xref: /linux/drivers/rapidio/rio_cm.c (revision 4f77c3462308c62ffe7129cc18b9ac937f44b5a5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * rio_cm - RapidIO Channelized Messaging Driver
4  *
5  * Copyright 2013-2016 Integrated Device Technology, Inc.
6  * Copyright (c) 2015, Prodrive Technologies
7  * Copyright (c) 2015, RapidIO Trade Association
8  */
9 
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/dma-mapping.h>
13 #include <linux/delay.h>
14 #include <linux/sched.h>
15 #include <linux/rio.h>
16 #include <linux/rio_drv.h>
17 #include <linux/slab.h>
18 #include <linux/idr.h>
19 #include <linux/interrupt.h>
20 #include <linux/cdev.h>
21 #include <linux/fs.h>
22 #include <linux/poll.h>
23 #include <linux/reboot.h>
24 #include <linux/bitops.h>
25 #include <linux/printk.h>
26 #include <linux/rio_cm_cdev.h>
27 
28 #define DRV_NAME        "rio_cm"
29 #define DRV_VERSION     "1.0.0"
30 #define DRV_AUTHOR      "Alexandre Bounine <alexandre.bounine@idt.com>"
31 #define DRV_DESC        "RapidIO Channelized Messaging Driver"
32 #define DEV_NAME	"rio_cm"
33 
34 /* Debug output filtering masks */
35 enum {
36 	DBG_NONE	= 0,
37 	DBG_INIT	= BIT(0), /* driver init */
38 	DBG_EXIT	= BIT(1), /* driver exit */
39 	DBG_MPORT	= BIT(2), /* mport add/remove */
40 	DBG_RDEV	= BIT(3), /* RapidIO device add/remove */
41 	DBG_CHOP	= BIT(4), /* channel operations */
42 	DBG_WAIT	= BIT(5), /* waiting for events */
43 	DBG_TX		= BIT(6), /* message TX */
44 	DBG_TX_EVENT	= BIT(7), /* message TX event */
45 	DBG_RX_DATA	= BIT(8), /* inbound data messages */
46 	DBG_RX_CMD	= BIT(9), /* inbound REQ/ACK/NACK messages */
47 	DBG_ALL		= ~0,
48 };
49 
50 #ifdef DEBUG
51 #define riocm_debug(level, fmt, arg...) \
52 	do { \
53 		if (DBG_##level & dbg_level) \
54 			pr_debug(DRV_NAME ": %s " fmt "\n", \
55 				__func__, ##arg); \
56 	} while (0)
57 #else
58 #define riocm_debug(level, fmt, arg...) \
59 		no_printk(KERN_DEBUG pr_fmt(DRV_NAME fmt "\n"), ##arg)
60 #endif
61 
62 #define riocm_warn(fmt, arg...) \
63 	pr_warn(DRV_NAME ": %s WARNING " fmt "\n", __func__, ##arg)
64 
65 #define riocm_error(fmt, arg...) \
66 	pr_err(DRV_NAME ": %s ERROR " fmt "\n", __func__, ##arg)
67 
68 
69 static int cmbox = 1;
70 module_param(cmbox, int, S_IRUGO);
71 MODULE_PARM_DESC(cmbox, "RapidIO Mailbox number (default 1)");
72 
73 static int chstart = 256;
74 module_param(chstart, int, S_IRUGO);
75 MODULE_PARM_DESC(chstart,
76 		 "Start channel number for dynamic allocation (default 256)");
77 
78 #ifdef DEBUG
79 static u32 dbg_level = DBG_NONE;
80 module_param(dbg_level, uint, S_IWUSR | S_IRUGO);
81 MODULE_PARM_DESC(dbg_level, "Debugging output level (default 0 = none)");
82 #endif
83 
84 MODULE_AUTHOR(DRV_AUTHOR);
85 MODULE_DESCRIPTION(DRV_DESC);
86 MODULE_LICENSE("GPL");
87 MODULE_VERSION(DRV_VERSION);
88 
89 #define RIOCM_TX_RING_SIZE	128
90 #define RIOCM_RX_RING_SIZE	128
91 #define RIOCM_CONNECT_TO	3 /* connect response TO (in sec) */
92 
93 #define RIOCM_MAX_CHNUM		0xffff /* Use full range of u16 field */
94 #define RIOCM_CHNUM_AUTO	0
95 #define RIOCM_MAX_EP_COUNT	0x10000 /* Max number of endpoints */
96 
97 enum rio_cm_state {
98 	RIO_CM_IDLE,
99 	RIO_CM_CONNECT,
100 	RIO_CM_CONNECTED,
101 	RIO_CM_DISCONNECT,
102 	RIO_CM_CHAN_BOUND,
103 	RIO_CM_LISTEN,
104 	RIO_CM_DESTROYING,
105 };
106 
107 enum rio_cm_pkt_type {
108 	RIO_CM_SYS	= 0xaa,
109 	RIO_CM_CHAN	= 0x55,
110 };
111 
112 enum rio_cm_chop {
113 	CM_CONN_REQ,
114 	CM_CONN_ACK,
115 	CM_CONN_CLOSE,
116 	CM_DATA_MSG,
117 };
118 
119 struct rio_ch_base_bhdr {
120 	u32 src_id;
121 	u32 dst_id;
122 #define RIO_HDR_LETTER_MASK 0xffff0000
123 #define RIO_HDR_MBOX_MASK   0x0000ffff
124 	u8  src_mbox;
125 	u8  dst_mbox;
126 	u8  type;
127 } __attribute__((__packed__));
128 
129 struct rio_ch_chan_hdr {
130 	struct rio_ch_base_bhdr bhdr;
131 	u8 ch_op;
132 	u16 dst_ch;
133 	u16 src_ch;
134 	u16 msg_len;
135 	u16 rsrvd;
136 } __attribute__((__packed__));
137 
138 struct tx_req {
139 	struct list_head node;
140 	struct rio_dev   *rdev;
141 	void		 *buffer;
142 	size_t		 len;
143 };
144 
145 struct cm_dev {
146 	struct list_head	list;
147 	struct rio_mport	*mport;
148 	void			*rx_buf[RIOCM_RX_RING_SIZE];
149 	int			rx_slots;
150 	struct mutex		rx_lock;
151 
152 	void			*tx_buf[RIOCM_TX_RING_SIZE];
153 	int			tx_slot;
154 	int			tx_cnt;
155 	int			tx_ack_slot;
156 	struct list_head	tx_reqs;
157 	spinlock_t		tx_lock;
158 
159 	struct list_head	peers;
160 	u32			npeers;
161 	struct workqueue_struct *rx_wq;
162 	struct work_struct	rx_work;
163 };
164 
165 struct chan_rx_ring {
166 	void	*buf[RIOCM_RX_RING_SIZE];
167 	int	head;
168 	int	tail;
169 	int	count;
170 
171 	/* Tracking RX buffers reported to upper level */
172 	void	*inuse[RIOCM_RX_RING_SIZE];
173 	int	inuse_cnt;
174 };
175 
176 struct rio_channel {
177 	u16			id;	/* local channel ID */
178 	struct kref		ref;	/* channel refcount */
179 	struct file		*filp;
180 	struct cm_dev		*cmdev;	/* associated CM device object */
181 	struct rio_dev		*rdev;	/* remote RapidIO device */
182 	enum rio_cm_state	state;
183 	int			error;
184 	spinlock_t		lock;
185 	void			*context;
186 	u32			loc_destid;	/* local destID */
187 	u32			rem_destid;	/* remote destID */
188 	u16			rem_channel;	/* remote channel ID */
189 	struct list_head	accept_queue;
190 	struct list_head	ch_node;
191 	struct completion	comp;
192 	struct completion	comp_close;
193 	struct chan_rx_ring	rx_ring;
194 };
195 
196 struct cm_peer {
197 	struct list_head node;
198 	struct rio_dev *rdev;
199 };
200 
201 struct rio_cm_work {
202 	struct work_struct work;
203 	struct cm_dev *cm;
204 	void *data;
205 };
206 
207 struct conn_req {
208 	struct list_head node;
209 	u32 destid;	/* requester destID */
210 	u16 chan;	/* requester channel ID */
211 	struct cm_dev *cmdev;
212 };
213 
214 /*
215  * A channel_dev structure represents a CM_CDEV
216  * @cdev	Character device
217  * @dev		Associated device object
218  */
219 struct channel_dev {
220 	struct cdev	cdev;
221 	struct device	*dev;
222 };
223 
224 static struct rio_channel *riocm_ch_alloc(u16 ch_num);
225 static void riocm_ch_free(struct kref *ref);
226 static int riocm_post_send(struct cm_dev *cm, struct rio_dev *rdev,
227 			   void *buffer, size_t len);
228 static int riocm_ch_close(struct rio_channel *ch);
229 
230 static DEFINE_SPINLOCK(idr_lock);
231 static DEFINE_IDR(ch_idr);
232 
233 static LIST_HEAD(cm_dev_list);
234 static DECLARE_RWSEM(rdev_sem);
235 
236 static const struct class dev_class = {
237 	.name = DRV_NAME,
238 };
239 static unsigned int dev_major;
240 static unsigned int dev_minor_base;
241 static dev_t dev_number;
242 static struct channel_dev riocm_cdev;
243 
244 #define is_msg_capable(src_ops, dst_ops)			\
245 			((src_ops & RIO_SRC_OPS_DATA_MSG) &&	\
246 			 (dst_ops & RIO_DST_OPS_DATA_MSG))
247 #define dev_cm_capable(dev) \
248 	is_msg_capable(dev->src_ops, dev->dst_ops)
249 
250 static int riocm_cmp(struct rio_channel *ch, enum rio_cm_state cmp)
251 {
252 	int ret;
253 
254 	spin_lock_bh(&ch->lock);
255 	ret = (ch->state == cmp);
256 	spin_unlock_bh(&ch->lock);
257 	return ret;
258 }
259 
260 static int riocm_cmp_exch(struct rio_channel *ch,
261 			   enum rio_cm_state cmp, enum rio_cm_state exch)
262 {
263 	int ret;
264 
265 	spin_lock_bh(&ch->lock);
266 	ret = (ch->state == cmp);
267 	if (ret)
268 		ch->state = exch;
269 	spin_unlock_bh(&ch->lock);
270 	return ret;
271 }
272 
273 static enum rio_cm_state riocm_exch(struct rio_channel *ch,
274 				    enum rio_cm_state exch)
275 {
276 	enum rio_cm_state old;
277 
278 	spin_lock_bh(&ch->lock);
279 	old = ch->state;
280 	ch->state = exch;
281 	spin_unlock_bh(&ch->lock);
282 	return old;
283 }
284 
285 static struct rio_channel *riocm_get_channel(u16 nr)
286 {
287 	struct rio_channel *ch;
288 
289 	spin_lock_bh(&idr_lock);
290 	ch = idr_find(&ch_idr, nr);
291 	if (ch)
292 		kref_get(&ch->ref);
293 	spin_unlock_bh(&idr_lock);
294 	return ch;
295 }
296 
297 static void riocm_put_channel(struct rio_channel *ch)
298 {
299 	kref_put(&ch->ref, riocm_ch_free);
300 }
301 
302 static void *riocm_rx_get_msg(struct cm_dev *cm)
303 {
304 	void *msg;
305 	int i;
306 
307 	msg = rio_get_inb_message(cm->mport, cmbox);
308 	if (msg) {
309 		for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
310 			if (cm->rx_buf[i] == msg) {
311 				cm->rx_buf[i] = NULL;
312 				cm->rx_slots++;
313 				break;
