Merge branch 'ext3-latency-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6] / drivers / s390 / scsi / zfcp_qdio.c
1 /*
2  * zfcp device driver
3  *
4  * Setup and helper functions to access QDIO.
5  *
6  * Copyright IBM Corporation 2002, 2008
7  */
8
9 #define KMSG_COMPONENT "zfcp"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include "zfcp_ext.h"
13
14 #define QBUFF_PER_PAGE          (PAGE_SIZE / sizeof(struct qdio_buffer))
15
16 static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
17 {
18         int pos;
19
20         for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
21                 sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
22                 if (!sbal[pos])
23                         return -ENOMEM;
24         }
25         for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
26                 if (pos % QBUFF_PER_PAGE)
27                         sbal[pos] = sbal[pos - 1] + 1;
28         return 0;
29 }
30
31 static struct qdio_buffer_element *
32 zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
33 {
34         return &q->sbal[sbal_idx]->element[sbale_idx];
35 }
36
37 /**
38  * zfcp_qdio_free - free memory used by request- and resposne queue
39  * @adapter: pointer to the zfcp_adapter structure
40  */
41 void zfcp_qdio_free(struct zfcp_adapter *adapter)
42 {
43         struct qdio_buffer **sbal_req, **sbal_resp;
44         int p;
45
46         if (adapter->ccw_device)
47                 qdio_free(adapter->ccw_device);
48
49         sbal_req = adapter->req_q.sbal;
50         sbal_resp = adapter->resp_q.sbal;
51
52         for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
53                 free_page((unsigned long) sbal_req[p]);
54                 free_page((unsigned long) sbal_resp[p]);
55         }
56 }
57
58 static void zfcp_qdio_handler_error(struct zfcp_adapter *adapter, char *id)
59 {
60         dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");
61
62         zfcp_erp_adapter_reopen(adapter,
63                                 ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
64                                 ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
65 }
66
67 static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
68 {
69         int i, sbal_idx;
70
71         for (i = first; i < first + cnt; i++) {
72                 sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
73                 memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
74         }
75 }
76
77 /* this needs to be called prior to updating the queue fill level */
78 static void zfcp_qdio_account(struct zfcp_adapter *adapter)
79 {
80         ktime_t now;
81         s64 span;
82         int free, used;
83
84         spin_lock(&adapter->qdio_stat_lock);
85         now = ktime_get();
86         span = ktime_us_delta(now, adapter->req_q_time);
87         free = max(0, atomic_read(&adapter->req_q.count));
88         used = QDIO_MAX_BUFFERS_PER_Q - free;
89         adapter->req_q_util += used * span;
90         adapter->req_q_time = now;
91         spin_unlock(&adapter->qdio_stat_lock);
92 }
93
94 static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
95                               int queue_no, int first, int count,
96                               unsigned long parm)
97 {
98         struct zfcp_adapter *adapter = (struct zfcp_adapter *) parm;
99         struct zfcp_qdio_queue *queue = &adapter->req_q;
100
101         if (unlikely(qdio_err)) {
102                 zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
103                 zfcp_qdio_handler_error(adapter, "qdireq1");
104                 return;
105         }
106
107         /* cleanup all SBALs being program-owned now */
108         zfcp_qdio_zero_sbals(queue->sbal, first, count);
109
110         zfcp_qdio_account(adapter);
111         atomic_add(count, &queue->count);
112         wake_up(&adapter->request_wq);
113 }
114
115 static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
116                                   unsigned long req_id, int sbal_idx)
117 {
118         struct zfcp_fsf_req *fsf_req;
119         unsigned long flags;
120
121         spin_lock_irqsave(&adapter->req_list_lock, flags);
122         fsf_req = zfcp_reqlist_find(adapter, req_id);
123
124         if (!fsf_req)
125                 /*
126                  * Unknown request means that we have potentially memory
127                  * corruption and must stop the machine immediatly.
