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/kernel.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <asm/sn/intr.h>
  22 #include <asm/sn/sn_sal.h>
  23 #include "xp.h"
  24
  25 /*
  26  * The export of xp_nofault_PIOR needs to happen here since it is defined
  27  * in drivers/misc/sgi-xp/xp_nofault.S. The target of the nofault read is
  28  * defined here.
  29  */
  30 EXPORT_SYMBOL_GPL(xp_nofault_PIOR);
  31
  32 u64 xp_nofault_PIOR_target;
  33 EXPORT_SYMBOL_GPL(xp_nofault_PIOR_target);
  34
  35 /*
  36  * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
  37  * users of XPC.
  38  */
  39 struct xpc_registration xpc_registrations[XPC_NCHANNELS];
  40 EXPORT_SYMBOL_GPL(xpc_registrations);
  41
  42 /*
  43  * Initialize the XPC interface to indicate that XPC isn't loaded.
  44  */
  45 static enum xp_retval
  46 xpc_notloaded(void)
  47 {
  48         return xpNotLoaded;
  49 }
  50
  51 struct xpc_interface xpc_interface = {
  52         (void (*)(int))xpc_notloaded,
  53         (void (*)(int))xpc_notloaded,
  54         (enum xp_retval(*)(short, int, u32, void **))xpc_notloaded,
  55         (enum xp_retval(*)(short, int, void *))xpc_notloaded,
  56         (enum xp_retval(*)(short, int, void *, xpc_notify_func, void *))
  57             xpc_notloaded,
  58         (void (*)(short, int, void *))xpc_notloaded,
  59         (enum xp_retval(*)(short, void *))xpc_notloaded
  60 };
  61 EXPORT_SYMBOL_GPL(xpc_interface);
  62
  63 /*
  64  * XPC calls this when it (the XPC module) has been loaded.
  65  */
  66 void
  67 xpc_set_interface(void (*connect) (int),
  68                   void (*disconnect) (int),
  69                   enum xp_retval (*allocate) (short, int, u32, void **),
  70                   enum xp_retval (*send) (short, int, void *),
  71                   enum xp_retval (*send_notify) (short, int, void *,
  72                                                   xpc_notify_func, void *),
  73                   void (*received) (short, int, void *),
  74                   enum xp_retval (*partid_to_nasids) (short, void *))
  75 {
  76         xpc_interface.connect = connect;
  77         xpc_interface.disconnect = disconnect;
  78         xpc_interface.allocate = allocate;
  79         xpc_interface.send = send;
  80         xpc_interface.send_notify = send_notify;
  81         xpc_interface.received = received;
  82         xpc_interface.partid_to_nasids = partid_to_nasids;
  83 }
  84 EXPORT_SYMBOL_GPL(xpc_set_interface);
  85
  86 /*
  87  * XPC calls this when it (the XPC module) is being unloaded.
  88  */
  89 void
  90 xpc_clear_interface(void)
  91 {
  92         xpc_interface.connect = (void (*)(int))xpc_notloaded;
  93         xpc_interface.disconnect = (void (*)(int))xpc_notloaded;
  94         xpc_interface.allocate = (enum xp_retval(*)(short, int, u32,
  95                                                      void **))xpc_notloaded;
  96         xpc_interface.send = (enum xp_retval(*)(short, int, void *))
  97             xpc_notloaded;
  98         xpc_interface.send_notify = (enum xp_retval(*)(short, int, void *,
  99                                                         xpc_notify_func,
 100                                                         void *))xpc_notloaded;
 101         xpc_interface.received = (void (*)(short, int, void *))
 102             xpc_notloaded;
 103         xpc_interface.partid_to_nasids = (enum xp_retval(*)(short, void *))
 104             xpc_notloaded;
 105 }
 106 EXPORT_SYMBOL_GPL(xpc_clear_interface);
 107
 108 /*
 109  * Register for automatic establishment of a channel connection whenever
 110  * a partition comes up.
 111  *
 112  * Arguments:
 113  *
 114  *      ch_number - channel # to register for connection.
 115  *      func - function to call for asynchronous notification of channel
 116  *             state changes (i.e., connection, disconnection, error) and
 117  *             the arrival of incoming messages.
 118  *      key - pointer to optional user-defined value that gets passed back
 119  *            to the user on any callouts made to func.
 120  *      payload_size - size in bytes of the XPC message's payload area which
 121  *                     contains a user-defined message. The user should make
 122  *                     this large enough to hold their largest message.
 123  *      nentries - max #of XPC message entries a message queue can contain.
 124  *                 The actual number, which is determined when a connection
 125  *                 is established and may be less then requested, will be
 126  *                 passed to the user via the xpConnected callout.
 127  *      assigned_limit - max number of kthreads allowed to be processing
 128  *                       messages (per connection) at any given instant.
 129  *      idle_limit - max number of kthreads allowed to be idle at any given
 130  *                   instant.
