cq_desc.h
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/*
* Copyright 2014 Cisco Systems, Inc. All rights reserved.
*
* This program is free software; you may redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef _CQ_DESC_H_
#define _CQ_DESC_H_
/*
* Completion queue descriptor types
*/
enum cq_desc_types {
CQ_DESC_TYPE_WQ_ENET = 0,
CQ_DESC_TYPE_DESC_COPY = 1,
CQ_DESC_TYPE_WQ_EXCH = 2,
CQ_DESC_TYPE_RQ_ENET = 3,
CQ_DESC_TYPE_RQ_FCP = 4,
};
/* Completion queue descriptor: 16B
*
* All completion queues have this basic layout. The
* type_specific area is unique for each completion
* queue type.
*/
struct cq_desc {
__le16 completed_index;
__le16 q_number;
u8 type_specific[11];
u8 type_color;
};
#define CQ_DESC_TYPE_BITS 4
#define CQ_DESC_TYPE_MASK ((1 << CQ_DESC_TYPE_BITS) - 1)
#define CQ_DESC_COLOR_MASK 1
#define CQ_DESC_COLOR_SHIFT 7
#define CQ_DESC_Q_NUM_BITS 10
#define CQ_DESC_Q_NUM_MASK ((1 << CQ_DESC_Q_NUM_BITS) - 1)
#define CQ_DESC_COMP_NDX_BITS 12
#define CQ_DESC_COMP_NDX_MASK ((1 << CQ_DESC_COMP_NDX_BITS) - 1)
static inline void cq_desc_dec(const struct cq_desc *desc_arg,
u8 *type, u8 *color, u16 *q_number, u16 *completed_index)
{
const struct cq_desc *desc = desc_arg;
const u8 type_color = desc->type_color;
*color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
/*
* Make sure color bit is read from desc *before* other fields
* are read from desc. Hardware guarantees color bit is last
* bit (byte) written. Adding the rmb() prevents the compiler
* and/or CPU from reordering the reads which would potentially
* result in reading stale values.
*/
rmb();
*type = type_color & CQ_DESC_TYPE_MASK;
*q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;
*completed_index = le16_to_cpu(desc->completed_index) &
CQ_DESC_COMP_NDX_MASK;
}
#endif /* _CQ_DESC_H_ */