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/*
*
* Copyright (c) 2009, Microsoft Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
*
*/
#ifndef _RING_BUFFER_H_
#define _RING_BUFFER_H_
#include <linux/scatterlist.h>
struct hv_ring_buffer {
/* Offset in bytes from the start of ring data below */
volatile u32 write_index;
/* Offset in bytes from the start of ring data below */
volatile u32 read_index;
volatile u32 interrupt_mask;
/* Pad it to PAGE_SIZE so that data starts on page boundary */
u8 reserved[4084];
/* NOTE:
* The interrupt_mask field is used only for channels but since our
* vmbus connection also uses this data structure and its data starts
* here, we commented out this field.
*/
/* volatile u32 InterruptMask; */
/*
* Ring data starts here + RingDataStartOffset
* !!! DO NOT place any fields below this !!!
*/
u8 buffer[0];
} __attribute__((packed));
struct hv_ring_buffer_info {
struct hv_ring_buffer *ring_buffer;
u32 ring_size; /* Include the shared header */
spinlock_t ring_lock;
u32 ring_datasize; /* < ring_size */
u32 ring_data_startoffset;
};
struct hv_ring_buffer_debug_info {
u32 current_interrupt_mask;
u32 current_read_index;
u32 current_write_index;
u32 bytes_avail_toread;
u32 bytes_avail_towrite;
};
/* Interface */
int ringbuffer_init(struct hv_ring_buffer_info *ring_info, void *buffer,
u32 buflen);
void ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
int ringbuffer_write(struct hv_ring_buffer_info *ring_info,
struct scatterlist *sglist,
u32 sgcount);
int ringbuffer_peek(struct hv_ring_buffer_info *ring_info, void *buffer,
u32 buflen);
int ringbuffer_read(struct hv_ring_buffer_info *ring_info,
void *buffer,
u32 buflen,
u32 offset);
u32 get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *ring_info);
void dump_ring_info(struct hv_ring_buffer_info *ring_info, char *prefix);
void ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info);
#endif /* _RING_BUFFER_H_ */
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