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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[] =
 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 
957         hlist_for_each_entry(lp, &ldc_channel_list, list) {
958                 if (lp->id == id)
959                         return 1;
960         }
961         return 0;
962 }
963 
964 static int alloc_queue(const char *name, unsigned long num_entries,
965                        struct ldc_packet **base, unsigned long *ra)
966 {
967         unsigned long size, order;
968         void *q;
969 
970         size = num_entries * LDC_PACKET_SIZE;
971         order = get_order(size);
972 
973         q = (void *) __get_free_pages(GFP_KERNEL, order);
974         if (!q) {
975                 printk(KERN_ERR PFX "Alloc of %s queue failed with "
976                        "size=%lu order=%lu\n", name, size, order);
977                 return -ENOMEM;
978         }
979 
980         memset(q, 0, PAGE_SIZE << order);
981 
982         *base = q;
983         *ra = __pa(q);
984 
985         return 0;
986 }
987 
988 static void free_queue(unsigned long num_entries, struct ldc_packet *q)
989 {
990         unsigned long size, order;
991 
992         if (!q)
993                 return;
994 
995         size = num_entries * LDC_PACKET_SIZE;
996         order = get_order(size);
997 
998         free_pages((unsigned long)q, order);
999 }
1000 
1001 /* XXX Make this configurable... XXX */
1002 #define LDC_IOTABLE_SIZE        (8 * 1024)
1003 
1004 static int ldc_iommu_init(struct ldc_channel *lp)
1005 {
1006         unsigned long sz, num_tsb_entries, tsbsize, order;
1007         struct ldc_iommu *iommu = &lp->iommu;
1008         struct ldc_mtable_entry *table;
1009         unsigned long hv_err;
1010         int err;
1011 
1012         num_tsb_entries = LDC_IOTABLE_SIZE;
1013         tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
1014 
1015         spin_lock_init(&iommu->lock);
1016 
1017         sz = num_tsb_entries / 8;
1018         sz = (sz + 7UL) & ~7UL;
1019         iommu->arena.map = kzalloc(sz, GFP_KERNEL);
1020         if (!iommu->arena.map) {
1021                 printk(KERN_ERR PFX "Alloc of arena map failed, sz=%lu\n", sz);
1022                 return -ENOMEM;
1023         }
1024 
1025         iommu->arena.limit = num_tsb_entries;
1026 
1027         order = get_order(tsbsize);
1028 
1029         table = (struct ldc_mtable_entry *)
1030                 __get_free_pages(GFP_KERNEL, order);
1031         err = -ENOMEM;
1032         if (!table) {
1033                 printk(KERN_ERR PFX "Alloc of MTE table failed, "
1034                        "size=%lu order=%lu\n", tsbsize, order);
1035                 goto out_free_map;
1036         }
1037 
1038         memset(table, 0, PAGE_SIZE << order);
1039 
1040         iommu->page_table = table;
1041 
1042         hv_err = sun4v_ldc_set_map_table(lp->id, __pa(table),
1043                                          num_tsb_entries);
1044         err = -EINVAL;
1045         if (hv_err)
1046                 goto out_free_table;
1047 
1048         return 0;
1049 
1050 out_free_table:
1051         free_pages((unsigned long) table, order);
1052         iommu->page_table = NULL;
1053 
1054 out_free_map:
1055         kfree(iommu->arena.map);
1056         iommu->arena.map = NULL;
1057 
1058         return err;
1059 }
1060 
1061 static void ldc_iommu_release(struct ldc_channel *lp)
1062 {
1063         struct ldc_iommu *iommu = &lp->iommu;
1064         unsigned long num_tsb_entries, tsbsize, order;
1065 
1066         (void) sun4v_ldc_set_map_table(lp->id, 0, 0);
1067 
1068         num_tsb_entries = iommu->arena.limit;
1069         tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
1070         order = get_order(tsbsize);
1071 
1072         free_pages((unsigned long) iommu->page_table, order);
1073         iommu->page_table = NULL;
1074 
1075         kfree(iommu->arena.map);
1076         iommu->arena.map = NULL;
1077 }
1078 
1079 struct ldc_channel *ldc_alloc(unsigned long id,
1080                               const struct ldc_channel_config *cfgp,
1081                               void *event_arg)
1082 {
1083         struct ldc_channel *lp;
1084         const struct ldc_mode_ops *mops;
1085         unsigned long dummy1, dummy2, hv_err;
1086         u8 mss, *mssbuf;
1087         int err;
1088 
1089         err = -ENODEV;
1090         if (!ldom_domaining_enabled)
1091                 goto out_err;
1092 
1093         err = -EINVAL;
1094         if (!cfgp)
1095                 goto out_err;
1096 
1097         switch (cfgp->mode) {
1098         case LDC_MODE_RAW:
1099                 mops = &raw_ops;
1100                 mss = LDC_PACKET_SIZE;
1101                 break;
1102 
1103         case LDC_MODE_UNRELIABLE:
1104                 mops = &nonraw_ops;
1105                 mss = LDC_PACKET_SIZE - 8;
1106                 break;
1107 
1108         case LDC_MODE_STREAM:
1109                 mops = &stream_ops;
1110                 mss = LDC_PACKET_SIZE - 8 - 8;
1111                 break;
1112 
1113         default:
1114                 goto out_err;
1115         }
1116 
1117         if (!cfgp->event || !event_arg || !cfgp->rx_irq || !cfgp->tx_irq)
1118                 goto out_err;
1119 
1120         hv_err = sun4v_ldc_tx_qinfo(id, &dummy1, &dummy2);
1121         err = -ENODEV;
1122         if (hv_err == HV_ECHANNEL)
1123                 goto out_err;
1124 
1125         err = -EEXIST;
1126         if (__ldc_channel_exists(id))
1127                 goto out_err;
1128 
1129         mssbuf = NULL;
1130 
1131         lp = kzalloc(sizeof(*lp), GFP_KERNEL);
1132         err = -ENOMEM;
1133         if (!lp)
1134                 goto out_err;
