aboutsummaryrefslogtreecommitdiff
path: root/drivers/misc/sgi-xp/xp_main.c
blob: c5cec606377d18eddd4ab3df4069548f011c015c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
 */

/*
 * Cross Partition (XP) base.
 *
 *	XP provides a base from which its users can interact
 *	with XPC, yet not be dependent on XPC.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include "xp.h"

/* define the XP debug device structures to be used with dev_dbg() et al */

struct device_driver xp_dbg_name = {
	.name = "xp"
};

struct device xp_dbg_subname = {
	.bus_id = {0},		/* set to "" */
	.driver = &xp_dbg_name
};

struct device *xp = &xp_dbg_subname;

/* max #of partitions possible */
short xp_max_npartitions;
EXPORT_SYMBOL_GPL(xp_max_npartitions);

/*
 * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
 * users of XPC.
 */
struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
EXPORT_SYMBOL_GPL(xpc_registrations);

/*
 * Initialize the XPC interface to indicate that XPC isn't loaded.
 */
static enum xp_retval
xpc_notloaded(void)
{
	return xpNotLoaded;
}

struct xpc_interface xpc_interface = {
	(void (*)(int))xpc_notloaded,
	(void (*)(int))xpc_notloaded,
	(enum xp_retval(*)(short, int, u32, void **))xpc_notloaded,
	(enum xp_retval(*)(short, int, void *))xpc_notloaded,
	(enum xp_retval(*)(short, int, void *, xpc_notify_func, void *))
	    xpc_notloaded,
	(void (*)(short, int, void *))xpc_notloaded,
	(enum xp_retval(*)(short, void *))xpc_notloaded
};
EXPORT_SYMBOL_GPL(xpc_interface);

/*
 * XPC calls this when it (the XPC module) has been loaded.
 */
void
xpc_set_interface(void (*connect) (int),
		  void (*disconnect) (int),
		  enum xp_retval (*allocate) (short, int, u32, void **),
		  enum xp_retval (*send) (short, int, void *),
		  enum xp_retval (*send_notify) (short, int, void *,
						  xpc_notify_func, void *),
		  void (*received) (short, int, void *),
		  enum xp_retval (*partid_to_nasids) (short, void *))
{
	xpc_interface.connect = connect;
	xpc_interface.disconnect = disconnect;
	xpc_interface.allocate = allocate;
	xpc_interface.send = send;
	xpc_interface.send_notify = send_notify;
	xpc_interface.received = received;
	xpc_interface.partid_to_nasids = partid_to_nasids;
}
EXPORT_SYMBOL_GPL(xpc_set_interface);

/*
 * XPC calls this when it (the XPC module) is being unloaded.
 */
void
xpc_clear_interface(void)
{
	xpc_interface.connect = (void (*)(int))xpc_notloaded;
	xpc_interface.disconnect = (void (*)(int))xpc_notloaded;
	xpc_interface.allocate = (enum xp_retval(*)(short, int, u32,
						     void **))xpc_notloaded;
	xpc_interface.send = (enum xp_retval(*)(short, int, void *))
	    xpc_notloaded;
	xpc_interface.send_notify = (enum xp_retval(*)(short, int, void *,
							xpc_notify_func,
							void *))xpc_notloaded;
	xpc_interface.received = (void (*)(short, int, void *))
	    xpc_notloaded;
	xpc_interface.partid_to_nasids = (enum xp_retval(*)(short, void *))
	    xpc_notloaded;
}
EXPORT_SYMBOL_GPL(xpc_clear_interface);

