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 <asm/sn/intr.h>
  23 #include <asm/sn/sn_sal.h>
  24 #include <asm/sn/xp.h>
  25
  26
  27 /*
  28  * Target of nofault PIO read.
  29  */
  30 u64 xp_nofault_PIOR_target;
  31
  32
  33 /*
  34  * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
  35  * users of XPC.
  36  */
  37 struct xpc_registration xpc_registrations[XPC_NCHANNELS];
  38
  39
  40 /*
  41  * Initialize the XPC interface to indicate that XPC isn't loaded.
  42  */
  43 static enum xpc_retval xpc_notloaded(void) { return xpcNotLoaded; }
  44
  45 struct xpc_interface xpc_interface = {
  46         (void (*)(int)) xpc_notloaded,
  47         (void (*)(int)) xpc_notloaded,
  48         (enum xpc_retval (*)(partid_t, int, u32, void **)) xpc_notloaded,
  49         (enum xpc_retval (*)(partid_t, int, void *)) xpc_notloaded,
  50         (enum xpc_retval (*)(partid_t, int, void *, xpc_notify_func, void *))
  51                                                         xpc_notloaded,
  52         (void (*)(partid_t, int, void *)) xpc_notloaded,
  53         (enum xpc_retval (*)(partid_t, void *)) xpc_notloaded
  54 };
  55
  56
  57 /*
  58  * XPC calls this when it (the XPC module) has been loaded.
  59  */
  60 void
  61 xpc_set_interface(void (*connect)(int),
  62                 void (*disconnect)(int),
  63                 enum xpc_retval (*allocate)(partid_t, int, u32, void **),
  64                 enum xpc_retval (*send)(partid_t, int, void *),
  65                 enum xpc_retval (*send_notify)(partid_t, int, void *,
  66                                                 xpc_notify_func, void *),
  67                 void (*received)(partid_t, int, void *),
  68                 enum xpc_retval (*partid_to_nasids)(partid_t, void *))
  69 {
  70         xpc_interface.connect = connect;
  71         xpc_interface.disconnect = disconnect;
  72         xpc_interface.allocate = allocate;
  73         xpc_interface.send = send;
  74         xpc_interface.send_notify = send_notify;
  75         xpc_interface.received = received;
  76         xpc_interface.partid_to_nasids = partid_to_nasids;
  77 }
  78
  79
  80 /*
  81  * XPC calls this when it (the XPC module) is being unloaded.
  82  */
  83 void
  84 xpc_clear_interface(void)
  85 {
  86         xpc_interface.connect = (void (*)(int)) xpc_notloaded;
  87         xpc_interface.disconnect = (void (*)(int)) xpc_notloaded;
  88         xpc_interface.allocate = (enum xpc_retval (*)(partid_t, int, u32,
  89                                         void **)) xpc_notloaded;
  90         xpc_interface.send = (enum xpc_retval (*)(partid_t, int, void *))
  91                                         xpc_notloaded;
  92         xpc_interface.send_notify = (enum xpc_retval (*)(partid_t, int, void *,
  93                                     xpc_notify_func, void *)) xpc_notloaded;
  94         xpc_interface.received = (void (*)(partid_t, int, void *))
  95                                         xpc_notloaded;
  96         xpc_interface.partid_to_nasids = (enum xpc_retval (*)(partid_t, void *))
  97                                         xpc_notloaded;
  98 }
  99
 100
 101 /*
 102  * Register for automatic establishment of a channel connection whenever
 103  * a partition comes up.
 104  *
 105  * Arguments:
 106  *
 107  *      ch_number - channel # to register for connection.
 108  *      func - function to call for asynchronous notification of channel
 109  *             state changes (i.e., connection, disconnection, error) and
 110  *             the arrival of incoming messages.
 111  *      key - pointer to optional user-defined value that gets passed back
 112  *            to the user on any callouts made to func.
 113  *      payload_size - size in bytes of the XPC message's payload area which
 114  *                     contains a user-defined message. The user should make
 115  *                     this large enough to hold their largest message.
 116  *      nentries - max #of XPC message entries a message queue can contain.
 117  *                 The actual number, which is determined when a connection
 118  *                 is established and may be less then requested, will be
 119  *                 passed to the user via the xpcConnected callout.
 120  *      assigned_limit - max number of kthreads allowed to be processing
 121  *                       messages (per connection) at any given instant.
 122  *      idle_limit - max number of kthreads allowed to be idle at any given
 123  *                   instant.
