZE (4096) 185 /* mask for address bits that can't be used with the ST-DMA */ 186 static unsigned long atari_dma_stram_mask; 187 #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0) 188 #endif 189 190 static int setup_can_queue = -1; 191 module_param(setup_can_queue, int, 0); 192 static int setup_cmd_per_lun = -1; 193 module_param(setup_cmd_per_lun, int, 0); 194 static int setup_sg_tablesize = -1; 195 module_param(setup_sg_tablesize, int, 0); 196 static int setup_use_tagged_queuing = -1; 197 module_param(setup_use_tagged_queuing, int, 0); 198 static int setup_hostid = -1; 199 module_param(setup_hostid, int, 0); 200 static int setup_toshiba_delay = -1; 201 module_param(setup_toshiba_delay, int, 0); 202 203 204 #if defined(REAL_DMA) 205 206 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat) 207 { 208 int i; 209 unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr; 210 211 if (dma_stat & 0x01) { 212 213 /* A bus error happens when DMA-ing from the last page of a 214 * physical memory chunk (DMA prefetch!), but that doesn't hurt. 215 * Check for this case: 216 */ 217 218 for (i = 0; i < m68k_num_memory; ++i) { 219 end_addr = m68k_memory[i].addr + m68k_memory[i].size; 220 if (end_addr <= addr && addr <= end_addr + 4) 221 return 1; 222 } 223 } 224 return 0; 225 } 226 227 228 #if 0 229 /* Dead code... wasn't called anyway :-) and causes some trouble, because at 230 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has 231 * to clear the DMA int pending bit before it allows other level 6 interrupts. 232 */ 233 static void scsi_dma_buserr(int irq, void *dummy) 234 { 235 unsigned char dma_stat = tt_scsi_dma.dma_ctrl; 236 237 /* Don't do anything if a NCR interrupt is pending. Probably it's just 238 * masked... */ 239 if (atari_irq_pending(IRQ_TT_MFP_SCSI)) 240 return; 241 242 printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n", 243 SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt)); 244 if (dma_stat & 0x80) { 245 if (!scsi_dma_is_ignored_buserr(dma_stat)) 246 printk("SCSI DMA bus error -- bad DMA programming!\n"); 247 } else { 248 /* Under normal circumstances we never should get to this point, 249 * since both interrupts are triggered simultaneously and the 5380 250 * int has higher priority. When this irq is handled, that DMA 251 * interrupt is cleared. So a warning message is printed here. 252 */ 253 printk("SCSI DMA intr ?? -- this shouldn't happen!\n"); 254 } 255 } 256 #endif 257 258 #endif 259 260 261 static irqreturn_t scsi_tt_intr(int irq, void *dev) 262 { 263 #ifdef REAL_DMA 264 struct Scsi_Host *instance = dev; 265 struct NCR5380_hostdata *hostdata = shost_priv(instance); 266 int dma_stat; 267 268 dma_stat = tt_scsi_dma.dma_ctrl; 269 270 dsprintk(NDEBUG_INTR, instance, "NCR5380 interrupt, DMA status = %02x\n", 271 dma_stat & 0xff); 272 273 /* Look if it was the DMA that has interrupted: First possibility 274 * is that a bus error occurred... 275 */ 276 if (dma_stat & 0x80) { 277 if (!scsi_dma_is_ignored_buserr(dma_stat)) { 278 printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n", 279 SCSI_DMA_READ_P(dma_addr)); 280 printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!"); 281 } 282 } 283 284 /* If the DMA is active but not finished, we have the case 285 * that some other 5380 interrupt occurred within the DMA transfer. 286 * This means we have residual bytes, if the desired end address 287 * is not yet reached. Maybe we have to fetch some bytes from the 288 * rest data register, too. The residual must be calculated from 289 * the address pointer, not the counter register, because only the 290 * addr reg counts bytes not yet written and pending in the rest 291 * data reg! 292 */ 293 if ((dma_stat & 0x02) && !