1135 
1136         spin_lock_init(&lp->lock);
1137 
1138         lp->id = id;
1139 
1140         err = ldc_iommu_init(lp);
1141         if (err)
1142                 goto out_free_ldc;
1143 
1144         lp->mops = mops;
1145         lp->mss = mss;
1146 
1147         lp->cfg = *cfgp;
1148         if (!lp->cfg.mtu)
1149                 lp->cfg.mtu = LDC_DEFAULT_MTU;
1150 
1151         if (lp->cfg.mode == LDC_MODE_STREAM) {
1152                 mssbuf = kzalloc(lp->cfg.mtu, GFP_KERNEL);
1153                 if (!mssbuf) {
1154                         err = -ENOMEM;
1155                         goto out_free_iommu;
1156                 }
1157                 lp->mssbuf = mssbuf;
1158         }
1159 
1160         lp->event_arg = event_arg;
1161 
1162         /* XXX allow setting via ldc_channel_config to override defaults
1163          * XXX or use some formula based upon mtu
1164          */
1165         lp->tx_num_entries = LDC_DEFAULT_NUM_ENTRIES;
1166         lp->rx_num_entries = LDC_DEFAULT_NUM_ENTRIES;
1167 
1168         err = alloc_queue("TX", lp->tx_num_entries,
1169                           &lp->tx_base, &lp->tx_ra);
1170         if (err)
1171                 goto out_free_mssbuf;
1172 
1173         err = alloc_queue("RX", lp->rx_num_entries,
1174                           &lp->rx_base, &lp->rx_ra);
1175         if (err)
1176                 goto out_free_txq;
1177 
1178         lp->flags |= LDC_FLAG_ALLOCED_QUEUES;
1179 
1180         lp->hs_state = LDC_HS_CLOSED;
1181         ldc_set_state(lp, LDC_STATE_INIT);
1182 
1183         INIT_HLIST_NODE(&lp->list);
1184         hlist_add_head(&lp->list, &ldc_channel_list);
1185 
1186         INIT_HLIST_HEAD(&lp->mh_list);
1187 
1188         return lp;
1189 
1190 out_free_txq:
1191         free_queue(lp->tx_num_entries, lp->tx_base);
1192 
1193 out_free_mssbuf:
1194         kfree(mssbuf);
1195 
1196 out_free_iommu:
1197         ldc_iommu_release(lp);
1198 
1199 out_free_ldc:
1200         kfree(lp);
1201 
1202 out_err:
1203         return ERR_PTR(err);
1204 }
1205 EXPORT_SYMBOL(ldc_alloc);
1206 
1207 void ldc_free(struct ldc_channel *lp)
1208 {
1209         if (lp->flags & LDC_FLAG_REGISTERED_IRQS) {
1210                 free_irq(lp->cfg.rx_irq, lp);
1211                 free_irq(lp->cfg.tx_irq, lp);
1212         }
1213 
1214         if (lp->flags & LDC_FLAG_REGISTERED_QUEUES) {
1215                 sun4v_ldc_tx_qconf(lp->id, 0, 0);
1216                 sun4v_ldc_rx_qconf(lp->id, 0, 0);
1217                 lp->flags &= ~LDC_FLAG_REGISTERED_QUEUES;
1218         }
1219         if (lp->flags & LDC_FLAG_ALLOCED_QUEUES) {
1220                 free_queue(lp->tx_num_entries, lp->tx_base);
1221                 free_queue(lp->rx_num_entries, lp->rx_base);
1222                 lp->flags &= ~LDC_FLAG_ALLOCED_QUEUES;
1223         }
1224 
1225         hlist_del(&lp->list);
1226 
1227         kfree(lp->mssbuf);
1228 
1229         ldc_iommu_release(lp);
1230 
1231         kfree(lp);
1232 }
1233 EXPORT_SYMBOL(ldc_free);
1234 
1235 /* Bind the channel.  This registers the LDC queues with
1236  * the hypervisor and puts the channel into a pseudo-listening
1237  * state.  This does not initiate a handshake, ldc_connect() does
1238  * that.
1239  */
1240 int ldc_bind(struct ldc_channel *lp, const char *name)
1241 {
1242         unsigned long hv_err, flags;
1243         int err = -EINVAL;
1244 
1245         if (!name ||
1246             (lp->state != LDC_STATE_INIT))
1247                 return -EINVAL;
1248 
1249         snprintf(lp->rx_irq_name, LDC_IRQ_NAME_MAX, "%s RX", name);
1250         snprintf(lp->tx_irq_name, LDC_IRQ_NAME_MAX, "%s TX", name);
1251 
1252         err = request_irq(lp->cfg.rx_irq, ldc_rx, IRQF_DISABLED,
1253                           lp->rx_irq_name, lp);
1254         if (err)
1255                 return err;
1256 
1257         err = request_irq(lp->cfg.tx_irq, ldc_tx, IRQF_DISABLED,
1258                           lp->tx_irq_name, lp);
1259         if (err) {
1260                 free_irq(lp->cfg.rx_irq, lp);
1261                 return err;
1262         }
1263 
1264 
1265         spin_lock_irqsave(&lp->lock, flags);
1266 
1267         enable_irq(lp->cfg.rx_irq);
1268         enable_irq(lp->cfg.tx_irq);
1269 
1270         lp->flags |= LDC_FLAG_REGISTERED_IRQS;
1271 
1272         err = -ENODEV;
1273         hv_err = sun4v_ldc_tx_qconf(lp->id, 0, 0);
1274         if (hv_err)
1275                 goto out_free_irqs;
1276 
1277         hv_err = sun4v_ldc_tx_qconf(lp->id, lp->tx_ra, lp->tx_num_entries);
1278         if (hv_err)
1279                 goto out_free_irqs;
1280 
1281         hv_err = sun4v_ldc_rx_qconf(lp->id, 0, 0);
1282         if (hv_err)
1283                 goto out_unmap_tx;
1284 
1285         hv_err = sun4v_ldc_rx_qconf(lp->id, lp->rx_ra, lp->rx_num_entries);
1286         if (hv_err)
1287                 goto out_unmap_tx;
1288 
1289         lp->flags |= LDC_FLAG_REGISTERED_QUEUES;
1290 
1291         hv_err = sun4v_ldc_tx_get_state(lp->id,
1292                                         &lp->tx_head,
1293                                         &lp->tx_tail,
1294                                         &lp->chan_state);
1295         err = -EBUSY;
1296         if (hv_err)
1297                 goto out_unmap_rx;
1298 
1299         lp->tx_acked = lp->tx_head;
1300 
1301         lp->hs_state = LDC_HS_OPEN;
1302         ldc_set_state(lp, LDC_STATE_BOUND);
1303 
1304         spin_unlock_irqrestore(&lp->lock, flags);
1305 
1306         return 0;
1307 
1308 out_unmap_rx:
1309         lp->flags &= ~LDC_FLAG_REGISTERED_QUEUES;
1310         sun4v_ldc_rx_qconf(lp->id, 0, 0);
1311 
1312 out_unmap_tx:
1313         sun4v_ldc_tx_qconf(lp->id, 0, 0);
1314 
1315 out_free_irqs:
