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1 | /* sun3_NCR5380.c -- adapted from atari_NCR5380.c for the sun3 by |
2 | Sam Creasey. */ | |
3 | /* | |
4 | * NCR 5380 generic driver routines. These should make it *trivial* | |
5 | * to implement 5380 SCSI drivers under Linux with a non-trantor | |
6 | * architecture. | |
7 | * | |
8 | * Note that these routines also work with NR53c400 family chips. | |
9 | * | |
10 | * Copyright 1993, Drew Eckhardt | |
11 | * Visionary Computing | |
12 | * (Unix and Linux consulting and custom programming) | |
13 | * drew@colorado.edu | |
14 | * +1 (303) 666-5836 | |
15 | * | |
16 | * DISTRIBUTION RELEASE 6. | |
17 | * | |
18 | * For more information, please consult | |
19 | * | |
20 | * NCR 5380 Family | |
21 | * SCSI Protocol Controller | |
22 | * Databook | |
23 | * | |
24 | * NCR Microelectronics | |
25 | * 1635 Aeroplaza Drive | |
26 | * Colorado Springs, CO 80916 | |
27 | * 1+ (719) 578-3400 | |
28 | * 1+ (800) 334-5454 | |
29 | */ | |
30 | ||
31 | /* | |
32 | * ++roman: To port the 5380 driver to the Atari, I had to do some changes in | |
33 | * this file, too: | |
34 | * | |
35 | * - Some of the debug statements were incorrect (undefined variables and the | |
36 | * like). I fixed that. | |
37 | * | |
38 | * - In information_transfer(), I think a #ifdef was wrong. Looking at the | |
39 | * possible DMA transfer size should also happen for REAL_DMA. I added this | |
40 | * in the #if statement. | |
41 | * | |
42 | * - When using real DMA, information_transfer() should return in a DATAOUT | |
43 | * phase after starting the DMA. It has nothing more to do. | |
44 | * | |
45 | * - The interrupt service routine should run main after end of DMA, too (not | |
46 | * only after RESELECTION interrupts). Additionally, it should _not_ test | |
47 | * for more interrupts after running main, since a DMA process may have | |
48 | * been started and interrupts are turned on now. The new int could happen | |
49 | * inside the execution of NCR5380_intr(), leading to recursive | |
50 | * calls. | |
51 | * | |
52 | * - I've added a function merge_contiguous_buffers() that tries to | |
53 | * merge scatter-gather buffers that are located at contiguous | |
54 | * physical addresses and can be processed with the same DMA setup. | |
55 | * Since most scatter-gather operations work on a page (4K) of | |
56 | * 4 buffers (1K), in more than 90% of all cases three interrupts and | |
57 | * DMA setup actions are saved. | |
58 | * | |
59 | * - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA | |
60 | * and USLEEP, because these were messing up readability and will never be | |
61 | * needed for Atari SCSI. | |
62 | * | |
63 | * - I've revised the NCR5380_main() calling scheme (relax the 'main_running' | |
64 | * stuff), and 'main' is executed in a bottom half if awoken by an | |
65 | * interrupt. | |
66 | * | |
67 | * - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..." | |
68 | * constructs. In my eyes, this made the source rather unreadable, so I | |
69 | * finally replaced that by the *_PRINTK() macros. | |
70 | * | |
71 | */ | |
72 | ||
73 | /* | |
74 | * Further development / testing that should be done : | |
75 | * 1. Test linked command handling code after Eric is ready with | |
76 | * the high level code. | |
77 | */ | |
78 | ||
79 | #if (NDEBUG & NDEBUG_LISTS) | |
80 | #define LIST(x,y) \ | |
81 | { printk("LINE:%d Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); \ | |
82 | if ((x)==(y)) udelay(5); } | |
83 | #define REMOVE(w,x,y,z) \ | |
84 | { printk("LINE:%d Removing: %p->%p %p->%p \n", __LINE__, \ | |
85 | (void*)(w), (void*)(x), (void*)(y), (void*)(z)); \ | |
86 | if ((x)==(y)) udelay(5); } | |
87 | #else | |
88 | #define LIST(x,y) | |
89 | #define REMOVE(w,x,y,z) | |
90 | #endif | |
91 | ||
92 | #ifndef notyet | |
93 | #undef LINKED | |
94 | #endif | |
95 | ||
96 | /* | |
97 | * Design | |
98 | * Issues : | |
99 | * | |
100 | * The other Linux SCSI drivers were written when Linux was Intel PC-only, | |
101 | * and specifically for each board rather than each chip. This makes their | |
102 | * adaptation to platforms like the Mac (Some of which use NCR5380's) | |
103 | * more difficult than it has to be. | |
104 | * | |
105 | * Also, many of the SCSI drivers were written before the command queuing | |
106 | * routines were implemented, meaning their implementations of queued | |
107 | * commands were hacked on rather than designed in from the start. | |
108 | * | |
109 | * When I designed the Linux SCSI drivers I figured that | |
110 | * while having two different SCSI boards in a system might be useful | |
111 | * for debugging things, two of the same type wouldn't be used. | |
112 | * Well, I was wrong and a number of users have mailed me about running | |
113 | * multiple high-performance SCSI boards in a server. | |
114 | * | |
115 | * Finally, when I get questions from users, I have no idea what | |
116 | * revision of my driver they are running. | |
117 | * | |
118 | * This driver attempts to address these problems : | |
119 | * This is a generic 5380 driver. To use it on a different platform, | |
120 | * one simply writes appropriate system specific macros (ie, data | |
121 | * transfer - some PC's will use the I/O bus, 68K's must use | |
122 | * memory mapped) and drops this file in their 'C' wrapper. | |
123 | * | |
124 | * As far as command queueing, two queues are maintained for | |
125 | * each 5380 in the system - commands that haven't been issued yet, | |
126 | * and commands that are currently executing. This means that an | |
127 | * unlimited number of commands may be queued, letting | |
128 | * more commands propagate from the higher driver levels giving higher | |
129 | * throughput. Note that both I_T_L and I_T_L_Q nexuses are supported, | |
130 | * allowing multiple commands to propagate all the way to a SCSI-II device | |
131 | * while a command is already executing. | |
132 | * | |
133 | * To solve the multiple-boards-in-the-same-system problem, | |
134 | * there is a separate instance structure for each instance | |
135 | * of a 5380 in the system. So, multiple NCR5380 drivers will | |
136 | * be able to coexist with appropriate changes to the high level | |
137 | * SCSI code. | |
138 | * | |
139 | * A NCR5380_PUBLIC_REVISION macro is provided, with the release | |
140 | * number (updated for each public release) printed by the | |
141 | * NCR5380_print_options command, which should be called from the | |
142 | * wrapper detect function, so that I know what release of the driver | |
143 | * users are using. | |
144 | * | |
145 | * Issues specific to the NCR5380 : | |
146 | * | |
147 | * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead | |
148 | * piece of hardware that requires you to sit in a loop polling for | |
149 | * the REQ signal as long as you are connected. Some devices are | |
150 | * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect | |
151 | * while doing long seek operations. | |
152 | * | |
153 | * The workaround for this is to keep track of devices that have | |
154 | * disconnected. If the device hasn't disconnected, for commands that | |
155 | * should disconnect, we do something like | |
156 | * | |
157 | * while (!REQ is asserted) { sleep for N usecs; poll for M usecs } | |
158 | * | |
159 | * Some tweaking of N and M needs to be done. An algorithm based | |
160 | * on "time to data" would give the best results as long as short time | |
161 | * to datas (ie, on the same track) were considered, however these | |
162 | * broken devices are the exception rather than the rule and I'd rather | |
163 | * spend my time optimizing for the normal case. | |
164 | * | |
165 | * Architecture : | |
166 | * | |
167 | * At the heart of the design is a coroutine, NCR5380_main, | |
168 | * which is started when not running by the interrupt handler, | |
