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Linux/arch/sparc/kernel/ldc.c

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  1 /* ldc.c: Logical Domain Channel link-layer protocol driver.
  2  *
  3  * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
  4  */
  5 
  6 #include <linux/kernel.h>
  7 #include <linux/export.h>
  8 #include <linux/slab.h>
  9 #include <linux/spinlock.h>
 10 #include <linux/delay.h>
 11 #include <linux/errno.h>
 12 #include <linux/string.h>
 13 #include <linux/scatterlist.h>
 14 #include <linux/interrupt.h>
 15 #include <linux/list.h>
 16 #include <linux/init.h>
 17 #include <linux/bitmap.h>
 18 
 19 #include <asm/hypervisor.h>
 20 #include <asm/iommu.h>
 21 #include <asm/page.h>
 22 #include <asm/ldc.h>
 23 #include <asm/mdesc.h>
 24 
 25 #define DRV_MODULE_NAME         "ldc"
 26 #define PFX DRV_MODULE_NAME     ": "
 27 #define DRV_MODULE_VERSION      "1.1"
 28 #define DRV_MODULE_RELDATE      "July 22, 2008"
 29 
 30 static char version[] __devinitdata =
 31         DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
 32 #define LDC_PACKET_SIZE         64
 33 
 34 /* Packet header layout for unreliable and reliable mode frames.
 35  * When in RAW mode, packets are simply straight 64-byte payloads
 36  * with no headers.
 37  */
 38 struct ldc_packet {
 39         u8                      type;
 40 #define LDC_CTRL                0x01
 41 #define LDC_DATA                0x02
 42 #define LDC_ERR                 0x10
 43 
 44         u8                      stype;
 45 #define LDC_INFO                0x01
 46 #define LDC_ACK                 0x02
 47 #define LDC_NACK                0x04
 48 
 49         u8                      ctrl;
 50 #define LDC_VERS                0x01 /* Link Version            */
 51 #define LDC_RTS                 0x02 /* Request To Send         */
 52 #define LDC_RTR                 0x03 /* Ready To Receive        */
 53 #define LDC_RDX                 0x04 /* Ready for Data eXchange */
 54 #define LDC_CTRL_MSK            0x0f
 55 
 56         u8                      env;
 57 #define LDC_LEN                 0x3f
 58 #define LDC_FRAG_MASK           0xc0
 59 #define LDC_START               0x40
 60 #define LDC_STOP                0x80
 61 
 62         u32                     seqid;
 63 
 64         union {
 65                 u8              u_data[LDC_PACKET_SIZE - 8];
 66                 struct {
 67                         u32     pad;
 68                         u32     ackid;
 69                         u8      r_data[LDC_PACKET_SIZE - 8 - 8];
 70                 } r;
 71         } u;
 72 };
 73 
 74 struct ldc_version {
 75         u16 major;
 76         u16 minor;
 77 };
 78 
 79 /* Ordered from largest major to lowest.  */
 80 static struct ldc_version ver_arr[] = {
 81         { .major = 1, .minor = 0 },
 82 };
 83 
 84 #define LDC_DEFAULT_MTU                 (4 * LDC_PACKET_SIZE)
 85 #define LDC_DEFAULT_NUM_ENTRIES         (PAGE_SIZE / LDC_PACKET_SIZE)
 86 
 87 struct ldc_channel;
 88 
 89 struct ldc_mode_ops {
 90         int (*write)(struct ldc_channel *, const void *, unsigned int);
 91         int (*read)(struct ldc_channel *, void *, unsigned int);
 92 };
 93 
 94 static const struct ldc_mode_ops raw_ops;
 95 static const struct ldc_mode_ops nonraw_ops;
 96 static const struct ldc_mode_ops stream_ops;
 97 
 98 int ldom_domaining_enabled;
 99 
100 struct ldc_iommu {
101         /* Protects arena alloc/free.  */
102         spinlock_t                      lock;
103         struct iommu_arena              arena;
104         struct ldc_mtable_entry         *page_table;
105 };
106 
107 struct ldc_channel {
108         /* Protects all operations that depend upon channel state.  */
109         spinlock_t                      lock;
110 
111         unsigned long                   id;
112 
113         u8                              *mssbuf;
114         u32                             mssbuf_len;
115         u32                             mssbuf_off;
116 
117         struct ldc_packet               *tx_base;
118         unsigned long                   tx_head;
119         unsigned long                   tx_tail;
120         unsigned long                   tx_num_entries;
121         unsigned long                   tx_ra;
122 
123         unsigned long                   tx_acked;
124 
125         struct ldc_packet               *rx_base;
126         unsigned long                   rx_head;
127         unsigned long                   rx_tail;
128         unsigned long                   rx_num_entries;
129         unsigned long                   rx_ra;
130 
131         u32                             rcv_nxt;
132         u32                             snd_nxt;
133 
134         unsigned long                   chan_state;
135 
136         struct ldc_channel_config       cfg;
137         void                            *event_arg;
138 
139         const struct ldc_mode_ops       *mops;
140 
141         struct ldc_iommu                iommu;
142 
143         struct ldc_version              ver;
144 
145         u8                              hs_state;
146 #define LDC_HS_CLOSED                   0x00
147 #define LDC_HS_OPEN                     0x01
148 #define LDC_HS_GOTVERS                  0x02
149 #define LDC_HS_SENTRTR                  0x03
150 #define LDC_HS_GOTRTR                   0x04
151 #define LDC_HS_COMPLETE                 0x10
152 
153         u8                              flags;
154 #define LDC_FLAG_ALLOCED_QUEUES         0x01
155 #define LDC_FLAG_REGISTERED_QUEUES      0x02
156 #define LDC_FLAG_REGISTERED_IRQS        0x04
157 #define LDC_FLAG_RESET                  0x10
158 
159         u8                              mss;
160         u8                              state;
161 
162 #define LDC_IRQ_NAME_MAX                32
163         char                            rx_irq_name[LDC_IRQ_NAME_MAX];
164         char                            tx_irq_name[LDC_IRQ_NAME_MAX];
165 
166         struct hlist_head               mh_list;
167 
168         struct hlist_node               list;
169 };
170 
171 #define ldcdbg(TYPE, f, a...) \
172 do {    if (lp->cfg.debug & LDC_DEBUG_##TYPE) \
173                 printk(KERN_INFO PFX "ID[%lu] " f, lp->id, ## a); \
174 } while (0)
175 
176 static const char *state_to_str(u8 state)
177 {
178         switch (state) {
179         case LDC_STATE_INVALID:
180                 return "INVALID";
181         case LDC_STATE_INIT:
182                 return "INIT";
183         case LDC_STATE_BOUND:
184                 return "BOUND";
185         case LDC_STATE_READY:
186                 return "READY";
187         case LDC_STATE_CONNECTED:
188                 return "CONNECTED";
189         default:
190                 return "<UNKNOWN>";
191         }
192 }
193 
194 static void ldc_set_state(struct ldc_channel *lp, u8 state)
195 {
196         ldcdbg(STATE, "STATE (%s) --> (%s)\n",
197                state_to_str(lp->state),
198                state_to_str(state));
199 
200         lp->state = state;
201 }
202 
203 static unsigned long __advance(unsigned long off, unsigned long num_entries)
204 {
205         off += LDC_PACKET_SIZE;
206         if (off == (num_entries * LDC_PACKET_SIZE))
207                 off = 0;
208 
209         return off;
210 }
211 
212 static unsigned long rx_advance(struct ldc_channel *lp, unsigned long off)
213 {
214         return __advance(off, lp->rx_num_entries);
215 }
216 
217 static unsigned long tx_advance(struct ldc_channel *lp, unsigned long off)
218 {
219         return __advance(off, lp->tx_num_entries);
220 }
221 
222 static struct ldc_packet *handshake_get_tx_packet(struct ldc_channel *lp,
223                                                   unsigned long *new_tail)
224 {
225         struct ldc_packet *p;
226         unsigned long t;
227 
228         t = tx_advance(lp, lp->tx_tail);
229         if (t == lp->tx_head)
230                 return NULL;
231 
232         *new_tail = t;
233 
234         p = lp->tx_base;
235         return p + (lp->tx_tail / LDC_PACKET_SIZE);
236 }
237 
238 /* When we are in reliable or stream mode, have to track the next packet
239  * we haven't gotten an ACK for in the TX queue using tx_acked.  We have
240  * to be careful not to stomp over the queue past that point.  During
241  * the handshake, we don't have TX data packets pending in the queue
242  * and that's why handshake_get_tx_packet() need not be mindful of
243  * lp->tx_acked.
244  */
245 static unsigned long head_for_data(struct ldc_channel *lp)
246 {
247         if (lp->cfg.mode == LDC_MODE_STREAM)
248                 return lp->tx_acked;
249         return lp->tx_head;
250 }
251 
252 static int tx_has_space_for(struct ldc_channel *lp, unsigned int size)
253 {
254         unsigned long limit, tail, new_tail, diff;
255         unsigned int mss;
256 
257         limit = head_for_data(lp);
258         tail = lp->tx_tail;
259         new_tail = tx_advance(lp, tail);
260         if (new_tail == limit)
261                 return 0;
262 
263         if (limit > new_tail)
264                 diff = limit - new_tail;
265         else
266                 diff = (limit +
267                         ((lp->tx_num_entries * LDC_PACKET_SIZE) - new_tail));
268         diff /= LDC_PACKET_SIZE;
269         mss = lp->mss;
270 
271         if (diff * mss < size)
272                 return 0;
273 
274         return 1;
275 }
276 
277 static struct ldc_packet *data_get_tx_packet(struct ldc_channel *lp,
278                                              unsigned long *new_tail)
279 {
280         struct ldc_packet *p;
281         unsigned long h, t;
282 
283         h = head_for_data(lp);
284         t = tx_advance(lp, lp->tx_tail);
285         if (t == h)
286                 return NULL;
287 
288         *new_tail = t;
289 
290         p = lp->tx_base;
291         return p + (lp->tx_tail / LDC_PACKET_SIZE);
292 }
293 
294 static int set_tx_tail(struct ldc_channel *lp, unsigned long tail)
295 {
296         unsigned long orig_tail = lp->tx_tail;
297         int limit = 1000;
298 
299         lp->tx_tail = tail;
300         while (limit-- > 0) {
301                 unsigned long err;
302 
303                 err = sun4v_ldc_tx_set_qtail(lp->id, tail);
304                 if (!err)
305                         return 0;
306 
307                 if (err != HV_EWOULDBLOCK) {
308                         lp->tx_tail = orig_tail;
309                         return -EINVAL;
310                 }
311                 udelay(1);
312         }
313 
314         lp->tx_tail = orig_tail;
315         return -EBUSY;
316 }
317 
318 /* This just updates the head value in the hypervisor using
319  * a polling loop with a timeout.  The caller takes care of
320  * upating software state representing the head change, if any.
