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* Copyright (c) 2009, Microsoft Corporation.
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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#ifndef _RING_BUFFER_H_
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#define _RING_BUFFER_H_
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#include <linux/scatterlist.h>
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struct hv_ring_buffer {
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/* Offset in bytes from the start of ring data below */
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volatile u32 write_index;
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/* Offset in bytes from the start of ring data below */
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volatile u32 read_index;
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volatile u32 interrupt_mask;
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/* Pad it to PAGE_SIZE so that data starts on page boundary */
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* The interrupt_mask field is used only for channels but since our
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* vmbus connection also uses this data structure and its data starts
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* here, we commented out this field.
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/* volatile u32 InterruptMask; */
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* Ring data starts here + RingDataStartOffset
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* !!! DO NOT place any fields below this !!!
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} __attribute__((packed));
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struct hv_ring_buffer_info {
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struct hv_ring_buffer *ring_buffer;
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u32 ring_size; /* Include the shared header */
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u32 ring_datasize; /* < ring_size */
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u32 ring_data_startoffset;
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struct hv_ring_buffer_debug_info {
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u32 current_interrupt_mask;
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u32 current_read_index;
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u32 current_write_index;
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u32 bytes_avail_toread;
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u32 bytes_avail_towrite;
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int ringbuffer_init(struct hv_ring_buffer_info *ring_info, void *buffer,
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void ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
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int ringbuffer_write(struct hv_ring_buffer_info *ring_info,
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struct scatterlist *sglist,
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int ringbuffer_peek(struct hv_ring_buffer_info *ring_info, void *buffer,
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int ringbuffer_read(struct hv_ring_buffer_info *ring_info,
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u32 get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *ring_info);
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void dump_ring_info(struct hv_ring_buffer_info *ring_info, char *prefix);
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void ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
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struct hv_ring_buffer_debug_info *debug_info);
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#endif /* _RING_BUFFER_H_ */