1 | /* |
2 | * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port |
3 | * |
4 | * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> |
5 | * |
6 | * Loosely based on the work of Robert De Vries' team and added: |
7 | * - working real DMA |
8 | * - Falcon support (untested yet!) ++bjoern fixed and now it works |
9 | * - lots of extensions and bug fixes. |
10 | * |
11 | * This file is subject to the terms and conditions of the GNU General Public |
12 | * License. See the file COPYING in the main directory of this archive |
13 | * for more details. |
14 | * |
15 | */ |
16 | |
17 | /* |
18 | * Notes for Falcon SCSI DMA |
19 | * |
20 | * The 5380 device is one of several that all share the DMA chip. Hence |
21 | * "locking" and "unlocking" access to this chip is required. |
22 | * |
23 | * Two possible schemes for ST DMA acquisition by atari_scsi are: |
24 | * 1) The lock is taken for each command separately (i.e. can_queue == 1). |
25 | * 2) The lock is taken when the first command arrives and released |
26 | * when the last command is finished (i.e. can_queue > 1). |
27 | * |
28 | * The first alternative limits SCSI bus utilization, since interleaving |
29 | * commands is not possible. The second gives better performance but is |
30 | * unfair to other drivers needing to use the ST DMA chip. In order to |
31 | * allow the IDE and floppy drivers equal access to the ST DMA chip |
32 | * the default is can_queue == 1. |
33 | */ |
34 | |
35 | #include <linux/module.h> |
36 | #include <linux/types.h> |
37 | #include <linux/blkdev.h> |
38 | #include <linux/interrupt.h> |
39 | #include <linux/init.h> |
40 | #include <linux/nvram.h> |
41 | #include <linux/bitops.h> |
42 | #include <linux/wait.h> |
43 | #include <linux/platform_device.h> |
44 | |
45 | #include <asm/setup.h> |
46 | #include <asm/atarihw.h> |
47 | #include <asm/atariints.h> |
48 | #include <asm/atari_stdma.h> |
49 | #include <asm/atari_stram.h> |
50 | #include <asm/io.h> |
51 | |
52 | #include <scsi/scsi_host.h> |
53 | |
54 | #define DMA_MIN_SIZE 32 |
55 | |
56 | /* Definitions for the core NCR5380 driver. */ |
57 | |
58 | #define NCR5380_implementation_fields /* none */ |
59 | |
60 | static u8 (*atari_scsi_reg_read)(unsigned int); |
61 | static void (*atari_scsi_reg_write)(unsigned int, u8); |
62 | |
63 | #define NCR5380_read(reg) atari_scsi_reg_read(reg) |
64 | #define NCR5380_write(reg, value) atari_scsi_reg_write(reg, value) |
65 | |
66 | #define NCR5380_queue_command atari_scsi_queue_command |
67 | #define NCR5380_abort atari_scsi_abort |
68 | #define NCR5380_info atari_scsi_info |
69 | |
70 | #define NCR5380_dma_xfer_len atari_scsi_dma_xfer_len |
71 | #define NCR5380_dma_recv_setup atari_scsi_dma_recv_setup |
72 | #define NCR5380_dma_send_setup atari_scsi_dma_send_setup |
73 | #define NCR5380_dma_residual atari_scsi_dma_residual |
74 | |
75 | #define NCR5380_acquire_dma_irq(instance) falcon_get_lock(instance) |
76 | #define NCR5380_release_dma_irq(instance) falcon_release_lock() |
77 | |
78 | #include "NCR5380.h" |
79 | |
80 | |
81 | #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI) |
82 | |
83 | #define SCSI_DMA_WRITE_P(elt,val) \ |
84 | do { \ |
85 | unsigned long v = val; \ |
86 | tt_scsi_dma.elt##_lo = v & 0xff; \ |
87 | v >>= 8; \ |
88 | tt_scsi_dma.elt##_lmd = v & 0xff; \ |
89 | v >>= 8; \ |
90 | tt_scsi_dma.elt##_hmd = v & 0xff; \ |
91 | v >>= 8; \ |
92 | tt_scsi_dma.elt##_hi = v & 0xff; \ |
93 | } while(0) |
94 | |
95 | #define SCSI_DMA_READ_P(elt) \ |
96 | (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \ |
97 | (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \ |
98 | (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \ |
99 | (unsigned long)tt_scsi_dma.elt##_lo) |
100 | |
101 | |
102 | static inline void SCSI_DMA_SETADR(unsigned long adr) |
103 | { |
104 | st_dma.dma_lo = (unsigned char)adr; |
105 | MFPDELAY(); |
106 | adr >>= 8; |
107 | st_dma.dma_md = (unsigned char)adr; |
108 | MFPDELAY(); |
109 | adr >>= 8; |
110 | st_dma.dma_hi = (unsigned char)adr; |
111 | MFPDELAY(); |
112 | } |