/*
 * Register for automatic establishment of a channel connection whenever
 * a partition comes up.
 *
 * Arguments:
 *
 *	ch_number - channel # to register for connection.
 *	func - function to call for asynchronous notification of channel
 *	       state changes (i.e., connection, disconnection, error) and
 *	       the arrival of incoming messages.
 *      key - pointer to optional user-defined value that gets passed back
 *	      to the user on any callouts made to func.
 *	payload_size - size in bytes of the XPC message's payload area which
 *		       contains a user-defined message. The user should make
 *		       this large enough to hold their largest message.
 *	nentries - max #of XPC message entries a message queue can contain.
 *		   The actual number, which is determined when a connection
 * 		   is established and may be less then requested, will be
 *		   passed to the user via the xpConnected callout.
 *	assigned_limit - max number of kthreads allowed to be processing
 * 			 messages (per connection) at any given instant.
 *	idle_limit - max number of kthreads allowed to be idle at any given
 * 		     instant.
 */
enum xp_retval
xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
	    u16 nentries, u32 assigned_limit, u32 idle_limit)
{
	struct xpc_registration *registration;

	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
	DBUG_ON(payload_size == 0 || nentries == 0);
	DBUG_ON(func == NULL);
	DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);

	registration = &xpc_registrations[ch_number];

	if (mutex_lock_interruptible(&registration->mutex) != 0)
		return xpInterrupted;

	/* if XPC_CHANNEL_REGISTERED(ch_number) */
	if (registration->func != NULL) {
		mutex_unlock(&registration->mutex);
		return xpAlreadyRegistered;
	}

	/* register the channel for connection */
	registration->msg_size = XPC_MSG_SIZE(payload_size);
	registration->nentries = nentries;
	registration->assigned_limit = assigned_limit;
	registration->idle_limit = idle_limit;
	registration->key = key;
	registration->func = func;

	mutex_unlock(&registration->mutex);

	xpc_interface.connect(ch_number);

	return xpSuccess;
}
EXPORT_SYMBOL_GPL(xpc_connect);

/*
 * Remove the registration for automatic connection of the specified channel
 * when a partition comes up.
 *
 * Before returning this xpc_disconnect() will wait for all connections on the
 * specified channel have been closed/torndown. So the caller can be assured
 * that they will not be receiving any more callouts from XPC to their
 * function registered via xpc_connect().
 *
 * Arguments:
 *
 *	ch_number - channel # to unregister.
 */
void
xpc_disconnect(int ch_number)
{
	struct xpc_registration *registration;

	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);

	registration = &xpc_registrations[ch_number];

	/*
	 * We've decided not to make this a down_interruptible(), since we
	 * figured XPC's users will just turn around and call xpc_disconnect()
	 * again anyways, so we might as well wait, if need be.
	 */
	mutex_lock(&registration->mutex);

	/* if !XPC_CHANNEL_REGISTERED(ch_number) */
	if (registration->func == NULL) {
		mutex_unlock(&registration->mutex);
		return;
	}

	/* remove the connection registration for the specified channel */
	registration->func = NULL;
	registration->key = NULL;
	registration->nentries = 0;
	registration->msg_size = 0;
	registration->assigned_limit = 0;
	registration->idle_limit = 0;

	xpc_interface.disconnect(ch_number);

	mutex_unlock(&registration->mutex);

	return;
}
EXPORT_SYMBOL_GPL(xpc_disconnect);

int __init
xp_init(void)
{
	enum xp_retval ret;
	int ch_number;

	if (is_shub())
		ret = xp_init_sn2();
	else if (is_uv())
		ret = xp_init_uv();
	else
		ret = xpUnsupported;

	if (ret != xpSuccess)
		return -ENODEV;

	/* initialize the connection registration mutex */
	for (ch_number = 0; ch_number < XPC_MAX_NCHANNELS; ch_number++)
		mutex_init(&xpc_registrations[ch_number].mutex);

	return 0;
}

module_init(xp_init);

void __exit
xp_exit(void)
{
	if (is_shub())
		xp_exit_sn2();
	else if (is_uv())
		xp_exit_uv();
}

module_exit(xp_exit);

MODULE_AUTHOR("Silicon Graphics, Inc.");
MODULE_DESCRIPTION("Cross Partition (XP) base");
MODULE_LICENSE("GPL");