1316         lp->flags &= ~LDC_FLAG_REGISTERED_IRQS;
1317         free_irq(lp->cfg.tx_irq, lp);
1318         free_irq(lp->cfg.rx_irq, lp);
1319 
1320         spin_unlock_irqrestore(&lp->lock, flags);
1321 
1322         return err;
1323 }
1324 EXPORT_SYMBOL(ldc_bind);
1325 
1326 int ldc_connect(struct ldc_channel *lp)
1327 {
1328         unsigned long flags;
1329         int err;
1330 
1331         if (lp->cfg.mode == LDC_MODE_RAW)
1332                 return -EINVAL;
1333 
1334         spin_lock_irqsave(&lp->lock, flags);
1335 
1336         if (!(lp->flags & LDC_FLAG_ALLOCED_QUEUES) ||
1337             !(lp->flags & LDC_FLAG_REGISTERED_QUEUES) ||
1338             lp->hs_state != LDC_HS_OPEN)
1339                 err = -EINVAL;
1340         else
1341                 err = start_handshake(lp);
1342 
1343         spin_unlock_irqrestore(&lp->lock, flags);
1344 
1345         return err;
1346 }
1347 EXPORT_SYMBOL(ldc_connect);
1348 
1349 int ldc_disconnect(struct ldc_channel *lp)
1350 {
1351         unsigned long hv_err, flags;
1352         int err;
1353 
1354         if (lp->cfg.mode == LDC_MODE_RAW)
1355                 return -EINVAL;
1356 
1357         if (!(lp->flags & LDC_FLAG_ALLOCED_QUEUES) ||
1358             !(lp->flags & LDC_FLAG_REGISTERED_QUEUES))
1359                 return -EINVAL;
1360 
1361         spin_lock_irqsave(&lp->lock, flags);
1362 
1363         err = -ENODEV;
1364         hv_err = sun4v_ldc_tx_qconf(lp->id, 0, 0);
1365         if (hv_err)
1366                 goto out_err;
1367 
1368         hv_err = sun4v_ldc_tx_qconf(lp->id, lp->tx_ra, lp->tx_num_entries);
1369         if (hv_err)
1370                 goto out_err;
1371 
1372         hv_err = sun4v_ldc_rx_qconf(lp->id, 0, 0);
1373         if (hv_err)
1374                 goto out_err;
1375 
1376         hv_err = sun4v_ldc_rx_qconf(lp->id, lp->rx_ra, lp->rx_num_entries);
1377         if (hv_err)
1378                 goto out_err;
1379 
1380         ldc_set_state(lp, LDC_STATE_BOUND);
1381         lp->hs_state = LDC_HS_OPEN;
1382         lp->flags |= LDC_FLAG_RESET;
1383 
1384         spin_unlock_irqrestore(&lp->lock, flags);
1385 
1386         return 0;
1387 
1388 out_err:
1389         sun4v_ldc_tx_qconf(lp->id, 0, 0);
1390         sun4v_ldc_rx_qconf(lp->id, 0, 0);
1391         free_irq(lp->cfg.tx_irq, lp);
1392         free_irq(lp->cfg.rx_irq, lp);
1393         lp->flags &= ~(LDC_FLAG_REGISTERED_IRQS |
1394                        LDC_FLAG_REGISTERED_QUEUES);
1395         ldc_set_state(lp, LDC_STATE_INIT);
1396 
1397         spin_unlock_irqrestore(&lp->lock, flags);
1398 
1399         return err;
1400 }
1401 EXPORT_SYMBOL(ldc_disconnect);
1402 
1403 int ldc_state(struct ldc_channel *lp)
1404 {
1405         return lp->state;
1406 }
1407 EXPORT_SYMBOL(ldc_state);
1408 
1409 static int write_raw(struct ldc_channel *lp, const void *buf, unsigned int size)
1410 {
1411         struct ldc_packet *p;
1412         unsigned long new_tail;
1413         int err;
1414 
1415         if (size > LDC_PACKET_SIZE)
1416                 return -EMSGSIZE;
1417 
1418         p = data_get_tx_packet(lp, &new_tail);
1419         if (!p)
1420                 return -EAGAIN;
1421 
1422         memcpy(p, buf, size);
1423 
1424         err = send_tx_packet(lp, p, new_tail);
1425         if (!err)
1426                 err = size;
1427 
1428         return err;
1429 }
1430 
1431 static int read_raw(struct ldc_channel *lp, void *buf, unsigned int size)
1432 {
1433         struct ldc_packet *p;
1434         unsigned long hv_err, new;
1435         int err;
1436 
1437         if (size < LDC_PACKET_SIZE)
1438                 return -EINVAL;
1439 
1440         hv_err = sun4v_ldc_rx_get_state(lp->id,
1441                                         &lp->rx_head,
1442                                         &lp->rx_tail,
1443                                         &lp->chan_state);
1444         if (hv_err)
1445                 return ldc_abort(lp);
1446 
1447         if (lp->chan_state == LDC_CHANNEL_DOWN ||
1448             lp->chan_state == LDC_CHANNEL_RESETTING)
1449                 return -ECONNRESET;
1450 
1451         if (lp->rx_head == lp->rx_tail)
1452                 return 0;
1453 
1454         p = lp->rx_base + (lp->rx_head / LDC_PACKET_SIZE);
1455         memcpy(buf, p, LDC_PACKET_SIZE);
1456 
1457         new = rx_advance(lp, lp->rx_head);
1458         lp->rx_head = new;
1459 
1460         err = __set_rx_head(lp, new);
1461         if (err < 0)
1462                 err = -ECONNRESET;
1463         else
1464                 err = LDC_PACKET_SIZE;
1465 
1466         return err;
1467 }
1468 
1469 static const struct ldc_mode_ops raw_ops = {
1470         .write          =       write_raw,
1471         .read           =       read_raw,
1472 };
1473 
1474 static int write_nonraw(struct ldc_channel *lp, const void *buf,
1475                         unsigned int size)
1476 {
1477         unsigned long hv_err, tail;
1478         unsigned int copied;
1479         u32 seq;
1480         int err;
1481 
1482         hv_err = sun4v_ldc_tx_get_state(lp->id, &lp->tx_head, &lp->tx_tail,
1483                                         &lp->chan_state);
1484         if (unlikely(hv_err))
1485                 return -EBUSY;
1486 
1487         if (unlikely(lp->chan_state != LDC_CHANNEL_UP))
1488                 return ldc_abort(lp);
1489 
1490         if (!tx_has_space_for(lp, size))
1491                 return -EAGAIN;
1492 
1493         seq = lp->snd_nxt;
1494         copied = 0;
1495         tail = lp->tx_tail;
1496         while (copied < size) {
1497                 struct ldc_packet *p = lp->tx_base + (tail / LDC_PACKET_SIZE);
1498                 u8 *data = ((lp->cfg.mode == LDC_MODE_UNRELIABLE) ?