113 | |
114 | static inline unsigned long SCSI_DMA_GETADR(void) |
115 | { |
116 | unsigned long adr; |
117 | adr = st_dma.dma_lo; |
118 | MFPDELAY(); |
119 | adr |= (st_dma.dma_md & 0xff) << 8; |
120 | MFPDELAY(); |
121 | adr |= (st_dma.dma_hi & 0xff) << 16; |
122 | MFPDELAY(); |
123 | return adr; |
124 | } |
125 | |
126 | static void atari_scsi_fetch_restbytes(void); |
127 | |
128 | static unsigned long atari_dma_residual, atari_dma_startaddr; |
129 | static short atari_dma_active; |
130 | /* pointer to the dribble buffer */ |
131 | static char *atari_dma_buffer; |
132 | /* precalculated physical address of the dribble buffer */ |
133 | static unsigned long atari_dma_phys_buffer; |
134 | /* != 0 tells the Falcon int handler to copy data from the dribble buffer */ |
135 | static char *atari_dma_orig_addr; |
136 | /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use |
137 | * scatter-gather anyway, so most transfers are 1024 byte only. In the rare |
138 | * cases where requests to physical contiguous buffers have been merged, this |
139 | * request is <= 4k (one page). So I don't think we have to split transfers |
140 | * just due to this buffer size... |
141 | */ |
142 | #define STRAM_BUFFER_SIZE (4096) |
143 | /* mask for address bits that can't be used with the ST-DMA */ |
144 | static unsigned long atari_dma_stram_mask; |
145 | #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0) |
146 | |
147 | static int setup_can_queue = -1; |
148 | module_param(setup_can_queue, int, 0); |
149 | static int setup_cmd_per_lun = -1; |
150 | module_param(setup_cmd_per_lun, int, 0); |
151 | static int setup_sg_tablesize = -1; |
152 | module_param(setup_sg_tablesize, int, 0); |
153 | static int setup_hostid = -1; |
154 | module_param(setup_hostid, int, 0); |
155 | static int setup_toshiba_delay = -1; |
156 | module_param(setup_toshiba_delay, int, 0); |
157 | |
158 | |
159 | static int scsi_dma_is_ignored_buserr(unsigned char dma_stat) |
160 | { |
161 | int i; |
162 | unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr; |
163 | |
164 | if (dma_stat & 0x01) { |
165 | |
166 | /* A bus error happens when DMA-ing from the last page of a |
167 | * physical memory chunk (DMA prefetch!), but that doesn't hurt. |
168 | * Check for this case: |
169 | */ |
170 | |
171 | for (i = 0; i < m68k_num_memory; ++i) { |
172 | end_addr = m68k_memory[i].addr + m68k_memory[i].size; |
173 | if (end_addr <= addr && addr <= end_addr + 4) |
174 | return 1; |
175 | } |
176 | } |
177 | return 0; |
178 | } |
179 | |
180 | |
181 | static irqreturn_t scsi_tt_intr(int irq, void *dev) |
182 | { |
183 | struct Scsi_Host *instance = dev; |
184 | struct NCR5380_hostdata *hostdata = shost_priv(shost: instance); |
185 | int dma_stat; |
186 | |
187 | dma_stat = tt_scsi_dma.dma_ctrl; |
188 | |
189 | dsprintk(NDEBUG_INTR, instance, "NCR5380 interrupt, DMA status = %02x\n" , |
190 | dma_stat & 0xff); |
191 | |
192 | /* Look if it was the DMA that has interrupted: First possibility |
193 | * is that a bus error occurred... |
194 | */ |
195 | if (dma_stat & 0x80) { |
196 | if (!scsi_dma_is_ignored_buserr(dma_stat)) { |
197 | printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n" , |
198 | SCSI_DMA_READ_P(dma_addr)); |
199 | printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!" ); |
200 | } |
201 | } |
202 | |
203 | /* If the DMA is active but not finished, we have the case |
204 | * that some other 5380 interrupt occurred within the DMA transfer. |
205 | * This means we have residual bytes, if the desired end address |
206 | * is not yet reached. Maybe we have to fetch some bytes from the |
207 | * rest data register, too. The residual must be calculated from |
208 | * the address pointer, not the counter register, because only the |
209 | * addr reg counts bytes not yet written and pending in the rest |
210 | * data reg! |
211 | */ |
212 | if ((dma_stat & 0x02) && !(dma_stat & 0x40)) { |
213 | atari_dma_residual = hostdata->dma_len - |
214 | (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr); |
215 | |
