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1da177e4 LT |
1 | /* |
2 | * NCR 5380 generic driver routines. These should make it *trivial* | |
3 | * to implement 5380 SCSI drivers under Linux with a non-trantor | |
4 | * architecture. | |
5 | * | |
6 | * Note that these routines also work with NR53c400 family chips. | |
7 | * | |
8 | * Copyright 1993, Drew Eckhardt | |
9 | * Visionary Computing | |
10 | * (Unix and Linux consulting and custom programming) | |
11 | * drew@colorado.edu | |
12 | * +1 (303) 666-5836 | |
13 | * | |
14 | * DISTRIBUTION RELEASE 6. | |
15 | * | |
16 | * For more information, please consult | |
17 | * | |
18 | * NCR 5380 Family | |
19 | * SCSI Protocol Controller | |
20 | * Databook | |
21 | * | |
22 | * NCR Microelectronics | |
23 | * 1635 Aeroplaza Drive | |
24 | * Colorado Springs, CO 80916 | |
25 | * 1+ (719) 578-3400 | |
26 | * 1+ (800) 334-5454 | |
27 | */ | |
28 | ||
29 | /* | |
30 | * ++roman: To port the 5380 driver to the Atari, I had to do some changes in | |
31 | * this file, too: | |
32 | * | |
33 | * - Some of the debug statements were incorrect (undefined variables and the | |
34 | * like). I fixed that. | |
35 | * | |
36 | * - In information_transfer(), I think a #ifdef was wrong. Looking at the | |
37 | * possible DMA transfer size should also happen for REAL_DMA. I added this | |
38 | * in the #if statement. | |
39 | * | |
40 | * - When using real DMA, information_transfer() should return in a DATAOUT | |
41 | * phase after starting the DMA. It has nothing more to do. | |
42 | * | |
43 | * - The interrupt service routine should run main after end of DMA, too (not | |
44 | * only after RESELECTION interrupts). Additionally, it should _not_ test | |
45 | * for more interrupts after running main, since a DMA process may have | |
46 | * been started and interrupts are turned on now. The new int could happen | |
47 | * inside the execution of NCR5380_intr(), leading to recursive | |
48 | * calls. | |
49 | * | |
50 | * - I've added a function merge_contiguous_buffers() that tries to | |
51 | * merge scatter-gather buffers that are located at contiguous | |
52 | * physical addresses and can be processed with the same DMA setup. | |
53 | * Since most scatter-gather operations work on a page (4K) of | |
54 | * 4 buffers (1K), in more than 90% of all cases three interrupts and | |
55 | * DMA setup actions are saved. | |
56 | * | |
57 | * - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA | |
58 | * and USLEEP, because these were messing up readability and will never be | |
59 | * needed for Atari SCSI. | |
60 | * | |
61 | * - I've revised the NCR5380_main() calling scheme (relax the 'main_running' | |
62 | * stuff), and 'main' is executed in a bottom half if awoken by an | |
63 | * interrupt. | |
64 | * | |
65 | * - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..." | |
66 | * constructs. In my eyes, this made the source rather unreadable, so I | |
67 | * finally replaced that by the *_PRINTK() macros. | |
68 | * | |
69 | */ | |
70 | ||
71 | /* | |
72 | * Further development / testing that should be done : | |
73 | * 1. Test linked command handling code after Eric is ready with | |
74 | * the high level code. | |
75 | */ | |
db9dff36 | 76 | #include <scsi/scsi_dbg.h> |
1da177e4 LT |
77 | |
78 | #if (NDEBUG & NDEBUG_LISTS) | |
79 | #define LIST(x,y) \ | |
80 | { printk("LINE:%d Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); \ | |
81 | if ((x)==(y)) udelay(5); } | |
82 | #define REMOVE(w,x,y,z) \ | |
83 | { printk("LINE:%d Removing: %p->%p %p->%p \n", __LINE__, \ | |
84 | (void*)(w), (void*)(x), (void*)(y), (void*)(z)); \ | |
85 | if ((x)==(y)) udelay(5); } | |
86 | #else | |
87 | #define LIST(x,y) | |
88 | #define REMOVE(w,x,y,z) | |
89 | #endif | |
90 | ||
91 | #ifndef notyet | |
92 | #undef LINKED | |
93 | #endif | |
94 | ||
95 | /* | |
96 | * Design | |
97 | * Issues : | |
98 | * | |
99 | * The other Linux SCSI drivers were written when Linux was Intel PC-only, | |
100 | * and specifically for each board rather than each chip. This makes their | |
101 | * adaptation to platforms like the Mac (Some of which use NCR5380's) | |
102 | * more difficult than it has to be. | |
103 | * | |
104 | * Also, many of the SCSI drivers were written before the command queuing | |
105 | * routines were implemented, meaning their implementations of queued | |
106 | * commands were hacked on rather than designed in from the start. | |
107 | * | |
108 | * When I designed the Linux SCSI drivers I figured that | |
109 | * while having two different SCSI boards in a system might be useful | |
110 | * for debugging things, two of the same type wouldn't be used. | |
111 | * Well, I was wrong and a number of users have mailed me about running | |
112 | * multiple high-performance SCSI boards in a server. | |
113 | * | |
114 | * Finally, when I get questions from users, I have no idea what | |
115 | * revision of my driver they are running. | |
116 | * | |
117 | * This driver attempts to address these problems : | |
118 | * This is a generic 5380 driver. To use it on a different platform, | |
119 | * one simply writes appropriate system specific macros (ie, data | |
120 | * transfer - some PC's will use the I/O bus, 68K's must use | |
121 | * memory mapped) and drops this file in their 'C' wrapper. | |
122 | * | |
123 | * As far as command queueing, two queues are maintained for | |
124 | * each 5380 in the system - commands that haven't been issued yet, | |
125 | * and commands that are currently executing. This means that an | |
126 | * unlimited number of commands may be queued, letting | |
127 | * more commands propagate from the higher driver levels giving higher | |
128 | * throughput. Note that both I_T_L and I_T_L_Q nexuses are supported, | |
129 | * allowing multiple commands to propagate all the way to a SCSI-II device | |
130 | * while a command is already executing. | |
131 | * | |
132 | * To solve the multiple-boards-in-the-same-system problem, | |
133 | * there is a separate instance structure for each instance | |
134 | * of a 5380 in the system. So, multiple NCR5380 drivers will | |
135 | * be able to coexist with appropriate changes to the high level | |
136 | * SCSI code. | |
137 | * | |
138 | * A NCR5380_PUBLIC_REVISION macro is provided, with the release | |
139 | * number (updated for each public release) printed by the | |
140 | * NCR5380_print_options command, which should be called from the | |
141 | * wrapper detect function, so that I know what release of the driver | |
142 | * users are using. | |
143 | * | |
144 | * Issues specific to the NCR5380 : | |
145 | * | |
146 | * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead | |
147 | * piece of hardware that requires you to sit in a loop polling for | |
148 | * the REQ signal as long as you are connected. Some devices are | |
149 | * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect | |
150 | * while doing long seek operations. | |
151 | * | |
152 | * The workaround for this is to keep track of devices that have | |
153 | * disconnected. If the device hasn't disconnected, for commands that | |
154 | * should disconnect, we do something like | |
155 | * | |
156 | * while (!REQ is asserted) { sleep for N usecs; poll for M usecs } | |
157 | * | |
158 | * Some tweaking of N and M needs to be done. An algorithm based | |
159 | * on "time to data" would give the best results as long as short time | |
160 | * to datas (ie, on the same track) were considered, however these | |
161 | * broken devices are the exception rather than the rule and I'd rather | |
162 | * spend my time optimizing for the normal case. | |
163 | * | |
164 | * Architecture : | |
165 | * | |
166 | * At the heart of the design is a coroutine, NCR5380_main, | |
167 | * which is started when not running by the interrupt handler, | |
168 | * timer, and queue command function. It attempts to establish | |
