xpc.h

LINUX 2.6.17.4的源码

/*
 * 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) 2004-2006 Silicon Graphics, Inc.  All Rights Reserved.
 */


/*
 * Cross Partition Communication (XPC) structures and macros.
 */

#ifndef _ASM_IA64_SN_XPC_H
#define _ASM_IA64_SN_XPC_H


#include <linux/config.h>
#include <linux/interrupt.h>
#include <linux/sysctl.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/sn/bte.h>
#include <asm/sn/clksupport.h>
#include <asm/sn/addrs.h>
#include <asm/sn/mspec.h>
#include <asm/sn/shub_mmr.h>
#include <asm/sn/xp.h>


/*
 * XPC Version numbers consist of a major and minor number. XPC can always
 * talk to versions with same major #, and never talk to versions with a
 * different major #.
 */
#define _XPC_VERSION(_maj, _min)	(((_maj) << 4) | ((_min) & 0xf))
#define XPC_VERSION_MAJOR(_v)		((_v) >> 4)
#define XPC_VERSION_MINOR(_v)		((_v) & 0xf)


/*
 * The next macros define word or bit representations for given
 * C-brick nasid in either the SAL provided bit array representing
 * nasids in the partition/machine or the AMO_t array used for
 * inter-partition initiation communications.
 *
 * For SN2 machines, C-Bricks are alway even numbered NASIDs.  As
 * such, some space will be saved by insisting that nasid information
 * passed from SAL always be packed for C-Bricks and the
 * cross-partition interrupts use the same packing scheme.
 */
#define XPC_NASID_W_INDEX(_n)	(((_n) / 64) / 2)
#define XPC_NASID_B_INDEX(_n)	(((_n) / 2) & (64 - 1))
#define XPC_NASID_IN_ARRAY(_n, _p) ((_p)[XPC_NASID_W_INDEX(_n)] & \
				    (1UL << XPC_NASID_B_INDEX(_n)))
#define XPC_NASID_FROM_W_B(_w, _b) (((_w) * 64 + (_b)) * 2)

#define XPC_HB_DEFAULT_INTERVAL		5	/* incr HB every x secs */
#define XPC_HB_CHECK_DEFAULT_INTERVAL	20	/* check HB every x secs */

/* define the process name of HB checker and the CPU it is pinned to */
#define XPC_HB_CHECK_THREAD_NAME	"xpc_hb"
#define XPC_HB_CHECK_CPU		0

/* define the process name of the discovery thread */
#define XPC_DISCOVERY_THREAD_NAME	"xpc_discovery"


/*
 * the reserved page
 *
 *   SAL reserves one page of memory per partition for XPC. Though a full page
 *   in length (16384 bytes), its starting address is not page aligned, but it
 *   is cacheline aligned. The reserved page consists of the following:
 *
 *   reserved page header
 *
 *     The first cacheline of the reserved page contains the header
 *     (struct xpc_rsvd_page). Before SAL initialization has completed,
 *     SAL has set up the following fields of the reserved page header:
 *     SAL_signature, SAL_version, partid, and nasids_size. The other
 *     fields are set up by XPC. (xpc_rsvd_page points to the local
 *     partition's reserved page.)
 *
 *   part_nasids mask
 *   mach_nasids mask
 *
 *     SAL also sets up two bitmaps (or masks), one that reflects the actual
 *     nasids in this partition (part_nasids), and the other that reflects
 *     the actual nasids in the entire machine (mach_nasids). We're only
 *     interested in the even numbered nasids (which contain the processors
 *     and/or memory), so we only need half as many bits to represent the
 *     nasids. The part_nasids mask is located starting at the first cacheline
 *     following the reserved page header. The mach_nasids mask follows right
 *     after the part_nasids mask. The size in bytes of each mask is reflected
 *     by the reserved page header field 'nasids_size'. (Local partition's
 *     mask pointers are xpc_part_nasids and xpc_mach_nasids.)
 *
 *   vars
 *   vars part
 *
 *     Immediately following the mach_nasids mask are the XPC variables
 *     required by other partitions. First are those that are generic to all
 *     partitions (vars), followed on the next available cacheline by those
 *     which are partition specific (vars part). These are setup by XPC.
 *     (Local partition's vars pointers are xpc_vars and xpc_vars_part.)
 *
 * Note: Until vars_pa is set, the partition XPC code has not been initialized.
 */
struct xpc_rsvd_page {
	u64 SAL_signature;	/* SAL: unique signature */
	u64 SAL_version;	/* SAL: version */
	u8 partid;		/* SAL: partition ID */
	u8 version;
	u8 pad1[6];		/* align to next u64 in cacheline */
	volatile u64 vars_pa;
	struct timespec stamp;	/* time when reserved page was setup by XPC */
	u64 pad2[9];		/* align to last u64 in cacheline */
	u64 nasids_size;	/* SAL: size of each nasid mask in bytes */
};