169 | * timer, and queue command function. It attempts to establish | |
170 | * I_T_L or I_T_L_Q nexuses by removing the commands from the | |
171 | * issue queue and calling NCR5380_select() if a nexus | |
172 | * is not established. | |
173 | * | |
174 | * Once a nexus is established, the NCR5380_information_transfer() | |
175 | * phase goes through the various phases as instructed by the target. | |
176 | * if the target goes into MSG IN and sends a DISCONNECT message, | |
177 | * the command structure is placed into the per instance disconnected | |
178 | * queue, and NCR5380_main tries to find more work. If USLEEP | |
179 | * was defined, and the target is idle for too long, the system | |
180 | * will try to sleep. | |
181 | * | |
182 | * If a command has disconnected, eventually an interrupt will trigger, | |
183 | * calling NCR5380_intr() which will in turn call NCR5380_reselect | |
184 | * to reestablish a nexus. This will run main if necessary. | |
185 | * | |
186 | * On command termination, the done function will be called as | |
187 | * appropriate. | |
188 | * | |
189 | * SCSI pointers are maintained in the SCp field of SCSI command | |
190 | * structures, being initialized after the command is connected | |
191 | * in NCR5380_select, and set as appropriate in NCR5380_information_transfer. | |
192 | * Note that in violation of the standard, an implicit SAVE POINTERS operation | |
193 | * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS. | |
194 | */ | |
195 | ||
196 | /* | |
197 | * Using this file : | |
198 | * This file a skeleton Linux SCSI driver for the NCR 5380 series | |
199 | * of chips. To use it, you write an architecture specific functions | |
200 | * and macros and include this file in your driver. | |
201 | * | |
202 | * These macros control options : | |
203 | * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically | |
204 | * for commands that return with a CHECK CONDITION status. | |
205 | * | |
206 | * LINKED - if defined, linked commands are supported. | |
207 | * | |
208 | * REAL_DMA - if defined, REAL DMA is used during the data transfer phases. | |
209 | * | |
210 | * SUPPORT_TAGS - if defined, SCSI-2 tagged queuing is used where possible | |
211 | * | |
212 | * These macros MUST be defined : | |
213 | * | |
214 | * NCR5380_read(register) - read from the specified register | |
215 | * | |
216 | * NCR5380_write(register, value) - write to the specific register | |
217 | * | |
218 | * Either real DMA *or* pseudo DMA may be implemented | |
219 | * REAL functions : | |
220 | * NCR5380_REAL_DMA should be defined if real DMA is to be used. | |
221 | * Note that the DMA setup functions should return the number of bytes | |
222 | * that they were able to program the controller for. | |
223 | * | |
224 | * Also note that generic i386/PC versions of these macros are | |
225 | * available as NCR5380_i386_dma_write_setup, | |
226 | * NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual. | |
227 | * | |
228 | * NCR5380_dma_write_setup(instance, src, count) - initialize | |
229 | * NCR5380_dma_read_setup(instance, dst, count) - initialize | |
230 | * NCR5380_dma_residual(instance); - residual count | |
231 | * | |
232 | * PSEUDO functions : | |
233 | * NCR5380_pwrite(instance, src, count) | |
234 | * NCR5380_pread(instance, dst, count); | |
235 | * | |
236 | * If nothing specific to this implementation needs doing (ie, with external | |
237 | * hardware), you must also define | |
238 | * | |
239 | * NCR5380_queue_command | |
240 | * NCR5380_reset | |
241 | * NCR5380_abort | |
242 | * NCR5380_proc_info | |
243 | * | |
244 | * to be the global entry points into the specific driver, ie | |
245 | * #define NCR5380_queue_command t128_queue_command. | |
246 | * | |
247 | * If this is not done, the routines will be defined as static functions | |
248 | * with the NCR5380* names and the user must provide a globally | |
249 | * accessible wrapper function. | |
250 | * | |
251 | * The generic driver is initialized by calling NCR5380_init(instance), | |
252 | * after setting the appropriate host specific fields and ID. If the | |
253 | * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance, | |
254 | * possible) function may be used. Before the specific driver initialization | |
255 | * code finishes, NCR5380_print_options should be called. | |
256 | */ | |
257 | ||
258 | static struct Scsi_Host *first_instance = NULL; | |
259 | static Scsi_Host_Template *the_template = NULL; | |
260 | ||
261 | /* Macros ease life... :-) */ | |
262 | #define SETUP_HOSTDATA(in) \ | |
263 | struct NCR5380_hostdata *hostdata = \ | |
264 | (struct NCR5380_hostdata *)(in)->hostdata | |
265 | #define HOSTDATA(in) ((struct NCR5380_hostdata *)(in)->hostdata) | |
266 | ||
267 | #define NEXT(cmd) ((Scsi_Cmnd *)((cmd)->host_scribble)) | |
268 | #define NEXTADDR(cmd) ((Scsi_Cmnd **)&((cmd)->host_scribble)) | |
269 | ||
270 | #define HOSTNO instance->host_no | |
271 | #define H_NO(cmd) (cmd)->device->host->host_no | |
272 | ||
273 | #define SGADDR(buffer) (void *)(((unsigned long)page_address((buffer)->page)) + \ | |
274 | (buffer)->offset) | |
275 | ||
276 | #ifdef SUPPORT_TAGS | |
277 | ||
278 | /* | |
279 | * Functions for handling tagged queuing | |
280 | * ===================================== | |
281 | * | |
282 | * ++roman (01/96): Now I've implemented SCSI-2 tagged queuing. Some notes: | |
283 | * | |
284 | * Using consecutive numbers for the tags is no good idea in my eyes. There | |
285 | * could be wrong re-usings if the counter (8 bit!) wraps and some early | |
286 | * command has been preempted for a long time. My solution: a bitfield for | |
287 | * remembering used tags. | |
288 | * | |
289 | * There's also the problem that each target has a certain queue size, but we | |
290 | * cannot know it in advance :-( We just see a QUEUE_FULL status being | |
291 | * returned. So, in this case, the driver internal queue size assumption is | |
292 | * reduced to the number of active tags if QUEUE_FULL is returned by the | |
293 | * target. The command is returned to the mid-level, but with status changed | |
294 | * to BUSY, since --as I've seen-- the mid-level can't handle QUEUE_FULL | |
295 | * correctly. | |
296 | * | |
297 | * We're also not allowed running tagged commands as long as an untagged | |
298 | * command is active. And REQUEST SENSE commands after a contingent allegiance | |
299 | * condition _must_ be untagged. To keep track whether an untagged command has | |
300 | * been issued, the host->busy array is still employed, as it is without | |
301 | * support for tagged queuing. | |
302 | * | |
303 | * One could suspect that there are possible race conditions between | |
304 | * is_lun_busy(), cmd_get_tag() and cmd_free_tag(). But I think this isn't the | |
305 | * case: is_lun_busy() and cmd_get_tag() are both called from NCR5380_main(), | |
306 | * which already guaranteed to be running at most once. It is also the only | |
307 | * place where tags/LUNs are allocated. So no other allocation can slip | |
308 | * between that pair, there could only happen a reselection, which can free a | |
309 | * tag, but that doesn't hurt. Only the sequence in cmd_free_tag() becomes | |
310 | * important: the tag bit must be cleared before 'nr_allocated' is decreased. | |
311 | */ | |
312 | ||
313 | /* -1 for TAG_NONE is not possible with unsigned char cmd->tag */ | |
314 | #undef TAG_NONE | |
315 | #define TAG_NONE 0xff | |
316 | ||
317 | /* For the m68k, the number of bits in 'allocated' must be a multiple of 32! */ | |
318 | #if (MAX_TAGS % 32) != 0 | |
319 | #error "MAX_TAGS must be a multiple of 32!" | |
320 | #endif | |
321 | ||
322 | typedef struct { | |
323 | char allocated[MAX_TAGS/8]; | |
324 | int nr_allocated; | |
325 | int queue_size; | |
326 | } TAG_ALLOC; | |
327 | ||
328 | static TAG_ALLOC TagAlloc[8][8]; /* 8 targets and 8 LUNs */ | |
329 | ||
