xref: /linux/drivers/rapidio/rio_cm.c (revision 561add0da6d3d07c9bccb0832fb6ed5619167d26)
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 struct class *dev_class;
237 static unsigned int dev_major;
238 static unsigned int dev_minor_base;
239 static dev_t dev_number;
240 static struct channel_dev riocm_cdev;
241 
242 #define is_msg_capable(src_ops, dst_ops)			\
243 			((src_ops & RIO_SRC_OPS_DATA_MSG) &&	\
244 			 (dst_ops & RIO_DST_OPS_DATA_MSG))
245 #define dev_cm_capable(dev) \
246 	is_msg_capable(dev->src_ops, dev->dst_ops)
247 
248 static int riocm_cmp(struct rio_channel *ch, enum rio_cm_state cmp)
249 {
250 	int ret;
251 
252 	spin_lock_bh(&ch->lock);
253 	ret = (ch->state == cmp);
254 	spin_unlock_bh(&ch->lock);
255 	return ret;
256 }
257 
258 static int riocm_cmp_exch(struct rio_channel *ch,
259 			   enum rio_cm_state cmp, enum rio_cm_state exch)
260 {
261 	int ret;
262 
263 	spin_lock_bh(&ch->lock);
264 	ret = (ch->state == cmp);
265 	if (ret)
266 		ch->state = exch;
267 	spin_unlock_bh(&ch->lock);
268 	return ret;
269 }
270 
271 static enum rio_cm_state riocm_exch(struct rio_channel *ch,
272 				    enum rio_cm_state exch)
273 {
274 	enum rio_cm_state old;
275 
276 	spin_lock_bh(&ch->lock);
277 	old = ch->state;
278 	ch->state = exch;
279 	spin_unlock_bh(&ch->lock);
280 	return old;
281 }
282 
283 static struct rio_channel *riocm_get_channel(u16 nr)
284 {
285 	struct rio_channel *ch;
286 
287 	spin_lock_bh(&idr_lock);
288 	ch = idr_find(&ch_idr, nr);
289 	if (ch)
290 		kref_get(&ch->ref);
291 	spin_unlock_bh(&idr_lock);
292 	return ch;
293 }
294 
295 static void riocm_put_channel(struct rio_channel *ch)
296 {
297 	kref_put(&ch->ref, riocm_ch_free);
298 }
299 
300 static void *riocm_rx_get_msg(struct cm_dev *cm)
301 {
302 	void *msg;
303 	int i;
304 
305 	msg = rio_get_inb_message(cm->mport, cmbox);
306 	if (msg) {
307 		for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
308 			if (cm->rx_buf[i] == msg) {
309 				cm->rx_buf[i] = NULL;
310 				cm->rx_slots++;
311 				break;
312 			}
313 		}
314 
315 		if (i == RIOCM_RX_RING_SIZE)
316 			riocm_warn("no record for buffer 0x%p", msg);
317 	}
318 
319 	return msg;
320 }
321 
322 /*
323  * riocm_rx_fill - fills a ring of receive buffers for given cm device
324  * @cm: cm_dev object
325  * @nent: max number of entries to fill
326  *
327  * Returns: none
328  */
329 static void riocm_rx_fill(struct cm_dev *cm, int nent)
330 {
331 	int i;
332 
333 	if (cm->rx_slots == 0)
334 		return;
335 
336 	for (i = 0; i < RIOCM_RX_RING_SIZE && cm->rx_slots && nent; i++) {
337 		if (cm->rx_buf[i] == NULL) {
338 			cm->rx_buf[i] = kmalloc(RIO_MAX_MSG_SIZE, GFP_KERNEL);
339 			if (cm->rx_buf[i] == NULL)
340 				break;
341 			rio_add_inb_buffer(cm->mport, cmbox, cm->rx_buf[i]);
342 			cm->rx_slots--;
343 			nent--;
344 		}
345 	}
346 }
347 
348 /*
349  * riocm_rx_free - frees all receive buffers associated with given cm device
350  * @cm: cm_dev object
351  *
352  * Returns: none
353  */
354 static void riocm_rx_free(struct cm_dev *cm)
355 {
356 	int i;
357 
358 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
359 		if (cm->rx_buf[i] != NULL) {
360 			kfree(cm->rx_buf[i]);
361 			cm->rx_buf[i] = NULL;
362 		}
363 	}
364 }
365 
366 /*
367  * riocm_req_handler - connection request handler
368  * @cm: cm_dev object
369  * @req_data: pointer to the request packet
370  *
371  * Returns: 0 if success, or
372  *          -EINVAL if channel is not in correct state,
373  *          -ENODEV if cannot find a channel with specified ID,
374  *          -ENOMEM if unable to allocate memory to store the request
375  */
376 static int riocm_req_handler(struct cm_dev *cm, void *req_data)
377 {
378 	struct rio_channel *ch;
379 	struct conn_req *req;
380 	struct rio_ch_chan_hdr *hh = req_data;
381 	u16 chnum;
382 
383 	chnum = ntohs(hh->dst_ch);
384 
385 	ch = riocm_get_channel(chnum);
386 
387 	if (!ch)
388 		return -ENODEV;
389 
390 	if (ch->state != RIO_CM_LISTEN) {
391 		riocm_debug(RX_CMD, "channel %d is not in listen state", chnum);
392 		riocm_put_channel(ch);
393 		return -EINVAL;
394 	}
395 
396 	req = kzalloc(sizeof(*req), GFP_KERNEL);
397 	if (!req) {
398 		riocm_put_channel(ch);
399 		return -ENOMEM;
400 	}
401 
402 	req->destid = ntohl(hh->bhdr.src_id);
403 	req->chan = ntohs(hh->src_ch);
404 	req->cmdev = cm;
405 
406 	spin_lock_bh(&ch->lock);
407 	list_add_tail(&req->node, &ch->accept_queue);
408 	spin_unlock_bh(&ch->lock);
409 	complete(&ch->comp);
410 	riocm_put_channel(ch);
411 
412 	return 0;
413 }
414 
415 /*
416  * riocm_resp_handler - response to connection request handler
417  * @resp_data: pointer to the response packet
418  *
419  * Returns: 0 if success, or
420  *          -EINVAL if channel is not in correct state,
421  *          -ENODEV if cannot find a channel with specified ID,
422  */
423 static int riocm_resp_handler(void *resp_data)
424 {
425 	struct rio_channel *ch;
426 	struct rio_ch_chan_hdr *hh = resp_data;
427 	u16 chnum;
428 
429 	chnum = ntohs(hh->dst_ch);
430 	ch = riocm_get_channel(chnum);
431 	if (!ch)
432 		return -ENODEV;
433 
434 	if (ch->state != RIO_CM_CONNECT) {
435 		riocm_put_channel(ch);
436 		return -EINVAL;
437 	}
438 
439 	riocm_exch(ch, RIO_CM_CONNECTED);
440 	ch->rem_channel = ntohs(hh->src_ch);
441 	complete(&ch->comp);
442 	riocm_put_channel(ch);
443 
444 	return 0;
445 }
446 
447 /*
448  * riocm_close_handler - channel close request handler
449  * @req_data: pointer to the request packet
450  *
451  * Returns: 0 if success, or
452  *          -ENODEV if cannot find a channel with specified ID,
453  *            + error codes returned by riocm_ch_close.