314 			}
315 		}
316 
317 		if (i == RIOCM_RX_RING_SIZE)
318 			riocm_warn("no record for buffer 0x%p", msg);
319 	}
320 
321 	return msg;
322 }
323 
324 /*
325  * riocm_rx_fill - fills a ring of receive buffers for given cm device
326  * @cm: cm_dev object
327  * @nent: max number of entries to fill
328  *
329  * Returns: none
330  */
331 static void riocm_rx_fill(struct cm_dev *cm, int nent)
332 {
333 	int i;
334 
335 	if (cm->rx_slots == 0)
336 		return;
337 
338 	for (i = 0; i < RIOCM_RX_RING_SIZE && cm->rx_slots && nent; i++) {
339 		if (cm->rx_buf[i] == NULL) {
340 			cm->rx_buf[i] = kmalloc(RIO_MAX_MSG_SIZE, GFP_KERNEL);
341 			if (cm->rx_buf[i] == NULL)
342 				break;
343 			rio_add_inb_buffer(cm->mport, cmbox, cm->rx_buf[i]);
344 			cm->rx_slots--;
345 			nent--;
346 		}
347 	}
348 }
349 
350 /*
351  * riocm_rx_free - frees all receive buffers associated with given cm device
352  * @cm: cm_dev object
353  *
354  * Returns: none
355  */
356 static void riocm_rx_free(struct cm_dev *cm)
357 {
358 	int i;
359 
360 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
361 		if (cm->rx_buf[i] != NULL) {
362 			kfree(cm->rx_buf[i]);
363 			cm->rx_buf[i] = NULL;
364 		}
365 	}
366 }
367 
368 /*
369  * riocm_req_handler - connection request handler
370  * @cm: cm_dev object
371  * @req_data: pointer to the request packet
372  *
373  * Returns: 0 if success, or
374  *          -EINVAL if channel is not in correct state,
375  *          -ENODEV if cannot find a channel with specified ID,
376  *          -ENOMEM if unable to allocate memory to store the request
377  */
378 static int riocm_req_handler(struct cm_dev *cm, void *req_data)
379 {
380 	struct rio_channel *ch;
381 	struct conn_req *req;
382 	struct rio_ch_chan_hdr *hh = req_data;
383 	u16 chnum;
384 
385 	chnum = ntohs(hh->dst_ch);
386 
387 	ch = riocm_get_channel(chnum);
388 
389 	if (!ch)
390 		return -ENODEV;
391 
392 	if (ch->state != RIO_CM_LISTEN) {
393 		riocm_debug(RX_CMD, "channel %d is not in listen state", chnum);
394 		riocm_put_channel(ch);
395 		return -EINVAL;
396 	}
397 
398 	req = kzalloc(sizeof(*req), GFP_KERNEL);
399 	if (!req) {
400 		riocm_put_channel(ch);
401 		return -ENOMEM;
402 	}
403 
404 	req->destid = ntohl(hh->bhdr.src_id);
405 	req->chan = ntohs(hh->src_ch);
406 	req->cmdev = cm;
407 
408 	spin_lock_bh(&ch->lock);
409 	list_add_tail(&req->node, &ch->accept_queue);
410 	spin_unlock_bh(&ch->lock);
411 	complete(&ch->comp);
412 	riocm_put_channel(ch);
413 
414 	return 0;
415 }
416 
417 /*
418  * riocm_resp_handler - response to connection request handler
419  * @resp_data: pointer to the response packet
420  *
421  * Returns: 0 if success, or
422  *          -EINVAL if channel is not in correct state,
423  *          -ENODEV if cannot find a channel with specified ID,
424  */
425 static int riocm_resp_handler(void *resp_data)
426 {
427 	struct rio_channel *ch;
428 	struct rio_ch_chan_hdr *hh = resp_data;
429 	u16 chnum;
430 
431 	chnum = ntohs(hh->dst_ch);
432 	ch = riocm_get_channel(chnum);
433 	if (!ch)
434 		return -ENODEV;
435 
436 	if (ch->state != RIO_CM_CONNECT) {
437 		riocm_put_channel(ch);
438 		return -EINVAL;
439 	}
440 
441 	riocm_exch(ch, RIO_CM_CONNECTED);
442 	ch->rem_channel = ntohs(hh->src_ch);
443 	complete(&ch->comp);
444 	riocm_put_channel(ch);
445 
446 	return 0;
447 }
448 
449 /*
450  * riocm_close_handler - channel close request handler
451  * @req_data: pointer to the request packet
452  *
453  * Returns: 0 if success, or
454  *          -ENODEV if cannot find a channel with specified ID,
455  *            + error codes returned by riocm_ch_close.
456  */
457 static int riocm_close_handler(void *data)
458 {
459 	struct rio_channel *ch;
460 	struct rio_ch_chan_hdr *hh = data;
461 	int ret;
462 
463 	riocm_debug(RX_CMD, "for ch=%d", ntohs(hh->dst_ch));
464 
465 	spin_lock_bh(&idr_lock);
466 	ch = idr_find(&ch_idr, ntohs(hh->dst_ch));
467 	if (!ch) {
468 		spin_unlock_bh(&idr_lock);
469 		return -ENODEV;
470 	}
471 	idr_remove(&ch_idr, ch->id);
472 	spin_unlock_bh(&idr_lock);
473 
474 	riocm_exch(ch, RIO_CM_DISCONNECT);
475 
476 	ret = riocm_ch_close(ch);
477 	if (ret)
478 		riocm_debug(RX_CMD, "riocm_ch_close() returned %d", ret);
479 
480 	return 0;
481 }
482 
483 /*
484  * rio_cm_handler - function that services request (non-data) packets
485  * @cm: cm_dev object
486  * @data: pointer to the packet
487  */
488 static void rio_cm_handler(struct cm_dev *cm, void *data)
489 {
490 	struct rio_ch_chan_hdr *hdr;
491 
492 	if (!rio_mport_is_running(cm->mport))
493 		goto out;
494 
495 	hdr = data;
496 
497 	riocm_debug(RX_CMD, "OP=%x for ch=%d from %d",
498 		    hdr->ch_op, ntohs(hdr->dst_ch), ntohs(hdr->src_ch));
499 
500 	switch (hdr->ch_op) {
501 	case CM_CONN_REQ:
502 		riocm_req_handler(cm, data);
503 		break;
504 	case CM_CONN_ACK:
505 		riocm_resp_handler(data);
506 		break;
507 	case CM_CONN_CLOSE:
508 		riocm_close_handler(data);
509 		break;
510 	default:
511 		riocm_error("Invalid packet header");
512 		break;
513 	}
514 out:
515 	kfree(data);
516 }
517 
518 /*
519  * rio_rx_data_handler - received data packet handler
520  * @cm: cm_dev object
521  * @buf: data packet
522  *
523  * Returns: 0 if success, or
524  *          -ENODEV if cannot find a channel with specified ID,
525  *          -EIO if channel is not in CONNECTED state,
526  *          -ENOMEM if channel RX queue is full (packet discarded)
527  */
528 static int rio_rx_data_handler(struct cm_dev *cm, void *buf)
529 {
530 	struct rio_ch_chan_hdr *hdr;
531 	struct rio_channel *ch;
532 
533 	hdr = buf;
534 
535 	riocm_debug(RX_DATA, "for ch=%d", ntohs(hdr->dst_ch));
536 
537 	ch = riocm_get_channel(ntohs(hdr->dst_ch));
538 	if (!ch) {
539 		/* Discard data message for non-existing channel */
540 		kfree(buf);
541 		return -ENODEV;
542 	}
543 
544 	/* Place pointer to the buffer into channel's RX queue */
545 	spin_lock(&ch->lock);
546 
547 	if (ch->state != RIO_CM_CONNECTED) {
548 		/* Channel is not ready to receive data, discard a packet */
549 		riocm_debug(RX_DATA, "ch=%d is in wrong state=%d",
550 			    ch->id, ch->state);
551 		spin_unlock(&ch->lock);
552 		kfree(buf);
553 		riocm_put_channel(ch);
554 		return -EIO;
555 	}
556 
557 	if (ch->rx_ring.count == RIOCM_RX_RING_SIZE) {
558 		/* If RX ring is full, discard a packet */
559 		riocm_debug(RX_DATA, "ch=%d is full", ch->id);
560 		spin_unlock(&ch->lock);
561 		kfree(buf);
562 		riocm_put_channel(ch);
563 		return -ENOMEM;
564 	}
565 
566 	ch->rx_ring.buf[ch->rx_ring.head] = buf;
567 	ch->rx_ring.head++;
568 	ch->rx_ring.count++;
569 	ch->rx_ring.head %= RIOCM_RX_RING_SIZE;
570 
571 	complete(&ch->comp);
572 
573 	spin_unlock(&ch->lock);
574 	riocm_put_channel(ch);
575 
576 	return 0;
577 }
578 
579 /*
580  * rio_ibmsg_handler - inbound message packet handler
581  */
582 static void rio_ibmsg_handler(struct work_struct *work)
583 {
584 	struct cm_dev *cm = container_of(work, struct cm_dev, rx_work);
585 	void *data;
586 	struct rio_ch_chan_hdr *hdr;
587 
588 	if (!rio_mport_is_running(cm->mport))
589 		return;
590 
591 	while (1) {
592 		mutex_lock(&cm->rx_lock);
593 		data = riocm_rx_get_msg(cm);
594 		if (data)
595 			riocm_rx_fill(cm, 1);
596 		mutex_unlock(&cm->rx_lock);
597 
598 		if (data == NULL)
599 			break;
600 
601 		hdr = data;
602 
603 		if (hdr->bhdr.type != RIO_CM_CHAN) {
604 			/* For now simply discard packets other than channel */
605 			riocm_error("Unsupported TYPE code (0x%x). Msg dropped",
606 				    hdr->bhdr.type);
607 			kfree(data);
608 			continue;
609 		}
610 
611 		/* Process a channel message */
612 		if (hdr->ch_op == CM_DATA_MSG)
613 			rio_rx_data_handler(cm, data);
614 		else
615 			rio_cm_handler(cm, data);
616 	}
617 }
618 
619 static void riocm_inb_msg_event(struct rio_mport *mport, void *dev_id,
620 				int mbox, int slot)
621 {
622 	struct cm_dev *cm = dev_id;
623 
624 	if (rio_mport_is_running(cm->mport) && !work_pending(&cm->rx_work))
625 		queue_work(cm->rx_wq, &cm->rx_work);
626 }
627 
628 /*
629  * rio_txcq_handler - TX completion handler
630  * @cm: cm_dev object
631  * @slot: TX queue slot
632  *
633  * TX completion handler also ensures that pending request packets are placed
634  * into transmit queue as soon as a free slot becomes available. This is done
635  * to give higher priority to request packets during high intensity data flow.