#define XPC_RP_VERSION _XPC_VERSION(1,1) /* version 1.1 of the reserved page */

#define XPC_SUPPORTS_RP_STAMP(_version) \
			(_version >= _XPC_VERSION(1,1))

/*
 * compare stamps - the return value is:
 *
 *	< 0,	if stamp1 < stamp2
 *	= 0,	if stamp1 == stamp2
 *	> 0,	if stamp1 > stamp2
 */
static inline int
xpc_compare_stamps(struct timespec *stamp1, struct timespec *stamp2)
{
	int ret;


	if ((ret = stamp1->tv_sec - stamp2->tv_sec) == 0) {
		ret = stamp1->tv_nsec - stamp2->tv_nsec;
	}
	return ret;
}


/*
 * Define the structures by which XPC variables can be exported to other
 * partitions. (There are two: struct xpc_vars and struct xpc_vars_part)
 */

/*
 * The following structure describes the partition generic variables
 * needed by other partitions in order to properly initialize.
 *
 * struct xpc_vars version number also applies to struct xpc_vars_part.
 * Changes to either structure and/or related functionality should be
 * reflected by incrementing either the major or minor version numbers
 * of struct xpc_vars.
 */
struct xpc_vars {
	u8 version;
	u64 heartbeat;
	u64 heartbeating_to_mask;
	u64 heartbeat_offline;	/* if 0, heartbeat should be changing */
	int act_nasid;
	int act_phys_cpuid;
	u64 vars_part_pa;
	u64 amos_page_pa;	/* paddr of page of AMOs from MSPEC driver */
	AMO_t *amos_page;	/* vaddr of page of AMOs from MSPEC driver */
};

#define XPC_V_VERSION _XPC_VERSION(3,1) /* version 3.1 of the cross vars */

#define XPC_SUPPORTS_DISENGAGE_REQUEST(_version) \
			(_version >= _XPC_VERSION(3,1))


static inline int
xpc_hb_allowed(partid_t partid, struct xpc_vars *vars)
{
	return ((vars->heartbeating_to_mask & (1UL << partid)) != 0);
}

static inline void
xpc_allow_hb(partid_t partid, struct xpc_vars *vars)
{
	u64 old_mask, new_mask;

	do {
		old_mask = vars->heartbeating_to_mask;
		new_mask = (old_mask | (1UL << partid));
	} while (cmpxchg(&vars->heartbeating_to_mask, old_mask, new_mask) !=
							old_mask);
}

static inline void
xpc_disallow_hb(partid_t partid, struct xpc_vars *vars)
{
	u64 old_mask, new_mask;

	do {
		old_mask = vars->heartbeating_to_mask;
		new_mask = (old_mask & ~(1UL << partid));
	} while (cmpxchg(&vars->heartbeating_to_mask, old_mask, new_mask) !=
							old_mask);
}


/*
 * The AMOs page consists of a number of AMO variables which are divided into
 * four groups, The first two groups are used to identify an IRQ's sender.
 * These two groups consist of 64 and 128 AMO variables respectively. The last
 * two groups, consisting of just one AMO variable each, are used to identify
 * the remote partitions that are currently engaged (from the viewpoint of
 * the XPC running on the remote partition).
 */
#define XPC_NOTIFY_IRQ_AMOS	   0
#define XPC_ACTIVATE_IRQ_AMOS	   (XPC_NOTIFY_IRQ_AMOS + XP_MAX_PARTITIONS)
#define XPC_ENGAGED_PARTITIONS_AMO (XPC_ACTIVATE_IRQ_AMOS + XP_NASID_MASK_WORDS)
#define XPC_DISENGAGE_REQUEST_AMO  (XPC_ENGAGED_PARTITIONS_AMO + 1)


