1// SPDX-License-Identifier: GPL-2.0
  2/* Shared Memory Communications Direct over ISM devices (SMC-D)
  3 *
  4 * Functions for ISM device.
  5 *
  6 * Copyright IBM Corp. 2018
  7 */
  8
  9#include <linux/spinlock.h>
 10#include <linux/mutex.h>
 11#include <linux/slab.h>
 12#include <asm/page.h>
 13
 14#include "smc.h"
 15#include "smc_core.h"
 16#include "smc_ism.h"
 17#include "smc_pnet.h"
 18
 19struct smcd_dev_list smcd_dev_list = {
 20	.list = LIST_HEAD_INIT(smcd_dev_list.list),
 21	.mutex = __MUTEX_INITIALIZER(smcd_dev_list.mutex)
 22};
 23
 24/* Test if an ISM communication is possible. */
 25int smc_ism_cantalk(u64 peer_gid, unsigned short vlan_id, struct smcd_dev *smcd)
 26{
 27	return smcd->ops->query_remote_gid(smcd, peer_gid, vlan_id ? 1 : 0,
 28					   vlan_id);
 29}
 30
 31int smc_ism_write(struct smcd_dev *smcd, const struct smc_ism_position *pos,
 32		  void *data, size_t len)
 33{
 34	int rc;
 35
 36	rc = smcd->ops->move_data(smcd, pos->token, pos->index, pos->signal,
 37				  pos->offset, data, len);
 38
 39	return rc < 0 ? rc : 0;
 40}
 41
 42/* Set a connection using this DMBE. */
 43void smc_ism_set_conn(struct smc_connection *conn)
 44{
 45	unsigned long flags;
 46
 47	spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
 48	conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = conn;
 49	spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
 50}
 51
 52/* Unset a connection using this DMBE. */
 53void smc_ism_unset_conn(struct smc_connection *conn)
 54{
 55	unsigned long flags;
 56
 57	if (!conn->rmb_desc)
 58		return;
 59
 60	spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
 61	conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = NULL;
 62	spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
 63}
 64
 65/* Register a VLAN identifier with the ISM device. Use a reference count
 66 * and add a VLAN identifier only when the first DMB using this VLAN is
 67 * registered.
 68 */
 69int smc_ism_get_vlan(struct smcd_dev *smcd, unsigned short vlanid)
 70{
 71	struct smc_ism_vlanid *new_vlan, *vlan;
 72	unsigned long flags;
 73	int rc = 0;
 74
 75	if (!vlanid)			/* No valid vlan id */
 76		return -EINVAL;
 77
 78	/* create new vlan entry, in case we need it */
 79	new_vlan = kzalloc(sizeof(*new_vlan), GFP_KERNEL);
 80	if (!new_vlan)
 81		return -ENOMEM;
 82	new_vlan->vlanid = vlanid;
 83	refcount_set(&new_vlan->refcnt, 1);
 84
 85	/* if there is an existing entry, increase count and return */
 86	spin_lock_irqsave(&smcd->lock, flags);
 87	list_for_each_entry(vlan, &smcd->vlan, list) {
 88		if (vlan->vlanid == vlanid) {
 89			refcount_inc(&vlan->refcnt);
 90			kfree(new_vlan);
 91			goto out;
 92		}
 93	}
 94
 95	/* no existing entry found.
 96	 * add new entry to device; might fail, e.g., if HW limit reached
 97	 */
 98	if (smcd->ops->add_vlan_id(smcd, vlanid)) {
 99		kfree(new_vlan);
100		rc = -EIO;
101		goto out;
102	}
103	list_add_tail(&new_vlan->list, &smcd->vlan);
104out:
105	spin_unlock_irqrestore(&smcd->lock, flags);
106	return rc;
107}
108
109/* Unregister a VLAN identifier with the ISM device. Use a reference count
110 * and remove a VLAN identifier only when the last DMB using this VLAN is
111 * unregistered.