321  */
322 static int __set_rx_head(struct ldc_channel *lp, unsigned long head)
323 {
324         int limit = 1000;
325 
326         while (limit-- > 0) {
327                 unsigned long err;
328 
329                 err = sun4v_ldc_rx_set_qhead(lp->id, head);
330                 if (!err)
331                         return 0;
332 
333                 if (err != HV_EWOULDBLOCK)
334                         return -EINVAL;
335 
336                 udelay(1);
337         }
338 
339         return -EBUSY;
340 }
341 
342 static int send_tx_packet(struct ldc_channel *lp,
343                           struct ldc_packet *p,
344                           unsigned long new_tail)
345 {
346         BUG_ON(p != (lp->tx_base + (lp->tx_tail / LDC_PACKET_SIZE)));
347 
348         return set_tx_tail(lp, new_tail);
349 }
350 
351 static struct ldc_packet *handshake_compose_ctrl(struct ldc_channel *lp,
352                                                  u8 stype, u8 ctrl,
353                                                  void *data, int dlen,
354                                                  unsigned long *new_tail)
355 {
356         struct ldc_packet *p = handshake_get_tx_packet(lp, new_tail);
357 
358         if (p) {
359                 memset(p, 0, sizeof(*p));
360                 p->type = LDC_CTRL;
361                 p->stype = stype;
362                 p->ctrl = ctrl;
363                 if (data)
364                         memcpy(p->u.u_data, data, dlen);
365         }
366         return p;
367 }
368 
369 static int start_handshake(struct ldc_channel *lp)
370 {
371         struct ldc_packet *p;
372         struct ldc_version *ver;
373         unsigned long new_tail;
374 
375         ver = &ver_arr[0];
376 
377         ldcdbg(HS, "SEND VER INFO maj[%u] min[%u]\n",
378                ver->major, ver->minor);
379 
380         p = handshake_compose_ctrl(lp, LDC_INFO, LDC_VERS,
381                                    ver, sizeof(*ver), &new_tail);
382         if (p) {
383                 int err = send_tx_packet(lp, p, new_tail);
384                 if (!err)
385                         lp->flags &= ~LDC_FLAG_RESET;
386                 return err;
387         }
388         return -EBUSY;
389 }
390 
391 static int send_version_nack(struct ldc_channel *lp,
392                              u16 major, u16 minor)
393 {
394         struct ldc_packet *p;
395         struct ldc_version ver;
396         unsigned long new_tail;
397 
398         ver.major = major;
399         ver.minor = minor;
400 
401         p = handshake_compose_ctrl(lp, LDC_NACK, LDC_VERS,
402                                    &ver, sizeof(ver), &new_tail);
403         if (p) {
404                 ldcdbg(HS, "SEND VER NACK maj[%u] min[%u]\n",
405                        ver.major, ver.minor);
406 
407                 return send_tx_packet(lp, p, new_tail);
408         }
409         return -EBUSY;
410 }
411 
412 static int send_version_ack(struct ldc_channel *lp,
413                             struct ldc_version *vp)
414 {
415         struct ldc_packet *p;
416         unsigned long new_tail;
417 
418         p = handshake_compose_ctrl(lp, LDC_ACK, LDC_VERS,
419                                    vp, sizeof(*vp), &new_tail);
420         if (p) {
421                 ldcdbg(HS, "SEND VER ACK maj[%u] min[%u]\n",
422                        vp->major, vp->minor);
423 
424                 return send_tx_packet(lp, p, new_tail);
425         }
426         return -EBUSY;
427 }
428 
429 static int send_rts(struct ldc_channel *lp)
430 {
431         struct ldc_packet *p;
432         unsigned long new_tail;
433 
434         p = handshake_compose_ctrl(lp, LDC_INFO, LDC_RTS, NULL, 0,
435                                    &new_tail);
436         if (p) {
437                 p->env = lp->cfg.mode;
438                 p->seqid = 0;
439                 lp->rcv_nxt = 0;
440 
441                 ldcdbg(HS, "SEND RTS env[0x%x] seqid[0x%x]\n",
442                        p->env, p->seqid);
443 
444                 return send_tx_packet(lp, p, new_tail);
445         }
446         return -EBUSY;
447 }
448 
449 static int send_rtr(struct ldc_channel *lp)
450 {
451         struct ldc_packet *p;
452         unsigned long new_tail;
453 
454         p = handshake_compose_ctrl(lp, LDC_INFO, LDC_RTR, NULL, 0,
455                                    &new_tail);
456         if (p) {
457                 p->env = lp->cfg.mode;
458                 p->seqid = 0;
459 
460                 ldcdbg(HS, "SEND RTR env[0x%x] seqid[0x%x]\n",
461                        p->env, p->seqid);
462 
463                 return send_tx_packet(lp, p, new_tail);
464         }
465         return -EBUSY;
466 }
467 
468 static int send_rdx(struct ldc_channel *lp)
469 {
470         struct ldc_packet *p;
471         unsigned long new_tail;
472 
473         p = handshake_compose_ctrl(lp, LDC_INFO, LDC_RDX, NULL, 0,
474                                    &new_tail);
475         if (p) {
476                 p->env = 0;
477                 p->seqid = ++lp->snd_nxt;
478                 p->u.r.ackid = lp->rcv_nxt;
479 
480                 ldcdbg(HS, "SEND RDX env[0x%x] seqid[0x%x] ackid[0x%x]\n",
481                        p->env, p->seqid, p->u.r.ackid);
482 
483                 return send_tx_packet(lp, p, new_tail);
484         }
485         return -EBUSY;
486 }
487 
488 static int send_data_nack(struct ldc_channel *lp, struct ldc_packet *data_pkt)
489 {
490         struct ldc_packet *p;
491         unsigned long new_tail;
492         int err;
493 
494         p = data_get_tx_packet(lp, &new_tail);
495         if (!p)
496                 return -EBUSY;
497         memset(p, 0, sizeof(*p));
498         p->type = data_pkt->type;
499         p->stype = LDC_NACK;
500         p->ctrl = data_pkt->ctrl & LDC_CTRL_MSK;
501         p->seqid = lp->snd_nxt + 1;
502         p->u.r.ackid = lp->rcv_nxt;
503 
504         ldcdbg(HS, "SEND DATA NACK type[0x%x] ctl[0x%x] seq[0x%x] ack[0x%x]\n",
505                p->type, p->ctrl, p->seqid, p->u.r.ackid);
506 
507         err = send_tx_packet(lp, p, new_tail);
508         if (!err)
509                 lp->snd_nxt++;
510 
511         return err;
512 }
513 
514 static int ldc_abort(struct ldc_channel *lp)
515 {
516         unsigned long hv_err;
517 
518         ldcdbg(STATE, "ABORT\n");
519 
520         /* We report but do not act upon the hypervisor errors because
521          * there really isn't much we can do if they fail at this point.
522          */
523         hv_err = sun4v_ldc_tx_qconf(lp->id, lp->tx_ra, lp->tx_num_entries);
524         if (hv_err)
525                 printk(KERN_ERR PFX "ldc_abort: "
526                        "sun4v_ldc_tx_qconf(%lx,%lx,%lx) failed, err=%lu\n",
527                        lp->id, lp->tx_ra, lp->tx_num_entries, hv_err);
528 
529         hv_err = sun4v_ldc_tx_get_state(lp->id,
530                                         &lp->tx_head,
531                                         &lp->tx_tail,
532                                         &lp->chan_state);
533         if (hv_err)
534                 printk(KERN_ERR PFX "ldc_abort: "
535                        "sun4v_ldc_tx_get_state(%lx,...) failed, err=%lu\n",
536                        lp->id, hv_err);
537 
538         hv_err = sun4v_ldc_rx_qconf(lp->id, lp->rx_ra, lp->rx_num_entries);
539         if (hv_err)
540                 printk(KERN_ERR PFX "ldc_abort: "
541                        "sun4v_ldc_rx_qconf(%lx,%lx,%lx) failed, err=%lu\n",
542                        lp->id, lp->rx_ra, lp->rx_num_entries, hv_err);
543 
544         /* Refetch the RX queue state as well, because we could be invoked
545          * here in the queue processing context.