/*
 * The following structure describes the per partition specific variables.
 *
 * An array of these structures, one per partition, will be defined. As a
 * partition becomes active XPC will copy the array entry corresponding to
 * itself from that partition. It is desirable that the size of this
 * structure evenly divide into a cacheline, such that none of the entries
 * in this array crosses a cacheline boundary. As it is now, each entry
 * occupies half a cacheline.
 */
struct xpc_vars_part {
	volatile u64 magic;

	u64 openclose_args_pa;	/* physical address of open and close args */
	u64 GPs_pa;		/* physical address of Get/Put values */

	u64 IPI_amo_pa;		/* physical address of IPI AMO_t structure */
	int IPI_nasid;		/* nasid of where to send IPIs */
	int IPI_phys_cpuid;	/* physical CPU ID of where to send IPIs */

	u8 nchannels;		/* #of defined channels supported */

	u8 reserved[23];	/* pad to a full 64 bytes */
};

/*
 * The vars_part MAGIC numbers play a part in the first contact protocol.
 *
 * MAGIC1 indicates that the per partition specific variables for a remote
 * partition have been initialized by this partition.
 *
 * MAGIC2 indicates that this partition has pulled the remote partititions
 * per partition variables that pertain to this partition.
 */
#define XPC_VP_MAGIC1	0x0053524156435058L  /* 'XPCVARS\0'L (little endian) */
#define XPC_VP_MAGIC2	0x0073726176435058L  /* 'XPCvars\0'L (little endian) */


/* the reserved page sizes and offsets */

#define XPC_RP_HEADER_SIZE	L1_CACHE_ALIGN(sizeof(struct xpc_rsvd_page))
#define XPC_RP_VARS_SIZE 	L1_CACHE_ALIGN(sizeof(struct xpc_vars))

#define XPC_RP_PART_NASIDS(_rp) (u64 *) ((u8 *) _rp + XPC_RP_HEADER_SIZE)
#define XPC_RP_MACH_NASIDS(_rp) (XPC_RP_PART_NASIDS(_rp) + xp_nasid_mask_words)
#define XPC_RP_VARS(_rp)	((struct xpc_vars *) XPC_RP_MACH_NASIDS(_rp) + xp_nasid_mask_words)
#define XPC_RP_VARS_PART(_rp)	(struct xpc_vars_part *) ((u8 *) XPC_RP_VARS(rp) + XPC_RP_VARS_SIZE)


/*
 * Functions registered by add_timer() or called by kernel_thread() only
 * allow for a single 64-bit argument. The following macros can be used to
 * pack and unpack two (32-bit, 16-bit or 8-bit) arguments into or out from
 * the passed argument.
 */
#define XPC_PACK_ARGS(_arg1, _arg2) \
			((((u64) _arg1) & 0xffffffff) | \
			((((u64) _arg2) & 0xffffffff) << 32))

#define XPC_UNPACK_ARG1(_args)	(((u64) _args) & 0xffffffff)
#define XPC_UNPACK_ARG2(_args)	((((u64) _args) >> 32) & 0xffffffff)



/*
 * Define a Get/Put value pair (pointers) used with a message queue.
 */
struct xpc_gp {
	volatile s64 get;	/* Get value */
	volatile s64 put;	/* Put value */
};

#define XPC_GP_SIZE \
		L1_CACHE_ALIGN(sizeof(struct xpc_gp) * XPC_NCHANNELS)



/*
 * Define a structure that contains arguments associated with opening and
 * closing a channel.
 */
struct xpc_openclose_args {
	u16 reason;		/* reason why channel is closing */
	u16 msg_size;		/* sizeof each message entry */
	u16 remote_nentries;	/* #of message entries in remote msg queue */
	u16 local_nentries;	/* #of message entries in local msg queue */
	u64 local_msgqueue_pa;	/* physical address of local message queue */
};