454  */
455 static int riocm_close_handler(void *data)
456 {
457 	struct rio_channel *ch;
458 	struct rio_ch_chan_hdr *hh = data;
459 	int ret;
460 
461 	riocm_debug(RX_CMD, "for ch=%d", ntohs(hh->dst_ch));
462 
463 	spin_lock_bh(&idr_lock);
464 	ch = idr_find(&ch_idr, ntohs(hh->dst_ch));
465 	if (!ch) {
466 		spin_unlock_bh(&idr_lock);
467 		return -ENODEV;
468 	}
469 	idr_remove(&ch_idr, ch->id);
470 	spin_unlock_bh(&idr_lock);
471 
472 	riocm_exch(ch, RIO_CM_DISCONNECT);
473 
474 	ret = riocm_ch_close(ch);
475 	if (ret)
476 		riocm_debug(RX_CMD, "riocm_ch_close() returned %d", ret);
477 
478 	return 0;
479 }
480 
481 /*
482  * rio_cm_handler - function that services request (non-data) packets
483  * @cm: cm_dev object
484  * @data: pointer to the packet
485  */
486 static void rio_cm_handler(struct cm_dev *cm, void *data)
487 {
488 	struct rio_ch_chan_hdr *hdr;
489 
490 	if (!rio_mport_is_running(cm->mport))
491 		goto out;
492 
493 	hdr = data;
494 
495 	riocm_debug(RX_CMD, "OP=%x for ch=%d from %d",
496 		    hdr->ch_op, ntohs(hdr->dst_ch), ntohs(hdr->src_ch));
497 
498 	switch (hdr->ch_op) {
499 	case CM_CONN_REQ:
500 		riocm_req_handler(cm, data);
501 		break;
502 	case CM_CONN_ACK:
503 		riocm_resp_handler(data);
504 		break;
505 	case CM_CONN_CLOSE:
506 		riocm_close_handler(data);
507 		break;
508 	default:
509 		riocm_error("Invalid packet header");
510 		break;
511 	}
512 out:
513 	kfree(data);
514 }
515 
516 /*
517  * rio_rx_data_handler - received data packet handler
518  * @cm: cm_dev object
519  * @buf: data packet
520  *
521  * Returns: 0 if success, or
522  *          -ENODEV if cannot find a channel with specified ID,
523  *          -EIO if channel is not in CONNECTED state,
524  *          -ENOMEM if channel RX queue is full (packet discarded)
525  */
526 static int rio_rx_data_handler(struct cm_dev *cm, void *buf)
527 {
528 	struct rio_ch_chan_hdr *hdr;
529 	struct rio_channel *ch;
530 
531 	hdr = buf;
532 
533 	riocm_debug(RX_DATA, "for ch=%d", ntohs(hdr->dst_ch));
534 
535 	ch = riocm_get_channel(ntohs(hdr->dst_ch));
536 	if (!ch) {
537 		/* Discard data message for non-existing channel */
538 		kfree(buf);
539 		return -ENODEV;
540 	}
541 
542 	/* Place pointer to the buffer into channel's RX queue */
543 	spin_lock(&ch->lock);
544 
545 	if (ch->state != RIO_CM_CONNECTED) {
546 		/* Channel is not ready to receive data, discard a packet */
547 		riocm_debug(RX_DATA, "ch=%d is in wrong state=%d",
548 			    ch->id, ch->state);
549 		spin_unlock(&ch->lock);
550 		kfree(buf);
551 		riocm_put_channel(ch);
552 		return -EIO;
553 	}
554 
555 	if (ch->rx_ring.count == RIOCM_RX_RING_SIZE) {
556 		/* If RX ring is full, discard a packet */
557 		riocm_debug(RX_DATA, "ch=%d is full", ch->id);
558 		spin_unlock(&ch->lock);
559 		kfree(buf);
560 		riocm_put_channel(ch);
561 		return -ENOMEM;
562 	}
563 
564 	ch->rx_ring.buf[ch->rx_ring.head] = buf;
565 	ch->rx_ring.head++;
566 	ch->rx_ring.count++;
567 	ch->rx_ring.head %= RIOCM_RX_RING_SIZE;
568 
569 	complete(&ch->comp);
570 
571 	spin_unlock(&ch->lock);
572 	riocm_put_channel(ch);
573 
574 	return 0;
575 }
576 
577 /*
578  * rio_ibmsg_handler - inbound message packet handler
579  */
580 static void rio_ibmsg_handler(struct work_struct *work)
581 {
582 	struct cm_dev *cm = container_of(work, struct cm_dev, rx_work);
583 	void *data;
584 	struct rio_ch_chan_hdr *hdr;
585 
586 	if (!rio_mport_is_running(cm->mport))
587 		return;
588 
589 	while (1) {
590 		mutex_lock(&cm->rx_lock);
591 		data = riocm_rx_get_msg(cm);
592 		if (data)
593 			riocm_rx_fill(cm, 1);
594 		mutex_unlock(&cm->rx_lock);
595 
596 		if (data == NULL)
597 			break;
598 
599 		hdr = data;
600 
601 		if (hdr->bhdr.type != RIO_CM_CHAN) {
602 			/* For now simply discard packets other than channel */
603 			riocm_error("Unsupported TYPE code (0x%x). Msg dropped",
604 				    hdr->bhdr.type);
605 			kfree(data);
606 			continue;
607 		}
608 
609 		/* Process a channel message */
610 		if (hdr->ch_op == CM_DATA_MSG)
611 			rio_rx_data_handler(cm, data);
612 		else
613 			rio_cm_handler(cm, data);
614 	}
615 }
616 
617 static void riocm_inb_msg_event(struct rio_mport *mport, void *dev_id,
618 				int mbox, int slot)
619 {
620 	struct cm_dev *cm = dev_id;
621 
622 	if (rio_mport_is_running(cm->mport) && !work_pending(&cm->rx_work))
623 		queue_work(cm->rx_wq, &cm->rx_work);
624 }
625 
626 /*
627  * rio_txcq_handler - TX completion handler
628  * @cm: cm_dev object
629  * @slot: TX queue slot
630  *
631  * TX completion handler also ensures that pending request packets are placed
632  * into transmit queue as soon as a free slot becomes available. This is done
633  * to give higher priority to request packets during high intensity data flow.
634  */
635 static void rio_txcq_handler(struct cm_dev *cm, int slot)
636 {
637 	int ack_slot;
638 
639 	/* ATTN: Add TX completion notification if/when direct buffer
640 	 * transfer is implemented. At this moment only correct tracking
641 	 * of tx_count is important.
642 	 */
643 	riocm_debug(TX_EVENT, "for mport_%d slot %d tx_cnt %d",
644 		    cm->mport->id, slot, cm->tx_cnt);
645 
646 	spin_lock(&cm->tx_lock);
647 	ack_slot = cm->tx_ack_slot;
648 
649 	if (ack_slot == slot)
650 		riocm_debug(TX_EVENT, "slot == ack_slot");
651 
652 	while (cm->tx_cnt && ((ack_slot != slot) ||
653 	       (cm->tx_cnt == RIOCM_TX_RING_SIZE))) {
654 
655 		cm->tx_buf[ack_slot] = NULL;
656 		++ack_slot;
657 		ack_slot &= (RIOCM_TX_RING_SIZE - 1);
658 		cm->tx_cnt--;
659 	}
660 
661 	if (cm->tx_cnt < 0 || cm->tx_cnt > RIOCM_TX_RING_SIZE)
662 		riocm_error("tx_cnt %d out of sync", cm->tx_cnt);
663 
664 	WARN_ON((cm->tx_cnt < 0) || (cm->tx_cnt > RIOCM_TX_RING_SIZE));
665 
666 	cm->tx_ack_slot = ack_slot;
667 
668 	/*
669 	 * If there are pending requests, insert them into transmit queue
670 	 */
671 	if (!list_empty(&cm->tx_reqs) && (cm->tx_cnt < RIOCM_TX_RING_SIZE)) {
672 		struct tx_req *req, *_req;
673 		int rc;
674 
675 		list_for_each_entry_safe(req, _req, &cm->tx_reqs, node) {
676 			list_del(&req->node);
677 			cm->tx_buf[cm->tx_slot] = req->buffer;
678 			rc = rio_add_outb_message(cm->mport, req->rdev, cmbox,
679 						  req->buffer, req->len);
680 			kfree(req->buffer);
681 			kfree(req);
682 
683 			++cm->tx_cnt;
684 			++cm->tx_slot;
685 			cm->tx_slot &= (RIOCM_TX_RING_SIZE - 1);
686 			if (cm->tx_cnt == RIOCM_TX_RING_SIZE)
687 				break;
688 		}
689 	}
690 
691 	spin_unlock(&cm->tx_lock);
692 }
693 
694 static void riocm_outb_msg_event(struct rio_mport *mport, void *dev_id,
695 				 int mbox, int slot)
696 {
697 	struct cm_dev *cm = dev_id;
698 
699 	if (cm && rio_mport_is_running(cm->mport))
700 		rio_txcq_handler(cm, slot);
701 }
702 
703 static int riocm_queue_req(struct cm_dev *cm, struct rio_dev *rdev,
704 			   void *buffer, size_t len)
705 {
706 	unsigned long flags;
707 	struct tx_req *treq;
708 
709 	treq = kzalloc(sizeof(*treq), GFP_KERNEL);
710 	if (treq == NULL)
711 		return -ENOMEM;
712 
713 	treq->rdev = rdev;
714 	treq->buffer = buffer;
715 	treq->len = len;
716 
717 	spin_lock_irqsave(&cm->tx_lock, flags);
718 	list_add_tail(&treq->node, &cm->tx_reqs);
719 	spin_unlock_irqrestore(&cm->tx_lock, flags);
720 	return 0;
721 }
722 
723 /*
724  * riocm_post_send - helper function that places packet into msg TX queue
725  * @cm: cm_dev object
726  * @rdev: target RapidIO device object (required by outbound msg interface)
727  * @buffer: pointer to a packet buffer to send
728  * @len: length of data to transfer
729  * @req: request priority flag
730  *
731  * Returns: 0 if success, or error code otherwise.
732  */
733 static int riocm_post_send(struct cm_dev *cm, struct rio_dev *rdev,
734 			   void *buffer, size_t len)
735 {
736 	int rc;
737 	unsigned long flags;
738 
739 	spin_lock_irqsave(&cm->tx_lock, flags);
740 
741 	if (cm->mport == NULL) {
742 		rc = -ENODEV;
743 		goto err_out;
744 	}
745 
746 	if (cm->tx_cnt == RIOCM_TX_RING_SIZE) {
747 		riocm_debug(TX, "Tx Queue is full");
748 		rc = -EBUSY;
749 		goto err_out;
750 	}
751 
752 	cm->tx_buf[cm->tx_slot] = buffer;
753 	rc = rio_add_outb_message(cm->mport, rdev, cmbox, buffer, len);
754 
755 	riocm_debug(TX, "Add buf@%p destid=%x tx_slot=%d tx_cnt=%d",
756 		 buffer, rdev->destid, cm->tx_slot, cm->tx_cnt);
757 
758 	++cm->tx_cnt;
759 	++cm->tx_slot;
760 	cm->tx_slot &= (RIOCM_TX_RING_SIZE - 1);
761 
762 err_out:
763 	spin_unlock_irqrestore(&cm->tx_lock, flags);
764 	return rc;
765 }
766 
767 /*
768  * riocm_ch_send - sends a data packet to a remote device
769  * @ch_id: local channel ID
770  * @buf: pointer to a data buffer to send (including CM header)
771  * @len: length of data to transfer (including CM header)
772  *
773  * ATTN: ASSUMES THAT THE HEADER SPACE IS RESERVED PART OF THE DATA PACKET
774  *
775  * Returns: 0 if success, or
776  *          -EINVAL if one or more input parameters is/are not valid,
777  *          -ENODEV if cannot find a channel with specified ID,
778  *          -EAGAIN if a channel is not in CONNECTED state,
779  *	    + error codes returned by HW send routine.