546          */
547         hv_err = sun4v_ldc_rx_get_state(lp->id,
548                                         &lp->rx_head,
549                                         &lp->rx_tail,
550                                         &lp->chan_state);
551         if (hv_err)
552                 printk(KERN_ERR PFX "ldc_abort: "
553                        "sun4v_ldc_rx_get_state(%lx,...) failed, err=%lu\n",
554                        lp->id, hv_err);
555 
556         return -ECONNRESET;
557 }
558 
559 static struct ldc_version *find_by_major(u16 major)
560 {
561         struct ldc_version *ret = NULL;
562         int i;
563 
564         for (i = 0; i < ARRAY_SIZE(ver_arr); i++) {
565                 struct ldc_version *v = &ver_arr[i];
566                 if (v->major <= major) {
567                         ret = v;
568                         break;
569                 }
570         }
571         return ret;
572 }
573 
574 static int process_ver_info(struct ldc_channel *lp, struct ldc_version *vp)
575 {
576         struct ldc_version *vap;
577         int err;
578 
579         ldcdbg(HS, "GOT VERSION INFO major[%x] minor[%x]\n",
580                vp->major, vp->minor);
581 
582         if (lp->hs_state == LDC_HS_GOTVERS) {
583                 lp->hs_state = LDC_HS_OPEN;
584                 memset(&lp->ver, 0, sizeof(lp->ver));
585         }
586 
587         vap = find_by_major(vp->major);
588         if (!vap) {
589                 err = send_version_nack(lp, 0, 0);
590         } else if (vap->major != vp->major) {
591                 err = send_version_nack(lp, vap->major, vap->minor);
592         } else {
593                 struct ldc_version ver = *vp;
594                 if (ver.minor > vap->minor)
595                         ver.minor = vap->minor;
596                 err = send_version_ack(lp, &ver);
597                 if (!err) {
598                         lp->ver = ver;
599                         lp->hs_state = LDC_HS_GOTVERS;
600                 }
601         }
602         if (err)
603                 return ldc_abort(lp);
604 
605         return 0;
606 }
607 
608 static int process_ver_ack(struct ldc_channel *lp, struct ldc_version *vp)
609 {
610         ldcdbg(HS, "GOT VERSION ACK major[%x] minor[%x]\n",
611                vp->major, vp->minor);
612 
613         if (lp->hs_state == LDC_HS_GOTVERS) {
614                 if (lp->ver.major != vp->major ||
615                     lp->ver.minor != vp->minor)
616                         return ldc_abort(lp);
617         } else {
618                 lp->ver = *vp;
619                 lp->hs_state = LDC_HS_GOTVERS;
620         }
621         if (send_rts(lp))
622                 return ldc_abort(lp);
623         return 0;
624 }
625 
626 static int process_ver_nack(struct ldc_channel *lp, struct ldc_version *vp)
627 {
628         struct ldc_version *vap;
629         struct ldc_packet *p;
630         unsigned long new_tail;
631 
632         if (vp->major == 0 && vp->minor == 0)
633                 return ldc_abort(lp);
634 
635         vap = find_by_major(vp->major);
636         if (!vap)
637                 return ldc_abort(lp);
638 
639         p = handshake_compose_ctrl(lp, LDC_INFO, LDC_VERS,
640                                            vap, sizeof(*vap),
641                                            &new_tail);
642         if (!p)
643                 return ldc_abort(lp);
644 
645         return send_tx_packet(lp, p, new_tail);
646 }
647 
648 static int process_version(struct ldc_channel *lp,
649                            struct ldc_packet *p)
650 {
651         struct ldc_version *vp;
652 
653         vp = (struct ldc_version *) p->u.u_data;
654 
655         switch (p->stype) {
656         case LDC_INFO:
657                 return process_ver_info(lp, vp);
658 
659         case LDC_ACK:
660                 return process_ver_ack(lp, vp);
661 
662         case LDC_NACK:
663                 return process_ver_nack(lp, vp);
664 
665         default:
666                 return ldc_abort(lp);
667         }
668 }
669 
670 static int process_rts(struct ldc_channel *lp,
671                        struct ldc_packet *p)
672 {
673         ldcdbg(HS, "GOT RTS stype[%x] seqid[%x] env[%x]\n",
674                p->stype, p->seqid, p->env);
675 
676         if (p->stype     != LDC_INFO       ||
677             lp->hs_state != LDC_HS_GOTVERS ||
678             p->env       != lp->cfg.mode)
679                 return ldc_abort(lp);
680 
681         lp->snd_nxt = p->seqid;
682         lp->rcv_nxt = p->seqid;
683         lp->hs_state = LDC_HS_SENTRTR;
684         if (send_rtr(lp))
685                 return ldc_abort(lp);
686 
687         return 0;
688 }
689 
690 static int process_rtr(struct ldc_channel *lp,
691                        struct ldc_packet *p)
692 {
693         ldcdbg(HS, "GOT RTR stype[%x] seqid[%x] env[%x]\n",
694                p->stype, p->seqid, p->env);
695 
696         if (p->stype     != LDC_INFO ||
697             p->env       != lp->cfg.mode)
698                 return ldc_abort(lp);
699 
700         lp->snd_nxt = p->seqid;
701         lp->hs_state = LDC_HS_COMPLETE;
702         ldc_set_state(lp, LDC_STATE_CONNECTED);
703         send_rdx(lp);
704 
705         return LDC_EVENT_UP;
706 }
707 
708 static int rx_seq_ok(struct ldc_channel *lp, u32 seqid)
709 {
710         return lp->rcv_nxt + 1 == seqid;
711 }
712 
713 static int process_rdx(struct ldc_channel *lp,
714                        struct ldc_packet *p)
715 {
716         ldcdbg(HS, "GOT RDX stype[%x] seqid[%x] env[%x] ackid[%x]\n",
717                p->stype, p->seqid, p->env, p->u.r.ackid);
718 
719         if (p->stype != LDC_INFO ||
720             !(rx_seq_ok(lp, p->seqid)))
721                 return ldc_abort(lp);
722 
723         lp->rcv_nxt = p->seqid;
724 
725         lp->hs_state = LDC_HS_COMPLETE;
726         ldc_set_state(lp, LDC_STATE_CONNECTED);
727 
728         return LDC_EVENT_UP;
729 }
730 
731 static int process_control_frame(struct ldc_channel *lp,
732                                  struct ldc_packet *p)
733 {
734         switch (p->ctrl) {
735         case LDC_VERS:
736                 return process_version(lp, p);
737 
738         case LDC_RTS:
739                 return process_rts(lp, p);
740 
741         case LDC_RTR:
742                 return process_rtr(lp, p);
743 
744         case LDC_RDX:
745                 return process_rdx(lp, p);
746 
747         default:
748                 return ldc_abort(lp);
749         }
750 }
751 
752 static int process_error_frame(struct ldc_channel *lp,
753                                struct ldc_packet *p)
754 {
755         return ldc_abort(lp);
756 }
757 
758 static int process_data_ack(struct ldc_channel *lp,
759                             struct ldc_packet *ack)
760 {
761         unsigned long head = lp->tx_acked;
762         u32 ackid = ack->u.r.ackid;
763 
764         while (1) {
765                 struct ldc_packet *p = lp->tx_base + (head / LDC_PACKET_SIZE);
766 
767                 head = tx_advance(lp, head);
768 
769                 if (p->seqid == ackid) {
770                         lp->tx_acked = head;
771                         return 0;
772                 }
773                 if (head == lp->tx_tail)
774                         return ldc_abort(lp);
775         }
776 
777         return 0;
778 }
779 
780 static void send_events(struct ldc_channel *lp, unsigned int event_mask)
781 {
782         if (event_mask & LDC_EVENT_RESET)
783                 lp->cfg.event(lp->event_arg, LDC_EVENT_RESET);
784         if (event_mask & LDC_EVENT_UP)
785                 lp->cfg.event(lp->event_arg, LDC_EVENT_UP);
786         if (event_mask & LDC_EVENT_DATA_READY)
787                 lp->cfg.event(lp->event_arg, LDC_EVENT_DATA_READY);
788 }
789 
790 static irqreturn_t ldc_rx(int irq, void *dev_id)
791 {
792         struct ldc_channel *lp = dev_id;
793         unsigned long orig_state, flags;
794         unsigned int event_mask;
795 
796         spin_lock_irqsave(&lp->lock, flags);
797 
798         orig_state = lp->chan_state;
799 
800         /* We should probably check for hypervisor errors here and
801          * reset the LDC channel if we get one.
802          */
803         sun4v_ldc_rx_get_state(lp->id,
804                                &lp->rx_head,
805                                &lp->rx_tail,
806                                &lp->chan_state);
807 
808         ldcdbg(RX, "RX state[0x%02lx:0x%02lx] head[0x%04lx] tail[0x%04lx]\n",
809                orig_state, lp->chan_state, lp->rx_head, lp->rx_tail);
810 
811         event_mask = 0;
812 
813         if (lp->cfg.mode == LDC_MODE_RAW &&
814             lp->chan_state == LDC_CHANNEL_UP) {
815                 lp->hs_state = LDC_HS_COMPLETE;
816                 ldc_set_state(lp, LDC_STATE_CONNECTED);
817 
818                 event_mask |= LDC_EVENT_UP;
819 
820                 orig_state = lp->chan_state;
821         }
822 
823         /* If we are in reset state, flush the RX queue and ignore
824          * everything.
825          */
826         if (lp->flags & LDC_FLAG_RESET) {
827                 (void) __set_rx_head(lp, lp->rx_tail);
828                 goto out;
829         }
830 
831         /* Once we finish the handshake, we let the ldc_read()
832          * paths do all of the control frame and state management.
833          * Just trigger the callback.
834          */
835         if (lp->hs_state == LDC_HS_COMPLETE) {
836 handshake_complete:
837                 if (lp->chan_state != orig_state) {
838                         unsigned int event = LDC_EVENT_RESET;
839 
840                         if (lp->chan_state == LDC_CHANNEL_UP)
841                                 event = LDC_EVENT_UP;
842 
843                         event_mask |= event;
844                 }
845                 if (lp->rx_head != lp->rx_tail)
846                         event_mask |= LDC_EVENT_DATA_READY;
847 
848                 goto out;
849         }
850 
851         if (lp->chan_state != orig_state)
852                 goto out;
853 
854         while (lp->rx_head != lp->rx_tail) {
855                 struct ldc_packet *p;
856                 unsigned long new;
857                 int err;
858 
859                 p = lp->rx_base + (lp->rx_head / LDC_PACKET_SIZE);
860 
861                 switch (p->type) {
862                 case LDC_CTRL:
863                         err = process_control_frame(lp, p);
864                         if (err > 0)
865                                 event_mask |= err;
866                         break;
867 
868                 case LDC_DATA:
869                         event_mask |= LDC_EVENT_DATA_READY;
870                         err = 0;
871                         break;
872 
873                 case LDC_ERR:
874                         err = process_error_frame(lp, p);
875                         break;
876 
877                 default:
878                         err = ldc_abort(lp);
879                         break;
880                 }
881 
882                 if (err < 0)
883                         break;
884 
885                 new = lp->rx_head;
886                 new += LDC_PACKET_SIZE;
887                 if (new == (lp->rx_num_entries * LDC_PACKET_SIZE))
888                         new = 0;
889                 lp->rx_head = new;
890 
891                 err = __set_rx_head(lp, new);
892                 if (err < 0) {
893                         (void) ldc_abort(lp);
894                         break;
895                 }
896                 if (lp->hs_state == LDC_HS_COMPLETE)
897                         goto handshake_complete;
898         }
899 
900 out:
901         spin_unlock_irqrestore(&lp->lock, flags);
902 
903         send_events(lp, event_mask);
904 
905         return IRQ_HANDLED;
906 }
907 
908 static irqreturn_t ldc_tx(int irq, void *dev_id)
909 {
910         struct ldc_channel *lp = dev_id;
911         unsigned long flags, orig_state;
912         unsigned int event_mask = 0;
913 
914         spin_lock_irqsave(&lp->lock, flags);
915 
916         orig_state = lp->chan_state;
917 
918         /* We should probably check for hypervisor errors here and
919          * reset the LDC channel if we get one.
