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