636  */
637 static void rio_txcq_handler(struct cm_dev *cm, int slot)
638 {
639 	int ack_slot;
640 
641 	/* ATTN: Add TX completion notification if/when direct buffer
642 	 * transfer is implemented. At this moment only correct tracking
643 	 * of tx_count is important.
644 	 */
645 	riocm_debug(TX_EVENT, "for mport_%d slot %d tx_cnt %d",
646 		    cm->mport->id, slot, cm->tx_cnt);
647 
648 	spin_lock(&cm->tx_lock);
649 	ack_slot = cm->tx_ack_slot;
650 
651 	if (ack_slot == slot)
652 		riocm_debug(TX_EVENT, "slot == ack_slot");
653 
654 	while (cm->tx_cnt && ((ack_slot != slot) ||
655 	       (cm->tx_cnt == RIOCM_TX_RING_SIZE))) {
656 
657 		cm->tx_buf[ack_slot] = NULL;
658 		++ack_slot;
659 		ack_slot &= (RIOCM_TX_RING_SIZE - 1);
660 		cm->tx_cnt--;
661 	}
662 
663 	if (cm->tx_cnt < 0 || cm->tx_cnt > RIOCM_TX_RING_SIZE)
664 		riocm_error("tx_cnt %d out of sync", cm->tx_cnt);
665 
666 	WARN_ON((cm->tx_cnt < 0) || (cm->tx_cnt > RIOCM_TX_RING_SIZE));
667 
668 	cm->tx_ack_slot = ack_slot;
669 
670 	/*
671 	 * If there are pending requests, insert them into transmit queue
672 	 */
673 	if (!list_empty(&cm->tx_reqs) && (cm->tx_cnt < RIOCM_TX_RING_SIZE)) {
674 		struct tx_req *req, *_req;
675 		int rc;
676 
677 		list_for_each_entry_safe(req, _req, &cm->tx_reqs, node) {
678 			list_del(&req->node);
679 			cm->tx_buf[cm->tx_slot] = req->buffer;
680 			rc = rio_add_outb_message(cm->mport, req->rdev, cmbox,
681 						  req->buffer, req->len);
682 			kfree(req->buffer);
683 			kfree(req);
684 
685 			++cm->tx_cnt;
686 			++cm->tx_slot;
687 			cm->tx_slot &= (RIOCM_TX_RING_SIZE - 1);
688 			if (cm->tx_cnt == RIOCM_TX_RING_SIZE)
689 				break;
690 		}
691 	}
692 
693 	spin_unlock(&cm->tx_lock);
694 }
695 
696 static void riocm_outb_msg_event(struct rio_mport *mport, void *dev_id,
697 				 int mbox, int slot)
698 {
699 	struct cm_dev *cm = dev_id;
700 
701 	if (cm && rio_mport_is_running(cm->mport))
702 		rio_txcq_handler(cm, slot);
703 }
704 
705 static int riocm_queue_req(struct cm_dev *cm, struct rio_dev *rdev,
706 			   void *buffer, size_t len)
707 {
708 	unsigned long flags;
709 	struct tx_req *treq;
710 
711 	treq = kzalloc(sizeof(*treq), GFP_KERNEL);
712 	if (treq == NULL)
713 		return -ENOMEM;
714 
715 	treq->rdev = rdev;
716 	treq->buffer = buffer;
717 	treq->len = len;
718 
719 	spin_lock_irqsave(&cm->tx_lock, flags);
720 	list_add_tail(&treq->node, &cm->tx_reqs);
721 	spin_unlock_irqrestore(&cm->tx_lock, flags);
722 	return 0;
723 }
724 
725 /*
726  * riocm_post_send - helper function that places packet into msg TX queue
727  * @cm: cm_dev object
728  * @rdev: target RapidIO device object (required by outbound msg interface)
729  * @buffer: pointer to a packet buffer to send
730  * @len: length of data to transfer
731  * @req: request priority flag
732  *
733  * Returns: 0 if success, or error code otherwise.
734  */
735 static int riocm_post_send(struct cm_dev *cm, struct rio_dev *rdev,
736 			   void *buffer, size_t len)
737 {
738 	int rc;
739 	unsigned long flags;
740 
741 	spin_lock_irqsave(&cm->tx_lock, flags);
742 
743 	if (cm->mport == NULL) {
744 		rc = -ENODEV;
745 		goto err_out;
746 	}
747 
748 	if (cm->tx_cnt == RIOCM_TX_RING_SIZE) {
749 		riocm_debug(TX, "Tx Queue is full");
750 		rc = -EBUSY;
751 		goto err_out;
752 	}
753 
754 	cm->tx_buf[cm->tx_slot] = buffer;
755 	rc = rio_add_outb_message(cm->mport, rdev, cmbox, buffer, len);
756 
757 	riocm_debug(TX, "Add buf@%p destid=%x tx_slot=%d tx_cnt=%d",
758 		 buffer, rdev->destid, cm->tx_slot, cm->tx_cnt);
759 
760 	++cm->tx_cnt;
761 	++cm->tx_slot;
762 	cm->tx_slot &= (RIOCM_TX_RING_SIZE - 1);
763 
764 err_out:
765 	spin_unlock_irqrestore(&cm->tx_lock, flags);
766 	return rc;
767 }
768 
769 /*
770  * riocm_ch_send - sends a data packet to a remote device
771  * @ch_id: local channel ID
772  * @buf: pointer to a data buffer to send (including CM header)
773  * @len: length of data to transfer (including CM header)
774  *
775  * ATTN: ASSUMES THAT THE HEADER SPACE IS RESERVED PART OF THE DATA PACKET
776  *
777  * Returns: 0 if success, or
778  *          -EINVAL if one or more input parameters is/are not valid,
779  *          -ENODEV if cannot find a channel with specified ID,
780  *          -EAGAIN if a channel is not in CONNECTED state,
781  *	    + error codes returned by HW send routine.
782  */
783 static int riocm_ch_send(u16 ch_id, void *buf, int len)
784 {
785 	struct rio_channel *ch;
786 	struct rio_ch_chan_hdr *hdr;
787 	int ret;
788 
789 	if (buf == NULL || ch_id == 0 || len == 0 || len > RIO_MAX_MSG_SIZE)
790 		return -EINVAL;
791 
792 	ch = riocm_get_channel(ch_id);
793 	if (!ch) {
794 		riocm_error("%s(%d) ch_%d not found", current->comm,
795 			    task_pid_nr(current), ch_id);
796 		return -ENODEV;
797 	}
798 
799 	if (!riocm_cmp(ch, RIO_CM_CONNECTED)) {
800 		ret = -EAGAIN;
801 		goto err_out;
802 	}
803 
804 	/*
805 	 * Fill buffer header section with corresponding channel data
806 	 */
807 	hdr = buf;
808 
809 	hdr->bhdr.src_id = htonl(ch->loc_destid);
810 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
811 	hdr->bhdr.src_mbox = cmbox;
812 	hdr->bhdr.dst_mbox = cmbox;
813 	hdr->bhdr.type = RIO_CM_CHAN;
814 	hdr->ch_op = CM_DATA_MSG;
815 	hdr->dst_ch = htons(ch->rem_channel);
816 	hdr->src_ch = htons(ch->id);
817 	hdr->msg_len = htons((u16)len);
818 
819 	/* ATTN: the function call below relies on the fact that underlying
820 	 * HW-specific add_outb_message() routine copies TX data into its own
821 	 * internal transfer buffer (true for all RIONET compatible mport
822 	 * drivers). Must be reviewed if mport driver uses the buffer directly.
823 	 */
824 
825 	ret = riocm_post_send(ch->cmdev, ch->rdev, buf, len);
826 	if (ret)
827 		riocm_debug(TX, "ch %d send_err=%d", ch->id, ret);
828 err_out:
829 	riocm_put_channel(ch);
830 	return ret;
831 }
832 
833 static int riocm_ch_free_rxbuf(struct rio_channel *ch, void *buf)
834 {
835 	int i, ret = -EINVAL;
836 
837 	spin_lock_bh(&ch->lock);
838 
839 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
840 		if (ch->rx_ring.inuse[i] == buf) {
841 			ch->rx_ring.inuse[i] = NULL;
842 			ch->rx_ring.inuse_cnt--;
843 			ret = 0;
844 			break;
845 		}
846 	}
847 
848 	spin_unlock_bh(&ch->lock);
849 
850 	if (!ret)
851 		kfree(buf);
852 
853 	return ret;
854 }
855 
856 /*
857  * riocm_ch_receive - fetch a data packet received for the specified channel
858  * @ch: local channel ID
859  * @buf: pointer to a packet buffer
860  * @timeout: timeout to wait for incoming packet (in jiffies)
861  *
862  * Returns: 0 and valid buffer pointer if success, or NULL pointer and one of:
863  *          -EAGAIN if a channel is not in CONNECTED state,
864  *          -ENOMEM if in-use tracking queue is full,
865  *          -ETIME if wait timeout expired,
866  *	    -EINTR if wait was interrupted.
867  */
868 static int riocm_ch_receive(struct rio_channel *ch, void **buf, long timeout)
869 {
870 	void *rxmsg = NULL;
871 	int i, ret = 0;
872 	long wret;
873 
874 	if (!riocm_cmp(ch, RIO_CM_CONNECTED)) {
875 		ret = -EAGAIN;
876 		goto out;
877 	}
878 
879 	if (ch->rx_ring.inuse_cnt == RIOCM_RX_RING_SIZE) {
880 		/* If we do not have entries to track buffers given to upper
881 		 * layer, reject request.
882 		 */
883 		ret = -ENOMEM;
884 		goto out;
885 	}
886 
887 	wret = wait_for_completion_interruptible_timeout(&ch->comp, timeout);
888 
889 	riocm_debug(WAIT, "wait on %d returned %ld", ch->id, wret);
890 
891 	if (!wret)
892 		ret = -ETIME;
893 	else if (wret == -ERESTARTSYS)
894 		ret = -EINTR;
895 	else
896 		ret = riocm_cmp(ch, RIO_CM_CONNECTED) ? 0 : -ECONNRESET;
897 
898 	if (ret)
899 		goto out;
900 
901 	spin_lock_bh(&ch->lock);
902 
903 	rxmsg = ch->rx_ring.buf[ch->rx_ring.tail];
904 	ch->rx_ring.buf[ch->rx_ring.tail] = NULL;
905 	ch->rx_ring.count--;
906 	ch->rx_ring.tail++;
907 	ch->rx_ring.tail %= RIOCM_RX_RING_SIZE;
908 	ret = -ENOMEM;
909 
910 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
911 		if (ch->rx_ring.inuse[i] == NULL) {
912 			ch->rx_ring.inuse[i] = rxmsg;
913 			ch->rx_ring.inuse_cnt++;
914 			ret = 0;
915 			break;
916 		}
917 	}
918 
919 	if (ret) {
920 		/* We have no entry to store pending message: drop it */
921 		kfree(rxmsg);
922 		rxmsg = NULL;
923 	}
924 
925 	spin_unlock_bh(&ch->lock);
926 out:
927 	*buf = rxmsg;
928 	return ret;
929 }
930 
931 /*
932  * riocm_ch_connect - sends a connect request to a remote device
933  * @loc_ch: local channel ID
934  * @cm: CM device to send connect request
935  * @peer: target RapidIO device
936  * @rem_ch: remote channel ID
937  *
938  * Returns: 0 if success, or
939  *          -EINVAL if the channel is not in IDLE state,
940  *          -EAGAIN if no connection request available immediately,
941  *          -ETIME if ACK response timeout expired,
942  *          -EINTR if wait for response was interrupted.