330 | ||
331 | static void __init init_tags( void ) | |
332 | { | |
333 | int target, lun; | |
334 | TAG_ALLOC *ta; | |
335 | ||
336 | if (!setup_use_tagged_queuing) | |
337 | return; | |
338 | ||
339 | for( target = 0; target < 8; ++target ) { | |
340 | for( lun = 0; lun < 8; ++lun ) { | |
341 | ta = &TagAlloc[target][lun]; | |
342 | memset( &ta->allocated, 0, MAX_TAGS/8 ); | |
343 | ta->nr_allocated = 0; | |
344 | /* At the beginning, assume the maximum queue size we could | |
345 | * support (MAX_TAGS). This value will be decreased if the target | |
346 | * returns QUEUE_FULL status. | |
347 | */ | |
348 | ta->queue_size = MAX_TAGS; | |
349 | } | |
350 | } | |
351 | } | |
352 | ||
353 | ||
354 | /* Check if we can issue a command to this LUN: First see if the LUN is marked | |
355 | * busy by an untagged command. If the command should use tagged queuing, also | |
356 | * check that there is a free tag and the target's queue won't overflow. This | |
357 | * function should be called with interrupts disabled to avoid race | |
358 | * conditions. | |
359 | */ | |
360 | ||
361 | static int is_lun_busy( Scsi_Cmnd *cmd, int should_be_tagged ) | |
362 | { | |
363 | SETUP_HOSTDATA(cmd->device->host); | |
364 | ||
365 | if (hostdata->busy[cmd->device->id] & (1 << cmd->device->lun)) | |
366 | return( 1 ); | |
367 | if (!should_be_tagged || | |
368 | !setup_use_tagged_queuing || !cmd->device->tagged_supported) | |
369 | return( 0 ); | |
370 | if (TagAlloc[cmd->device->id][cmd->device->lun].nr_allocated >= | |
371 | TagAlloc[cmd->device->id][cmd->device->lun].queue_size ) { | |
372 | TAG_PRINTK( "scsi%d: target %d lun %d: no free tags\n", | |
373 | H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
374 | return( 1 ); | |
375 | } | |
376 | return( 0 ); | |
377 | } | |
378 | ||
379 | ||
380 | /* Allocate a tag for a command (there are no checks anymore, check_lun_busy() | |
381 | * must be called before!), or reserve the LUN in 'busy' if the command is | |
382 | * untagged. | |
383 | */ | |
384 | ||
385 | static void cmd_get_tag( Scsi_Cmnd *cmd, int should_be_tagged ) | |
386 | { | |
387 | SETUP_HOSTDATA(cmd->device->host); | |
388 | ||
389 | /* If we or the target don't support tagged queuing, allocate the LUN for | |
390 | * an untagged command. | |
391 | */ | |
392 | if (!should_be_tagged || | |
393 | !setup_use_tagged_queuing || !cmd->device->tagged_supported) { | |
394 | cmd->tag = TAG_NONE; | |
395 | hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun); | |
396 | TAG_PRINTK( "scsi%d: target %d lun %d now allocated by untagged " | |
397 | "command\n", H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
398 | } | |
399 | else { | |
400 | TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun]; | |
401 | ||
402 | cmd->tag = find_first_zero_bit( &ta->allocated, MAX_TAGS ); | |
403 | set_bit( cmd->tag, &ta->allocated ); | |
404 | ta->nr_allocated++; | |
405 | TAG_PRINTK( "scsi%d: using tag %d for target %d lun %d " | |
406 | "(now %d tags in use)\n", | |
407 | H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun, | |
408 | ta->nr_allocated ); | |
409 | } | |
410 | } | |
411 | ||
412 | ||
413 | /* Mark the tag of command 'cmd' as free, or in case of an untagged command, | |
414 | * unlock the LUN. | |
415 | */ | |
416 | ||
417 | static void cmd_free_tag( Scsi_Cmnd *cmd ) | |
418 | { | |
419 | SETUP_HOSTDATA(cmd->device->host); | |
420 | ||
421 | if (cmd->tag == TAG_NONE) { | |
422 | hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun); | |
423 | TAG_PRINTK( "scsi%d: target %d lun %d untagged cmd finished\n", | |
424 | H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
425 | } | |
426 | else if (cmd->tag >= MAX_TAGS) { | |
427 | printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!\n", | |
428 | H_NO(cmd), cmd->tag ); | |
429 | } | |
430 | else { | |
431 | TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun]; | |
432 | clear_bit( cmd->tag, &ta->allocated ); | |
433 | ta->nr_allocated--; | |
434 | TAG_PRINTK( "scsi%d: freed tag %d for target %d lun %d\n", | |
435 | H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun ); | |
436 | } | |
437 | } | |
438 | ||
439 | ||
440 | static void free_all_tags( void ) | |
441 | { | |
442 | int target, lun; | |
443 | TAG_ALLOC *ta; | |
444 | ||
445 | if (!setup_use_tagged_queuing) | |
446 | return; | |
447 | ||
448 | for( target = 0; target < 8; ++target ) { | |
449 | for( lun = 0; lun < 8; ++lun ) { | |
450 | ta = &TagAlloc[target][lun]; | |
451 | memset( &ta->allocated, 0, MAX_TAGS/8 ); | |
452 | ta->nr_allocated = 0; | |
453 | } | |
454 | } | |
455 | } | |
456 | ||
457 | #endif /* SUPPORT_TAGS */ | |
458 | ||
459 | ||
460 | /* | |
461 | * Function: void merge_contiguous_buffers( Scsi_Cmnd *cmd ) | |
462 | * | |
463 | * Purpose: Try to merge several scatter-gather requests into one DMA | |
464 | * transfer. This is possible if the scatter buffers lie on | |
465 | * physical contiguous addresses. | |
466 | * | |
467 | * Parameters: Scsi_Cmnd *cmd | |
468 | * The command to work on. The first scatter buffer's data are | |
469 | * assumed to be already transfered into ptr/this_residual. | |
470 | */ | |
471 | ||
472 | static void merge_contiguous_buffers( Scsi_Cmnd *cmd ) | |
473 | { | |
474 | unsigned long endaddr; | |
475 | #if (NDEBUG & NDEBUG_MERGING) | |
476 | unsigned long oldlen = cmd->SCp.this_residual; | |
477 | int cnt = 1; | |
478 | #endif | |
479 | ||
480 | for (endaddr = virt_to_phys(cmd->SCp.ptr + cmd->SCp.this_residual - 1) + 1; | |
481 | cmd->SCp.buffers_residual && | |
482 | virt_to_phys(SGADDR(&(cmd->SCp.buffer[1]))) == endaddr; ) { | |
483 | ||
484 | MER_PRINTK("VTOP(%p) == %08lx -> merging\n", | |
485 | SGADDR(&(cmd->SCp.buffer[1])), endaddr); | |
486 | #if (NDEBUG & NDEBUG_MERGING) | |
487 | ++cnt; | |
488 | #endif | |
489 | ++cmd->SCp.buffer; | |
490 | --cmd->SCp.buffers_residual; | |
491 | cmd->SCp.this_residual += cmd->SCp.buffer->length; | |
492 | endaddr += cmd->SCp.buffer->length; | |
493 | } | |
494 | #if (NDEBUG & NDEBUG_MERGING) | |
495 | if (oldlen != cmd->SCp.this_residual) | |
496 | MER_PRINTK("merged %d buffers from %p, new length %08x\n", | |
497 | cnt, cmd->SCp.ptr, cmd->SCp.this_residual); | |
498 | #endif | |
499 | } | |
500 | ||
501 | /* | |
502 | * Function : void initialize_SCp(Scsi_Cmnd *cmd) | |
503 | * | |
504 | * Purpose : initialize the saved data pointers for cmd to point to the | |
505 | * start of the buffer. | |
506 | * | |
507 | * Inputs : cmd - Scsi_Cmnd structure to have pointers reset. | |
508 | */ | |
509 | ||
510 | static __inline__ void initialize_SCp(Scsi_Cmnd *cmd) | |
511 | { | |
512 | /* | |
513 | * Initialize the Scsi Pointer field so that all of the commands in the | |
514 | * various queues are valid. | |
515 | */ | |
516 | ||
517 | if (cmd->use_sg) { | |
518 | cmd->SCp.buffer = (struct scatterlist *) cmd->buffer; | |
519 | cmd->SCp.buffers_residual = cmd->use_sg - 1; | |
520 | cmd->SCp.ptr = (char *) SGADDR(cmd->SCp.buffer); | |
521 | cmd->SCp.this_residual = cmd->SCp.buffer->length; | |
522 | ||
523 | /* ++roman: Try to merge some scatter-buffers if they are at | |
524 | * contiguous physical addresses. | |
525 | */ | |
526 | // merge_contiguous_buffers( cmd ); | |
527 | } else { | |
528 | cmd->SCp.buffer = NULL; | |
529 | cmd->SCp.buffers_residual = 0; | |
530 | cmd->SCp.ptr = (char *) cmd->request_buffer; | |
531 | cmd->SCp.this_residual = cmd->request_bufflen; | |
532 | } | |
533 | ||
534 | } | |
535 | ||
536 | #include <linux/config.h> | |
537 | #include <linux/delay.h> | |
538 | ||
539 | #if 1 | |
540 | static struct { | |
541 | unsigned char mask; | |
542 | const char * name;} | |
543 | signals[] = {{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" }, | |
544 | { SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD, "CD" }, { SR_IO, "IO" }, | |
545 | { SR_SEL, "SEL" }, {0, NULL}}, | |