128                  */
129                 panic("error: unknown request id (%lx) on adapter %s.\n",
130                       req_id, dev_name(&adapter->ccw_device->dev));
131
132         zfcp_reqlist_remove(adapter, fsf_req);
133         spin_unlock_irqrestore(&adapter->req_list_lock, flags);
134
135         fsf_req->sbal_response = sbal_idx;
136         fsf_req->qdio_inb_usage = atomic_read(&adapter->resp_q.count);
137         zfcp_fsf_req_complete(fsf_req);
138 }
139
140 static void zfcp_qdio_resp_put_back(struct zfcp_adapter *adapter, int processed)
141 {
142         struct zfcp_qdio_queue *queue = &adapter->resp_q;
143         struct ccw_device *cdev = adapter->ccw_device;
144         u8 count, start = queue->first;
145         unsigned int retval;
146
147         count = atomic_read(&queue->count) + processed;
148
149         retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);
150
151         if (unlikely(retval)) {
152                 atomic_set(&queue->count, count);
153                 /* FIXME: Recover this with an adapter reopen? */
154         } else {
155                 queue->first += count;
156                 queue->first %= QDIO_MAX_BUFFERS_PER_Q;
157                 atomic_set(&queue->count, 0);
158         }
159 }
160
161 static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
162                                int queue_no, int first, int count,
163                                unsigned long parm)
164 {
165         struct zfcp_adapter *adapter = (struct zfcp_adapter *) parm;
166         struct zfcp_qdio_queue *queue = &adapter->resp_q;
167         struct qdio_buffer_element *sbale;
168         int sbal_idx, sbale_idx, sbal_no;
169
170         if (unlikely(qdio_err)) {
171                 zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
172                 zfcp_qdio_handler_error(adapter, "qdires1");
173                 return;
174         }
175
176         /*
177          * go through all SBALs from input queue currently
178          * returned by QDIO layer
179          */
180         for (sbal_no = 0; sbal_no < count; sbal_no++) {
181                 sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
182
183                 /* go through all SBALEs of SBAL */
184                 for (sbale_idx = 0; sbale_idx < QDIO_MAX_ELEMENTS_PER_BUFFER;
185                      sbale_idx++) {
186                         sbale = zfcp_qdio_sbale(queue, sbal_idx, sbale_idx);
187                         zfcp_qdio_reqid_check(adapter,
188                                               (unsigned long) sbale->addr,
189                                               sbal_idx);
190                         if (likely(sbale->flags & SBAL_FLAGS_LAST_ENTRY))
191                                 break;
192                 };
193
194                 if (unlikely(!(sbale->flags & SBAL_FLAGS_LAST_ENTRY)))
195                         dev_warn(&adapter->ccw_device->dev,
196                                  "A QDIO protocol error occurred, "
197                                  "operations continue\n");
198         }
199
200         /*
201          * put range of SBALs back to response queue
202          * (including SBALs which have already been free before)
203          */
204         zfcp_qdio_resp_put_back(adapter, count);
205 }
206
207 /**
208  * zfcp_qdio_sbale_req - return ptr to SBALE of req_q for a struct zfcp_fsf_req
209  * @fsf_req: pointer to struct fsf_req
210  * Returns: pointer to qdio_buffer_element (SBALE) structure
211  */
212 struct qdio_buffer_element *zfcp_qdio_sbale_req(struct zfcp_fsf_req *req)
213 {
214         return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last, 0);
215 }
216
217 /**
218  * zfcp_qdio_sbale_curr - return curr SBALE on req_q for a struct zfcp_fsf_req
219  * @fsf_req: pointer to struct fsf_req
220  * Returns: pointer to qdio_buffer_element (SBALE) structure
221  */
222 struct qdio_buffer_element *zfcp_qdio_sbale_curr(struct zfcp_fsf_req *req)
223 {
224         return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last,
225                                req->sbale_curr);
226 }
227
228 static void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
229 {
230         int count = atomic_read(&fsf_req->adapter->req_q.count);
231         count = min(count, max_sbals);
232         fsf_req->sbal_limit = (fsf_req->sbal_first + count - 1)
233                                         % QDIO_MAX_BUFFERS_PER_Q;
234 }
235
236 static struct qdio_buffer_element *
237 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
238 {
239         struct qdio_buffer_element *sbale;
240
241         /* set last entry flag in current SBALE of current SBAL */
242         sbale = zfcp_qdio_sbale_curr(fsf_req);
243         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