216 | dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n" , |
217 | atari_dma_residual); |
218 | |
219 | if ((signed int)atari_dma_residual < 0) |
220 | atari_dma_residual = 0; |
221 | if ((dma_stat & 1) == 0) { |
222 | /* |
223 | * After read operations, we maybe have to |
224 | * transport some rest bytes |
225 | */ |
226 | atari_scsi_fetch_restbytes(); |
227 | } else { |
228 | /* |
229 | * There seems to be a nasty bug in some SCSI-DMA/NCR |
230 | * combinations: If a target disconnects while a write |
231 | * operation is going on, the address register of the |
232 | * DMA may be a few bytes farer than it actually read. |
233 | * This is probably due to DMA prefetching and a delay |
234 | * between DMA and NCR. Experiments showed that the |
235 | * dma_addr is 9 bytes to high, but this could vary. |
236 | * The problem is, that the residual is thus calculated |
237 | * wrong and the next transfer will start behind where |
238 | * it should. So we round up the residual to the next |
239 | * multiple of a sector size, if it isn't already a |
240 | * multiple and the originally expected transfer size |
241 | * was. The latter condition is there to ensure that |
242 | * the correction is taken only for "real" data |
243 | * transfers and not for, e.g., the parameters of some |
244 | * other command. These shouldn't disconnect anyway. |
245 | */ |
246 | if (atari_dma_residual & 0x1ff) { |
247 | dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, " |
248 | "difference %ld bytes\n" , |
249 | 512 - (atari_dma_residual & 0x1ff)); |
250 | atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff; |
251 | } |
252 | } |
253 | tt_scsi_dma.dma_ctrl = 0; |
254 | } |
255 | |
256 | /* If the DMA is finished, fetch the rest bytes and turn it off */ |
257 | if (dma_stat & 0x40) { |
258 | atari_dma_residual = 0; |
259 | if ((dma_stat & 1) == 0) |
260 | atari_scsi_fetch_restbytes(); |
261 | tt_scsi_dma.dma_ctrl = 0; |
262 | } |
263 | |
264 | NCR5380_intr(irq, dev_id: dev); |
265 | |
266 | return IRQ_HANDLED; |
267 | } |
268 | |
269 | |
270 | static irqreturn_t scsi_falcon_intr(int irq, void *dev) |
271 | { |
272 | struct Scsi_Host *instance = dev; |
273 | struct NCR5380_hostdata *hostdata = shost_priv(shost: instance); |
274 | int dma_stat; |
275 | |
276 | /* Turn off DMA and select sector counter register before |
277 | * accessing the status register (Atari recommendation!) |
278 | */ |
279 | st_dma.dma_mode_status = 0x90; |
280 | dma_stat = st_dma.dma_mode_status; |
281 | |
282 | /* Bit 0 indicates some error in the DMA process... don't know |
283 | * what happened exactly (no further docu). |
284 | */ |
285 | if (!(dma_stat & 0x01)) { |
286 | /* DMA error */ |
287 | printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n" , SCSI_DMA_GETADR()); |
288 | } |
289 | |
290 | /* If the DMA was active, but now bit 1 is not clear, it is some |
291 | * other 5380 interrupt that finishes the DMA transfer. We have to |
292 | * calculate the number of residual bytes and give a warning if |
293 | * bytes are stuck in the ST-DMA fifo (there's no way to reach them!) |
294 | */ |
295 | if (atari_dma_active && (dma_stat & 0x02)) { |
296 | unsigned long transferred; |
297 | |
298 | transferred = SCSI_DMA_GETADR() - atari_dma_startaddr; |
299 | /* The ST-DMA address is incremented in 2-byte steps, but the |
300 | * data are written only in 16-byte chunks. If the number of |
301 | * transferred bytes is not divisible by 16, the remainder is |
302 | * lost somewhere in outer space. |
303 | */ |
304 | if (transferred & 15) |
305 | printk(KERN_ERR "SCSI DMA error: %ld bytes lost in " |
306 | "ST-DMA fifo\n" , transferred & 15); |
307 | |
308 | atari_dma_residual = hostdata->dma_len - transferred; |
309 | dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n" , |
310 | atari_dma_residual); |
311 | } else |
312 | atari_dma_residual = 0; |
313 | atari_dma_active = 0; |
314 | |
315 | if (atari_dma_orig_addr) { |
316 | /* If the dribble buffer was used on a read operation, copy the DMA-ed |