112 */
113int smc_ism_put_vlan(struct smcd_dev *smcd, unsigned short vlanid)
114{
115	struct smc_ism_vlanid *vlan;
116	unsigned long flags;
117	bool found = false;
118	int rc = 0;
119
120	if (!vlanid)			/* No valid vlan id */
121		return -EINVAL;
122
123	spin_lock_irqsave(&smcd->lock, flags);
124	list_for_each_entry(vlan, &smcd->vlan, list) {
125		if (vlan->vlanid == vlanid) {
126			if (!refcount_dec_and_test(&vlan->refcnt))
127				goto out;
128			found = true;
129			break;
130		}
131	}
132	if (!found) {
133		rc = -ENOENT;
134		goto out;		/* VLAN id not in table */
135	}
136
137	/* Found and the last reference just gone */
138	if (smcd->ops->del_vlan_id(smcd, vlanid))
139		rc = -EIO;
140	list_del(&vlan->list);
141	kfree(vlan);
142out:
143	spin_unlock_irqrestore(&smcd->lock, flags);
144	return rc;
145}
146
147int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
148{
149	struct smcd_dmb dmb;
150	int rc = 0;
151
152	if (!dmb_desc->dma_addr)
153		return rc;
154
155	memset(&dmb, 0, sizeof(dmb));
156	dmb.dmb_tok = dmb_desc->token;
157	dmb.sba_idx = dmb_desc->sba_idx;
158	dmb.cpu_addr = dmb_desc->cpu_addr;
159	dmb.dma_addr = dmb_desc->dma_addr;
160	dmb.dmb_len = dmb_desc->len;
161	rc = smcd->ops->unregister_dmb(smcd, &dmb);
162	if (!rc || rc == ISM_ERROR) {
163		dmb_desc->cpu_addr = NULL;
164		dmb_desc->dma_addr = 0;
165	}
166
167	return rc;
168}
169
170int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
171			 struct smc_buf_desc *dmb_desc)
172{
173	struct smcd_dmb dmb;
174	int rc;
175
176	memset(&dmb, 0, sizeof(dmb));
177	dmb.dmb_len = dmb_len;
178	dmb.sba_idx = dmb_desc->sba_idx;
179	dmb.vlan_id = lgr->vlan_id;
180	dmb.rgid = lgr->peer_gid;
181	rc = lgr->smcd->ops->register_dmb(lgr->smcd, &dmb);
182	if (!rc) {
183		dmb_desc->sba_idx = dmb.sba_idx;
184		dmb_desc->token = dmb.dmb_tok;
185		dmb_desc->cpu_addr = dmb.cpu_addr;
186		dmb_desc->dma_addr = dmb.dma_addr;
187		dmb_desc->len = dmb.dmb_len;
188	}
189	return rc;
190}
191
192struct smc_ism_event_work {
193	struct work_struct work;
194	struct smcd_dev *smcd;
195	struct smcd_event event;
196};
197
198#define ISM_EVENT_REQUEST		0x0001
199#define ISM_EVENT_RESPONSE		0x0002
200#define ISM_EVENT_REQUEST_IR		0x00000001
201#define ISM_EVENT_CODE_SHUTDOWN		0x80
202#define ISM_EVENT_CODE_TESTLINK		0x83
203
204union smcd_sw_event_info {
205	u64	info;
206	struct {
207		u8		uid[SMC_LGR_ID_SIZE];
208		unsigned short	vlan_id;
209		u16		code;
210	};
211};
212
213static void smcd_handle_sw_event(struct smc_ism_event_work *wrk)
214{
215	union smcd_sw_event_info ev_info;
216
217	ev_info.info = wrk->event.info;
218	switch (wrk->event.code) {
219	case ISM_EVENT_CODE_SHUTDOWN:	/* Peer shut down DMBs */
220		smc_smcd_terminate(wrk->smcd, wrk->event.tok, ev_info.vlan_id);
221		break;
222	case ISM_EVENT_CODE_TESTLINK:	/* Activity timer */
223		if (ev_info.code == ISM_EVENT_REQUEST) {
224			ev_info.code = ISM_EVENT_RESPONSE;
225			wrk->smcd->ops->signal_event(wrk->smcd,
226						     wrk->event.tok,
227						     ISM_EVENT_REQUEST_IR,
228						     ISM_EVENT_CODE_TESTLINK,
229						     ev_info.info);
230			}
231		break;
232	}
233}
234
235int smc_ism_signal_shutdown(struct smc_link_group *lgr)
236{
237	int rc;
238	union smcd_sw_event_info ev_info;
239
240	if (lgr->peer_shutdown)
241		return 0;
242
243	memcpy(ev_info.uid, lgr->id, SMC_LGR_ID_SIZE);
244	ev_info.vlan_id = lgr->vlan_id;
245	ev_info.code = ISM_EVENT_REQUEST;
246	rc = lgr->smcd->ops->signal_event(lgr->smcd, lgr->peer_gid,
247					  ISM_EVENT_REQUEST_IR,
248					  ISM_EVENT_CODE_SHUTDOWN,
249					  ev_info.info);
250	return rc;
251}
252
253/* worker for SMC-D events */
254static void smc_ism_event_work(struct work_struct *work)
255{
256	struct smc_ism_event_work *wrk =
257		container_of(work, struct smc_ism_event_work, work);
258
259	switch (wrk->event.type) {
260	case ISM_EVENT_GID:	/* GID event, token is peer GID */
261		smc_smcd_terminate(wrk->smcd, wrk->event.tok, VLAN_VID_MASK);
262		break;
263	case ISM_EVENT_DMB:
264		break;
265	case ISM_EVENT_SWR:	/* Software defined event */