1499                             p->u.u_data :
1500                             p->u.r.r_data);
1501                 int data_len;
1502 
1503                 p->type = LDC_DATA;
1504                 p->stype = LDC_INFO;
1505                 p->ctrl = 0;
1506 
1507                 data_len = size - copied;
1508                 if (data_len > lp->mss)
1509                         data_len = lp->mss;
1510 
1511                 BUG_ON(data_len > LDC_LEN);
1512 
1513                 p->env = (data_len |
1514                           (copied == 0 ? LDC_START : 0) |
1515                           (data_len == size - copied ? LDC_STOP : 0));
1516 
1517                 p->seqid = ++seq;
1518 
1519                 ldcdbg(DATA, "SENT DATA [%02x:%02x:%02x:%02x:%08x]\n",
1520                        p->type,
1521                        p->stype,
1522                        p->ctrl,
1523                        p->env,
1524                        p->seqid);
1525 
1526                 memcpy(data, buf, data_len);
1527                 buf += data_len;
1528                 copied += data_len;
1529 
1530                 tail = tx_advance(lp, tail);
1531         }
1532 
1533         err = set_tx_tail(lp, tail);
1534         if (!err) {
1535                 lp->snd_nxt = seq;
1536                 err = size;
1537         }
1538 
1539         return err;
1540 }
1541 
1542 static int rx_bad_seq(struct ldc_channel *lp, struct ldc_packet *p,
1543                       struct ldc_packet *first_frag)
1544 {
1545         int err;
1546 
1547         if (first_frag)
1548                 lp->rcv_nxt = first_frag->seqid - 1;
1549 
1550         err = send_data_nack(lp, p);
1551         if (err)
1552                 return err;
1553 
1554         err = __set_rx_head(lp, lp->rx_tail);
1555         if (err < 0)
1556                 return ldc_abort(lp);
1557 
1558         return 0;
1559 }
1560 
1561 static int data_ack_nack(struct ldc_channel *lp, struct ldc_packet *p)
1562 {
1563         if (p->stype & LDC_ACK) {
1564                 int err = process_data_ack(lp, p);
1565                 if (err)
1566                         return err;
1567         }
1568         if (p->stype & LDC_NACK)
1569                 return ldc_abort(lp);
1570 
1571         return 0;
1572 }
1573 
1574 static int rx_data_wait(struct ldc_channel *lp, unsigned long cur_head)
1575 {
1576         unsigned long dummy;
1577         int limit = 1000;
1578 
1579         ldcdbg(DATA, "DATA WAIT cur_head[%lx] rx_head[%lx] rx_tail[%lx]\n",
1580                cur_head, lp->rx_head, lp->rx_tail);
1581         while (limit-- > 0) {
1582                 unsigned long hv_err;
1583 
1584                 hv_err = sun4v_ldc_rx_get_state(lp->id,
1585                                                 &dummy,
1586                                                 &lp->rx_tail,
1587                                                 &lp->chan_state);
1588                 if (hv_err)
1589                         return ldc_abort(lp);
1590 
1591                 if (lp->chan_state == LDC_CHANNEL_DOWN ||
1592                     lp->chan_state == LDC_CHANNEL_RESETTING)
1593                         return -ECONNRESET;
1594 
1595                 if (cur_head != lp->rx_tail) {
1596                         ldcdbg(DATA, "DATA WAIT DONE "
1597                                "head[%lx] tail[%lx] chan_state[%lx]\n",
1598                                dummy, lp->rx_tail, lp->chan_state);
1599                         return 0;
1600                 }
1601 
1602                 udelay(1);
1603         }
1604         return -EAGAIN;
1605 }
1606 
1607 static int rx_set_head(struct ldc_channel *lp, unsigned long head)
1608 {
1609         int err = __set_rx_head(lp, head);
1610 
1611         if (err < 0)
1612                 return ldc_abort(lp);
1613 
1614         lp->rx_head = head;
1615         return 0;
1616 }
1617 
1618 static void send_data_ack(struct ldc_channel *lp)
1619 {
1620         unsigned long new_tail;
1621         struct ldc_packet *p;
1622 
1623         p = data_get_tx_packet(lp, &new_tail);
1624         if (likely(p)) {
1625                 int err;
1626 
1627                 memset(p, 0, sizeof(*p));
1628                 p->type = LDC_DATA;
1629                 p->stype = LDC_ACK;
1630                 p->ctrl = 0;
1631                 p->seqid = lp->snd_nxt + 1;
1632                 p->u.r.ackid = lp->rcv_nxt;
1633 
1634                 err = send_tx_packet(lp, p, new_tail);
1635                 if (!err)
1636                         lp->snd_nxt++;
1637         }
1638 }
1639 
1640 static int read_nonraw(struct ldc_channel *lp, void *buf, unsigned int size)
1641 {
1642         struct ldc_packet *first_frag;
1643         unsigned long hv_err, new;
1644         int err, copied;
1645 
1646         hv_err = sun4v_ldc_rx_get_state(lp->id,
1647                                         &lp->rx_head,
1648                                         &lp->rx_tail,
1649                                         &lp->chan_state);
1650         if (hv_err)
1651                 return ldc_abort(lp);
1652 
1653         if (lp->chan_state == LDC_CHANNEL_DOWN ||
1654             lp->chan_state == LDC_CHANNEL_RESETTING)
1655                 return -ECONNRESET;
1656 
1657         if (lp->rx_head == lp->rx_tail)
1658                 return 0;
1659 
1660         first_frag = NULL;
1661         copied = err = 0;
1662         new = lp->rx_head;
1663         while (1) {
1664                 struct ldc_packet *p;
1665                 int pkt_len;
1666 
1667                 BUG_ON(new == lp->rx_tail);
1668                 p = lp->rx_base + (new / LDC_PACKET_SIZE);
1669 
1670                 ldcdbg(RX, "RX read pkt[%02x:%02x:%02x:%02x:%08x:%08x] "
1671                        "rcv_nxt[%08x]\n",
1672                        p->type,
1673                        p->stype,
1674                        p->ctrl,
1675                        p->env,
1676                        p->seqid,
1677                        p->u.r.ackid,
1678                        lp->rcv_nxt);
1679 