780  */
781 static int riocm_ch_send(u16 ch_id, void *buf, int len)
782 {
783 	struct rio_channel *ch;
784 	struct rio_ch_chan_hdr *hdr;
785 	int ret;
786 
787 	if (buf == NULL || ch_id == 0 || len == 0 || len > RIO_MAX_MSG_SIZE)
788 		return -EINVAL;
789 
790 	ch = riocm_get_channel(ch_id);
791 	if (!ch) {
792 		riocm_error("%s(%d) ch_%d not found", current->comm,
793 			    task_pid_nr(current), ch_id);
794 		return -ENODEV;
795 	}
796 
797 	if (!riocm_cmp(ch, RIO_CM_CONNECTED)) {
798 		ret = -EAGAIN;
799 		goto err_out;
800 	}
801 
802 	/*
803 	 * Fill buffer header section with corresponding channel data
804 	 */
805 	hdr = buf;
806 
807 	hdr->bhdr.src_id = htonl(ch->loc_destid);
808 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
809 	hdr->bhdr.src_mbox = cmbox;
810 	hdr->bhdr.dst_mbox = cmbox;
811 	hdr->bhdr.type = RIO_CM_CHAN;
812 	hdr->ch_op = CM_DATA_MSG;
813 	hdr->dst_ch = htons(ch->rem_channel);
814 	hdr->src_ch = htons(ch->id);
815 	hdr->msg_len = htons((u16)len);
816 
817 	/* ATTN: the function call below relies on the fact that underlying
818 	 * HW-specific add_outb_message() routine copies TX data into its own
819 	 * internal transfer buffer (true for all RIONET compatible mport
820 	 * drivers). Must be reviewed if mport driver uses the buffer directly.
821 	 */
822 
823 	ret = riocm_post_send(ch->cmdev, ch->rdev, buf, len);
824 	if (ret)
825 		riocm_debug(TX, "ch %d send_err=%d", ch->id, ret);
826 err_out:
827 	riocm_put_channel(ch);
828 	return ret;
829 }
830 
831 static int riocm_ch_free_rxbuf(struct rio_channel *ch, void *buf)
832 {
833 	int i, ret = -EINVAL;
834 
835 	spin_lock_bh(&ch->lock);
836 
837 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
838 		if (ch->rx_ring.inuse[i] == buf) {
839 			ch->rx_ring.inuse[i] = NULL;
840 			ch->rx_ring.inuse_cnt--;
841 			ret = 0;
842 			break;
843 		}
844 	}
845 
846 	spin_unlock_bh(&ch->lock);
847 
848 	if (!ret)
849 		kfree(buf);
850 
851 	return ret;
852 }
853 
854 /*
855  * riocm_ch_receive - fetch a data packet received for the specified channel
856  * @ch: local channel ID
857  * @buf: pointer to a packet buffer
858  * @timeout: timeout to wait for incoming packet (in jiffies)
859  *
860  * Returns: 0 and valid buffer pointer if success, or NULL pointer and one of:
861  *          -EAGAIN if a channel is not in CONNECTED state,
862  *          -ENOMEM if in-use tracking queue is full,
863  *          -ETIME if wait timeout expired,
864  *	    -EINTR if wait was interrupted.
865  */
866 static int riocm_ch_receive(struct rio_channel *ch, void **buf, long timeout)
867 {
868 	void *rxmsg = NULL;
869 	int i, ret = 0;
870 	long wret;
871 
872 	if (!riocm_cmp(ch, RIO_CM_CONNECTED)) {
873 		ret = -EAGAIN;
874 		goto out;
875 	}
876 
877 	if (ch->rx_ring.inuse_cnt == RIOCM_RX_RING_SIZE) {
878 		/* If we do not have entries to track buffers given to upper
879 		 * layer, reject request.
880 		 */
881 		ret = -ENOMEM;
882 		goto out;
883 	}
884 
885 	wret = wait_for_completion_interruptible_timeout(&ch->comp, timeout);
886 
887 	riocm_debug(WAIT, "wait on %d returned %ld", ch->id, wret);
888 
889 	if (!wret)
890 		ret = -ETIME;
891 	else if (wret == -ERESTARTSYS)
892 		ret = -EINTR;
893 	else
894 		ret = riocm_cmp(ch, RIO_CM_CONNECTED) ? 0 : -ECONNRESET;
895 
896 	if (ret)
897 		goto out;
898 
899 	spin_lock_bh(&ch->lock);
900 
901 	rxmsg = ch->rx_ring.buf[ch->rx_ring.tail];
902 	ch->rx_ring.buf[ch->rx_ring.tail] = NULL;
903 	ch->rx_ring.count--;
904 	ch->rx_ring.tail++;
905 	ch->rx_ring.tail %= RIOCM_RX_RING_SIZE;
906 	ret = -ENOMEM;
907 
908 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++) {
909 		if (ch->rx_ring.inuse[i] == NULL) {
910 			ch->rx_ring.inuse[i] = rxmsg;
911 			ch->rx_ring.inuse_cnt++;
912 			ret = 0;
913 			break;
914 		}
915 	}
916 
917 	if (ret) {
918 		/* We have no entry to store pending message: drop it */
919 		kfree(rxmsg);
920 		rxmsg = NULL;
921 	}
922 
923 	spin_unlock_bh(&ch->lock);
924 out:
925 	*buf = rxmsg;
926 	return ret;
927 }
928 
929 /*
930  * riocm_ch_connect - sends a connect request to a remote device
931  * @loc_ch: local channel ID
932  * @cm: CM device to send connect request
933  * @peer: target RapidIO device
934  * @rem_ch: remote channel ID
935  *
936  * Returns: 0 if success, or
937  *          -EINVAL if the channel is not in IDLE state,
938  *          -EAGAIN if no connection request available immediately,
939  *          -ETIME if ACK response timeout expired,
940  *          -EINTR if wait for response was interrupted.
941  */
942 static int riocm_ch_connect(u16 loc_ch, struct cm_dev *cm,
943 			    struct cm_peer *peer, u16 rem_ch)
944 {
945 	struct rio_channel *ch = NULL;
946 	struct rio_ch_chan_hdr *hdr;
947 	int ret;
948 	long wret;
949 
950 	ch = riocm_get_channel(loc_ch);
951 	if (!ch)
952 		return -ENODEV;
953 
954 	if (!riocm_cmp_exch(ch, RIO_CM_IDLE, RIO_CM_CONNECT)) {
955 		ret = -EINVAL;
956 		goto conn_done;
957 	}
958 
959 	ch->cmdev = cm;
960 	ch->rdev = peer->rdev;
961 	ch->context = NULL;
962 	ch->loc_destid = cm->mport->host_deviceid;
963 	ch->rem_channel = rem_ch;
964 
965 	/*
966 	 * Send connect request to the remote RapidIO device
967 	 */
968 
969 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
970 	if (hdr == NULL) {
971 		ret = -ENOMEM;
972 		goto conn_done;
973 	}
974 
975 	hdr->bhdr.src_id = htonl(ch->loc_destid);
976 	hdr->bhdr.dst_id = htonl(peer->rdev->destid);
977 	hdr->bhdr.src_mbox = cmbox;
978 	hdr->bhdr.dst_mbox = cmbox;
979 	hdr->bhdr.type = RIO_CM_CHAN;
980 	hdr->ch_op = CM_CONN_REQ;
981 	hdr->dst_ch = htons(rem_ch);
982 	hdr->src_ch = htons(loc_ch);
983 
984 	/* ATTN: the function call below relies on the fact that underlying
985 	 * HW-specific add_outb_message() routine copies TX data into its
986 	 * internal transfer buffer. Must be reviewed if mport driver uses
987 	 * this buffer directly.
988 	 */
989 	ret = riocm_post_send(cm, peer->rdev, hdr, sizeof(*hdr));
990 
991 	if (ret != -EBUSY) {
992 		kfree(hdr);
993 	} else {
994 		ret = riocm_queue_req(cm, peer->rdev, hdr, sizeof(*hdr));
995 		if (ret)
996 			kfree(hdr);
997 	}
998 
999 	if (ret) {
1000 		riocm_cmp_exch(ch, RIO_CM_CONNECT, RIO_CM_IDLE);
1001 		goto conn_done;
1002 	}
1003 
1004 	/* Wait for connect response from the remote device */
1005 	wret = wait_for_completion_interruptible_timeout(&ch->comp,
1006 							 RIOCM_CONNECT_TO * HZ);
1007 	riocm_debug(WAIT, "wait on %d returns %ld", ch->id, wret);
1008 
1009 	if (!wret)
1010 		ret = -ETIME;
1011 	else if (wret == -ERESTARTSYS)
1012 		ret = -EINTR;
1013 	else
1014 		ret = riocm_cmp(ch, RIO_CM_CONNECTED) ? 0 : -1;
1015 
1016 conn_done:
1017 	riocm_put_channel(ch);
1018 	return ret;
1019 }
1020 
1021 static int riocm_send_ack(struct rio_channel *ch)
1022 {
1023 	struct rio_ch_chan_hdr *hdr;
1024 	int ret;
1025 
1026 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
1027 	if (hdr == NULL)
1028 		return -ENOMEM;
1029 
1030 	hdr->bhdr.src_id = htonl(ch->loc_destid);
1031 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
1032 	hdr->dst_ch = htons(ch->rem_channel);
1033 	hdr->src_ch = htons(ch->id);
1034 	hdr->bhdr.src_mbox = cmbox;
1035 	hdr->bhdr.dst_mbox = cmbox;
1036 	hdr->bhdr.type = RIO_CM_CHAN;
1037 	hdr->ch_op = CM_CONN_ACK;
1038 
1039 	/* ATTN: the function call below relies on the fact that underlying
1040 	 * add_outb_message() routine copies TX data into its internal transfer
1041 	 * buffer. Review if switching to direct buffer version.
1042 	 */
1043 	ret = riocm_post_send(ch->cmdev, ch->rdev, hdr, sizeof(*hdr));
1044 
1045 	if (ret == -EBUSY && !riocm_queue_req(ch->cmdev,
1046 					      ch->rdev, hdr, sizeof(*hdr)))
1047 		return 0;
1048 	kfree(hdr);
1049 
1050 	if (ret)
1051 		riocm_error("send ACK to ch_%d on %s failed (ret=%d)",
1052 			    ch->id, rio_name(ch->rdev), ret);
1053 	return ret;
1054 }
1055 
1056 /*
1057  * riocm_ch_accept - accept incoming connection request
1058  * @ch_id: channel ID
1059  * @new_ch_id: local mport device
1060  * @timeout: wait timeout (if 0 non-blocking call, do not wait if connection
1061  *           request is not available).