(dma_stat & 0x40)) { 294 atari_dma_residual = hostdata->dma_len - 295 (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr); 296 297 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n", 298 atari_dma_residual); 299 300 if ((signed int)atari_dma_residual < 0) 301 atari_dma_residual = 0; 302 if ((dma_stat & 1) == 0) { 303 /* 304 * After read operations, we maybe have to 305 * transport some rest bytes 306 */ 307 atari_scsi_fetch_restbytes(); 308 } else { 309 /* 310 * There seems to be a nasty bug in some SCSI-DMA/NCR 311 * combinations: If a target disconnects while a write 312 * operation is going on, the address register of the 313 * DMA may be a few bytes farer than it actually read. 314 * This is probably due to DMA prefetching and a delay 315 * between DMA and NCR. Experiments showed that the 316 * dma_addr is 9 bytes to high, but this could vary. 317 * The problem is, that the residual is thus calculated 318 * wrong and the next transfer will start behind where 319 * it should. So we round up the residual to the next 320 * multiple of a sector size, if it isn't already a 321 * multiple and the originally expected transfer size 322 * was. The latter condition is there to ensure that 323 * the correction is taken only for "real" data 324 * transfers and not for, e.g., the parameters of some 325 * other command. These shouldn't disconnect anyway. 326 */ 327 if (atari_dma_residual & 0x1ff) { 328 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, " 329 "difference %ld bytes\n", 330 512 - (atari_dma_residual & 0x1ff)); 331 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff; 332 } 333 } 334 tt_scsi_dma.dma_ctrl = 0; 335 } 336 337 /* If the DMA is finished, fetch the rest bytes and turn it off */ 338 if (dma_stat & 0x40) { 339 atari_dma_residual = 0; 340 if ((dma_stat & 1) == 0) 341 atari_scsi_fetch_restbytes(); 342 tt_scsi_dma.dma_ctrl = 0; 343 } 344 345 #endif /* REAL_DMA */ 346 347 NCR5380_intr(irq, dev); 348 349 return IRQ_HANDLED; 350 } 351 352 353 static irqreturn_t scsi_falcon_intr(int irq, void *dev) 354 { 355 #ifdef REAL_DMA 356 struct Scsi_Host *instance = dev; 357 struct NCR5380_hostdata *hostdata = shost_priv(instance); 358 int dma_stat; 359 360 /* Turn off DMA and select sector counter register before 361 * accessing the status register (Atari recommendation!) 362 */ 363 st_dma.dma_mode_status = 0x90; 364 dma_stat = st_dma.dma_mode_status; 365 366 /* Bit 0 indicates some error in the DMA process... don't know 367 * what happened exactly (no further docu). 368 */ 369 if (!(dma_stat & 0x01)) { 370 /* DMA error */ 371 printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR()); 372 } 373 374 /* If the DMA was active, but now bit 1 is not clear, it is some 375 * other 5380 interrupt that finishes the DMA transfer. We have to 376 * calculate the number of residual bytes and give a warning if 377 * bytes are stuck in the ST-DMA fifo (there's no way to reach them!) 378 */ 379 if (atari_dma_active && (dma_stat & 0x02)) { 380 unsigned long transferred; 381 382 transferred = SCSI_DMA_GETADR() - atari_dma_startaddr; 383 /* The ST-DMA address is incremented in 2-byte steps, but the 384 * data are written only in 16-byte chunks. If the number of 385 * transferred bytes is not divisible by 16, the remainder is 386 * lost somewhere in outer space. 