943  */
944 static int riocm_ch_connect(u16 loc_ch, struct cm_dev *cm,
945 			    struct cm_peer *peer, u16 rem_ch)
946 {
947 	struct rio_channel *ch = NULL;
948 	struct rio_ch_chan_hdr *hdr;
949 	int ret;
950 	long wret;
951 
952 	ch = riocm_get_channel(loc_ch);
953 	if (!ch)
954 		return -ENODEV;
955 
956 	if (!riocm_cmp_exch(ch, RIO_CM_IDLE, RIO_CM_CONNECT)) {
957 		ret = -EINVAL;
958 		goto conn_done;
959 	}
960 
961 	ch->cmdev = cm;
962 	ch->rdev = peer->rdev;
963 	ch->context = NULL;
964 	ch->loc_destid = cm->mport->host_deviceid;
965 	ch->rem_channel = rem_ch;
966 
967 	/*
968 	 * Send connect request to the remote RapidIO device
969 	 */
970 
971 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
972 	if (hdr == NULL) {
973 		ret = -ENOMEM;
974 		goto conn_done;
975 	}
976 
977 	hdr->bhdr.src_id = htonl(ch->loc_destid);
978 	hdr->bhdr.dst_id = htonl(peer->rdev->destid);
979 	hdr->bhdr.src_mbox = cmbox;
980 	hdr->bhdr.dst_mbox = cmbox;
981 	hdr->bhdr.type = RIO_CM_CHAN;
982 	hdr->ch_op = CM_CONN_REQ;
983 	hdr->dst_ch = htons(rem_ch);
984 	hdr->src_ch = htons(loc_ch);
985 
986 	/* ATTN: the function call below relies on the fact that underlying
987 	 * HW-specific add_outb_message() routine copies TX data into its
988 	 * internal transfer buffer. Must be reviewed if mport driver uses
989 	 * this buffer directly.
990 	 */
991 	ret = riocm_post_send(cm, peer->rdev, hdr, sizeof(*hdr));
992 
993 	if (ret != -EBUSY) {
994 		kfree(hdr);
995 	} else {
996 		ret = riocm_queue_req(cm, peer->rdev, hdr, sizeof(*hdr));
997 		if (ret)
998 			kfree(hdr);
999 	}
1000 
1001 	if (ret) {
1002 		riocm_cmp_exch(ch, RIO_CM_CONNECT, RIO_CM_IDLE);
1003 		goto conn_done;
1004 	}
1005 
1006 	/* Wait for connect response from the remote device */
1007 	wret = wait_for_completion_interruptible_timeout(&ch->comp,
1008 							 RIOCM_CONNECT_TO * HZ);
1009 	riocm_debug(WAIT, "wait on %d returns %ld", ch->id, wret);
1010 
1011 	if (!wret)
1012 		ret = -ETIME;
1013 	else if (wret == -ERESTARTSYS)
1014 		ret = -EINTR;
1015 	else
1016 		ret = riocm_cmp(ch, RIO_CM_CONNECTED) ? 0 : -1;
1017 
1018 conn_done:
1019 	riocm_put_channel(ch);
1020 	return ret;
1021 }
1022 
1023 static int riocm_send_ack(struct rio_channel *ch)
1024 {
1025 	struct rio_ch_chan_hdr *hdr;
1026 	int ret;
1027 
1028 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
1029 	if (hdr == NULL)
1030 		return -ENOMEM;
1031 
1032 	hdr->bhdr.src_id = htonl(ch->loc_destid);
1033 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
1034 	hdr->dst_ch = htons(ch->rem_channel);
1035 	hdr->src_ch = htons(ch->id);
1036 	hdr->bhdr.src_mbox = cmbox;
1037 	hdr->bhdr.dst_mbox = cmbox;
1038 	hdr->bhdr.type = RIO_CM_CHAN;
1039 	hdr->ch_op = CM_CONN_ACK;
1040 
1041 	/* ATTN: the function call below relies on the fact that underlying
1042 	 * add_outb_message() routine copies TX data into its internal transfer
1043 	 * buffer. Review if switching to direct buffer version.
1044 	 */
1045 	ret = riocm_post_send(ch->cmdev, ch->rdev, hdr, sizeof(*hdr));
1046 
1047 	if (ret == -EBUSY && !riocm_queue_req(ch->cmdev,
1048 					      ch->rdev, hdr, sizeof(*hdr)))
1049 		return 0;
1050 	kfree(hdr);
1051 
1052 	if (ret)
1053 		riocm_error("send ACK to ch_%d on %s failed (ret=%d)",
1054 			    ch->id, rio_name(ch->rdev), ret);
1055 	return ret;
1056 }
1057 
1058 /*
1059  * riocm_ch_accept - accept incoming connection request
1060  * @ch_id: channel ID
1061  * @new_ch_id: local mport device
1062  * @timeout: wait timeout (if 0 non-blocking call, do not wait if connection
1063  *           request is not available).
1064  *
1065  * Returns: pointer to new channel struct if success, or error-valued pointer:
1066  *          -ENODEV - cannot find specified channel or mport,
1067  *          -EINVAL - the channel is not in IDLE state,
1068  *          -EAGAIN - no connection request available immediately (timeout=0),
1069  *          -ENOMEM - unable to allocate new channel,
1070  *          -ETIME - wait timeout expired,
1071  *          -EINTR - wait was interrupted.
1072  */
1073 static struct rio_channel *riocm_ch_accept(u16 ch_id, u16 *new_ch_id,
1074 					   long timeout)
1075 {
1076 	struct rio_channel *ch;
1077 	struct rio_channel *new_ch;
1078 	struct conn_req *req;
1079 	struct cm_peer *peer;
1080 	int found = 0;
1081 	int err = 0;
1082 	long wret;
1083 
1084 	ch = riocm_get_channel(ch_id);
1085 	if (!ch)
1086 		return ERR_PTR(-EINVAL);
1087 
1088 	if (!riocm_cmp(ch, RIO_CM_LISTEN)) {
1089 		err = -EINVAL;
1090 		goto err_put;
1091 	}
1092 
1093 	/* Don't sleep if this is a non blocking call */
1094 	if (!timeout) {
1095 		if (!try_wait_for_completion(&ch->comp)) {
1096 			err = -EAGAIN;
1097 			goto err_put;
1098 		}
1099 	} else {
1100 		riocm_debug(WAIT, "on %d", ch->id);
1101 
1102 		wret = wait_for_completion_interruptible_timeout(&ch->comp,
1103 								 timeout);
1104 		if (!wret) {
1105 			err = -ETIME;
1106 			goto err_put;
1107 		} else if (wret == -ERESTARTSYS) {
1108 			err = -EINTR;
1109 			goto err_put;
1110 		}
1111 	}
1112 
1113 	spin_lock_bh(&ch->lock);
1114 
1115 	if (ch->state != RIO_CM_LISTEN) {
1116 		err = -ECANCELED;
1117 	} else if (list_empty(&ch->accept_queue)) {
1118 		riocm_debug(WAIT, "on %d accept_queue is empty on completion",
1119 			    ch->id);
1120 		err = -EIO;
1121 	}
1122 
1123 	spin_unlock_bh(&ch->lock);
1124 
1125 	if (err) {
1126 		riocm_debug(WAIT, "on %d returns %d", ch->id, err);
1127 		goto err_put;
1128 	}
1129 
1130 	/* Create new channel for this connection */
1131 	new_ch = riocm_ch_alloc(RIOCM_CHNUM_AUTO);
1132 
1133 	if (IS_ERR(new_ch)) {
1134 		riocm_error("failed to get channel for new req (%ld)",
1135 			PTR_ERR(new_ch));
1136 		err = -ENOMEM;
1137 		goto err_put;
1138 	}
1139 
1140 	spin_lock_bh(&ch->lock);
1141 
1142 	req = list_first_entry(&ch->accept_queue, struct conn_req, node);
1143 	list_del(&req->node);
1144 	new_ch->cmdev = ch->cmdev;
1145 	new_ch->loc_destid = ch->loc_destid;
1146 	new_ch->rem_destid = req->destid;
1147 	new_ch->rem_channel = req->chan;
1148 
1149 	spin_unlock_bh(&ch->lock);
1150 	riocm_put_channel(ch);
1151 	ch = NULL;
1152 	kfree(req);
1153 
1154 	down_read(&rdev_sem);
1155 	/* Find requester's device object */
1156 	list_for_each_entry(peer, &new_ch->cmdev->peers, node) {
1157 		if (peer->rdev->destid == new_ch->rem_destid) {
1158 			riocm_debug(RX_CMD, "found matching device(%s)",
1159 				    rio_name(peer->rdev));
1160 			found = 1;
1161 			break;
1162 		}
1163 	}
1164 	up_read(&rdev_sem);
1165 
1166 	if (!found) {
1167 		/* If peer device object not found, simply ignore the request */
1168 		err = -ENODEV;
1169 		goto err_put_new_ch;
1170 	}
1171 
1172 	new_ch->rdev = peer->rdev;
1173 	new_ch->state = RIO_CM_CONNECTED;
1174 	spin_lock_init(&new_ch->lock);
1175 
1176 	/* Acknowledge the connection request. */
1177 	riocm_send_ack(new_ch);
1178 
1179 	*new_ch_id = new_ch->id;
1180 	return new_ch;
1181 
1182 err_put_new_ch:
1183 	spin_lock_bh(&idr_lock);
1184 	idr_remove(&ch_idr, new_ch->id);
1185 	spin_unlock_bh(&idr_lock);
1186 	riocm_put_channel(new_ch);
1187 
1188 err_put:
1189 	if (ch)
1190 		riocm_put_channel(ch);
1191 	*new_ch_id = 0;
1192 	return ERR_PTR(err);
1193 }
1194 
1195 /*
1196  * riocm_ch_listen - puts a channel into LISTEN state
1197  * @ch_id: channel ID
1198  *
1199  * Returns: 0 if success, or
1200  *          -EINVAL if the specified channel does not exists or
1201  *                  is not in CHAN_BOUND state.