1062  *
1063  * Returns: pointer to new channel struct if success, or error-valued pointer:
1064  *          -ENODEV - cannot find specified channel or mport,
1065  *          -EINVAL - the channel is not in IDLE state,
1066  *          -EAGAIN - no connection request available immediately (timeout=0),
1067  *          -ENOMEM - unable to allocate new channel,
1068  *          -ETIME - wait timeout expired,
1069  *          -EINTR - wait was interrupted.
1070  */
1071 static struct rio_channel *riocm_ch_accept(u16 ch_id, u16 *new_ch_id,
1072 					   long timeout)
1073 {
1074 	struct rio_channel *ch;
1075 	struct rio_channel *new_ch;
1076 	struct conn_req *req;
1077 	struct cm_peer *peer;
1078 	int found = 0;
1079 	int err = 0;
1080 	long wret;
1081 
1082 	ch = riocm_get_channel(ch_id);
1083 	if (!ch)
1084 		return ERR_PTR(-EINVAL);
1085 
1086 	if (!riocm_cmp(ch, RIO_CM_LISTEN)) {
1087 		err = -EINVAL;
1088 		goto err_put;
1089 	}
1090 
1091 	/* Don't sleep if this is a non blocking call */
1092 	if (!timeout) {
1093 		if (!try_wait_for_completion(&ch->comp)) {
1094 			err = -EAGAIN;
1095 			goto err_put;
1096 		}
1097 	} else {
1098 		riocm_debug(WAIT, "on %d", ch->id);
1099 
1100 		wret = wait_for_completion_interruptible_timeout(&ch->comp,
1101 								 timeout);
1102 		if (!wret) {
1103 			err = -ETIME;
1104 			goto err_put;
1105 		} else if (wret == -ERESTARTSYS) {
1106 			err = -EINTR;
1107 			goto err_put;
1108 		}
1109 	}
1110 
1111 	spin_lock_bh(&ch->lock);
1112 
1113 	if (ch->state != RIO_CM_LISTEN) {
1114 		err = -ECANCELED;
1115 	} else if (list_empty(&ch->accept_queue)) {
1116 		riocm_debug(WAIT, "on %d accept_queue is empty on completion",
1117 			    ch->id);
1118 		err = -EIO;
1119 	}
1120 
1121 	spin_unlock_bh(&ch->lock);
1122 
1123 	if (err) {
1124 		riocm_debug(WAIT, "on %d returns %d", ch->id, err);
1125 		goto err_put;
1126 	}
1127 
1128 	/* Create new channel for this connection */
1129 	new_ch = riocm_ch_alloc(RIOCM_CHNUM_AUTO);
1130 
1131 	if (IS_ERR(new_ch)) {
1132 		riocm_error("failed to get channel for new req (%ld)",
1133 			PTR_ERR(new_ch));
1134 		err = -ENOMEM;
1135 		goto err_put;
1136 	}
1137 
1138 	spin_lock_bh(&ch->lock);
1139 
1140 	req = list_first_entry(&ch->accept_queue, struct conn_req, node);
1141 	list_del(&req->node);
1142 	new_ch->cmdev = ch->cmdev;
1143 	new_ch->loc_destid = ch->loc_destid;
1144 	new_ch->rem_destid = req->destid;
1145 	new_ch->rem_channel = req->chan;
1146 
1147 	spin_unlock_bh(&ch->lock);
1148 	riocm_put_channel(ch);
1149 	ch = NULL;
1150 	kfree(req);
1151 
1152 	down_read(&rdev_sem);
1153 	/* Find requester's device object */
1154 	list_for_each_entry(peer, &new_ch->cmdev->peers, node) {
1155 		if (peer->rdev->destid == new_ch->rem_destid) {
1156 			riocm_debug(RX_CMD, "found matching device(%s)",
1157 				    rio_name(peer->rdev));
1158 			found = 1;
1159 			break;
1160 		}
1161 	}
1162 	up_read(&rdev_sem);
1163 
1164 	if (!found) {
1165 		/* If peer device object not found, simply ignore the request */
1166 		err = -ENODEV;
1167 		goto err_put_new_ch;
1168 	}
1169 
1170 	new_ch->rdev = peer->rdev;
1171 	new_ch->state = RIO_CM_CONNECTED;
1172 	spin_lock_init(&new_ch->lock);
1173 
1174 	/* Acknowledge the connection request. */
1175 	riocm_send_ack(new_ch);
1176 
1177 	*new_ch_id = new_ch->id;
1178 	return new_ch;
1179 
1180 err_put_new_ch:
1181 	spin_lock_bh(&idr_lock);
1182 	idr_remove(&ch_idr, new_ch->id);
1183 	spin_unlock_bh(&idr_lock);
1184 	riocm_put_channel(new_ch);
1185 
1186 err_put:
1187 	if (ch)
1188 		riocm_put_channel(ch);
1189 	*new_ch_id = 0;
1190 	return ERR_PTR(err);
1191 }
1192 
1193 /*
1194  * riocm_ch_listen - puts a channel into LISTEN state
1195  * @ch_id: channel ID
1196  *
1197  * Returns: 0 if success, or
1198  *          -EINVAL if the specified channel does not exists or
1199  *                  is not in CHAN_BOUND state.
1200  */
1201 static int riocm_ch_listen(u16 ch_id)
1202 {
1203 	struct rio_channel *ch = NULL;
1204 	int ret = 0;
1205 
1206 	riocm_debug(CHOP, "(ch_%d)", ch_id);
1207 
1208 	ch = riocm_get_channel(ch_id);
1209 	if (!ch)
1210 		return -EINVAL;
1211 	if (!riocm_cmp_exch(ch, RIO_CM_CHAN_BOUND, RIO_CM_LISTEN))
1212 		ret = -EINVAL;
1213 	riocm_put_channel(ch);
1214 	return ret;
1215 }
1216 
1217 /*
1218  * riocm_ch_bind - associate a channel object and an mport device
1219  * @ch_id: channel ID
1220  * @mport_id: local mport device ID
1221  * @context: pointer to the additional caller's context
1222  *
1223  * Returns: 0 if success, or
1224  *          -ENODEV if cannot find specified mport,
1225  *          -EINVAL if the specified channel does not exist or
1226  *                  is not in IDLE state.
1227  */
1228 static int riocm_ch_bind(u16 ch_id, u8 mport_id, void *context)
1229 {
1230 	struct rio_channel *ch = NULL;
1231 	struct cm_dev *cm;
1232 	int rc = -ENODEV;
1233 
1234 	riocm_debug(CHOP, "ch_%d to mport_%d", ch_id, mport_id);
1235 
1236 	/* Find matching cm_dev object */
1237 	down_read(&rdev_sem);
1238 	list_for_each_entry(cm, &cm_dev_list, list) {
1239 		if ((cm->mport->id == mport_id) &&
1240 		     rio_mport_is_running(cm->mport)) {
1241 			rc = 0;
1242 			break;
1243 		}
1244 	}
1245 
1246 	if (rc)
1247 		goto exit;
1248 
1249 	ch = riocm_get_channel(ch_id);
1250 	if (!ch) {
1251 		rc = -EINVAL;
1252 		goto exit;
1253 	}
1254 
1255 	spin_lock_bh(&ch->lock);
1256 	if (ch->state != RIO_CM_IDLE) {
1257 		spin_unlock_bh(&ch->lock);
1258 		rc = -EINVAL;
1259 		goto err_put;
1260 	}
1261 
1262 	ch->cmdev = cm;
1263 	ch->loc_destid = cm->mport->host_deviceid;
1264 	ch->context = context;
1265 	ch->state = RIO_CM_CHAN_BOUND;
1266 	spin_unlock_bh(&ch->lock);
1267 err_put:
1268 	riocm_put_channel(ch);
1269 exit:
1270 	up_read(&rdev_sem);
1271 	return rc;
1272 }
1273 
1274 /*
1275  * riocm_ch_alloc - channel object allocation helper routine
1276  * @ch_num: channel ID (1 ... RIOCM_MAX_CHNUM, 0 = automatic)
1277  *
1278  * Return value: pointer to newly created channel object,
1279  *               or error-valued pointer
1280  */
1281 static struct rio_channel *riocm_ch_alloc(u16 ch_num)
1282 {
1283 	int id;
1284 	int start, end;
1285 	struct rio_channel *ch;
1286 
1287 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
1288 	if (!ch)
1289 		return ERR_PTR(-ENOMEM);
1290 
1291 	if (ch_num) {
1292 		/* If requested, try to obtain the specified channel ID */
1293 		start = ch_num;
1294 		end = ch_num + 1;
1295 	} else {
1296 		/* Obtain channel ID from the dynamic allocation range */
1297 		start = chstart;
1298 		end = RIOCM_MAX_CHNUM + 1;
1299 	}
1300 
1301 	idr_preload(GFP_KERNEL);
1302 	spin_lock_bh(&idr_lock);
1303 	id = idr_alloc_cyclic(&ch_idr, ch, start, end, GFP_NOWAIT);
1304 	spin_unlock_bh(&idr_lock);
1305 	idr_preload_end();
1306 
1307 	if (id < 0) {
1308 		kfree(ch);
1309 		return ERR_PTR(id == -ENOSPC ? -EBUSY : id);
1310 	}
1311 
1312 	ch->id = (u16)id;
1313 	ch->state = RIO_CM_IDLE;
1314 	spin_lock_init(&ch->lock);
1315 	INIT_LIST_HEAD(&ch->accept_queue);
1316 	INIT_LIST_HEAD(&ch->ch_node);
1317 	init_completion(&ch->comp);
1318 	init_completion(&ch->comp_close);
1319 	kref_init(&ch->ref);
1320 	ch->rx_ring.head = 0;
1321 	ch->rx_ring.tail = 0;
1322 	ch->rx_ring.count = 0;
1323 	ch->rx_ring.inuse_cnt = 0;
1324 
1325 	return ch;
1326 }
1327 
1328 /*
1329  * riocm_ch_create - creates a new channel object and allocates ID for it
1330  * @ch_num: channel ID (1 ... RIOCM_MAX_CHNUM, 0 = automatic)
1331  *
1332  * Allocates and initializes a new channel object. If the parameter ch_num > 0
1333  * and is within the valid range, riocm_ch_create tries to allocate the
1334  * specified ID for the new channel. If ch_num = 0, channel ID will be assigned
1335  * automatically from the range (chstart ... RIOCM_MAX_CHNUM).