 131  */
 132 enum xp_retval
 133 xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
 134             u16 nentries, u32 assigned_limit, u32 idle_limit)
 135 {
 136         struct xpc_registration *registration;
 137
 138         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 139         DBUG_ON(payload_size == 0 || nentries == 0);
 140         DBUG_ON(func == NULL);
 141         DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
 142
 143         registration = &xpc_registrations[ch_number];
 144
 145         if (mutex_lock_interruptible(&registration->mutex) != 0)
 146                 return xpInterrupted;
 147
 148         /* if XPC_CHANNEL_REGISTERED(ch_number) */
 149         if (registration->func != NULL) {
 150                 mutex_unlock(&registration->mutex);
 151                 return xpAlreadyRegistered;
 152         }
 153
 154         /* register the channel for connection */
 155         registration->msg_size = XPC_MSG_SIZE(payload_size);
 156         registration->nentries = nentries;
 157         registration->assigned_limit = assigned_limit;
 158         registration->idle_limit = idle_limit;
 159         registration->key = key;
 160         registration->func = func;
 161
 162         mutex_unlock(&registration->mutex);
 163
 164         xpc_interface.connect(ch_number);
 165
 166         return xpSuccess;
 167 }
 168 EXPORT_SYMBOL_GPL(xpc_connect);
 169
 170 /*
 171  * Remove the registration for automatic connection of the specified channel
 172  * when a partition comes up.
 173  *
 174  * Before returning this xpc_disconnect() will wait for all connections on the
 175  * specified channel have been closed/torndown. So the caller can be assured
 176  * that they will not be receiving any more callouts from XPC to their
 177  * function registered via xpc_connect().
 178  *
 179  * Arguments:
 180  *
 181  *      ch_number - channel # to unregister.
 182  */
 183 void
 184 xpc_disconnect(int ch_number)
 185 {
 186         struct xpc_registration *registration;
 187
 188         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 189
 190         registration = &xpc_registrations[ch_number];
 191
 192         /*
 193          * We've decided not to make this a down_interruptible(), since we
 194          * figured XPC's users will just turn around and call xpc_disconnect()
 195          * again anyways, so we might as well wait, if need be.
 196          */
 197         mutex_lock(&registration->mutex);
 198
 199         /* if !XPC_CHANNEL_REGISTERED(ch_number) */
 200         if (registration->func == NULL) {
 201                 mutex_unlock(&registration->mutex);
 202                 return;
 203         }
 204
 205         /* remove the connection registration for the specified channel */
 206         registration->func = NULL;
 207         registration->key = NULL;
 208         registration->nentries = 0;
 209         registration->msg_size = 0;
 210         registration->assigned_limit = 0;
 211         registration->idle_limit = 0;
 212
 213         xpc_interface.disconnect(ch_number);
 214
 215         mutex_unlock(&registration->mutex);
 216
 217         return;
 218 }
 219 EXPORT_SYMBOL_GPL(xpc_disconnect);
 220
 221 int __init
 222 xp_init(void)
 223 {
 224         int ret, ch_number;
 225         u64 func_addr = *(u64 *)xp_nofault_PIOR;
 226         u64 err_func_addr = *(u64 *)xp_error_PIOR;
 227
 228         if (!ia64_platform_is("sn2"))
 229                 return -ENODEV;
 230
 231         /*
 232          * Register a nofault code region which performs a cross-partition
 233          * PIO read. If the PIO read times out, the MCA handler will consume
 234          * the error and return to a kernel-provided instruction to indicate
 235          * an error. This PIO read exists because it is guaranteed to timeout
 236          * if the destination is down (AMO operations do not timeout on at
 237          * least some CPUs on Shubs <= v1.2, which unfortunately we have to
 238          * work around).
 239          */
 240         ret = sn_register_nofault_code(func_addr, err_func_addr, err_func_addr,
 241                                        1, 1);
 242         if (ret != 0) {
 243                 printk(KERN_ERR "XP: can't register nofault code, error=%d\n",
 244                        ret);
 245         }
 246         /*
 247          * Setup the nofault PIO read target. (There is no special reason why
 248          * SH_IPI_ACCESS was selected.)
 249          */
 250         if (is_shub2())
 251                 xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
 252         else
 253                 xp_nofault_PIOR_target = SH1_IPI_ACCESS;
 254
 255         /* initialize the connection registration mutex */
 256         for (ch_number = 0; ch_number < XPC_NCHANNELS; ch_number++)
 257                 mutex_init(&xpc_registrations[ch_number].mutex);
 258
 259         return 0;
 260 }
 261
 262 module_init(xp_init);
 263
 264 void __exit
 265 xp_exit(void)
 266 {
 267         u64 func_addr = *(u64 *)xp_nofault_PIOR;
 268         u64 err_func_addr = *(u64 *)xp_error_PIOR;
 269
 270         /* unregister the PIO read nofault code region */
 271         (void)sn_register_nofault_code(func_addr, err_func_addr,
 272                                        err_func_addr, 1, 0);
 273 }
 274
 275 module_exit(xp_exit);
 276
 277 MODULE_AUTHOR("Silicon Graphics, Inc.");
 278 MODULE_DESCRIPTION("Cross Partition (XP) base");
 279 MODULE_LICENSE("GPL");