317 | * data to the original destination address. |
318 | */ |
319 | memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr), |
320 | hostdata->dma_len - atari_dma_residual); |
321 | atari_dma_orig_addr = NULL; |
322 | } |
323 | |
324 | NCR5380_intr(irq, dev_id: dev); |
325 | |
326 | return IRQ_HANDLED; |
327 | } |
328 | |
329 | |
330 | static void atari_scsi_fetch_restbytes(void) |
331 | { |
332 | int nr; |
333 | char *src, *dst; |
334 | unsigned long phys_dst; |
335 | |
336 | /* fetch rest bytes in the DMA register */ |
337 | phys_dst = SCSI_DMA_READ_P(dma_addr); |
338 | nr = phys_dst & 3; |
339 | if (nr) { |
340 | /* there are 'nr' bytes left for the last long address |
341 | before the DMA pointer */ |
342 | phys_dst ^= nr; |
343 | dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx" , |
344 | nr, phys_dst); |
345 | /* The content of the DMA pointer is a physical address! */ |
346 | dst = phys_to_virt(address: phys_dst); |
347 | dprintk(NDEBUG_DMA, " = virt addr %p\n" , dst); |
348 | for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr) |
349 | *dst++ = *src++; |
350 | } |
351 | } |
352 | |
353 | |
354 | /* This function releases the lock on the DMA chip if there is no |
355 | * connected command and the disconnected queue is empty. |
356 | */ |
357 | |
358 | static void falcon_release_lock(void) |
359 | { |
360 | if (IS_A_TT()) |
361 | return; |
362 | |
363 | if (stdma_is_locked_by(scsi_falcon_intr)) |
364 | stdma_release(); |
365 | } |
366 | |
367 | /* This function manages the locking of the ST-DMA. |
368 | * If the DMA isn't locked already for SCSI, it tries to lock it by |
369 | * calling stdma_lock(). But if the DMA is locked by the SCSI code and |
370 | * there are other drivers waiting for the chip, we do not issue the |
371 | * command immediately but tell the SCSI mid-layer to defer. |
372 | */ |
373 | |
374 | static int falcon_get_lock(struct Scsi_Host *instance) |
375 | { |
376 | if (IS_A_TT()) |
377 | return 1; |
378 | |
379 | if (stdma_is_locked_by(scsi_falcon_intr)) |
380 | return 1; |
381 | |
382 | /* stdma_lock() may sleep which means it can't be used here */ |
383 | return stdma_try_lock(scsi_falcon_intr, instance); |
384 | } |
385 | |
386 | #ifndef MODULE |
387 | static int __init atari_scsi_setup(char *str) |
388 | { |
389 | /* Format of atascsi parameter is: |
390 | * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> |
391 | * Defaults depend on TT or Falcon, determined at run time. |
392 | * Negative values mean don't change. |
393 | */ |
394 | int ints[8]; |
395 | |
396 | get_options(str, ARRAY_SIZE(ints), ints); |
397 | |
398 | if (ints[0] < 1) { |
399 | printk("atari_scsi_setup: no arguments!\n" ); |
400 | return 0; |
401 | } |
402 | if (ints[0] >= 1) |
403 | setup_can_queue = ints[1]; |
404 | if (ints[0] >= 2) |
405 | setup_cmd_per_lun = ints[2]; |
406 | if (ints[0] >= 3) |
407 | setup_sg_tablesize = ints[3]; |
408 | if (ints[0] >= 4) |
409 | setup_hostid = ints[4]; |
410 | /* ints[5] (use_tagged_queuing) is ignored */ |
411 | /* ints[6] (use_pdma) is ignored */ |
412 | if (ints[0] >= 7) |
413 | setup_toshiba_delay = ints[7]; |
414 | |
415 | return 1; |
416 | } |
417 | |
418 | __setup("atascsi=" , atari_scsi_setup); |
419 | #endif /* !MODULE */ |
420 | |
421 | static unsigned long atari_scsi_dma_setup(struct NCR5380_hostdata *hostdata, |
422 | void *data, unsigned long count, |
423 | int dir) |
424 | { |
425 | unsigned long addr = virt_to_phys(address: data); |
426 | |
427 | dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, dir = %d\n" , |
428 | hostdata->host->host_no, data, addr, count, dir); |
429 | |
430 | if (!IS_A_TT() && !STRAM_ADDR(addr)) { |
431 | /* If we have a non-DMAable address on a Falcon, use the dribble |
432 | * buffer; 'orig_addr' != 0 in the read case tells the interrupt |
433 | * handler to copy data from the dribble buffer to the originally |
434 | * wanted address. |
435 | */ |
436 | if (dir) |
437 | memcpy(atari_dma_buffer, data, count); |
438 | else |
439 | atari_dma_orig_addr = data; |
440 | addr = atari_dma_phys_buffer; |
