arch/ia64/sn/kernel/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) 2004-2005 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   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
  19 #include <linux/kernel.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/module.h>
  22 #include <linux/mutex.h>
  23 #include <asm/sn/intr.h>
  24 #include <asm/sn/sn_sal.h>
  25 #include <asm/sn/xp.h>
  26
  27
  28 /*
  29  * Target of nofault PIO read.
  30  */
  31 u64 xp_nofault_PIOR_target;
  32
  33
  34 /*
  35  * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
  36  * users of XPC.
  37  */
  38 struct xpc_registration xpc_registrations[XPC_NCHANNELS];
  39
  40
  41 /*
  42  * Initialize the XPC interface to indicate that XPC isn't loaded.
  43  */
  44 static enum xpc_retval xpc_notloaded(void) { return xpcNotLoaded; }
  45
  46 struct xpc_interface xpc_interface = {
  47         (void (*)(int)) xpc_notloaded,
  48         (void (*)(int)) xpc_notloaded,
  49         (enum xpc_retval (*)(partid_t, int, u32, void **)) xpc_notloaded,
  50         (enum xpc_retval (*)(partid_t, int, void *)) xpc_notloaded,
  51         (enum xpc_retval (*)(partid_t, int, void *, xpc_notify_func, void *))
  52                                                         xpc_notloaded,
  53         (void (*)(partid_t, int, void *)) xpc_notloaded,
  54         (enum xpc_retval (*)(partid_t, void *)) xpc_notloaded
  55 };
  56
  57
  58 /*
  59  * XPC calls this when it (the XPC module) has been loaded.
  60  */
  61 void
  62 xpc_set_interface(void (*connect)(int),
  63                 void (*disconnect)(int),
  64                 enum xpc_retval (*allocate)(partid_t, int, u32, void **),
  65                 enum xpc_retval (*send)(partid_t, int, void *),
  66                 enum xpc_retval (*send_notify)(partid_t, int, void *,
  67                                                 xpc_notify_func, void *),
  68                 void (*received)(partid_t, int, void *),
  69                 enum xpc_retval (*partid_to_nasids)(partid_t, void *))
  70 {
  71         xpc_interface.connect = connect;
  72         xpc_interface.disconnect = disconnect;
  73         xpc_interface.allocate = allocate;
  74         xpc_interface.send = send;
  75         xpc_interface.send_notify = send_notify;
  76         xpc_interface.received = received;
  77         xpc_interface.partid_to_nasids = partid_to_nasids;
  78 }
  79
  80
  81 /*
  82  * XPC calls this when it (the XPC module) is being unloaded.
  83  */
  84 void
  85 xpc_clear_interface(void)
  86 {
  87         xpc_interface.connect = (void (*)(int)) xpc_notloaded;
  88         xpc_interface.disconnect = (void (*)(int)) xpc_notloaded;
  89         xpc_interface.allocate = (enum xpc_retval (*)(partid_t, int, u32,
  90                                         void **)) xpc_notloaded;
  91         xpc_interface.send = (enum xpc_retval (*)(partid_t, int, void *))
  92                                         xpc_notloaded;
  93         xpc_interface.send_notify = (enum xpc_retval (*)(partid_t, int, void *,
  94                                     xpc_notify_func, void *)) xpc_notloaded;
  95         xpc_interface.received = (void (*)(partid_t, int, void *))
  96                                         xpc_notloaded;
  97         xpc_interface.partid_to_nasids = (enum xpc_retval (*)(partid_t, void *))
  98                                         xpc_notloaded;
  99 }
 100
 101
 102 /*
 103  * Register for automatic establishment of a channel connection whenever
 104  * a partition comes up.
 105  *
 106  * Arguments:
 107  *
 108  *      ch_number - channel # to register for connection.
 109  *      func - function to call for asynchronous notification of channel
 110  *             state changes (i.e., connection, disconnection, error) and
 111  *             the arrival of incoming messages.
 112  *      key - pointer to optional user-defined value that gets passed back
 113  *            to the user on any callouts made to func.
 114  *      payload_size - size in bytes of the XPC message's payload area which
 115  *                     contains a user-defined message. The user should make
 116  *                     this large enough to hold their largest message.
 117  *      nentries - max #of XPC message entries a message queue can contain.
 118  *                 The actual number, which is determined when a connection
 119  *                 is established and may be less then requested, will be
 120  *                 passed to the user via the xpcConnected callout.
 121  *      assigned_limit - max number of kthreads allowed to be processing
 122  *                       messages (per connection) at any given instant.
 123  *      idle_limit - max number of kthreads allowed to be idle at any given
 124  *                   instant.
