1// SPDX-License-Identifier: GPL-2.0
2/*
3 * zfcp device driver
4 *
5 * Setup and helper functions to access QDIO.
6 *
7 * Copyright IBM Corp. 2002, 2020
8 */
9
10#define KMSG_COMPONENT "zfcp"
11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13#include <linux/slab.h>
14#include <linux/module.h>
15#include "zfcp_ext.h"
16#include "zfcp_qdio.h"
17
18static bool enable_multibuffer = true;
19module_param_named(datarouter, enable_multibuffer, bool, 0400);
20MODULE_PARM_DESC(datarouter, "Enable hardware data router support (default on)");
21
22static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *dbftag,
23				    unsigned int qdio_err)
24{
25	struct zfcp_adapter *adapter = qdio->adapter;
26
27	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");
28
29	if (qdio_err & QDIO_ERROR_SLSB_STATE) {
30		zfcp_qdio_siosl(adapter);
31		zfcp_erp_adapter_shutdown(adapter, 0, dbftag);
32		return;
33	}
34	zfcp_erp_adapter_reopen(adapter,
35				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
36				ZFCP_STATUS_COMMON_ERP_FAILED, dbftag);
37}
38
39static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
40{
41	int i, sbal_idx;
42
43	for (i = first; i < first + cnt; i++) {
44		sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
45		memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
46	}
47}
48
49/* this needs to be called prior to updating the queue fill level */
50static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)
51{
52	unsigned long long now, span;
53	int used;
54
55	now = get_tod_clock_monotonic();
56	span = (now - qdio->req_q_time) >> 12;
57	used = QDIO_MAX_BUFFERS_PER_Q - atomic_read(&qdio->req_q_free);
58	qdio->req_q_util += used * span;
59	qdio->req_q_time = now;
60}
61
62static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
63			      int queue_no, int idx, int count,
64			      unsigned long parm)
65{
66	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
67
68	if (unlikely(qdio_err)) {
69		zfcp_qdio_handler_error(qdio, "qdireq1", qdio_err);
70		return;
71	}
72
73	/* cleanup all SBALs being program-owned now */
74	zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
75
76	spin_lock_irq(&qdio->stat_lock);
77	zfcp_qdio_account(qdio);
78	spin_unlock_irq(&qdio->stat_lock);
79	atomic_add(count, &qdio->req_q_free);
80	wake_up(&qdio->req_q_wq);
81}
82
83static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
84			       int queue_no, int idx, int count,
85			       unsigned long parm)
86{
87	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
88	struct zfcp_adapter *adapter = qdio->adapter;
89	int sbal_no, sbal_idx;
90
91	if (unlikely(qdio_err)) {
92		if (zfcp_adapter_multi_buffer_active(adapter)) {
93			void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
94			struct qdio_buffer_element *sbale;
95			u64 req_id;
96			u8 scount;
97
98			memset(pl, 0,
99			       ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
100			sbale = qdio->res_q[idx]->element;
101			req_id = sbale->addr;
102			scount = min(sbale->scount + 1,
103				     ZFCP_QDIO_MAX_SBALS_PER_REQ + 1);
104				     /* incl. signaling SBAL */
105
106			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
107				sbal_idx = (idx + sbal_no) %
108					QDIO_MAX_BUFFERS_PER_Q;
109				pl[sbal_no] = qdio->res_q[sbal_idx];
110			}
111			zfcp_dbf_hba_def_err(adapter, req_id, scount, pl);
112		}
113		zfcp_qdio_handler_error(qdio, "qdires1", qdio_err);
114		return;
115	}
116
117	/*
118	 * go through all SBALs from input queue currently
119	 * returned by QDIO layer
120	 */
121	for (sbal_no = 0; sbal_no < count; sbal_no++) {
122		sbal_idx = (idx + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
123		/* go through all SBALEs of SBAL */
124		zfcp_fsf_reqid_check(qdio, sbal_idx);
125	}
126
127	/*