441 | } |
442 | |
443 | atari_dma_startaddr = addr; /* Needed for calculating residual later. */ |
444 | |
445 | /* Cache cleanup stuff: On writes, push any dirty cache out before sending |
446 | * it to the peripheral. (Must be done before DMA setup, since at least |
447 | * the ST-DMA begins to fill internal buffers right after setup. For |
448 | * reads, invalidate any cache, may be altered after DMA without CPU |
449 | * knowledge. |
450 | * |
451 | * ++roman: For the Medusa, there's no need at all for that cache stuff, |
452 | * because the hardware does bus snooping (fine!). |
453 | */ |
454 | dma_cache_maintenance(addr, count, dir); |
455 | |
456 | if (IS_A_TT()) { |
457 | tt_scsi_dma.dma_ctrl = dir; |
458 | SCSI_DMA_WRITE_P(dma_addr, addr); |
459 | SCSI_DMA_WRITE_P(dma_cnt, count); |
460 | tt_scsi_dma.dma_ctrl = dir | 2; |
461 | } else { /* ! IS_A_TT */ |
462 | |
463 | /* set address */ |
464 | SCSI_DMA_SETADR(adr: addr); |
465 | |
466 | /* toggle direction bit to clear FIFO and set DMA direction */ |
467 | dir <<= 8; |
468 | st_dma.dma_mode_status = 0x90 | dir; |
469 | st_dma.dma_mode_status = 0x90 | (dir ^ 0x100); |
470 | st_dma.dma_mode_status = 0x90 | dir; |
471 | udelay(40); |
472 | /* On writes, round up the transfer length to the next multiple of 512 |
473 | * (see also comment at atari_dma_xfer_len()). */ |
474 | st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9; |
475 | udelay(40); |
476 | st_dma.dma_mode_status = 0x10 | dir; |
477 | udelay(40); |
478 | /* need not restore value of dir, only boolean value is tested */ |
479 | atari_dma_active = 1; |
480 | } |
481 | |
482 | return count; |
483 | } |
484 | |
485 | static inline int atari_scsi_dma_recv_setup(struct NCR5380_hostdata *hostdata, |
486 | unsigned char *data, int count) |
487 | { |
488 | return atari_scsi_dma_setup(hostdata, data, count, dir: 0); |
489 | } |
490 | |
491 | static inline int atari_scsi_dma_send_setup(struct NCR5380_hostdata *hostdata, |
492 | unsigned char *data, int count) |
493 | { |
494 | return atari_scsi_dma_setup(hostdata, data, count, dir: 1); |
495 | } |
496 | |
497 | static int atari_scsi_dma_residual(struct NCR5380_hostdata *hostdata) |
498 | { |
499 | return atari_dma_residual; |
500 | } |
501 | |
502 | |
503 | #define CMD_SURELY_BLOCK_MODE 0 |
504 | #define CMD_SURELY_BYTE_MODE 1 |
505 | #define CMD_MODE_UNKNOWN 2 |
506 | |
507 | static int falcon_classify_cmd(struct scsi_cmnd *cmd) |
508 | { |
509 | unsigned char opcode = cmd->cmnd[0]; |
510 | |
511 | if (opcode == READ_DEFECT_DATA || opcode == READ_LONG || |
512 | opcode == READ_BUFFER) |
513 | return CMD_SURELY_BYTE_MODE; |
514 | else if (opcode == READ_6 || opcode == READ_10 || |
515 | opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE || |
516 | opcode == RECOVER_BUFFERED_DATA) { |
517 | /* In case of a sequential-access target (tape), special care is |
518 | * needed here: The transfer is block-mode only if the 'fixed' bit is |
519 | * set! */ |
520 | if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1)) |
521 | return CMD_SURELY_BYTE_MODE; |
522 | else |
523 | return CMD_SURELY_BLOCK_MODE; |
524 | } else |
525 | return CMD_MODE_UNKNOWN; |
526 | } |
527 | |
528 | |
529 | /* This function calculates the number of bytes that can be transferred via |
530 | * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the |
531 | * ST-DMA chip. There are only multiples of 512 bytes possible and max. |
532 | * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not |
533 | * possible on the Falcon, since that would require to program the DMA for |
534 | * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have |
535 | * the overrun problem, so this question is academic :-) |
536 | */ |
537 | |
538 | static int atari_scsi_dma_xfer_len(struct NCR5380_hostdata *hostdata, |
539 | struct scsi_cmnd *cmd) |
540 | { |
541 | int wanted_len = NCR5380_to_ncmd(cmd)->this_residual; |
542 | int possible_len, limit; |
543 | |
544 | if (wanted_len < DMA_MIN_SIZE) |
545 | return 0; |
546 | |
547 | if (IS_A_TT()) |