169 | * I_T_L or I_T_L_Q nexuses by removing the commands from the | |
170 | * issue queue and calling NCR5380_select() if a nexus | |
171 | * is not established. | |
172 | * | |
173 | * Once a nexus is established, the NCR5380_information_transfer() | |
174 | * phase goes through the various phases as instructed by the target. | |
175 | * if the target goes into MSG IN and sends a DISCONNECT message, | |
176 | * the command structure is placed into the per instance disconnected | |
177 | * queue, and NCR5380_main tries to find more work. If USLEEP | |
178 | * was defined, and the target is idle for too long, the system | |
179 | * will try to sleep. | |
180 | * | |
181 | * If a command has disconnected, eventually an interrupt will trigger, | |
182 | * calling NCR5380_intr() which will in turn call NCR5380_reselect | |
183 | * to reestablish a nexus. This will run main if necessary. | |
184 | * | |
185 | * On command termination, the done function will be called as | |
186 | * appropriate. | |
187 | * | |
188 | * SCSI pointers are maintained in the SCp field of SCSI command | |
189 | * structures, being initialized after the command is connected | |
190 | * in NCR5380_select, and set as appropriate in NCR5380_information_transfer. | |
191 | * Note that in violation of the standard, an implicit SAVE POINTERS operation | |
192 | * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS. | |
193 | */ | |
194 | ||
195 | /* | |
196 | * Using this file : | |
197 | * This file a skeleton Linux SCSI driver for the NCR 5380 series | |
198 | * of chips. To use it, you write an architecture specific functions | |
199 | * and macros and include this file in your driver. | |
200 | * | |
201 | * These macros control options : | |
202 | * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically | |
203 | * for commands that return with a CHECK CONDITION status. | |
204 | * | |
205 | * LINKED - if defined, linked commands are supported. | |
206 | * | |
207 | * REAL_DMA - if defined, REAL DMA is used during the data transfer phases. | |
208 | * | |
209 | * SUPPORT_TAGS - if defined, SCSI-2 tagged queuing is used where possible | |
210 | * | |
211 | * These macros MUST be defined : | |
212 | * | |
213 | * NCR5380_read(register) - read from the specified register | |
214 | * | |
215 | * NCR5380_write(register, value) - write to the specific register | |
216 | * | |
217 | * Either real DMA *or* pseudo DMA may be implemented | |
218 | * REAL functions : | |
219 | * NCR5380_REAL_DMA should be defined if real DMA is to be used. | |
220 | * Note that the DMA setup functions should return the number of bytes | |
221 | * that they were able to program the controller for. | |
222 | * | |
223 | * Also note that generic i386/PC versions of these macros are | |
224 | * available as NCR5380_i386_dma_write_setup, | |
225 | * NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual. | |
226 | * | |
227 | * NCR5380_dma_write_setup(instance, src, count) - initialize | |
228 | * NCR5380_dma_read_setup(instance, dst, count) - initialize | |
229 | * NCR5380_dma_residual(instance); - residual count | |
230 | * | |
231 | * PSEUDO functions : | |
232 | * NCR5380_pwrite(instance, src, count) | |
233 | * NCR5380_pread(instance, dst, count); | |
234 | * | |
235 | * If nothing specific to this implementation needs doing (ie, with external | |
236 | * hardware), you must also define | |
237 | * | |
238 | * NCR5380_queue_command | |
239 | * NCR5380_reset | |
240 | * NCR5380_abort | |
241 | * NCR5380_proc_info | |
242 | * | |
243 | * to be the global entry points into the specific driver, ie | |
244 | * #define NCR5380_queue_command t128_queue_command. | |
245 | * | |
246 | * If this is not done, the routines will be defined as static functions | |
247 | * with the NCR5380* names and the user must provide a globally | |
248 | * accessible wrapper function. | |
249 | * | |
250 | * The generic driver is initialized by calling NCR5380_init(instance), | |
251 | * after setting the appropriate host specific fields and ID. If the | |
252 | * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance, | |
253 | * possible) function may be used. Before the specific driver initialization | |
254 | * code finishes, NCR5380_print_options should be called. | |
255 | */ | |
256 | ||
257 | static struct Scsi_Host *first_instance = NULL; | |
d0be4a7d | 258 | static struct scsi_host_template *the_template = NULL; |
1da177e4 LT |
259 | |
260 | /* Macros ease life... :-) */ | |
261 | #define SETUP_HOSTDATA(in) \ | |
262 | struct NCR5380_hostdata *hostdata = \ | |
263 | (struct NCR5380_hostdata *)(in)->hostdata | |
264 | #define HOSTDATA(in) ((struct NCR5380_hostdata *)(in)->hostdata) | |
265 | ||
266 | #define NEXT(cmd) ((Scsi_Cmnd *)((cmd)->host_scribble)) | |
267 | #define NEXTADDR(cmd) ((Scsi_Cmnd **)&((cmd)->host_scribble)) | |
268 | ||
269 | #define HOSTNO instance->host_no | |
270 | #define H_NO(cmd) (cmd)->device->host->host_no | |
271 | ||
272 | #ifdef SUPPORT_TAGS | |
273 | ||
274 | /* | |
275 | * Functions for handling tagged queuing | |
276 | * ===================================== | |
277 | * | |
278 | * ++roman (01/96): Now I've implemented SCSI-2 tagged queuing. Some notes: | |
279 | * | |
280 | * Using consecutive numbers for the tags is no good idea in my eyes. There | |
281 | * could be wrong re-usings if the counter (8 bit!) wraps and some early | |
282 | * command has been preempted for a long time. My solution: a bitfield for | |
283 | * remembering used tags. | |
284 | * | |
285 | * There's also the problem that each target has a certain queue size, but we | |
286 | * cannot know it in advance :-( We just see a QUEUE_FULL status being | |
287 | * returned. So, in this case, the driver internal queue size assumption is | |
288 | * reduced to the number of active tags if QUEUE_FULL is returned by the | |
289 | * target. The command is returned to the mid-level, but with status changed | |
290 | * to BUSY, since --as I've seen-- the mid-level can't handle QUEUE_FULL | |
291 | * correctly. | |
292 | * | |
293 | * We're also not allowed running tagged commands as long as an untagged | |
294 | * command is active. And REQUEST SENSE commands after a contingent allegiance | |
295 | * condition _must_ be untagged. To keep track whether an untagged command has | |
296 | * been issued, the host->busy array is still employed, as it is without | |
297 | * support for tagged queuing. | |
298 | * | |
299 | * One could suspect that there are possible race conditions between | |
300 | * is_lun_busy(), cmd_get_tag() and cmd_free_tag(). But I think this isn't the | |
301 | * case: is_lun_busy() and cmd_get_tag() are both called from NCR5380_main(), | |
302 | * which already guaranteed to be running at most once. It is also the only | |
303 | * place where tags/LUNs are allocated. So no other allocation can slip | |
304 | * between that pair, there could only happen a reselection, which can free a | |
305 | * tag, but that doesn't hurt. Only the sequence in cmd_free_tag() becomes | |
306 | * important: the tag bit must be cleared before 'nr_allocated' is decreased. | |
307 | */ | |
308 | ||
309 | /* -1 for TAG_NONE is not possible with unsigned char cmd->tag */ | |
310 | #undef TAG_NONE | |
311 | #define TAG_NONE 0xff | |
312 | ||
313 | typedef struct { | |
314 | DECLARE_BITMAP(allocated, MAX_TAGS); | |
315 | int nr_allocated; | |
316 | int queue_size; | |
317 | } TAG_ALLOC; | |
318 | ||
319 | static TAG_ALLOC TagAlloc[8][8]; /* 8 targets and 8 LUNs */ | |
320 | ||
321 | ||
322 | static void __init init_tags( void ) | |
323 | { | |
324 | int target, lun; | |
325 | TAG_ALLOC *ta; | |
326 | ||
327 | if (!setup_use_tagged_queuing) | |
328 | return; | |
329 | ||
330 | for( target = 0; target < 8; ++target ) { | |
331 | for( lun = 0; lun < 8; ++lun ) { | |
332 | ta = &TagAlloc[target][lun]; | |
333 | bitmap_zero(ta->allocated, MAX_TAGS); | |