1202  */
1203 static int riocm_ch_listen(u16 ch_id)
1204 {
1205 	struct rio_channel *ch = NULL;
1206 	int ret = 0;
1207 
1208 	riocm_debug(CHOP, "(ch_%d)", ch_id);
1209 
1210 	ch = riocm_get_channel(ch_id);
1211 	if (!ch)
1212 		return -EINVAL;
1213 	if (!riocm_cmp_exch(ch, RIO_CM_CHAN_BOUND, RIO_CM_LISTEN))
1214 		ret = -EINVAL;
1215 	riocm_put_channel(ch);
1216 	return ret;
1217 }
1218 
1219 /*
1220  * riocm_ch_bind - associate a channel object and an mport device
1221  * @ch_id: channel ID
1222  * @mport_id: local mport device ID
1223  * @context: pointer to the additional caller's context
1224  *
1225  * Returns: 0 if success, or
1226  *          -ENODEV if cannot find specified mport,
1227  *          -EINVAL if the specified channel does not exist or
1228  *                  is not in IDLE state.
1229  */
1230 static int riocm_ch_bind(u16 ch_id, u8 mport_id, void *context)
1231 {
1232 	struct rio_channel *ch = NULL;
1233 	struct cm_dev *cm;
1234 	int rc = -ENODEV;
1235 
1236 	riocm_debug(CHOP, "ch_%d to mport_%d", ch_id, mport_id);
1237 
1238 	/* Find matching cm_dev object */
1239 	down_read(&rdev_sem);
1240 	list_for_each_entry(cm, &cm_dev_list, list) {
1241 		if ((cm->mport->id == mport_id) &&
1242 		     rio_mport_is_running(cm->mport)) {
1243 			rc = 0;
1244 			break;
1245 		}
1246 	}
1247 
1248 	if (rc)
1249 		goto exit;
1250 
1251 	ch = riocm_get_channel(ch_id);
1252 	if (!ch) {
1253 		rc = -EINVAL;
1254 		goto exit;
1255 	}
1256 
1257 	spin_lock_bh(&ch->lock);
1258 	if (ch->state != RIO_CM_IDLE) {
1259 		spin_unlock_bh(&ch->lock);
1260 		rc = -EINVAL;
1261 		goto err_put;
1262 	}
1263 
1264 	ch->cmdev = cm;
1265 	ch->loc_destid = cm->mport->host_deviceid;
1266 	ch->context = context;
1267 	ch->state = RIO_CM_CHAN_BOUND;
1268 	spin_unlock_bh(&ch->lock);
1269 err_put:
1270 	riocm_put_channel(ch);
1271 exit:
1272 	up_read(&rdev_sem);
1273 	return rc;
1274 }
1275 
1276 /*
1277  * riocm_ch_alloc - channel object allocation helper routine
1278  * @ch_num: channel ID (1 ... RIOCM_MAX_CHNUM, 0 = automatic)
1279  *
1280  * Return value: pointer to newly created channel object,
1281  *               or error-valued pointer
1282  */
1283 static struct rio_channel *riocm_ch_alloc(u16 ch_num)
1284 {
1285 	int id;
1286 	int start, end;
1287 	struct rio_channel *ch;
1288 
1289 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
1290 	if (!ch)
1291 		return ERR_PTR(-ENOMEM);
1292 
1293 	if (ch_num) {
1294 		/* If requested, try to obtain the specified channel ID */
1295 		start = ch_num;
1296 		end = ch_num + 1;
1297 	} else {
1298 		/* Obtain channel ID from the dynamic allocation range */
1299 		start = chstart;
1300 		end = RIOCM_MAX_CHNUM + 1;
1301 	}
1302 
1303 	idr_preload(GFP_KERNEL);
1304 	spin_lock_bh(&idr_lock);
1305 	id = idr_alloc_cyclic(&ch_idr, ch, start, end, GFP_NOWAIT);
1306 	spin_unlock_bh(&idr_lock);
1307 	idr_preload_end();
1308 
1309 	if (id < 0) {
1310 		kfree(ch);
1311 		return ERR_PTR(id == -ENOSPC ? -EBUSY : id);
1312 	}
1313 
1314 	ch->id = (u16)id;
1315 	ch->state = RIO_CM_IDLE;
1316 	spin_lock_init(&ch->lock);
1317 	INIT_LIST_HEAD(&ch->accept_queue);
1318 	INIT_LIST_HEAD(&ch->ch_node);
1319 	init_completion(&ch->comp);
1320 	init_completion(&ch->comp_close);
1321 	kref_init(&ch->ref);
1322 	ch->rx_ring.head = 0;
1323 	ch->rx_ring.tail = 0;
1324 	ch->rx_ring.count = 0;
1325 	ch->rx_ring.inuse_cnt = 0;
1326 
1327 	return ch;
1328 }
1329 
1330 /*
1331  * riocm_ch_create - creates a new channel object and allocates ID for it
1332  * @ch_num: channel ID (1 ... RIOCM_MAX_CHNUM, 0 = automatic)
1333  *
1334  * Allocates and initializes a new channel object. If the parameter ch_num > 0
1335  * and is within the valid range, riocm_ch_create tries to allocate the
1336  * specified ID for the new channel. If ch_num = 0, channel ID will be assigned
1337  * automatically from the range (chstart ... RIOCM_MAX_CHNUM).
1338  * Module parameter 'chstart' defines start of an ID range available for dynamic
1339  * allocation. Range below 'chstart' is reserved for pre-defined ID numbers.
1340  * Available channel numbers are limited by 16-bit size of channel numbers used
1341  * in the packet header.
1342  *
1343  * Return value: PTR to rio_channel structure if successful (with channel number
1344  *               updated via pointer) or error-valued pointer if error.
1345  */
1346 static struct rio_channel *riocm_ch_create(u16 *ch_num)
1347 {
1348 	struct rio_channel *ch = NULL;
1349 
1350 	ch = riocm_ch_alloc(*ch_num);
1351 
1352 	if (IS_ERR(ch))
1353 		riocm_debug(CHOP, "Failed to allocate channel %d (err=%ld)",
1354 			    *ch_num, PTR_ERR(ch));
1355 	else
1356 		*ch_num = ch->id;
1357 
1358 	return ch;
1359 }
1360 
1361 /*
1362  * riocm_ch_free - channel object release routine
1363  * @ref: pointer to a channel's kref structure
1364  */
1365 static void riocm_ch_free(struct kref *ref)
1366 {
1367 	struct rio_channel *ch = container_of(ref, struct rio_channel, ref);
1368 	int i;
1369 
1370 	riocm_debug(CHOP, "(ch_%d)", ch->id);
1371 
1372 	if (ch->rx_ring.inuse_cnt) {
1373 		for (i = 0;
1374 		     i < RIOCM_RX_RING_SIZE && ch->rx_ring.inuse_cnt; i++) {
1375 			if (ch->rx_ring.inuse[i] != NULL) {
1376 				kfree(ch->rx_ring.inuse[i]);
1377 				ch->rx_ring.inuse_cnt--;
1378 			}
1379 		}
1380 	}
1381 
1382 	if (ch->rx_ring.count)
1383 		for (i = 0; i < RIOCM_RX_RING_SIZE && ch->rx_ring.count; i++) {
1384 			if (ch->rx_ring.buf[i] != NULL) {
1385 				kfree(ch->rx_ring.buf[i]);
1386 				ch->rx_ring.count--;
1387 			}
1388 		}
1389 
1390 	complete(&ch->comp_close);
1391 }
1392 
1393 static int riocm_send_close(struct rio_channel *ch)
1394 {
1395 	struct rio_ch_chan_hdr *hdr;
1396 	int ret;
1397 
1398 	/*
1399 	 * Send CH_CLOSE notification to the remote RapidIO device
1400 	 */
1401 
1402 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
1403 	if (hdr == NULL)
1404 		return -ENOMEM;
1405 
1406 	hdr->bhdr.src_id = htonl(ch->loc_destid);
1407 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
1408 	hdr->bhdr.src_mbox = cmbox;
1409 	hdr->bhdr.dst_mbox = cmbox;
1410 	hdr->bhdr.type = RIO_CM_CHAN;
1411 	hdr->ch_op = CM_CONN_CLOSE;
1412 	hdr->dst_ch = htons(ch->rem_channel);
1413 	hdr->src_ch = htons(ch->id);
1414 
1415 	/* ATTN: the function call below relies on the fact that underlying
1416 	 * add_outb_message() routine copies TX data into its internal transfer
1417 	 * buffer. Needs to be reviewed if switched to direct buffer mode.