1680                 if (unlikely(!rx_seq_ok(lp, p->seqid))) {
1681                         err = rx_bad_seq(lp, p, first_frag);
1682                         copied = 0;
1683                         break;
1684                 }
1685 
1686                 if (p->type & LDC_CTRL) {
1687                         err = process_control_frame(lp, p);
1688                         if (err < 0)
1689                                 break;
1690                         err = 0;
1691                 }
1692 
1693                 lp->rcv_nxt = p->seqid;
1694 
1695                 if (!(p->type & LDC_DATA)) {
1696                         new = rx_advance(lp, new);
1697                         goto no_data;
1698                 }
1699                 if (p->stype & (LDC_ACK | LDC_NACK)) {
1700                         err = data_ack_nack(lp, p);
1701                         if (err)
1702                                 break;
1703                 }
1704                 if (!(p->stype & LDC_INFO)) {
1705                         new = rx_advance(lp, new);
1706                         err = rx_set_head(lp, new);
1707                         if (err)
1708                                 break;
1709                         goto no_data;
1710                 }
1711 
1712                 pkt_len = p->env & LDC_LEN;
1713 
1714                 /* Every initial packet starts with the START bit set.
1715                  *
1716                  * Singleton packets will have both START+STOP set.
1717                  *
1718                  * Fragments will have START set in the first frame, STOP
1719                  * set in the last frame, and neither bit set in middle
1720                  * frames of the packet.
1721                  *
1722                  * Therefore if we are at the beginning of a packet and
1723                  * we don't see START, or we are in the middle of a fragmented
1724                  * packet and do see START, we are unsynchronized and should
1725                  * flush the RX queue.
1726                  */
1727                 if ((first_frag == NULL && !(p->env & LDC_START)) ||
1728                     (first_frag != NULL &&  (p->env & LDC_START))) {
1729                         if (!first_frag)
1730                                 new = rx_advance(lp, new);
1731 
1732                         err = rx_set_head(lp, new);
1733                         if (err)
1734                                 break;
1735 
1736                         if (!first_frag)
1737                                 goto no_data;
1738                 }
1739                 if (!first_frag)
1740                         first_frag = p;
1741 
1742                 if (pkt_len > size - copied) {
1743                         /* User didn't give us a big enough buffer,
1744                          * what to do?  This is a pretty serious error.
1745                          *
1746                          * Since we haven't updated the RX ring head to
1747                          * consume any of the packets, signal the error
1748                          * to the user and just leave the RX ring alone.
1749                          *
1750                          * This seems the best behavior because this allows
1751                          * a user of the LDC layer to start with a small
1752                          * RX buffer for ldc_read() calls and use -EMSGSIZE
1753                          * as a cue to enlarge it's read buffer.
1754                          */
1755                         err = -EMSGSIZE;
1756                         break;
1757                 }
1758 
1759                 /* Ok, we are gonna eat this one.  */
1760                 new = rx_advance(lp, new);
1761 
1762                 memcpy(buf,
1763                        (lp->cfg.mode == LDC_MODE_UNRELIABLE ?
1764                         p->u.u_data : p->u.r.r_data), pkt_len);
1765                 buf += pkt_len;
1766                 copied += pkt_len;
1767 
1768                 if (p->env & LDC_STOP)
1769                         break;
1770 
1771 no_data:
1772                 if (new == lp->rx_tail) {
1773                         err = rx_data_wait(lp, new);
1774                         if (err)
1775                                 break;
1776                 }
1777         }
1778 
1779         if (!err)
1780                 err = rx_set_head(lp, new);
1781 
1782         if (err && first_frag)
1783                 lp->rcv_nxt = first_frag->seqid - 1;
1784 
1785         if (!err) {
1786                 err = copied;
1787                 if (err > 0 && lp->cfg.mode != LDC_MODE_UNRELIABLE)
1788                         send_data_ack(lp);
1789         }
1790 
1791         return err;
1792 }
1793 
1794 static const struct ldc_mode_ops nonraw_ops = {
1795         .write          =       write_nonraw,
1796         .read           =       read_nonraw,
1797 };
1798 
1799 static int write_stream(struct ldc_channel *lp, const void *buf,
1800                         unsigned int size)
1801 {
1802         if (size > lp->cfg.mtu)
1803                 size = lp->cfg.mtu;
1804         return write_nonraw(lp, buf, size);
1805 }
1806 
1807 static int read_stream(struct ldc_channel *lp, void *buf, unsigned int size)
1808 {
1809         if (!lp->mssbuf_len) {
1810                 int err = read_nonraw(lp, lp->mssbuf, lp->cfg.mtu);
1811                 if (err < 0)
1812                         return err;
1813 
1814                 lp->mssbuf_len = err;
1815                 lp->mssbuf_off = 0;
1816         }
1817 
1818         if (size > lp->mssbuf_len)
1819                 size = lp->mssbuf_len;
1820         memcpy(buf, lp->mssbuf + lp->mssbuf_off, size);
1821 
1822         lp->mssbuf_off += size;
1823         lp->mssbuf_len -= size;
1824 
1825         return size;
1826 }
1827 
1828 static const struct ldc_mode_ops stream_ops = {
1829         .write          =       write_stream,
1830         .read           =       read_stream,
1831 };
1832 
1833 int ldc_write(struct ldc_channel *lp, const void *buf, unsigned int size)
1834 {
