1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
7 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
8 */
9
10/*
11 * Cross Partition (XP) base.
12 *
13 *	XP provides a base from which its users can interact
14 *	with XPC, yet not be dependent on XPC.
15 *
16 */
17
18#include <linux/module.h>
19#include <linux/device.h>
20#include "xp.h"
21
22/* define the XP debug device structures to be used with dev_dbg() et al */
23
24static struct device_driver xp_dbg_name = {
25	.name = "xp"
26};
27
28static struct device xp_dbg_subname = {
29	.init_name = "",		/* set to "" */
30	.driver = &xp_dbg_name
31};
32
33struct device *xp = &xp_dbg_subname;
34
35/* max #of partitions possible */
36short xp_max_npartitions;
37EXPORT_SYMBOL_GPL(xp_max_npartitions);
38
39short xp_partition_id;
40EXPORT_SYMBOL_GPL(xp_partition_id);
41
42u8 xp_region_size;
43EXPORT_SYMBOL_GPL(xp_region_size);
44
45unsigned long (*xp_pa) (void *addr);
46EXPORT_SYMBOL_GPL(xp_pa);
47
48unsigned long (*xp_socket_pa) (unsigned long gpa);
49EXPORT_SYMBOL_GPL(xp_socket_pa);
50
51enum xp_retval (*xp_remote_memcpy) (unsigned long dst_gpa,
52				    const unsigned long src_gpa, size_t len);
53EXPORT_SYMBOL_GPL(xp_remote_memcpy);
54
55int (*xp_cpu_to_nasid) (int cpuid);
56EXPORT_SYMBOL_GPL(xp_cpu_to_nasid);
57
58enum xp_retval (*xp_expand_memprotect) (unsigned long phys_addr,
59					unsigned long size);
60EXPORT_SYMBOL_GPL(xp_expand_memprotect);
61enum xp_retval (*xp_restrict_memprotect) (unsigned long phys_addr,
62					  unsigned long size);
63EXPORT_SYMBOL_GPL(xp_restrict_memprotect);
64
65/*
66 * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
67 * users of XPC.
68 */
69struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
70EXPORT_SYMBOL_GPL(xpc_registrations);
71
72/*
73 * Initialize the XPC interface to NULL to indicate that XPC isn't loaded.
74 */
75struct xpc_interface xpc_interface = { };
76EXPORT_SYMBOL_GPL(xpc_interface);
77
78/*
79 * XPC calls this when it (the XPC module) has been loaded.
80 */
81void
82xpc_set_interface(void (*connect) (int),
83		  void (*disconnect) (int),
84		  enum xp_retval (*send) (short, int, u32, void *, u16),
85		  enum xp_retval (*send_notify) (short, int, u32, void *, u16,
86						  xpc_notify_func, void *),
87		  void (*received) (short, int, void *),
88		  enum xp_retval (*partid_to_nasids) (short, void *))
89{
90	xpc_interface.connect = connect;
91	xpc_interface.disconnect = disconnect;
92	xpc_interface.send = send;
93	xpc_interface.send_notify = send_notify;
94	xpc_interface.received = received;
95	xpc_interface.partid_to_nasids = partid_to_nasids;
96}
97EXPORT_SYMBOL_GPL(xpc_set_interface);
98
99/*
100 * XPC calls this when it (the XPC module) is being unloaded.
101 */
102void
103xpc_clear_interface(void)
104{
105	memset(&xpc_interface, 0, sizeof(xpc_interface));
106}
107EXPORT_SYMBOL_GPL(xpc_clear_interface);
108
109/*
110 * Register for automatic establishment of a channel connection whenever
111 * a partition comes up.
112 *
113 * Arguments:
114 *
115 *	ch_number - channel # to register for connection.
116 *	func - function to call for asynchronous notification of channel
117 *	       state changes (i.e., connection, disconnection, error) and
118 *	       the arrival of incoming messages.
119 *      key - pointer to optional user-defined value that gets passed back
120 *	      to the user on any callouts made to func.
121 *	payload_size - size in bytes of the XPC message's payload area which
122 *		       contains a user-defined message. The user should make
123 *		       this large enough to hold their largest message.
124 *	nentries - max #of XPC message entries a message queue can contain.