387 */ 388 if (transferred & 15) 389 printk(KERN_ERR "SCSI DMA error: %ld bytes lost in " 390 "ST-DMA fifo\n", transferred & 15); 391 392 atari_dma_residual = hostdata->dma_len - transferred; 393 dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n", 394 atari_dma_residual); 395 } else 396 atari_dma_residual = 0; 397 atari_dma_active = 0; 398 399 if (atari_dma_orig_addr) { 400 /* If the dribble buffer was used on a read operation, copy the DMA-ed 401 * data to the original destination address. 402 */ 403 memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr), 404 hostdata->dma_len - atari_dma_residual); 405 atari_dma_orig_addr = NULL; 406 } 407 408 #endif /* REAL_DMA */ 409 410 NCR5380_intr(irq, dev); 411 412 return IRQ_HANDLED; 413 } 414 415 416 #ifdef REAL_DMA 417 static void atari_scsi_fetch_restbytes(void) 418 { 419 int nr; 420 char *src, *dst; 421 unsigned long phys_dst; 422 423 /* fetch rest bytes in the DMA register */ 424 phys_dst = SCSI_DMA_READ_P(dma_addr); 425 nr = phys_dst & 3; 426 if (nr) { 427 /* there are 'nr' bytes left for the last long address 428 before the DMA pointer */ 429 phys_dst ^= nr; 430 dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx", 431 nr, phys_dst); 432 /* The content of the DMA pointer is a physical address! */ 433 dst = phys_to_virt(phys_dst); 434 dprintk(NDEBUG_DMA, " = virt addr %p\n", dst); 435 for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr) 436 *dst++ = *src++; 437 } 438 } 439 #endif /* REAL_DMA */ 440 441 442 /* This function releases the lock on the DMA chip if there is no 443 * connected command and the disconnected queue is empty. 444 */ 445 446 static void falcon_release_lock(void) 447 { 448 if (IS_A_TT()) 449 return; 450 451 if (stdma_is_locked_by(scsi_falcon_intr)) 452 stdma_release(); 453 } 454 455 /* This function manages the locking of the ST-DMA. 456 * If the DMA isn't locked already for SCSI, it tries to lock it by 457 * calling stdma_lock(). But if the DMA is locked by the SCSI code and 458 * there are other drivers waiting for the chip, we do not issue the 459 * command immediately but tell the SCSI mid-layer to defer. 460 */ 461 462 static int falcon_get_lock(struct Scsi_Host *instance) 463 { 464 if (IS_A_TT()) 465 return 1; 466 467 if (in_interrupt()) 468 return stdma_try_lock(scsi_falcon_intr, instance); 469 470 stdma_lock(scsi_falcon_intr, instance); 471 return 1; 472 } 473 474 #ifndef MODULE 475 static int __init atari_scsi_setup(char *str) 476 { 477 /* Format of atascsi parameter is: 478 * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> 479 * Defaults depend on TT or Falcon, determined at run time. 480 * Negative values mean don't change. 481 */ 482 int ints[8]; 483 484 get_options(str, ARRAY_SIZE(ints), ints); 485 486 if (ints[0] < 1) { 487 printk("atari_scsi_setup: no arguments!\n"); 488 return 0; 489 } 490 if (ints[0] >= 1) 491 setup_can_queue = ints[1]; 492 if (ints[0] >= 2) 493 setup_cmd_per_lun = ints[2]; 494 if (ints[0] >= 3) 495 setup_sg_tablesize = ints[3]; 496 if (ints[0] >= 4) 497 setup_hostid = ints[4]; 498 if (ints[0] >= 5) 499 setup_use_tagged_queuing = ints[5]; 500 /* ints[6] (use_pdma) is ignored */ 501 if (ints[0] >= 7) 502 setup_toshiba_delay = ints[7]; 503 504 return 1; 505 } 506 507 __setup("atascsi=", atari_scsi_setup); 508 #endif /* !MODULE */ 509 510 511 #if defined(REAL_DMA) 512 513 static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance, 514 void *data, unsigned long count, 515 int dir) 516 { 517 unsigned long addr = virt_to_phys(data); 518 519 dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, " 520 "dir = %d\n", instance->host_no, data, addr, count, dir); 521 522 if (!IS_A_TT() && !STRAM_ADDR(addr)) { 523 /* If we have a non-DMAable address on a Falcon, use the dribble 524 * buffer; 'orig_addr' != 0 in the read case tells the interrupt 525 * handler to copy data from the dribble buffer to the originally 526 * wanted address. 