1835         unsigned long flags;
1836         int err;
1837 
1838         if (!buf)
1839                 return -EINVAL;
1840 
1841         if (!size)
1842                 return 0;
1843 
1844         spin_lock_irqsave(&lp->lock, flags);
1845 
1846         if (lp->hs_state != LDC_HS_COMPLETE)
1847                 err = -ENOTCONN;
1848         else
1849                 err = lp->mops->write(lp, buf, size);
1850 
1851         spin_unlock_irqrestore(&lp->lock, flags);
1852 
1853         return err;
1854 }
1855 EXPORT_SYMBOL(ldc_write);
1856 
1857 int ldc_read(struct ldc_channel *lp, void *buf, unsigned int size)
1858 {
1859         unsigned long flags;
1860         int err;
1861 
1862         if (!buf)
1863                 return -EINVAL;
1864 
1865         if (!size)
1866                 return 0;
1867 
1868         spin_lock_irqsave(&lp->lock, flags);
1869 
1870         if (lp->hs_state != LDC_HS_COMPLETE)
1871                 err = -ENOTCONN;
1872         else
1873                 err = lp->mops->read(lp, buf, size);
1874 
1875         spin_unlock_irqrestore(&lp->lock, flags);
1876 
1877         return err;
1878 }
1879 EXPORT_SYMBOL(ldc_read);
1880 
1881 static long arena_alloc(struct ldc_iommu *iommu, unsigned long npages)
1882 {
1883         struct iommu_arena *arena = &iommu->arena;
1884         unsigned long n, start, end, limit;
1885         int pass;
1886 
1887         limit = arena->limit;
1888         start = arena->hint;
1889         pass = 0;
1890 
1891 again:
1892         n = bitmap_find_next_zero_area(arena->map, limit, start, npages, 0);
1893         end = n + npages;
1894         if (unlikely(end >= limit)) {
1895                 if (likely(pass < 1)) {
1896                         limit = start;
1897                         start = 0;
1898                         pass++;
1899                         goto again;
1900                 } else {
1901                         /* Scanned the whole thing, give up. */
1902                         return -1;
1903                 }
1904         }
1905         bitmap_set(arena->map, n, npages);
1906 
1907         arena->hint = end;
1908 
1909         return n;
1910 }
1911 
1912 #define COOKIE_PGSZ_CODE        0xf000000000000000ULL
1913 #define COOKIE_PGSZ_CODE_SHIFT  60ULL
1914 
1915 static u64 pagesize_code(void)
1916 {
1917         switch (PAGE_SIZE) {
1918         default:
1919         case (8ULL * 1024ULL):
1920                 return 0;
1921         case (64ULL * 1024ULL):
1922                 return 1;
1923         case (512ULL * 1024ULL):
1924                 return 2;
1925         case (4ULL * 1024ULL * 1024ULL):
1926                 return 3;
1927         case (32ULL * 1024ULL * 1024ULL):
1928                 return 4;
1929         case (256ULL * 1024ULL * 1024ULL):
1930                 return 5;
1931         }
1932 }
1933 
1934 static u64 make_cookie(u64 index, u64 pgsz_code, u64 page_offset)
1935 {
1936         return ((pgsz_code << COOKIE_PGSZ_CODE_SHIFT) |
1937                 (index << PAGE_SHIFT) |
1938                 page_offset);
1939 }
1940 
1941 static u64 cookie_to_index(u64 cookie, unsigned long *shift)
1942 {
1943         u64 szcode = cookie >> COOKIE_PGSZ_CODE_SHIFT;
1944 
1945         cookie &= ~COOKIE_PGSZ_CODE;
1946 
1947         *shift = szcode * 3;
1948 
1949         return (cookie >> (13ULL + (szcode * 3ULL)));
1950 }
1951 
1952 static struct ldc_mtable_entry *alloc_npages(struct ldc_iommu *iommu,
1953                                              unsigned long npages)
1954 {
1955         long entry;
1956 
1957         entry = arena_alloc(iommu, npages);
1958         if (unlikely(entry < 0))
1959                 return NULL;
1960 
1961         return iommu->page_table + entry;
1962 }
1963 
1964 static u64 perm_to_mte(unsigned int map_perm)
1965 {
1966         u64 mte_base;
1967 
1968         mte_base = pagesize_code();
1969 
1970         if (map_perm & LDC_MAP_SHADOW) {
1971                 if (map_perm & LDC_MAP_R)
1972                         mte_base |= LDC_MTE_COPY_R;
1973                 if (map_perm & LDC_MAP_W)
1974                         mte_base |= LDC_MTE_COPY_W;
1975         }
1976         if (map_perm & LDC_MAP_DIRECT) {
1977                 if (map_perm & LDC_MAP_R)
1978                         mte_base |= LDC_MTE_READ;
1979                 if (map_perm & LDC_MAP_W)
1980                         mte_base |= LDC_MTE_WRITE;
1981                 if (map_perm & LDC_MAP_X)
1982                         mte_base |= LDC_MTE_EXEC;
1983         }
1984         if (map_perm & LDC_MAP_IO) {
1985                 if (map_perm & LDC_MAP_R)
1986                         mte_base |= LDC_MTE_IOMMU_R;
1987                 if (map_perm & LDC_MAP_W)
1988                         mte_base |= LDC_MTE_IOMMU_W;
1989         }
1990 
1991         return mte_base;
1992 }
1993 
1994 static int pages_in_region(unsigned long base, long len)
1995 {
1996         int count = 0;
1997 
1998         do {
1999                 unsigned long new = (base + PAGE_SIZE) & PAGE_MASK;
2000 
2001                 len -= (new - base);
2002                 base = new;
2003                 count++;
2004         } while (len > 0);
2005 
2006         return count;
2007 }
2008 
2009 struct cookie_state {
2010         struct ldc_mtable_entry         *page_table;
2011         struct ldc_trans_cookie         *cookies;
2012         u64                             mte_base;
2013         u64                             prev_cookie;
2014         u32                             pte_idx;
2015         u32                             nc;
2016 };
2017 
2018 static void fill_cookies(struct cookie_state *sp, unsigned long pa,
2019                          unsigned long off, unsigned long len)
2020 {
2021         do {
2022                 unsigned long tlen, new = pa + PAGE_SIZE;
2023                 u64 this_cookie;
2024 
2025                 sp->page_table[sp->pte_idx].mte = sp->mte_base | pa;
2026 
2027                 tlen = PAGE_SIZE;
2028                 if (off)
2029                         tlen = PAGE_SIZE - off;
2030                 if (tlen > len)