1336  * Module parameter 'chstart' defines start of an ID range available for dynamic
1337  * allocation. Range below 'chstart' is reserved for pre-defined ID numbers.
1338  * Available channel numbers are limited by 16-bit size of channel numbers used
1339  * in the packet header.
1340  *
1341  * Return value: PTR to rio_channel structure if successful (with channel number
1342  *               updated via pointer) or error-valued pointer if error.
1343  */
1344 static struct rio_channel *riocm_ch_create(u16 *ch_num)
1345 {
1346 	struct rio_channel *ch = NULL;
1347 
1348 	ch = riocm_ch_alloc(*ch_num);
1349 
1350 	if (IS_ERR(ch))
1351 		riocm_debug(CHOP, "Failed to allocate channel %d (err=%ld)",
1352 			    *ch_num, PTR_ERR(ch));
1353 	else
1354 		*ch_num = ch->id;
1355 
1356 	return ch;
1357 }
1358 
1359 /*
1360  * riocm_ch_free - channel object release routine
1361  * @ref: pointer to a channel's kref structure
1362  */
1363 static void riocm_ch_free(struct kref *ref)
1364 {
1365 	struct rio_channel *ch = container_of(ref, struct rio_channel, ref);
1366 	int i;
1367 
1368 	riocm_debug(CHOP, "(ch_%d)", ch->id);
1369 
1370 	if (ch->rx_ring.inuse_cnt) {
1371 		for (i = 0;
1372 		     i < RIOCM_RX_RING_SIZE && ch->rx_ring.inuse_cnt; i++) {
1373 			if (ch->rx_ring.inuse[i] != NULL) {
1374 				kfree(ch->rx_ring.inuse[i]);
1375 				ch->rx_ring.inuse_cnt--;
1376 			}
1377 		}
1378 	}
1379 
1380 	if (ch->rx_ring.count)
1381 		for (i = 0; i < RIOCM_RX_RING_SIZE && ch->rx_ring.count; i++) {
1382 			if (ch->rx_ring.buf[i] != NULL) {
1383 				kfree(ch->rx_ring.buf[i]);
1384 				ch->rx_ring.count--;
1385 			}
1386 		}
1387 
1388 	complete(&ch->comp_close);
1389 }
1390 
1391 static int riocm_send_close(struct rio_channel *ch)
1392 {
1393 	struct rio_ch_chan_hdr *hdr;
1394 	int ret;
1395 
1396 	/*
1397 	 * Send CH_CLOSE notification to the remote RapidIO device
1398 	 */
1399 
1400 	hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
1401 	if (hdr == NULL)
1402 		return -ENOMEM;
1403 
1404 	hdr->bhdr.src_id = htonl(ch->loc_destid);
1405 	hdr->bhdr.dst_id = htonl(ch->rem_destid);
1406 	hdr->bhdr.src_mbox = cmbox;
1407 	hdr->bhdr.dst_mbox = cmbox;
1408 	hdr->bhdr.type = RIO_CM_CHAN;
1409 	hdr->ch_op = CM_CONN_CLOSE;
1410 	hdr->dst_ch = htons(ch->rem_channel);
1411 	hdr->src_ch = htons(ch->id);
1412 
1413 	/* ATTN: the function call below relies on the fact that underlying
1414 	 * add_outb_message() routine copies TX data into its internal transfer
1415 	 * buffer. Needs to be reviewed if switched to direct buffer mode.
1416 	 */
1417 	ret = riocm_post_send(ch->cmdev, ch->rdev, hdr, sizeof(*hdr));
1418 
1419 	if (ret == -EBUSY && !riocm_queue_req(ch->cmdev, ch->rdev,
1420 					      hdr, sizeof(*hdr)))
1421 		return 0;
1422 	kfree(hdr);
1423 
1424 	if (ret)
1425 		riocm_error("ch(%d) send CLOSE failed (ret=%d)", ch->id, ret);
1426 
1427 	return ret;
1428 }
1429 
1430 /*
1431  * riocm_ch_close - closes a channel object with specified ID (by local request)
1432  * @ch: channel to be closed
1433  */
1434 static int riocm_ch_close(struct rio_channel *ch)
1435 {
1436 	unsigned long tmo = msecs_to_jiffies(3000);
1437 	enum rio_cm_state state;
1438 	long wret;
1439 	int ret = 0;
1440 
1441 	riocm_debug(CHOP, "ch_%d by %s(%d)",
1442 		    ch->id, current->comm, task_pid_nr(current));
1443 
1444 	state = riocm_exch(ch, RIO_CM_DESTROYING);
1445 	if (state == RIO_CM_CONNECTED)
1446 		riocm_send_close(ch);
1447 
1448 	complete_all(&ch->comp);
1449 
1450 	riocm_put_channel(ch);
1451 	wret = wait_for_completion_interruptible_timeout(&ch->comp_close, tmo);
1452 
1453 	riocm_debug(WAIT, "wait on %d returns %ld", ch->id, wret);
1454 
1455 	if (wret == 0) {
1456 		/* Timeout on wait occurred */
1457 		riocm_debug(CHOP, "%s(%d) timed out waiting for ch %d",
1458 		       current->comm, task_pid_nr(current), ch->id);
1459 		ret = -ETIMEDOUT;
1460 	} else if (wret == -ERESTARTSYS) {
1461 		/* Wait_for_completion was interrupted by a signal */
1462 		riocm_debug(CHOP, "%s(%d) wait for ch %d was interrupted",
1463 			current->comm, task_pid_nr(current), ch->id);
1464 		ret = -EINTR;
1465 	}
1466 
1467 	if (!ret) {
1468 		riocm_debug(CHOP, "ch_%d resources released", ch->id);
1469 		kfree(ch);
1470 	} else {
1471 		riocm_debug(CHOP, "failed to release ch_%d resources", ch->id);
1472 	}
1473 
1474 	return ret;
1475 }
1476 
1477 /*
1478  * riocm_cdev_open() - Open character device
1479  */
1480 static int riocm_cdev_open(struct inode *inode, struct file *filp)
1481 {
1482 	riocm_debug(INIT, "by %s(%d) filp=%p ",
1483 		    current->comm, task_pid_nr(current), filp);
1484 
1485 	if (list_empty(&cm_dev_list))
1486 		return -ENODEV;
1487 
1488 	return 0;
1489 }
1490 
1491 /*
1492  * riocm_cdev_release() - Release character device
1493  */
1494 static int riocm_cdev_release(struct inode *inode, struct file *filp)
1495 {
1496 	struct rio_channel *ch, *_c;
1497 	unsigned int i;
1498 	LIST_HEAD(list);
1499 
1500 	riocm_debug(EXIT, "by %s(%d) filp=%p",
1501 		    current->comm, task_pid_nr(current), filp);
1502 
1503 	/* Check if there are channels associated with this file descriptor */
1504 	spin_lock_bh(&idr_lock);
1505 	idr_for_each_entry(&ch_idr, ch, i) {
1506 		if (ch && ch->filp == filp) {
1507 			riocm_debug(EXIT, "ch_%d not released by %s(%d)",
1508 				    ch->id, current->comm,
1509 				    task_pid_nr(current));
1510 			idr_remove(&ch_idr, ch->id);
1511 			list_add(&ch->ch_node, &list);
1512 		}
1513 	}
1514 	spin_unlock_bh(&idr_lock);
1515 
1516 	if (!list_empty(&list)) {
1517 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
1518 			list_del(&ch->ch_node);
1519 			riocm_ch_close(ch);
1520 		}
1521 	}
1522 
1523 	return 0;
1524 }
1525 
1526 /*
1527  * cm_ep_get_list_size() - Reports number of endpoints in the network
1528  */
1529 static int cm_ep_get_list_size(void __user *arg)
1530 {
1531 	u32 __user *p = arg;
1532 	u32 mport_id;
1533 	u32 count = 0;
1534 	struct cm_dev *cm;
1535 
1536 	if (get_user(mport_id, p))
1537 		return -EFAULT;
1538 	if (mport_id >= RIO_MAX_MPORTS)
1539 		return -EINVAL;
1540 
1541 	/* Find a matching cm_dev object */
1542 	down_read(&rdev_sem);
1543 	list_for_each_entry(cm, &cm_dev_list, list) {
1544 		if (cm->mport->id == mport_id) {
1545 			count = cm->npeers;
1546 			up_read(&rdev_sem);
1547 			if (copy_to_user(arg, &count, sizeof(u32)))
1548 				return -EFAULT;
1549 			return 0;
1550 		}
1551 	}
1552 	up_read(&rdev_sem);
1553 
1554 	return -ENODEV;
1555 }
1556 
1557 /*
1558  * cm_ep_get_list() - Returns list of attached endpoints
1559  */
1560 static int cm_ep_get_list(void __user *arg)
1561 {
1562 	struct cm_dev *cm;
1563 	struct cm_peer *peer;
1564 	u32 info[2];
1565 	void *buf;
1566 	u32 nent;
1567 	u32 *entry_ptr;
1568 	u32 i = 0;
1569 	int ret = 0;
1570 
1571 	if (copy_from_user(&info, arg, sizeof(info)))
1572 		return -EFAULT;
1573 
1574 	if (info[1] >= RIO_MAX_MPORTS || info[0] > RIOCM_MAX_EP_COUNT)
1575 		return -EINVAL;
1576 
1577 	/* Find a matching cm_dev object */