546 | basrs[] = {{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}}, | |
547 | icrs[] = {{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"}, | |
548 | {ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"}, | |
549 | {ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"}, | |
550 | {0, NULL}}, | |
551 | mrs[] = {{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"}, | |
552 | {MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR, | |
553 | "MODE PARITY INTR"}, {MR_ENABLE_EOP_INTR,"MODE EOP INTR"}, | |
554 | {MR_MONITOR_BSY, "MODE MONITOR BSY"}, | |
555 | {MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"}, | |
556 | {0, NULL}}; | |
557 | ||
558 | /* | |
559 | * Function : void NCR5380_print(struct Scsi_Host *instance) | |
560 | * | |
561 | * Purpose : print the SCSI bus signals for debugging purposes | |
562 | * | |
563 | * Input : instance - which NCR5380 | |
564 | */ | |
565 | ||
566 | static void NCR5380_print(struct Scsi_Host *instance) { | |
567 | unsigned char status, data, basr, mr, icr, i; | |
568 | unsigned long flags; | |
569 | ||
570 | local_irq_save(flags); | |
571 | data = NCR5380_read(CURRENT_SCSI_DATA_REG); | |
572 | status = NCR5380_read(STATUS_REG); | |
573 | mr = NCR5380_read(MODE_REG); | |
574 | icr = NCR5380_read(INITIATOR_COMMAND_REG); | |
575 | basr = NCR5380_read(BUS_AND_STATUS_REG); | |
576 | local_irq_restore(flags); | |
577 | printk("STATUS_REG: %02x ", status); | |
578 | for (i = 0; signals[i].mask ; ++i) | |
579 | if (status & signals[i].mask) | |
580 | printk(",%s", signals[i].name); | |
581 | printk("\nBASR: %02x ", basr); | |
582 | for (i = 0; basrs[i].mask ; ++i) | |
583 | if (basr & basrs[i].mask) | |
584 | printk(",%s", basrs[i].name); | |
585 | printk("\nICR: %02x ", icr); | |
586 | for (i = 0; icrs[i].mask; ++i) | |
587 | if (icr & icrs[i].mask) | |
588 | printk(",%s", icrs[i].name); | |
589 | printk("\nMODE: %02x ", mr); | |
590 | for (i = 0; mrs[i].mask; ++i) | |
591 | if (mr & mrs[i].mask) | |
592 | printk(",%s", mrs[i].name); | |
593 | printk("\n"); | |
594 | } | |
595 | ||
596 | static struct { | |
597 | unsigned char value; | |
598 | const char *name; | |
599 | } phases[] = { | |
600 | {PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"}, | |
601 | {PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"}, | |
602 | {PHASE_UNKNOWN, "UNKNOWN"}}; | |
603 | ||
604 | /* | |
605 | * Function : void NCR5380_print_phase(struct Scsi_Host *instance) | |
606 | * | |
607 | * Purpose : print the current SCSI phase for debugging purposes | |
608 | * | |
609 | * Input : instance - which NCR5380 | |
610 | */ | |
611 | ||
612 | static void NCR5380_print_phase(struct Scsi_Host *instance) | |
613 | { | |
614 | unsigned char status; | |
615 | int i; | |
616 | ||
617 | status = NCR5380_read(STATUS_REG); | |
618 | if (!(status & SR_REQ)) | |
619 | printk(KERN_DEBUG "scsi%d: REQ not asserted, phase unknown.\n", HOSTNO); | |
620 | else { | |
621 | for (i = 0; (phases[i].value != PHASE_UNKNOWN) && | |
622 | (phases[i].value != (status & PHASE_MASK)); ++i); | |
623 | printk(KERN_DEBUG "scsi%d: phase %s\n", HOSTNO, phases[i].name); | |
624 | } | |
625 | } | |
626 | ||
627 | #else /* !NDEBUG */ | |
628 | ||
629 | /* dummies... */ | |
630 | __inline__ void NCR5380_print(struct Scsi_Host *instance) { }; | |
631 | __inline__ void NCR5380_print_phase(struct Scsi_Host *instance) { }; | |
632 | ||
633 | #endif | |
634 | ||
635 | /* | |
636 | * ++roman: New scheme of calling NCR5380_main() | |
637 | * | |
638 | * If we're not in an interrupt, we can call our main directly, it cannot be | |
639 | * already running. Else, we queue it on a task queue, if not 'main_running' | |
640 | * tells us that a lower level is already executing it. This way, | |
641 | * 'main_running' needs not be protected in a special way. | |
642 | * | |
643 | * queue_main() is a utility function for putting our main onto the task | |
644 | * queue, if main_running is false. It should be called only from a | |
645 | * interrupt or bottom half. | |
646 | */ | |
647 | ||
648 | #include <linux/workqueue.h> | |
649 | #include <linux/interrupt.h> | |
650 | ||
651 | static volatile int main_running = 0; | |
652 | static DECLARE_WORK(NCR5380_tqueue, (void (*)(void*))NCR5380_main, NULL); | |
653 | ||
654 | static __inline__ void queue_main(void) | |
655 | { | |
656 | if (!main_running) { | |
657 | /* If in interrupt and NCR5380_main() not already running, | |
658 | queue it on the 'immediate' task queue, to be processed | |
659 | immediately after the current interrupt processing has | |
660 | finished. */ | |
661 | schedule_work(&NCR5380_tqueue); | |
662 | } | |
663 | /* else: nothing to do: the running NCR5380_main() will pick up | |
664 | any newly queued command. */ | |
665 | } | |
666 | ||
667 | ||
668 | static inline void NCR5380_all_init (void) | |
669 | { | |
670 | static int done = 0; | |
671 | if (!done) { | |
672 | INI_PRINTK("scsi : NCR5380_all_init()\n"); | |
673 | done = 1; | |
674 | } | |
675 | } | |
676 | ||
677 | ||
678 | /* | |
679 | * Function : void NCR58380_print_options (struct Scsi_Host *instance) | |
680 | * | |
681 | * Purpose : called by probe code indicating the NCR5380 driver | |
682 | * options that were selected. | |
683 | * | |
684 | * Inputs : instance, pointer to this instance. Unused. | |
685 | */ | |
686 | ||
687 | static void __init NCR5380_print_options (struct Scsi_Host *instance) | |
688 | { | |
689 | printk(" generic options" | |
690 | #ifdef AUTOSENSE | |
691 | " AUTOSENSE" | |
692 | #endif | |
693 | #ifdef REAL_DMA | |
694 | " REAL DMA" | |
695 | #endif | |
696 | #ifdef PARITY | |
697 | " PARITY" | |
698 | #endif | |
699 | #ifdef SUPPORT_TAGS | |
700 | " SCSI-2 TAGGED QUEUING" | |
701 | #endif | |
702 | ); | |
703 | printk(" generic release=%d", NCR5380_PUBLIC_RELEASE); | |
704 | } | |
705 | ||
706 | /* | |
707 | * Function : void NCR5380_print_status (struct Scsi_Host *instance) | |
708 | * | |
709 | * Purpose : print commands in the various queues, called from | |
710 | * NCR5380_abort and NCR5380_debug to aid debugging. | |
711 | * | |
712 | * Inputs : instance, pointer to this instance. | |
713 | */ | |
714 | ||
715 | static void NCR5380_print_status (struct Scsi_Host *instance) | |
716 | { | |
717 | char *pr_bfr; | |
718 | char *start; | |
719 | int len; | |
720 | ||
721 | NCR_PRINT(NDEBUG_ANY); | |
722 | NCR_PRINT_PHASE(NDEBUG_ANY); | |
723 | ||
724 | pr_bfr = (char *) __get_free_page(GFP_ATOMIC); | |
725 | if (!pr_bfr) { | |
726 | printk("NCR5380_print_status: no memory for print buffer\n"); | |
727 | return; | |
728 | } | |
729 | len = NCR5380_proc_info(instance, pr_bfr, &start, 0, PAGE_SIZE, 0); | |
730 | pr_bfr[len] = 0; | |
731 | printk("\n%s\n", pr_bfr); | |
732 | free_page((unsigned long) pr_bfr); | |
733 | } | |
734 | ||
735 | ||
736 | /******************************************/ | |
737 | /* | |
738 | * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED] | |
739 | * | |
740 | * *buffer: I/O buffer | |
741 | * **start: if inout == FALSE pointer into buffer where user read should start | |
742 | * offset: current offset | |
743 | * length: length of buffer | |
744 | * hostno: Scsi_Host host_no | |
745 | * inout: TRUE - user is writing; FALSE - user is reading | |
746 | * | |
747 | * Return the number of bytes read from or written | |
748 | */ | |
749 | ||
750 | #undef SPRINTF | |
751 | #define SPRINTF(fmt,args...) \ | |
752 | do { if (pos + strlen(fmt) + 20 /* slop */ < buffer + length) \ | |
753 | pos += sprintf(pos, fmt , ## args); } while(0) | |
754 | static | |
755 | char *lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length); | |
756 | ||
757 | static int NCR5380_proc_info (struct Scsi_Host *instance, char *buffer, char **start, | |
758 | off_t offset, int length, int inout) | |
759 | { | |
760 | char *pos = buffer; | |
761 | struct NCR5380_hostdata *hostdata; | |
762 | Scsi_Cmnd *ptr; | |
763 | unsigned long flags; | |