920          */
921         sun4v_ldc_tx_get_state(lp->id,
922                                &lp->tx_head,
923                                &lp->tx_tail,
924                                &lp->chan_state);
925 
926         ldcdbg(TX, " TX state[0x%02lx:0x%02lx] head[0x%04lx] tail[0x%04lx]\n",
927                orig_state, lp->chan_state, lp->tx_head, lp->tx_tail);
928 
929         if (lp->cfg.mode == LDC_MODE_RAW &&
930             lp->chan_state == LDC_CHANNEL_UP) {
931                 lp->hs_state = LDC_HS_COMPLETE;
932                 ldc_set_state(lp, LDC_STATE_CONNECTED);
933 
934                 event_mask |= LDC_EVENT_UP;
935         }
936 
937         spin_unlock_irqrestore(&lp->lock, flags);
938 
939         send_events(lp, event_mask);
940 
941         return IRQ_HANDLED;
942 }
943 
944 /* XXX ldc_alloc() and ldc_free() needs to run under a mutex so
945  * XXX that addition and removal from the ldc_channel_list has
946  * XXX atomicity, otherwise the __ldc_channel_exists() check is
947  * XXX totally pointless as another thread can slip into ldc_alloc()
948  * XXX and add a channel with the same ID.  There also needs to be
949  * XXX a spinlock for ldc_channel_list.
950  */
951 static HLIST_HEAD(ldc_channel_list);
952 
953 static int __ldc_channel_exists(unsigned long id)
954 {
955         struct ldc_channel *lp;
956         struct hlist_node *n;
957 
958         hlist_for_each_entry(lp, n, &ldc_channel_list, list) {
959                 if (lp->id == id)
960                         return 1;
961         }
962         return 0;
963 }
964 
965 static int alloc_queue(const char *name, unsigned long num_entries,
966                        struct ldc_packet **base, unsigned long *ra)
967 {
968         unsigned long size, order;
969         void *q;
970 
971         size = num_entries * LDC_PACKET_SIZE;
972         order = get_order(size);
973 
974         q = (void *) __get_free_pages(GFP_KERNEL, order);
975         if (!q) {
976                 printk(KERN_ERR PFX "Alloc of %s queue failed with "
977                        "size=%lu order=%lu\n", name, size, order);
978                 return -ENOMEM;
979         }
980 
981         memset(q, 0, PAGE_SIZE << order);
982 
983         *base = q;
984         *ra = __pa(q);
985 
986         return 0;
987 }
988 
989 static void free_queue(unsigned long num_entries, struct ldc_packet *q)
990 {
991         unsigned long size, order;
992 
993         if (!q)
994                 return;
995 
996         size = num_entries * LDC_PACKET_SIZE;
997         order = get_order(size);
998 
999         free_pages((unsigned long)q, order);
1000 }
1001 
1002 /* XXX Make this configurable... XXX */
1003 #define LDC_IOTABLE_SIZE        (8 * 1024)
1004 
1005 static int ldc_iommu_init(struct ldc_channel *lp)
1006 {
1007         unsigned long sz, num_tsb_entries, tsbsize, order;
1008         struct ldc_iommu *iommu = &lp->iommu;
1009         struct ldc_mtable_entry *table;
1010         unsigned long hv_err;
1011         int err;
1012 
1013         num_tsb_entries = LDC_IOTABLE_SIZE;
1014         tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
1015 
1016         spin_lock_init(&iommu->lock);
1017 
1018         sz = num_tsb_entries / 8;
1019         sz = (sz + 7UL) & ~7UL;
1020         iommu->arena.map = kzalloc(sz, GFP_KERNEL);
1021         if (!iommu->arena.map) {
1022                 printk(KERN_ERR PFX "Alloc of arena map failed, sz=%lu\n", sz);
1023                 return -ENOMEM;
1024         }
1025 
1026         iommu->arena.limit = num_tsb_entries;
1027 
1028         order = get_order(tsbsize);
1029 
1030         table = (struct ldc_mtable_entry *)
1031                 __get_free_pages(GFP_KERNEL, order);
1032         err = -ENOMEM;
1033         if (!table) {
1034                 printk(KERN_ERR PFX "Alloc of MTE table failed, "
1035                        "size=%lu order=%lu\n", tsbsize, order);
1036                 goto out_free_map;
1037         }
1038 
1039         memset(table, 0, PAGE_SIZE << order);
1040 
1041         iommu->page_table = table;
1042 
1043         hv_err = sun4v_ldc_set_map_table(lp->id, __pa(table),
1044                                          num_tsb_entries);
1045         err = -EINVAL;
1046         if (hv_err)
1047                 goto out_free_table;
1048 
1049         return 0;
1050 
1051 out_free_table:
1052         free_pages((unsigned long) table, order);
1053         iommu->page_table = NULL;
1054 
1055 out_free_map:
1056         kfree(iommu->arena.map);
1057         iommu->arena.map = NULL;
1058 
1059         return err;
1060 }
1061 
1062 static void ldc_iommu_release(struct ldc_channel *lp)
1063 {
1064         struct ldc_iommu *iommu = &lp->iommu;
1065         unsigned long num_tsb_entries, tsbsize, order;
1066 
1067         (void) sun4v_ldc_set_map_table(lp->id, 0, 0);
1068 
1069         num_tsb_entries = iommu->arena.limit;
1070         tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
1071         order = get_order(tsbsize);
1072 
1073         free_pages((unsigned long) iommu->page_table, order);
1074         iommu->page_table = NULL;
1075 
1076         kfree(iommu->arena.map);
1077         iommu->arena.map = NULL;
1078 }
1079 
1080 struct ldc_channel *ldc_alloc(unsigned long id,
1081                               const struct ldc_channel_config *cfgp,
1082                               void *event_arg)
1083 {
1084         struct ldc_channel *lp;
1085         const struct ldc_mode_ops *mops;
1086         unsigned long dummy1, dummy2, hv_err;
1087         u8 mss, *mssbuf;
1088         int err;
1089 
1090         err = -ENODEV;
1091         if (!ldom_domaining_enabled)
1092                 goto out_err;
1093 
1094         err = -EINVAL;
1095         if (!cfgp)
1096                 goto out_err;
1097 
1098         switch (cfgp->mode) {
1099         case LDC_MODE_RAW:
1100                 mops = &raw_ops;
1101                 mss = LDC_PACKET_SIZE;
1102                 break;
1103 
1104         case LDC_MODE_UNRELIABLE:
1105                 mops = &nonraw_ops;
1106                 mss = LDC_PACKET_SIZE - 8;
1107                 break;
1108 
1109         case LDC_MODE_STREAM:
1110                 mops = &stream_ops;
1111                 mss = LDC_PACKET_SIZE - 8 - 8;
1112                 break;
1113 
1114         default:
1115                 goto out_err;
1116         }
1117 
1118         if (!cfgp->event || !event_arg || !cfgp->rx_irq || !cfgp->tx_irq)
1119                 goto out_err;
1120 
1121         hv_err = sun4v_ldc_tx_qinfo(id, &dummy1, &dummy2);
1122         err = -ENODEV;
1123         if (hv_err == HV_ECHANNEL)
1124                 goto out_err;
1125 
1126         err = -EEXIST;
1127         if (__ldc_channel_exists(id))
1128                 goto out_err;
1129 
1130         mssbuf = NULL;
1131 
1132         lp = kzalloc(sizeof(*lp), GFP_KERNEL);
1133         err = -ENOMEM;
1134         if (!lp)
1135                 goto out_err;
1136 
1137         spin_lock_init(&lp->lock);
1138 
1139         lp->id = id;
1140 
1141         err = ldc_iommu_init(lp);
1142         if (err)
1143                 goto out_free_ldc;
1144 
1145         lp->mops = mops;
1146         lp->mss = mss;
1147 
1148         lp->cfg = *cfgp;
1149         if (!lp->cfg.mtu)
1150                 lp->cfg.mtu = LDC_DEFAULT_MTU;
1151 
1152         if (lp->cfg.mode == LDC_MODE_STREAM) {
1153                 mssbuf = kzalloc(lp->cfg.mtu, GFP_KERNEL);
1154                 if (!mssbuf) {
1155                         err = -ENOMEM;
1156                         goto out_free_iommu;
1157                 }
1158                 lp->mssbuf = mssbuf;
1159         }
1160 
1161         lp->event_arg = event_arg;
1162 
1163         /* XXX allow setting via ldc_channel_config to override defaults
1164          * XXX or use some formula based upon mtu
1165          */
1166         lp->tx_num_entries = LDC_DEFAULT_NUM_ENTRIES;
1167         lp->rx_num_entries = LDC_DEFAULT_NUM_ENTRIES;
1168 
1169         err = alloc_queue("TX", lp->tx_num_entries,
1170                           &lp->tx_base, &lp->tx_ra);
1171         if (err)
1172                 goto out_free_mssbuf;
1173 
1174         err = alloc_queue("RX", lp->rx_num_entries,
1175                           &lp->rx_base, &lp->rx_ra);
1176         if (err)
1177                 goto out_free_txq;
1178 
1179         lp->flags |= LDC_FLAG_ALLOCED_QUEUES;
1180 
1181         lp->hs_state = LDC_HS_CLOSED;
1182         ldc_set_state(lp, LDC_STATE_INIT);
1183 
1184         INIT_HLIST_NODE(&lp->list);
1185         hlist_add_head(&lp->list, &ldc_channel_list);
1186 
1187         INIT_HLIST_HEAD(&lp->mh_list);
1188 
1189         return lp;
1190 
1191 out_free_txq:
1192         free_queue(lp->tx_num_entries, lp->tx_base);
1193 
1194 out_free_mssbuf:
1195         kfree(mssbuf);
1196 
1197 out_free_iommu:
1198         ldc_iommu_release(lp);
1199 
1200 out_free_ldc:
1201         kfree(lp);
1202 
1203 out_err:
1204         return ERR_PTR(err);
1205 }
1206 EXPORT_SYMBOL(ldc_alloc);
1207 
1208 void ldc_free(struct ldc_channel *lp)
1209 {
1210         if (lp->flags & LDC_FLAG_REGISTERED_IRQS) {
1211                 free_irq(lp->cfg.rx_irq, lp);
1212                 free_irq(lp->cfg.tx_irq, lp);
1213         }
1214 
1215         if (lp->flags & LDC_FLAG_REGISTERED_QUEUES) {
1216                 sun4v_ldc_tx_qconf(lp->id, 0, 0);
1217                 sun4v_ldc_rx_qconf(lp->id, 0, 0);
1218                 lp->flags &= ~LDC_FLAG_REGISTERED_QUEUES;
1219         }
1220         if (lp->flags & LDC_FLAG_ALLOCED_QUEUES) {
1221                 free_queue(lp->tx_num_entries, lp->tx_base);
1222                 free_queue(lp->rx_num_entries, lp->rx_base);
1223                 lp->flags &= ~LDC_FLAG_ALLOCED_QUEUES;
1224         }
1225 
1226         hlist_del(&lp->list);
1227 
1228         kfree(lp->mssbuf);
1229 
1230         ldc_iommu_release(lp);
1231 
1232         kfree(lp);
1233 }
1234 EXPORT_SYMBOL(ldc_free);
1235 
1236 /* Bind the channel.  This registers the LDC queues with
1237  * the hypervisor and puts the channel into a pseudo-listening
1238  * state.  This does not initiate a handshake, ldc_connect() does
1239  * that.