1578 	down_read(&rdev_sem);
1579 	list_for_each_entry(cm, &cm_dev_list, list)
1580 		if (cm->mport->id == (u8)info[1])
1581 			goto found;
1582 
1583 	up_read(&rdev_sem);
1584 	return -ENODEV;
1585 
1586 found:
1587 	nent = min(info[0], cm->npeers);
1588 	buf = kcalloc(nent + 2, sizeof(u32), GFP_KERNEL);
1589 	if (!buf) {
1590 		up_read(&rdev_sem);
1591 		return -ENOMEM;
1592 	}
1593 
1594 	entry_ptr = (u32 *)((uintptr_t)buf + 2*sizeof(u32));
1595 
1596 	list_for_each_entry(peer, &cm->peers, node) {
1597 		*entry_ptr = (u32)peer->rdev->destid;
1598 		entry_ptr++;
1599 		if (++i == nent)
1600 			break;
1601 	}
1602 	up_read(&rdev_sem);
1603 
1604 	((u32 *)buf)[0] = i; /* report an updated number of entries */
1605 	((u32 *)buf)[1] = info[1]; /* put back an mport ID */
1606 	if (copy_to_user(arg, buf, sizeof(u32) * (info[0] + 2)))
1607 		ret = -EFAULT;
1608 
1609 	kfree(buf);
1610 	return ret;
1611 }
1612 
1613 /*
1614  * cm_mport_get_list() - Returns list of available local mport devices
1615  */
1616 static int cm_mport_get_list(void __user *arg)
1617 {
1618 	int ret = 0;
1619 	u32 entries;
1620 	void *buf;
1621 	struct cm_dev *cm;
1622 	u32 *entry_ptr;
1623 	int count = 0;
1624 
1625 	if (copy_from_user(&entries, arg, sizeof(entries)))
1626 		return -EFAULT;
1627 	if (entries == 0 || entries > RIO_MAX_MPORTS)
1628 		return -EINVAL;
1629 	buf = kcalloc(entries + 1, sizeof(u32), GFP_KERNEL);
1630 	if (!buf)
1631 		return -ENOMEM;
1632 
1633 	/* Scan all registered cm_dev objects */
1634 	entry_ptr = (u32 *)((uintptr_t)buf + sizeof(u32));
1635 	down_read(&rdev_sem);
1636 	list_for_each_entry(cm, &cm_dev_list, list) {
1637 		if (count++ < entries) {
1638 			*entry_ptr = (cm->mport->id << 16) |
1639 				      cm->mport->host_deviceid;
1640 			entry_ptr++;
1641 		}
1642 	}
1643 	up_read(&rdev_sem);
1644 
1645 	*((u32 *)buf) = count; /* report a real number of entries */
1646 	if (copy_to_user(arg, buf, sizeof(u32) * (count + 1)))
1647 		ret = -EFAULT;
1648 
1649 	kfree(buf);
1650 	return ret;
1651 }
1652 
1653 /*
1654  * cm_chan_create() - Create a message exchange channel
1655  */
1656 static int cm_chan_create(struct file *filp, void __user *arg)
1657 {
1658 	u16 __user *p = arg;
1659 	u16 ch_num;
1660 	struct rio_channel *ch;
1661 
1662 	if (get_user(ch_num, p))
1663 		return -EFAULT;
1664 
1665 	riocm_debug(CHOP, "ch_%d requested by %s(%d)",
1666 		    ch_num, current->comm, task_pid_nr(current));
1667 	ch = riocm_ch_create(&ch_num);
1668 	if (IS_ERR(ch))
1669 		return PTR_ERR(ch);
1670 
1671 	ch->filp = filp;
1672 	riocm_debug(CHOP, "ch_%d created by %s(%d)",
1673 		    ch_num, current->comm, task_pid_nr(current));
1674 	return put_user(ch_num, p);
1675 }
1676 
1677 /*
1678  * cm_chan_close() - Close channel
1679  * @filp:	Pointer to file object
1680  * @arg:	Channel to close
1681  */
1682 static int cm_chan_close(struct file *filp, void __user *arg)
1683 {
1684 	u16 __user *p = arg;
1685 	u16 ch_num;
1686 	struct rio_channel *ch;
1687 
1688 	if (get_user(ch_num, p))
1689 		return -EFAULT;
1690 
1691 	riocm_debug(CHOP, "ch_%d by %s(%d)",
1692 		    ch_num, current->comm, task_pid_nr(current));
1693 
1694 	spin_lock_bh(&idr_lock);
1695 	ch = idr_find(&ch_idr, ch_num);
1696 	if (!ch) {
1697 		spin_unlock_bh(&idr_lock);
1698 		return 0;
1699 	}
1700 	if (ch->filp != filp) {
1701 		spin_unlock_bh(&idr_lock);
1702 		return -EINVAL;
1703 	}
1704 	idr_remove(&ch_idr, ch->id);
1705 	spin_unlock_bh(&idr_lock);
1706 
1707 	return riocm_ch_close(ch);
1708 }
1709 
1710 /*
1711  * cm_chan_bind() - Bind channel
1712  * @arg:	Channel number
1713  */
1714 static int cm_chan_bind(void __user *arg)
1715 {
1716 	struct rio_cm_channel chan;
1717 
1718 	if (copy_from_user(&chan, arg, sizeof(chan)))
1719 		return -EFAULT;
1720 	if (chan.mport_id >= RIO_MAX_MPORTS)
1721 		return -EINVAL;
1722 
1723 	return riocm_ch_bind(chan.id, chan.mport_id, NULL);
1724 }
1725 
1726 /*
1727  * cm_chan_listen() - Listen on channel
1728  * @arg:	Channel number
1729  */
1730 static int cm_chan_listen(void __user *arg)
1731 {
1732 	u16 __user *p = arg;
1733 	u16 ch_num;
1734 
1735 	if (get_user(ch_num, p))
1736 		return -EFAULT;
1737 
1738 	return riocm_ch_listen(ch_num);
1739 }
1740 
1741 /*
1742  * cm_chan_accept() - Accept incoming connection
1743  * @filp:	Pointer to file object
1744  * @arg:	Channel number
1745  */
1746 static int cm_chan_accept(struct file *filp, void __user *arg)
1747 {
1748 	struct rio_cm_accept param;
1749 	long accept_to;
1750 	struct rio_channel *ch;
1751 
1752 	if (copy_from_user(&param, arg, sizeof(param)))
1753 		return -EFAULT;
1754 
1755 	riocm_debug(CHOP, "on ch_%d by %s(%d)",
1756 		    param.ch_num, current->comm, task_pid_nr(current));
1757 
1758 	accept_to = param.wait_to ?
1759 			msecs_to_jiffies(param.wait_to) : 0;
1760 
1761 	ch = riocm_ch_accept(param.ch_num, &param.ch_num, accept_to);
1762 	if (IS_ERR(ch))
1763 		return PTR_ERR(ch);
1764 	ch->filp = filp;
1765 
1766 	riocm_debug(CHOP, "new ch_%d for %s(%d)",
1767 		    ch->id, current->comm, task_pid_nr(current));
1768 
1769 	if (copy_to_user(arg, &param, sizeof(param)))
1770 		return -EFAULT;
1771 	return 0;
1772 }
1773 
1774 /*
1775  * cm_chan_connect() - Connect on channel
1776  * @arg:	Channel information
1777  */
1778 static int cm_chan_connect(void __user *arg)
1779 {
1780 	struct rio_cm_channel chan;
1781 	struct cm_dev *cm;
1782 	struct cm_peer *peer;
1783 	int ret = -ENODEV;
1784 
1785 	if (copy_from_user(&chan, arg, sizeof(chan)))
1786 		return -EFAULT;
1787 	if (chan.mport_id >= RIO_MAX_MPORTS)
1788 		return -EINVAL;
1789 
1790 	down_read(&rdev_sem);
1791 
1792 	/* Find matching cm_dev object */
1793 	list_for_each_entry(cm, &cm_dev_list, list) {
1794 		if (cm->mport->id == chan.mport_id) {
1795 			ret = 0;
1796 			break;
1797 		}
1798 	}
1799 
1800 	if (ret)
1801 		goto err_out;
1802 
1803 	if (chan.remote_destid >= RIO_ANY_DESTID(cm->mport->sys_size)) {
1804 		ret = -EINVAL;
1805 		goto err_out;
1806 	}
1807 
1808 	/* Find corresponding RapidIO endpoint device object */
1809 	ret = -ENODEV;
1810 
1811 	list_for_each_entry(peer, &cm->peers, node) {
1812 		if (peer->rdev->destid == chan.remote_destid) {
1813 			ret = 0;
1814 			break;
1815 		}
1816 	}
1817 
1818 	if (ret)
1819 		goto err_out;
1820 
1821 	up_read(&rdev_sem);
1822 
1823 	return riocm_ch_connect(chan.id, cm, peer, chan.remote_channel);
1824 err_out:
1825 	up_read(&rdev_sem);
1826 	return ret;
1827 }
1828 
1829 /*
1830  * cm_chan_msg_send() - Send a message through channel
1831  * @arg:	Outbound message information
1832  */
1833 static int cm_chan_msg_send(void __user *arg)
1834 {
1835 	struct rio_cm_msg msg;
1836 	void *buf;
1837 	int ret;
1838 
1839 	if (copy_from_user(&msg, arg, sizeof(msg)))
1840 		return -EFAULT;
1841 	if (msg.size > RIO_MAX_MSG_SIZE)
1842 		return -EINVAL;
1843 
1844 	buf = memdup_user((void __user *)(uintptr_t)msg.msg, msg.size);
1845 	if (IS_ERR(buf))
1846 		return PTR_ERR(buf);
1847 