2031                         tlen = len;
2032 
2033                 this_cookie = make_cookie(sp->pte_idx,
2034                                           pagesize_code(), off);
2035 
2036                 off = 0;
2037 
2038                 if (this_cookie == sp->prev_cookie) {
2039                         sp->cookies[sp->nc - 1].cookie_size += tlen;
2040                 } else {
2041                         sp->cookies[sp->nc].cookie_addr = this_cookie;
2042                         sp->cookies[sp->nc].cookie_size = tlen;
2043                         sp->nc++;
2044                 }
2045                 sp->prev_cookie = this_cookie + tlen;
2046 
2047                 sp->pte_idx++;
2048 
2049                 len -= tlen;
2050                 pa = new;
2051         } while (len > 0);
2052 }
2053 
2054 static int sg_count_one(struct scatterlist *sg)
2055 {
2056         unsigned long base = page_to_pfn(sg_page(sg)) << PAGE_SHIFT;
2057         long len = sg->length;
2058 
2059         if ((sg->offset | len) & (8UL - 1))
2060                 return -EFAULT;
2061 
2062         return pages_in_region(base + sg->offset, len);
2063 }
2064 
2065 static int sg_count_pages(struct scatterlist *sg, int num_sg)
2066 {
2067         int count;
2068         int i;
2069 
2070         count = 0;
2071         for (i = 0; i < num_sg; i++) {
2072                 int err = sg_count_one(sg + i);
2073                 if (err < 0)
2074                         return err;
2075                 count += err;
2076         }
2077 
2078         return count;
2079 }
2080 
2081 int ldc_map_sg(struct ldc_channel *lp,
2082                struct scatterlist *sg, int num_sg,
2083                struct ldc_trans_cookie *cookies, int ncookies,
2084                unsigned int map_perm)
2085 {
2086         unsigned long i, npages, flags;
2087         struct ldc_mtable_entry *base;
2088         struct cookie_state state;
2089         struct ldc_iommu *iommu;
2090         int err;
2091 
2092         if (map_perm & ~LDC_MAP_ALL)
2093                 return -EINVAL;
2094 
2095         err = sg_count_pages(sg, num_sg);
2096         if (err < 0)
2097                 return err;
2098 
2099         npages = err;
2100         if (err > ncookies)
2101                 return -EMSGSIZE;
2102 
2103         iommu = &lp->iommu;
2104 
2105         spin_lock_irqsave(&iommu->lock, flags);
2106         base = alloc_npages(iommu, npages);
2107         spin_unlock_irqrestore(&iommu->lock, flags);
2108 
2109         if (!base)
2110                 return -ENOMEM;
2111 
2112         state.page_table = iommu->page_table;
2113         state.cookies = cookies;
2114         state.mte_base = perm_to_mte(map_perm);
2115         state.prev_cookie = ~(u64)0;
2116         state.pte_idx = (base - iommu->page_table);
2117         state.nc = 0;
2118 
2119         for (i = 0; i < num_sg; i++)
2120                 fill_cookies(&state, page_to_pfn(sg_page(&sg[i])) << PAGE_SHIFT,
2121                              sg[i].offset, sg[i].length);
2122 
2123         return state.nc;
2124 }
2125 EXPORT_SYMBOL(ldc_map_sg);
2126 
2127 int ldc_map_single(struct ldc_channel *lp,
2128                    void *buf, unsigned int len,
2129                    struct ldc_trans_cookie *cookies, int ncookies,
2130                    unsigned int map_perm)
2131 {
2132         unsigned long npages, pa, flags;
2133         struct ldc_mtable_entry *base;
2134         struct cookie_state state;
2135         struct ldc_iommu *iommu;
2136 
2137         if ((map_perm & ~LDC_MAP_ALL) || (ncookies < 1))
2138                 return -EINVAL;
2139 
2140         pa = __pa(buf);
2141         if ((pa | len) & (8UL - 1))
2142                 return -EFAULT;
2143 
2144         npages = pages_in_region(pa, len);
2145 
2146         iommu = &lp->iommu;
2147 
2148         spin_lock_irqsave(&iommu->lock, flags);
2149         base = alloc_npages(iommu, npages);
2150         spin_unlock_irqrestore(&iommu->lock, flags);
2151 
2152         if (!base)
2153                 return -ENOMEM;
2154 
2155         state.page_table = iommu->page_table;
2156         state.cookies = cookies;
2157         state.mte_base = perm_to_mte(map_perm);
2158         state.prev_cookie = ~(u64)0;
2159         state.pte_idx = (base - iommu->page_table);
2160         state.nc = 0;
2161         fill_cookies(&state, (pa & PAGE_MASK), (pa & ~PAGE_MASK), len);
2162         BUG_ON(state.nc != 1);
2163 
2164         return state.nc;
2165 }
2166 EXPORT_SYMBOL(ldc_map_single);
2167 
2168 static void free_npages(unsigned long id, struct ldc_iommu *iommu,
2169                         u64 cookie, u64 size)
2170 {
2171         struct iommu_arena *arena = &iommu->arena;
2172         unsigned long i, shift, index, npages;
2173         struct ldc_mtable_entry *base;
2174 
2175         npages = PAGE_ALIGN(((cookie & ~PAGE_MASK) + size)) >> PAGE_SHIFT;
2176         index = cookie_to_index(cookie, &shift);
2177         base = iommu->page_table + index;
2178 
2179         BUG_ON(index > arena->limit ||
2180                (index + npages) > arena->limit);
2181 
2182         for (i = 0; i < npages; i++) {
2183                 if (base->cookie)
2184                         sun4v_ldc_revoke(id, cookie + (i << shift),
2185                                          base->cookie);
2186                 base->mte = 0;
2187                 __clear_bit(index + i, arena->map);
2188         }
2189 }
2190 
2191 void ldc_unmap(struct ldc_channel *lp, struct ldc_trans_cookie *cookies,
2192                int ncookies)
2193 {
2194         struct ldc_iommu *iommu = &lp->iommu;
2195         unsigned long flags;
2196         int i;
2197 
2198         spin_lock_irqsave(&iommu->lock, flags);
2199         for (i = 0; i < ncookies; i++) {
2200                 u64 addr = cookies[i].cookie_addr;
2201                 u64 size = cookies[i].cookie_size;
2202 
2203                 free_npages(lp->id, iommu, addr, size);
2204         }
2205         spin_unlock_irqrestore(&iommu->lock, flags);
2206 }
2207 EXPORT_SYMBOL(ldc_unmap);
2208 
