xref: /linux/drivers/misc/sgi-xp/xp_main.c (revision 8be98d2f2a0a262f8bf8a0bc1fdf522b3c7aab17)
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 
24 static struct device_driver xp_dbg_name = {
25 	.name = "xp"
26 };
27 
28 static struct device xp_dbg_subname = {
29 	.init_name = "",		/* set to "" */
30 	.driver = &xp_dbg_name
31 };
32 
33 struct device *xp = &xp_dbg_subname;
34 
35 /* max #of partitions possible */
36 short xp_max_npartitions;
37 EXPORT_SYMBOL_GPL(xp_max_npartitions);
38 
39 short xp_partition_id;
40 EXPORT_SYMBOL_GPL(xp_partition_id);
41 
42 u8 xp_region_size;
43 EXPORT_SYMBOL_GPL(xp_region_size);
44 
45 unsigned long (*xp_pa) (void *addr);
46 EXPORT_SYMBOL_GPL(xp_pa);
47 
48 unsigned long (*xp_socket_pa) (unsigned long gpa);
49 EXPORT_SYMBOL_GPL(xp_socket_pa);
50 
51 enum xp_retval (*xp_remote_memcpy) (unsigned long dst_gpa,
52 				    const unsigned long src_gpa, size_t len);
53 EXPORT_SYMBOL_GPL(xp_remote_memcpy);
54 
55 int (*xp_cpu_to_nasid) (int cpuid);
56 EXPORT_SYMBOL_GPL(xp_cpu_to_nasid);
57 
58 enum xp_retval (*xp_expand_memprotect) (unsigned long phys_addr,
59 					unsigned long size);
60 EXPORT_SYMBOL_GPL(xp_expand_memprotect);
61 enum xp_retval (*xp_restrict_memprotect) (unsigned long phys_addr,
62 					  unsigned long size);
63 EXPORT_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  */
69 struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
70 EXPORT_SYMBOL_GPL(xpc_registrations);
71 
72 /*
73  * Initialize the XPC interface to NULL to indicate that XPC isn't loaded.
74  */
75 struct xpc_interface xpc_interface = { };
76 EXPORT_SYMBOL_GPL(xpc_interface);
77 
78 /*
79  * XPC calls this when it (the XPC module) has been loaded.
80  */
81 void
xpc_set_interface(void (* connect)(int),void (* disconnect)(int),enum xp_retval (* send)(short,int,u32,void *,u16),enum xp_retval (* send_notify)(short,int,u32,void *,u16,xpc_notify_func,void *),void (* received)(short,int,void *),enum xp_retval (* partid_to_nasids)(short,void *))82 xpc_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 }
97 EXPORT_SYMBOL_GPL(xpc_set_interface);
98 
99 /*
100  * XPC calls this when it (the XPC module) is being unloaded.
101  */
102 void
xpc_clear_interface(void)103 xpc_clear_interface(void)
104 {
105 	memset(&xpc_interface, 0, sizeof(xpc_interface));
106 }
107 EXPORT_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  */
133 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)134 xpc_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 }
173 EXPORT_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  */
188 void
xpc_disconnect(int ch_number)189 xpc_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 }
225 EXPORT_SYMBOL_GPL(xpc_disconnect);
226 
227 static int __init
xp_init(void)228 xp_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 
248 module_init(xp_init);
249 
250 static void __exit
xp_exit(void)251 xp_exit(void)
252 {
253 	if (is_uv_system())
254 		xp_exit_uv();
255 }
256 
257 module_exit(xp_exit);
258 
259 MODULE_AUTHOR("Silicon Graphics, Inc.");
260 MODULE_DESCRIPTION("Cross Partition (XP) base");
261 MODULE_LICENSE("GPL");
262