764 | off_t begin = 0; | |
765 | #define check_offset() \ | |
766 | do { \ | |
767 | if (pos - buffer < offset - begin) { \ | |
768 | begin += pos - buffer; \ | |
769 | pos = buffer; \ | |
770 | } \ | |
771 | } while (0) | |
772 | ||
773 | hostdata = (struct NCR5380_hostdata *)instance->hostdata; | |
774 | ||
775 | if (inout) { /* Has data been written to the file ? */ | |
776 | return(-ENOSYS); /* Currently this is a no-op */ | |
777 | } | |
778 | SPRINTF("NCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE); | |
779 | check_offset(); | |
780 | local_irq_save(flags); | |
781 | SPRINTF("NCR5380: coroutine is%s running.\n", main_running ? "" : "n't"); | |
782 | check_offset(); | |
783 | if (!hostdata->connected) | |
784 | SPRINTF("scsi%d: no currently connected command\n", HOSTNO); | |
785 | else | |
786 | pos = lprint_Scsi_Cmnd ((Scsi_Cmnd *) hostdata->connected, | |
787 | pos, buffer, length); | |
788 | SPRINTF("scsi%d: issue_queue\n", HOSTNO); | |
789 | check_offset(); | |
790 | for (ptr = (Scsi_Cmnd *) hostdata->issue_queue; ptr; ptr = NEXT(ptr)) { | |
791 | pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length); | |
792 | check_offset(); | |
793 | } | |
794 | ||
795 | SPRINTF("scsi%d: disconnected_queue\n", HOSTNO); | |
796 | check_offset(); | |
797 | for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr; | |
798 | ptr = NEXT(ptr)) { | |
799 | pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length); | |
800 | check_offset(); | |
801 | } | |
802 | ||
803 | local_irq_restore(flags); | |
804 | *start = buffer + (offset - begin); | |
805 | if (pos - buffer < offset - begin) | |
806 | return 0; | |
807 | else if (pos - buffer - (offset - begin) < length) | |
808 | return pos - buffer - (offset - begin); | |
809 | return length; | |
810 | } | |
811 | ||
812 | static char * | |
813 | lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length) | |
814 | { | |
815 | int i, s; | |
816 | unsigned char *command; | |
817 | SPRINTF("scsi%d: destination target %d, lun %d\n", | |
818 | H_NO(cmd), cmd->device->id, cmd->device->lun); | |
819 | SPRINTF(" command = "); | |
820 | command = cmd->cmnd; | |
821 | SPRINTF("%2d (0x%02x)", command[0], command[0]); | |
822 | for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i) | |
823 | SPRINTF(" %02x", command[i]); | |
824 | SPRINTF("\n"); | |
825 | return pos; | |
826 | } | |
827 | ||
828 | ||
829 | /* | |
830 | * Function : void NCR5380_init (struct Scsi_Host *instance) | |
831 | * | |
832 | * Purpose : initializes *instance and corresponding 5380 chip. | |
833 | * | |
834 | * Inputs : instance - instantiation of the 5380 driver. | |
835 | * | |
836 | * Notes : I assume that the host, hostno, and id bits have been | |
837 | * set correctly. I don't care about the irq and other fields. | |
838 | * | |
839 | */ | |
840 | ||
841 | static int NCR5380_init (struct Scsi_Host *instance, int flags) | |
842 | { | |
843 | int i; | |
844 | SETUP_HOSTDATA(instance); | |
845 | ||
846 | NCR5380_all_init(); | |
847 | ||
848 | hostdata->aborted = 0; | |
849 | hostdata->id_mask = 1 << instance->this_id; | |
850 | hostdata->id_higher_mask = 0; | |
851 | for (i = hostdata->id_mask; i <= 0x80; i <<= 1) | |
852 | if (i > hostdata->id_mask) | |
853 | hostdata->id_higher_mask |= i; | |
854 | for (i = 0; i < 8; ++i) | |
855 | hostdata->busy[i] = 0; | |
856 | #ifdef SUPPORT_TAGS | |
857 | init_tags(); | |
858 | #endif | |
859 | #if defined (REAL_DMA) | |
860 | hostdata->dma_len = 0; | |
861 | #endif | |
862 | hostdata->targets_present = 0; | |
863 | hostdata->connected = NULL; | |
864 | hostdata->issue_queue = NULL; | |
865 | hostdata->disconnected_queue = NULL; | |
866 | hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT; | |
867 | ||
868 | if (!the_template) { | |
869 | the_template = instance->hostt; | |
870 | first_instance = instance; | |
871 | } | |
872 | ||
873 | ||
874 | #ifndef AUTOSENSE | |
875 | if ((instance->cmd_per_lun > 1) || (instance->can_queue > 1)) | |
876 | printk("scsi%d: WARNING : support for multiple outstanding commands enabled\n" | |
877 | " without AUTOSENSE option, contingent allegiance conditions may\n" | |
878 | " be incorrectly cleared.\n", HOSTNO); | |
879 | #endif /* def AUTOSENSE */ | |
880 | ||
881 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
882 | NCR5380_write(MODE_REG, MR_BASE); | |
883 | NCR5380_write(TARGET_COMMAND_REG, 0); | |
884 | NCR5380_write(SELECT_ENABLE_REG, 0); | |
885 | ||
886 | return 0; | |
887 | } | |
888 | ||
889 | /* | |
890 | * Function : int NCR5380_queue_command (Scsi_Cmnd *cmd, | |
891 | * void (*done)(Scsi_Cmnd *)) | |
892 | * | |
893 | * Purpose : enqueues a SCSI command | |
894 | * | |
895 | * Inputs : cmd - SCSI command, done - function called on completion, with | |
896 | * a pointer to the command descriptor. | |
897 | * | |
898 | * Returns : 0 | |
899 | * | |
900 | * Side effects : | |
901 | * cmd is added to the per instance issue_queue, with minor | |
902 | * twiddling done to the host specific fields of cmd. If the | |
903 | * main coroutine is not running, it is restarted. | |
904 | * | |
905 | */ | |
906 | ||
907 | /* Only make static if a wrapper function is used */ | |
908 | static int NCR5380_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *)) | |
909 | { | |
910 | SETUP_HOSTDATA(cmd->device->host); | |
911 | Scsi_Cmnd *tmp; | |
912 | unsigned long flags; | |
913 | ||
914 | #if (NDEBUG & NDEBUG_NO_WRITE) | |
915 | switch (cmd->cmnd[0]) { | |
916 | case WRITE_6: | |
917 | case WRITE_10: | |
918 | printk(KERN_NOTICE "scsi%d: WRITE attempted with NO_WRITE debugging flag set\n", | |
919 | H_NO(cmd)); | |
920 | cmd->result = (DID_ERROR << 16); | |
921 | done(cmd); | |
922 | return 0; | |
923 | } | |
924 | #endif /* (NDEBUG & NDEBUG_NO_WRITE) */ | |
925 | ||
926 | ||
927 | #ifdef NCR5380_STATS | |
928 | # if 0 | |
929 | if (!hostdata->connected && !hostdata->issue_queue && | |
930 | !hostdata->disconnected_queue) { | |
931 | hostdata->timebase = jiffies; | |
932 | } | |
933 | # endif | |
934 | # ifdef NCR5380_STAT_LIMIT | |
935 | if (cmd->request_bufflen > NCR5380_STAT_LIMIT) | |
936 | # endif | |
937 | switch (cmd->cmnd[0]) | |
938 | { | |
939 | case WRITE: | |
940 | case WRITE_6: | |
941 | case WRITE_10: | |
942 | hostdata->time_write[cmd->device->id] -= (jiffies - hostdata->timebase); | |
943 | hostdata->bytes_write[cmd->device->id] += cmd->request_bufflen; | |
944 | hostdata->pendingw++; | |
945 | break; | |
946 | case READ: | |
947 | case READ_6: | |
948 | case READ_10: | |
949 | hostdata->time_read[cmd->device->id] -= (jiffies - hostdata->timebase); | |
950 | hostdata->bytes_read[cmd->device->id] += cmd->request_bufflen; | |
951 | hostdata->pendingr++; | |
952 | break; | |
953 | } | |
954 | #endif | |
955 | ||
956 | /* | |
957 | * We use the host_scribble field as a pointer to the next command | |
958 | * in a queue | |
959 | */ | |
960 | ||
961 | NEXT(cmd) = NULL; | |
962 | cmd->scsi_done = done; | |
963 | ||
964 | cmd->result = 0; | |
965 | ||
966 | ||
967 | /* | |
968 | * Insert the cmd into the issue queue. Note that REQUEST SENSE | |
969 | * commands are added to the head of the queue since any command will | |
970 | * clear the contingent allegiance condition that exists and the | |
971 | * sense data is only guaranteed to be valid while the condition exists. | |
972 | */ | |
973 | ||
974 | local_irq_save(flags); | |
975 | /* ++guenther: now that the issue queue is being set up, we can lock ST-DMA. | |
976 | * Otherwise a running NCR5380_main may steal the lock. | |
977 | * Lock before actually inserting due to fairness reasons explained in | |
978 | * atari_scsi.c. If we insert first, then it's impossible for this driver | |
979 | * to release the lock. | |
980 | * Stop timer for this command while waiting for the lock, or timeouts | |
981 | * may happen (and they really do), and it's no good if the command doesn't | |