1240  */
1241 int ldc_bind(struct ldc_channel *lp, const char *name)
1242 {
1243         unsigned long hv_err, flags;
1244         int err = -EINVAL;
1245 
1246         if (!name ||
1247             (lp->state != LDC_STATE_INIT))
1248                 return -EINVAL;
1249 
1250         snprintf(lp->rx_irq_name, LDC_IRQ_NAME_MAX, "%s RX", name);
1251         snprintf(lp->tx_irq_name, LDC_IRQ_NAME_MAX, "%s TX", name);
1252 
1253         err = request_irq(lp->cfg.rx_irq, ldc_rx,
1254                           IRQF_SAMPLE_RANDOM | IRQF_DISABLED,
1255                           lp->rx_irq_name, lp);
1256         if (err)
1257                 return err;
1258 
1259         err = request_irq(lp->cfg.tx_irq, ldc_tx,
1260                           IRQF_SAMPLE_RANDOM | IRQF_DISABLED,
1261                           lp->tx_irq_name, lp);
1262         if (err) {
1263                 free_irq(lp->cfg.rx_irq, lp);
1264                 return err;
1265         }
1266 
1267 
1268         spin_lock_irqsave(&lp->lock, flags);
1269 
1270         enable_irq(lp->cfg.rx_irq);
1271         enable_irq(lp->cfg.tx_irq);
1272 
1273         lp->flags |= LDC_FLAG_REGISTERED_IRQS;
1274 
1275         err = -ENODEV;
1276         hv_err = sun4v_ldc_tx_qconf(lp->id, 0, 0);
1277         if (hv_err)
1278                 goto out_free_irqs;
1279 
1280         hv_err = sun4v_ldc_tx_qconf(lp->id, lp->tx_ra, lp->tx_num_entries);
1281         if (hv_err)
1282                 goto out_free_irqs;
1283 
1284         hv_err = sun4v_ldc_rx_qconf(lp->id, 0, 0);
1285         if (hv_err)
1286                 goto out_unmap_tx;
1287 
1288         hv_err = sun4v_ldc_rx_qconf(lp->id, lp->rx_ra, lp->rx_num_entries);
1289         if (hv_err)
1290                 goto out_unmap_tx;
1291 
1292         lp->flags |= LDC_FLAG_REGISTERED_QUEUES;
1293 
1294         hv_err = sun4v_ldc_tx_get_state(lp->id,
1295                                         &lp->tx_head,
1296                                         &lp->tx_tail,
1297                                         &lp->chan_state);
1298         err = -EBUSY;
1299         if (hv_err)
1300                 goto out_unmap_rx;
1301 
1302         lp->tx_acked = lp->tx_head;
1303 
1304         lp->hs_state = LDC_HS_OPEN;
1305         ldc_set_state(lp, LDC_STATE_BOUND);
1306 
1307         spin_unlock_irqrestore(&lp->lock, flags);
1308 
1309         return 0;
1310 
1311 out_unmap_rx:
1312         lp->flags &= ~LDC_FLAG_REGISTERED_QUEUES;
1313         sun4v_ldc_rx_qconf(lp->id, 0, 0);
1314 
1315 out_unmap_tx:
1316         sun4v_ldc_tx_qconf(lp->id, 0, 0);
1317 
1318 out_free_irqs:
1319         lp->flags &= ~LDC_FLAG_REGISTERED_IRQS;
1320         free_irq(lp->cfg.tx_irq, lp);
1321         free_irq(lp->cfg.rx_irq, lp);
1322 
1323         spin_unlock_irqrestore(&lp->lock, flags);
1324 
1325         return err;
1326 }
1327 EXPORT_SYMBOL(ldc_bind);
1328 
1329 int ldc_connect(struct ldc_channel *lp)
1330 {
1331         unsigned long flags;
1332         int err;
1333 
1334         if (lp->cfg.mode == LDC_MODE_RAW)
1335                 return -EINVAL;
1336 
1337         spin_lock_irqsave(&lp->lock, flags);
1338 
1339         if (!(lp->flags & LDC_FLAG_ALLOCED_QUEUES) ||
1340             !(lp->flags & LDC_FLAG_REGISTERED_QUEUES) ||
1341             lp->hs_state != LDC_HS_OPEN)
1342                 err = -EINVAL;
1343         else
1344                 err = start_handshake(lp);
1345 
1346         spin_unlock_irqrestore(&lp->lock, flags);
1347 
1348         return err;
1349 }
1350 EXPORT_SYMBOL(ldc_connect);
1351 
1352 int ldc_disconnect(struct ldc_channel *lp)
1353 {
1354         unsigned long hv_err, flags;
1355         int err;
1356 
1357         if (lp->cfg.mode == LDC_MODE_RAW)
1358                 return -EINVAL;
1359 
1360         if (!(lp->flags & LDC_FLAG_ALLOCED_QUEUES) ||
1361             !(lp->flags & LDC_FLAG_REGISTERED_QUEUES))
1362                 return -EINVAL;
1363 
1364         spin_lock_irqsave(&lp->lock, flags);
1365 
1366         err = -ENODEV;
1367         hv_err = sun4v_ldc_tx_qconf(lp->id, 0, 0);
1368         if (hv_err)
1369                 goto out_err;
1370 
1371         hv_err = sun4v_ldc_tx_qconf(lp->id, lp->tx_ra, lp->tx_num_entries);
1372         if (hv_err)
1373                 goto out_err;
1374 
1375         hv_err = sun4v_ldc_rx_qconf(lp->id, 0, 0);
1376         if (hv_err)
1377                 goto out_err;
1378 
1379         hv_err = sun4v_ldc_rx_qconf(lp->id, lp->rx_ra, lp->rx_num_entries);
1380         if (hv_err)
1381                 goto out_err;
1382 
1383         ldc_set_state(lp, LDC_STATE_BOUND);
1384         lp->hs_state = LDC_HS_OPEN;
1385         lp->flags |= LDC_FLAG_RESET;
1386 
1387         spin_unlock_irqrestore(&lp->lock, flags);
1388 
1389         return 0;
1390 
1391 out_err:
1392         sun4v_ldc_tx_qconf(lp->id, 0, 0);
1393         sun4v_ldc_rx_qconf(lp->id, 0, 0);
1394         free_irq(lp->cfg.tx_irq, lp);
1395         free_irq(lp->cfg.rx_irq, lp);
1396         lp->flags &= ~(LDC_FLAG_REGISTERED_IRQS |
1397                        LDC_FLAG_REGISTERED_QUEUES);
1398         ldc_set_state(lp, LDC_STATE_INIT);
1399 
1400         spin_unlock_irqrestore(&lp->lock, flags);
1401 
1402         return err;
1403 }
1404 EXPORT_SYMBOL(ldc_disconnect);
1405 
1406 int ldc_state(struct ldc_channel *lp)
1407 {
1408         return lp->state;
1409 }
1410 EXPORT_SYMBOL(ldc_state);
1411 
1412 static int write_raw(struct ldc_channel *lp, const void *buf, unsigned int size)
1413 {
1414         struct ldc_packet *p;
1415         unsigned long new_tail;
1416         int err;
1417 
1418         if (size > LDC_PACKET_SIZE)
1419                 return -EMSGSIZE;
1420 
1421         p = data_get_tx_packet(lp, &new_tail);
1422         if (!p)
1423                 return -EAGAIN;
1424 
1425         memcpy(p, buf, size);
1426 
1427         err = send_tx_packet(lp, p, new_tail);
1428         if (!err)
1429                 err = size;
1430 
1431         return err;
1432 }
1433 
1434 static int read_raw(struct ldc_channel *lp, void *buf, unsigned int size)
1435 {
1436         struct ldc_packet *p;
1437         unsigned long hv_err, new;
1438         int err;
1439 
1440         if (size < LDC_PACKET_SIZE)
1441                 return -EINVAL;
1442 
1443         hv_err = sun4v_ldc_rx_get_state(lp->id,
1444                                         &lp->rx_head,
1445                                         &lp->rx_tail,
1446                                         &lp->chan_state);
1447         if (hv_err)
1448                 return ldc_abort(lp);
1449 
1450         if (lp->chan_state == LDC_CHANNEL_DOWN ||
1451             lp->chan_state == LDC_CHANNEL_RESETTING)
1452                 return -ECONNRESET;
1453 
1454         if (lp->rx_head == lp->rx_tail)
1455                 return 0;
1456 
1457         p = lp->rx_base + (lp->rx_head / LDC_PACKET_SIZE);
1458         memcpy(buf, p, LDC_PACKET_SIZE);
1459 
1460         new = rx_advance(lp, lp->rx_head);
1461         lp->rx_head = new;
1462 
1463         err = __set_rx_head(lp, new);
1464         if (err < 0)
1465                 err = -ECONNRESET;
1466         else
1467                 err = LDC_PACKET_SIZE;
1468 
1469         return err;
1470 }
1471 
1472 static const struct ldc_mode_ops raw_ops = {
1473         .write          =       write_raw,
1474         .read           =       read_raw,
1475 };
1476 
1477 static int write_nonraw(struct ldc_channel *lp, const void *buf,
1478                         unsigned int size)
1479 {
1480         unsigned long hv_err, tail;
1481         unsigned int copied;
1482         u32 seq;
1483         int err;
1484 
1485         hv_err = sun4v_ldc_tx_get_state(lp->id, &lp->tx_head, &lp->tx_tail,
1486                                         &lp->chan_state);
1487         if (unlikely(hv_err))
1488                 return -EBUSY;
1489 
1490         if (unlikely(lp->chan_state != LDC_CHANNEL_UP))
1491                 return ldc_abort(lp);
1492 
1493         if (!tx_has_space_for(lp, size))
1494                 return -EAGAIN;
1495 
1496         seq = lp->snd_nxt;
1497         copied = 0;
1498         tail = lp->tx_tail;
1499         while (copied < size) {
1500                 struct ldc_packet *p = lp->tx_base + (tail / LDC_PACKET_SIZE);
1501                 u8 *data = ((lp->cfg.mode == LDC_MODE_UNRELIABLE) ?