1418 	 */
1419 	ret = riocm_post_send(ch->cmdev, ch->rdev, hdr, sizeof(*hdr));
1420 
1421 	if (ret == -EBUSY && !riocm_queue_req(ch->cmdev, ch->rdev,
1422 					      hdr, sizeof(*hdr)))
1423 		return 0;
1424 	kfree(hdr);
1425 
1426 	if (ret)
1427 		riocm_error("ch(%d) send CLOSE failed (ret=%d)", ch->id, ret);
1428 
1429 	return ret;
1430 }
1431 
1432 /*
1433  * riocm_ch_close - closes a channel object with specified ID (by local request)
1434  * @ch: channel to be closed
1435  */
1436 static int riocm_ch_close(struct rio_channel *ch)
1437 {
1438 	unsigned long tmo = msecs_to_jiffies(3000);
1439 	enum rio_cm_state state;
1440 	long wret;
1441 	int ret = 0;
1442 
1443 	riocm_debug(CHOP, "ch_%d by %s(%d)",
1444 		    ch->id, current->comm, task_pid_nr(current));
1445 
1446 	state = riocm_exch(ch, RIO_CM_DESTROYING);
1447 	if (state == RIO_CM_CONNECTED)
1448 		riocm_send_close(ch);
1449 
1450 	complete_all(&ch->comp);
1451 
1452 	riocm_put_channel(ch);
1453 	wret = wait_for_completion_interruptible_timeout(&ch->comp_close, tmo);
1454 
1455 	riocm_debug(WAIT, "wait on %d returns %ld", ch->id, wret);
1456 
1457 	if (wret == 0) {
1458 		/* Timeout on wait occurred */
1459 		riocm_debug(CHOP, "%s(%d) timed out waiting for ch %d",
1460 		       current->comm, task_pid_nr(current), ch->id);
1461 		ret = -ETIMEDOUT;
1462 	} else if (wret == -ERESTARTSYS) {
1463 		/* Wait_for_completion was interrupted by a signal */
1464 		riocm_debug(CHOP, "%s(%d) wait for ch %d was interrupted",
1465 			current->comm, task_pid_nr(current), ch->id);
1466 		ret = -EINTR;
1467 	}
1468 
1469 	if (!ret) {
1470 		riocm_debug(CHOP, "ch_%d resources released", ch->id);
1471 		kfree(ch);
1472 	} else {
1473 		riocm_debug(CHOP, "failed to release ch_%d resources", ch->id);
1474 	}
1475 
1476 	return ret;
1477 }
1478 
1479 /*
1480  * riocm_cdev_open() - Open character device
1481  */
1482 static int riocm_cdev_open(struct inode *inode, struct file *filp)
1483 {
1484 	riocm_debug(INIT, "by %s(%d) filp=%p ",
1485 		    current->comm, task_pid_nr(current), filp);
1486 
1487 	if (list_empty(&cm_dev_list))
1488 		return -ENODEV;
1489 
1490 	return 0;
1491 }
1492 
1493 /*
1494  * riocm_cdev_release() - Release character device
1495  */
1496 static int riocm_cdev_release(struct inode *inode, struct file *filp)
1497 {
1498 	struct rio_channel *ch, *_c;
1499 	unsigned int i;
1500 	LIST_HEAD(list);
1501 
1502 	riocm_debug(EXIT, "by %s(%d) filp=%p",
1503 		    current->comm, task_pid_nr(current), filp);
1504 
1505 	/* Check if there are channels associated with this file descriptor */
1506 	spin_lock_bh(&idr_lock);
1507 	idr_for_each_entry(&ch_idr, ch, i) {
1508 		if (ch && ch->filp == filp) {
1509 			riocm_debug(EXIT, "ch_%d not released by %s(%d)",
1510 				    ch->id, current->comm,
1511 				    task_pid_nr(current));
1512 			idr_remove(&ch_idr, ch->id);
1513 			list_add(&ch->ch_node, &list);
1514 		}
1515 	}
1516 	spin_unlock_bh(&idr_lock);
1517 
1518 	if (!list_empty(&list)) {
1519 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
1520 			list_del(&ch->ch_node);
1521 			riocm_ch_close(ch);
1522 		}
1523 	}
1524 
1525 	return 0;
1526 }
1527 
1528 /*
1529  * cm_ep_get_list_size() - Reports number of endpoints in the network
1530  */
1531 static int cm_ep_get_list_size(void __user *arg)
1532 {
1533 	u32 __user *p = arg;
1534 	u32 mport_id;
1535 	u32 count = 0;
1536 	struct cm_dev *cm;
1537 
1538 	if (get_user(mport_id, p))
1539 		return -EFAULT;
1540 	if (mport_id >= RIO_MAX_MPORTS)
1541 		return -EINVAL;
1542 
1543 	/* Find a matching cm_dev object */
1544 	down_read(&rdev_sem);
1545 	list_for_each_entry(cm, &cm_dev_list, list) {
1546 		if (cm->mport->id == mport_id) {
1547 			count = cm->npeers;
1548 			up_read(&rdev_sem);
1549 			if (copy_to_user(arg, &count, sizeof(u32)))
1550 				return -EFAULT;
1551 			return 0;
1552 		}
1553 	}
1554 	up_read(&rdev_sem);
1555 
1556 	return -ENODEV;
1557 }
1558 
1559 /*
1560  * cm_ep_get_list() - Returns list of attached endpoints
1561  */
1562 static int cm_ep_get_list(void __user *arg)
1563 {
1564 	struct cm_dev *cm;
1565 	struct cm_peer *peer;
1566 	u32 info[2];
1567 	void *buf;
1568 	u32 nent;
1569 	u32 *entry_ptr;
1570 	u32 i = 0;
1571 	int ret = 0;
1572 
1573 	if (copy_from_user(&info, arg, sizeof(info)))
1574 		return -EFAULT;
1575 
1576 	if (info[1] >= RIO_MAX_MPORTS || info[0] > RIOCM_MAX_EP_COUNT)
1577 		return -EINVAL;
1578 
1579 	/* Find a matching cm_dev object */
1580 	down_read(&rdev_sem);
1581 	list_for_each_entry(cm, &cm_dev_list, list)
1582 		if (cm->mport->id == (u8)info[1])
1583 			goto found;
1584 
1585 	up_read(&rdev_sem);
1586 	return -ENODEV;
1587 
1588 found:
1589 	nent = min(info[0], cm->npeers);
1590 	buf = kcalloc(nent + 2, sizeof(u32), GFP_KERNEL);
1591 	if (!buf) {
1592 		up_read(&rdev_sem);
1593 		return -ENOMEM;
1594 	}
1595 
1596 	entry_ptr = (u32 *)((uintptr_t)buf + 2*sizeof(u32));
1597 
1598 	list_for_each_entry(peer, &cm->peers, node) {
1599 		*entry_ptr = (u32)peer->rdev->destid;
1600 		entry_ptr++;
1601 		if (++i == nent)
1602 			break;
1603 	}
1604 	up_read(&rdev_sem);
1605 
1606 	((u32 *)buf)[0] = i; /* report an updated number of entries */
1607 	((u32 *)buf)[1] = info[1]; /* put back an mport ID */
1608 	if (copy_to_user(arg, buf, sizeof(u32) * (info[0] + 2)))
1609 		ret = -EFAULT;
1610 
1611 	kfree(buf);
1612 	return ret;
1613 }
1614 
1615 /*
1616  * cm_mport_get_list() - Returns list of available local mport devices
1617  */
1618 static int cm_mport_get_list(void __user *arg)
1619 {
1620 	int ret = 0;
1621 	u32 entries;
1622 	void *buf;
1623 	struct cm_dev *cm;
1624 	u32 *entry_ptr;
1625 	int count = 0;
1626 
1627 	if (copy_from_user(&entries, arg, sizeof(entries)))
1628 		return -EFAULT;
1629 	if (entries == 0 || entries > RIO_MAX_MPORTS)
1630 		return -EINVAL;
1631 	buf = kcalloc(entries + 1, sizeof(u32), GFP_KERNEL);
1632 	if (!buf)
1633 		return -ENOMEM;
1634 
1635 	/* Scan all registered cm_dev objects */
1636 	entry_ptr = (u32 *)((uintptr_t)buf + sizeof(u32));
1637 	down_read(&rdev_sem);
1638 	list_for_each_entry(cm, &cm_dev_list, list) {
1639 		if (count++ < entries) {
1640 			*entry_ptr = (cm->mport->id << 16) |
1641 				      cm->mport->host_deviceid;
1642 			entry_ptr++;
1643 		}
1644 	}
1645 	up_read(&rdev_sem);
1646 
1647 	*((u32 *)buf) = count; /* report a real number of entries */
1648 	if (copy_to_user(arg, buf, sizeof(u32) * (count + 1)))
1649 		ret = -EFAULT;
1650 
1651 	kfree(buf);
1652 	return ret;
1653 }
1654 
1655 /*
1656  * cm_chan_create() - Create a message exchange channel
1657  */
1658 static int cm_chan_create(struct file *filp, void __user *arg)
1659 {
1660 	u16 __user *p = arg;
1661 	u16 ch_num;
1662 	struct rio_channel *ch;
1663 
1664 	if (get_user(ch_num, p))
1665 		return -EFAULT;
1666 
1667 	riocm_debug(CHOP, "ch_%d requested by %s(%d)",
1668 		    ch_num, current->comm, task_pid_nr(current));
1669 	ch = riocm_ch_create(&ch_num);
1670 	if (IS_ERR(ch))
1671 		return PTR_ERR(ch);
1672 
1673 	ch->filp = filp;
1674 	riocm_debug(CHOP, "ch_%d created by %s(%d)",
1675 		    ch_num, current->comm, task_pid_nr(current));
1676 	return put_user(ch_num, p);
1677 }
1678 
1679 /*
1680  * cm_chan_close() - Close channel
1681  * @filp:	Pointer to file object
1682  * @arg:	Channel to close
1683  */
1684 static int cm_chan_close(struct file *filp, void __user *arg)
1685 {
1686 	u16 __user *p = arg;
1687 	u16 ch_num;
1688 	struct rio_channel *ch;
1689 
1690 	if (get_user(ch_num, p))
1691 		return -EFAULT;
1692 
1693 	riocm_debug(CHOP, "ch_%d by %s(%d)",
1694 		    ch_num, current->comm, task_pid_nr(current));
1695 
1696 	spin_lock_bh(&idr_lock);
1697 	ch = idr_find(&ch_idr, ch_num);
1698 	if (!ch) {
1699 		spin_unlock_bh(&idr_lock);
1700 		return 0;
1701 	}
1702 	if (ch->filp != filp) {
1703 		spin_unlock_bh(&idr_lock);
1704 		return -EINVAL;
1705 	}
1706 	idr_remove(&ch_idr, ch->id);
1707 	spin_unlock_bh(&idr_lock);
1708 
1709 	return riocm_ch_close(ch);
1710 }
1711 
1712 /*
1713  * cm_chan_bind() - Bind channel
1714  * @arg:	Channel number
1715  */
1716 static int cm_chan_bind(void __user *arg)
1717 {
1718 	struct rio_cm_channel chan;
1719 
1720 	if (copy_from_user(&chan, arg, sizeof(chan)))
1721 		return -EFAULT;
1722 	if (chan.mport_id >= RIO_MAX_MPORTS)
1723 		return -EINVAL;
1724 
1725 	return riocm_ch_bind(chan.id, chan.mport_id, NULL);
1726 }
1727 
1728 /*
1729  * cm_chan_listen() - Listen on channel
1730  * @arg:	Channel number
1731  */
1732 static int cm_chan_listen(void __user *arg)
1733 {
1734 	u16 __user *p = arg;
1735 	u16 ch_num;
1736 
1737 	if (get_user(ch_num, p))
1738 		return -EFAULT;
1739 
1740 	return riocm_ch_listen(ch_num);
1741 }
1742 
1743 /*
1744  * cm_chan_accept() - Accept incoming connection
1745  * @filp:	Pointer to file object
1746  * @arg:	Channel number
1747  */
1748 static int cm_chan_accept(struct file *filp, void __user *arg)
1749 {
1750 	struct rio_cm_accept param;
1751 	long accept_to;
1752 	struct rio_channel *ch;
1753 
1754 	if (copy_from_user(&param, arg, sizeof(param)))
1755 		return -EFAULT;
1756 
1757 	riocm_debug(CHOP, "on ch_%d by %s(%d)",
1758 		    param.ch_num, current->comm, task_pid_nr(current));
1759 
1760 	accept_to = param.wait_to ?