334 | ta->nr_allocated = 0; | |
335 | /* At the beginning, assume the maximum queue size we could | |
336 | * support (MAX_TAGS). This value will be decreased if the target | |
337 | * returns QUEUE_FULL status. | |
338 | */ | |
339 | ta->queue_size = MAX_TAGS; | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
344 | ||
345 | /* Check if we can issue a command to this LUN: First see if the LUN is marked | |
346 | * busy by an untagged command. If the command should use tagged queuing, also | |
347 | * check that there is a free tag and the target's queue won't overflow. This | |
348 | * function should be called with interrupts disabled to avoid race | |
349 | * conditions. | |
350 | */ | |
351 | ||
352 | static int is_lun_busy( Scsi_Cmnd *cmd, int should_be_tagged ) | |
353 | { | |
354 | SETUP_HOSTDATA(cmd->device->host); | |
355 | ||
356 | if (hostdata->busy[cmd->device->id] & (1 << cmd->device->lun)) | |
357 | return( 1 ); | |
358 | if (!should_be_tagged || | |
359 | !setup_use_tagged_queuing || !cmd->device->tagged_supported) | |
360 | return( 0 ); | |
361 | if (TagAlloc[cmd->device->id][cmd->device->lun].nr_allocated >= | |
362 | TagAlloc[cmd->device->id][cmd->device->lun].queue_size ) { | |
363 | TAG_PRINTK( "scsi%d: target %d lun %d: no free tags\n", | |
364 | H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
365 | return( 1 ); | |
366 | } | |
367 | return( 0 ); | |
368 | } | |
369 | ||
370 | ||
371 | /* Allocate a tag for a command (there are no checks anymore, check_lun_busy() | |
372 | * must be called before!), or reserve the LUN in 'busy' if the command is | |
373 | * untagged. | |
374 | */ | |
375 | ||
376 | static void cmd_get_tag( Scsi_Cmnd *cmd, int should_be_tagged ) | |
377 | { | |
378 | SETUP_HOSTDATA(cmd->device->host); | |
379 | ||
380 | /* If we or the target don't support tagged queuing, allocate the LUN for | |
381 | * an untagged command. | |
382 | */ | |
383 | if (!should_be_tagged || | |
384 | !setup_use_tagged_queuing || !cmd->device->tagged_supported) { | |
385 | cmd->tag = TAG_NONE; | |
386 | hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun); | |
387 | TAG_PRINTK( "scsi%d: target %d lun %d now allocated by untagged " | |
388 | "command\n", H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
389 | } | |
390 | else { | |
391 | TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun]; | |
392 | ||
393 | cmd->tag = find_first_zero_bit( ta->allocated, MAX_TAGS ); | |
394 | set_bit( cmd->tag, ta->allocated ); | |
395 | ta->nr_allocated++; | |
396 | TAG_PRINTK( "scsi%d: using tag %d for target %d lun %d " | |
397 | "(now %d tags in use)\n", | |
398 | H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun, | |
399 | ta->nr_allocated ); | |
400 | } | |
401 | } | |
402 | ||
403 | ||
404 | /* Mark the tag of command 'cmd' as free, or in case of an untagged command, | |
405 | * unlock the LUN. | |
406 | */ | |
407 | ||
408 | static void cmd_free_tag( Scsi_Cmnd *cmd ) | |
409 | { | |
410 | SETUP_HOSTDATA(cmd->device->host); | |
411 | ||
412 | if (cmd->tag == TAG_NONE) { | |
413 | hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun); | |
414 | TAG_PRINTK( "scsi%d: target %d lun %d untagged cmd finished\n", | |
415 | H_NO(cmd), cmd->device->id, cmd->device->lun ); | |
416 | } | |
417 | else if (cmd->tag >= MAX_TAGS) { | |
418 | printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!\n", | |
419 | H_NO(cmd), cmd->tag ); | |
420 | } | |
421 | else { | |
422 | TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun]; | |
423 | clear_bit( cmd->tag, ta->allocated ); | |
424 | ta->nr_allocated--; | |
425 | TAG_PRINTK( "scsi%d: freed tag %d for target %d lun %d\n", | |
426 | H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun ); | |
427 | } | |
428 | } | |
429 | ||
430 | ||
431 | static void free_all_tags( void ) | |
432 | { | |
433 | int target, lun; | |
434 | TAG_ALLOC *ta; | |
435 | ||
436 | if (!setup_use_tagged_queuing) | |
437 | return; | |
438 | ||
439 | for( target = 0; target < 8; ++target ) { | |
440 | for( lun = 0; lun < 8; ++lun ) { | |
441 | ta = &TagAlloc[target][lun]; | |
442 | bitmap_zero(ta->allocated, MAX_TAGS); | |
443 | ta->nr_allocated = 0; | |
444 | } | |
445 | } | |
446 | } | |
447 | ||
448 | #endif /* SUPPORT_TAGS */ | |
449 | ||
450 | ||
451 | /* | |
452 | * Function: void merge_contiguous_buffers( Scsi_Cmnd *cmd ) | |
453 | * | |
454 | * Purpose: Try to merge several scatter-gather requests into one DMA | |
455 | * transfer. This is possible if the scatter buffers lie on | |
456 | * physical contiguous addresses. | |
457 | * | |
458 | * Parameters: Scsi_Cmnd *cmd | |
459 | * The command to work on. The first scatter buffer's data are | |
460 | * assumed to be already transfered into ptr/this_residual. | |
461 | */ | |
462 | ||
463 | static void merge_contiguous_buffers( Scsi_Cmnd *cmd ) | |
464 | { | |
465 | unsigned long endaddr; | |
466 | #if (NDEBUG & NDEBUG_MERGING) | |
467 | unsigned long oldlen = cmd->SCp.this_residual; | |
468 | int cnt = 1; | |
469 | #endif | |
470 | ||
471 | for (endaddr = virt_to_phys(cmd->SCp.ptr + cmd->SCp.this_residual - 1) + 1; | |
472 | cmd->SCp.buffers_residual && | |
473 | virt_to_phys(page_address(cmd->SCp.buffer[1].page)+ | |
474 | cmd->SCp.buffer[1].offset) == endaddr; ) { | |
475 | MER_PRINTK("VTOP(%p) == %08lx -> merging\n", | |
476 | cmd->SCp.buffer[1].address, endaddr); | |
477 | #if (NDEBUG & NDEBUG_MERGING) | |
478 | ++cnt; | |
479 | #endif | |
480 | ++cmd->SCp.buffer; | |
481 | --cmd->SCp.buffers_residual; | |
482 | cmd->SCp.this_residual += cmd->SCp.buffer->length; | |
483 | endaddr += cmd->SCp.buffer->length; | |
484 | } | |
485 | #if (NDEBUG & NDEBUG_MERGING) | |
486 | if (oldlen != cmd->SCp.this_residual) | |
487 | MER_PRINTK("merged %d buffers from %p, new length %08x\n", | |
488 | cnt, cmd->SCp.ptr, cmd->SCp.this_residual); | |
489 | #endif | |
490 | } | |
491 | ||
492 | /* | |
493 | * Function : void initialize_SCp(Scsi_Cmnd *cmd) | |
494 | * | |
495 | * Purpose : initialize the saved data pointers for cmd to point to the | |
496 | * start of the buffer. | |
497 | * | |
498 | * Inputs : cmd - Scsi_Cmnd structure to have pointers reset. | |
499 | */ | |
500 | ||
501 | static __inline__ void initialize_SCp(Scsi_Cmnd *cmd) | |
502 | { | |
503 | /* | |
504 | * Initialize the Scsi Pointer field so that all of the commands in the | |
505 | * various queues are valid. | |
506 | */ | |
507 | ||
508 | if (cmd->use_sg) { | |
509 | cmd->SCp.buffer = (struct scatterlist *) cmd->buffer; | |
510 | cmd->SCp.buffers_residual = cmd->use_sg - 1; | |
511 | cmd->SCp.ptr = (char *)page_address(cmd->SCp.buffer->page)+ | |
512 | cmd->SCp.buffer->offset; | |
513 | cmd->SCp.this_residual = cmd->SCp.buffer->length; | |
514 | /* ++roman: Try to merge some scatter-buffers if they are at | |
515 | * contiguous physical addresses. | |
516 | */ | |
517 | merge_contiguous_buffers( cmd ); | |
518 | } else { | |
519 | cmd->SCp.buffer = NULL; | |
520 | cmd->SCp.buffers_residual = 0; | |
521 | cmd->SCp.ptr = (char *) cmd->request_buffer; | |
522 | cmd->SCp.this_residual = cmd->request_bufflen; | |
523 | } | |
524 | } | |
525 | ||
526 | #include <linux/config.h> | |
527 | #include <linux/delay.h> | |
528 | ||
529 | #if NDEBUG | |
530 | static struct { | |
531 | unsigned char mask; | |
532 | const char * name;} | |
533 | signals[] = {{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" }, | |
534 | { SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD, "CD" }, { SR_IO, "IO" }, | |
535 | { SR_SEL, "SEL" }, {0, NULL}}, | |
536 | basrs[] = {{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}}, | |
537 | icrs[] = {{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"}, | |
538 | {ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"}, | |
539 | {ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"}, | |
540 | {0, NULL}}, | |