548 | /* TT SCSI DMA can transfer arbitrary #bytes */ |
549 | return wanted_len; |
550 | |
551 | /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max. |
552 | * 255*512 bytes, but this should be enough) |
553 | * |
554 | * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands |
555 | * that return a number of bytes which cannot be known beforehand. In this |
556 | * case, the given transfer length is an "allocation length". Now it |
557 | * can happen that this allocation length is a multiple of 512 bytes and |
558 | * the DMA is used. But if not n*512 bytes really arrive, some input data |
559 | * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish |
560 | * between commands that do block transfers and those that do byte |
561 | * transfers. But this isn't easy... there are lots of vendor specific |
562 | * commands, and the user can issue any command via the |
563 | * SCSI_IOCTL_SEND_COMMAND. |
564 | * |
565 | * The solution: We classify SCSI commands in 1) surely block-mode cmd.s, |
566 | * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1) |
567 | * and 3), the thing to do is obvious: allow any number of blocks via DMA |
568 | * or none. In case 2), we apply some heuristic: Byte mode is assumed if |
569 | * the transfer (allocation) length is < 1024, hoping that no cmd. not |
570 | * explicitly known as byte mode have such big allocation lengths... |
571 | * BTW, all the discussion above applies only to reads. DMA writes are |
572 | * unproblematic anyways, since the targets aborts the transfer after |
573 | * receiving a sufficient number of bytes. |
574 | * |
575 | * Another point: If the transfer is from/to an non-ST-RAM address, we |
576 | * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes. |
577 | */ |
578 | |
579 | if (cmd->sc_data_direction == DMA_TO_DEVICE) { |
580 | /* Write operation can always use the DMA, but the transfer size must |
581 | * be rounded up to the next multiple of 512 (atari_dma_setup() does |
582 | * this). |
583 | */ |
584 | possible_len = wanted_len; |
585 | } else { |
586 | /* Read operations: if the wanted transfer length is not a multiple of |
587 | * 512, we cannot use DMA, since the ST-DMA cannot split transfers |
588 | * (no interrupt on DMA finished!) |
589 | */ |
590 | if (wanted_len & 0x1ff) |
591 | possible_len = 0; |
592 | else { |
593 | /* Now classify the command (see above) and decide whether it is |
594 | * allowed to do DMA at all */ |
595 | switch (falcon_classify_cmd(cmd)) { |
596 | case CMD_SURELY_BLOCK_MODE: |
597 | possible_len = wanted_len; |
598 | break; |
599 | case CMD_SURELY_BYTE_MODE: |
600 | possible_len = 0; /* DMA prohibited */ |
601 | break; |
602 | case CMD_MODE_UNKNOWN: |
603 | default: |
604 | /* For unknown commands assume block transfers if the transfer |
605 | * size/allocation length is >= 1024 */ |
606 | possible_len = (wanted_len < 1024) ? 0 : wanted_len; |
607 | break; |
608 | } |
609 | } |
610 | } |
611 | |
612 | /* Last step: apply the hard limit on DMA transfers */ |
613 | limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(NCR5380_to_ncmd(cmd)->ptr))) ? |
614 | STRAM_BUFFER_SIZE : 255*512; |
615 | if (possible_len > limit) |
616 | possible_len = limit; |
617 | |
618 | if (possible_len != wanted_len) |
619 | dprintk(NDEBUG_DMA, "DMA transfer now %d bytes instead of %d\n" , |
620 | possible_len, wanted_len); |
621 | |
622 | return possible_len; |
623 | } |
624 | |
625 | |
626 | /* NCR5380 register access functions |
627 | * |
628 | * There are separate functions for TT and Falcon, because the access |
629 | * methods are quite different. The calling macros NCR5380_read and |
630 | * NCR5380_write call these functions via function pointers. |
631 | */ |
632 | |
633 | static u8 atari_scsi_tt_reg_read(unsigned int reg) |
634 | { |
635 | return tt_scsi_regp[reg * 2]; |
636 | } |
637 | |
638 | static void atari_scsi_tt_reg_write(unsigned int reg, u8 value) |
639 | { |
640 | tt_scsi_regp[reg * 2] = value; |
641 | } |
642 | |
643 | static u8 atari_scsi_falcon_reg_read(unsigned int reg) |
644 | { |
