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1da177e4 LT |
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 | ||
1da177e4 LT |
68 | #include <linux/module.h> |
69 | ||
70 | #define NDEBUG (0) | |
71 | ||
72 | #define NDEBUG_ABORT 0x800000 | |
73 | #define NDEBUG_TAGS 0x1000000 | |
74 | #define NDEBUG_MERGING 0x2000000 | |
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/sched.h> | |
90 | #include <linux/interrupt.h> | |
91 | #include <linux/init.h> | |
92 | #include <linux/nvram.h> | |
93 | #include <linux/bitops.h> | |
94 | ||
95 | #include <asm/setup.h> | |
96 | #include <asm/atarihw.h> | |
97 | #include <asm/atariints.h> | |
98 | #include <asm/page.h> | |
99 | #include <asm/pgtable.h> | |
100 | #include <asm/irq.h> | |
101 | #include <asm/traps.h> | |
102 | ||
103 | #include "scsi.h" | |
104 | #include <scsi/scsi_host.h> | |
105 | #include "atari_scsi.h" | |
106 | #include "NCR5380.h" | |
107 | #include <asm/atari_stdma.h> | |
108 | #include <asm/atari_stram.h> | |
109 | #include <asm/io.h> | |
110 | ||
111 | #include <linux/stat.h> | |
112 | ||
113 | #define IS_A_TT() ATARIHW_PRESENT(TT_SCSI) | |
114 | ||
115 | #define SCSI_DMA_WRITE_P(elt,val) \ | |
116 | do { \ | |
117 | unsigned long v = val; \ | |
118 | tt_scsi_dma.elt##_lo = v & 0xff; \ | |
119 | v >>= 8; \ | |
120 | tt_scsi_dma.elt##_lmd = v & 0xff; \ | |
121 | v >>= 8; \ | |
122 | tt_scsi_dma.elt##_hmd = v & 0xff; \ | |
123 | v >>= 8; \ | |
124 | tt_scsi_dma.elt##_hi = v & 0xff; \ | |
125 | } while(0) | |
126 | ||
127 | #define SCSI_DMA_READ_P(elt) \ | |
128 | (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) | \ | |
129 | (unsigned long)tt_scsi_dma.elt##_hmd) << 8) | \ | |
130 | (unsigned long)tt_scsi_dma.elt##_lmd) << 8) | \ | |
131 | (unsigned long)tt_scsi_dma.elt##_lo) | |
132 | ||
133 | ||
134 | static inline void SCSI_DMA_SETADR(unsigned long adr) | |
135 | { | |
136 | st_dma.dma_lo = (unsigned char)adr; | |
137 | MFPDELAY(); | |
138 | adr >>= 8; | |
139 | st_dma.dma_md = (unsigned char)adr; | |
140 | MFPDELAY(); | |
141 | adr >>= 8; | |
142 | st_dma.dma_hi = (unsigned char)adr; | |
143 | MFPDELAY(); | |
144 | } | |
145 | ||
146 | static inline unsigned long SCSI_DMA_GETADR(void) | |
147 | { | |
148 | unsigned long adr; | |
149 | adr = st_dma.dma_lo; | |
150 | MFPDELAY(); | |
151 | adr |= (st_dma.dma_md & 0xff) << 8; | |
152 | MFPDELAY(); | |
153 | adr |= (st_dma.dma_hi & 0xff) << 16; | |
154 | MFPDELAY(); | |
155 | return adr; | |
156 | } | |
157 | ||
158 | static inline void ENABLE_IRQ(void) | |
159 | { | |
160 | if (IS_A_TT()) | |
161 | atari_enable_irq(IRQ_TT_MFP_SCSI); | |
162 | else | |
163 | atari_enable_irq(IRQ_MFP_FSCSI); | |
164 | } | |
165 | ||
166 | static inline void DISABLE_IRQ(void) | |
167 | { | |
168 | if (IS_A_TT()) | |
169 | atari_disable_irq(IRQ_TT_MFP_SCSI); | |
170 | else | |
171 | atari_disable_irq(IRQ_MFP_FSCSI); | |
172 | } | |
173 | ||
174 | ||
175 | #define HOSTDATA_DMALEN (((struct NCR5380_hostdata *) \ | |
176 | (atari_scsi_host->hostdata))->dma_len) | |
177 | ||
178 | /* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms, | |
179 | * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more | |
180 | * need ten times the standard value... */ | |
181 | #ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY | |
182 | #define AFTER_RESET_DELAY (HZ/2) | |
183 | #else | |
184 | #define AFTER_RESET_DELAY (5*HZ/2) | |
185 | #endif | |
186 | ||
187 | /***************************** Prototypes *****************************/ | |
188 | ||
189 | #ifdef REAL_DMA | |
190 | static int scsi_dma_is_ignored_buserr( unsigned char dma_stat ); | |
191 | static void atari_scsi_fetch_restbytes( void ); | |
192 | static long atari_scsi_dma_residual( struct Scsi_Host *instance ); | |
193 | static int falcon_classify_cmd( Scsi_Cmnd *cmd ); | |
194 | static unsigned long atari_dma_xfer_len( unsigned long wanted_len, | |
195 | Scsi_Cmnd *cmd, int write_flag ); | |
196 | #endif | |
7d12e780 DH |
197 | static irqreturn_t scsi_tt_intr( int irq, void *dummy); |
198 | static irqreturn_t scsi_falcon_intr( int irq, void *dummy); | |
1da177e4 LT |
199 | static void falcon_release_lock_if_possible( struct NCR5380_hostdata * |
200 | hostdata ); | |
201 | static void falcon_get_lock( void ); | |
202 | #ifdef CONFIG_ATARI_SCSI_RESET_BOOT | |
203 | static void atari_scsi_reset_boot( void ); | |
204 | #endif | |
205 | static unsigned char atari_scsi_tt_reg_read( unsigned char reg ); | |
206 | static void atari_scsi_tt_reg_write( unsigned char reg, unsigned char value); | |
207 | static unsigned char atari_scsi_falcon_reg_read( unsigned char reg ); | |
208 | static void atari_scsi_falcon_reg_write( unsigned char reg, unsigned char value ); | |
209 | ||
210 | /************************* End of Prototypes **************************/ | |
211 | ||
212 | ||
213 | static struct Scsi_Host *atari_scsi_host = NULL; | |
214 | static unsigned char (*atari_scsi_reg_read)( unsigned char reg ); | |
215 | static void (*atari_scsi_reg_write)( unsigned char reg, unsigned char value ); | |
216 | ||
217 | #ifdef REAL_DMA | |
218 | static unsigned long atari_dma_residual, atari_dma_startaddr; | |
219 | static short atari_dma_active; | |