541 | mrs[] = {{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"}, | |
542 | {MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR, | |
543 | "MODE PARITY INTR"}, {MR_ENABLE_EOP_INTR,"MODE EOP INTR"}, | |
544 | {MR_MONITOR_BSY, "MODE MONITOR BSY"}, | |
545 | {MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"}, | |
546 | {0, NULL}}; | |
547 | ||
548 | /* | |
549 | * Function : void NCR5380_print(struct Scsi_Host *instance) | |
550 | * | |
551 | * Purpose : print the SCSI bus signals for debugging purposes | |
552 | * | |
553 | * Input : instance - which NCR5380 | |
554 | */ | |
555 | ||
556 | static void NCR5380_print(struct Scsi_Host *instance) { | |
557 | unsigned char status, data, basr, mr, icr, i; | |
558 | unsigned long flags; | |
559 | ||
560 | local_irq_save(flags); | |
561 | data = NCR5380_read(CURRENT_SCSI_DATA_REG); | |
562 | status = NCR5380_read(STATUS_REG); | |
563 | mr = NCR5380_read(MODE_REG); | |
564 | icr = NCR5380_read(INITIATOR_COMMAND_REG); | |
565 | basr = NCR5380_read(BUS_AND_STATUS_REG); | |
566 | local_irq_restore(flags); | |
567 | printk("STATUS_REG: %02x ", status); | |
568 | for (i = 0; signals[i].mask ; ++i) | |
569 | if (status & signals[i].mask) | |
570 | printk(",%s", signals[i].name); | |
571 | printk("\nBASR: %02x ", basr); | |
572 | for (i = 0; basrs[i].mask ; ++i) | |
573 | if (basr & basrs[i].mask) | |
574 | printk(",%s", basrs[i].name); | |
575 | printk("\nICR: %02x ", icr); | |
576 | for (i = 0; icrs[i].mask; ++i) | |
577 | if (icr & icrs[i].mask) | |
578 | printk(",%s", icrs[i].name); | |
579 | printk("\nMODE: %02x ", mr); | |
580 | for (i = 0; mrs[i].mask; ++i) | |
581 | if (mr & mrs[i].mask) | |
582 | printk(",%s", mrs[i].name); | |
583 | printk("\n"); | |
584 | } | |
585 | ||
586 | static struct { | |
587 | unsigned char value; | |
588 | const char *name; | |
589 | } phases[] = { | |
590 | {PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"}, | |
591 | {PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"}, | |
592 | {PHASE_UNKNOWN, "UNKNOWN"}}; | |
593 | ||
594 | /* | |
595 | * Function : void NCR5380_print_phase(struct Scsi_Host *instance) | |
596 | * | |
597 | * Purpose : print the current SCSI phase for debugging purposes | |
598 | * | |
599 | * Input : instance - which NCR5380 | |
600 | */ | |
601 | ||
602 | static void NCR5380_print_phase(struct Scsi_Host *instance) | |
603 | { | |
604 | unsigned char status; | |
605 | int i; | |
606 | ||
607 | status = NCR5380_read(STATUS_REG); | |
608 | if (!(status & SR_REQ)) | |
609 | printk(KERN_DEBUG "scsi%d: REQ not asserted, phase unknown.\n", HOSTNO); | |
610 | else { | |
611 | for (i = 0; (phases[i].value != PHASE_UNKNOWN) && | |
612 | (phases[i].value != (status & PHASE_MASK)); ++i); | |
613 | printk(KERN_DEBUG "scsi%d: phase %s\n", HOSTNO, phases[i].name); | |
614 | } | |
615 | } | |
616 | ||
617 | #else /* !NDEBUG */ | |
618 | ||
619 | /* dummies... */ | |
620 | __inline__ void NCR5380_print(struct Scsi_Host *instance) { }; | |
621 | __inline__ void NCR5380_print_phase(struct Scsi_Host *instance) { }; | |
622 | ||
623 | #endif | |
624 | ||
625 | /* | |
626 | * ++roman: New scheme of calling NCR5380_main() | |
627 | * | |
628 | * If we're not in an interrupt, we can call our main directly, it cannot be | |
629 | * already running. Else, we queue it on a task queue, if not 'main_running' | |
630 | * tells us that a lower level is already executing it. This way, | |
631 | * 'main_running' needs not be protected in a special way. | |
632 | * | |
633 | * queue_main() is a utility function for putting our main onto the task | |
634 | * queue, if main_running is false. It should be called only from a | |
635 | * interrupt or bottom half. | |
636 | */ | |
637 | ||
638 | #include <linux/workqueue.h> | |
639 | #include <linux/interrupt.h> | |
640 | ||
641 | static volatile int main_running = 0; | |
642 | static DECLARE_WORK(NCR5380_tqueue, (void (*)(void*))NCR5380_main, NULL); | |
643 | ||
644 | static __inline__ void queue_main(void) | |
645 | { | |
646 | if (!main_running) { | |
647 | /* If in interrupt and NCR5380_main() not already running, | |
648 | queue it on the 'immediate' task queue, to be processed | |
649 | immediately after the current interrupt processing has | |
650 | finished. */ | |
651 | schedule_work(&NCR5380_tqueue); | |
652 | } | |
653 | /* else: nothing to do: the running NCR5380_main() will pick up | |
654 | any newly queued command. */ | |
655 | } | |
656 | ||
657 | ||
658 | static inline void NCR5380_all_init (void) | |
659 | { | |
660 | static int done = 0; | |
661 | if (!done) { | |
662 | INI_PRINTK("scsi : NCR5380_all_init()\n"); | |
663 | done = 1; | |
664 | } | |
665 | } | |
666 | ||
667 | ||
668 | /* | |
669 | * Function : void NCR58380_print_options (struct Scsi_Host *instance) | |
670 | * | |
671 | * Purpose : called by probe code indicating the NCR5380 driver | |
672 | * options that were selected. | |
673 | * | |
674 | * Inputs : instance, pointer to this instance. Unused. | |
675 | */ | |
676 | ||
677 | static void __init NCR5380_print_options (struct Scsi_Host *instance) | |
678 | { | |
679 | printk(" generic options" | |
680 | #ifdef AUTOSENSE | |
681 | " AUTOSENSE" | |
682 | #endif | |
683 | #ifdef REAL_DMA | |
684 | " REAL DMA" | |
685 | #endif | |
686 | #ifdef PARITY | |
687 | " PARITY" | |
688 | #endif | |
689 | #ifdef SUPPORT_TAGS | |
690 | " SCSI-2 TAGGED QUEUING" | |
691 | #endif | |
692 | ); | |
693 | printk(" generic release=%d", NCR5380_PUBLIC_RELEASE); | |
694 | } | |
695 | ||
696 | /* | |
697 | * Function : void NCR5380_print_status (struct Scsi_Host *instance) | |
698 | * | |
699 | * Purpose : print commands in the various queues, called from | |
700 | * NCR5380_abort and NCR5380_debug to aid debugging. | |
701 | * | |
702 | * Inputs : instance, pointer to this instance. | |
703 | */ | |
704 | ||
705 | static void NCR5380_print_status (struct Scsi_Host *instance) | |
706 | { | |
707 | char *pr_bfr; | |
708 | char *start; | |
709 | int len; | |
710 | ||
711 | NCR_PRINT(NDEBUG_ANY); | |
712 | NCR_PRINT_PHASE(NDEBUG_ANY); | |
713 | ||
714 | pr_bfr = (char *) __get_free_page(GFP_ATOMIC); | |
715 | if (!pr_bfr) { | |
716 | printk("NCR5380_print_status: no memory for print buffer\n"); | |
717 | return; | |
718 | } | |
719 | len = NCR5380_proc_info(pr_bfr, &start, 0, PAGE_SIZE, HOSTNO, 0); | |
720 | pr_bfr[len] = 0; | |
721 | printk("\n%s\n", pr_bfr); | |
722 | free_page((unsigned long) pr_bfr); | |
723 | } | |
724 | ||
725 | ||
726 | /******************************************/ | |
727 | /* | |
728 | * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED] | |
729 | * | |
730 | * *buffer: I/O buffer | |
731 | * **start: if inout == FALSE pointer into buffer where user read should start | |
732 | * offset: current offset | |
733 | * length: length of buffer | |
734 | * hostno: Scsi_Host host_no | |
735 | * inout: TRUE - user is writing; FALSE - user is reading | |
736 | * | |
737 | * Return the number of bytes read from or written | |
738 | */ | |
739 | ||
740 | #undef SPRINTF | |
741 | #define SPRINTF(fmt,args...) \ | |
742 | do { if (pos + strlen(fmt) + 20 /* slop */ < buffer + length) \ | |
743 | pos += sprintf(pos, fmt , ## args); } while(0) | |
744 | static | |
745 | char *lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length); | |
746 | ||
747 | static | |
748 | int NCR5380_proc_info (struct Scsi_Host *instance, char *buffer, char **start, off_t offset, | |
749 | int length, int inout) | |
750 | { | |
751 | char *pos = buffer; | |
752 | struct NCR5380_hostdata *hostdata; | |
753 | Scsi_Cmnd *ptr; | |
754 | unsigned long flags; | |
755 | off_t begin = 0; | |
756 | #define check_offset() \ | |
757 | do { \ | |
758 | if (pos - buffer < offset - begin) { \ | |
759 | begin += pos - buffer; \ | |
760 | pos = buffer; \ | |
761 | } \ | |
762 | } while (0) | |
763 | ||
764 | hostdata = (struct NCR5380_hostdata *)instance->hostdata; | |
765 | ||
