[PATCH] revert ext3-writepages-support-for-writeback-mode

[linux-2.6] / include / asm-ia64 / sn / xp.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2004-2005 Silicon Graphics, Inc. All rights reserved.
 */


/*
 * External Cross Partition (XP) structures and defines.
 */


#ifndef _ASM_IA64_SN_XP_H
#define _ASM_IA64_SN_XP_H


#include <linux/version.h>
#include <linux/cache.h>
#include <linux/hardirq.h>
#include <asm/sn/types.h>
#include <asm/sn/bte.h>


#ifdef USE_DBUG_ON
#define DBUG_ON(condition)      BUG_ON(condition)
#else
#define DBUG_ON(condition)
#endif


/*
 * Define the maximum number of logically defined partitions the system
 * can support. It is constrained by the maximum number of hardware
 * partitionable regions. The term 'region' in this context refers to the
 * minimum number of nodes that can comprise an access protection grouping.
 * The access protection is in regards to memory, IPI and IOI.
 *
 * The maximum number of hardware partitionable regions is equal to the
 * maximum number of nodes in the entire system divided by the minimum number
 * of nodes that comprise an access protection grouping.
 */
#define XP_MAX_PARTITIONS       64


/*
 * Define the number of u64s required to represent all the C-brick nasids
 * as a bitmap.  The cross-partition kernel modules deal only with
 * C-brick nasids, thus the need for bitmaps which don't account for
 * odd-numbered (non C-brick) nasids.
 */
#define XP_MAX_PHYSNODE_ID      (MAX_PHYSNODE_ID / 2)
#define XP_NASID_MASK_BYTES     ((XP_MAX_PHYSNODE_ID + 7) / 8)
#define XP_NASID_MASK_WORDS     ((XP_MAX_PHYSNODE_ID + 63) / 64)


/*
 * Wrapper for bte_copy() that should it return a failure status will retry
 * the bte_copy() once in the hope that the failure was due to a temporary
 * aberration (i.e., the link going down temporarily).
 *
 * See bte_copy for definition of the input parameters.
 *
 * Note: xp_bte_copy() should never be called while holding a spinlock.
 */
static inline bte_result_t
xp_bte_copy(u64 src, u64 dest, u64 len, u64 mode, void *notification)
{
        bte_result_t ret;


        ret = bte_copy(src, dest, len, mode, notification);

        if (ret != BTE_SUCCESS) {
                if (!in_interrupt()) {
                        cond_resched();
                }
                ret = bte_copy(src, dest, len, mode, notification);
        }

        return ret;
}


/*
 * XPC establishes channel connections between the local partition and any
 * other partition that is currently up. Over these channels, kernel-level
 * `users' can communicate with their counterparts on the other partitions.
 *
 * The maxinum number of channels is limited to eight. For performance reasons,
 * the internal cross partition structures require sixteen bytes per channel,
 * and eight allows all of this interface-shared info to fit in one cache line.
 *
 * XPC_NCHANNELS reflects the total number of channels currently defined.
 * If the need for additional channels arises, one can simply increase
 * XPC_NCHANNELS accordingly. If the day should come where that number
 * exceeds the MAXIMUM number of channels allowed (eight), then one will need
 * to make changes to the XPC code to allow for this.
 */
#define XPC_MEM_CHANNEL         0       /* memory channel number */
#define XPC_NET_CHANNEL         1       /* network channel number */

#define XPC_NCHANNELS           2       /* #of defined channels */
#define XPC_MAX_NCHANNELS       8       /* max #of channels allowed */

#if XPC_NCHANNELS > XPC_MAX_NCHANNELS
#error  XPC_NCHANNELS exceeds MAXIMUM allowed.
#endif