#define XPC_OPENCLOSE_ARGS_SIZE \
	      L1_CACHE_ALIGN(sizeof(struct xpc_openclose_args) * XPC_NCHANNELS)



/* struct xpc_msg flags */

#define	XPC_M_DONE		0x01	/* msg has been received/consumed */
#define	XPC_M_READY		0x02	/* msg is ready to be sent */
#define	XPC_M_INTERRUPT		0x04	/* send interrupt when msg consumed */


#define XPC_MSG_ADDRESS(_payload) \
		((struct xpc_msg *)((u8 *)(_payload) - XPC_MSG_PAYLOAD_OFFSET))



/*
 * Defines notify entry.
 *
 * This is used to notify a message's sender that their message was received
 * and consumed by the intended recipient.
 */
struct xpc_notify {
	volatile u8 type;		/* type of notification */

	/* the following two fields are only used if type == XPC_N_CALL */
	xpc_notify_func func;		/* user's notify function */
	void *key;			/* pointer to user's key */
};

/* struct xpc_notify type of notification */

#define	XPC_N_CALL		0x01	/* notify function provided by user */



/*
 * Define the structure that manages all the stuff required by a channel. In
 * particular, they are used to manage the messages sent across the channel.
 *
 * This structure is private to a partition, and is NOT shared across the
 * partition boundary.
 *
 * There is an array of these structures for each remote partition. It is
 * allocated at the time a partition becomes active. The array contains one
 * of these structures for each potential channel connection to that partition.
 *
 * Each of these structures manages two message queues (circular buffers).
 * They are allocated at the time a channel connection is made. One of
 * these message queues (local_msgqueue) holds the locally created messages
 * that are destined for the remote partition. The other of these message
 * queues (remote_msgqueue) is a locally cached copy of the remote partition's
 * own local_msgqueue.
 *
 * The following is a description of the Get/Put pointers used to manage these
 * two message queues. Consider the local_msgqueue to be on one partition
 * and the remote_msgqueue to be its cached copy on another partition. A
 * description of what each of the lettered areas contains is included.
 *
 *
 *                     local_msgqueue      remote_msgqueue
 *
 *                        |/////////|      |/////////|
 *    w_remote_GP.get --> +---------+      |/////////|
 *                        |    F    |      |/////////|
 *     remote_GP.get  --> +---------+      +---------+ <-- local_GP->get
 *                        |         |      |         |
 *                        |         |      |    E    |
 *                        |         |      |         |
 *                        |         |      +---------+ <-- w_local_GP.get
 *                        |    B    |      |/////////|
 *                        |         |      |////D////|
 *                        |         |      |/////////|
 *                        |         |      +---------+ <-- w_remote_GP.put
 *                        |         |      |////C////|
 *      local_GP->put --> +---------+      +---------+ <-- remote_GP.put
 *                        |         |      |/////////|
 *                        |    A    |      |/////////|
 *                        |         |      |/////////|
 *     w_local_GP.put --> +---------+      |/////////|
 *                        |/////////|      |/////////|
 *
 *
 *	    ( remote_GP.[get|put] are cached copies of the remote
 *	      partition's local_GP->[get|put], and thus their values can
 *	      lag behind their counterparts on the remote partition. )
 *
 *
 *  A - Messages that have been allocated, but have not yet been sent to the
 *	remote partition.
 *
 *  B - Messages that have been sent, but have not yet been acknowledged by the
 *      remote partition as having been received.
 *
 *  C - Area that needs to be prepared for the copying of sent messages, by
 *	the clearing of the message flags of any previously received messages.
 *
 *  D - Area into which sent messages are to be copied from the remote
 *	partition's local_msgqueue and then delivered to their intended
 *	recipients. [ To allow for a multi-message copy, another pointer
 *	(next_msg_to_pull) has been added to keep track of the next message
 *	number needing to be copied (pulled). It chases after w_remote_GP.put.
 *	Any messages lying between w_local_GP.get and next_msg_to_pull have
 *	been copied and are ready to be delivered. ]
 *