527 */ 528 if (dir) 529 memcpy(atari_dma_buffer, data, count); 530 else 531 atari_dma_orig_addr = data; 532 addr = atari_dma_phys_buffer; 533 } 534 535 atari_dma_startaddr = addr; /* Needed for calculating residual later. */ 536 537 /* Cache cleanup stuff: On writes, push any dirty cache out before sending 538 * it to the peripheral. (Must be done before DMA setup, since at least 539 * the ST-DMA begins to fill internal buffers right after setup. For 540 * reads, invalidate any cache, may be altered after DMA without CPU 541 * knowledge. 542 * 543 * ++roman: For the Medusa, there's no need at all for that cache stuff, 544 * because the hardware does bus snooping (fine!). 545 */ 546 dma_cache_maintenance(addr, count, dir); 547 548 if (count == 0) 549 printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n"); 550 551 if (IS_A_TT()) { 552 tt_scsi_dma.dma_ctrl = dir; 553 SCSI_DMA_WRITE_P(dma_addr, addr); 554 SCSI_DMA_WRITE_P(dma_cnt, count); 555 tt_scsi_dma.dma_ctrl = dir | 2; 556 } else { /* ! IS_A_TT */ 557 558 /* set address */ 559 SCSI_DMA_SETADR(addr); 560 561 /* toggle direction bit to clear FIFO and set DMA direction */ 562 dir <<= 8; 563 st_dma.dma_mode_status = 0x90 | dir; 564 st_dma.dma_mode_status = 0x90 | (dir ^ 0x100); 565 st_dma.dma_mode_status = 0x90 | dir; 566 udelay(40); 567 /* On writes, round up the transfer length to the next multiple of 512 568 * (see also comment at atari_dma_xfer_len()). */ 569 st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9; 570 udelay(40); 571 st_dma.dma_mode_status = 0x10 | dir; 572 udelay(40); 573 /* need not restore value of dir, only boolean value is tested */ 574 atari_dma_active = 1; 575 } 576 577 return count; 578 } 579 580 581 static long atari_scsi_dma_residual(struct Scsi_Host *instance) 582 { 583 return atari_dma_residual; 584 } 585 586 587 #define CMD_SURELY_BLOCK_MODE 0 588 #define CMD_SURELY_BYTE_MODE 1 589 #define CMD_MODE_UNKNOWN 2 590 591 static int falcon_classify_cmd(struct scsi_cmnd *cmd) 592 { 593 unsigned char opcode = cmd->cmnd[0]; 594 595 if (opcode == READ_DEFECT_DATA || opcode == READ_LONG || 596 opcode == READ_BUFFER) 597 return CMD_SURELY_BYTE_MODE; 598 else if (opcode == READ_6 || opcode == READ_10 || 599 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE || 600 opcode == RECOVER_BUFFERED_DATA) { 601 /* In case of a sequential-access target (tape), special care is 602 * needed here: The transfer is block-mode only if the 'fixed' bit is 603 * set! */ 604 if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1)) 605 return CMD_SURELY_BYTE_MODE; 606 else 607 return CMD_SURELY_BLOCK_MODE; 608 } else 609 return CMD_MODE_UNKNOWN; 610 } 611 612 613 /* This function calculates the number of bytes that can be transferred via 614 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the 615 * ST-DMA chip. There are only multiples of 512 bytes possible and max. 616 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not 617 * possible on the Falcon, since that would require to program the DMA for 618 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have 619 * the overrun problem, so this question is academic :-) 620 */ 621 622 static unsigned long atari_dma_xfer_len(unsigned long wanted_len, 623 struct scsi_cmnd *cmd, int write_flag) 624 { 625 unsigned long possible_len, limit; 626 627 if (IS_A_TT()) 628 /* TT SCSI DMA can transfer arbitrary #bytes */ 629 return wanted_len; 630 631 /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max. 632 * 255*512 bytes, but this should be enough) 633 * 634 * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands 635 * that return a number of bytes which cannot be known beforehand. In this 636 * case, the given transfer length is an "allocation length". Now it 637 * can happen that this allocation length is a multiple of 512 bytes and 638 * the DMA is used. But if not n*512 bytes really arrive, some input data 639 * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish 640 * between commands that do block transfers and those that do byte 641 * transfers. But this isn't easy... there are lots of vendor specific 642 * commands, and the user can issue any command via the 643 * SCSI_IOCTL_SEND_COMMAND. 644 * 645 * The solution: We classify SCSI commands in 1) surely block-mode cmd.s, 646 * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1) 647 * and 3), the thing to do is obvious: allow any number of blocks via DMA 648 * or none. In case 2), we apply some heuristic: Byte mode is assumed if 649 * the transfer (allocation) length is < 1024, hoping that no cmd. not 650 * explicitly known as byte mode have such big allocation lengths... 651 * BTW, all the discussion above applies only to reads. DMA writes are 652 * unproblematic anyways, since the targets aborts the transfer after 653 * receiving a sufficient number of bytes. 654 * 655 * Another point: If the transfer is from/to an non-ST-RAM address, we 656 * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes. 657 */ 658 659 if (write_flag) { 660 /* Write operation can always use the DMA, but the transfer size must 661 * be rounded up to the next multiple of 512 (atari_dma_setup() does 662 * this). 663 */ 664 possible_len = wanted_len; 665 } else { 666 /* Read operations: if the wanted transfer length is not a multiple of 667 * 512, we cannot use DMA, since the ST-DMA cannot split transfers 668 * (no interrupt on DMA finished!) 669 */ 670 if (wanted_len & 0x1ff) 671 possible_len = 0; 672 else { 673 /* Now classify the command (see above) and decide whether it is 674 * allowed to do DMA at all */ 675 switch (falcon_classify_cmd(cmd)) { 676 case CMD_SURELY_BLOCK_MODE: 677 possible_len = wanted_len; 678 break; 679 case CMD_SURELY_BYTE_MODE: 680 possible_len = 0; /* DMA prohibited */ 681 break; 682 case CMD_MODE_UNKNOWN: 683 default: 684 /* For unknown commands assume block transfers if the transfer 685 * size/allocation length is >= 1024 */ 686 possible_len = (wanted_len < 1024) ? 0 : wanted_len; 687 break; 688 } 689 } 690 } 691 692 /* Last step: apply the hard limit on DMA transfers */ 693 limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ? 694 STRAM_BUFFER_SIZE : 255*512; 695 if (possible_len > limit) 696 possible_len = limit; 697 698 if (possible_len != wanted_len) 699 dprintk(NDEBUG_DMA, "Sorry, must cut DMA transfer size to %ld bytes " 700 "instead of %ld\n", possible_len, wanted_len); 701 702 return possible_len; 703 } 704 705 706 #endif /* REAL_DMA */ 707 708 709 /* NCR5380 register access functions 710 * 711 * There are separate functions for TT and Falcon, because the access 712 * methods are quite different. The calling macros NCR5380_read and 713 * NCR5380_write call these functions via function pointers. 