1502                             p->u.u_data :
1503                             p->u.r.r_data);
1504                 int data_len;
1505 
1506                 p->type = LDC_DATA;
1507                 p->stype = LDC_INFO;
1508                 p->ctrl = 0;
1509 
1510                 data_len = size - copied;
1511                 if (data_len > lp->mss)
1512                         data_len = lp->mss;
1513 
1514                 BUG_ON(data_len > LDC_LEN);
1515 
1516                 p->env = (data_len |
1517                           (copied == 0 ? LDC_START : 0) |
1518                           (data_len == size - copied ? LDC_STOP : 0));
1519 
1520                 p->seqid = ++seq;
1521 
1522                 ldcdbg(DATA, "SENT DATA [%02x:%02x:%02x:%02x:%08x]\n",
1523                        p->type,
1524                        p->stype,
1525                        p->ctrl,
1526                        p->env,
1527                        p->seqid);
1528 
1529                 memcpy(data, buf, data_len);
1530                 buf += data_len;
1531                 copied += data_len;
1532 
1533                 tail = tx_advance(lp, tail);
1534         }
1535 
1536         err = set_tx_tail(lp, tail);
1537         if (!err) {
1538                 lp->snd_nxt = seq;
1539                 err = size;
1540         }
1541 
1542         return err;
1543 }
1544 
1545 static int rx_bad_seq(struct ldc_channel *lp, struct ldc_packet *p,
1546                       struct ldc_packet *first_frag)
1547 {
1548         int err;
1549 
1550         if (first_frag)
1551                 lp->rcv_nxt = first_frag->seqid - 1;
1552 
1553         err = send_data_nack(lp, p);
1554         if (err)
1555                 return err;
1556 
1557         err = __set_rx_head(lp, lp->rx_tail);
1558         if (err < 0)
1559                 return ldc_abort(lp);
1560 
1561         return 0;
1562 }
1563 
1564 static int data_ack_nack(struct ldc_channel *lp, struct ldc_packet *p)
1565 {
1566         if (p->stype & LDC_ACK) {
1567                 int err = process_data_ack(lp, p);
1568                 if (err)
1569                         return err;
1570         }
1571         if (p->stype & LDC_NACK)
1572                 return ldc_abort(lp);
1573 
1574         return 0;
1575 }
1576 
1577 static int rx_data_wait(struct ldc_channel *lp, unsigned long cur_head)
1578 {
1579         unsigned long dummy;
1580         int limit = 1000;
1581 
1582         ldcdbg(DATA, "DATA WAIT cur_head[%lx] rx_head[%lx] rx_tail[%lx]\n",
1583                cur_head, lp->rx_head, lp->rx_tail);
1584         while (limit-- > 0) {
1585                 unsigned long hv_err;
1586 
1587                 hv_err = sun4v_ldc_rx_get_state(lp->id,
1588                                                 &dummy,
1589                                                 &lp->rx_tail,
1590                                                 &lp->chan_state);
1591                 if (hv_err)
1592                         return ldc_abort(lp);
1593 
1594                 if (lp->chan_state == LDC_CHANNEL_DOWN ||
1595                     lp->chan_state == LDC_CHANNEL_RESETTING)
1596                         return -ECONNRESET;
1597 
1598                 if (cur_head != lp->rx_tail) {
1599                         ldcdbg(DATA, "DATA WAIT DONE "
1600                                "head[%lx] tail[%lx] chan_state[%lx]\n",
1601                                dummy, lp->rx_tail, lp->chan_state);
1602                         return 0;
1603                 }
1604 
1605                 udelay(1);
1606         }
1607         return -EAGAIN;
1608 }
1609 
1610 static int rx_set_head(struct ldc_channel *lp, unsigned long head)
1611 {
1612         int err = __set_rx_head(lp, head);
1613 
1614         if (err < 0)
1615                 return ldc_abort(lp);
1616 
1617         lp->rx_head = head;
1618         return 0;
1619 }
1620 
1621 static void send_data_ack(struct ldc_channel *lp)
1622 {
1623         unsigned long new_tail;
1624         struct ldc_packet *p;
1625 
1626         p = data_get_tx_packet(lp, &new_tail);
1627         if (likely(p)) {
1628                 int err;
1629 
1630                 memset(p, 0, sizeof(*p));
1631                 p->type = LDC_DATA;
1632                 p->stype = LDC_ACK;
1633                 p->ctrl = 0;
1634                 p->seqid = lp->snd_nxt + 1;
1635                 p->u.r.ackid = lp->rcv_nxt;
1636 
1637                 err = send_tx_packet(lp, p, new_tail);
1638                 if (!err)
1639                         lp->snd_nxt++;
1640         }
1641 }
1642 
1643 static int read_nonraw(struct ldc_channel *lp, void *buf, unsigned int size)
1644 {
1645         struct ldc_packet *first_frag;
1646         unsigned long hv_err, new;
1647         int err, copied;
1648 
1649         hv_err = sun4v_ldc_rx_get_state(lp->id,
1650                                         &lp->rx_head,
1651                                         &lp->rx_tail,
1652                                         &lp->chan_state);
1653         if (hv_err)
1654                 return ldc_abort(lp);
1655 
1656         if (lp->chan_state == LDC_CHANNEL_DOWN ||
1657             lp->chan_state == LDC_CHANNEL_RESETTING)
1658                 return -ECONNRESET;
1659 
1660         if (lp->rx_head == lp->rx_tail)
1661                 return 0;
1662 
1663         first_frag = NULL;
1664         copied = err = 0;
1665         new = lp->rx_head;
1666         while (1) {
1667                 struct ldc_packet *p;
1668                 int pkt_len;
1669 
1670                 BUG_ON(new == lp->rx_tail);
1671                 p = lp->rx_base + (new / LDC_PACKET_SIZE);
1672 
1673                 ldcdbg(RX, "RX read pkt[%02x:%02x:%02x:%02x:%08x:%08x] "
1674                        "rcv_nxt[%08x]\n",
1675                        p->type,
1676                        p->stype,
1677                        p->ctrl,
1678                        p->env,
1679                        p->seqid,
1680                        p->u.r.ackid,
1681                        lp->rcv_nxt);
1682 
1683                 if (unlikely(!rx_seq_ok(lp, p->seqid))) {
1684                         err = rx_bad_seq(lp, p, first_frag);
1685                         copied = 0;
1686                         break;
1687                 }
1688 
1689                 if (p->type & LDC_CTRL) {
1690                         err = process_control_frame(lp, p);
1691                         if (err < 0)
1692                                 break;
1693                         err = 0;
1694                 }
1695 
1696                 lp->rcv_nxt = p->seqid;
1697 
1698                 if (!(p->type & LDC_DATA)) {
1699                         new = rx_advance(lp, new);
1700                         goto no_data;
1701                 }
1702                 if (p->stype & (LDC_ACK | LDC_NACK)) {
1703                         err = data_ack_nack(lp, p);
1704                         if (err)
1705                                 break;
1706                 }
1707                 if (!(p->stype & LDC_INFO)) {
1708                         new = rx_advance(lp, new);
1709                         err = rx_set_head(lp, new);
1710                         if (err)
1711                                 break;
1712                         goto no_data;
1713                 }
1714 
1715                 pkt_len = p->env & LDC_LEN;
1716 
1717                 /* Every initial packet starts with the START bit set.
1718                  *
1719                  * Singleton packets will have both START+STOP set.
1720                  *
1721                  * Fragments will have START set in the first frame, STOP
1722                  * set in the last frame, and neither bit set in middle
1723                  * frames of the packet.
1724                  *
1725                  * Therefore if we are at the beginning of a packet and
1726                  * we don't see START, or we are in the middle of a fragmented
1727                  * packet and do see START, we are unsynchronized and should
1728                  * flush the RX queue.
1729                  */
1730                 if ((first_frag == NULL && !(p->env & LDC_START)) ||
1731                     (first_frag != NULL &&  (p->env & LDC_START))) {
1732                         if (!first_frag)
1733                                 new = rx_advance(lp, new);
1734 
1735                         err = rx_set_head(lp, new);
1736                         if (err)
1737                                 break;
1738 
1739                         if (!first_frag)
1740                                 goto no_data;
1741                 }
1742                 if (!first_frag)
1743                         first_frag = p;
1744 
1745                 if (pkt_len > size - copied) {
1746                         /* User didn't give us a big enough buffer,
1747                          * what to do?  This is a pretty serious error.
1748                          *
1749                          * Since we haven't updated the RX ring head to
1750                          * consume any of the packets, signal the error
1751                          * to the user and just leave the RX ring alone.
1752                          *
1753                          * This seems the best behavior because this allows
1754                          * a user of the LDC layer to start with a small
1755                          * RX buffer for ldc_read() calls and use -EMSGSIZE
1756                          * as a cue to enlarge it's read buffer.
1757                          */
1758                         err = -EMSGSIZE;
1759                         break;
1760                 }
1761 
1762                 /* Ok, we are gonna eat this one.  */
1763                 new = rx_advance(lp, new);
1764 
1765                 memcpy(buf,
1766                        (lp->cfg.mode == LDC_MODE_UNRELIABLE ?
