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
18 struct 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. */
smc_ism_cantalk(u64 peer_gid,unsigned short vlan_id,struct smcd_dev * smcd)24 int 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
smc_ism_write(struct smcd_dev * smcd,const struct smc_ism_position * pos,void * data,size_t len)30 int 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. */
smc_ism_set_conn(struct smc_connection * conn)42 void 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. */
smc_ism_unset_conn(struct smc_connection * conn)52 void 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 */
smc_ism_get_vlan(struct smcd_dev * smcd,unsigned short vlanid)68 int 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);
103 out:
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 */
smc_ism_put_vlan(struct smcd_dev * smcd,unsigned short vlanid)112 int 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);
141 out:
142 spin_unlock_irqrestore(&smcd->lock, flags);
143 return rc;
144 }
145
smc_ism_unregister_dmb(struct smcd_dev * smcd,struct smc_buf_desc * dmb_desc)146 int 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
smc_ism_register_dmb(struct smc_link_group * lgr,int dmb_len,struct smc_buf_desc * dmb_desc)159 int 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
181 struct 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
193 union 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
smcd_handle_sw_event(struct smc_ism_event_work * wrk)202 static 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
smc_ism_signal_shutdown(struct smc_link_group * lgr)224 int 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 */
smc_ism_event_work(struct work_struct * work)240 static 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
smcd_release(struct device * dev)258 static 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
smcd_alloc_dev(struct device * parent,const char * name,const struct smcd_ops * ops,int max_dmbs)266 struct 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 }
299 EXPORT_SYMBOL_GPL(smcd_alloc_dev);
300
smcd_register_dev(struct smcd_dev * smcd)301 int 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 }
309 EXPORT_SYMBOL_GPL(smcd_register_dev);
310
smcd_unregister_dev(struct smcd_dev * smcd)311 void 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 }
322 EXPORT_SYMBOL_GPL(smcd_unregister_dev);
323
smcd_free_dev(struct smcd_dev * smcd)324 void smcd_free_dev(struct smcd_dev *smcd)
325 {
326 put_device(&smcd->dev);
327 }
328 EXPORT_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 */
smcd_handle_event(struct smcd_dev * smcd,struct smcd_event * event)341 void 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 }
354 EXPORT_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 */
smcd_handle_irq(struct smcd_dev * smcd,unsigned int dmbno)363 void 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 }
374 EXPORT_SYMBOL_GPL(smcd_handle_irq);
375