220 | /* pointer to the dribble buffer */ | |
221 | static char *atari_dma_buffer = NULL; | |
222 | /* precalculated physical address of the dribble buffer */ | |
223 | static unsigned long atari_dma_phys_buffer; | |
224 | /* != 0 tells the Falcon int handler to copy data from the dribble buffer */ | |
225 | static char *atari_dma_orig_addr; | |
226 | /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use | |
227 | * scatter-gather anyway, so most transfers are 1024 byte only. In the rare | |
228 | * cases where requests to physical contiguous buffers have been merged, this | |
229 | * request is <= 4k (one page). So I don't think we have to split transfers | |
230 | * just due to this buffer size... | |
231 | */ | |
232 | #define STRAM_BUFFER_SIZE (4096) | |
233 | /* mask for address bits that can't be used with the ST-DMA */ | |
234 | static unsigned long atari_dma_stram_mask; | |
235 | #define STRAM_ADDR(a) (((a) & atari_dma_stram_mask) == 0) | |
236 | /* number of bytes to cut from a transfer to handle NCR overruns */ | |
237 | static int atari_read_overruns = 0; | |
238 | #endif | |
239 | ||
240 | static int setup_can_queue = -1; | |
8d3b33f6 | 241 | module_param(setup_can_queue, int, 0); |
1da177e4 | 242 | static int setup_cmd_per_lun = -1; |
8d3b33f6 | 243 | module_param(setup_cmd_per_lun, int, 0); |
1da177e4 | 244 | static int setup_sg_tablesize = -1; |
8d3b33f6 | 245 | module_param(setup_sg_tablesize, int, 0); |
1da177e4 LT |
246 | #ifdef SUPPORT_TAGS |
247 | static int setup_use_tagged_queuing = -1; | |
8d3b33f6 | 248 | module_param(setup_use_tagged_queuing, int, 0); |
1da177e4 LT |
249 | #endif |
250 | static int setup_hostid = -1; | |
8d3b33f6 | 251 | module_param(setup_hostid, int, 0); |
1da177e4 LT |
252 | |
253 | ||
254 | #if defined(CONFIG_TT_DMA_EMUL) | |
255 | #include "atari_dma_emul.c" | |
256 | #endif | |
257 | ||
258 | #if defined(REAL_DMA) | |
259 | ||
260 | static int scsi_dma_is_ignored_buserr( unsigned char dma_stat ) | |
261 | { | |
262 | int i; | |
263 | unsigned long addr = SCSI_DMA_READ_P( dma_addr ), end_addr; | |
264 | ||
265 | if (dma_stat & 0x01) { | |
266 | ||
267 | /* A bus error happens when DMA-ing from the last page of a | |
268 | * physical memory chunk (DMA prefetch!), but that doesn't hurt. | |
269 | * Check for this case: | |
270 | */ | |
271 | ||
272 | for( i = 0; i < m68k_num_memory; ++i ) { | |
273 | end_addr = m68k_memory[i].addr + | |
274 | m68k_memory[i].size; | |
275 | if (end_addr <= addr && addr <= end_addr + 4) | |
276 | return( 1 ); | |
277 | } | |
278 | } | |
279 | return( 0 ); | |
280 | } | |
281 | ||
282 | ||
283 | #if 0 | |
284 | /* Dead code... wasn't called anyway :-) and causes some trouble, because at | |
285 | * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has | |
286 | * to clear the DMA int pending bit before it allows other level 6 interrupts. | |
287 | */ | |
7d12e780 | 288 | static void scsi_dma_buserr (int irq, void *dummy) |
1da177e4 LT |
289 | { |
290 | unsigned char dma_stat = tt_scsi_dma.dma_ctrl; | |
291 | ||
292 | /* Don't do anything if a NCR interrupt is pending. Probably it's just | |
293 | * masked... */ | |
294 | if (atari_irq_pending( IRQ_TT_MFP_SCSI )) | |
295 | return; | |
296 | ||
297 | printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n", | |
298 | SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt)); | |
299 | if (dma_stat & 0x80) { | |
300 | if (!scsi_dma_is_ignored_buserr( dma_stat )) | |
301 | printk( "SCSI DMA bus error -- bad DMA programming!\n" ); | |
302 | } | |
303 | else { | |
304 | /* Under normal circumstances we never should get to this point, | |
305 | * since both interrupts are triggered simultaneously and the 5380 | |
306 | * int has higher priority. When this irq is handled, that DMA | |
307 | * interrupt is cleared. So a warning message is printed here. | |
308 | */ | |
309 | printk( "SCSI DMA intr ?? -- this shouldn't happen!\n" ); | |
310 | } | |
311 | } | |
312 | #endif | |
313 | ||
314 | #endif | |
315 | ||
316 | ||
7d12e780 | 317 | static irqreturn_t scsi_tt_intr (int irq, void *dummy) |
1da177e4 LT |
318 | { |
319 | #ifdef REAL_DMA | |
320 | int dma_stat; | |
321 | ||
322 | dma_stat = tt_scsi_dma.dma_ctrl; | |
323 | ||
324 | INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n", | |
325 | atari_scsi_host->host_no, dma_stat & 0xff); | |
326 | ||
327 | /* Look if it was the DMA that has interrupted: First possibility | |
328 | * is that a bus error occurred... | |
329 | */ | |
330 | if (dma_stat & 0x80) { | |
331 | if (!scsi_dma_is_ignored_buserr( dma_stat )) { | |
332 | printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n", | |
333 | SCSI_DMA_READ_P(dma_addr)); | |
334 | printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!"); | |
335 | } | |
336 | } | |
337 | ||
338 | /* If the DMA is active but not finished, we have the case | |
339 | * that some other 5380 interrupt occurred within the DMA transfer. | |
340 | * This means we have residual bytes, if the desired end address | |
341 | * is not yet reached. Maybe we have to fetch some bytes from the | |
342 | * rest data register, too. The residual must be calculated from | |
343 | * the address pointer, not the counter register, because only the | |
