drivers/misc/sgi-xp/xp_main.c

   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  * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   8
   9 /*
  10  * Cross Partition (XP) base.
  11  *
  12  *      XP provides a base from which its users can interact
  13  *      with XPC, yet not be dependent on XPC.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/device.h>
  19 #include "xp.h"
  20
  21 /* define the XP debug device structures to be used with dev_dbg() et al */
  22
  23 struct device_driver xp_dbg_name = {
  24         .name = "xp"
  25 };
  26
  27 struct device xp_dbg_subname = {
  28         .bus_id = {0},          /* set to "" */
  29         .driver = &xp_dbg_name
  30 };
  31
  32 struct device *xp = &xp_dbg_subname;
  33
  34 /* max #of partitions possible */
  35 short xp_max_npartitions;
  36 EXPORT_SYMBOL_GPL(xp_max_npartitions);
  37
  38 short xp_partition_id;
  39 EXPORT_SYMBOL_GPL(xp_partition_id);
  40
  41 u8 xp_region_size;
  42 EXPORT_SYMBOL_GPL(xp_region_size);
  43
  44 unsigned long (*xp_pa) (void *addr);
  45 EXPORT_SYMBOL_GPL(xp_pa);
  46
  47 enum xp_retval (*xp_remote_memcpy) (unsigned long dst_gpa,
  48                                     const unsigned long src_gpa, size_t len);
  49 EXPORT_SYMBOL_GPL(xp_remote_memcpy);
  50
  51 int (*xp_cpu_to_nasid) (int cpuid);
  52 EXPORT_SYMBOL_GPL(xp_cpu_to_nasid);
  53
  54 /*
  55  * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
  56  * users of XPC.
  57  */
  58 struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
  59 EXPORT_SYMBOL_GPL(xpc_registrations);
  60
  61 /*
  62  * Initialize the XPC interface to indicate that XPC isn't loaded.
  63  */
  64 static enum xp_retval
  65 xpc_notloaded(void)
  66 {
  67         return xpNotLoaded;
  68 }
  69
  70 struct xpc_interface xpc_interface = {
  71         (void (*)(int))xpc_notloaded,
  72         (void (*)(int))xpc_notloaded,
  73         (enum xp_retval(*)(short, int, u32, void *, u16))xpc_notloaded,
  74         (enum xp_retval(*)(short, int, u32, void *, u16, xpc_notify_func,
  75                            void *))xpc_notloaded,
  76         (void (*)(short, int, void *))xpc_notloaded,
  77         (enum xp_retval(*)(short, void *))xpc_notloaded
  78 };
  79 EXPORT_SYMBOL_GPL(xpc_interface);
  80
  81 /*
  82  * XPC calls this when it (the XPC module) has been loaded.
  83  */
  84 void
  85 xpc_set_interface(void (*connect) (int),
  86                   void (*disconnect) (int),
  87                   enum xp_retval (*send) (short, int, u32, void *, u16),
  88                   enum xp_retval (*send_notify) (short, int, u32, void *, u16,
  89                                                   xpc_notify_func, void *),
  90                   void (*received) (short, int, void *),
  91                   enum xp_retval (*partid_to_nasids) (short, void *))
  92 {
  93         xpc_interface.connect = connect;
  94         xpc_interface.disconnect = disconnect;
  95         xpc_interface.send = send;
  96         xpc_interface.send_notify = send_notify;
  97         xpc_interface.received = received;
  98         xpc_interface.partid_to_nasids = partid_to_nasids;
  99 }
 100 EXPORT_SYMBOL_GPL(xpc_set_interface);
 101
 102 /*
 103  * XPC calls this when it (the XPC module) is being unloaded.
 104  */
 105 void
 106 xpc_clear_interface(void)
 107 {
 108         xpc_interface.connect = (void (*)(int))xpc_notloaded;
 109         xpc_interface.disconnect = (void (*)(int))xpc_notloaded;
 110         xpc_interface.send = (enum xp_retval(*)(short, int, u32, void *, u16))
 111             xpc_notloaded;
 112         xpc_interface.send_notify = (enum xp_retval(*)(short, int, u32, void *,
 113                                                        u16, xpc_notify_func,
 114                                                        void *))xpc_notloaded;
 115         xpc_interface.received = (void (*)(short, int, void *))
 116             xpc_notloaded;
 117         xpc_interface.partid_to_nasids = (enum xp_retval(*)(short, void *))
 118             xpc_notloaded;
 119 }
 120 EXPORT_SYMBOL_GPL(xpc_clear_interface);
 121
 122 /*
 123  * Register for automatic establishment of a channel connection whenever
 124  * a partition comes up.
 125  *
 126  * Arguments:
 127  *
 128  *      ch_number - channel # to register for connection.
 129  *      func - function to call for asynchronous notification of channel
 130  *             state changes (i.e., connection, disconnection, error) and
 131  *             the arrival of incoming messages.