766 | if (inout) { /* Has data been written to the file ? */ | |
767 | return(-ENOSYS); /* Currently this is a no-op */ | |
768 | } | |
769 | SPRINTF("NCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE); | |
770 | check_offset(); | |
771 | local_irq_save(flags); | |
772 | SPRINTF("NCR5380: coroutine is%s running.\n", main_running ? "" : "n't"); | |
773 | check_offset(); | |
774 | if (!hostdata->connected) | |
775 | SPRINTF("scsi%d: no currently connected command\n", HOSTNO); | |
776 | else | |
777 | pos = lprint_Scsi_Cmnd ((Scsi_Cmnd *) hostdata->connected, | |
778 | pos, buffer, length); | |
779 | SPRINTF("scsi%d: issue_queue\n", HOSTNO); | |
780 | check_offset(); | |
781 | for (ptr = (Scsi_Cmnd *) hostdata->issue_queue; ptr; ptr = NEXT(ptr)) { | |
782 | pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length); | |
783 | check_offset(); | |
784 | } | |
785 | ||
786 | SPRINTF("scsi%d: disconnected_queue\n", HOSTNO); | |
787 | check_offset(); | |
788 | for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr; | |
789 | ptr = NEXT(ptr)) { | |
790 | pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length); | |
791 | check_offset(); | |
792 | } | |
793 | ||
794 | local_irq_restore(flags); | |
795 | *start = buffer + (offset - begin); | |
796 | if (pos - buffer < offset - begin) | |
797 | return 0; | |
798 | else if (pos - buffer - (offset - begin) < length) | |
799 | return pos - buffer - (offset - begin); | |
800 | return length; | |
801 | } | |
802 | ||
803 | static char * | |
804 | lprint_Scsi_Cmnd (Scsi_Cmnd *cmd, char *pos, char *buffer, int length) | |
805 | { | |
806 | int i, s; | |
807 | unsigned char *command; | |
808 | SPRINTF("scsi%d: destination target %d, lun %d\n", | |
809 | H_NO(cmd), cmd->device->id, cmd->device->lun); | |
810 | SPRINTF(" command = "); | |
811 | command = cmd->cmnd; | |
812 | SPRINTF("%2d (0x%02x)", command[0], command[0]); | |
813 | for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i) | |
814 | SPRINTF(" %02x", command[i]); | |
815 | SPRINTF("\n"); | |
816 | return pos; | |
817 | } | |
818 | ||
819 | ||
820 | /* | |
821 | * Function : void NCR5380_init (struct Scsi_Host *instance) | |
822 | * | |
823 | * Purpose : initializes *instance and corresponding 5380 chip. | |
824 | * | |
825 | * Inputs : instance - instantiation of the 5380 driver. | |
826 | * | |
827 | * Notes : I assume that the host, hostno, and id bits have been | |
828 | * set correctly. I don't care about the irq and other fields. | |
829 | * | |
830 | */ | |
831 | ||
832 | static int NCR5380_init (struct Scsi_Host *instance, int flags) | |
833 | { | |
834 | int i; | |
835 | SETUP_HOSTDATA(instance); | |
836 | ||
837 | NCR5380_all_init(); | |
838 | ||
839 | hostdata->aborted = 0; | |
840 | hostdata->id_mask = 1 << instance->this_id; | |
841 | hostdata->id_higher_mask = 0; | |
842 | for (i = hostdata->id_mask; i <= 0x80; i <<= 1) | |
843 | if (i > hostdata->id_mask) | |
844 | hostdata->id_higher_mask |= i; | |
845 | for (i = 0; i < 8; ++i) | |
846 | hostdata->busy[i] = 0; | |
847 | #ifdef SUPPORT_TAGS | |
848 | init_tags(); | |
849 | #endif | |
850 | #if defined (REAL_DMA) | |
851 | hostdata->dma_len = 0; | |
852 | #endif | |
853 | hostdata->targets_present = 0; | |
854 | hostdata->connected = NULL; | |
855 | hostdata->issue_queue = NULL; | |
856 | hostdata->disconnected_queue = NULL; | |
857 | hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT; | |
858 | ||
859 | if (!the_template) { | |
860 | the_template = instance->hostt; | |
861 | first_instance = instance; | |
862 | } | |
863 | ||
864 | ||
865 | #ifndef AUTOSENSE | |
866 | if ((instance->cmd_per_lun > 1) || (instance->can_queue > 1)) | |
867 | printk("scsi%d: WARNING : support for multiple outstanding commands enabled\n" | |
868 | " without AUTOSENSE option, contingent allegiance conditions may\n" | |
869 | " be incorrectly cleared.\n", HOSTNO); | |
870 | #endif /* def AUTOSENSE */ | |
871 | ||
872 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
873 | NCR5380_write(MODE_REG, MR_BASE); | |
874 | NCR5380_write(TARGET_COMMAND_REG, 0); | |
875 | NCR5380_write(SELECT_ENABLE_REG, 0); | |
876 | ||
877 | return 0; | |
878 | } | |
879 | ||
880 | /* | |
881 | * Function : int NCR5380_queue_command (Scsi_Cmnd *cmd, | |
882 | * void (*done)(Scsi_Cmnd *)) | |
883 | * | |
884 | * Purpose : enqueues a SCSI command | |
885 | * | |
886 | * Inputs : cmd - SCSI command, done - function called on completion, with | |
887 | * a pointer to the command descriptor. | |
888 | * | |
889 | * Returns : 0 | |
890 | * | |
891 | * Side effects : | |
892 | * cmd is added to the per instance issue_queue, with minor | |
893 | * twiddling done to the host specific fields of cmd. If the | |
894 | * main coroutine is not running, it is restarted. | |
895 | * | |
896 | */ | |
897 | ||
898 | static | |
899 | int NCR5380_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *)) | |
900 | { | |
901 | SETUP_HOSTDATA(cmd->device->host); | |
902 | Scsi_Cmnd *tmp; | |
903 | int oldto; | |
904 | unsigned long flags; | |
905 | extern int update_timeout(Scsi_Cmnd * SCset, int timeout); | |
906 | ||
907 | #if (NDEBUG & NDEBUG_NO_WRITE) | |
908 | switch (cmd->cmnd[0]) { | |
909 | case WRITE_6: | |
910 | case WRITE_10: | |
911 | printk(KERN_NOTICE "scsi%d: WRITE attempted with NO_WRITE debugging flag set\n", | |
912 | H_NO(cmd)); | |
913 | cmd->result = (DID_ERROR << 16); | |
914 | done(cmd); | |
915 | return 0; | |
916 | } | |
917 | #endif /* (NDEBUG & NDEBUG_NO_WRITE) */ | |
918 | ||
919 | ||
920 | #ifdef NCR5380_STATS | |
921 | # if 0 | |
922 | if (!hostdata->connected && !hostdata->issue_queue && | |
923 | !hostdata->disconnected_queue) { | |
924 | hostdata->timebase = jiffies; | |
925 | } | |
926 | # endif | |
927 | # ifdef NCR5380_STAT_LIMIT | |
928 | if (cmd->request_bufflen > NCR5380_STAT_LIMIT) | |
929 | # endif | |
930 | switch (cmd->cmnd[0]) | |
931 | { | |
932 | case WRITE: | |
933 | case WRITE_6: | |
934 | case WRITE_10: | |
935 | hostdata->time_write[cmd->device->id] -= (jiffies - hostdata->timebase); | |
936 | hostdata->bytes_write[cmd->device->id] += cmd->request_bufflen; | |
937 | hostdata->pendingw++; | |
938 | break; | |
939 | case READ: | |
940 | case READ_6: | |
941 | case READ_10: | |
942 | hostdata->time_read[cmd->device->id] -= (jiffies - hostdata->timebase); | |
943 | hostdata->bytes_read[cmd->device->id] += cmd->request_bufflen; | |
944 | hostdata->pendingr++; | |
945 | break; | |
946 | } | |
947 | #endif | |
948 | ||
949 | /* | |
950 | * We use the host_scribble field as a pointer to the next command | |
951 | * in a queue | |
952 | */ | |
953 | ||
954 | NEXT(cmd) = NULL; | |
955 | cmd->scsi_done = done; | |
956 | ||
957 | cmd->result = 0; | |
958 | ||
959 | ||
960 | /* | |
961 | * Insert the cmd into the issue queue. Note that REQUEST SENSE | |
962 | * commands are added to the head of the queue since any command will | |
963 | * clear the contingent allegiance condition that exists and the | |
964 | * sense data is only guaranteed to be valid while the condition exists. | |
965 | */ | |
966 | ||
967 | local_irq_save(flags); | |
968 | /* ++guenther: now that the issue queue is being set up, we can lock ST-DMA. | |
969 | * Otherwise a running NCR5380_main may steal the lock. | |
970 | * Lock before actually inserting due to fairness reasons explained in | |
971 | * atari_scsi.c. If we insert first, then it's impossible for this driver | |
972 | * to release the lock. | |
973 | * Stop timer for this command while waiting for the lock, or timeouts | |
974 | * may happen (and they really do), and it's no good if the command doesn't | |
975 | * appear in any of the queues. | |
976 | * ++roman: Just disabling the NCR interrupt isn't sufficient here, | |
977 | * because also a timer int can trigger an abort or reset, which would | |
978 | * alter queues and touch the lock. | |
979 | */ | |
980 | if (!IS_A_TT()) { | |