1761 			msecs_to_jiffies(param.wait_to) : 0;
1762 
1763 	ch = riocm_ch_accept(param.ch_num, &param.ch_num, accept_to);
1764 	if (IS_ERR(ch))
1765 		return PTR_ERR(ch);
1766 	ch->filp = filp;
1767 
1768 	riocm_debug(CHOP, "new ch_%d for %s(%d)",
1769 		    ch->id, current->comm, task_pid_nr(current));
1770 
1771 	if (copy_to_user(arg, &param, sizeof(param)))
1772 		return -EFAULT;
1773 	return 0;
1774 }
1775 
1776 /*
1777  * cm_chan_connect() - Connect on channel
1778  * @arg:	Channel information
1779  */
1780 static int cm_chan_connect(void __user *arg)
1781 {
1782 	struct rio_cm_channel chan;
1783 	struct cm_dev *cm;
1784 	struct cm_peer *peer;
1785 	int ret = -ENODEV;
1786 
1787 	if (copy_from_user(&chan, arg, sizeof(chan)))
1788 		return -EFAULT;
1789 	if (chan.mport_id >= RIO_MAX_MPORTS)
1790 		return -EINVAL;
1791 
1792 	down_read(&rdev_sem);
1793 
1794 	/* Find matching cm_dev object */
1795 	list_for_each_entry(cm, &cm_dev_list, list) {
1796 		if (cm->mport->id == chan.mport_id) {
1797 			ret = 0;
1798 			break;
1799 		}
1800 	}
1801 
1802 	if (ret)
1803 		goto err_out;
1804 
1805 	if (chan.remote_destid >= RIO_ANY_DESTID(cm->mport->sys_size)) {
1806 		ret = -EINVAL;
1807 		goto err_out;
1808 	}
1809 
1810 	/* Find corresponding RapidIO endpoint device object */
1811 	ret = -ENODEV;
1812 
1813 	list_for_each_entry(peer, &cm->peers, node) {
1814 		if (peer->rdev->destid == chan.remote_destid) {
1815 			ret = 0;
1816 			break;
1817 		}
1818 	}
1819 
1820 	if (ret)
1821 		goto err_out;
1822 
1823 	up_read(&rdev_sem);
1824 
1825 	return riocm_ch_connect(chan.id, cm, peer, chan.remote_channel);
1826 err_out:
1827 	up_read(&rdev_sem);
1828 	return ret;
1829 }
1830 
1831 /*
1832  * cm_chan_msg_send() - Send a message through channel
1833  * @arg:	Outbound message information
1834  */
1835 static int cm_chan_msg_send(void __user *arg)
1836 {
1837 	struct rio_cm_msg msg;
1838 	void *buf;
1839 	int ret;
1840 
1841 	if (copy_from_user(&msg, arg, sizeof(msg)))
1842 		return -EFAULT;
1843 	if (msg.size > RIO_MAX_MSG_SIZE)
1844 		return -EINVAL;
1845 
1846 	buf = memdup_user((void __user *)(uintptr_t)msg.msg, msg.size);
1847 	if (IS_ERR(buf))
1848 		return PTR_ERR(buf);
1849 
1850 	ret = riocm_ch_send(msg.ch_num, buf, msg.size);
1851 
1852 	kfree(buf);
1853 	return ret;
1854 }
1855 
1856 /*
1857  * cm_chan_msg_rcv() - Receive a message through channel
1858  * @arg:	Inbound message information
1859  */
1860 static int cm_chan_msg_rcv(void __user *arg)
1861 {
1862 	struct rio_cm_msg msg;
1863 	struct rio_channel *ch;
1864 	void *buf;
1865 	long rxto;
1866 	int ret = 0, msg_size;
1867 
1868 	if (copy_from_user(&msg, arg, sizeof(msg)))
1869 		return -EFAULT;
1870 
1871 	if (msg.ch_num == 0 || msg.size == 0)
1872 		return -EINVAL;
1873 
1874 	ch = riocm_get_channel(msg.ch_num);
1875 	if (!ch)
1876 		return -ENODEV;
1877 
1878 	rxto = msg.rxto ? msecs_to_jiffies(msg.rxto) : MAX_SCHEDULE_TIMEOUT;
1879 
1880 	ret = riocm_ch_receive(ch, &buf, rxto);
1881 	if (ret)
1882 		goto out;
1883 
1884 	msg_size = min(msg.size, (u16)(RIO_MAX_MSG_SIZE));
1885 
1886 	if (copy_to_user((void __user *)(uintptr_t)msg.msg, buf, msg_size))
1887 		ret = -EFAULT;
1888 
1889 	riocm_ch_free_rxbuf(ch, buf);
1890 out:
1891 	riocm_put_channel(ch);
1892 	return ret;
1893 }
1894 
1895 /*
1896  * riocm_cdev_ioctl() - IOCTL requests handler
1897  */
1898 static long
1899 riocm_cdev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1900 {
1901 	switch (cmd) {
1902 	case RIO_CM_EP_GET_LIST_SIZE:
1903 		return cm_ep_get_list_size((void __user *)arg);
1904 	case RIO_CM_EP_GET_LIST:
1905 		return cm_ep_get_list((void __user *)arg);
1906 	case RIO_CM_CHAN_CREATE:
1907 		return cm_chan_create(filp, (void __user *)arg);
1908 	case RIO_CM_CHAN_CLOSE:
1909 		return cm_chan_close(filp, (void __user *)arg);
1910 	case RIO_CM_CHAN_BIND:
1911 		return cm_chan_bind((void __user *)arg);
1912 	case RIO_CM_CHAN_LISTEN:
1913 		return cm_chan_listen((void __user *)arg);
1914 	case RIO_CM_CHAN_ACCEPT:
1915 		return cm_chan_accept(filp, (void __user *)arg);
1916 	case RIO_CM_CHAN_CONNECT:
1917 		return cm_chan_connect((void __user *)arg);
1918 	case RIO_CM_CHAN_SEND:
1919 		return cm_chan_msg_send((void __user *)arg);
1920 	case RIO_CM_CHAN_RECEIVE:
1921 		return cm_chan_msg_rcv((void __user *)arg);
1922 	case RIO_CM_MPORT_GET_LIST:
1923 		return cm_mport_get_list((void __user *)arg);
1924 	default:
1925 		break;
1926 	}
1927 
1928 	return -EINVAL;
1929 }
1930 
1931 static const struct file_operations riocm_cdev_fops = {
1932 	.owner		= THIS_MODULE,
1933 	.open		= riocm_cdev_open,
1934 	.release	= riocm_cdev_release,
1935 	.unlocked_ioctl = riocm_cdev_ioctl,
1936 };
1937 
1938 /*
1939  * riocm_add_dev - add new remote RapidIO device into channel management core
1940  * @dev: device object associated with RapidIO device
1941  * @sif: subsystem interface
1942  *
1943  * Adds the specified RapidIO device (if applicable) into peers list of
1944  * the corresponding channel management device (cm_dev).
1945  */
1946 static int riocm_add_dev(struct device *dev, struct subsys_interface *sif)
1947 {
1948 	struct cm_peer *peer;
1949 	struct rio_dev *rdev = to_rio_dev(dev);
1950 	struct cm_dev *cm;
1951 
1952 	/* Check if the remote device has capabilities required to support CM */
1953 	if (!dev_cm_capable(rdev))
1954 		return 0;
1955 
1956 	riocm_debug(RDEV, "(%s)", rio_name(rdev));
1957 
1958 	peer = kmalloc(sizeof(*peer), GFP_KERNEL);
1959 	if (!peer)
1960 		return -ENOMEM;
1961 
1962 	/* Find a corresponding cm_dev object */
1963 	down_write(&rdev_sem);
1964 	list_for_each_entry(cm, &cm_dev_list, list) {
1965 		if (cm->mport == rdev->net->hport)
1966 			goto found;
1967 	}
1968 
1969 	up_write(&rdev_sem);
1970 	kfree(peer);
1971 	return -ENODEV;
1972 
1973 found:
1974 	peer->rdev = rdev;
1975 	list_add_tail(&peer->node, &cm->peers);
1976 	cm->npeers++;
1977 
1978 	up_write(&rdev_sem);
1979 	return 0;
1980 }
1981 
1982 /*
1983  * riocm_remove_dev - remove remote RapidIO device from channel management core
1984  * @dev: device object associated with RapidIO device
1985  * @sif: subsystem interface
1986  *
1987  * Removes the specified RapidIO device (if applicable) from peers list of
1988  * the corresponding channel management device (cm_dev).
1989  */
1990 static void riocm_remove_dev(struct device *dev, struct subsys_interface *sif)
1991 {
1992 	struct rio_dev *rdev = to_rio_dev(dev);
1993 	struct cm_dev *cm;
1994 	struct cm_peer *peer;
1995 	struct rio_channel *ch, *_c;
1996 	unsigned int i;
1997 	bool found = false;
1998 	LIST_HEAD(list);
1999 
2000 	/* Check if the remote device has capabilities required to support CM */
2001 	if (!dev_cm_capable(rdev))
2002 		return;
2003 
2004 	riocm_debug(RDEV, "(%s)", rio_name(rdev));
2005 
2006 	/* Find matching cm_dev object */
2007 	down_write(&rdev_sem);
2008 	list_for_each_entry(cm, &cm_dev_list, list) {
2009 		if (cm->mport == rdev->net->hport) {
2010 			found = true;
2011 			break;
2012 		}
2013 	}
2014 
2015 	if (!found) {
2016 		up_write(&rdev_sem);
2017 		return;
2018 	}
2019 
2020 	/* Remove remote device from the list of peers */
2021 	found = false;
2022 	list_for_each_entry(peer, &cm->peers, node) {
2023 		if (peer->rdev == rdev) {
2024 			riocm_debug(RDEV, "removing peer %s", rio_name(rdev));
2025 			found = true;
2026 			list_del(&peer->node);
2027 			cm->npeers--;
2028 			kfree(peer);
2029 			break;
2030 		}
2031 	}
2032 
2033 	up_write(&rdev_sem);
2034 
2035 	if (!found)
2036 		return;
2037 
2038 	/*
2039 	 * Release channels associated with this peer
2040 	 */
2041 
2042 	spin_lock_bh(&idr_lock);
2043 	idr_for_each_entry(&ch_idr, ch, i) {
2044 		if (ch && ch->rdev == rdev) {
2045 			if (atomic_read(&rdev->state) != RIO_DEVICE_SHUTDOWN)
2046 				riocm_exch(ch, RIO_CM_DISCONNECT);
2047 			idr_remove(&ch_idr, ch->id);
2048 			list_add(&ch->ch_node, &list);
2049 		}
2050 	}
2051 	spin_unlock_bh(&idr_lock);
2052 
2053 	if (!list_empty(&list)) {
2054 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
2055 			list_del(&ch->ch_node);
2056 			riocm_ch_close(ch);
2057 		}
2058 	}
2059 }
2060 
2061 /*
2062  * riocm_cdev_add() - Create rio_cm char device
2063  * @devno: device number assigned to device (MAJ + MIN)
2064  */
2065 static int riocm_cdev_add(dev_t devno)
2066 {
2067 	int ret;
2068 
2069 	cdev_init(&riocm_cdev.cdev, &riocm_cdev_fops);
2070 	riocm_cdev.cdev.owner = THIS_MODULE;
2071 	ret = cdev_add(&riocm_cdev.cdev, devno, 1);
2072 	if (ret < 0) {
2073 		riocm_error("Cannot register a device with error %d", ret);
2074 		return ret;
2075 	}
2076 
2077 	riocm_cdev.dev = device_create(&dev_class, NULL, devno, NULL, DEV_NAME);
2078 	if (IS_ERR(riocm_cdev.dev)) {
2079 		cdev_del(&riocm_cdev.cdev);
2080 		return PTR_ERR(riocm_cdev.dev);
2081 	}
2082 
2083 	riocm_debug(MPORT, "Added %s cdev(%d:%d)",
2084 		    DEV_NAME, MAJOR(devno), MINOR(devno));
2085 
2086 	return 0;
2087 }
2088 
2089 /*
2090  * riocm_add_mport - add new local mport device into channel management core
2091  * @dev: device object associated with mport
2092  *
2093  * When a new mport device is added, CM immediately reserves inbound and
2094  * outbound RapidIO mailboxes that will be used.