128	 * put SBALs back to response queue
129	 */
130	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, idx, count))
131		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdires2");
132}
133
134static struct qdio_buffer_element *
135zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
136{
137	struct qdio_buffer_element *sbale;
138
139	/* set last entry flag in current SBALE of current SBAL */
140	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
141	sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;
142
143	/* don't exceed last allowed SBAL */
144	if (q_req->sbal_last == q_req->sbal_limit)
145		return NULL;
146
147	/* set chaining flag in first SBALE of current SBAL */
148	sbale = zfcp_qdio_sbale_req(qdio, q_req);
149	sbale->sflags |= SBAL_SFLAGS0_MORE_SBALS;
150
151	/* calculate index of next SBAL */
152	q_req->sbal_last++;
153	q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
154
155	/* keep this requests number of SBALs up-to-date */
156	q_req->sbal_number++;
157	BUG_ON(q_req->sbal_number > ZFCP_QDIO_MAX_SBALS_PER_REQ);
158
159	/* start at first SBALE of new SBAL */
160	q_req->sbale_curr = 0;
161
162	/* set storage-block type for new SBAL */
163	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
164	sbale->sflags |= q_req->sbtype;
165
166	return sbale;
167}
168
169static struct qdio_buffer_element *
170zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
171{
172	if (q_req->sbale_curr == qdio->max_sbale_per_sbal - 1)
173		return zfcp_qdio_sbal_chain(qdio, q_req);
174	q_req->sbale_curr++;
175	return zfcp_qdio_sbale_curr(qdio, q_req);
176}
177
178/**
179 * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
180 * @qdio: pointer to struct zfcp_qdio
181 * @q_req: pointer to struct zfcp_qdio_req
182 * @sg: scatter-gather list
183 * Returns: zero or -EINVAL on error
184 */
185int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
186			    struct scatterlist *sg)
187{
188	struct qdio_buffer_element *sbale;
189
190	/* set storage-block type for this request */
191	sbale = zfcp_qdio_sbale_req(qdio, q_req);
192	sbale->sflags |= q_req->sbtype;
193
194	for (; sg; sg = sg_next(sg)) {
195		sbale = zfcp_qdio_sbale_next(qdio, q_req);
196		if (!sbale) {
197			atomic_inc(&qdio->req_q_full);
198			zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
199					     q_req->sbal_number);
200			return -EINVAL;
201		}
202		sbale->addr = sg_phys(sg);
203		sbale->length = sg->length;
204	}
205	return 0;
206}
207
208static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
209{
210	if (atomic_read(&qdio->req_q_free) ||
211	    !(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
212		return 1;
213	return 0;
214}
215
216/**
217 * zfcp_qdio_sbal_get - get free sbal in request queue, wait if necessary
218 * @qdio: pointer to struct zfcp_qdio
219 *
220 * The req_q_lock must be held by the caller of this function, and
221 * this function may only be called from process context; it will
222 * sleep when waiting for a free sbal.
223 *
224 * Returns: 0 on success, -EIO if there is no free sbal after waiting.
225 */
226int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
227{
228	long ret;
229
230	ret = wait_event_interruptible_lock_irq_timeout(qdio->req_q_wq,
231		       zfcp_qdio_sbal_check(qdio), qdio->req_q_lock, 5 * HZ);
232
233	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
234		return -EIO;
235
236	if (ret > 0)
237		return 0;
238
239	if (!ret) {
240		atomic_inc(&qdio->req_q_full);
241		/* assume hanging outbound queue, try queue recovery */
242		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdsbg_1");
243	}
244
245	return -EIO;
246}
247
248/**
249 * zfcp_qdio_send - send req to QDIO
250 * @qdio: pointer to struct zfcp_qdio
251 * @q_req: pointer to struct zfcp_qdio_req