981 | oldto = update_timeout(cmd, 0); | |
982 | falcon_get_lock(); | |
983 | update_timeout(cmd, oldto); | |
984 | } | |
985 | if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) { | |
986 | LIST(cmd, hostdata->issue_queue); | |
987 | NEXT(cmd) = hostdata->issue_queue; | |
988 | hostdata->issue_queue = cmd; | |
989 | } else { | |
990 | for (tmp = (Scsi_Cmnd *)hostdata->issue_queue; | |
991 | NEXT(tmp); tmp = NEXT(tmp)) | |
992 | ; | |
993 | LIST(cmd, tmp); | |
994 | NEXT(tmp) = cmd; | |
995 | } | |
996 | local_irq_restore(flags); | |
997 | ||
998 | QU_PRINTK("scsi%d: command added to %s of queue\n", H_NO(cmd), | |
999 | (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail"); | |
1000 | ||
1001 | /* If queue_command() is called from an interrupt (real one or bottom | |
1002 | * half), we let queue_main() do the job of taking care about main. If it | |
1003 | * is already running, this is a no-op, else main will be queued. | |
1004 | * | |
1005 | * If we're not in an interrupt, we can call NCR5380_main() | |
1006 | * unconditionally, because it cannot be already running. | |
1007 | */ | |
1008 | if (in_interrupt() || ((flags >> 8) & 7) >= 6) | |
1009 | queue_main(); | |
1010 | else | |
1011 | NCR5380_main(NULL); | |
1012 | return 0; | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * Function : NCR5380_main (void) | |
1017 | * | |
1018 | * Purpose : NCR5380_main is a coroutine that runs as long as more work can | |
1019 | * be done on the NCR5380 host adapters in a system. Both | |
1020 | * NCR5380_queue_command() and NCR5380_intr() will try to start it | |
1021 | * in case it is not running. | |
1022 | * | |
1023 | * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should | |
1024 | * reenable them. This prevents reentrancy and kernel stack overflow. | |
1025 | */ | |
1026 | ||
1027 | static void NCR5380_main (void *bl) | |
1028 | { | |
1029 | Scsi_Cmnd *tmp, *prev; | |
1030 | struct Scsi_Host *instance = first_instance; | |
1031 | struct NCR5380_hostdata *hostdata = HOSTDATA(instance); | |
1032 | int done; | |
1033 | unsigned long flags; | |
1034 | ||
1035 | /* | |
1036 | * We run (with interrupts disabled) until we're sure that none of | |
1037 | * the host adapters have anything that can be done, at which point | |
1038 | * we set main_running to 0 and exit. | |
1039 | * | |
1040 | * Interrupts are enabled before doing various other internal | |
1041 | * instructions, after we've decided that we need to run through | |
1042 | * the loop again. | |
1043 | * | |
1044 | * this should prevent any race conditions. | |
1045 | * | |
1046 | * ++roman: Just disabling the NCR interrupt isn't sufficient here, | |
1047 | * because also a timer int can trigger an abort or reset, which can | |
1048 | * alter queues and touch the Falcon lock. | |
1049 | */ | |
1050 | ||
1051 | /* Tell int handlers main() is now already executing. Note that | |
1052 | no races are possible here. If an int comes in before | |
1053 | 'main_running' is set here, and queues/executes main via the | |
1054 | task queue, it doesn't do any harm, just this instance of main | |
1055 | won't find any work left to do. */ | |
1056 | if (main_running) | |
1057 | return; | |
1058 | main_running = 1; | |
1059 | ||
1060 | local_save_flags(flags); | |
1061 | do { | |
1062 | local_irq_disable(); /* Freeze request queues */ | |
1063 | done = 1; | |
1064 | ||
1065 | if (!hostdata->connected) { | |
1066 | MAIN_PRINTK( "scsi%d: not connected\n", HOSTNO ); | |
1067 | /* | |
1068 | * Search through the issue_queue for a command destined | |
1069 | * for a target that's not busy. | |
1070 | */ | |
1071 | #if (NDEBUG & NDEBUG_LISTS) | |
1072 | for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, prev = NULL; | |
1073 | tmp && (tmp != prev); prev = tmp, tmp = NEXT(tmp)) | |
1074 | ; | |
1075 | /*printk("%p ", tmp);*/ | |
1076 | if ((tmp == prev) && tmp) printk(" LOOP\n");/* else printk("\n");*/ | |
1077 | #endif | |
1078 | for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, | |
1079 | prev = NULL; tmp; prev = tmp, tmp = NEXT(tmp) ) { | |
1080 | ||
1081 | #if (NDEBUG & NDEBUG_LISTS) | |
1082 | if (prev != tmp) | |
1083 | printk("MAIN tmp=%p target=%d busy=%d lun=%d\n", | |
1084 | tmp, tmp->device->id, hostdata->busy[tmp->device->id], | |
1085 | tmp->device->lun); | |
1086 | #endif | |
1087 | /* When we find one, remove it from the issue queue. */ | |
1088 | /* ++guenther: possible race with Falcon locking */ | |
1089 | if ( | |
1090 | #ifdef SUPPORT_TAGS | |
1091 | !is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE) | |
1092 | #else | |
1093 | !(hostdata->busy[tmp->device->id] & (1 << tmp->device->lun)) | |
1094 | #endif | |
1095 | ) { | |
1096 | /* ++guenther: just to be sure, this must be atomic */ | |
1097 | local_irq_disable(); | |
1098 | if (prev) { | |
1099 | REMOVE(prev, NEXT(prev), tmp, NEXT(tmp)); | |
1100 | NEXT(prev) = NEXT(tmp); | |
1101 | } else { | |
1102 | REMOVE(-1, hostdata->issue_queue, tmp, NEXT(tmp)); | |
1103 | hostdata->issue_queue = NEXT(tmp); | |
1104 | } | |
1105 | NEXT(tmp) = NULL; | |
1106 | falcon_dont_release++; | |
1107 | ||
1108 | /* reenable interrupts after finding one */ | |
1109 | local_irq_restore(flags); | |
1110 | ||
1111 | /* | |
1112 | * Attempt to establish an I_T_L nexus here. | |
1113 | * On success, instance->hostdata->connected is set. | |
1114 | * On failure, we must add the command back to the | |
1115 | * issue queue so we can keep trying. | |
1116 | */ | |
1117 | MAIN_PRINTK("scsi%d: main(): command for target %d " | |
1118 | "lun %d removed from issue_queue\n", | |
1119 | HOSTNO, tmp->device->id, tmp->device->lun); | |
1120 | /* | |
1121 | * REQUEST SENSE commands are issued without tagged | |
1122 | * queueing, even on SCSI-II devices because the | |
1123 | * contingent allegiance condition exists for the | |
1124 | * entire unit. | |
1125 | */ | |
1126 | /* ++roman: ...and the standard also requires that | |
1127 | * REQUEST SENSE command are untagged. | |
1128 | */ | |
1129 | ||
1130 | #ifdef SUPPORT_TAGS | |
1131 | cmd_get_tag( tmp, tmp->cmnd[0] != REQUEST_SENSE ); | |
1132 | #endif | |
1133 | if (!NCR5380_select(instance, tmp, | |
1134 | (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE : | |
1135 | TAG_NEXT)) { | |
1136 | falcon_dont_release--; | |
1137 | /* release if target did not response! */ | |
1138 | falcon_release_lock_if_possible( hostdata ); | |
1139 | break; | |
1140 | } else { | |
1141 | local_irq_disable(); | |
1142 | LIST(tmp, hostdata->issue_queue); | |
1143 | NEXT(tmp) = hostdata->issue_queue; | |
1144 | hostdata->issue_queue = tmp; | |
1145 | #ifdef SUPPORT_TAGS | |
1146 | cmd_free_tag( tmp ); | |
1147 | #endif | |
1148 | falcon_dont_release--; | |
1149 | local_irq_restore(flags); | |
1150 | MAIN_PRINTK("scsi%d: main(): select() failed, " | |
1151 | "returned to issue_queue\n", HOSTNO); | |
1152 | if (hostdata->connected) | |
1153 | break; | |
1154 | } | |
1155 | } /* if target/lun/target queue is not busy */ | |
1156 | } /* for issue_queue */ | |
1157 | } /* if (!hostdata->connected) */ | |
1158 | ||
1159 | if (hostdata->connected | |
1160 | #ifdef REAL_DMA | |
1161 | && !hostdata->dma_len | |
1162 | #endif | |
1163 | ) { | |
1164 | local_irq_restore(flags); | |
1165 | MAIN_PRINTK("scsi%d: main: performing information transfer\n", | |
1166 | HOSTNO); | |
1167 | NCR5380_information_transfer(instance); | |
1168 | MAIN_PRINTK("scsi%d: main: done set false\n", HOSTNO); | |
1169 | done = 0; | |
1170 | } | |
1171 | } while (!done); | |
1172 | ||
1173 | /* Better allow ints _after_ 'main_running' has been cleared, else | |
1174 | an interrupt could believe we'll pick up the work it left for | |
1175 | us, but we won't see it anymore here... */ | |
1176 | main_running = 0; | |
1177 | local_irq_restore(flags); | |
1178 | } | |
1179 | ||
1180 | ||
1181 | #ifdef REAL_DMA | |
1182 | /* | |
1183 | * Function : void NCR5380_dma_complete (struct Scsi_Host *instance) | |