 132  *      key - pointer to optional user-defined value that gets passed back
 133  *            to the user on any callouts made to func.
 134  *      payload_size - size in bytes of the XPC message's payload area which
 135  *                     contains a user-defined message. The user should make
 136  *                     this large enough to hold their largest message.
 137  *      nentries - max #of XPC message entries a message queue can contain.
 138  *                 The actual number, which is determined when a connection
 139  *                 is established and may be less then requested, will be
 140  *                 passed to the user via the xpConnected callout.
 141  *      assigned_limit - max number of kthreads allowed to be processing
 142  *                       messages (per connection) at any given instant.
 143  *      idle_limit - max number of kthreads allowed to be idle at any given
 144  *                   instant.
 145  */
 146 enum xp_retval
 147 xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
 148             u16 nentries, u32 assigned_limit, u32 idle_limit)
 149 {
 150         struct xpc_registration *registration;
 151
 152         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 153         DBUG_ON(payload_size == 0 || nentries == 0);
 154         DBUG_ON(func == NULL);
 155         DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
 156
 157         if (XPC_MSG_SIZE(payload_size) > XPC_MSG_MAX_SIZE)
 158                 return xpPayloadTooBig;
 159
 160         registration = &xpc_registrations[ch_number];
 161
 162         if (mutex_lock_interruptible(&registration->mutex) != 0)
 163                 return xpInterrupted;
 164
 165         /* if XPC_CHANNEL_REGISTERED(ch_number) */
 166         if (registration->func != NULL) {
 167                 mutex_unlock(&registration->mutex);
 168                 return xpAlreadyRegistered;
 169         }
 170
 171         /* register the channel for connection */
 172         registration->entry_size = XPC_MSG_SIZE(payload_size);
 173         registration->nentries = nentries;
 174         registration->assigned_limit = assigned_limit;
 175         registration->idle_limit = idle_limit;
 176         registration->key = key;
 177         registration->func = func;
 178
 179         mutex_unlock(&registration->mutex);
 180
 181         xpc_interface.connect(ch_number);
 182
 183         return xpSuccess;
 184 }
 185 EXPORT_SYMBOL_GPL(xpc_connect);
 186
 187 /*
 188  * Remove the registration for automatic connection of the specified channel
 189  * when a partition comes up.
 190  *
 191  * Before returning this xpc_disconnect() will wait for all connections on the
 192  * specified channel have been closed/torndown. So the caller can be assured
 193  * that they will not be receiving any more callouts from XPC to their
 194  * function registered via xpc_connect().
 195  *
 196  * Arguments:
 197  *
 198  *      ch_number - channel # to unregister.
 199  */
 200 void
 201 xpc_disconnect(int ch_number)
 202 {
 203         struct xpc_registration *registration;
 204
 205         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 206
 207         registration = &xpc_registrations[ch_number];
 208
 209         /*
 210          * We've decided not to make this a down_interruptible(), since we
 211          * figured XPC's users will just turn around and call xpc_disconnect()
 212          * again anyways, so we might as well wait, if need be.
 213          */
 214         mutex_lock(&registration->mutex);
 215
 216         /* if !XPC_CHANNEL_REGISTERED(ch_number) */
 217         if (registration->func == NULL) {
 218                 mutex_unlock(&registration->mutex);
 219                 return;
 220         }
 221
 222         /* remove the connection registration for the specified channel */
 223         registration->func = NULL;
 224         registration->key = NULL;
 225         registration->nentries = 0;
 226         registration->entry_size = 0;
 227         registration->assigned_limit = 0;
 228         registration->idle_limit = 0;
 229
 230         xpc_interface.disconnect(ch_number);
 231
 232         mutex_unlock(&registration->mutex);
 233
 234         return;
 235 }
 236 EXPORT_SYMBOL_GPL(xpc_disconnect);
 237
 238 int __init
 239 xp_init(void)
 240 {
 241         enum xp_retval ret;
 242         int ch_number;
 243
 244         if (is_shub())
 245                 ret = xp_init_sn2();
 246         else if (is_uv())
 247                 ret = xp_init_uv();
 248         else
 249                 ret = xpUnsupported;
 250
 251         if (ret != xpSuccess)
 252                 return -ENODEV;
 253
 254         /* initialize the connection registration mutex */
 255         for (ch_number = 0; ch_number < XPC_MAX_NCHANNELS; ch_number++)
 256                 mutex_init(&xpc_registrations[ch_number].mutex);
 257
 258         return 0;
 259 }
 260
 261 module_init(xp_init);
 262
 263 void __exit
 264 xp_exit(void)
 265 {
 266         if (is_shub())
 267                 xp_exit_sn2();
 268         else if (is_uv())
 269                 xp_exit_uv();
 270 }
 271
 272 module_exit(xp_exit);
 273
 274 MODULE_AUTHOR("Silicon Graphics, Inc.");
 275 MODULE_DESCRIPTION("Cross Partition (XP) base");
 276 MODULE_LICENSE("GPL");