344 | * addr reg counts bytes not yet written and pending in the rest | |
345 | * data reg! | |
346 | */ | |
347 | if ((dma_stat & 0x02) && !(dma_stat & 0x40)) { | |
348 | atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P( dma_addr ) - | |
349 | atari_dma_startaddr); | |
350 | ||
351 | DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n", | |
352 | atari_dma_residual); | |
353 | ||
354 | if ((signed int)atari_dma_residual < 0) | |
355 | atari_dma_residual = 0; | |
356 | if ((dma_stat & 1) == 0) { | |
357 | /* After read operations, we maybe have to | |
358 | transport some rest bytes */ | |
359 | atari_scsi_fetch_restbytes(); | |
360 | } | |
361 | else { | |
362 | /* There seems to be a nasty bug in some SCSI-DMA/NCR | |
363 | combinations: If a target disconnects while a write | |
364 | operation is going on, the address register of the | |
365 | DMA may be a few bytes farer than it actually read. | |
366 | This is probably due to DMA prefetching and a delay | |
367 | between DMA and NCR. Experiments showed that the | |
368 | dma_addr is 9 bytes to high, but this could vary. | |
369 | The problem is, that the residual is thus calculated | |
370 | wrong and the next transfer will start behind where | |
371 | it should. So we round up the residual to the next | |
372 | multiple of a sector size, if it isn't already a | |
373 | multiple and the originally expected transfer size | |
374 | was. The latter condition is there to ensure that | |
375 | the correction is taken only for "real" data | |
376 | transfers and not for, e.g., the parameters of some | |
377 | other command. These shouldn't disconnect anyway. | |
378 | */ | |
379 | if (atari_dma_residual & 0x1ff) { | |
380 | DMA_PRINTK("SCSI DMA: DMA bug corrected, " | |
381 | "difference %ld bytes\n", | |
382 | 512 - (atari_dma_residual & 0x1ff)); | |
383 | atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff; | |
384 | } | |
385 | } | |
386 | tt_scsi_dma.dma_ctrl = 0; | |
387 | } | |
388 | ||
389 | /* If the DMA is finished, fetch the rest bytes and turn it off */ | |
390 | if (dma_stat & 0x40) { | |
391 | atari_dma_residual = 0; | |
392 | if ((dma_stat & 1) == 0) | |
393 | atari_scsi_fetch_restbytes(); | |
394 | tt_scsi_dma.dma_ctrl = 0; | |
395 | } | |
396 | ||
397 | #endif /* REAL_DMA */ | |
398 | ||
399 | NCR5380_intr (0, 0, 0); | |
400 | ||
401 | #if 0 | |
402 | /* To be sure the int is not masked */ | |
403 | atari_enable_irq( IRQ_TT_MFP_SCSI ); | |
404 | #endif | |
405 | return IRQ_HANDLED; | |
406 | } | |
407 | ||
408 | ||
7d12e780 | 409 | static irqreturn_t scsi_falcon_intr (int irq, void *dummy) |
1da177e4 LT |
410 | { |
411 | #ifdef REAL_DMA | |
412 | int dma_stat; | |
413 | ||
414 | /* Turn off DMA and select sector counter register before | |
415 | * accessing the status register (Atari recommendation!) | |
416 | */ | |
417 | st_dma.dma_mode_status = 0x90; | |
418 | dma_stat = st_dma.dma_mode_status; | |
419 | ||
420 | /* Bit 0 indicates some error in the DMA process... don't know | |
421 | * what happened exactly (no further docu). | |
422 | */ | |
423 | if (!(dma_stat & 0x01)) { | |
424 | /* DMA error */ | |
425 | printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR()); | |
426 | } | |
427 | ||
428 | /* If the DMA was active, but now bit 1 is not clear, it is some | |
429 | * other 5380 interrupt that finishes the DMA transfer. We have to | |
430 | * calculate the number of residual bytes and give a warning if | |
431 | * bytes are stuck in the ST-DMA fifo (there's no way to reach them!) | |
432 | */ | |
433 | if (atari_dma_active && (dma_stat & 0x02)) { | |
434 | unsigned long transferred; | |
435 | ||
436 | transferred = SCSI_DMA_GETADR() - atari_dma_startaddr; | |
437 | /* The ST-DMA address is incremented in 2-byte steps, but the | |
438 | * data are written only in 16-byte chunks. If the number of | |
439 | * transferred bytes is not divisible by 16, the remainder is | |
440 | * lost somewhere in outer space. | |
441 | */ | |
442 | if (transferred & 15) | |
443 | printk(KERN_ERR "SCSI DMA error: %ld bytes lost in " | |
444 | "ST-DMA fifo\n", transferred & 15); | |
445 | ||
446 | atari_dma_residual = HOSTDATA_DMALEN - transferred; | |
447 | DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n", | |
448 | atari_dma_residual); | |
449 | } | |
450 | else | |
451 | atari_dma_residual = 0; | |
452 | atari_dma_active = 0; | |
453 | ||
454 | if (atari_dma_orig_addr) { | |
455 | /* If the dribble buffer was used on a read operation, copy the DMA-ed | |
456 | * data to the original destination address. | |
457 | */ | |
458 | memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr), | |
459 | HOSTDATA_DMALEN - atari_dma_residual); | |
460 | atari_dma_orig_addr = NULL; | |
461 | } | |
462 | ||
463 | #endif /* REAL_DMA */ | |
464 | ||
465 | NCR5380_intr (0, 0, 0); | |
466 | return IRQ_HANDLED; | |
467 | } | |
468 | ||
469 | ||
470 | #ifdef REAL_DMA | |
471 | static void atari_scsi_fetch_restbytes( void ) | |
472 | { | |
473 | int nr; | |
474 | char *src, *dst; | |
475 | unsigned long phys_dst; | |
476 | ||
477 | /* fetch rest bytes in the DMA register */ | |
478 | phys_dst = SCSI_DMA_READ_P(dma_addr); | |