1767                         p->u.u_data : p->u.r.r_data), pkt_len);
1768                 buf += pkt_len;
1769                 copied += pkt_len;
1770 
1771                 if (p->env & LDC_STOP)
1772                         break;
1773 
1774 no_data:
1775                 if (new == lp->rx_tail) {
1776                         err = rx_data_wait(lp, new);
1777                         if (err)
1778                                 break;
1779                 }
1780         }
1781 
1782         if (!err)
1783                 err = rx_set_head(lp, new);
1784 
1785         if (err && first_frag)
1786                 lp->rcv_nxt = first_frag->seqid - 1;
1787 
1788         if (!err) {
1789                 err = copied;
1790                 if (err > 0 && lp->cfg.mode != LDC_MODE_UNRELIABLE)
1791                         send_data_ack(lp);
1792         }
1793 
1794         return err;
1795 }
1796 
1797 static const struct ldc_mode_ops nonraw_ops = {
1798         .write          =       write_nonraw,
1799         .read           =       read_nonraw,
1800 };
1801 
1802 static int write_stream(struct ldc_channel *lp, const void *buf,
1803                         unsigned int size)
1804 {
1805         if (size > lp->cfg.mtu)
1806                 size = lp->cfg.mtu;
1807         return write_nonraw(lp, buf, size);
1808 }
1809 
1810 static int read_stream(struct ldc_channel *lp, void *buf, unsigned int size)
1811 {
1812         if (!lp->mssbuf_len) {
1813                 int err = read_nonraw(lp, lp->mssbuf, lp->cfg.mtu);
1814                 if (err < 0)
1815                         return err;
1816 
1817                 lp->mssbuf_len = err;
1818                 lp->mssbuf_off = 0;
1819         }
1820 
1821         if (size > lp->mssbuf_len)
1822                 size = lp->mssbuf_len;
1823         memcpy(buf, lp->mssbuf + lp->mssbuf_off, size);
1824 
1825         lp->mssbuf_off += size;
1826         lp->mssbuf_len -= size;
1827 
1828         return size;
1829 }
1830 
1831 static const struct ldc_mode_ops stream_ops = {
1832         .write          =       write_stream,
1833         .read           =       read_stream,
1834 };
1835 
1836 int ldc_write(struct ldc_channel *lp, const void *buf, unsigned int size)
1837 {
1838         unsigned long flags;
1839         int err;
1840 
1841         if (!buf)
1842                 return -EINVAL;
1843 
1844         if (!size)
1845                 return 0;
1846 
1847         spin_lock_irqsave(&lp->lock, flags);
1848 
1849         if (lp->hs_state != LDC_HS_COMPLETE)
1850                 err = -ENOTCONN;
1851         else
1852                 err = lp->mops->write(lp, buf, size);
1853 
1854         spin_unlock_irqrestore(&lp->lock, flags);
1855 
1856         return err;
1857 }
1858 EXPORT_SYMBOL(ldc_write);
1859 
1860 int ldc_read(struct ldc_channel *lp, void *buf, unsigned int size)
1861 {
1862         unsigned long flags;
1863         int err;
1864 
1865         if (!buf)
1866                 return -EINVAL;
1867 
1868         if (!size)
1869                 return 0;
1870 
1871         spin_lock_irqsave(&lp->lock, flags);
1872 
1873         if (lp->hs_state != LDC_HS_COMPLETE)
1874                 err = -ENOTCONN;
1875         else
1876                 err = lp->mops->read(lp, buf, size);
1877 
1878         spin_unlock_irqrestore(&lp->lock, flags);
1879 
1880         return err;
1881 }
1882 EXPORT_SYMBOL(ldc_read);
1883 
1884 static long arena_alloc(struct ldc_iommu *iommu, unsigned long npages)
1885 {
1886         struct iommu_arena *arena = &iommu->arena;
1887         unsigned long n, start, end, limit;
1888         int pass;
1889 
1890         limit = arena->limit;
1891         start = arena->hint;
1892         pass = 0;
1893 
1894 again:
1895         n = bitmap_find_next_zero_area(arena->map, limit, start, npages, 0);
1896         end = n + npages;
1897         if (unlikely(end >= limit)) {
1898                 if (likely(pass < 1)) {
1899                         limit = start;
1900                         start = 0;
1901                         pass++;
1902                         goto again;
1903                 } else {
1904                         /* Scanned the whole thing, give up. */
1905                         return -1;
1906                 }
1907         }
1908         bitmap_set(arena->map, n, npages);
1909 
1910         arena->hint = end;
1911 
1912         return n;
1913 }
1914 
1915 #define COOKIE_PGSZ_CODE        0xf000000000000000ULL
1916 #define COOKIE_PGSZ_CODE_SHIFT  60ULL
1917 
1918 static u64 pagesize_code(void)
1919 {
1920         switch (PAGE_SIZE) {
1921         default:
1922         case (8ULL * 1024ULL):
1923                 return 0;
1924         case (64ULL * 1024ULL):
1925                 return 1;
1926         case (512ULL * 1024ULL):
1927                 return 2;
1928         case (4ULL * 1024ULL * 1024ULL):
1929                 return 3;
1930         case (32ULL * 1024ULL * 1024ULL):
1931                 return 4;
1932         case (256ULL * 1024ULL * 1024ULL):
1933                 return 5;
1934         }
1935 }
1936 
1937 static u64 make_cookie(u64 index, u64 pgsz_code, u64 page_offset)
1938 {
1939         return ((pgsz_code << COOKIE_PGSZ_CODE_SHIFT) |
1940                 (index << PAGE_SHIFT) |
1941                 page_offset);
1942 }
1943 
1944 static u64 cookie_to_index(u64 cookie, unsigned long *shift)
1945 {
1946         u64 szcode = cookie >> COOKIE_PGSZ_CODE_SHIFT;
1947 
1948         cookie &= ~COOKIE_PGSZ_CODE;
1949 
1950         *shift = szcode * 3;
1951 
1952         return (cookie >> (13ULL + (szcode * 3ULL)));
1953 }
1954 
1955 static struct ldc_mtable_entry *alloc_npages(struct ldc_iommu *iommu,
1956                                              unsigned long npages)
1957 {
1958         long entry;
1959 
1960         entry = arena_alloc(iommu, npages);
1961         if (unlikely(entry < 0))
1962                 return NULL;
1963 
1964         return iommu->page_table + entry;
1965 }
1966 
1967 static u64 perm_to_mte(unsigned int map_perm)
1968 {
1969         u64 mte_base;
1970 
1971         mte_base = pagesize_code();
1972 
1973         if (map_perm & LDC_MAP_SHADOW) {
1974                 if (map_perm & LDC_MAP_R)
1975                         mte_base |= LDC_MTE_COPY_R;
1976                 if (map_perm & LDC_MAP_W)
1977                         mte_base |= LDC_MTE_COPY_W;
1978         }
1979         if (map_perm & LDC_MAP_DIRECT) {
1980                 if (map_perm & LDC_MAP_R)
1981                         mte_base |= LDC_MTE_READ;
1982                 if (map_perm & LDC_MAP_W)
1983                         mte_base |= LDC_MTE_WRITE;
1984                 if (map_perm & LDC_MAP_X)
1985                         mte_base |= LDC_MTE_EXEC;
1986         }
1987         if (map_perm & LDC_MAP_IO) {
1988                 if (map_perm & LDC_MAP_R)
1989                         mte_base |= LDC_MTE_IOMMU_R;
1990                 if (map_perm & LDC_MAP_W)
1991                         mte_base |= LDC_MTE_IOMMU_W;
1992         }
1993 
1994         return mte_base;
1995 }
1996 
1997 static int pages_in_region(unsigned long base, long len)
1998 {
1999         int count = 0;
2000 
2001         do {
2002                 unsigned long new = (base + PAGE_SIZE) & PAGE_MASK;
2003 
2004                 len -= (new - base);
2005                 base = new;
2006                 count++;
2007         } while (len > 0);
2008 
2009         return count;
2010 }
2011 
2012 struct cookie_state {
2013         struct ldc_mtable_entry         *page_table;
2014         struct ldc_trans_cookie         *cookies;
2015         u64                             mte_base;
2016         u64                             prev_cookie;
2017         u32                             pte_idx;
2018         u32                             nc;
2019 };
2020 
2021 static void fill_cookies(struct cookie_state *sp, unsigned long pa,
2022                          unsigned long off, unsigned long len)
2023 {
2024         do {
2025                 unsigned long tlen, new = pa + PAGE_SIZE;
2026                 u64 this_cookie;
2027 
2028                 sp->page_table[sp->pte_idx].mte = sp->mte_base | pa;
2029 
2030                 tlen = PAGE_SIZE;
2031                 if (off)
2032                         tlen = PAGE_SIZE - off;
2033                 if (tlen > len)
2034                         tlen = len;
2035 
2036                 this_cookie = make_cookie(sp->pte_idx,
2037                                           pagesize_code(), off);
2038 
2039                 off = 0;
2040 
2041                 if (this_cookie == sp->prev_cookie) {
2042                         sp->cookies[sp->nc - 1].cookie_size += tlen;
2043                 } else {
2044                         sp->cookies[sp->nc].cookie_addr = this_cookie;
2045                         sp->cookies[sp->nc].cookie_size = tlen;
2046                         sp->nc++;
2047                 }
2048                 sp->prev_cookie = this_cookie + tlen;
2049 
2050                 sp->pte_idx++;
2051 
2052                 len -= tlen;
2053                 pa = new;
2054         } while (len > 0);
2055 }
2056 
2057 static int sg_count_one(struct scatterlist *sg)
2058 {
2059         unsigned long base = page_to_pfn(sg_page(sg)) << PAGE_SHIFT;
2060         long len = sg->length;
2061 
2062         if ((sg->offset | len) & (8UL - 1))
2063                 return -EFAULT;
2064 
2065         return pages_in_region(base + sg->offset, len);
2066 }
2067 
2068 static int sg_count_pages(struct scatterlist *sg, int num_sg)
2069 {
2070         int count;
2071         int i;
2072 
2073         count = 0;
2074         for (i = 0; i < num_sg; i++) {
2075                 int err = sg_count_one(sg + i);
2076                 if (err < 0)
2077                         return err;
2078                 count += err;
2079         }
2080 
2081         return count;
2082 }
2083 
2084 int ldc_map_sg(struct ldc_channel *lp,
2085                struct scatterlist *sg, int num_sg,
2086                struct ldc_trans_cookie *cookies, int ncookies,
2087                unsigned int map_perm)
2088 {
2089         unsigned long i, npages, flags;
2090         struct ldc_mtable_entry *base;
2091         struct cookie_state state;
