linux/drivers/misc/sgi-gru/grukservices.h

/*
 *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */
#ifndef __GRU_KSERVICES_H_
#define __GRU_KSERVICES_H_


/*
 * Message queues using the GRU to send/receive messages.
 *
 * These function allow the user to create a message queue for
 * sending/receiving 1 or 2 cacheline messages using the GRU.
 *
 * Processes SENDING messages will use a kernel CBR/DSR to send
 * the message. This is transparent to the caller.
 *
 * The receiver does not use any GRU resources.
 *
 * The functions support:
 * 	- single receiver
 * 	- multiple senders
 *	- cross partition message
 *
 * Missing features ZZZ:
 * 	- user options for dealing with timeouts, queue full, etc.
 * 	- gru_create_message_queue() needs interrupt vector info
 */

/*
 * Initialize a user allocated chunk of memory to be used as
 * a message queue. The caller must ensure that the queue is
 * in contiguous physical memory and is cacheline aligned.
 *
 * Message queue size is the total number of bytes allocated
 * to the queue including a 2 cacheline header that is used
 * to manage the queue.
 *
 *  Input:
 * 	p	pointer to user allocated memory.
 * 	bytes	size of message queue in bytes
 *
 *  Errors:
 *  	0	OK
 *  	>0	error
 */
extern int gru_create_message_queue(void *p, unsigned int bytes);

/*
 * Send a message to a message queue.
 *
 * Note: The message queue transport mechanism uses the first 32
 * bits of the message. Users should avoid using these bits.
 *
 *
 *   Input:
 * 	xmq	message queue - must be a UV global physical address
 * 	mesg	pointer to message. Must be 64-bit aligned
 * 	bytes	size of message in bytes
 *
 *   Output:
 *      0	message sent
 *     >0	Send failure - see error codes below
 *
 */
extern int gru_send_message_gpa(unsigned long mq_gpa, void *mesg,
						unsigned int bytes);

/* Status values for gru_send_message() */
#define MQE_OK			0	/* message sent successfully */
#define MQE_CONGESTION		1	/* temporary congestion, try again */
#define MQE_QUEUE_FULL		2	/* queue is full */
#define MQE_UNEXPECTED_CB_ERR	3	/* unexpected CB error */
#define MQE_PAGE_OVERFLOW	10	/* BUG - queue overflowed a page */
#define MQE_BUG_NO_RESOURCES	11	/* BUG - could not alloc GRU cb/dsr */

/*
 * Advance the receive pointer for the message queue to the next message.
 * Note: current API requires messages to be gotten & freed in order. Future
 * API extensions may allow for out-of-order freeing.
 *
 *   Input
 * 	mq	message queue
 * 	mesq	message being freed
 */
extern void gru_free_message(void *mq, void *mesq);

/*
 * Get next message from message queue. Returns pointer to
 * message OR NULL if no message present.
 * User must call gru_free_message() after message is processed
 * in order to move the queue pointers to next message.
 *
 *   Input
 * 	mq	message queue
 *
 *   Output:
 *	p	pointer to message
 *	NULL	no message available
 */
extern void *gru_get_next_message(void *mq);


/*
 * Copy data using the GRU. Source or destination can be located in a remote
 * partition.
 *
 *    Input:
 *    	dest_gpa	destination global physical address
 *    	src_gpa		source global physical address
 *    	bytes		number of bytes to copy
 *
 *    Output:
 *	0		OK
 *	>0		error
 */
extern int gru_copy_gpa(unsigned long dest_gpa, unsigned long src_gpa,
							unsigned int bytes);

#endif 		/* __GRU_KSERVICES_H_ */