479 | nr = phys_dst & 3; | |
480 | if (nr) { | |
481 | /* there are 'nr' bytes left for the last long address | |
482 | before the DMA pointer */ | |
483 | phys_dst ^= nr; | |
484 | DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx", | |
485 | nr, phys_dst); | |
486 | /* The content of the DMA pointer is a physical address! */ | |
487 | dst = phys_to_virt(phys_dst); | |
488 | DMA_PRINTK(" = virt addr %p\n", dst); | |
489 | for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr) | |
490 | *dst++ = *src++; | |
491 | } | |
492 | } | |
493 | #endif /* REAL_DMA */ | |
494 | ||
495 | ||
496 | static int falcon_got_lock = 0; | |
497 | static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait); | |
498 | static int falcon_trying_lock = 0; | |
499 | static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait); | |
500 | static int falcon_dont_release = 0; | |
501 | ||
502 | /* This function releases the lock on the DMA chip if there is no | |
503 | * connected command and the disconnected queue is empty. On | |
504 | * releasing, instances of falcon_get_lock are awoken, that put | |
505 | * themselves to sleep for fairness. They can now try to get the lock | |
506 | * again (but others waiting longer more probably will win). | |
507 | */ | |
508 | ||
509 | static void | |
510 | falcon_release_lock_if_possible( struct NCR5380_hostdata * hostdata ) | |
511 | { | |
512 | unsigned long flags; | |
513 | ||
514 | if (IS_A_TT()) return; | |
515 | ||
516 | local_irq_save(flags); | |
517 | ||
518 | if (falcon_got_lock && | |
519 | !hostdata->disconnected_queue && | |
520 | !hostdata->issue_queue && | |
521 | !hostdata->connected) { | |
522 | ||
523 | if (falcon_dont_release) { | |
524 | #if 0 | |
525 | printk("WARNING: Lock release not allowed. Ignored\n"); | |
526 | #endif | |
527 | local_irq_restore(flags); | |
528 | return; | |
529 | } | |
530 | falcon_got_lock = 0; | |
531 | stdma_release(); | |
532 | wake_up( &falcon_fairness_wait ); | |
533 | } | |
534 | ||
535 | local_irq_restore(flags); | |
536 | } | |
537 | ||
538 | /* This function manages the locking of the ST-DMA. | |
539 | * If the DMA isn't locked already for SCSI, it tries to lock it by | |
540 | * calling stdma_lock(). But if the DMA is locked by the SCSI code and | |
541 | * there are other drivers waiting for the chip, we do not issue the | |
542 | * command immediately but wait on 'falcon_fairness_queue'. We will be | |
543 | * waked up when the DMA is unlocked by some SCSI interrupt. After that | |
544 | * we try to get the lock again. | |
545 | * But we must be prepared that more than one instance of | |
546 | * falcon_get_lock() is waiting on the fairness queue. They should not | |
547 | * try all at once to call stdma_lock(), one is enough! For that, the | |
548 | * first one sets 'falcon_trying_lock', others that see that variable | |
549 | * set wait on the queue 'falcon_try_wait'. | |
550 | * Complicated, complicated.... Sigh... | |
551 | */ | |
552 | ||
553 | static void falcon_get_lock( void ) | |
554 | { | |
555 | unsigned long flags; | |
556 | ||
557 | if (IS_A_TT()) return; | |
558 | ||
559 | local_irq_save(flags); | |
560 | ||
561 | while( !in_interrupt() && falcon_got_lock && stdma_others_waiting() ) | |
562 | sleep_on( &falcon_fairness_wait ); | |
563 | ||
564 | while (!falcon_got_lock) { | |
565 | if (in_interrupt()) | |
566 | panic( "Falcon SCSI hasn't ST-DMA lock in interrupt" ); | |
567 | if (!falcon_trying_lock) { | |
568 | falcon_trying_lock = 1; | |
569 | stdma_lock(scsi_falcon_intr, NULL); | |
570 | falcon_got_lock = 1; | |
571 | falcon_trying_lock = 0; | |
572 | wake_up( &falcon_try_wait ); | |
573 | } | |
574 | else { | |
575 | sleep_on( &falcon_try_wait ); | |
576 | } | |
577 | } | |
578 | ||
579 | local_irq_restore(flags); | |
580 | if (!falcon_got_lock) | |
581 | panic("Falcon SCSI: someone stole the lock :-(\n"); | |
582 | } | |
583 | ||
584 | ||
585 | /* This is the wrapper function for NCR5380_queue_command(). It just | |
586 | * tries to get the lock on the ST-DMA (see above) and then calls the | |
587 | * original function. | |
588 | */ | |
589 | ||
590 | #if 0 | |
591 | int atari_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *)) | |
592 | { | |
593 | /* falcon_get_lock(); | |
594 | * ++guenther: moved to NCR5380_queue_command() to prevent | |
595 | * race condition, see there for an explanation. | |
596 | */ | |
597 | return( NCR5380_queue_command( cmd, done ) ); | |
598 | } | |
599 | #endif | |
600 | ||
601 | ||
d0be4a7d | 602 | int atari_scsi_detect (struct scsi_host_template *host) |
1da177e4 LT |
603 | { |
604 | static int called = 0; | |
605 | struct Scsi_Host *instance; | |
606 | ||
607 | if (!MACH_IS_ATARI || | |
608 | (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) || | |
609 | called) | |
610 | return( 0 ); | |
611 | ||
612 | host->proc_name = "Atari"; | |
613 | ||
614 | atari_scsi_reg_read = IS_A_TT() ? atari_scsi_tt_reg_read : | |
615 | atari_scsi_falcon_reg_read; | |
616 | atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write : | |
617 | atari_scsi_falcon_reg_write; | |
618 | ||
619 | /* setup variables */ | |
620 | host->can_queue = | |