982 | * appear in any of the queues. | |
983 | * ++roman: Just disabling the NCR interrupt isn't sufficient here, | |
984 | * because also a timer int can trigger an abort or reset, which would | |
985 | * alter queues and touch the lock. | |
986 | */ | |
987 | if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) { | |
988 | LIST(cmd, hostdata->issue_queue); | |
989 | NEXT(cmd) = hostdata->issue_queue; | |
990 | hostdata->issue_queue = cmd; | |
991 | } else { | |
992 | for (tmp = (Scsi_Cmnd *)hostdata->issue_queue; | |
993 | NEXT(tmp); tmp = NEXT(tmp)) | |
994 | ; | |
995 | LIST(cmd, tmp); | |
996 | NEXT(tmp) = cmd; | |
997 | } | |
998 | ||
999 | local_irq_restore(flags); | |
1000 | ||
1001 | QU_PRINTK("scsi%d: command added to %s of queue\n", H_NO(cmd), | |
1002 | (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail"); | |
1003 | ||
1004 | /* If queue_command() is called from an interrupt (real one or bottom | |
1005 | * half), we let queue_main() do the job of taking care about main. If it | |
1006 | * is already running, this is a no-op, else main will be queued. | |
1007 | * | |
1008 | * If we're not in an interrupt, we can call NCR5380_main() | |
1009 | * unconditionally, because it cannot be already running. | |
1010 | */ | |
1011 | if (in_interrupt() || ((flags >> 8) & 7) >= 6) | |
1012 | queue_main(); | |
1013 | else | |
1014 | NCR5380_main(NULL); | |
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | /* | |
1019 | * Function : NCR5380_main (void) | |
1020 | * | |
1021 | * Purpose : NCR5380_main is a coroutine that runs as long as more work can | |
1022 | * be done on the NCR5380 host adapters in a system. Both | |
1023 | * NCR5380_queue_command() and NCR5380_intr() will try to start it | |
1024 | * in case it is not running. | |
1025 | * | |
1026 | * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should | |
1027 | * reenable them. This prevents reentrancy and kernel stack overflow. | |
1028 | */ | |
1029 | ||
1030 | static void NCR5380_main (void *bl) | |
1031 | { | |
1032 | Scsi_Cmnd *tmp, *prev; | |
1033 | struct Scsi_Host *instance = first_instance; | |
1034 | struct NCR5380_hostdata *hostdata = HOSTDATA(instance); | |
1035 | int done; | |
1036 | unsigned long flags; | |
1037 | ||
1038 | /* | |
1039 | * We run (with interrupts disabled) until we're sure that none of | |
1040 | * the host adapters have anything that can be done, at which point | |
1041 | * we set main_running to 0 and exit. | |
1042 | * | |
1043 | * Interrupts are enabled before doing various other internal | |
1044 | * instructions, after we've decided that we need to run through | |
1045 | * the loop again. | |
1046 | * | |
1047 | * this should prevent any race conditions. | |
1048 | * | |
1049 | * ++roman: Just disabling the NCR interrupt isn't sufficient here, | |
1050 | * because also a timer int can trigger an abort or reset, which can | |
1051 | * alter queues and touch the Falcon lock. | |
1052 | */ | |
1053 | ||
1054 | /* Tell int handlers main() is now already executing. Note that | |
1055 | no races are possible here. If an int comes in before | |
1056 | 'main_running' is set here, and queues/executes main via the | |
1057 | task queue, it doesn't do any harm, just this instance of main | |
1058 | won't find any work left to do. */ | |
1059 | if (main_running) | |
1060 | return; | |
1061 | main_running = 1; | |
1062 | ||
1063 | local_save_flags(flags); | |
1064 | do { | |
1065 | local_irq_disable(); /* Freeze request queues */ | |
1066 | done = 1; | |
1067 | ||
1068 | if (!hostdata->connected) { | |
1069 | MAIN_PRINTK( "scsi%d: not connected\n", HOSTNO ); | |
1070 | /* | |
1071 | * Search through the issue_queue for a command destined | |
1072 | * for a target that's not busy. | |
1073 | */ | |
1074 | #if (NDEBUG & NDEBUG_LISTS) | |
1075 | for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, prev = NULL; | |
1076 | tmp && (tmp != prev); prev = tmp, tmp = NEXT(tmp)) | |
1077 | ; | |
1078 | if ((tmp == prev) && tmp) printk(" LOOP\n");/* else printk("\n");*/ | |
1079 | #endif | |
1080 | for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, | |
1081 | prev = NULL; tmp; prev = tmp, tmp = NEXT(tmp) ) { | |
1082 | ||
1083 | #if (NDEBUG & NDEBUG_LISTS) | |
1084 | if (prev != tmp) | |
1085 | printk("MAIN tmp=%p target=%d busy=%d lun=%d\n", | |
1086 | tmp, tmp->target, hostdata->busy[tmp->target], | |
1087 | tmp->lun); | |
1088 | #endif | |
1089 | /* When we find one, remove it from the issue queue. */ | |
1090 | /* ++guenther: possible race with Falcon locking */ | |
1091 | if ( | |
1092 | #ifdef SUPPORT_TAGS | |
1093 | !is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE) | |
1094 | #else | |
1095 | !(hostdata->busy[tmp->device->id] & (1 << tmp->device->lun)) | |
1096 | #endif | |
1097 | ) { | |
1098 | /* ++guenther: just to be sure, this must be atomic */ | |
1099 | local_irq_disable(); | |
1100 | if (prev) { | |
1101 | REMOVE(prev, NEXT(prev), tmp, NEXT(tmp)); | |
1102 | NEXT(prev) = NEXT(tmp); | |
1103 | } else { | |
1104 | REMOVE(-1, hostdata->issue_queue, tmp, NEXT(tmp)); | |
1105 | hostdata->issue_queue = NEXT(tmp); | |
1106 | } | |
1107 | NEXT(tmp) = NULL; | |
1108 | ||
1109 | /* reenable interrupts after finding one */ | |
1110 | local_irq_restore(flags); | |
1111 | ||
1112 | /* | |
1113 | * Attempt to establish an I_T_L nexus here. | |
1114 | * On success, instance->hostdata->connected is set. | |
1115 | * On failure, we must add the command back to the | |
1116 | * issue queue so we can keep trying. | |
1117 | */ | |
1118 | MAIN_PRINTK("scsi%d: main(): command for target %d " | |
1119 | "lun %d removed from issue_queue\n", | |
1120 | HOSTNO, tmp->target, tmp->lun); | |
1121 | /* | |
1122 | * REQUEST SENSE commands are issued without tagged | |
1123 | * queueing, even on SCSI-II devices because the | |
1124 | * contingent allegiance condition exists for the | |
1125 | * entire unit. | |
1126 | */ | |
1127 | /* ++roman: ...and the standard also requires that | |
1128 | * REQUEST SENSE command are untagged. | |
1129 | */ | |
1130 | ||
1131 | #ifdef SUPPORT_TAGS | |
1132 | cmd_get_tag( tmp, tmp->cmnd[0] != REQUEST_SENSE ); | |
1133 | #endif | |
1134 | if (!NCR5380_select(instance, tmp, | |
1135 | (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE : | |
1136 | TAG_NEXT)) { | |
1137 | break; | |
1138 | } else { | |
1139 | local_irq_disable(); | |
1140 | LIST(tmp, hostdata->issue_queue); | |
1141 | NEXT(tmp) = hostdata->issue_queue; | |
1142 | hostdata->issue_queue = tmp; | |
1143 | #ifdef SUPPORT_TAGS | |
1144 | cmd_free_tag( tmp ); | |
1145 | #endif | |
1146 | local_irq_restore(flags); | |
1147 | MAIN_PRINTK("scsi%d: main(): select() failed, " | |
1148 | "returned to issue_queue\n", HOSTNO); | |
1149 | if (hostdata->connected) | |
1150 | break; | |
1151 | } | |
1152 | } /* if target/lun/target queue is not busy */ | |
1153 | } /* for issue_queue */ | |
1154 | } /* if (!hostdata->connected) */ | |
1155 | if (hostdata->connected | |
1156 | #ifdef REAL_DMA | |
1157 | && !hostdata->dma_len | |
1158 | #endif | |
1159 | ) { | |
1160 | local_irq_restore(flags); | |
1161 | MAIN_PRINTK("scsi%d: main: performing information transfer\n", | |
1162 | HOSTNO); | |
1163 | NCR5380_information_transfer(instance); | |
1164 | MAIN_PRINTK("scsi%d: main: done set false\n", HOSTNO); | |
1165 | done = 0; | |
1166 | } | |
1167 | } while (!done); | |
1168 | ||
1169 | /* Better allow ints _after_ 'main_running' has been cleared, else | |
1170 | an interrupt could believe we'll pick up the work it left for | |
1171 | us, but we won't see it anymore here... */ | |
1172 | main_running = 0; | |
1173 | local_irq_restore(flags); | |
1174 | } | |
1175 | ||
1176 | ||
1177 | #ifdef REAL_DMA | |
1178 | /* | |
1179 | * Function : void NCR5380_dma_complete (struct Scsi_Host *instance) | |
1180 | * | |
1181 | * Purpose : Called by interrupt handler when DMA finishes or a phase | |