2209 int ldc_copy(struct ldc_channel *lp, int copy_dir,
2210              void *buf, unsigned int len, unsigned long offset,
2211              struct ldc_trans_cookie *cookies, int ncookies)
2212 {
2213         unsigned int orig_len;
2214         unsigned long ra;
2215         int i;
2216 
2217         if (copy_dir != LDC_COPY_IN && copy_dir != LDC_COPY_OUT) {
2218                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Bad copy_dir[%d]\n",
2219                        lp->id, copy_dir);
2220                 return -EINVAL;
2221         }
2222 
2223         ra = __pa(buf);
2224         if ((ra | len | offset) & (8UL - 1)) {
2225                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Unaligned buffer "
2226                        "ra[%lx] len[%x] offset[%lx]\n",
2227                        lp->id, ra, len, offset);
2228                 return -EFAULT;
2229         }
2230 
2231         if (lp->hs_state != LDC_HS_COMPLETE ||
2232             (lp->flags & LDC_FLAG_RESET)) {
2233                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] Link down hs_state[%x] "
2234                        "flags[%x]\n", lp->id, lp->hs_state, lp->flags);
2235                 return -ECONNRESET;
2236         }
2237 
2238         orig_len = len;
2239         for (i = 0; i < ncookies; i++) {
2240                 unsigned long cookie_raddr = cookies[i].cookie_addr;
2241                 unsigned long this_len = cookies[i].cookie_size;
2242                 unsigned long actual_len;
2243 
2244                 if (unlikely(offset)) {
2245                         unsigned long this_off = offset;
2246 
2247                         if (this_off > this_len)
2248                                 this_off = this_len;
2249 
2250                         offset -= this_off;
2251                         this_len -= this_off;
2252                         if (!this_len)
2253                                 continue;
2254                         cookie_raddr += this_off;
2255                 }
2256 
2257                 if (this_len > len)
2258                         this_len = len;
2259 
2260                 while (1) {
2261                         unsigned long hv_err;
2262 
2263                         hv_err = sun4v_ldc_copy(lp->id, copy_dir,
2264                                                 cookie_raddr, ra,
2265                                                 this_len, &actual_len);
2266                         if (unlikely(hv_err)) {
2267                                 printk(KERN_ERR PFX "ldc_copy: ID[%lu] "
2268                                        "HV error %lu\n",
2269                                        lp->id, hv_err);
2270                                 if (lp->hs_state != LDC_HS_COMPLETE ||
2271                                     (lp->flags & LDC_FLAG_RESET))
2272                                         return -ECONNRESET;
2273                                 else
2274                                         return -EFAULT;
2275                         }
2276 
2277                         cookie_raddr += actual_len;
2278                         ra += actual_len;
2279                         len -= actual_len;
2280                         if (actual_len == this_len)
2281                                 break;
2282 
2283                         this_len -= actual_len;
2284                 }
2285 
2286                 if (!len)
2287                         break;
2288         }
2289 
2290         /* It is caller policy what to do about short copies.
2291          * For example, a networking driver can declare the
2292          * packet a runt and drop it.
2293          */
2294 
2295         return orig_len - len;
2296 }
2297 EXPORT_SYMBOL(ldc_copy);
2298 
2299 void *ldc_alloc_exp_dring(struct ldc_channel *lp, unsigned int len,
2300                           struct ldc_trans_cookie *cookies, int *ncookies,
2301                           unsigned int map_perm)
2302 {
2303         void *buf;
2304         int err;
2305 
2306         if (len & (8UL - 1))
2307                 return ERR_PTR(-EINVAL);
2308 
2309         buf = kzalloc(len, GFP_KERNEL);
2310         if (!buf)
2311                 return ERR_PTR(-ENOMEM);
2312 
2313         err = ldc_map_single(lp, buf, len, cookies, *ncookies, map_perm);
2314         if (err < 0) {
2315                 kfree(buf);
2316                 return ERR_PTR(err);
2317         }
2318         *ncookies = err;
2319 
2320         return buf;
2321 }
2322 EXPORT_SYMBOL(ldc_alloc_exp_dring);
2323 
2324 void ldc_free_exp_dring(struct ldc_channel *lp, void *buf, unsigned int len,
2325                         struct ldc_trans_cookie *cookies, int ncookies)
2326 {
2327         ldc_unmap(lp, cookies, ncookies);
2328         kfree(buf);
2329 }
2330 EXPORT_SYMBOL(ldc_free_exp_dring);
2331 
2332 static int __init ldc_init(void)
2333 {
2334         unsigned long major, minor;
2335         struct mdesc_handle *hp;
2336         const u64 *v;
2337         int err;
2338         u64 mp;
2339 
2340         hp = mdesc_grab();
2341         if (!hp)
2342                 return -ENODEV;
2343 
2344         mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
2345         err = -ENODEV;
2346         if (mp == MDESC_NODE_NULL)
2347                 goto out;
2348 
2349         v = mdesc_get_property(hp, mp, "domaining-enabled", NULL);
2350         if (!v)
2351                 goto out;
2352 
2353         major = 1;
2354         minor = 0;
2355         if (sun4v_hvapi_register(HV_GRP_LDOM, major, &minor)) {
2356                 printk(KERN_INFO PFX "Could not register LDOM hvapi.\n");
2357                 goto out;
2358         }
2359 
2360         printk(KERN_INFO "%s", version);
2361 
2362         if (!*v) {
2363                 printk(KERN_INFO PFX "Domaining disabled.\n");
2364                 goto out;
2365         }
2366         ldom_domaining_enabled = 1;
2367         err = 0;
2368 
2369 out:
2370         mdesc_release(hp);
2371         return err;
2372 }
2373 
2374 core_initcall(ldc_init);
2375 

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