621 | (setup_can_queue > 0) ? setup_can_queue : | |
622 | IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE; | |
623 | host->cmd_per_lun = | |
624 | (setup_cmd_per_lun > 0) ? setup_cmd_per_lun : | |
625 | IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN; | |
626 | /* Force sg_tablesize to 0 on a Falcon! */ | |
627 | host->sg_tablesize = | |
628 | !IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE : | |
629 | (setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE; | |
630 | ||
631 | if (setup_hostid >= 0) | |
632 | host->this_id = setup_hostid; | |
633 | else { | |
634 | /* use 7 as default */ | |
635 | host->this_id = 7; | |
636 | /* Test if a host id is set in the NVRam */ | |
637 | if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) { | |
638 | unsigned char b = nvram_read_byte( 14 ); | |
639 | /* Arbitration enabled? (for TOS) If yes, use configured host ID */ | |
640 | if (b & 0x80) | |
641 | host->this_id = b & 7; | |
642 | } | |
643 | } | |
644 | ||
645 | #ifdef SUPPORT_TAGS | |
646 | if (setup_use_tagged_queuing < 0) | |
647 | setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING; | |
648 | #endif | |
649 | #ifdef REAL_DMA | |
650 | /* If running on a Falcon and if there's TT-Ram (i.e., more than one | |
651 | * memory block, since there's always ST-Ram in a Falcon), then allocate a | |
652 | * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative | |
653 | * Ram. | |
654 | */ | |
655 | if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) && | |
656 | !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) { | |
657 | atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI"); | |
658 | if (!atari_dma_buffer) { | |
659 | printk( KERN_ERR "atari_scsi_detect: can't allocate ST-RAM " | |
660 | "double buffer\n" ); | |
661 | return( 0 ); | |
662 | } | |
663 | atari_dma_phys_buffer = virt_to_phys( atari_dma_buffer ); | |
664 | atari_dma_orig_addr = 0; | |
665 | } | |
666 | #endif | |
667 | instance = scsi_register (host, sizeof (struct NCR5380_hostdata)); | |
668 | if(instance == NULL) | |
669 | { | |
670 | atari_stram_free(atari_dma_buffer); | |
671 | atari_dma_buffer = 0; | |
672 | return 0; | |
673 | } | |
674 | atari_scsi_host = instance; | |
675 | /* Set irq to 0, to avoid that the mid-level code disables our interrupt | |
676 | * during queue_command calls. This is completely unnecessary, and even | |
677 | * worse causes bad problems on the Falcon, where the int is shared with | |
678 | * IDE and floppy! */ | |
679 | instance->irq = 0; | |
680 | ||
681 | #ifdef CONFIG_ATARI_SCSI_RESET_BOOT | |
682 | atari_scsi_reset_boot(); | |
683 | #endif | |
684 | NCR5380_init (instance, 0); | |
685 | ||
686 | if (IS_A_TT()) { | |
687 | ||
688 | /* This int is actually "pseudo-slow", i.e. it acts like a slow | |
689 | * interrupt after having cleared the pending flag for the DMA | |
690 | * interrupt. */ | |
691 | if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW, | |
692 | "SCSI NCR5380", scsi_tt_intr)) { | |
693 | printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI); | |
694 | scsi_unregister(atari_scsi_host); | |
695 | atari_stram_free(atari_dma_buffer); | |
696 | atari_dma_buffer = 0; | |
697 | return 0; | |
698 | } | |
699 | tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */ | |
700 | #ifdef REAL_DMA | |
701 | tt_scsi_dma.dma_ctrl = 0; | |
702 | atari_dma_residual = 0; | |
703 | #ifdef CONFIG_TT_DMA_EMUL | |
704 | if (MACH_IS_HADES) { | |
705 | if (request_irq(IRQ_AUTO_2, hades_dma_emulator, | |
706 | IRQ_TYPE_PRIO, "Hades DMA emulator", | |
707 | hades_dma_emulator)) { | |
708 | printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting (MACH_IS_HADES)",IRQ_AUTO_2); | |
709 | free_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr); | |
710 | scsi_unregister(atari_scsi_host); | |
711 | atari_stram_free(atari_dma_buffer); | |
712 | atari_dma_buffer = 0; | |
713 | return 0; | |
714 | } | |
715 | } | |
716 | #endif | |
717 | if (MACH_IS_MEDUSA || MACH_IS_HADES) { | |
718 | /* While the read overruns (described by Drew Eckhardt in | |
719 | * NCR5380.c) never happened on TTs, they do in fact on the Medusa | |
720 | * (This was the cause why SCSI didn't work right for so long | |
721 | * there.) Since handling the overruns slows down a bit, I turned | |
722 | * the #ifdef's into a runtime condition. | |
723 | * | |
724 | * In principle it should be sufficient to do max. 1 byte with | |
725 | * PIO, but there is another problem on the Medusa with the DMA | |
726 | * rest data register. So 'atari_read_overruns' is currently set | |
727 | * to 4 to avoid having transfers that aren't a multiple of 4. If | |
728 | * the rest data bug is fixed, this can be lowered to 1. | |
729 | */ | |
730 | atari_read_overruns = 4; | |
731 | } | |
732 | #endif /*REAL_DMA*/ | |
733 | } | |
734 | else { /* ! IS_A_TT */ | |
735 | ||
736 | /* Nothing to do for the interrupt: the ST-DMA is initialized | |
737 | * already by atari_init_INTS() | |
738 | */ | |
739 | ||
740 | #ifdef REAL_DMA | |
741 | atari_dma_residual = 0; | |
742 | atari_dma_active = 0; | |
743 | atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 | |
744 | : 0xff000000); | |
745 | #endif | |
746 | } | |
747 | ||