1848 	ret = riocm_ch_send(msg.ch_num, buf, msg.size);
1849 
1850 	kfree(buf);
1851 	return ret;
1852 }
1853 
1854 /*
1855  * cm_chan_msg_rcv() - Receive a message through channel
1856  * @arg:	Inbound message information
1857  */
1858 static int cm_chan_msg_rcv(void __user *arg)
1859 {
1860 	struct rio_cm_msg msg;
1861 	struct rio_channel *ch;
1862 	void *buf;
1863 	long rxto;
1864 	int ret = 0, msg_size;
1865 
1866 	if (copy_from_user(&msg, arg, sizeof(msg)))
1867 		return -EFAULT;
1868 
1869 	if (msg.ch_num == 0 || msg.size == 0)
1870 		return -EINVAL;
1871 
1872 	ch = riocm_get_channel(msg.ch_num);
1873 	if (!ch)
1874 		return -ENODEV;
1875 
1876 	rxto = msg.rxto ? msecs_to_jiffies(msg.rxto) : MAX_SCHEDULE_TIMEOUT;
1877 
1878 	ret = riocm_ch_receive(ch, &buf, rxto);
1879 	if (ret)
1880 		goto out;
1881 
1882 	msg_size = min(msg.size, (u16)(RIO_MAX_MSG_SIZE));
1883 
1884 	if (copy_to_user((void __user *)(uintptr_t)msg.msg, buf, msg_size))
1885 		ret = -EFAULT;
1886 
1887 	riocm_ch_free_rxbuf(ch, buf);
1888 out:
1889 	riocm_put_channel(ch);
1890 	return ret;
1891 }
1892 
1893 /*
1894  * riocm_cdev_ioctl() - IOCTL requests handler
1895  */
1896 static long
1897 riocm_cdev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1898 {
1899 	switch (cmd) {
1900 	case RIO_CM_EP_GET_LIST_SIZE:
1901 		return cm_ep_get_list_size((void __user *)arg);
1902 	case RIO_CM_EP_GET_LIST:
1903 		return cm_ep_get_list((void __user *)arg);
1904 	case RIO_CM_CHAN_CREATE:
1905 		return cm_chan_create(filp, (void __user *)arg);
1906 	case RIO_CM_CHAN_CLOSE:
1907 		return cm_chan_close(filp, (void __user *)arg);
1908 	case RIO_CM_CHAN_BIND:
1909 		return cm_chan_bind((void __user *)arg);
1910 	case RIO_CM_CHAN_LISTEN:
1911 		return cm_chan_listen((void __user *)arg);
1912 	case RIO_CM_CHAN_ACCEPT:
1913 		return cm_chan_accept(filp, (void __user *)arg);
1914 	case RIO_CM_CHAN_CONNECT:
1915 		return cm_chan_connect((void __user *)arg);
1916 	case RIO_CM_CHAN_SEND:
1917 		return cm_chan_msg_send((void __user *)arg);
1918 	case RIO_CM_CHAN_RECEIVE:
1919 		return cm_chan_msg_rcv((void __user *)arg);
1920 	case RIO_CM_MPORT_GET_LIST:
1921 		return cm_mport_get_list((void __user *)arg);
1922 	default:
1923 		break;
1924 	}
1925 
1926 	return -EINVAL;
1927 }
1928 
1929 static const struct file_operations riocm_cdev_fops = {
1930 	.owner		= THIS_MODULE,
1931 	.open		= riocm_cdev_open,
1932 	.release	= riocm_cdev_release,
1933 	.unlocked_ioctl = riocm_cdev_ioctl,
1934 };
1935 
1936 /*
1937  * riocm_add_dev - add new remote RapidIO device into channel management core
1938  * @dev: device object associated with RapidIO device
1939  * @sif: subsystem interface
1940  *
1941  * Adds the specified RapidIO device (if applicable) into peers list of
1942  * the corresponding channel management device (cm_dev).
1943  */
1944 static int riocm_add_dev(struct device *dev, struct subsys_interface *sif)
1945 {
1946 	struct cm_peer *peer;
1947 	struct rio_dev *rdev = to_rio_dev(dev);
1948 	struct cm_dev *cm;
1949 
1950 	/* Check if the remote device has capabilities required to support CM */
1951 	if (!dev_cm_capable(rdev))
1952 		return 0;
1953 
1954 	riocm_debug(RDEV, "(%s)", rio_name(rdev));
1955 
1956 	peer = kmalloc(sizeof(*peer), GFP_KERNEL);
1957 	if (!peer)
1958 		return -ENOMEM;
1959 
1960 	/* Find a corresponding cm_dev object */
1961 	down_write(&rdev_sem);
1962 	list_for_each_entry(cm, &cm_dev_list, list) {
1963 		if (cm->mport == rdev->net->hport)
1964 			goto found;
1965 	}
1966 
1967 	up_write(&rdev_sem);
1968 	kfree(peer);
1969 	return -ENODEV;
1970 
1971 found:
1972 	peer->rdev = rdev;
1973 	list_add_tail(&peer->node, &cm->peers);
1974 	cm->npeers++;
1975 
1976 	up_write(&rdev_sem);
1977 	return 0;
1978 }
1979 
1980 /*
1981  * riocm_remove_dev - remove remote RapidIO device from channel management core
1982  * @dev: device object associated with RapidIO device
1983  * @sif: subsystem interface
1984  *
1985  * Removes the specified RapidIO device (if applicable) from peers list of
1986  * the corresponding channel management device (cm_dev).
1987  */
1988 static void riocm_remove_dev(struct device *dev, struct subsys_interface *sif)
1989 {
1990 	struct rio_dev *rdev = to_rio_dev(dev);
1991 	struct cm_dev *cm;
1992 	struct cm_peer *peer;
1993 	struct rio_channel *ch, *_c;
1994 	unsigned int i;
1995 	bool found = false;
1996 	LIST_HEAD(list);
1997 
1998 	/* Check if the remote device has capabilities required to support CM */
1999 	if (!dev_cm_capable(rdev))
2000 		return;
2001 
2002 	riocm_debug(RDEV, "(%s)", rio_name(rdev));
2003 
2004 	/* Find matching cm_dev object */
2005 	down_write(&rdev_sem);
2006 	list_for_each_entry(cm, &cm_dev_list, list) {
2007 		if (cm->mport == rdev->net->hport) {
2008 			found = true;
2009 			break;
2010 		}
2011 	}
2012 
2013 	if (!found) {
2014 		up_write(&rdev_sem);
2015 		return;
2016 	}
2017 
2018 	/* Remove remote device from the list of peers */
2019 	found = false;
2020 	list_for_each_entry(peer, &cm->peers, node) {
2021 		if (peer->rdev == rdev) {
2022 			riocm_debug(RDEV, "removing peer %s", rio_name(rdev));
2023 			found = true;
2024 			list_del(&peer->node);
2025 			cm->npeers--;
2026 			kfree(peer);
2027 			break;
2028 		}
2029 	}
2030 
2031 	up_write(&rdev_sem);
2032 
2033 	if (!found)
2034 		return;
2035 
2036 	/*
2037 	 * Release channels associated with this peer
2038 	 */
2039 
2040 	spin_lock_bh(&idr_lock);
2041 	idr_for_each_entry(&ch_idr, ch, i) {
2042 		if (ch && ch->rdev == rdev) {
2043 			if (atomic_read(&rdev->state) != RIO_DEVICE_SHUTDOWN)
2044 				riocm_exch(ch, RIO_CM_DISCONNECT);
2045 			idr_remove(&ch_idr, ch->id);
2046 			list_add(&ch->ch_node, &list);
2047 		}
2048 	}
2049 	spin_unlock_bh(&idr_lock);
2050 
2051 	if (!list_empty(&list)) {
2052 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
2053 			list_del(&ch->ch_node);
2054 			riocm_ch_close(ch);
2055 		}
2056 	}
2057 }
2058 
2059 /*
2060  * riocm_cdev_add() - Create rio_cm char device
2061  * @devno: device number assigned to device (MAJ + MIN)
2062  */
2063 static int riocm_cdev_add(dev_t devno)
2064 {
2065 	int ret;
2066 
2067 	cdev_init(&riocm_cdev.cdev, &riocm_cdev_fops);
2068 	riocm_cdev.cdev.owner = THIS_MODULE;
2069 	ret = cdev_add(&riocm_cdev.cdev, devno, 1);
2070 	if (ret < 0) {
2071 		riocm_error("Cannot register a device with error %d", ret);
2072 		return ret;
2073 	}
2074 
2075 	riocm_cdev.dev = device_create(dev_class, NULL, devno, NULL, DEV_NAME);
2076 	if (IS_ERR(riocm_cdev.dev)) {
2077 		cdev_del(&riocm_cdev.cdev);
2078 		return PTR_ERR(riocm_cdev.dev);
2079 	}
2080 
2081 	riocm_debug(MPORT, "Added %s cdev(%d:%d)",
2082 		    DEV_NAME, MAJOR(devno), MINOR(devno));
2083 
2084 	return 0;
2085 }
2086 
2087 /*
2088  * riocm_add_mport - add new local mport device into channel management core
2089  * @dev: device object associated with mport
2090  *
2091  * When a new mport device is added, CM immediately reserves inbound and
2092  * outbound RapidIO mailboxes that will be used.