 125  */
 126 enum xpc_retval
 127 xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
 128                 u16 nentries, u32 assigned_limit, u32 idle_limit)
 129 {
 130         struct xpc_registration *registration;
 131
 132
 133         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 134         DBUG_ON(payload_size == 0 || nentries == 0);
 135         DBUG_ON(func == NULL);
 136         DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
 137
 138         registration = &xpc_registrations[ch_number];
 139
 140         if (mutex_lock_interruptible(&registration->mutex) != 0) {
 141                 return xpcInterrupted;
 142         }
 143
 144         /* if XPC_CHANNEL_REGISTERED(ch_number) */
 145         if (registration->func != NULL) {
 146                 mutex_unlock(&registration->mutex);
 147                 return xpcAlreadyRegistered;
 148         }
 149
 150         /* register the channel for connection */
 151         registration->msg_size = XPC_MSG_SIZE(payload_size);
 152         registration->nentries = nentries;
 153         registration->assigned_limit = assigned_limit;
 154         registration->idle_limit = idle_limit;
 155         registration->key = key;
 156         registration->func = func;
 157
 158         mutex_unlock(&registration->mutex);
 159
 160         xpc_interface.connect(ch_number);
 161
 162         return xpcSuccess;
 163 }
 164
 165
 166 /*
 167  * Remove the registration for automatic connection of the specified channel
 168  * when a partition comes up.
 169  *
 170  * Before returning this xpc_disconnect() will wait for all connections on the
 171  * specified channel have been closed/torndown. So the caller can be assured
 172  * that they will not be receiving any more callouts from XPC to their
 173  * function registered via xpc_connect().
 174  *
 175  * Arguments:
 176  *
 177  *      ch_number - channel # to unregister.
 178  */
 179 void
 180 xpc_disconnect(int ch_number)
 181 {
 182         struct xpc_registration *registration;
 183
 184
 185         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 186
 187         registration = &xpc_registrations[ch_number];
 188
 189         /*
 190          * We've decided not to make this a down_interruptible(), since we
 191          * figured XPC's users will just turn around and call xpc_disconnect()
 192          * again anyways, so we might as well wait, if need be.
 193          */
 194         mutex_lock(&registration->mutex);
 195
 196         /* if !XPC_CHANNEL_REGISTERED(ch_number) */
 197         if (registration->func == NULL) {
 198                 mutex_unlock(&registration->mutex);
 199                 return;
 200         }
 201
 202         /* remove the connection registration for the specified channel */
 203         registration->func = NULL;
 204         registration->key = NULL;
 205         registration->nentries = 0;
 206         registration->msg_size = 0;
 207         registration->assigned_limit = 0;
 208         registration->idle_limit = 0;
 209
 210         xpc_interface.disconnect(ch_number);
 211
 212         mutex_unlock(&registration->mutex);
 213
 214         return;
 215 }
 216
 217
 218 int __init
 219 xp_init(void)
 220 {
 221         int ret, ch_number;
 222         u64 func_addr = *(u64 *) xp_nofault_PIOR;
 223         u64 err_func_addr = *(u64 *) xp_error_PIOR;
 224
 225
 226         if (!ia64_platform_is("sn2")) {
 227                 return -ENODEV;
 228         }
 229
 230         /*
 231          * Register a nofault code region which performs a cross-partition
 232          * PIO read. If the PIO read times out, the MCA handler will consume
 233          * the error and return to a kernel-provided instruction to indicate
 234          * an error. This PIO read exists because it is guaranteed to timeout
 235          * if the destination is down (AMO operations do not timeout on at
 236          * least some CPUs on Shubs <= v1.2, which unfortunately we have to
 237          * work around).
 238          */
 239         if ((ret = sn_register_nofault_code(func_addr, err_func_addr,
 240                                                 err_func_addr, 1, 1)) != 0) {
 241                 printk(KERN_ERR "XP: can't register nofault code, error=%d\n",
 242                         ret);
 243         }
 244         /*
 245          * Setup the nofault PIO read target. (There is no special reason why
 246          * SH_IPI_ACCESS was selected.)
 247          */
 248         if (is_shub2()) {
 249                 xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
 250         } else {
 251                 xp_nofault_PIOR_target = SH1_IPI_ACCESS;
 252         }
 253
 254         /* initialize the connection registration mutex */
 255         for (ch_number = 0; ch_number < XPC_NCHANNELS; ch_number++) {
 256                 mutex_init(&xpc_registrations[ch_number].mutex);
 257         }
 258
 259         return 0;
 260 }
 261 module_init(xp_init);
 262
 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
 271         /* unregister the PIO read nofault code region */
 272         (void) sn_register_nofault_code(func_addr, err_func_addr,
 273                                         err_func_addr, 1, 0);
 274 }
 275 module_exit(xp_exit);
 276
 277
 278 MODULE_AUTHOR("Silicon Graphics, Inc.");
 279 MODULE_DESCRIPTION("Cross Partition (XP) base");
 280 MODULE_LICENSE("GPL");
 281
 282 EXPORT_SYMBOL(xp_nofault_PIOR);
 283 EXPORT_SYMBOL(xp_nofault_PIOR_target);
 284 EXPORT_SYMBOL(xpc_registrations);
 285 EXPORT_SYMBOL(xpc_interface);
 286 EXPORT_SYMBOL(xpc_clear_interface);
 287 EXPORT_SYMBOL(xpc_set_interface);
 288 EXPORT_SYMBOL(xpc_connect);
 289 EXPORT_SYMBOL(xpc_disconnect);
 290