748 | printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d " | |
749 | #ifdef SUPPORT_TAGS | |
750 | "TAGGED-QUEUING=%s " | |
751 | #endif | |
752 | "HOSTID=%d", | |
753 | instance->host_no, instance->hostt->can_queue, | |
754 | instance->hostt->cmd_per_lun, | |
755 | instance->hostt->sg_tablesize, | |
756 | #ifdef SUPPORT_TAGS | |
757 | setup_use_tagged_queuing ? "yes" : "no", | |
758 | #endif | |
759 | instance->hostt->this_id ); | |
760 | NCR5380_print_options (instance); | |
761 | printk ("\n"); | |
762 | ||
763 | called = 1; | |
764 | return( 1 ); | |
765 | } | |
766 | ||
767 | #ifdef MODULE | |
768 | int atari_scsi_release (struct Scsi_Host *sh) | |
769 | { | |
770 | if (IS_A_TT()) | |
771 | free_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr); | |
772 | if (atari_dma_buffer) | |
773 | atari_stram_free (atari_dma_buffer); | |
774 | return 1; | |
775 | } | |
776 | #endif | |
777 | ||
778 | void __init atari_scsi_setup(char *str, int *ints) | |
779 | { | |
780 | /* Format of atascsi parameter is: | |
781 | * atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
782 | * Defaults depend on TT or Falcon, hostid determined at run time. | |
783 | * Negative values mean don't change. | |
784 | */ | |
785 | ||
786 | if (ints[0] < 1) { | |
787 | printk( "atari_scsi_setup: no arguments!\n" ); | |
788 | return; | |
789 | } | |
790 | ||
791 | if (ints[0] >= 1) { | |
792 | if (ints[1] > 0) | |
793 | /* no limits on this, just > 0 */ | |
794 | setup_can_queue = ints[1]; | |
795 | } | |
796 | if (ints[0] >= 2) { | |
797 | if (ints[2] > 0) | |
798 | setup_cmd_per_lun = ints[2]; | |
799 | } | |
800 | if (ints[0] >= 3) { | |
801 | if (ints[3] >= 0) { | |
802 | setup_sg_tablesize = ints[3]; | |
803 | /* Must be <= SG_ALL (255) */ | |
804 | if (setup_sg_tablesize > SG_ALL) | |
805 | setup_sg_tablesize = SG_ALL; | |
806 | } | |
807 | } | |
808 | if (ints[0] >= 4) { | |
809 | /* Must be between 0 and 7 */ | |
810 | if (ints[4] >= 0 && ints[4] <= 7) | |
811 | setup_hostid = ints[4]; | |
812 | else if (ints[4] > 7) | |
813 | printk( "atari_scsi_setup: invalid host ID %d !\n", ints[4] ); | |
814 | } | |
815 | #ifdef SUPPORT_TAGS | |
816 | if (ints[0] >= 5) { | |
817 | if (ints[5] >= 0) | |
818 | setup_use_tagged_queuing = !!ints[5]; | |
819 | } | |
820 | #endif | |
821 | } | |
822 | ||
823 | int atari_scsi_bus_reset(Scsi_Cmnd *cmd) | |
824 | { | |
825 | int rv; | |
826 | struct NCR5380_hostdata *hostdata = | |
827 | (struct NCR5380_hostdata *)cmd->device->host->hostdata; | |
828 | ||
829 | /* For doing the reset, SCSI interrupts must be disabled first, | |
830 | * since the 5380 raises its IRQ line while _RST is active and we | |
831 | * can't disable interrupts completely, since we need the timer. | |
832 | */ | |
833 | /* And abort a maybe active DMA transfer */ | |
834 | if (IS_A_TT()) { | |
835 | atari_turnoff_irq( IRQ_TT_MFP_SCSI ); | |
836 | #ifdef REAL_DMA | |
837 | tt_scsi_dma.dma_ctrl = 0; | |
838 | #endif /* REAL_DMA */ | |
839 | } | |
840 | else { | |
841 | atari_turnoff_irq( IRQ_MFP_FSCSI ); | |
842 | #ifdef REAL_DMA | |
843 | st_dma.dma_mode_status = 0x90; | |
844 | atari_dma_active = 0; | |
845 | atari_dma_orig_addr = NULL; | |
846 | #endif /* REAL_DMA */ | |
847 | } | |
848 | ||
849 | rv = NCR5380_bus_reset(cmd); | |
850 | ||
851 | /* Re-enable ints */ | |
852 | if (IS_A_TT()) { | |
853 | atari_turnon_irq( IRQ_TT_MFP_SCSI ); | |
854 | } | |
855 | else { | |
856 | atari_turnon_irq( IRQ_MFP_FSCSI ); | |
857 | } | |
858 | if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS) | |
859 | falcon_release_lock_if_possible(hostdata); | |
860 | ||
861 | return( rv ); | |
862 | } | |
863 | ||
864 | ||
865 | #ifdef CONFIG_ATARI_SCSI_RESET_BOOT | |
866 | static void __init atari_scsi_reset_boot(void) | |
867 | { | |
868 | unsigned long end; | |
869 | ||
870 | /* | |
871 | * Do a SCSI reset to clean up the bus during initialization. No messing | |
872 | * with the queues, interrupts, or locks necessary here. | |
873 | */ | |
874 | ||
875 | printk( "Atari SCSI: resetting the SCSI bus..." ); | |
876 | ||
877 | /* get in phase */ | |
878 | NCR5380_write( TARGET_COMMAND_REG, | |
879 | PHASE_SR_TO_TCR( NCR5380_read(STATUS_REG) )); | |
880 | ||
881 | /* assert RST */ | |
882 | NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST ); | |
883 | /* The min. reset hold time is 25us, so 40us should be enough */ | |
884 | udelay( 50 ); | |
885 | /* reset RST and interrupt */ | |
886 | NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE ); | |
887 | NCR5380_read( RESET_PARITY_INTERRUPT_REG ); | |
888 | ||
889 | end = jiffies + AFTER_RESET_DELAY; | |
890 | while (time_before(jiffies, end)) | |
891 | barrier(); | |
892 | ||
893 | printk( " done\n" ); | |
894 | } | |
895 | #endif | |
896 | ||
897 | ||
898 | const char * atari_scsi_info (struct Scsi_Host *host) | |
899 | { | |
900 | /* atari_scsi_detect() is verbose enough... */ | |
901 | static const char string[] = "Atari native SCSI"; | |
902 | return string; | |
903 | } | |
904 | ||
905 | ||
906 | #if defined(REAL_DMA) | |
907 | ||
908 | unsigned long atari_scsi_dma_setup( struct Scsi_Host *instance, void *data, | |
909 | unsigned long count, int dir ) | |