 124  */
 125 enum xpc_retval
 126 xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
 127                 u16 nentries, u32 assigned_limit, u32 idle_limit)
 128 {
 129         struct xpc_registration *registration;
 130
 131
 132         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 133         DBUG_ON(payload_size == 0 || nentries == 0);
 134         DBUG_ON(func == NULL);
 135         DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
 136
 137         registration = &xpc_registrations[ch_number];
 138
 139         if (down_interruptible(&registration->sema) != 0) {
 140                 return xpcInterrupted;
 141         }
 142
 143         /* if XPC_CHANNEL_REGISTERED(ch_number) */
 144         if (registration->func != NULL) {
 145                 up(&registration->sema);
 146                 return xpcAlreadyRegistered;
 147         }
 148
 149         /* register the channel for connection */
 150         registration->msg_size = XPC_MSG_SIZE(payload_size);
 151         registration->nentries = nentries;
 152         registration->assigned_limit = assigned_limit;
 153         registration->idle_limit = idle_limit;
 154         registration->key = key;
 155         registration->func = func;
 156
 157         up(&registration->sema);
 158
 159         xpc_interface.connect(ch_number);
 160
 161         return xpcSuccess;
 162 }
 163
 164
 165 /*
 166  * Remove the registration for automatic connection of the specified channel
 167  * when a partition comes up.
 168  *
 169  * Before returning this xpc_disconnect() will wait for all connections on the
 170  * specified channel have been closed/torndown. So the caller can be assured
 171  * that they will not be receiving any more callouts from XPC to their
 172  * function registered via xpc_connect().
 173  *
 174  * Arguments:
 175  *
 176  *      ch_number - channel # to unregister.
 177  */
 178 void
 179 xpc_disconnect(int ch_number)
 180 {
 181         struct xpc_registration *registration;
 182
 183
 184         DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
 185
 186         registration = &xpc_registrations[ch_number];
 187
 188         /*
 189          * We've decided not to make this a down_interruptible(), since we
 190          * figured XPC's users will just turn around and call xpc_disconnect()
 191          * again anyways, so we might as well wait, if need be.
 192          */
 193         down(&registration->sema);
 194
 195         /* if !XPC_CHANNEL_REGISTERED(ch_number) */
 196         if (registration->func == NULL) {
 197                 up(&registration->sema);
 198                 return;
 199         }
 200
 201         /* remove the connection registration for the specified channel */
 202         registration->func = NULL;
 203         registration->key = NULL;
 204         registration->nentries = 0;
 205         registration->msg_size = 0;
 206         registration->assigned_limit = 0;
 207         registration->idle_limit = 0;
 208
 209         xpc_interface.disconnect(ch_number);
 210
 211         up(&registration->sema);
 212
 213         return;
 214 }
 215
 216
 217 int __init
 218 xp_init(void)
 219 {
 220         int ret, ch_number;
 221         u64 func_addr = *(u64 *) xp_nofault_PIOR;
 222         u64 err_func_addr = *(u64 *) xp_error_PIOR;
 223
 224
 225         if (!ia64_platform_is("sn2")) {
 226                 return -ENODEV;
 227         }
 228
 229         /*
 230          * Register a nofault code region which performs a cross-partition
 231          * PIO read. If the PIO read times out, the MCA handler will consume
 232          * the error and return to a kernel-provided instruction to indicate
 233          * an error. This PIO read exists because it is guaranteed to timeout
 234          * if the destination is down (AMO operations do not timeout on at
 235          * least some CPUs on Shubs <= v1.2, which unfortunately we have to
 236          * work around).
 237          */
 238         if ((ret = sn_register_nofault_code(func_addr, err_func_addr,
 239                                                 err_func_addr, 1, 1)) != 0) {
 240                 printk(KERN_ERR "XP: can't register nofault code, error=%d\n",
 241                         ret);
 242         }
 243         /*
 244          * Setup the nofault PIO read target. (There is no special reason why
 245          * SH_IPI_ACCESS was selected.)
 246          */
 247         if (is_shub2()) {
 248                 xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
 249         } else {
 250                 xp_nofault_PIOR_target = SH1_IPI_ACCESS;
 251         }
 252
 253         /* initialize the connection registration semaphores */
 254         for (ch_number = 0; ch_number < XPC_NCHANNELS; ch_number++) {
 255                 sema_init(&xpc_registrations[ch_number].sema, 1);  /* mutex */
 256         }
 257
 258         return 0;
 259 }
 260 module_init(xp_init);
 261
 262
 263 void __exit
 264 xp_exit(void)
 265 {
 266         u64 func_addr = *(u64 *) xp_nofault_PIOR;
 267         u64 err_func_addr = *(u64 *) xp_error_PIOR;
 268
 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 module_exit(xp_exit);
 275
 276
 277 MODULE_AUTHOR("Silicon Graphics, Inc.");
 278 MODULE_DESCRIPTION("Cross Partition (XP) base");
 279 MODULE_LICENSE("GPL");
 280
 281 EXPORT_SYMBOL(xp_nofault_PIOR);
 282 EXPORT_SYMBOL(xp_nofault_PIOR_target);
 283 EXPORT_SYMBOL(xpc_registrations);
 284 EXPORT_SYMBOL(xpc_interface);
 285 EXPORT_SYMBOL(xpc_clear_interface);
 286 EXPORT_SYMBOL(xpc_set_interface);
 287 EXPORT_SYMBOL(xpc_connect);
 288 EXPORT_SYMBOL(xpc_disconnect);
 289