2093  */
2094 static int riocm_add_mport(struct device *dev)
2095 {
2096 	int rc;
2097 	int i;
2098 	struct cm_dev *cm;
2099 	struct rio_mport *mport = to_rio_mport(dev);
2100 
2101 	riocm_debug(MPORT, "add mport %s", mport->name);
2102 
2103 	cm = kzalloc(sizeof(*cm), GFP_KERNEL);
2104 	if (!cm)
2105 		return -ENOMEM;
2106 
2107 	cm->mport = mport;
2108 
2109 	rc = rio_request_outb_mbox(mport, cm, cmbox,
2110 				   RIOCM_TX_RING_SIZE, riocm_outb_msg_event);
2111 	if (rc) {
2112 		riocm_error("failed to allocate OBMBOX_%d on %s",
2113 			    cmbox, mport->name);
2114 		kfree(cm);
2115 		return -ENODEV;
2116 	}
2117 
2118 	rc = rio_request_inb_mbox(mport, cm, cmbox,
2119 				  RIOCM_RX_RING_SIZE, riocm_inb_msg_event);
2120 	if (rc) {
2121 		riocm_error("failed to allocate IBMBOX_%d on %s",
2122 			    cmbox, mport->name);
2123 		rio_release_outb_mbox(mport, cmbox);
2124 		kfree(cm);
2125 		return -ENODEV;
2126 	}
2127 
2128 	cm->rx_wq = create_workqueue(DRV_NAME "/rxq");
2129 	if (!cm->rx_wq) {
2130 		rio_release_inb_mbox(mport, cmbox);
2131 		rio_release_outb_mbox(mport, cmbox);
2132 		kfree(cm);
2133 		return -ENOMEM;
2134 	}
2135 
2136 	/*
2137 	 * Allocate and register inbound messaging buffers to be ready
2138 	 * to receive channel and system management requests
2139 	 */
2140 	for (i = 0; i < RIOCM_RX_RING_SIZE; i++)
2141 		cm->rx_buf[i] = NULL;
2142 
2143 	cm->rx_slots = RIOCM_RX_RING_SIZE;
2144 	mutex_init(&cm->rx_lock);
2145 	riocm_rx_fill(cm, RIOCM_RX_RING_SIZE);
2146 	INIT_WORK(&cm->rx_work, rio_ibmsg_handler);
2147 
2148 	cm->tx_slot = 0;
2149 	cm->tx_cnt = 0;
2150 	cm->tx_ack_slot = 0;
2151 	spin_lock_init(&cm->tx_lock);
2152 
2153 	INIT_LIST_HEAD(&cm->peers);
2154 	cm->npeers = 0;
2155 	INIT_LIST_HEAD(&cm->tx_reqs);
2156 
2157 	down_write(&rdev_sem);
2158 	list_add_tail(&cm->list, &cm_dev_list);
2159 	up_write(&rdev_sem);
2160 
2161 	return 0;
2162 }
2163 
2164 /*
2165  * riocm_remove_mport - remove local mport device from channel management core
2166  * @dev: device object associated with mport
2167  *
2168  * Removes a local mport device from the list of registered devices that provide
2169  * channel management services. Returns an error if the specified mport is not
2170  * registered with the CM core.
2171  */
2172 static void riocm_remove_mport(struct device *dev)
2173 {
2174 	struct rio_mport *mport = to_rio_mport(dev);
2175 	struct cm_dev *cm;
2176 	struct cm_peer *peer, *temp;
2177 	struct rio_channel *ch, *_c;
2178 	unsigned int i;
2179 	bool found = false;
2180 	LIST_HEAD(list);
2181 
2182 	riocm_debug(MPORT, "%s", mport->name);
2183 
2184 	/* Find a matching cm_dev object */
2185 	down_write(&rdev_sem);
2186 	list_for_each_entry(cm, &cm_dev_list, list) {
2187 		if (cm->mport == mport) {
2188 			list_del(&cm->list);
2189 			found = true;
2190 			break;
2191 		}
2192 	}
2193 	up_write(&rdev_sem);
2194 	if (!found)
2195 		return;
2196 
2197 	flush_workqueue(cm->rx_wq);
2198 	destroy_workqueue(cm->rx_wq);
2199 
2200 	/* Release channels bound to this mport */
2201 	spin_lock_bh(&idr_lock);
2202 	idr_for_each_entry(&ch_idr, ch, i) {
2203 		if (ch->cmdev == cm) {
2204 			riocm_debug(RDEV, "%s drop ch_%d",
2205 				    mport->name, ch->id);
2206 			idr_remove(&ch_idr, ch->id);
2207 			list_add(&ch->ch_node, &list);
2208 		}
2209 	}
2210 	spin_unlock_bh(&idr_lock);
2211 
2212 	if (!list_empty(&list)) {
2213 		list_for_each_entry_safe(ch, _c, &list, ch_node) {
2214 			list_del(&ch->ch_node);
2215 			riocm_ch_close(ch);
2216 		}
2217 	}
2218 
2219 	rio_release_inb_mbox(mport, cmbox);
2220 	rio_release_outb_mbox(mport, cmbox);
2221 
2222 	/* Remove and free peer entries */
2223 	if (!list_empty(&cm->peers))
2224 		riocm_debug(RDEV, "ATTN: peer list not empty");
2225 	list_for_each_entry_safe(peer, temp, &cm->peers, node) {
2226 		riocm_debug(RDEV, "removing peer %s", rio_name(peer->rdev));
2227 		list_del(&peer->node);
2228 		kfree(peer);
2229 	}
2230 
2231 	riocm_rx_free(cm);
2232 	kfree(cm);
2233 	riocm_debug(MPORT, "%s done", mport->name);
2234 }
2235 
2236 static int rio_cm_shutdown(struct notifier_block *nb, unsigned long code,
2237 	void *unused)
2238 {
2239 	struct rio_channel *ch;
2240 	unsigned int i;
2241 	LIST_HEAD(list);
2242 
2243 	riocm_debug(EXIT, ".");
2244 
2245 	/*
2246 	 * If there are any channels left in connected state send
2247 	 * close notification to the connection partner.
2248 	 * First build a list of channels that require a closing
2249 	 * notification because function riocm_send_close() should
2250 	 * be called outside of spinlock protected code.
2251 	 */
2252 	spin_lock_bh(&idr_lock);
2253 	idr_for_each_entry(&ch_idr, ch, i) {
2254 		if (ch->state == RIO_CM_CONNECTED) {
2255 			riocm_debug(EXIT, "close ch %d", ch->id);
2256 			idr_remove(&ch_idr, ch->id);
2257 			list_add(&ch->ch_node, &list);
2258 		}
2259 	}
2260 	spin_unlock_bh(&idr_lock);
2261 
2262 	list_for_each_entry(ch, &list, ch_node)
2263 		riocm_send_close(ch);
2264 
2265 	return NOTIFY_DONE;
2266 }
2267 
2268 /*
2269  * riocm_interface handles addition/removal of remote RapidIO devices
2270  */
2271 static struct subsys_interface riocm_interface = {
2272 	.name		= "rio_cm",
2273 	.subsys		= &rio_bus_type,
2274 	.add_dev	= riocm_add_dev,
2275 	.remove_dev	= riocm_remove_dev,
2276 };
2277 
2278 /*
2279  * rio_mport_interface handles addition/removal local mport devices
2280  */
2281 static struct class_interface rio_mport_interface __refdata = {
2282 	.class = &rio_mport_class,
2283 	.add_dev = riocm_add_mport,
2284 	.remove_dev = riocm_remove_mport,
2285 };
2286 
2287 static struct notifier_block rio_cm_notifier = {
2288 	.notifier_call = rio_cm_shutdown,
2289 };
2290 
2291 static int __init riocm_init(void)
2292 {
2293 	int ret;
2294 
2295 	/* Create device class needed by udev */
2296 	dev_class = class_create(DRV_NAME);
2297 	if (IS_ERR(dev_class)) {
2298 		riocm_error("Cannot create " DRV_NAME " class");
2299 		return PTR_ERR(dev_class);
2300 	}
2301 
2302 	ret = alloc_chrdev_region(&dev_number, 0, 1, DRV_NAME);
2303 	if (ret) {
2304 		class_destroy(dev_class);
2305 		return ret;
2306 	}
2307 
2308 	dev_major = MAJOR(dev_number);
2309 	dev_minor_base = MINOR(dev_number);
2310 	riocm_debug(INIT, "Registered class with %d major", dev_major);
2311 
2312 	/*
2313 	 * Register as rapidio_port class interface to get notifications about
2314 	 * mport additions and removals.
2315 	 */
2316 	ret = class_interface_register(&rio_mport_interface);
2317 	if (ret) {
2318 		riocm_error("class_interface_register error: %d", ret);
2319 		goto err_reg;
2320 	}
2321 
2322 	/*
2323 	 * Register as RapidIO bus interface to get notifications about
2324 	 * addition/removal of remote RapidIO devices.
2325 	 */
2326 	ret = subsys_interface_register(&riocm_interface);
2327 	if (ret) {
2328 		riocm_error("subsys_interface_register error: %d", ret);
2329 		goto err_cl;
2330 	}
2331 
2332 	ret = register_reboot_notifier(&rio_cm_notifier);
2333 	if (ret) {
2334 		riocm_error("failed to register reboot notifier (err=%d)", ret);
2335 		goto err_sif;
2336 	}
2337 
2338 	ret = riocm_cdev_add(dev_number);
2339 	if (ret) {
2340 		unregister_reboot_notifier(&rio_cm_notifier);
2341 		ret = -ENODEV;
2342 		goto err_sif;
2343 	}
2344 
2345 	return 0;
2346 err_sif:
2347 	subsys_interface_unregister(&riocm_interface);
2348 err_cl:
2349 	class_interface_unregister(&rio_mport_interface);
2350 err_reg:
2351 	unregister_chrdev_region(dev_number, 1);
2352 	class_destroy(dev_class);
2353 	return ret;
2354 }
2355 
2356 static void __exit riocm_exit(void)
2357 {
2358 	riocm_debug(EXIT, "enter");
2359 	unregister_reboot_notifier(&rio_cm_notifier);
2360 	subsys_interface_unregister(&riocm_interface);
2361 	class_interface_unregister(&rio_mport_interface);
2362 	idr_destroy(&ch_idr);
2363 
2364 	device_unregister(riocm_cdev.dev);
2365 	cdev_del(&(riocm_cdev.cdev));
2366 
2367 	class_destroy(dev_class);
2368 	unregister_chrdev_region(dev_number, 1);
2369 }
2370 
2371 late_initcall(riocm_init);
2372 module_exit(riocm_exit);
2373