910 | { | |
911 | unsigned long addr = virt_to_phys( data ); | |
912 | ||
913 | DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, " | |
914 | "dir = %d\n", instance->host_no, data, addr, count, dir); | |
915 | ||
916 | if (!IS_A_TT() && !STRAM_ADDR(addr)) { | |
917 | /* If we have a non-DMAable address on a Falcon, use the dribble | |
918 | * buffer; 'orig_addr' != 0 in the read case tells the interrupt | |
919 | * handler to copy data from the dribble buffer to the originally | |
920 | * wanted address. | |
921 | */ | |
922 | if (dir) | |
923 | memcpy( atari_dma_buffer, data, count ); | |
924 | else | |
925 | atari_dma_orig_addr = data; | |
926 | addr = atari_dma_phys_buffer; | |
927 | } | |
928 | ||
929 | atari_dma_startaddr = addr; /* Needed for calculating residual later. */ | |
930 | ||
931 | /* Cache cleanup stuff: On writes, push any dirty cache out before sending | |
932 | * it to the peripheral. (Must be done before DMA setup, since at least | |
933 | * the ST-DMA begins to fill internal buffers right after setup. For | |
934 | * reads, invalidate any cache, may be altered after DMA without CPU | |
935 | * knowledge. | |
936 | * | |
937 | * ++roman: For the Medusa, there's no need at all for that cache stuff, | |
938 | * because the hardware does bus snooping (fine!). | |
939 | */ | |
940 | dma_cache_maintenance( addr, count, dir ); | |
941 | ||
942 | if (count == 0) | |
943 | printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n"); | |
944 | ||
945 | if (IS_A_TT()) { | |
946 | tt_scsi_dma.dma_ctrl = dir; | |
947 | SCSI_DMA_WRITE_P( dma_addr, addr ); | |
948 | SCSI_DMA_WRITE_P( dma_cnt, count ); | |
949 | tt_scsi_dma.dma_ctrl = dir | 2; | |
950 | } | |
951 | else { /* ! IS_A_TT */ | |
952 | ||
953 | /* set address */ | |
954 | SCSI_DMA_SETADR( addr ); | |
955 | ||
956 | /* toggle direction bit to clear FIFO and set DMA direction */ | |
957 | dir <<= 8; | |
958 | st_dma.dma_mode_status = 0x90 | dir; | |
959 | st_dma.dma_mode_status = 0x90 | (dir ^ 0x100); | |
960 | st_dma.dma_mode_status = 0x90 | dir; | |
961 | udelay(40); | |
962 | /* On writes, round up the transfer length to the next multiple of 512 | |
963 | * (see also comment at atari_dma_xfer_len()). */ | |
964 | st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9; | |
965 | udelay(40); | |
966 | st_dma.dma_mode_status = 0x10 | dir; | |
967 | udelay(40); | |
968 | /* need not restore value of dir, only boolean value is tested */ | |
969 | atari_dma_active = 1; | |
970 | } | |
971 | ||
972 | return( count ); | |
973 | } | |
974 | ||
975 | ||
976 | static long atari_scsi_dma_residual( struct Scsi_Host *instance ) | |
977 | { | |
978 | return( atari_dma_residual ); | |
979 | } | |
980 | ||
981 | ||
982 | #define CMD_SURELY_BLOCK_MODE 0 | |
983 | #define CMD_SURELY_BYTE_MODE 1 | |
984 | #define CMD_MODE_UNKNOWN 2 | |
985 | ||
986 | static int falcon_classify_cmd( Scsi_Cmnd *cmd ) | |
987 | { | |
988 | unsigned char opcode = cmd->cmnd[0]; | |
989 | ||
990 | if (opcode == READ_DEFECT_DATA || opcode == READ_LONG || | |
991 | opcode == READ_BUFFER) | |
992 | return( CMD_SURELY_BYTE_MODE ); | |
993 | else if (opcode == READ_6 || opcode == READ_10 || | |
994 | opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE || | |
995 | opcode == RECOVER_BUFFERED_DATA) { | |
996 | /* In case of a sequential-access target (tape), special care is | |
997 | * needed here: The transfer is block-mode only if the 'fixed' bit is | |
998 | * set! */ | |
999 | if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1)) | |
1000 | return( CMD_SURELY_BYTE_MODE ); | |
1001 | else | |
1002 | return( CMD_SURELY_BLOCK_MODE ); | |
1003 | } | |
1004 | else | |
1005 | return( CMD_MODE_UNKNOWN ); | |
1006 | } | |
1007 | ||
1008 | ||
1009 | /* This function calculates the number of bytes that can be transferred via | |
1010 | * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the | |
1011 | * ST-DMA chip. There are only multiples of 512 bytes possible and max. | |
1012 | * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not | |
1013 | * possible on the Falcon, since that would require to program the DMA for | |
1014 | * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have | |
1015 | * the overrun problem, so this question is academic :-) | |
1016 | */ | |
1017 | ||
1018 | static unsigned long atari_dma_xfer_len( unsigned long wanted_len, | |
1019 | Scsi_Cmnd *cmd, | |
1020 | int write_flag ) | |
1021 | { | |
1022 | unsigned long possible_len, limit; | |
1023 | #ifndef CONFIG_TT_DMA_EMUL | |
1024 | if (MACH_IS_HADES) | |
1025 | /* Hades has no SCSI DMA at all :-( Always force use of PIO */ | |
1026 | return( 0 ); | |
1027 | #endif | |
1028 | if (IS_A_TT()) | |
1029 | /* TT SCSI DMA can transfer arbitrary #bytes */ | |
1030 | return( wanted_len ); | |
1031 | ||
1032 | /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max. | |
1033 | * 255*512 bytes, but this should be enough) | |
1034 | * | |
1035 | * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands | |
1036 | * that return a number of bytes which cannot be known beforehand. In this | |
1037 | * case, the given transfer length is an "allocation length". Now it | |