244
245         /* don't exceed last allowed SBAL */
246         if (fsf_req->sbal_last == fsf_req->sbal_limit)
247                 return NULL;
248
249         /* set chaining flag in first SBALE of current SBAL */
250         sbale = zfcp_qdio_sbale_req(fsf_req);
251         sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
252
253         /* calculate index of next SBAL */
254         fsf_req->sbal_last++;
255         fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
256
257         /* keep this requests number of SBALs up-to-date */
258         fsf_req->sbal_number++;
259
260         /* start at first SBALE of new SBAL */
261         fsf_req->sbale_curr = 0;
262
263         /* set storage-block type for new SBAL */
264         sbale = zfcp_qdio_sbale_curr(fsf_req);
265         sbale->flags |= sbtype;
266
267         return sbale;
268 }
269
270 static struct qdio_buffer_element *
271 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
272 {
273         if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
274                 return zfcp_qdio_sbal_chain(fsf_req, sbtype);
275         fsf_req->sbale_curr++;
276         return zfcp_qdio_sbale_curr(fsf_req);
277 }
278
279 static void zfcp_qdio_undo_sbals(struct zfcp_fsf_req *fsf_req)
280 {
281         struct qdio_buffer **sbal = fsf_req->adapter->req_q.sbal;
282         int first = fsf_req->sbal_first;
283         int last = fsf_req->sbal_last;
284         int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
285                 QDIO_MAX_BUFFERS_PER_Q + 1;
286         zfcp_qdio_zero_sbals(sbal, first, count);
287 }
288
289 static int zfcp_qdio_fill_sbals(struct zfcp_fsf_req *fsf_req,
290                                 unsigned int sbtype, void *start_addr,
291                                 unsigned int total_length)
292 {
293         struct qdio_buffer_element *sbale;
294         unsigned long remaining, length;
295         void *addr;
296
297         /* split segment up */
298         for (addr = start_addr, remaining = total_length; remaining > 0;
299              addr += length, remaining -= length) {
300                 sbale = zfcp_qdio_sbale_next(fsf_req, sbtype);
301                 if (!sbale) {
302                         atomic_inc(&fsf_req->adapter->qdio_outb_full);
303                         zfcp_qdio_undo_sbals(fsf_req);
304                         return -EINVAL;
305                 }
306
307                 /* new piece must not exceed next page boundary */
308                 length = min(remaining,
309                              (PAGE_SIZE - ((unsigned long)addr &
310                                            (PAGE_SIZE - 1))));
311                 sbale->addr = addr;
312                 sbale->length = length;
313         }
314         return 0;
315 }
316
317 /**
318  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
319  * @fsf_req: request to be processed
320  * @sbtype: SBALE flags
321  * @sg: scatter-gather list
322  * @max_sbals: upper bound for number of SBALs to be used
323  * Returns: number of bytes, or error (negativ)
324  */
325 int zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
326                             struct scatterlist *sg, int max_sbals)
327 {
328         struct qdio_buffer_element *sbale;
329         int retval, bytes = 0;
330
331         /* figure out last allowed SBAL */
332         zfcp_qdio_sbal_limit(fsf_req, max_sbals);
333
334         /* set storage-block type for this request */
335         sbale = zfcp_qdio_sbale_req(fsf_req);
336         sbale->flags |= sbtype;
337
338         for (; sg; sg = sg_next(sg)) {
339                 retval = zfcp_qdio_fill_sbals(fsf_req, sbtype, sg_virt(sg),
340                                               sg->length);
341                 if (retval < 0)
342                         return retval;
343                 bytes += sg->length;
344         }
345
346         /* assume that no other SBALEs are to follow in the same SBAL */
347         sbale = zfcp_qdio_sbale_curr(fsf_req);
348         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
349
350         return bytes;
351 }
352
353 /**
354  * zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
355  * @fsf_req: pointer to struct zfcp_fsf_req
356  * Returns: 0 on success, error otherwise
357  */
358 int zfcp_qdio_send(struct zfcp_fsf_req *fsf_req)
359 {
360         struct zfcp_adapter *adapter = fsf_req->adapter;
361         struct zfcp_qdio_queue *req_q = &adapter->req_q;
362         int first = fsf_req->sbal_first;
363         int count = fsf_req->sbal_number;
364         int retval;
365         unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;
366
367         zfcp_qdio_account(adapter);
368
369         retval = do_QDIO(adapter->ccw_device, qdio_flags, 0, first, count);