714 */ 715 716 static unsigned char atari_scsi_tt_reg_read(unsigned char reg) 717 { 718 return tt_scsi_regp[reg * 2]; 719 } 720 721 static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value) 722 { 723 tt_scsi_regp[reg * 2] = value; 724 } 725 726 static unsigned char atari_scsi_falcon_reg_read(unsigned char reg) 727 { 728 dma_wd.dma_mode_status= (u_short)(0x88 + reg); 729 return (u_char)dma_wd.fdc_acces_seccount; 730 } 731 732 static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value) 733 { 734 dma_wd.dma_mode_status = (u_short)(0x88 + reg); 735 dma_wd.fdc_acces_seccount = (u_short)value; 736 } 737 738 739 #include "atari_NCR5380.c" 740 741 static int atari_scsi_bus_reset(struct scsi_cmnd *cmd) 742 { 743 int rv; 744 unsigned long flags; 745 746 local_irq_save(flags); 747 748 #ifdef REAL_DMA 749 /* Abort a maybe active DMA transfer */ 750 if (IS_A_TT()) { 751 tt_scsi_dma.dma_ctrl = 0; 752 } else { 753 st_dma.dma_mode_status = 0x90; 754 atari_dma_active = 0; 755 atari_dma_orig_addr = NULL; 756 } 757 #endif 758 759 rv = NCR5380_bus_reset(cmd); 760 761 /* The 5380 raises its IRQ line while _RST is active but the ST DMA 762 * "lock" has been released so this interrupt may end up handled by 763 * floppy or IDE driver (if one of them holds the lock). The NCR5380 764 * interrupt flag has been cleared already. 765 */ 766 767 local_irq_restore(flags); 768 769 return rv; 770 } 771 772 #define DRV_MODULE_NAME "atari_scsi" 773 #define PFX DRV_MODULE_NAME ": " 774 775 static struct scsi_host_template atari_scsi_template = { 776 .module = THIS_MODULE, 777 .proc_name = DRV_MODULE_NAME, 778 .name = "Atari native SCSI", 779 .info = atari_scsi_info, 780 .queuecommand = atari_scsi_queue_command, 781 .eh_abort_handler = atari_scsi_abort, 782 .eh_bus_reset_handler = atari_scsi_bus_reset, 783 .this_id = 7, 784 .use_clustering = DISABLE_CLUSTERING, 785 .cmd_size = NCR5380_CMD_SIZE, 786 }; 787 788 static int __init atari_scsi_probe(struct platform_device *pdev) 789 { 790 struct Scsi_Host *instance; 791 int error; 792 struct resource *irq; 793 int host_flags = 0; 794 795 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 796 if (!irq) 797 return -ENODEV; 798 799 if (ATARIHW_PRESENT(TT_SCSI)) { 800 atari_scsi_reg_read = atari_scsi_tt_reg_read; 801 atari_scsi_reg_write = atari_scsi_tt_reg_write; 802 } else { 803 atari_scsi_reg_read = atari_scsi_falcon_reg_read; 804 atari_scsi_reg_write = atari_scsi_falcon_reg_write; 805 } 806 807 /* The values for CMD_PER_LUN and CAN_QUEUE are somehow arbitrary. 808 * Higher values should work, too; try it! 809 * (But cmd_per_lun costs memory!) 810 * 811 * But there seems to be a bug somewhere that requires CAN_QUEUE to be 812 * 2*CMD_PER_LUN. At least on a TT, no spurious timeouts seen since 813 * changed CMD_PER_LUN... 814 * 815 * Note: The Falcon currently uses 8/1 setting due to unsolved problems 816 * with cmd_per_lun != 1 817 */ 818 if (ATARIHW_PRESENT(TT_SCSI)) { 819 atari_scsi_template.can_queue = 16; 820 atari_scsi_template.cmd_per_lun = 8; 821 atari_scsi_template.sg_tablesize = SG_ALL; 822 } else { 823 atari_scsi_template.can_queue = 8; 824 atari_scsi_template.cmd_per_lun = 1; 825 atari_scsi_template.sg_tablesize = SG_NONE; 826 } 827 828 if (setup_can_queue > 0) 829 atari_scsi_template.can_queue = setup_can_queue; 830 831 if (setup_cmd_per_lun > 0) 832 atari_scsi_template.cmd_per_lun = setup_cmd_per_lun; 833 834 /* Leave sg_tablesize at 0 on a Falcon! */ 835 if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize >= 0) 836 atari_scsi_template.sg_tablesize = setup_sg_tablesize; 837 838 if (setup_hostid >= 0) { 839 atari_scsi_template.this_id = setup_hostid & 7; 840 } else { 841 /* Test if a host id is set in the NVRam */ 842 if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) { 843 unsigned char b = nvram_read_byte(16); 844 845 /* Arbitration enabled? (for TOS) 846 * If yes, use configured host ID 847 */ 848 if (b & 0x80) 849 atari_scsi_template.this_id = b & 7; 850 } 851 } 852 853 854 #ifdef REAL_DMA 855 /* If running on a Falcon and if there's TT-Ram (i.e., more than one 856 * memory block, since there's always