/*
 * The format of an XPC message is as follows:
 *
 *      +-------+--------------------------------+
 *      | flags |////////////////////////////////|
 *      +-------+--------------------------------+
 *      |             message #                  |
 *      +----------------------------------------+
 *      |     payload (user-defined message)     |
 *      |                                        |
 *                      :
 *      |                                        |
 *      +----------------------------------------+
 *
 * The size of the payload is defined by the user via xpc_connect(). A user-
 * defined message resides in the payload area.
 *
 * The user should have no dealings with the message header, but only the
 * message's payload. When a message entry is allocated (via xpc_allocate())
 * a pointer to the payload area is returned and not the actual beginning of
 * the XPC message. The user then constructs a message in the payload area
 * and passes that pointer as an argument on xpc_send() or xpc_send_notify().
 *
 * The size of a message entry (within a message queue) must be a cacheline
 * sized multiple in order to facilitate the BTE transfer of messages from one
 * message queue to another. A macro, XPC_MSG_SIZE(), is provided for the user
 * that wants to fit as many msg entries as possible in a given memory size
 * (e.g. a memory page).
 */
struct xpc_msg {
        u8 flags;               /* FOR XPC INTERNAL USE ONLY */
        u8 reserved[7];         /* FOR XPC INTERNAL USE ONLY */
        s64 number;             /* FOR XPC INTERNAL USE ONLY */

        u64 payload;            /* user defined portion of message */
};


#define XPC_MSG_PAYLOAD_OFFSET  (u64) (&((struct xpc_msg *)0)->payload)
#define XPC_MSG_SIZE(_payload_size) \
                L1_CACHE_ALIGN(XPC_MSG_PAYLOAD_OFFSET + (_payload_size))


/*
 * Define the return values and values passed to user's callout functions.
 * (It is important to add new value codes at the end just preceding
 * xpcUnknownReason, which must have the highest numerical value.)
 */
enum xpc_retval {
        xpcSuccess = 0,

        xpcNotConnected,        /*  1: channel is not connected */
        xpcConnected,           /*  2: channel connected (opened) */
        xpcRETIRED1,            /*  3: (formerly xpcDisconnected) */

        xpcMsgReceived,         /*  4: message received */
        xpcMsgDelivered,        /*  5: message delivered and acknowledged */

        xpcRETIRED2,            /*  6: (formerly xpcTransferFailed) */

        xpcNoWait,              /*  7: operation would require wait */
        xpcRetry,               /*  8: retry operation */
        xpcTimeout,             /*  9: timeout in xpc_allocate_msg_wait() */
        xpcInterrupted,         /* 10: interrupted wait */

        xpcUnequalMsgSizes,     /* 11: message size disparity between sides */
        xpcInvalidAddress,      /* 12: invalid address */

        xpcNoMemory,            /* 13: no memory available for XPC structures */
        xpcLackOfResources,     /* 14: insufficient resources for operation */
        xpcUnregistered,        /* 15: channel is not registered */
        xpcAlreadyRegistered,   /* 16: channel is already registered */

        xpcPartitionDown,       /* 17: remote partition is down */
        xpcNotLoaded,           /* 18: XPC module is not loaded */
        xpcUnloading,           /* 19: this side is unloading XPC module */

        xpcBadMagic,            /* 20: XPC MAGIC string not found */

        xpcReactivating,        /* 21: remote partition was reactivated */

        xpcUnregistering,       /* 22: this side is unregistering channel */
        xpcOtherUnregistering,  /* 23: other side is unregistering channel */

        xpcCloneKThread,        /* 24: cloning kernel thread */
        xpcCloneKThreadFailed,  /* 25: cloning kernel thread failed */

        xpcNoHeartbeat,         /* 26: remote partition has no heartbeat */

        xpcPioReadError,        /* 27: PIO read error */
        xpcPhysAddrRegFailed,   /* 28: registration of phys addr range failed */

        xpcBteDirectoryError,   /* 29: maps to BTEFAIL_DIR */
        xpcBtePoisonError,      /* 30: maps to BTEFAIL_POISON */
        xpcBteWriteError,       /* 31: maps to BTEFAIL_WERR */
        xpcBteAccessError,      /* 32: maps to BTEFAIL_ACCESS */
        xpcBtePWriteError,      /* 33: maps to BTEFAIL_PWERR */
        xpcBtePReadError,       /* 34: maps to BTEFAIL_PRERR */
        xpcBteTimeOutError,     /* 35: maps to BTEFAIL_TOUT */
        xpcBteXtalkError,       /* 36: maps to BTEFAIL_XTERR */
        xpcBteNotAvailable,     /* 37: maps to BTEFAIL_NOTAVAIL */
        xpcBteUnmappedError,    /* 38: unmapped BTEFAIL_ error */

        xpcBadVersion,          /* 39: bad version number */
        xpcVarsNotSet,          /* 40: the XPC variables are not set up */
        xpcNoRsvdPageAddr,      /* 41: unable to get rsvd page's phys addr */
        xpcInvalidPartid,       /* 42: invalid partition ID */
        xpcLocalPartid,         /* 43: local partition ID */

        xpcUnknownReason        /* 44: unknown reason -- must be last in list */
};


