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  * (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 struct device_driver xp_dbg_name = {
  25         .name = "xp"
  26 };
  27
  28 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
  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
 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
 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
 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
 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
 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");