266		smcd_handle_sw_event(wrk);
267		break;
268	}
269	kfree(wrk);
270}
271
272static void smcd_release(struct device *dev)
273{
274	struct smcd_dev *smcd = container_of(dev, struct smcd_dev, dev);
275
276	kfree(smcd->conn);
277	kfree(smcd);
278}
279
280struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
281				const struct smcd_ops *ops, int max_dmbs)
282{
283	struct smcd_dev *smcd;
284
285	smcd = kzalloc(sizeof(*smcd), GFP_KERNEL);
286	if (!smcd)
287		return NULL;
288	smcd->conn = kcalloc(max_dmbs, sizeof(struct smc_connection *),
289			     GFP_KERNEL);
290	if (!smcd->conn) {
291		kfree(smcd);
292		return NULL;
293	}
294
295	smcd->dev.parent = parent;
296	smcd->dev.release = smcd_release;
297	device_initialize(&smcd->dev);
298	dev_set_name(&smcd->dev, name);
299	smcd->ops = ops;
300	if (smc_pnetid_by_dev_port(parent, 0, smcd->pnetid))
301		smc_pnetid_by_table_smcd(smcd);
302
303	spin_lock_init(&smcd->lock);
304	spin_lock_init(&smcd->lgr_lock);
305	INIT_LIST_HEAD(&smcd->vlan);
306	INIT_LIST_HEAD(&smcd->lgr_list);
307	init_waitqueue_head(&smcd->lgrs_deleted);
308	smcd->event_wq = alloc_ordered_workqueue("ism_evt_wq-%s)",
309						 WQ_MEM_RECLAIM, name);
310	if (!smcd->event_wq) {
311		kfree(smcd->conn);
312		kfree(smcd);
313		return NULL;
314	}
315	return smcd;
316}
317EXPORT_SYMBOL_GPL(smcd_alloc_dev);
318
319int smcd_register_dev(struct smcd_dev *smcd)
320{
321	mutex_lock(&smcd_dev_list.mutex);
322	list_add_tail(&smcd->list, &smcd_dev_list.list);
323	mutex_unlock(&smcd_dev_list.mutex);
324
325	pr_warn_ratelimited("smc: adding smcd device %s with pnetid %.16s%s\n",
326			    dev_name(&smcd->dev), smcd->pnetid,
327			    smcd->pnetid_by_user ? " (user defined)" : "");
328
329	return device_add(&smcd->dev);
330}
331EXPORT_SYMBOL_GPL(smcd_register_dev);
332
333void smcd_unregister_dev(struct smcd_dev *smcd)
334{
335	pr_warn_ratelimited("smc: removing smcd device %s\n",
336			    dev_name(&smcd->dev));
337	mutex_lock(&smcd_dev_list.mutex);
338	list_del_init(&smcd->list);
339	mutex_unlock(&smcd_dev_list.mutex);
340	smcd->going_away = 1;
341	smc_smcd_terminate_all(smcd);
342	flush_workqueue(smcd->event_wq);
343	destroy_workqueue(smcd->event_wq);
344
345	device_del(&smcd->dev);
346}
347EXPORT_SYMBOL_GPL(smcd_unregister_dev);
348
349void smcd_free_dev(struct smcd_dev *smcd)
350{
351	put_device(&smcd->dev);
352}
353EXPORT_SYMBOL_GPL(smcd_free_dev);
354
355/* SMCD Device event handler. Called from ISM device interrupt handler.
356 * Parameters are smcd device pointer,
357 * - event->type (0 --> DMB, 1 --> GID),
358 * - event->code (event code),
359 * - event->tok (either DMB token when event type 0, or GID when event type 1)
360 * - event->time (time of day)
361 * - event->info (debug info).
362 *
363 * Context:
364 * - Function called in IRQ context from ISM device driver event handler.
365 */
366void smcd_handle_event(struct smcd_dev *smcd, struct smcd_event *event)
367{
368	struct smc_ism_event_work *wrk;
369
370	if (smcd->going_away)
371		return;
372	/* copy event to event work queue, and let it be handled there */
373	wrk = kmalloc(sizeof(*wrk), GFP_ATOMIC);
374	if (!wrk)
375		return;
376	INIT_WORK(&wrk->work, smc_ism_event_work);
377	wrk->smcd = smcd;
378	wrk->event = *event;
379	queue_work(smcd->event_wq, &wrk->work);
380}
381EXPORT_SYMBOL_GPL(smcd_handle_event);
382
383/* SMCD Device interrupt handler. Called from ISM device interrupt handler.
384 * Parameters are smcd device pointer and DMB number. Find the connection and
385 * schedule the tasklet for this connection.
386 *
387 * Context:
388 * - Function called in IRQ context from ISM device driver IRQ handler.
389 */
390void smcd_handle_irq(struct smcd_dev *smcd, unsigned int dmbno)
391{
392	struct smc_connection *conn = NULL;
393	unsigned long flags;
394
395	spin_lock_irqsave(&smcd->lock, flags);
396	conn = smcd->conn[dmbno];
397	if (conn && !conn->killed)
398		tasklet_schedule(&conn->rx_tsklet);
399	spin_unlock_irqrestore(&smcd->lock, flags);
400}
401EXPORT_SYMBOL_GPL(smcd_handle_irq);