645 | unsigned long flags; |
646 | u8 result; |
647 | |
648 | reg += 0x88; |
649 | local_irq_save(flags); |
650 | dma_wd.dma_mode_status = (u_short)reg; |
651 | result = (u8)dma_wd.fdc_acces_seccount; |
652 | local_irq_restore(flags); |
653 | return result; |
654 | } |
655 | |
656 | static void atari_scsi_falcon_reg_write(unsigned int reg, u8 value) |
657 | { |
658 | unsigned long flags; |
659 | |
660 | reg += 0x88; |
661 | local_irq_save(flags); |
662 | dma_wd.dma_mode_status = (u_short)reg; |
663 | dma_wd.fdc_acces_seccount = (u_short)value; |
664 | local_irq_restore(flags); |
665 | } |
666 | |
667 | |
668 | #include "NCR5380.c" |
669 | |
670 | static int atari_scsi_host_reset(struct scsi_cmnd *cmd) |
671 | { |
672 | int rv; |
673 | unsigned long flags; |
674 | |
675 | local_irq_save(flags); |
676 | |
677 | /* Abort a maybe active DMA transfer */ |
678 | if (IS_A_TT()) { |
679 | tt_scsi_dma.dma_ctrl = 0; |
680 | } else { |
681 | if (stdma_is_locked_by(scsi_falcon_intr)) |
682 | st_dma.dma_mode_status = 0x90; |
683 | atari_dma_active = 0; |
684 | atari_dma_orig_addr = NULL; |
685 | } |
686 | |
687 | rv = NCR5380_host_reset(cmd); |
688 | |
689 | /* The 5380 raises its IRQ line while _RST is active but the ST DMA |
690 | * "lock" has been released so this interrupt may end up handled by |
691 | * floppy or IDE driver (if one of them holds the lock). The NCR5380 |
692 | * interrupt flag has been cleared already. |
693 | */ |
694 | |
695 | local_irq_restore(flags); |
696 | |
697 | return rv; |
698 | } |
699 | |
700 | #define DRV_MODULE_NAME "atari_scsi" |
701 | #define PFX DRV_MODULE_NAME ": " |
702 | |
703 | static struct scsi_host_template atari_scsi_template = { |
704 | .module = THIS_MODULE, |
705 | .proc_name = DRV_MODULE_NAME, |
706 | .name = "Atari native SCSI" , |
707 | .info = atari_scsi_info, |
708 | .queuecommand = atari_scsi_queue_command, |
709 | .eh_abort_handler = atari_scsi_abort, |
710 | .eh_host_reset_handler = atari_scsi_host_reset, |
711 | .this_id = 7, |
712 | .cmd_per_lun = 2, |
713 | .dma_boundary = PAGE_SIZE - 1, |
714 | .cmd_size = sizeof(struct NCR5380_cmd), |
715 | }; |
716 | |
717 | static int __init atari_scsi_probe(struct platform_device *pdev) |
718 | { |
719 | struct Scsi_Host *instance; |
720 | int error; |
721 | struct resource *irq; |
722 | int host_flags = 0; |
723 | |
724 | irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); |
725 | if (!irq) |
726 | return -ENODEV; |
727 | |
728 | if (ATARIHW_PRESENT(TT_SCSI)) { |
729 | atari_scsi_reg_read = atari_scsi_tt_reg_read; |
730 | atari_scsi_reg_write = atari_scsi_tt_reg_write; |
731 | } else { |
732 | atari_scsi_reg_read = atari_scsi_falcon_reg_read; |
733 | atari_scsi_reg_write = atari_scsi_falcon_reg_write; |
734 | } |
735 | |
736 | if (ATARIHW_PRESENT(TT_SCSI)) { |
737 | atari_scsi_template.can_queue = 16; |
738 | atari_scsi_template.sg_tablesize = SG_ALL; |
739 | } else { |
740 | atari_scsi_template.can_queue = 1; |
741 | atari_scsi_template.sg_tablesize = 1; |
742 | } |
743 | |
744 | if (setup_can_queue > 0) |
745 | atari_scsi_template.can_queue = setup_can_queue; |
746 | |
747 | if (setup_cmd_per_lun > 0) |
748 | atari_scsi_template.cmd_per_lun = setup_cmd_per_lun; |
749 | |
750 | /* Don't increase sg_tablesize on Falcon! */ |
751 | if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize > 0) |
752 | atari_scsi_template.sg_tablesize = setup_sg_tablesize; |
753 | |
754 | if (setup_hostid >= 0) { |
755 | atari_scsi_template.this_id = setup_hostid & 7; |
756 | } else if (IS_REACHABLE(CONFIG_NVRAM)) { |
757 | /* Test if a host id is set in the NVRam */ |
758 | if (ATARIHW_PRESENT(TT_CLK)) { |
759 | unsigned char b; |
760 | loff_t offset = 16; |
761 | ssize_t count = nvram_read(buf: &b, count: 1, ppos: &offset); |
762 | |
763 | /* Arbitration enabled? (for TOS) |
764 | * If yes, use configured host ID |
765 | */ |
766 | if ((count == 1) && (b & 0x80)) |
767 | atari_scsi_template.this_id = b & 7; |
768 | } |
769 | } |
770 | |
771 | /* If running on a Falcon and if there's TT-Ram (i.e., more than one |