1038 | * can happen that this allocation length is a multiple of 512 bytes and | |
1039 | * the DMA is used. But if not n*512 bytes really arrive, some input data | |
1040 | * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish | |
1041 | * between commands that do block transfers and those that do byte | |
1042 | * transfers. But this isn't easy... there are lots of vendor specific | |
1043 | * commands, and the user can issue any command via the | |
1044 | * SCSI_IOCTL_SEND_COMMAND. | |
1045 | * | |
1046 | * The solution: We classify SCSI commands in 1) surely block-mode cmd.s, | |
1047 | * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1) | |
1048 | * and 3), the thing to do is obvious: allow any number of blocks via DMA | |
1049 | * or none. In case 2), we apply some heuristic: Byte mode is assumed if | |
1050 | * the transfer (allocation) length is < 1024, hoping that no cmd. not | |
1051 | * explicitly known as byte mode have such big allocation lengths... | |
1052 | * BTW, all the discussion above applies only to reads. DMA writes are | |
1053 | * unproblematic anyways, since the targets aborts the transfer after | |
1054 | * receiving a sufficient number of bytes. | |
1055 | * | |
1056 | * Another point: If the transfer is from/to an non-ST-RAM address, we | |
1057 | * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes. | |
1058 | */ | |
1059 | ||
1060 | if (write_flag) { | |
1061 | /* Write operation can always use the DMA, but the transfer size must | |
1062 | * be rounded up to the next multiple of 512 (atari_dma_setup() does | |
1063 | * this). | |
1064 | */ | |
1065 | possible_len = wanted_len; | |
1066 | } | |
1067 | else { | |
1068 | /* Read operations: if the wanted transfer length is not a multiple of | |
1069 | * 512, we cannot use DMA, since the ST-DMA cannot split transfers | |
1070 | * (no interrupt on DMA finished!) | |
1071 | */ | |
1072 | if (wanted_len & 0x1ff) | |
1073 | possible_len = 0; | |
1074 | else { | |
1075 | /* Now classify the command (see above) and decide whether it is | |
1076 | * allowed to do DMA at all */ | |
1077 | switch( falcon_classify_cmd( cmd )) { | |
1078 | case CMD_SURELY_BLOCK_MODE: | |
1079 | possible_len = wanted_len; | |
1080 | break; | |
1081 | case CMD_SURELY_BYTE_MODE: | |
1082 | possible_len = 0; /* DMA prohibited */ | |
1083 | break; | |
1084 | case CMD_MODE_UNKNOWN: | |
1085 | default: | |
1086 | /* For unknown commands assume block transfers if the transfer | |
1087 | * size/allocation length is >= 1024 */ | |
1088 | possible_len = (wanted_len < 1024) ? 0 : wanted_len; | |
1089 | break; | |
1090 | } | |
1091 | } | |
1092 | } | |
1093 | ||
1094 | /* Last step: apply the hard limit on DMA transfers */ | |
1095 | limit = (atari_dma_buffer && !STRAM_ADDR( virt_to_phys(cmd->SCp.ptr) )) ? | |
1096 | STRAM_BUFFER_SIZE : 255*512; | |
1097 | if (possible_len > limit) | |
1098 | possible_len = limit; | |
1099 | ||
1100 | if (possible_len != wanted_len) | |
1101 | DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes " | |
1102 | "instead of %ld\n", possible_len, wanted_len); | |
1103 | ||
1104 | return( possible_len ); | |
1105 | } | |
1106 | ||
1107 | ||
1108 | #endif /* REAL_DMA */ | |
1109 | ||
1110 | ||
1111 | /* NCR5380 register access functions | |
1112 | * | |
1113 | * There are separate functions for TT and Falcon, because the access | |
1114 | * methods are quite different. The calling macros NCR5380_read and | |
1115 | * NCR5380_write call these functions via function pointers. | |
1116 | */ | |
1117 | ||
1118 | static unsigned char atari_scsi_tt_reg_read( unsigned char reg ) | |
1119 | { | |
1120 | return( tt_scsi_regp[reg * 2] ); | |
1121 | } | |
1122 | ||
1123 | static void atari_scsi_tt_reg_write( unsigned char reg, unsigned char value ) | |
1124 | { | |
1125 | tt_scsi_regp[reg * 2] = value; | |
1126 | } | |
1127 | ||
1128 | static unsigned char atari_scsi_falcon_reg_read( unsigned char reg ) | |
1129 | { | |
1130 | dma_wd.dma_mode_status= (u_short)(0x88 + reg); | |
1131 | return( (u_char)dma_wd.fdc_acces_seccount ); | |
1132 | } | |
1133 | ||
1134 | static void atari_scsi_falcon_reg_write( unsigned char reg, unsigned char value ) | |
1135 | { | |
1136 | dma_wd.dma_mode_status = (u_short)(0x88 + reg); | |
1137 | dma_wd.fdc_acces_seccount = (u_short)value; | |
1138 | } | |
1139 | ||
1140 | ||
1141 | #include "atari_NCR5380.c" | |
1142 | ||
d0be4a7d | 1143 | static struct scsi_host_template driver_template = { |
1da177e4 LT |
1144 | .proc_info = atari_scsi_proc_info, |
1145 | .name = "Atari native SCSI", | |
1146 | .detect = atari_scsi_detect, | |
1147 | .release = atari_scsi_release, | |
1148 | .info = atari_scsi_info, | |
1149 | .queuecommand = atari_scsi_queue_command, | |
1150 | .eh_abort_handler = atari_scsi_abort, | |
1151 | .eh_bus_reset_handler = atari_scsi_bus_reset, | |
1152 | .can_queue = 0, /* initialized at run-time */ | |
1153 | .this_id = 0, /* initialized at run-time */ | |
1154 | .sg_tablesize = 0, /* initialized at run-time */ | |
1155 | .cmd_per_lun = 0, /* initialized at run-time */ | |
1156 | .use_clustering = DISABLE_CLUSTERING | |
1157 | }; | |
1158 | ||
1159 | ||
1160 | #include "scsi_module.c" | |
1161 | ||
1162 | MODULE_LICENSE("GPL"); |