2092         struct ldc_iommu *iommu;
2093         int err;
2094 
2095         if (map_perm & ~LDC_MAP_ALL)
2096                 return -EINVAL;
2097 
2098         err = sg_count_pages(sg, num_sg);
2099         if (err < 0)
2100                 return err;
2101 
2102         npages = err;
2103         if (err > ncookies)
2104                 return -EMSGSIZE;
2105 
2106         iommu = &lp->iommu;
2107 
2108         spin_lock_irqsave(&iommu->lock, flags);
2109         base = alloc_npages(iommu, npages);
2110         spin_unlock_irqrestore(&iommu->lock, flags);
2111 
2112         if (!base)
2113                 return -ENOMEM;
2114 
2115         state.page_table = iommu->page_table;
2116         state.cookies = cookies;
2117         state.mte_base = perm_to_mte(map_perm);
2118         state.prev_cookie = ~(u64)0;
2119         state.pte_idx = (base - iommu->page_table);
2120         state.nc = 0;
2121 
2122         for (i = 0; i < num_sg; i++)
2123                 fill_cookies(&state, page_to_pfn(sg_page(&sg[i])) << PAGE_SHIFT,
2124                              sg[i].offset, sg[i].length);
2125 
2126         return state.nc;
2127 }
2128 EXPORT_SYMBOL(ldc_map_sg);
2129 
2130 int ldc_map_single(struct ldc_channel *lp,
2131                    void *buf, unsigned int len,
2132                    struct ldc_trans_cookie *cookies, int ncookies,
2133                    unsigned int map_perm)
2134 {
2135         unsigned long npages, pa, flags;
2136         struct ldc_mtable_entry *base;
2137         struct cookie_state state;
2138         struct ldc_iommu *iommu;
2139 
2140         if ((map_perm & ~LDC_MAP_ALL) || (ncookies < 1))
2141                 return -EINVAL;
2142 
2143         pa = __pa(buf);
2144         if ((pa | len) & (8UL - 1))
2145                 return -EFAULT;
2146 
2147         npages = pages_in_region(pa, len);
2148 
2149         iommu = &lp->iommu;
2150 
2151         spin_lock_irqsave(&iommu->lock, flags);
2152         base = alloc_npages(iommu, npages);
2153         spin_unlock_irqrestore(&iommu->lock, flags);
2154 
2155         if (!base)
2156                 return -ENOMEM;
2157 
2158         state.page_table = iommu->page_table;
2159         state.cookies = cookies;
2160         state.mte_base = perm_to_mte(map_perm);
2161         state.prev_cookie = ~(u64)0;
2162         state.pte_idx = (base - iommu->page_table);
2163         state.nc = 0;
2164         fill_cookies(&state, (pa & PAGE_MASK), (pa & ~PAGE_MASK), len);
2165         BUG_ON(state.nc != 1);
2166 
2167         return state.nc;
2168 }
2169 EXPORT_SYMBOL(ldc_map_single);
2170 
2171 static void free_npages(unsigned long id, struct ldc_iommu *iommu,
2172                         u64 cookie, u64 size)
2173 {
2174         struct iommu_arena *arena = &iommu->arena;
2175         unsigned long i, shift, index, npages;
2176         struct ldc_mtable_entry *base;
2177 
2178         npages = PAGE_ALIGN(((cookie & ~PAGE_MASK) + size)) >> PAGE_SHIFT;
2179         index = cookie_to_index(cookie, &shift);
2180         base = iommu->page_table + index;
2181 
2182         BUG_ON(index > arena->limit ||
2183                (index + npages) > arena->limit);
2184 
2185         for (i = 0; i < npages; i++) {
2186                 if (base->cookie)
2187                         sun4v_ldc_revoke(id, cookie + (i << shift),
2188                                          base->cookie);
2189                 base->mte = 0;
2190                 __clear_bit(index + i, arena->map);
2191         }
2192 }
2193 
2194 void ldc_unmap(struct ldc_channel *lp, struct ldc_trans_cookie *cookies,
2195                int ncookies)
2196 {
2197         struct ldc_iommu *iommu = &lp->iommu;
2198         unsigned long flags;
2199         int i;
2200 
2201         spin_lock_irqsave(&iommu->lock, flags);
2202         for (i = 0; i < ncookies; i++) {
2203                 u64 addr = cookies[i].cookie_addr;
2204                 u64 size = cookies[i].cookie_size;
2205 
2206                 free_npages(lp->id, iommu, addr, size);
2207         }
2208         spin_unlock_irqrestore(&iommu->lock, flags);
2209 }
2210 EXPORT_SYMBOL(ldc_unmap);
2211 
2212 int ldc_copy(struct ldc_channel *lp, int copy_dir,
2213              void *buf, unsigned int len, unsigned long offset,
2214              struct ldc_trans_cookie *cookies, int ncookies)
2215 {
2216         unsigned int orig_len;
2217         unsigned long ra;
2218         int i;
2219 
2220         if (copy_dir != LDC_COPY_IN && copy_dir != LDC_COPY_OUT) {
2221                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Bad copy_dir[%d]\n",
2222                        lp->id, copy_dir);
2223                 return -EINVAL;
2224         }
2225 
2226         ra = __pa(buf);
2227         if ((ra | len | offset) & (8UL - 1)) {
2228                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Unaligned buffer "
2229                        "ra[%lx] len[%x] offset[%lx]\n",
2230                        lp->id, ra, len, offset);
2231                 return -EFAULT;
2232         }
2233 
2234         if (lp->hs_state != LDC_HS_COMPLETE ||
2235             (lp->flags & LDC_FLAG_RESET)) {
2236                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Link down hs_state[%x] "
2237                        "flags[%x]\n", lp->id, lp->hs_state, lp->flags);
2238                 return -ECONNRESET;
2239         }
2240 
2241         orig_len = len;
2242         for (i = 0; i < ncookies; i++) {
2243                 unsigned long cookie_raddr = cookies[i].cookie_addr;
2244                 unsigned long this_len = cookies[i].cookie_size;
2245                 unsigned long actual_len;
2246 
2247                 if (unlikely(offset)) {
2248                         unsigned long this_off = offset;
2249 
2250                         if (this_off > this_len)
2251                                 this_off = this_len;
2252 
2253                         offset -= this_off;
2254                         this_len -= this_off;
2255                         if (!this_len)
2256                                 continue;
2257                         cookie_raddr += this_off;
2258                 }
2259 
2260                 if (this_len > len)
2261                         this_len = len;
2262 
2263                 while (1) {
2264                         unsigned long hv_err;
2265 
2266                         hv_err = sun4v_ldc_copy(lp->id, copy_dir,
2267                                                 cookie_raddr, ra,
2268                                                 this_len, &actual_len);
2269                         if (unlikely(hv_err)) {
2270                                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] "
2271                                        "HV error %lu\n",
2272                                        lp->id, hv_err);
2273                                 if (lp->hs_state != LDC_HS_COMPLETE ||
2274                                     (lp->flags & LDC_FLAG_RESET))
2275                                         return -ECONNRESET;
2276                                 else
2277                                         return -EFAULT;
2278                         }
2279 
2280                         cookie_raddr += actual_len;
2281                         ra += actual_len;
2282                         len -= actual_len;
2283                         if (actual_len == this_len)
2284                                 break;
2285 
2286                         this_len -= actual_len;
2287                 }
2288 
2289                 if (!len)
2290                         break;
2291         }
2292 
2293         /* It is caller policy what to do about short copies.
2294          * For example, a networking driver can declare the
2295          * packet a runt and drop it.
2296          */
2297 
2298         return orig_len - len;
2299 }
2300 EXPORT_SYMBOL(ldc_copy);
2301 
2302 void *ldc_alloc_exp_dring(struct ldc_channel *lp, unsigned int len,
2303                           struct ldc_trans_cookie *cookies, int *ncookies,
2304                           unsigned int map_perm)
2305 {
2306         void *buf;
2307         int err;
2308 
2309         if (len & (8UL - 1))
2310                 return ERR_PTR(-EINVAL);
2311 
2312         buf = kzalloc(len, GFP_KERNEL);
2313         if (!buf)
2314                 return ERR_PTR(-ENOMEM);
2315 
2316         err = ldc_map_single(lp, buf, len, cookies, *ncookies, map_perm);
2317         if (err < 0) {
2318                 kfree(buf);
2319                 return ERR_PTR(err);
2320         }
2321         *ncookies = err;
2322 
2323         return buf;
2324 }
2325 EXPORT_SYMBOL(ldc_alloc_exp_dring);
2326 
2327 void ldc_free_exp_dring(struct ldc_channel *lp, void *buf, unsigned int len,
2328                         struct ldc_trans_cookie *cookies, int ncookies)
2329 {
2330         ldc_unmap(lp, cookies, ncookies);
2331         kfree(buf);
2332 }
2333 EXPORT_SYMBOL(ldc_free_exp_dring);
2334 
2335 static int __init ldc_init(void)
2336 {
2337         unsigned long major, minor;
2338         struct mdesc_handle *hp;
2339         const u64 *v;
2340         int err;
2341         u64 mp;
2342 
2343         hp = mdesc_grab();
2344         if (!hp)
2345                 return -ENODEV;
2346 
2347         mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
2348         err = -ENODEV;
2349         if (mp == MDESC_NODE_NULL)
2350                 goto out;
2351 
2352         v = mdesc_get_property(hp, mp, "domaining-enabled", NULL);
2353         if (!v)
2354                 goto out;
2355 
2356         major = 1;
2357         minor = 0;
2358         if (sun4v_hvapi_register(HV_GRP_LDOM, major, &minor)) {
2359                 printk(KERN_INFO PFX "Could not register LDOM hvapi.\n");
2360                 goto out;
2361         }
2362 
2363         printk(KERN_INFO "%s", version);
2364 
2365         if (!*v) {
2366                 printk(KERN_INFO PFX "Domaining disabled.\n");
2367                 goto out;
2368         }
2369         ldom_domaining_enabled = 1;
2370         err = 0;
2371 
2372 out:
2373         mdesc_release(hp);
2374         return err;
2375 }
2376 
2377 core_initcall(ldc_init);
2378 

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