125 *		   The actual number, which is determined when a connection
126 * 		   is established and may be less then requested, will be
127 *		   passed to the user via the xpConnected callout.
128 *	assigned_limit - max number of kthreads allowed to be processing
129 * 			 messages (per connection) at any given instant.
130 *	idle_limit - max number of kthreads allowed to be idle at any given
131 * 		     instant.
132 */
133enum xp_retval
134xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
135	    u16 nentries, u32 assigned_limit, u32 idle_limit)
136{
137	struct xpc_registration *registration;
138
139	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
140	DBUG_ON(payload_size == 0 || nentries == 0);
141	DBUG_ON(func == NULL);
142	DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
143
144	if (XPC_MSG_SIZE(payload_size) > XPC_MSG_MAX_SIZE)
145		return xpPayloadTooBig;
146
147	registration = &xpc_registrations[ch_number];
148
149	if (mutex_lock_interruptible(&registration->mutex) != 0)
150		return xpInterrupted;
151
152	/* if XPC_CHANNEL_REGISTERED(ch_number) */
153	if (registration->func != NULL) {
154		mutex_unlock(&registration->mutex);
155		return xpAlreadyRegistered;
156	}
157
158	/* register the channel for connection */
159	registration->entry_size = XPC_MSG_SIZE(payload_size);
160	registration->nentries = nentries;
161	registration->assigned_limit = assigned_limit;
162	registration->idle_limit = idle_limit;
163	registration->key = key;
164	registration->func = func;
165
166	mutex_unlock(&registration->mutex);
167
168	if (xpc_interface.connect)
169		xpc_interface.connect(ch_number);
170
171	return xpSuccess;
172}
173EXPORT_SYMBOL_GPL(xpc_connect);
174
175/*
176 * Remove the registration for automatic connection of the specified channel
177 * when a partition comes up.
178 *
179 * Before returning this xpc_disconnect() will wait for all connections on the
180 * specified channel have been closed/torndown. So the caller can be assured
181 * that they will not be receiving any more callouts from XPC to their
182 * function registered via xpc_connect().
183 *
184 * Arguments:
185 *
186 *	ch_number - channel # to unregister.
187 */
188void
189xpc_disconnect(int ch_number)
190{
191	struct xpc_registration *registration;
192
193	DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
194
195	registration = &xpc_registrations[ch_number];
196
197	/*
198	 * We've decided not to make this a down_interruptible(), since we
199	 * figured XPC's users will just turn around and call xpc_disconnect()
200	 * again anyways, so we might as well wait, if need be.
201	 */
202	mutex_lock(&registration->mutex);
203
204	/* if !XPC_CHANNEL_REGISTERED(ch_number) */
205	if (registration->func == NULL) {
206		mutex_unlock(&registration->mutex);
207		return;
208	}
209
210	/* remove the connection registration for the specified channel */
211	registration->func = NULL;
212	registration->key = NULL;
213	registration->nentries = 0;
214	registration->entry_size = 0;
215	registration->assigned_limit = 0;
216	registration->idle_limit = 0;
217
218	if (xpc_interface.disconnect)
219		xpc_interface.disconnect(ch_number);
220
221	mutex_unlock(&registration->mutex);
222
223	return;
224}
225EXPORT_SYMBOL_GPL(xpc_disconnect);
226
227static int __init
228xp_init(void)
229{
230	enum xp_retval ret;
231	int ch_number;
232
233	/* initialize the connection registration mutex */
234	for (ch_number = 0; ch_number < XPC_MAX_NCHANNELS; ch_number++)
235		mutex_init(&xpc_registrations[ch_number].mutex);
236
237	if (is_uv_system())
238		ret = xp_init_uv();
239	else
240		ret = 0;
241
242	if (ret != xpSuccess)
243		return ret;
244
245	return 0;
246}
247
248module_init(xp_init);
249
250static void __exit
251xp_exit(void)
252{
253	if (is_uv_system())
254		xp_exit_uv();
255}
256
257module_exit(xp_exit);
258
259MODULE_AUTHOR("Silicon Graphics, Inc.");
260MODULE_DESCRIPTION("Cross Partition (XP) base");
261MODULE_LICENSE("GPL");
262