772 | * memory block, since there's always ST-Ram in a Falcon), then |
773 | * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers |
774 | * from/to alternative Ram. |
775 | */ |
776 | if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) && |
777 | m68k_realnum_memory > 1) { |
778 | atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI" ); |
779 | if (!atari_dma_buffer) { |
780 | pr_err(PFX "can't allocate ST-RAM double buffer\n" ); |
781 | return -ENOMEM; |
782 | } |
783 | atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer); |
784 | atari_dma_orig_addr = NULL; |
785 | } |
786 | |
787 | instance = scsi_host_alloc(&atari_scsi_template, |
788 | sizeof(struct NCR5380_hostdata)); |
789 | if (!instance) { |
790 | error = -ENOMEM; |
791 | goto fail_alloc; |
792 | } |
793 | |
794 | instance->irq = irq->start; |
795 | |
796 | host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP; |
797 | host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0; |
798 | |
799 | error = NCR5380_init(instance, flags: host_flags); |
800 | if (error) |
801 | goto fail_init; |
802 | |
803 | if (IS_A_TT()) { |
804 | error = request_irq(irq: instance->irq, handler: scsi_tt_intr, flags: 0, |
805 | name: "NCR5380" , dev: instance); |
806 | if (error) { |
807 | pr_err(PFX "request irq %d failed, aborting\n" , |
808 | instance->irq); |
809 | goto fail_irq; |
810 | } |
811 | tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */ |
812 | |
813 | tt_scsi_dma.dma_ctrl = 0; |
814 | atari_dma_residual = 0; |
815 | |
816 | /* While the read overruns (described by Drew Eckhardt in |
817 | * NCR5380.c) never happened on TTs, they do in fact on the |
818 | * Medusa (This was the cause why SCSI didn't work right for |
819 | * so long there.) Since handling the overruns slows down |
820 | * a bit, I turned the #ifdef's into a runtime condition. |
821 | * |
822 | * In principle it should be sufficient to do max. 1 byte with |
823 | * PIO, but there is another problem on the Medusa with the DMA |
824 | * rest data register. So read_overruns is currently set |
825 | * to 4 to avoid having transfers that aren't a multiple of 4. |
826 | * If the rest data bug is fixed, this can be lowered to 1. |
827 | */ |
828 | if (MACH_IS_MEDUSA) { |
829 | struct NCR5380_hostdata *hostdata = |
830 | shost_priv(shost: instance); |
831 | |
832 | hostdata->read_overruns = 4; |
833 | } |
834 | } else { |
835 | /* Nothing to do for the interrupt: the ST-DMA is initialized |
836 | * already. |
837 | */ |
838 | atari_dma_residual = 0; |
839 | atari_dma_active = 0; |
840 | atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 |
841 | : 0xff000000); |
842 | } |
843 | |
844 | NCR5380_maybe_reset_bus(instance); |
845 | |
846 | error = scsi_add_host(host: instance, NULL); |
847 | if (error) |
848 | goto fail_host; |
849 | |
850 | platform_set_drvdata(pdev, data: instance); |
851 | |
852 | scsi_scan_host(instance); |
853 | return 0; |
854 | |
855 | fail_host: |
856 | if (IS_A_TT()) |
857 | free_irq(instance->irq, instance); |
858 | fail_irq: |
859 | NCR5380_exit(instance); |
860 | fail_init: |
861 | scsi_host_put(t: instance); |
862 | fail_alloc: |
863 | if (atari_dma_buffer) |
864 | atari_stram_free(atari_dma_buffer); |
865 | return error; |
866 | } |
867 | |
868 | static void __exit atari_scsi_remove(struct platform_device *pdev) |
869 | { |
870 | struct Scsi_Host *instance = platform_get_drvdata(pdev); |
871 | |
872 | scsi_remove_host(instance); |
873 | if (IS_A_TT()) |
874 | free_irq(instance->irq, instance); |
875 | NCR5380_exit(instance); |
876 | scsi_host_put(t: instance); |
877 | if (atari_dma_buffer) |
878 | atari_stram_free(atari_dma_buffer); |
879 | } |
880 | |
881 | static struct platform_driver atari_scsi_driver = { |
882 | .remove_new = __exit_p(atari_scsi_remove), |
883 | .driver = { |
884 | .name = DRV_MODULE_NAME, |
885 | }, |
886 | }; |
887 | |
888 | module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe); |
889 | |
890 | MODULE_ALIAS("platform:" DRV_MODULE_NAME); |
891 | MODULE_LICENSE("GPL" ); |
892 | |