ST-Ram in a Falcon), then 857 * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers 858 * from/to alternative Ram. 859 */ 860 if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) && 861 m68k_num_memory > 1) { 862 atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI"); 863 if (!atari_dma_buffer) { 864 pr_err(PFX "can't allocate ST-RAM double buffer\n"); 865 return -ENOMEM; 866 } 867 atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer); 868 atari_dma_orig_addr = 0; 869 } 870 #endif 871 872 instance = scsi_host_alloc(&atari_scsi_template, 873 sizeof(struct NCR5380_hostdata)); 874 if (!instance) { 875 error = -ENOMEM; 876 goto fail_alloc; 877 } 878 879 instance->irq = irq->start; 880 881 host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP; 882 #ifdef SUPPORT_TAGS 883 host_flags |= setup_use_tagged_queuing > 0 ? FLAG_TAGGED_QUEUING : 0; 884 #endif 885 host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0; 886 887 error = NCR5380_init(instance, host_flags); 888 if (error) 889 goto fail_init; 890 891 if (IS_A_TT()) { 892 error = request_irq(instance->irq, scsi_tt_intr, 0, 893 "NCR5380", instance); 894 if (error) { 895 pr_err(PFX "request irq %d failed, aborting\n", 896 instance->irq); 897 goto fail_irq; 898 } 899 tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */ 900 #ifdef REAL_DMA 901 tt_scsi_dma.dma_ctrl = 0; 902 atari_dma_residual = 0; 903 904 /* While the read overruns (described by Drew Eckhardt in 905 * NCR5380.c) never happened on TTs, they do in fact on the 906 * Medusa (This was the cause why SCSI didn't work right for 907 * so long there.) Since handling the overruns slows down 908 * a bit, I turned the #ifdef's into a runtime condition. 909 * 910 * In principle it should be sufficient to do max. 1 byte with 911 * PIO, but there is another problem on the Medusa with the DMA 912 * rest data register. So read_overruns is currently set 913 * to 4 to avoid having transfers that aren't a multiple of 4. 914 * If the rest data bug is fixed, this can be lowered to 1. 915 */ 916 if (MACH_IS_MEDUSA) { 917 struct NCR5380_hostdata *hostdata = 918 shost_priv(instance); 919 920 hostdata->read_overruns = 4; 921 } 922 #endif 923 } else { 924 /* Nothing to do for the interrupt: the ST-DMA is initialized 925 * already. 926 */ 927 #ifdef REAL_DMA 928 atari_dma_residual = 0; 929 atari_dma_active = 0; 930 atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 931 : 0xff000000); 932 #endif 933 } 934 935 NCR5380_maybe_reset_bus(instance); 936 937 error = scsi_add_host(instance, NULL); 938 if (error) 939 goto fail_host; 940 941 platform_set_drvdata(pdev, instance); 942 943 scsi_scan_host(instance); 944 return 0; 945 946 fail_host: 947 if (IS_A_TT()) 948 free_irq(instance->irq, instance); 949 fail_irq: 950 NCR5380_exit(instance); 951 fail_init: 952 scsi_host_put(instance); 953 fail_alloc: 954 if (atari_dma_buffer) 955 atari_stram_free(atari_dma_buffer); 956 return error; 957 } 958 959 static int __exit atari_scsi_remove(struct platform_device *pdev) 960 { 961 struct Scsi_Host *instance = platform_get_drvdata(pdev); 962 963 scsi_remove_host(instance); 964 if (IS_A_TT()) 965 free_irq(instance->irq, instance); 966 NCR5380_exit(instance); 967 scsi_host_put(instance); 968 if (atari_dma_buffer) 969 atari_stram_free(atari_dma_buffer); 970 return 0; 971 } 972 973 static struct platform_driver atari_scsi_driver = { 974 .remove = __exit_p(atari_scsi_remove), 975 .driver = { 976 .name = DRV_MODULE_NAME, 977 }, 978 }; 979 980 module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe); 981 982 MODULE_ALIAS("platform:" DRV_MODULE_NAME); 983 MODULE_LICENSE("GPL"); 984