252 * Returns: 0 on success, error otherwise
253 */
254int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
255{
256	int retval;
257	u8 sbal_number = q_req->sbal_number;
258
259	spin_lock(&qdio->stat_lock);
260	zfcp_qdio_account(qdio);
261	spin_unlock(&qdio->stat_lock);
262
263	atomic_sub(sbal_number, &qdio->req_q_free);
264
265	retval = do_QDIO(qdio->adapter->ccw_device, QDIO_FLAG_SYNC_OUTPUT, 0,
266			 q_req->sbal_first, sbal_number);
267
268	if (unlikely(retval)) {
269		/* Failed to submit the IO, roll back our modifications. */
270		atomic_add(sbal_number, &qdio->req_q_free);
271		zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
272				     sbal_number);
273		return retval;
274	}
275
276	/* account for transferred buffers */
277	qdio->req_q_idx += sbal_number;
278	qdio->req_q_idx %= QDIO_MAX_BUFFERS_PER_Q;
279
280	return 0;
281}
282
283/**
284 * zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
285 * @qdio: pointer to struct zfcp_qdio
286 * Returns: -ENOMEM on memory allocation error or return value from
287 *          qdio_allocate
288 */
289static int zfcp_qdio_allocate(struct zfcp_qdio *qdio)
290{
291	int ret;
292
293	ret = qdio_alloc_buffers(qdio->req_q, QDIO_MAX_BUFFERS_PER_Q);
294	if (ret)
295		return -ENOMEM;
296
297	ret = qdio_alloc_buffers(qdio->res_q, QDIO_MAX_BUFFERS_PER_Q);
298	if (ret)
299		goto free_req_q;
300
301	init_waitqueue_head(&qdio->req_q_wq);
302
303	ret = qdio_allocate(qdio->adapter->ccw_device, 1, 1);
304	if (ret)
305		goto free_res_q;
306
307	return 0;
308
309free_res_q:
310	qdio_free_buffers(qdio->res_q, QDIO_MAX_BUFFERS_PER_Q);
311free_req_q:
312	qdio_free_buffers(qdio->req_q, QDIO_MAX_BUFFERS_PER_Q);
313	return ret;
314}
315
316/**
317 * zfcp_close_qdio - close qdio queues for an adapter
318 * @qdio: pointer to structure zfcp_qdio
319 */
320void zfcp_qdio_close(struct zfcp_qdio *qdio)
321{
322	struct zfcp_adapter *adapter = qdio->adapter;
323	int idx, count;
324
325	if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
326		return;
327
328	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
329	spin_lock_irq(&qdio->req_q_lock);
330	atomic_andnot(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
331	spin_unlock_irq(&qdio->req_q_lock);
332
333	wake_up(&qdio->req_q_wq);
334
335	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
336
337	/* cleanup used outbound sbals */
338	count = atomic_read(&qdio->req_q_free);
339	if (count < QDIO_MAX_BUFFERS_PER_Q) {
340		idx = (qdio->req_q_idx + count) % QDIO_MAX_BUFFERS_PER_Q;
341		count = QDIO_MAX_BUFFERS_PER_Q - count;
342		zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
343	}
344	qdio->req_q_idx = 0;
345	atomic_set(&qdio->req_q_free, 0);
346}
347
348void zfcp_qdio_shost_update(struct zfcp_adapter *const adapter,
349			    const struct zfcp_qdio *const qdio)
350{
351	struct Scsi_Host *const shost = adapter->scsi_host;
352
353	if (shost == NULL)
354		return;
355
356	shost->sg_tablesize = qdio->max_sbale_per_req;
357	shost->max_sectors = qdio->max_sbale_per_req * 8;
358}
359
360/**
361 * zfcp_qdio_open - prepare and initialize response queue
362 * @qdio: pointer to struct zfcp_qdio
363 * Returns: 0 on success, otherwise -EIO
364 */
365int zfcp_qdio_open(struct zfcp_qdio *qdio)
366{
367	struct qdio_buffer **input_sbals[1] = {qdio->res_q};
368	struct qdio_buffer **output_sbals[1] = {qdio->req_q};
369	struct qdio_buffer_element *sbale;
370	struct qdio_initialize init_data = {0};
371	struct zfcp_adapter *adapter = qdio->adapter;
372	struct ccw_device *cdev = adapter->ccw_device;
373	struct qdio_ssqd_desc ssqd;
374	int cc;
375
376	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
377		return -EIO;
378
379	atomic_andnot(ZFCP_STATUS_ADAPTER_SIOSL_ISSUED,
380			  &qdio->adapter->status);
381