2095  */
2096 static int riocm_add_mport(struct device *dev)
2097 {
2098 	int rc;
2099 	int i;
2100 	struct cm_dev *cm;
2101 	struct rio_mport *mport = to_rio_mport(dev);
2102 
2103 	riocm_debug(MPORT, "add mport %s", mport->name);
2104 
2105 	cm = kzalloc(sizeof(*cm), GFP_KERNEL);
2106 	if (!cm)
2107 		return -ENOMEM;
2108 
2109 	cm->mport = mport;
2110 
2111 	rc = rio_request_outb_mbox(mport, cm, cmbox,
2112 				   RIOCM_TX_RING_SIZE, riocm_outb_msg_event);
2113 	if (rc) {
2114 		riocm_error("failed to allocate OBMBOX_%d on %s",
2115 			    cmbox, mport->name);
2116 		kfree(cm);
2117 		return -ENODEV;
2118 	}
2119 
2120 	rc = rio_request_inb_mbox(mport, cm, cmbox,
2121 				  RIOCM_RX_RING_SIZE, riocm_inb_msg_event);
2122 	if (rc) {
2123 		riocm_error("failed to allocate IBMBOX_%d on %s",
2124 			    cmbox, mport->name);
2125 		rio_release_outb_mbox(mport, cmbox);
2126 		kfree(cm);
2127 		return -ENODEV;
2128 	}
2129 
2130 	cm->rx_wq = create_workqueue(DRV_NAME "/rxq");
2131 	if (!cm->rx_wq) {
2132 		rio_release_inb_mbox(mport, cmbox);
2133 		rio_release_outb_mbox(mport, cmbox);
2134 		kfree(cm);
2135 		return -ENOMEM;
2136 	}
2137 
2138 	/*
2139 	 * Allocate and register inbound messaging buffers to be ready
2140 	 * to receive channel and system management requests
2141 	 */
2142 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++)
2143 		cm->rx_buf[i] = NULL;
2144 
2145 	cm->rx_slots = RIOCM_RX_RING_SIZE;
2146 	mutex_init(&cm->rx_lock);
2147 	riocm_rx_fill(cm, RIOCM_RX_RING_SIZE);
2148 	INIT_WORK(&cm->rx_work, rio_ibmsg_handler);
2149 
2150 	cm->tx_slot = 0;
2151 	cm->tx_cnt = 0;
2152 	cm->tx_ack_slot = 0;
2153 	spin_lock_init(&cm->tx_lock);
2154 
2155 	INIT_LIST_HEAD(&cm->peers);
2156 	cm->npeers = 0;
2157 	INIT_LIST_HEAD(&cm->tx_reqs);
2158 
2159 	down_write(&rdev_sem);
2160 	list_add_tail(&cm->list, &cm_dev_list);
2161 	up_write(&rdev_sem);
2162 
2163 	return 0;
2164 }
2165 
2166 /*
2167  * riocm_remove_mport - remove local mport device from channel management core
2168  * @dev: device object associated with mport
2169  *
2170  * Removes a local mport device from the list of registered devices that provide
2171  * channel management services. Returns an error if the specified mport is not
2172  * registered with the CM core.
2173  */
2174 static void riocm_remove_mport(struct device *dev)
2175 {
2176 	struct rio_mport *mport = to_rio_mport(dev);
2177 	struct cm_dev *cm;
2178 	struct cm_peer *peer, *temp;
2179 	struct rio_channel *ch, *_c;
2180 	unsigned int i;
2181 	bool found = false;
2182 	LIST_HEAD(list);
2183 
2184 	riocm_debug(MPORT, "%s", mport->name);
2185 
2186 	/* Find a matching cm_dev object */
2187 	down_write(&rdev_sem);
2188 	list_for_each_entry(cm, &cm_dev_list, list) {
2189 		if (cm->mport == mport) {
2190 			list_del(&cm->list);
2191 			found = true;
2192 			break;
2193 		}
2194 	}
2195 	up_write(&rdev_sem);
2196 	if (!found)
2197 		return;
2198 
2199 	flush_workqueue(cm->rx_wq);
2200 	destroy_workqueue(cm->rx_wq);
2201 
2202 	/* Release channels bound to this mport */
2203 	spin_lock_bh(&idr_lock);
2204 	idr_for_each_entry(&ch_idr, ch, i) {
2205 		if (ch->cmdev == cm) {
2206 			riocm_debug(RDEV, "%s drop ch_%d",
2207 				    mport->name, ch->id);
2208 			idr_remove(&ch_idr, ch->id);
2209 			list_add(&ch->ch_node, &list);
2210 		}
2211 	}
2212 	spin_unlock_bh(&idr_lock);
2213 
2214 	if (!list_empty(&list)) {
2215 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
2216 			list_del(&ch->ch_node);
2217 			riocm_ch_close(ch);
2218 		}
2219 	}
2220 
2221 	rio_release_inb_mbox(mport, cmbox);
2222 	rio_release_outb_mbox(mport, cmbox);
2223 
2224 	/* Remove and free peer entries */
2225 	if (!list_empty(&cm->peers))
2226 		riocm_debug(RDEV, "ATTN: peer list not empty");
2227 	list_for_each_entry_safe(peer, temp, &cm->peers, node) {
2228 		riocm_debug(RDEV, "removing peer %s", rio_name(peer->rdev));
2229 		list_del(&peer->node);
2230 		kfree(peer);
2231 	}
2232 
2233 	riocm_rx_free(cm);
2234 	kfree(cm);
2235 	riocm_debug(MPORT, "%s done", mport->name);
2236 }
2237 
2238 static int rio_cm_shutdown(struct notifier_block *nb, unsigned long code,
2239 	void *unused)
2240 {
2241 	struct rio_channel *ch;
2242 	unsigned int i;
2243 	LIST_HEAD(list);
2244 
2245 	riocm_debug(EXIT, ".");
2246 
2247 	/*
2248 	 * If there are any channels left in connected state send
2249 	 * close notification to the connection partner.
2250 	 * First build a list of channels that require a closing
2251 	 * notification because function riocm_send_close() should
2252 	 * be called outside of spinlock protected code.
2253 	 */
2254 	spin_lock_bh(&idr_lock);
2255 	idr_for_each_entry(&ch_idr, ch, i) {
2256 		if (ch->state == RIO_CM_CONNECTED) {
2257 			riocm_debug(EXIT, "close ch %d", ch->id);
2258 			idr_remove(&ch_idr, ch->id);
2259 			list_add(&ch->ch_node, &list);
2260 		}
2261 	}
2262 	spin_unlock_bh(&idr_lock);
2263 
2264 	list_for_each_entry(ch, &list, ch_node)
2265 		riocm_send_close(ch);
2266 
2267 	return NOTIFY_DONE;
2268 }
2269 
2270 /*
2271  * riocm_interface handles addition/removal of remote RapidIO devices
2272  */
2273 static struct subsys_interface riocm_interface = {
2274 	.name		= "rio_cm",
2275 	.subsys		= &rio_bus_type,
2276 	.add_dev	= riocm_add_dev,
2277 	.remove_dev	= riocm_remove_dev,
2278 };
2279 
2280 /*
2281  * rio_mport_interface handles addition/removal local mport devices
2282  */
2283 static struct class_interface rio_mport_interface __refdata = {
2284 	.class = &rio_mport_class,
2285 	.add_dev = riocm_add_mport,
2286 	.remove_dev = riocm_remove_mport,
2287 };
2288 
2289 static struct notifier_block rio_cm_notifier = {
2290 	.notifier_call = rio_cm_shutdown,
2291 };
2292 
2293 static int __init riocm_init(void)
2294 {
2295 	int ret;
2296 
2297 	/* Create device class needed by udev */
2298 	ret = class_register(&dev_class);
2299 	if (ret) {
2300 		riocm_error("Cannot create " DRV_NAME " class");
2301 		return ret;
2302 	}
2303 
2304 	ret = alloc_chrdev_region(&dev_number, 0, 1, DRV_NAME);
2305 	if (ret) {
2306 		class_unregister(&dev_class);
2307 		return ret;
2308 	}
2309 
2310 	dev_major = MAJOR(dev_number);
2311 	dev_minor_base = MINOR(dev_number);
2312 	riocm_debug(INIT, "Registered class with %d major", dev_major);
2313 
2314 	/*
2315 	 * Register as rapidio_port class interface to get notifications about
2316 	 * mport additions and removals.
2317 	 */
2318 	ret = class_interface_register(&rio_mport_interface);
2319 	if (ret) {
2320 		riocm_error("class_interface_register error: %d", ret);
2321 		goto err_reg;
2322 	}
2323 
2324 	/*
2325 	 * Register as RapidIO bus interface to get notifications about
2326 	 * addition/removal of remote RapidIO devices.
2327 	 */
2328 	ret = subsys_interface_register(&riocm_interface);
2329 	if (ret) {
2330 		riocm_error("subsys_interface_register error: %d", ret);
2331 		goto err_cl;
2332 	}
2333 
2334 	ret = register_reboot_notifier(&rio_cm_notifier);
2335 	if (ret) {
2336 		riocm_error("failed to register reboot notifier (err=%d)", ret);
2337 		goto err_sif;
2338 	}
2339 
2340 	ret = riocm_cdev_add(dev_number);
2341 	if (ret) {
2342 		unregister_reboot_notifier(&rio_cm_notifier);
2343 		ret = -ENODEV;
2344 		goto err_sif;
2345 	}
2346 
2347 	return 0;
2348 err_sif:
2349 	subsys_interface_unregister(&riocm_interface);
2350 err_cl:
2351 	class_interface_unregister(&rio_mport_interface);
2352 err_reg:
2353 	unregister_chrdev_region(dev_number, 1);
2354 	class_unregister(&dev_class);
2355 	return ret;
2356 }
2357 
2358 static void __exit riocm_exit(void)
2359 {
2360 	riocm_debug(EXIT, "enter");
2361 	unregister_reboot_notifier(&rio_cm_notifier);
2362 	subsys_interface_unregister(&riocm_interface);
2363 	class_interface_unregister(&rio_mport_interface);
2364 	idr_destroy(&ch_idr);
2365 
2366 	device_unregister(riocm_cdev.dev);
2367 	cdev_del(&(riocm_cdev.cdev));
2368 
2369 	class_unregister(&dev_class);
2370 	unregister_chrdev_region(dev_number, 1);
2371 }
2372 
2373 late_initcall(riocm_init);
2374 module_exit(riocm_exit);
2375