1184 | * | |
1185 | * Purpose : Called by interrupt handler when DMA finishes or a phase | |
1186 | * mismatch occurs (which would finish the DMA transfer). | |
1187 | * | |
1188 | * Inputs : instance - this instance of the NCR5380. | |
1189 | * | |
1190 | */ | |
1191 | ||
1192 | static void NCR5380_dma_complete( struct Scsi_Host *instance ) | |
1193 | { | |
1194 | SETUP_HOSTDATA(instance); | |
1195 | int transfered, saved_data = 0, overrun = 0, cnt, toPIO; | |
1196 | unsigned char **data, p; | |
1197 | volatile int *count; | |
1198 | ||
1199 | if (!hostdata->connected) { | |
1200 | printk(KERN_WARNING "scsi%d: received end of DMA interrupt with " | |
1201 | "no connected cmd\n", HOSTNO); | |
1202 | return; | |
1203 | } | |
1204 | ||
1205 | if (atari_read_overruns) { | |
1206 | p = hostdata->connected->SCp.phase; | |
1207 | if (p & SR_IO) { | |
1208 | udelay(10); | |
1209 | if ((((NCR5380_read(BUS_AND_STATUS_REG)) & | |
1210 | (BASR_PHASE_MATCH|BASR_ACK)) == | |
1211 | (BASR_PHASE_MATCH|BASR_ACK))) { | |
1212 | saved_data = NCR5380_read(INPUT_DATA_REG); | |
1213 | overrun = 1; | |
1214 | DMA_PRINTK("scsi%d: read overrun handled\n", HOSTNO); | |
1215 | } | |
1216 | } | |
1217 | } | |
1218 | ||
1219 | DMA_PRINTK("scsi%d: real DMA transfer complete, basr 0x%X, sr 0x%X\n", | |
1220 | HOSTNO, NCR5380_read(BUS_AND_STATUS_REG), | |
1221 | NCR5380_read(STATUS_REG)); | |
1222 | ||
1223 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1224 | NCR5380_write(MODE_REG, MR_BASE); | |
1225 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1226 | ||
1227 | transfered = hostdata->dma_len - NCR5380_dma_residual(instance); | |
1228 | hostdata->dma_len = 0; | |
1229 | ||
1230 | data = (unsigned char **) &(hostdata->connected->SCp.ptr); | |
1231 | count = &(hostdata->connected->SCp.this_residual); | |
1232 | *data += transfered; | |
1233 | *count -= transfered; | |
1234 | ||
1235 | if (atari_read_overruns) { | |
1236 | if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) { | |
1237 | cnt = toPIO = atari_read_overruns; | |
1238 | if (overrun) { | |
1239 | DMA_PRINTK("Got an input overrun, using saved byte\n"); | |
1240 | *(*data)++ = saved_data; | |
1241 | (*count)--; | |
1242 | cnt--; | |
1243 | toPIO--; | |
1244 | } | |
1245 | DMA_PRINTK("Doing %d-byte PIO to 0x%08lx\n", cnt, (long)*data); | |
1246 | NCR5380_transfer_pio(instance, &p, &cnt, data); | |
1247 | *count -= toPIO - cnt; | |
1248 | } | |
1249 | } | |
1250 | } | |
1251 | #endif /* REAL_DMA */ | |
1252 | ||
1253 | ||
1254 | /* | |
1255 | * Function : void NCR5380_intr (int irq) | |
1256 | * | |
1257 | * Purpose : handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses | |
1258 | * from the disconnected queue, and restarting NCR5380_main() | |
1259 | * as required. | |
1260 | * | |
1261 | * Inputs : int irq, irq that caused this interrupt. | |
1262 | * | |
1263 | */ | |
1264 | ||
1265 | static irqreturn_t NCR5380_intr (int irq, void *dev_id, struct pt_regs *regs) | |
1266 | { | |
1267 | struct Scsi_Host *instance = first_instance; | |
1268 | int done = 1, handled = 0; | |
1269 | unsigned char basr; | |
1270 | ||
1271 | INT_PRINTK("scsi%d: NCR5380 irq triggered\n", HOSTNO); | |
1272 | ||
1273 | /* Look for pending interrupts */ | |
1274 | basr = NCR5380_read(BUS_AND_STATUS_REG); | |
1275 | INT_PRINTK("scsi%d: BASR=%02x\n", HOSTNO, basr); | |
1276 | /* dispatch to appropriate routine if found and done=0 */ | |
1277 | if (basr & BASR_IRQ) { | |
1278 | NCR_PRINT(NDEBUG_INTR); | |
1279 | if ((NCR5380_read(STATUS_REG) & (SR_SEL|SR_IO)) == (SR_SEL|SR_IO)) { | |
1280 | done = 0; | |
1281 | ENABLE_IRQ(); | |
1282 | INT_PRINTK("scsi%d: SEL interrupt\n", HOSTNO); | |
1283 | NCR5380_reselect(instance); | |
1284 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1285 | } | |
1286 | else if (basr & BASR_PARITY_ERROR) { | |
1287 | INT_PRINTK("scsi%d: PARITY interrupt\n", HOSTNO); | |
1288 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1289 | } | |
1290 | else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) { | |
1291 | INT_PRINTK("scsi%d: RESET interrupt\n", HOSTNO); | |
1292 | (void)NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1293 | } | |
1294 | else { | |
1295 | /* | |
1296 | * The rest of the interrupt conditions can occur only during a | |
1297 | * DMA transfer | |
1298 | */ | |
1299 | ||
1300 | #if defined(REAL_DMA) | |
1301 | /* | |
1302 | * We should only get PHASE MISMATCH and EOP interrupts if we have | |
1303 | * DMA enabled, so do a sanity check based on the current setting | |
1304 | * of the MODE register. | |
1305 | */ | |
1306 | ||
1307 | if ((NCR5380_read(MODE_REG) & MR_DMA_MODE) && | |
1308 | ((basr & BASR_END_DMA_TRANSFER) || | |
1309 | !(basr & BASR_PHASE_MATCH))) { | |
1310 | ||
1311 | INT_PRINTK("scsi%d: PHASE MISM or EOP interrupt\n", HOSTNO); | |
1312 | NCR5380_dma_complete( instance ); | |
1313 | done = 0; | |
1314 | ENABLE_IRQ(); | |
1315 | } else | |
1316 | #endif /* REAL_DMA */ | |
1317 | { | |
1318 | /* MS: Ignore unknown phase mismatch interrupts (caused by EOP interrupt) */ | |
1319 | if (basr & BASR_PHASE_MATCH) | |
1320 | printk(KERN_NOTICE "scsi%d: unknown interrupt, " | |
1321 | "BASR 0x%x, MR 0x%x, SR 0x%x\n", | |
1322 | HOSTNO, basr, NCR5380_read(MODE_REG), | |
1323 | NCR5380_read(STATUS_REG)); | |
1324 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1325 | } | |
1326 | } /* if !(SELECTION || PARITY) */ | |
1327 | handled = 1; | |
1328 | } /* BASR & IRQ */ | |
1329 | else { | |
1330 | printk(KERN_NOTICE "scsi%d: interrupt without IRQ bit set in BASR, " | |
1331 | "BASR 0x%X, MR 0x%X, SR 0x%x\n", HOSTNO, basr, | |
1332 | NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG)); | |
1333 | (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG); | |
1334 | } | |
1335 | ||
1336 | if (!done) { | |
1337 | INT_PRINTK("scsi%d: in int routine, calling main\n", HOSTNO); | |
1338 | /* Put a call to NCR5380_main() on the queue... */ | |
1339 | queue_main(); | |
1340 | } | |
1341 | return IRQ_RETVAL(handled); | |
1342 | } | |
1343 | ||
1344 | #ifdef NCR5380_STATS | |
1345 | static void collect_stats(struct NCR5380_hostdata* hostdata, Scsi_Cmnd* cmd) | |
1346 | { | |
1347 | # ifdef NCR5380_STAT_LIMIT | |
1348 | if (cmd->request_bufflen > NCR5380_STAT_LIMIT) | |
1349 | # endif | |
1350 | switch (cmd->cmnd[0]) | |
1351 | { | |
1352 | case WRITE: | |
1353 | case WRITE_6: | |
1354 | case WRITE_10: | |
1355 | hostdata->time_write[cmd->device->id] += (jiffies - hostdata->timebase); | |
1356 | /*hostdata->bytes_write[cmd->device->id] += cmd->request_bufflen;*/ | |
1357 | hostdata->pendingw--; | |
1358 | break; | |
1359 | case READ: | |
1360 | case READ_6: | |
1361 | case READ_10: | |
1362 | hostdata->time_read[cmd->device->id] += (jiffies - hostdata->timebase); | |
1363 | /*hostdata->bytes_read[cmd->device->id] += cmd->request_bufflen;*/ | |
1364 | hostdata->pendingr--; | |
1365 | break; | |
1366 | } | |
1367 | } | |
1368 | #endif | |
1369 | ||
1370 | /* | |
1371 | * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, | |
1372 | * int tag); | |
1373 | * | |
1374 | * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command, | |
1375 | * including ARBITRATION, SELECTION, and initial message out for | |
1376 | * IDENTIFY and queue messages. | |
1377 | * | |
1378 | * Inputs : instance - instantiation of the 5380 driver on which this | |
1379 | * target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for | |
1380 | * new tag, TAG_NONE for untagged queueing, otherwise set to the tag for | |
1381 | * the command that is presently connected. | |
1382 | * | |
1383 | * Returns : -1 if selection could not execute for some reason, | |
1384 | * 0 if selection succeeded or failed because the target | |
1385 | * did not respond. | |
1386 | * | |
1387 | * Side effects : | |
1388 | * If bus busy, arbitration failed, etc, NCR5380_select() will exit | |