1182 | * mismatch occurs (which would finish the DMA transfer). | |
1183 | * | |
1184 | * Inputs : instance - this instance of the NCR5380. | |
1185 | * | |
1186 | */ | |
1187 | ||
1188 | static void NCR5380_dma_complete( struct Scsi_Host *instance ) | |
1189 | { | |
1190 | SETUP_HOSTDATA(instance); | |
1191 | int transfered; | |
1192 | unsigned char **data; | |
1193 | volatile int *count; | |
1194 | ||
1195 | if (!hostdata->connected) { | |
1196 | printk(KERN_WARNING "scsi%d: received end of DMA interrupt with " | |
1197 | "no connected cmd\n", HOSTNO); | |
1198 | return; | |
1199 | } | |
1200 | ||
1201 | DMA_PRINTK("scsi%d: real DMA transfer complete, basr 0x%X, sr 0x%X\n", | |
1202 | HOSTNO, NCR5380_read(BUS_AND_STATUS_REG), | |
1203 | NCR5380_read(STATUS_REG)); | |
1204 | ||
1205 | if((sun3scsi_dma_finish(rq_data_dir(hostdata->connected->request)))) { | |
1206 | printk("scsi%d: overrun in UDC counter -- not prepared to deal with this!\n", HOSTNO); | |
1207 | printk("please e-mail sammy@sammy.net with a description of how this\n"); | |
1208 | printk("error was produced.\n"); | |
1209 | BUG(); | |
1210 | } | |
1211 | ||
1212 | /* make sure we're not stuck in a data phase */ | |
1213 | if((NCR5380_read(BUS_AND_STATUS_REG) & (BASR_PHASE_MATCH | | |
1214 | BASR_ACK)) == | |
1215 | (BASR_PHASE_MATCH | BASR_ACK)) { | |
1216 | printk("scsi%d: BASR %02x\n", HOSTNO, NCR5380_read(BUS_AND_STATUS_REG)); | |
1217 | printk("scsi%d: bus stuck in data phase -- probably a single byte " | |
1218 | "overrun!\n", HOSTNO); | |
1219 | printk("not prepared for this error!\n"); | |
1220 | printk("please e-mail sammy@sammy.net with a description of how this\n"); | |
1221 | printk("error was produced.\n"); | |
1222 | BUG(); | |
1223 | } | |
1224 | ||
1225 | ||
1226 | ||
1227 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1228 | NCR5380_write(MODE_REG, MR_BASE); | |
1229 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1230 | ||
1231 | transfered = hostdata->dma_len - NCR5380_dma_residual(instance); | |
1232 | hostdata->dma_len = 0; | |
1233 | ||
1234 | data = (unsigned char **) &(hostdata->connected->SCp.ptr); | |
1235 | count = &(hostdata->connected->SCp.this_residual); | |
1236 | *data += transfered; | |
1237 | *count -= transfered; | |
1238 | ||
1239 | } | |
1240 | #endif /* REAL_DMA */ | |
1241 | ||
1242 | ||
1243 | /* | |
1244 | * Function : void NCR5380_intr (int irq) | |
1245 | * | |
1246 | * Purpose : handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses | |
1247 | * from the disconnected queue, and restarting NCR5380_main() | |
1248 | * as required. | |
1249 | * | |
1250 | * Inputs : int irq, irq that caused this interrupt. | |
1251 | * | |
1252 | */ | |
1253 | ||
1254 | static irqreturn_t NCR5380_intr (int irq, void *dev_id, struct pt_regs *regs) | |
1255 | { | |
1256 | struct Scsi_Host *instance = first_instance; | |
1257 | int done = 1, handled = 0; | |
1258 | unsigned char basr; | |
1259 | ||
1260 | INT_PRINTK("scsi%d: NCR5380 irq triggered\n", HOSTNO); | |
1261 | ||
1262 | /* Look for pending interrupts */ | |
1263 | basr = NCR5380_read(BUS_AND_STATUS_REG); | |
1264 | INT_PRINTK("scsi%d: BASR=%02x\n", HOSTNO, basr); | |
1265 | /* dispatch to appropriate routine if found and done=0 */ | |
1266 | if (basr & BASR_IRQ) { | |
1267 | NCR_PRINT(NDEBUG_INTR); | |
1268 | if ((NCR5380_read(STATUS_REG) & (SR_SEL|SR_IO)) == (SR_SEL|SR_IO)) { | |
1269 | done = 0; | |
1270 | ENABLE_IRQ(); | |
1271 | INT_PRINTK("scsi%d: SEL interrupt\n", HOSTNO); | |
1272 | NCR5380_reselect(instance); | |
1273 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1274 | } | |
1275 | else if (basr & BASR_PARITY_ERROR) { | |
1276 | INT_PRINTK("scsi%d: PARITY interrupt\n", HOSTNO); | |
1277 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1278 | } | |
1279 | else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) { | |
1280 | INT_PRINTK("scsi%d: RESET interrupt\n", HOSTNO); | |
1281 | (void)NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1282 | } | |
1283 | else { | |
1284 | /* | |
1285 | * The rest of the interrupt conditions can occur only during a | |
1286 | * DMA transfer | |
1287 | */ | |
1288 | ||
1289 | #if defined(REAL_DMA) | |
1290 | /* | |
1291 | * We should only get PHASE MISMATCH and EOP interrupts if we have | |
1292 | * DMA enabled, so do a sanity check based on the current setting | |
1293 | * of the MODE register. | |
1294 | */ | |
1295 | ||
1296 | if ((NCR5380_read(MODE_REG) & MR_DMA_MODE) && | |
1297 | ((basr & BASR_END_DMA_TRANSFER) || | |
1298 | !(basr & BASR_PHASE_MATCH))) { | |
1299 | ||
1300 | INT_PRINTK("scsi%d: PHASE MISM or EOP interrupt\n", HOSTNO); | |
1301 | NCR5380_dma_complete( instance ); | |
1302 | done = 0; | |
1303 | ENABLE_IRQ(); | |
1304 | } else | |
1305 | #endif /* REAL_DMA */ | |
1306 | { | |
1307 | /* MS: Ignore unknown phase mismatch interrupts (caused by EOP interrupt) */ | |
1308 | if (basr & BASR_PHASE_MATCH) | |
1309 | INT_PRINTK("scsi%d: unknown interrupt, " | |
1310 | "BASR 0x%x, MR 0x%x, SR 0x%x\n", | |
1311 | HOSTNO, basr, NCR5380_read(MODE_REG), | |
1312 | NCR5380_read(STATUS_REG)); | |
1313 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1314 | #ifdef SUN3_SCSI_VME | |
1315 | dregs->csr |= CSR_DMA_ENABLE; | |
1316 | #endif | |
1317 | } | |
1318 | } /* if !(SELECTION || PARITY) */ | |
1319 | handled = 1; | |
1320 | } /* BASR & IRQ */ | |
1321 | else { | |
1322 | ||
1323 | printk(KERN_NOTICE "scsi%d: interrupt without IRQ bit set in BASR, " | |
1324 | "BASR 0x%X, MR 0x%X, SR 0x%x\n", HOSTNO, basr, | |
1325 | NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG)); | |
1326 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1327 | #ifdef SUN3_SCSI_VME | |
1328 | dregs->csr |= CSR_DMA_ENABLE; | |
1329 | #endif | |
1330 | } | |
1331 | ||
1332 | if (!done) { | |
1333 | INT_PRINTK("scsi%d: in int routine, calling main\n", HOSTNO); | |
1334 | /* Put a call to NCR5380_main() on the queue... */ | |
1335 | queue_main(); | |
1336 | } | |
1337 | return IRQ_RETVAL(handled); | |
1338 | } | |
1339 | ||
1340 | #ifdef NCR5380_STATS | |
1341 | static void collect_stats(struct NCR5380_hostdata* hostdata, Scsi_Cmnd* cmd) | |
1342 | { | |
1343 | # ifdef NCR5380_STAT_LIMIT | |
1344 | if (cmd->request_bufflen > NCR5380_STAT_LIMIT) | |
1345 | # endif | |
1346 | switch (cmd->cmnd[0]) | |
1347 | { | |
1348 | case WRITE: | |
1349 | case WRITE_6: | |
1350 | case WRITE_10: | |
1351 | hostdata->time_write[cmd->device->id] += (jiffies - hostdata->timebase); | |
1352 | /*hostdata->bytes_write[cmd->device->id] += cmd->request_bufflen;*/ | |
1353 | hostdata->pendingw--; | |
1354 | break; | |
1355 | case READ: | |
1356 | case READ_6: | |
1357 | case READ_10: | |
1358 | hostdata->time_read[cmd->device->id] += (jiffies - hostdata->timebase); | |
1359 | /*hostdata->bytes_read[cmd->device->id] += cmd->request_bufflen;*/ | |
1360 | hostdata->pendingr--; | |
1361 | break; | |
1362 | } | |
1363 | } | |
1364 | #endif | |
1365 | ||
1366 | /* | |
1367 | * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, | |
1368 | * int tag); | |
1369 | * | |
1370 | * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command, | |
1371 | * including ARBITRATION, SELECTION, and initial message out for | |
1372 | * IDENTIFY and queue messages. | |
1373 | * | |
1374 | * Inputs : instance - instantiation of the 5380 driver on which this | |
1375 | * target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for | |
1376 | * new tag, TAG_NONE for untagged queueing, otherwise set to the tag for | |
1377 | * the command that is presently connected. | |
1378 | * | |
1379 | * Returns : -1 if selection could not execute for some reason, | |
1380 | * 0 if selection succeeded or failed because the target | |
1381 | * did not respond. | |
1382 | * | |
1383 | * Side effects : | |
1384 | * If bus busy, arbitration failed, etc, NCR5380_select() will exit | |