382	init_data.q_format = QDIO_ZFCP_QFMT;
383	init_data.qib_rflags = QIB_RFLAGS_ENABLE_DATA_DIV;
384	if (enable_multibuffer)
385		init_data.qdr_ac |= QDR_AC_MULTI_BUFFER_ENABLE;
386	init_data.no_input_qs = 1;
387	init_data.no_output_qs = 1;
388	init_data.input_handler = zfcp_qdio_int_resp;
389	init_data.output_handler = zfcp_qdio_int_req;
390	init_data.int_parm = (unsigned long) qdio;
391	init_data.input_sbal_addr_array = input_sbals;
392	init_data.output_sbal_addr_array = output_sbals;
393	init_data.scan_threshold =
394		QDIO_MAX_BUFFERS_PER_Q - ZFCP_QDIO_MAX_SBALS_PER_REQ * 2;
395
396	if (qdio_establish(cdev, &init_data))
397		goto failed_establish;
398
399	if (qdio_get_ssqd_desc(cdev, &ssqd))
400		goto failed_qdio;
401
402	if (ssqd.qdioac2 & CHSC_AC2_DATA_DIV_ENABLED)
403		atomic_or(ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED,
404				&qdio->adapter->status);
405
406	if (ssqd.qdioac2 & CHSC_AC2_MULTI_BUFFER_ENABLED) {
407		atomic_or(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
408		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER;
409	} else {
410		atomic_andnot(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
411		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER - 1;
412	}
413
414	qdio->max_sbale_per_req =
415		ZFCP_QDIO_MAX_SBALS_PER_REQ * qdio->max_sbale_per_sbal
416		- 2;
417	if (qdio_activate(cdev))
418		goto failed_qdio;
419
420	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
421		sbale = &(qdio->res_q[cc]->element[0]);
422		sbale->length = 0;
423		sbale->eflags = SBAL_EFLAGS_LAST_ENTRY;
424		sbale->sflags = 0;
425		sbale->addr = 0;
426	}
427
428	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0, QDIO_MAX_BUFFERS_PER_Q))
429		goto failed_qdio;
430
431	/* set index of first available SBALS / number of available SBALS */
432	qdio->req_q_idx = 0;
433	atomic_set(&qdio->req_q_free, QDIO_MAX_BUFFERS_PER_Q);
434	atomic_or(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
435
436	zfcp_qdio_shost_update(adapter, qdio);
437
438	return 0;
439
440failed_qdio:
441	qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
442failed_establish:
443	dev_err(&cdev->dev,
444		"Setting up the QDIO connection to the FCP adapter failed\n");
445	return -EIO;
446}
447
448void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
449{
450	if (!qdio)
451		return;
452
453	if (qdio->adapter->ccw_device)
454		qdio_free(qdio->adapter->ccw_device);
455
456	qdio_free_buffers(qdio->req_q, QDIO_MAX_BUFFERS_PER_Q);
457	qdio_free_buffers(qdio->res_q, QDIO_MAX_BUFFERS_PER_Q);
458	kfree(qdio);
459}
460
461int zfcp_qdio_setup(struct zfcp_adapter *adapter)
462{
463	struct zfcp_qdio *qdio;
464
465	qdio = kzalloc(sizeof(struct zfcp_qdio), GFP_KERNEL);
466	if (!qdio)
467		return -ENOMEM;
468
469	qdio->adapter = adapter;
470
471	if (zfcp_qdio_allocate(qdio)) {
472		kfree(qdio);
473		return -ENOMEM;
474	}
475
476	spin_lock_init(&qdio->req_q_lock);
477	spin_lock_init(&qdio->stat_lock);
478
479	adapter->qdio = qdio;
480	return 0;
481}
482
483/**
484 * zfcp_qdio_siosl - Trigger logging in FCP channel
485 * @adapter: The zfcp_adapter where to trigger logging
486 *
487 * Call the cio siosl function to trigger hardware logging.  This
488 * wrapper function sets a flag to ensure hardware logging is only
489 * triggered once before going through qdio shutdown.
490 *
491 * The triggers are always run from qdio tasklet context, so no
492 * additional synchronization is necessary.
493 */
494void zfcp_qdio_siosl(struct zfcp_adapter *adapter)
495{
496	int rc;
497
498	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_SIOSL_ISSUED)
499		return;
500
501	rc = ccw_device_siosl(adapter->ccw_device);
502	if (!rc)
503		atomic_or(ZFCP_STATUS_ADAPTER_SIOSL_ISSUED,
504				&adapter->status);
505}
506