diff options
Diffstat (limited to 'drivers/misc/mic/scif/scif_rb.h')
| -rw-r--r-- | drivers/misc/mic/scif/scif_rb.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/misc/mic/scif/scif_rb.h b/drivers/misc/mic/scif/scif_rb.h new file mode 100644 index 000000000000..166dffe3093d --- /dev/null +++ b/drivers/misc/mic/scif/scif_rb.h @@ -0,0 +1,100 @@ +/* + * Intel MIC Platform Software Stack (MPSS) + * + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * GPL LICENSE SUMMARY + * + * Copyright(c) 2014 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * 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. + * + * BSD LICENSE + * + * Copyright(c) 2014 Intel Corporation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Intel SCIF driver. + */ +#ifndef SCIF_RB_H +#define SCIF_RB_H +/* + * This file describes a general purpose, byte based ring buffer. Writers to the + * ring buffer need to synchronize using a lock. The same is true for readers, + * although in practice, the ring buffer has a single reader. It is lockless + * between producer and consumer so it can handle being used across the PCIe + * bus. The ring buffer ensures that there are no reads across the PCIe bus for + * performance reasons. Two of these are used to form a single bidirectional + * queue-pair across PCIe. + */ +/* + * struct scif_rb - SCIF Ring Buffer + * + * @rb_base: The base of the memory used for storing RB messages + * @read_ptr: Pointer to the read offset + * @write_ptr: Pointer to the write offset + * @size: Size of the memory in rb_base + * @current_read_offset: Cached read offset for performance + * @current_write_offset: Cached write offset for performance + */ +struct scif_rb { + void *rb_base; + u32 *read_ptr; + u32 *write_ptr; + u32 size; + u32 current_read_offset; + u32 current_write_offset; +}; + +/* methods used by both */ +void scif_rb_init(struct scif_rb *rb, u32 *read_ptr, u32 *write_ptr, + void *rb_base, u8 size); +/* writer only methods */ +/* write a new command, then scif_rb_commit() */ +int scif_rb_write(struct scif_rb *rb, void *msg, u32 size); +/* after write(), then scif_rb_commit() */ +void scif_rb_commit(struct scif_rb *rb); +/* query space available for writing to a RB. */ +u32 scif_rb_space(struct scif_rb *rb); + +/* reader only methods */ +/* read a new message from the ring buffer of size bytes */ +u32 scif_rb_get_next(struct scif_rb *rb, void *msg, u32 size); +/* update the read pointer so that the space can be reused */ +void scif_rb_update_read_ptr(struct scif_rb *rb); +/* count the number of bytes that can be read */ +u32 scif_rb_count(struct scif_rb *rb, u32 size); +#endif |