/*
 * Define the callout function types used by XPC to update the user on
 * connection activity and state changes (via the user function registered by
 * xpc_connect()) and to notify them of messages received and delivered (via
 * the user function registered by xpc_send_notify()).
 *
 * The two function types are xpc_channel_func and xpc_notify_func and
 * both share the following arguments, with the exception of "data", which
 * only xpc_channel_func has.
 *
 * Arguments:
 *
 *      reason - reason code. (See following table.)
 *      partid - partition ID associated with condition.
 *      ch_number - channel # associated with condition.
 *      data - pointer to optional data. (See following table.)
 *      key - pointer to optional user-defined value provided as the "key"
 *            argument to xpc_connect() or xpc_send_notify().
 *
 * In the following table the "Optional Data" column applies to callouts made
 * to functions registered by xpc_connect(). A "NA" in that column indicates
 * that this reason code can be passed to functions registered by
 * xpc_send_notify() (i.e. they don't have data arguments).
 *
 * Also, the first three reason codes in the following table indicate
 * success, whereas the others indicate failure. When a failure reason code
 * is received, one can assume that the channel is not connected.
 *
 *
 * Reason Code          | Cause                          | Optional Data
 * =====================+================================+=====================
 * xpcConnected         | connection has been established| max #of entries
 *                      | to the specified partition on  | allowed in message
 *                      | the specified channel          | queue
 * ---------------------+--------------------------------+---------------------
 * xpcMsgReceived       | an XPC message arrived from    | address of payload
 *                      | the specified partition on the |
 *                      | specified channel              | [the user must call
 *                      |                                | xpc_received() when
 *                      |                                | finished with the
 *                      |                                | payload]
 * ---------------------+--------------------------------+---------------------
 * xpcMsgDelivered      | notification that the message  | NA
 *                      | was delivered to the intended  |
 *                      | recipient and that they have   |
 *                      | acknowledged its receipt by    |
 *                      | calling xpc_received()         |
 * =====================+================================+=====================
 * xpcUnequalMsgSizes   | can't connect to the specified | NULL
 *                      | partition on the specified     |
 *                      | channel because of mismatched  |
 *                      | message sizes                  |
 * ---------------------+--------------------------------+---------------------
 * xpcNoMemory          | insufficient memory avaiable   | NULL
 *                      | to allocate message queue      |
 * ---------------------+--------------------------------+---------------------
 * xpcLackOfResources   | lack of resources to create    | NULL
 *                      | the necessary kthreads to      |
 *                      | support the channel            |
 * ---------------------+--------------------------------+---------------------
 * xpcUnregistering     | this side's user has           | NULL or NA
 *                      | unregistered by calling        |
 *                      | xpc_disconnect()               |
 * ---------------------+--------------------------------+---------------------
 * xpcOtherUnregistering| the other side's user has      | NULL or NA
 *                      | unregistered by calling        |
 *                      | xpc_disconnect()               |
 * ---------------------+--------------------------------+---------------------
 * xpcNoHeartbeat       | the other side's XPC is no     | NULL or NA
 *                      | longer heartbeating            |
 *                      |                                |
 * ---------------------+--------------------------------+---------------------
 * xpcUnloading         | this side's XPC module is      | NULL or NA
 *                      | being unloaded                 |
 *                      |                                |
 * ---------------------+--------------------------------+---------------------
 * xpcOtherUnloading    | the other side's XPC module is | NULL or NA
 *                      | is being unloaded              |
 *                      |                                |
 * ---------------------+--------------------------------+---------------------
 * xpcPioReadError      | xp_nofault_PIOR() returned an  | NULL or NA
 *                      | error while sending an IPI     |
 *                      |                                |
 * ---------------------+--------------------------------+---------------------
 * xpcInvalidAddress    | the address either received or | NULL or NA
 *                      | sent by the specified partition|
 *                      | is invalid                     |
 * ---------------------+--------------------------------+---------------------
 * xpcBteNotAvailable   | attempt to pull data from the  | NULL or NA
 * xpcBtePoisonError    | specified partition over the   |
 * xpcBteWriteError     | specified channel via a        |
 * xpcBteAccessError    | bte_copy() failed              |
 * xpcBteTimeOutError   |                                |
 * xpcBteXtalkError     |                                |
 * xpcBteDirectoryError |                                |
 * xpcBteGenericError   |                                |
 * xpcBteUnmappedError  |                                |
 * ---------------------+--------------------------------+---------------------
 * xpcUnknownReason     | the specified channel to the   | NULL or NA
 *                      | specified partition was        |
 *                      | unavailable for unknown reasons|
 * =====================+================================+=====================
 */