370         if (unlikely(retval)) {
371                 zfcp_qdio_zero_sbals(req_q->sbal, first, count);
372                 return retval;
373         }
374
375         /* account for transferred buffers */
376         atomic_sub(count, &req_q->count);
377         req_q->first += count;
378         req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
379         return 0;
380 }
381
382 /**
383  * zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
384  * @adapter: pointer to struct zfcp_adapter
385  * Returns: -ENOMEM on memory allocation error or return value from
386  *          qdio_allocate
387  */
388 int zfcp_qdio_allocate(struct zfcp_adapter *adapter)
389 {
390         struct qdio_initialize *init_data;
391
392         if (zfcp_qdio_buffers_enqueue(adapter->req_q.sbal) ||
393                    zfcp_qdio_buffers_enqueue(adapter->resp_q.sbal))
394                 return -ENOMEM;
395
396         init_data = &adapter->qdio_init_data;
397
398         init_data->cdev = adapter->ccw_device;
399         init_data->q_format = QDIO_ZFCP_QFMT;
400         memcpy(init_data->adapter_name, dev_name(&adapter->ccw_device->dev), 8);
401         ASCEBC(init_data->adapter_name, 8);
402         init_data->qib_param_field_format = 0;
403         init_data->qib_param_field = NULL;
404         init_data->input_slib_elements = NULL;
405         init_data->output_slib_elements = NULL;
406         init_data->no_input_qs = 1;
407         init_data->no_output_qs = 1;
408         init_data->input_handler = zfcp_qdio_int_resp;
409         init_data->output_handler = zfcp_qdio_int_req;
410         init_data->int_parm = (unsigned long) adapter;
411         init_data->flags = QDIO_INBOUND_0COPY_SBALS |
412                         QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
413         init_data->input_sbal_addr_array =
414                         (void **) (adapter->resp_q.sbal);
415         init_data->output_sbal_addr_array =
416                         (void **) (adapter->req_q.sbal);
417
418         return qdio_allocate(init_data);
419 }
420
421 /**
422  * zfcp_close_qdio - close qdio queues for an adapter
423  */
424 void zfcp_qdio_close(struct zfcp_adapter *adapter)
425 {
426         struct zfcp_qdio_queue *req_q;
427         int first, count;
428
429         if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
430                 return;
431
432         /* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
433         req_q = &adapter->req_q;
434         spin_lock_bh(&adapter->req_q_lock);
435         atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
436         spin_unlock_bh(&adapter->req_q_lock);
437
438         qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
439
440         /* cleanup used outbound sbals */
441         count = atomic_read(&req_q->count);
442         if (count < QDIO_MAX_BUFFERS_PER_Q) {
443                 first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
444                 count = QDIO_MAX_BUFFERS_PER_Q - count;
445                 zfcp_qdio_zero_sbals(req_q->sbal, first, count);
446         }
447         req_q->first = 0;
448         atomic_set(&req_q->count, 0);
449         adapter->resp_q.first = 0;
450         atomic_set(&adapter->resp_q.count, 0);
451 }
452
453 /**
454  * zfcp_qdio_open - prepare and initialize response queue
455  * @adapter: pointer to struct zfcp_adapter
456  * Returns: 0 on success, otherwise -EIO
457  */
458 int zfcp_qdio_open(struct zfcp_adapter *adapter)
459 {
460         struct qdio_buffer_element *sbale;
461         int cc;
462
463         if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
464                 return -EIO;
465
466         if (qdio_establish(&adapter->qdio_init_data))
467                 goto failed_establish;
468
469         if (qdio_activate(adapter->ccw_device))
470                 goto failed_qdio;
471
472         for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
473                 sbale = &(adapter->resp_q.sbal[cc]->element[0]);
474                 sbale->length = 0;
475                 sbale->flags = SBAL_FLAGS_LAST_ENTRY;
476                 sbale->addr = NULL;
477         }
478
479         if (do_QDIO(adapter->ccw_device, QDIO_FLAG_SYNC_INPUT, 0, 0,
480                      QDIO_MAX_BUFFERS_PER_Q))
481                 goto failed_qdio;
482
483         /* set index of first avalable SBALS / number of available SBALS */
484         adapter->req_q.first = 0;
485         atomic_set(&adapter->req_q.count, QDIO_MAX_BUFFERS_PER_Q);
486
487         return 0;
488
489 failed_qdio:
490         qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
491 failed_establish:
492         dev_err(&adapter->ccw_device->dev,
493                 "Setting up the QDIO connection to the FCP adapter failed\n");
494         return -EIO;
495 }