net/smc/smc_ism.c

   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. */
  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
  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. */
  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. */
  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  */
  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  */
 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
 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
 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
 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
 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 */
 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
 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
 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         return smcd;
 293 }
 294 EXPORT_SYMBOL_GPL(smcd_alloc_dev);
 295
 296 int smcd_register_dev(struct smcd_dev *smcd)
 297 {
 298         spin_lock(&smcd_dev_list.lock);
 299         list_add_tail(&smcd->list, &smcd_dev_list.list);
 300         spin_unlock(&smcd_dev_list.lock);
 301
 302         return device_add(&smcd->dev);
 303 }
 304 EXPORT_SYMBOL_GPL(smcd_register_dev);
 305
 306 void smcd_unregister_dev(struct smcd_dev *smcd)
 307 {
 308         spin_lock(&smcd_dev_list.lock);
 309         list_del(&smcd->list);
 310         spin_unlock(&smcd_dev_list.lock);
 311         flush_workqueue(smcd->event_wq);
 312         destroy_workqueue(smcd->event_wq);
 313         smc_smcd_terminate(smcd, 0, VLAN_VID_MASK);
 314
 315         device_del(&smcd->dev);
 316 }
 317 EXPORT_SYMBOL_GPL(smcd_unregister_dev);
 318
 319 void smcd_free_dev(struct smcd_dev *smcd)
 320 {
 321         put_device(&smcd->dev);
 322 }
 323 EXPORT_SYMBOL_GPL(smcd_free_dev);
 324
 325 /* SMCD Device event handler. Called from ISM device interrupt handler.
 326  * Parameters are smcd device pointer,
 327  * - event->type (0 --> DMB, 1 --> GID),
 328  * - event->code (event code),
 329  * - event->tok (either DMB token when event type 0, or GID when event type 1)
 330  * - event->time (time of day)
 331  * - event->info (debug info).
 332  *
 333  * Context:
 334  * - Function called in IRQ context from ISM device driver event handler.
 335  */
 336 void smcd_handle_event(struct smcd_dev *smcd, struct smcd_event *event)
 337 {
 338         struct smc_ism_event_work *wrk;
 339
 340         /* copy event to event work queue, and let it be handled there */
 341         wrk = kmalloc(sizeof(*wrk), GFP_ATOMIC);
 342         if (!wrk)
 343                 return;
 344         INIT_WORK(&wrk->work, smc_ism_event_work);
 345         wrk->smcd = smcd;
 346         wrk->event = *event;
 347         queue_work(smcd->event_wq, &wrk->work);
 348 }
 349 EXPORT_SYMBOL_GPL(smcd_handle_event);
 350
 351 /* SMCD Device interrupt handler. Called from ISM device interrupt handler.
 352  * Parameters are smcd device pointer and DMB number. Find the connection and
 353  * schedule the tasklet for this connection.
 354  *
 355  * Context:
 356  * - Function called in IRQ context from ISM device driver IRQ handler.
 357  */
 358 void smcd_handle_irq(struct smcd_dev *smcd, unsigned int dmbno)
 359 {
 360         struct smc_connection *conn = NULL;
 361         unsigned long flags;
 362
 363         spin_lock_irqsave(&smcd->lock, flags);
 364         conn = smcd->conn[dmbno];
 365         if (conn)
 366                 tasklet_schedule(&conn->rx_tsklet);
 367         spin_unlock_irqrestore(&smcd->lock, flags);
 368 }
 369 EXPORT_SYMBOL_GPL(smcd_handle_irq);