typedef void (*xpc_channel_func)(enum xpc_retval reason, partid_t partid,
                int ch_number, void *data, void *key);

typedef void (*xpc_notify_func)(enum xpc_retval reason, partid_t partid,
                int ch_number, void *key);


/*
 * The following is a registration entry. There is a global array of these,
 * one per channel. It is used to record the connection registration made
 * by the users of XPC. As long as a registration entry exists, for any
 * partition that comes up, XPC will attempt to establish a connection on
 * that channel. Notification that a connection has been made will occur via
 * the xpc_channel_func function.
 *
 * The 'func' field points to the function to call when aynchronous
 * notification is required for such events as: a connection established/lost,
 * or an incomming message received, or an error condition encountered. A
 * non-NULL 'func' field indicates that there is an active registration for
 * the channel.
 */
struct xpc_registration {
        struct semaphore sema;
        xpc_channel_func func;          /* function to call */
        void *key;                      /* pointer to user's key */
        u16 nentries;                   /* #of msg entries in local msg queue */
        u16 msg_size;                   /* message queue's message size */
        u32 assigned_limit;             /* limit on #of assigned kthreads */
        u32 idle_limit;                 /* limit on #of idle kthreads */
} ____cacheline_aligned;


#define XPC_CHANNEL_REGISTERED(_c)      (xpc_registrations[_c].func != NULL)


/* the following are valid xpc_allocate() flags */
#define XPC_WAIT        0               /* wait flag */
#define XPC_NOWAIT      1               /* no wait flag */


struct xpc_interface {
        void (*connect)(int);
        void (*disconnect)(int);
        enum xpc_retval (*allocate)(partid_t, int, u32, void **);
        enum xpc_retval (*send)(partid_t, int, void *);
        enum xpc_retval (*send_notify)(partid_t, int, void *,
                                                xpc_notify_func, void *);
        void (*received)(partid_t, int, void *);
        enum xpc_retval (*partid_to_nasids)(partid_t, void *);
};


extern struct xpc_interface xpc_interface;

extern void xpc_set_interface(void (*)(int),
                void (*)(int),
                enum xpc_retval (*)(partid_t, int, u32, void **),
                enum xpc_retval (*)(partid_t, int, void *),
                enum xpc_retval (*)(partid_t, int, void *, xpc_notify_func,
                                                                void *),
                void (*)(partid_t, int, void *),
                enum xpc_retval (*)(partid_t, void *));
extern void xpc_clear_interface(void);


extern enum xpc_retval xpc_connect(int, xpc_channel_func, void *, u16,
                                                u16, u32, u32);
extern void xpc_disconnect(int);

static inline enum xpc_retval
xpc_allocate(partid_t partid, int ch_number, u32 flags, void **payload)
{
        return xpc_interface.allocate(partid, ch_number, flags, payload);
}

static inline enum xpc_retval
xpc_send(partid_t partid, int ch_number, void *payload)
{
        return xpc_interface.send(partid, ch_number, payload);
}

static inline enum xpc_retval
xpc_send_notify(partid_t partid, int ch_number, void *payload,
                        xpc_notify_func func, void *key)
{
        return xpc_interface.send_notify(partid, ch_number, payload, func, key);
}

static inline void
xpc_received(partid_t partid, int ch_number, void *payload)
{
        return xpc_interface.received(partid, ch_number, payload);
}

static inline enum xpc_retval
xpc_partid_to_nasids(partid_t partid, void *nasids)
{
        return xpc_interface.partid_to_nasids(partid, nasids);
}


extern u64 xp_nofault_PIOR_target;
extern int xp_nofault_PIOR(void *);
extern int xp_error_PIOR(void);


#endif /* _ASM_IA64_SN_XP_H */