1385 | * with registers as they should have been on entry - ie | |
1386 | * SELECT_ENABLE will be set appropriately, the NCR5380 | |
1387 | * will cease to drive any SCSI bus signals. | |
1388 | * | |
1389 | * If successful : I_T_L or I_T_L_Q nexus will be established, | |
1390 | * instance->connected will be set to cmd. | |
1391 | * SELECT interrupt will be disabled. | |
1392 | * | |
1393 | * If failed (no target) : cmd->scsi_done() will be called, and the | |
1394 | * cmd->result host byte set to DID_BAD_TARGET. | |
1395 | */ | |
1396 | ||
1397 | static int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag) | |
1398 | { | |
1399 | SETUP_HOSTDATA(instance); | |
1400 | unsigned char tmp[3], phase; | |
1401 | unsigned char *data; | |
1402 | int len; | |
1403 | unsigned long timeout; | |
1404 | unsigned long flags; | |
1405 | ||
1406 | hostdata->restart_select = 0; | |
1407 | NCR_PRINT(NDEBUG_ARBITRATION); | |
1408 | ARB_PRINTK("scsi%d: starting arbitration, id = %d\n", HOSTNO, | |
1409 | instance->this_id); | |
1410 | ||
1411 | /* | |
1412 | * Set the phase bits to 0, otherwise the NCR5380 won't drive the | |
1413 | * data bus during SELECTION. | |
1414 | */ | |
1415 | ||
1416 | local_irq_save(flags); | |
1417 | if (hostdata->connected) { | |
1418 | local_irq_restore(flags); | |
1419 | return -1; | |
1420 | } | |
1421 | NCR5380_write(TARGET_COMMAND_REG, 0); | |
1422 | ||
1423 | ||
1424 | /* | |
1425 | * Start arbitration. | |
1426 | */ | |
1427 | ||
1428 | NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask); | |
1429 | NCR5380_write(MODE_REG, MR_ARBITRATE); | |
1430 | ||
1431 | local_irq_restore(flags); | |
1432 | ||
1433 | /* Wait for arbitration logic to complete */ | |
1434 | #if NCR_TIMEOUT | |
1435 | { | |
1436 | unsigned long timeout = jiffies + 2*NCR_TIMEOUT; | |
1437 | ||
1438 | while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) | |
1439 | && time_before(jiffies, timeout) && !hostdata->connected) | |
1440 | ; | |
1441 | if (time_after_eq(jiffies, timeout)) | |
1442 | { | |
1443 | printk("scsi : arbitration timeout at %d\n", __LINE__); | |
1444 | NCR5380_write(MODE_REG, MR_BASE); | |
1445 | NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask); | |
1446 | return -1; | |
1447 | } | |
1448 | } | |
1449 | #else /* NCR_TIMEOUT */ | |
1450 | while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) | |
1451 | && !hostdata->connected); | |
1452 | #endif | |
1453 | ||
1454 | ARB_PRINTK("scsi%d: arbitration complete\n", HOSTNO); | |
1455 | ||
1456 | if (hostdata->connected) { | |
1457 | NCR5380_write(MODE_REG, MR_BASE); | |
1458 | return -1; | |
1459 | } | |
1460 | /* | |
1461 | * The arbitration delay is 2.2us, but this is a minimum and there is | |
1462 | * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate | |
1463 | * the integral nature of udelay(). | |
1464 | * | |
1465 | */ | |
1466 | ||
1467 | udelay(3); | |
1468 | ||
1469 | /* Check for lost arbitration */ | |
1470 | if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1471 | (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) || | |
1472 | (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1473 | hostdata->connected) { | |
1474 | NCR5380_write(MODE_REG, MR_BASE); | |
1475 | ARB_PRINTK("scsi%d: lost arbitration, deasserting MR_ARBITRATE\n", | |
1476 | HOSTNO); | |
1477 | return -1; | |
1478 | } | |
1479 | ||
1480 | /* after/during arbitration, BSY should be asserted. | |
1481 | IBM DPES-31080 Version S31Q works now */ | |
1482 | /* Tnx to Thomas_Roesch@m2.maus.de for finding this! (Roman) */ | |
1483 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_SEL | | |
1484 | ICR_ASSERT_BSY ) ; | |
1485 | ||
1486 | if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1487 | hostdata->connected) { | |
1488 | NCR5380_write(MODE_REG, MR_BASE); | |
1489 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1490 | ARB_PRINTK("scsi%d: lost arbitration, deasserting ICR_ASSERT_SEL\n", | |
1491 | HOSTNO); | |
1492 | return -1; | |
1493 | } | |
1494 | ||
1495 | /* | |
1496 | * Again, bus clear + bus settle time is 1.2us, however, this is | |
1497 | * a minimum so we'll udelay ceil(1.2) | |
1498 | */ | |
1499 | ||
1500 | #ifdef CONFIG_ATARI_SCSI_TOSHIBA_DELAY | |
1501 | /* ++roman: But some targets (see above :-) seem to need a bit more... */ | |
1502 | udelay(15); | |
1503 | #else | |
1504 | udelay(2); | |
1505 | #endif | |
1506 | ||
1507 | if (hostdata->connected) { | |
1508 | NCR5380_write(MODE_REG, MR_BASE); | |
1509 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1510 | return -1; | |
1511 | } | |
1512 | ||
1513 | ARB_PRINTK("scsi%d: won arbitration\n", HOSTNO); | |
1514 | ||
1515 | /* | |
1516 | * Now that we have won arbitration, start Selection process, asserting | |
1517 | * the host and target ID's on the SCSI bus. | |
1518 | */ | |
1519 | ||
1520 | NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << cmd->device->id))); | |
1521 | ||
1522 | /* | |
1523 | * Raise ATN while SEL is true before BSY goes false from arbitration, | |
1524 | * since this is the only way to guarantee that we'll get a MESSAGE OUT | |
1525 | * phase immediately after selection. | |
1526 | */ | |
1527 | ||
1528 | NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_BSY | | |
1529 | ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL )); | |
1530 | NCR5380_write(MODE_REG, MR_BASE); | |
1531 | ||
1532 | /* | |
1533 | * Reselect interrupts must be turned off prior to the dropping of BSY, | |
1534 | * otherwise we will trigger an interrupt. | |
1535 | */ | |
1536 | ||
1537 | if (hostdata->connected) { | |
1538 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1539 | return -1; | |
1540 | } | |
1541 | ||
1542 | NCR5380_write(SELECT_ENABLE_REG, 0); | |
1543 | ||
1544 | /* | |
1545 | * The initiator shall then wait at least two deskew delays and release | |
1546 | * the BSY signal. | |
1547 | */ | |
1548 | udelay(1); /* wingel -- wait two bus deskew delay >2*45ns */ | |
1549 | ||
1550 | /* Reset BSY */ | |
1551 | NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_DATA | | |
1552 | ICR_ASSERT_ATN | ICR_ASSERT_SEL)); | |
1553 | ||
1554 | /* | |
1555 | * Something weird happens when we cease to drive BSY - looks | |
1556 | * like the board/chip is letting us do another read before the | |
1557 | * appropriate propagation delay has expired, and we're confusing | |
1558 | * a BSY signal from ourselves as the target's response to SELECTION. | |
1559 | * | |
1560 | * A small delay (the 'C++' frontend breaks the pipeline with an | |
1561 | * unnecessary jump, making it work on my 386-33/Trantor T128, the | |
1562 | * tighter 'C' code breaks and requires this) solves the problem - | |
1563 | * the 1 us delay is arbitrary, and only used because this delay will | |
1564 | * be the same on other platforms and since it works here, it should | |
1565 | * work there. | |
1566 | * | |
1567 | * wingel suggests that this could be due to failing to wait | |
1568 | * one deskew delay. | |
1569 | */ | |
1570 | ||
1571 | udelay(1); | |
1572 | ||
1573 | SEL_PRINTK("scsi%d: selecting target %d\n", HOSTNO, cmd->device->id); | |
1574 | ||
1575 | /* | |
1576 | * The SCSI specification calls for a 250 ms timeout for the actual | |
1577 | * selection. | |
1578 | */ | |
1579 | ||
1580 | timeout = jiffies + 25; | |
1581 | ||
1582 | /* | |
1583 | * XXX very interesting - we're seeing a bounce where the BSY we | |
1584 | * asserted is being reflected / still asserted (propagation delay?) | |
1585 | * and it's detecting as true. Sigh. | |
1586 | */ | |
1587 | ||
1588 | #if 0 | |
1589 | /* ++roman: If a target conformed to the SCSI standard, it wouldn't assert | |
1590 | * IO while SEL is true. But again, there are some disks out the in the | |
1591 | * world that do that nevertheless. (Somebody claimed that this announces | |
1592 | * reselection capability of the target.) So we better skip that test and | |
1593 |