1389 | * with registers as they should have been on entry - ie | |
1390 | * SELECT_ENABLE will be set appropriately, the NCR5380 | |
1391 | * will cease to drive any SCSI bus signals. | |
1392 | * | |
1393 | * If successful : I_T_L or I_T_L_Q nexus will be established, | |
1394 | * instance->connected will be set to cmd. | |
1395 | * SELECT interrupt will be disabled. | |
1396 | * | |
1397 | * If failed (no target) : cmd->scsi_done() will be called, and the | |
1398 | * cmd->result host byte set to DID_BAD_TARGET. | |
1399 | */ | |
1400 | ||
1401 | static int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag) | |
1402 | { | |
1403 | SETUP_HOSTDATA(instance); | |
1404 | unsigned char tmp[3], phase; | |
1405 | unsigned char *data; | |
1406 | int len; | |
1407 | unsigned long timeout; | |
1408 | unsigned long flags; | |
1409 | ||
1410 | hostdata->restart_select = 0; | |
1411 | NCR_PRINT(NDEBUG_ARBITRATION); | |
1412 | ARB_PRINTK("scsi%d: starting arbitration, id = %d\n", HOSTNO, | |
1413 | instance->this_id); | |
1414 | ||
1415 | /* | |
1416 | * Set the phase bits to 0, otherwise the NCR5380 won't drive the | |
1417 | * data bus during SELECTION. | |
1418 | */ | |
1419 | ||
1420 | local_irq_save(flags); | |
1421 | if (hostdata->connected) { | |
1422 | local_irq_restore(flags); | |
1423 | return -1; | |
1424 | } | |
1425 | NCR5380_write(TARGET_COMMAND_REG, 0); | |
1426 | ||
1427 | ||
1428 | /* | |
1429 | * Start arbitration. | |
1430 | */ | |
1431 | ||
1432 | NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask); | |
1433 | NCR5380_write(MODE_REG, MR_ARBITRATE); | |
1434 | ||
1435 | local_irq_restore(flags); | |
1436 | ||
1437 | /* Wait for arbitration logic to complete */ | |
1438 | #if NCR_TIMEOUT | |
1439 | { | |
1440 | unsigned long timeout = jiffies + 2*NCR_TIMEOUT; | |
1441 | ||
1442 | while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) | |
1443 | && time_before(jiffies, timeout) && !hostdata->connected) | |
1444 | ; | |
1445 | if (time_after_eq(jiffies, timeout)) | |
1446 | { | |
1447 | printk("scsi : arbitration timeout at %d\n", __LINE__); | |
1448 | NCR5380_write(MODE_REG, MR_BASE); | |
1449 | NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask); | |
1450 | return -1; | |
1451 | } | |
1452 | } | |
1453 | #else /* NCR_TIMEOUT */ | |
1454 | while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) | |
1455 | && !hostdata->connected); | |
1456 | #endif | |
1457 | ||
1458 | ARB_PRINTK("scsi%d: arbitration complete\n", HOSTNO); | |
1459 | ||
1460 | if (hostdata->connected) { | |
1461 | NCR5380_write(MODE_REG, MR_BASE); | |
1462 | return -1; | |
1463 | } | |
1464 | /* | |
1465 | * The arbitration delay is 2.2us, but this is a minimum and there is | |
1466 | * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate | |
1467 | * the integral nature of udelay(). | |
1468 | * | |
1469 | */ | |
1470 | ||
1471 | udelay(3); | |
1472 | ||
1473 | /* Check for lost arbitration */ | |
1474 | if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1475 | (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) || | |
1476 | (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1477 | hostdata->connected) { | |
1478 | NCR5380_write(MODE_REG, MR_BASE); | |
1479 | ARB_PRINTK("scsi%d: lost arbitration, deasserting MR_ARBITRATE\n", | |
1480 | HOSTNO); | |
1481 | return -1; | |
1482 | } | |
1483 | ||
1484 | /* after/during arbitration, BSY should be asserted. | |
1485 | IBM DPES-31080 Version S31Q works now */ | |
1486 | /* Tnx to Thomas_Roesch@m2.maus.de for finding this! (Roman) */ | |
1487 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_SEL | | |
1488 | ICR_ASSERT_BSY ) ; | |
1489 | ||
1490 | if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || | |
1491 | hostdata->connected) { | |
1492 | NCR5380_write(MODE_REG, MR_BASE); | |
1493 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1494 | ARB_PRINTK("scsi%d: lost arbitration, deasserting ICR_ASSERT_SEL\n", | |
1495 | HOSTNO); | |
1496 | return -1; | |
1497 | } | |
1498 | ||
1499 | /* | |
1500 | * Again, bus clear + bus settle time is 1.2us, however, this is | |
1501 | * a minimum so we'll udelay ceil(1.2) | |
1502 | */ | |
1503 | ||
1504 | #ifdef CONFIG_ATARI_SCSI_TOSHIBA_DELAY | |
1505 | /* ++roman: But some targets (see above :-) seem to need a bit more... */ | |
1506 | udelay(15); | |
1507 | #else | |
1508 | udelay(2); | |
1509 | #endif | |
1510 | ||
1511 | if (hostdata->connected) { | |
1512 | NCR5380_write(MODE_REG, MR_BASE); | |
1513 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1514 | return -1; | |
1515 | } | |
1516 | ||
1517 | ARB_PRINTK("scsi%d: won arbitration\n", HOSTNO); | |
1518 | ||
1519 | /* | |
1520 | * Now that we have won arbitration, start Selection process, asserting | |
1521 | * the host and target ID's on the SCSI bus. | |
1522 | */ | |
1523 | ||
1524 | NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << cmd->device->id))); | |
1525 | ||
1526 | /* | |
1527 | * Raise ATN while SEL is true before BSY goes false from arbitration, | |
1528 | * since this is the only way to guarantee that we'll get a MESSAGE OUT | |
1529 | * phase immediately after selection. | |
1530 | */ | |
1531 | ||
1532 | NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_BSY | | |
1533 | ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL )); | |
1534 | NCR5380_write(MODE_REG, MR_BASE); | |
1535 | ||
1536 | /* | |
1537 | * Reselect interrupts must be turned off prior to the dropping of BSY, | |
1538 | * otherwise we will trigger an interrupt. | |
1539 | */ | |
1540 | ||
1541 | if (hostdata->connected) { | |
1542 | NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); | |
1543 | return -1; | |
1544 | } | |
1545 | ||
1546 | NCR5380_write(SELECT_ENABLE_REG, 0); | |
1547 | ||
1548 | /* | |
1549 | * The initiator shall then wait at least two deskew delays and release | |
1550 | * the BSY signal. | |
1551 | */ | |
1552 | udelay(1); /* wingel -- wait two bus deskew delay >2*45ns */ | |
1553 | ||
1554 | /* Reset BSY */ | |
1555 | NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_DATA | | |
1556 | ICR_ASSERT_ATN | ICR_ASSERT_SEL)); | |
1557 | ||
1558 | /* | |
1559 | * Something weird happens when we cease to drive BSY - looks | |
1560 | * like the board/chip is letting us do another read before the | |
1561 | * appropriate propagation delay has expired, and we're confusing | |
1562 | * a BSY signal from ourselves as the target's response to SELECTION. | |
1563 | * | |
1564 | * A small delay (the 'C++' frontend breaks the pipeline with an | |
1565 | * unnecessary jump, making it work on my 386-33/Trantor T128, the | |
1566 | * tighter 'C' code breaks and requires this) solves the problem - | |
1567 | * the 1 us delay is arbitrary, and only used because this delay will | |
1568 | * be the same on other platforms and since it works here, it should | |
1569 | * work there. | |
1570 | * | |
1571 | * wingel suggests that this could be due to failing to wait | |
1572 | * one deskew delay. | |
1573 | */ | |
1574 | ||
1575 | udelay(1); | |
1576 | ||
1577 | SEL_PRINTK("scsi%d: selecting target %d\n", HOSTNO, cmd->device->id); | |
1578 | ||
1579 | /* | |
1580 | * The SCSI specification calls for a 250 ms timeout for the actual | |
1581 | * selection. | |
1582 | */ | |
1583 | ||
1584 | timeout = jiffies + 25; | |
1585 | ||
1586 | /* | |
1587 | * XXX very interesting - we're seeing a bounce where the BSY we | |
1588 | * asserted is being reflected / still asserted (propagation delay?) | |
1589 | * and it's detecting as true. Sigh. | |
1590 | */ | |
1591 | ||
1592 | #if 0 | |
1593 | /* ++roman: If a target conformed to the SCSI standard, it wouldn't assert | |
1594 | * IO while SEL is true. But again, there are some disks out the in the | |
1595 | * world that do that nevertheless. (Somebody claimed that this announces | |
1596 | * reselection capability of the target.) So we better skip that test and | |
1597 |